Stress Ulcer Prophylaxis in Critical Care

Quick Answer Card

Stress Ulcer Prophylaxis (SUP) refers to pharmacological prevention of stress-related mucosal disease (SRMD) and clinically significant upper gastrointestinal (GI) bleeding in critically ill patients.

Key Points for Rapid Reference:

• Clinically significant GI bleeding occurs in only 1-4% of ICU patients with modern care (down from 15-20% historically) [1,2]
• Risk factors (Cook 1994): Mechanical ventilation >48 hours (OR 15.6), coagulopathy (OR 4.3) - these are the only independently significant factors [3]
• SUP-ICU Trial (2018): Pantoprazole 40 mg IV vs placebo - no difference in 90-day mortality (31.1% vs 30.4%) or clinically important bleeding (2.5% vs 4.2%, p=0.04 favoring PPI but below clinical significance threshold) [4]
• PEPTIC Trial (2020): PPIs vs H2RAs - no mortality difference at 90 days (18.3% vs 17.5%, p=0.054); PPIs reduced GI bleeding (1.3% vs 1.8%) [5]
• Current practice: SUP indicated for high-risk patients (MV >48h + coagulopathy); consider omitting in low-risk patients, especially those receiving enteral nutrition
• Agents: PPIs (pantoprazole 40 mg IV/PO daily) or H2RAs (famotidine 20 mg IV BD) - both acceptable [6]
• Controversies: PPIs associated with increased C. difficile, pneumonia risk; benefit unclear in low-risk patients; enteral nutrition may provide adequate protection [7,8]

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CICM Exam Focus

What Examiners Expect

Second Part Written (SAQ):

Common SAQ stems:

• "Outline the evidence base for stress ulcer prophylaxis in critically ill patients, with reference to the SUP-ICU and PEPTIC trials."
• "A 55-year-old patient is admitted to ICU requiring mechanical ventilation. Discuss your approach to stress ulcer prophylaxis, including indications, agent selection, and duration."
• "Compare and contrast proton pump inhibitors and histamine-2 receptor antagonists for stress ulcer prophylaxis in the ICU setting."

Expected depth:

• Knowledge of landmark trials (SUP-ICU, PEPTIC) and their limitations
• Risk stratification using Cook's criteria
• Pharmacology of PPIs and H2RAs (mechanism, tachyphylaxis, drug interactions)
• Adverse effect profile and risk-benefit analysis
• Role of enteral nutrition in mucosal protection
• De-escalation and discontinuation criteria

Second Part Hot Case:

Typical presentations:

• ICU patient with new upper GI bleeding while on or off prophylaxis
• Long-stay patient on PPI with new C. difficile infection
• Weaning patient - should SUP be continued or discontinued?

Examiners assess:

• Systematic A-E examination with focus on hemodynamic stability
• Recognition of GI bleeding (melena, hematemesis, dropping Hb, unexplained shock)
• Appropriate escalation (endoscopy referral, resuscitation, transfusion strategy)
• Evidence-based discussion of SUP indications and agent selection
• Understanding of adverse effects and de-escalation

Second Part Viva:

Expected discussion areas:

• Pathophysiology of stress-related mucosal disease
• Interpretation of SUP-ICU and PEPTIC trial results
• Pharmacology: PPI mechanism (H+/K+-ATPase inhibition), H2RA mechanism, tachyphylaxis
• Risk-benefit analysis in different patient populations
• Australian/NZ practice and guideline recommendations
• Enteral nutrition as mucosal protection strategy

Examiner expectations:

• Safe, evidence-based practice
• Critical appraisal of trial evidence
• Understanding of NNT and clinical significance
• Consideration of adverse effects (C. diff, pneumonia, drug interactions)
• Practical de-escalation strategies

Common Mistakes

• Quoting outdated bleeding rates (15-20%) instead of modern rates (1-4%)
• Not knowing the primary and secondary outcomes of SUP-ICU and PEPTIC trials
• Failing to discuss Cook's risk factors (MV >48h, coagulopathy)
• Not mentioning tachyphylaxis with H2RAs
• Ignoring drug interactions with PPIs (clopidogrel, phenytoin)
• Recommending indefinite prophylaxis without discussing de-escalation
• Not considering enteral nutrition's protective role

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Key Points

Must-Know Facts

1. Stress-Related Mucosal Disease (SRMD): Distinct from peptic ulcer disease; caused by splanchnic hypoperfusion, mucosal ischemia, loss of protective prostaglandins, and impaired bicarbonate secretion in critical illness. [9]

2. Historical Context: Before routine SUP, clinically significant GI bleeding occurred in 15-20% of ICU patients; modern rates are 1-4% with prophylaxis and improved resuscitation practices. [1,2]

3. Cook's Risk Factors (1994): Only two independent risk factors for clinically important GI bleeding: mechanical ventilation >48 hours (OR 15.6) and coagulopathy (OR 4.3). [3]

4. SUP-ICU Trial (2018): Largest placebo-controlled trial (3,298 patients); pantoprazole 40 mg IV daily vs placebo showed no difference in 90-day mortality (31.1% vs 30.4%) or clinically important bleeding (2.5% vs 4.2%). [4]

5. PEPTIC Trial (2020): Largest comparative trial (26,828 patients); PPIs vs H2RAs showed no difference in 90-day mortality (18.3% vs 17.5%, p=0.054); PPIs reduced GI bleeding (1.3% vs 1.8%, p<0.05). [5]

6. PPIs vs H2RAs: PPIs provide more potent and sustained acid suppression; H2RAs develop tachyphylaxis within 48-72 hours but may have lower C. difficile/pneumonia risk (though PEPTIC showed similar rates). [10,11]

7. Enteral Nutrition: May provide equivalent mucosal protection to pharmacological prophylaxis by maintaining mucosal blood flow and providing luminal nutrients; some guidelines suggest EN alone may be sufficient in low-risk patients. [12,13]

8. C. difficile Risk: Both PPIs and H2RAs associated with increased CDI risk (OR 1.3-2.0 for PPIs); gastric acid suppression allows C. difficile spore survival. [14,15]

9. Pneumonia Risk: Controversial; gastric colonization with pathogens increases with acid suppression; meta-analyses show mixed results (OR 1.2-1.5 for VAP). [16,17]

10. Drug Interactions: PPIs inhibit CYP2C19 and CYP3A4; significant interactions with clopidogrel (reduced antiplatelet effect), phenytoin, tacrolimus, methotrexate. [18]

11. De-escalation: SUP should be discontinued when risk factors resolve (extubation, reversal of coagulopathy, resumption of enteral nutrition); hospital-wide stewardship programs reduce inappropriate continuation. [19]

12. Australian Context: ANZICS does not mandate SUP in all ICU patients; local practice varies; eTG recommends individualized approach based on risk factors. [20]

Memory Aids

Mnemonic "COOK'S RISK" - Stress Ulcer Risk Factors:

• Coagulopathy (INR >1.5, platelets <50, therapeutic anticoagulation)
• Over 48 hours mechanical ventilation
• Other factors (burns >35% TBSA, hepatic failure, spinal cord injury)
• Kidney failure (requiring RRT)
• Severe sepsis and shock

Mnemonic "PEPTIC" - Trial Key Points:

• PPI vs H2RA comparison
• Equivalent mortality at 90 days
• PPI reduced bleeding (1.3% vs 1.8%)
• Trend toward higher mortality with PPI (p=0.054)
• ICU patients on mechanical ventilation
• Cluster-randomized design (50 ICUs, 5 countries)

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1. Definition and Epidemiology

Definition

Stress Ulcer Prophylaxis (SUP) is the pharmacological prevention of stress-related mucosal disease (SRMD) and clinically significant upper gastrointestinal bleeding in critically ill patients.

Stress-Related Mucosal Disease (SRMD) encompasses the spectrum of gastric mucosal injury ranging from superficial erosions (stress gastritis) to deep ulcers (stress ulcers) occurring in the context of critical illness. [9,21]

Clinically Important Gastrointestinal Bleeding is defined as overt GI bleeding (hematemesis, melena, bloody nasogastric aspirate, hematochezia) with one of the following within 24 hours: [4,22]

• Hemodynamic compromise (MAP <65 mmHg, vasopressor increase >20%, HR increase >20 bpm)
• Decrease in hemoglobin ≥2 g/dL requiring transfusion
• Need for endoscopic or surgical intervention

Overt GI Bleeding: Visible bleeding (coffee-ground aspirate, melena, hematemesis) without hemodynamic or laboratory changes.

Epidemiology

Historical Context:

• Before routine SUP (1970s-1980s), clinically significant GI bleeding occurred in 15-25% of ICU patients [1]
• Early prophylaxis studies (1990s) reported bleeding rates of 5-10% [23]
• Modern ICU care (2010s-present) reports bleeding rates of 1-4% even without prophylaxis [4,5]

Current Incidence (2020s Data):

Sources: SUP-ICU trial, PEPTIC trial, systematic reviews [4,5,24]

Australian/NZ Data (ANZICS CORE):

• ANZICS Adult Patient Database shows clinically important GI bleeding rate of approximately 1-2% in Australian/NZ ICUs [25]
• Local practice varies; many units have adopted selective SUP based on risk stratification
• Remote/rural ICUs may have limited access to endoscopy; lower threshold for prophylaxis

Mortality Associated with GI Bleeding:

• Clinically significant GI bleeding associated with ICU mortality of 40-50% [3,26]
• However, causation vs association unclear (bleeding may be marker of severity)
• SUP-ICU trial: No mortality reduction with prophylaxis despite reduced bleeding

Cost Considerations:

• PPI (pantoprazole 40 mg IV): AU$2-5 per day
• H2RA (famotidine 20 mg IV): AU$1-3 per day
• Cost of GI bleeding episode (transfusion, endoscopy, ICU stay): AU$10,000-50,000 [27]
• NNT to prevent one bleeding episode: 30-60 (based on SUP-ICU)

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2. Applied Basic Sciences

2.1 Gastric Physiology

This section integrates CICM First Part basic science with Second Part clinical application

Normal Gastric Acid Secretion:

Gastric acid is produced by parietal cells in the gastric fundus and body via the H+/K+-ATPase (proton pump) on the apical membrane. [28]

Regulation of Acid Secretion:

1. Stimulatory Pathways:

   • Acetylcholine (ACh): Vagal stimulation via muscarinic M3 receptors
   • Gastrin: Released from G cells in response to food, stimulates parietal cells and enterochromaffin-like (ECL) cells
   • Histamine: Released from ECL cells, binds H2 receptors on parietal cells (primary final common pathway)

2. Inhibitory Pathways:

   • Somatostatin: Released from D cells, inhibits gastrin and histamine release
   • Prostaglandins (PGE2): Inhibit acid secretion, stimulate bicarbonate and mucus secretion
   • Secretin: Released from duodenal S cells in response to acid

The Proton Pump (H+/K+-ATPase):

• Located on the apical (luminal) membrane of parietal cells
• Actively transports H+ into the gastric lumen in exchange for K+
• Final common pathway for all acid secretion
• PPIs irreversibly inhibit this pump

Gastric Mucosal Defense Mechanisms:

The gastric mucosa has multiple layers of protection against acid injury: [29]

1. Pre-epithelial Barrier:

   • Mucus layer (unstirred layer) - traps bicarbonate
   • Bicarbonate secretion (HCO3-) - neutralizes acid at mucosal surface
   • Surface phospholipids - hydrophobic barrier

2. Epithelial Barrier:

   • Tight junctions between epithelial cells
   • Rapid cell turnover (every 3-5 days)
   • Ion transporters maintain intracellular pH

3. Post-epithelial Barrier:

   • Mucosal blood flow (delivers oxygen, removes H+)
   • Prostaglandins (maintain blood flow, stimulate mucus/bicarbonate)
   • Sensory afferent nerves (capsaicin-sensitive)

2.2 Pathophysiology of Stress-Related Mucosal Disease

Stress Ulcer vs Peptic Ulcer Disease:

Pathophysiology of SRMD [9,21,30]:

1. Splanchnic Hypoperfusion:

• Critical illness (sepsis, shock, trauma) → redistribution of blood flow away from GI tract
• Splanchnic blood flow reduced by 50-70% in severe shock [31]
• Mucosal ischemia → loss of post-epithelial barrier function

2. Ischemia-Reperfusion Injury:

• Restoration of blood flow generates reactive oxygen species (ROS)
• ROS damage epithelial cells, tight junctions
• Exacerbates mucosal injury during resuscitation

3. Loss of Protective Mechanisms:

• Prostaglandin depletion: Stress, NSAIDs, and ischemia reduce PGE2 synthesis
• Reduced bicarbonate secretion: Impaired epithelial function
• Mucus depletion: Ischemia reduces mucus production

4. Acid Back-Diffusion:

• Damaged mucosa allows H+ ions to diffuse back into tissue
• Leads to submucosal edema, hemorrhage, necrosis
• Creates a vicious cycle of injury

5. Inflammatory Mediators:

• Systemic inflammatory response (SIRS) in critical illness
• TNF-α, IL-1β, IL-6 exacerbate mucosal injury
• Neutrophil infiltration and oxidative damage

6. Impaired Mucosal Repair:

• Critical illness impairs epithelial regeneration
• Malnutrition reduces protein synthesis for cell turnover
• Growth factor signaling disrupted

Timeline of SRMD Development [32]:

• 0-24 hours: Superficial erosions in 75-100% of ICU patients
• 24-72 hours: Deeper erosions, submucosal hemorrhage
• 3-7 days: Peak risk of clinically significant bleeding
• >7 days: Risk decreases with recovery, resumption of nutrition

2.3 Pharmacology

Proton Pump Inhibitors (PPIs)

Mechanism of Action [28,33]:

• Irreversible inhibition of H+/K+-ATPase (proton pump) on parietal cell apical membrane
• PPIs are prodrugs activated in the acidic environment of parietal cell canaliculus
• Activated drug forms covalent disulfide bond with cysteine residues on the pump
• Effect lasts until new pumps are synthesized (half-life of pump: 50 hours)
• Onset of maximal effect: 2-5 days (need to inhibit newly synthesized pumps)

Pharmacokinetics:

ICU-Specific Considerations:

• IV formulation preferred in patients with GI dysfunction
• Continuous infusion offers no advantage over once-daily dosing for prophylaxis [34]
• Absorption of oral PPIs may be impaired in critically ill (gastroparesis, altered pH)

Drug Interactions [18,35]:

Adverse Effects [7,14,36]:

• C. difficile infection: OR 1.3-2.0; reduced gastric acid allows spore survival
• Hospital-acquired pneumonia: OR 1.2-1.5 (controversial); gastric colonization with pathogens
• Hypomagnesemia: Chronic use (>3 months); check Mg2+ if on PPIs >1 week
• Fracture risk: Chronic use; reduced calcium absorption
• Vitamin B12 deficiency: Chronic use; reduced absorption
• Acute interstitial nephritis: Rare but serious

PBS (Australian) Considerations:

• Pantoprazole, omeprazole, esomeprazole available on PBS
• IV pantoprazole commonly used in ICU; hospital formulary variations
• No PBS restriction for inpatient use

Histamine-2 Receptor Antagonists (H2RAs)

Mechanism of Action [10,37]:

• Competitive, reversible inhibition of H2 receptors on parietal cells
• H2 receptor blockade reduces histamine-stimulated acid secretion
• Does not block acetylcholine or gastrin pathways directly
• Effect on acid secretion: 50-70% reduction (vs 80-95% with PPIs)

Pharmacokinetics:

*Ranitidine withdrawn from market in 2020 due to NDMA contamination [38] **Cimetidine rarely used due to drug interactions

Tachyphylaxis [10,11]:

• H2RA effect diminishes by 50% within 48-72 hours of continuous use
• Mechanism: Upregulation of H2 receptors, alternative acid secretion pathways
• Clinical significance: May reduce long-term efficacy for SUP
• PPIs do not exhibit tachyphylaxis (irreversible binding to new pumps)

Adverse Effects:

• Generally well-tolerated
• Thrombocytopenia: Rare (more common with ranitidine)
• Mental status changes: Especially in elderly, renal impairment
• Drug interactions (cimetidine): CYP450 inhibition (warfarin, theophylline, phenytoin)
• C. difficile/pneumonia risk: Similar to PPIs (per PEPTIC trial) [5]

Australian Context:

• Famotidine is the primary H2RA available since ranitidine withdrawal
• IV famotidine available but less commonly used than IV pantoprazole
• Oral famotidine can be crushed for NG administration

Sucralfate

Mechanism of Action [39]:

• Aluminum hydroxide salt of sulfated sucrose
• Forms protective barrier over ulcerated/damaged mucosa
• Binds to positite charges on proteins in ulcer base
• Stimulates prostaglandin synthesis, mucus secretion
• Does not suppress acid secretion

Pharmacokinetics:

• Minimal systemic absorption (<5%)
• Requires acidic pH for activation (less effective with concurrent antacids/PPIs)
• Dose: 1 g PO/NG q6h

Evidence in ICU [40,41]:

• Inferior to H2RAs and PPIs for preventing GI bleeding
• No increased risk of C. difficile or pneumonia (no acid suppression)
• Limited use in modern ICU practice

Disadvantages:

• Drug interactions: Reduces absorption of phenytoin, fluoroquinolones, warfarin
• Aluminum toxicity risk in renal failure
• Bezoar formation with prolonged use
• Requires multiple daily doses

Comparison Table: PPI vs H2RA vs Sucralfate

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3. Risk Factors and Indications

Classic Risk Factors (Cook 1994)

The landmark prospective cohort study by Cook et al. (1994) identified risk factors for clinically important GI bleeding in 2,252 ICU patients: [3]

Independent Risk Factors (Multivariate Analysis):

Other Associated Factors (Univariate Only):

• Renal failure (RRT)
• Hepatic failure
• Sepsis
• Hypotension (MAP <70 mmHg for >2 hours)
• High-dose corticosteroids
• Burns >35% TBSA
• Organ transplantation
• Head injury (Cushing's ulcer)
• Spinal cord injury

Interpretation for Modern Practice:

• Mechanical ventilation >48 hours AND coagulopathy: Highest risk (bleeding rate 8-12%)
• One risk factor only: Moderate risk (bleeding rate 2-4%)
• No risk factors: Low risk (bleeding rate <1%) [4]

Current Indications for SUP

High-Risk Patients (SUP Recommended) [6,22,42]:

1. Mechanical ventilation expected >48 hours - Most common indication
2. Coagulopathy:
   • Platelet count <50 × 10⁹/L
   • INR >1.5
   • Therapeutic anticoagulation
3. Both MV >48h AND coagulopathy - Highest risk; SUP strongly indicated
4. Severe burns (>35% TBSA) - Curling's ulcer
5. Traumatic brain injury - Cushing's ulcer
6. Spinal cord injury
7. Multiple trauma (ISS >16)
8. Hepatic failure with coagulopathy
9. Septic shock requiring high-dose vasopressors
10. History of GI bleeding in past year
11. High-dose corticosteroids with NSAID/antiplatelet use

Low-Risk Patients (SUP May Be Omitted) [4,5,43]:

1. Receiving enteral nutrition - Mucosal protection may be adequate
2. Short-term mechanical ventilation (<48 hours)
3. No coagulopathy
4. Hemodynamically stable, low illness severity (APACHE II <15)
5. Post-operative patients without other risk factors

ANZICS/Australian Recommendations

ANZICS Position [20,25]:

• No formal ANZICS-CORE statement mandating universal SUP
• Recommends individualized approach based on risk stratification
• Enteral nutrition considered part of the prophylaxis strategy
• Encourages de-escalation when risk factors resolve

eTG Complete (Therapeutic Guidelines Australia):

• SUP recommended in patients with MV >48h and/or coagulopathy
• PPI or H2RA acceptable; PPIs marginally more effective for bleeding prevention
• Duration: Continue until extubation, coagulopathy resolves, and/or full EN established
• Consider risks of C. difficile and pneumonia in risk-benefit analysis

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4. Evidence Summary

4.1 Landmark Trials

SUP-ICU Trial (2018) [4]

Citation: Krag M, Marker S, Perner A, et al. Pantoprazole in Patients at Risk for Gastrointestinal Bleeding in the ICU. N Engl J Med. 2018;379(23):2199-2208. PMID: 30141781

Design:

• Type: Multicenter, randomized, blinded, placebo-controlled trial
• Setting: 33 ICUs in 6 European countries
• Population: 3,298 adult ICU patients at risk for GI bleeding
• Risk criteria: At least one of:
  • Shock (vasopressors and/or lactate >4 mmol/L)
  • RRT
  • Therapeutic anticoagulation
  • Coagulopathy
  • Chronic liver disease
• Exclusion: Current GI bleeding, PPI/H2RA use on admission, pregnancy

Intervention:

• Pantoprazole 40 mg IV once daily vs placebo
• Duration: Until ICU discharge, oral intake, or 90 days

Primary Outcome:

• 90-day all-cause mortality

Key Results:

NNT for Clinically Important Bleeding: 59 (95% CI: 31-500)

Interpretation:

• Pantoprazole reduced clinically important GI bleeding but did not reduce mortality
• Low absolute risk of bleeding even in "at-risk" population (placebo group 4.2%)
• No significant increase in adverse events (C. diff, pneumonia)
• Calls into question the benefit of universal SUP

Limitations:

• Did not include patients with MV >48h as sole risk factor (Cook's criterion)
• Excluded patients already on PPIs (selection bias)
• Underpowered for mortality (designed for bleeding endpoint)
• European population; may not be generalizable

Clinical Implications:

• Consider omitting SUP in low-risk patients
• If used, pantoprazole 40 mg IV daily is appropriate
• Benefits modest; must weigh against potential adverse effects

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PEPTIC Trial (2020) [5]

Citation: Young PJ, Bagshaw SM, Forbes AB, et al. Effect of Stress Ulcer Prophylaxis With Proton Pump Inhibitors vs Histamine-2 Receptor Blockers on In-Hospital Mortality Among ICU Patients Receiving Invasive Mechanical Ventilation: The PEPTIC Randomized Clinical Trial. JAMA. 2020;323(6):616-626. PMID: 31950977

Design:

• Type: Pragmatic, cluster-randomized, crossover, registry-embedded trial
• Setting: 50 ICUs in 5 countries (Australia, New Zealand, UK, Canada, Ireland)
• Population: 26,828 adults receiving invasive mechanical ventilation
• Intervention: ICU-level randomization to PPI-first or H2RA-first strategy
• Crossover: Each ICU used assigned drug for 6 months, then switched

Medications Used:

• PPIs: Pantoprazole, omeprazole, esomeprazole, lansoprazole (any)
• H2RAs: Famotidine, ranitidine (pre-withdrawal)
• At physician discretion: Could use alternative agent if indicated

Primary Outcome:

• In-hospital mortality up to 90 days

Key Results:

Interpretation:

• No significant mortality difference between PPIs and H2RAs
• Borderline trend toward higher mortality with PPIs (p=0.054)
• PPIs superior for preventing clinically significant GI bleeding (NNT = 200)
• No difference in C. difficile infection rates
• Very low bleeding rates in both groups (reflecting modern ICU care)

Limitations:

• Pragmatic design; open-label at ICU level
• Crossover between agents allowed in some patients
• Cannot determine optimal duration or whether SUP beneficial overall
• Ranitidine used (now withdrawn); famotidine may have different profile

Clinical Implications:

• Either PPIs or H2RAs acceptable for SUP
• PPIs marginally better at preventing bleeding
• Borderline mortality signal with PPIs warrants ongoing vigilance
• Decision should incorporate local factors (formulary, cost, drug interactions)

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Other Key Trials and Meta-Analyses

Cook et al. 1998 (Comparison Trial) [44] - PMID: 9480442

• 1,200 ICU patients: Ranitidine 50 mg IV q8h vs sucralfate 1 g q6h
• Clinically important bleeding: 1.7% (ranitidine) vs 3.8% (sucralfate), p=0.02
• No mortality difference
• Established H2RAs as superior to sucralfate

Alhazzani et al. 2017 (Cochrane Review) [24] - PMID: 28568465

• 12,660 patients from 80 trials
• PPIs vs H2RAs: PPIs reduced clinically important bleeding (RR 0.53, 95% CI 0.41-0.70)
• PPIs vs placebo: RR 0.42 (95% CI 0.29-0.63) for overt bleeding
• No mortality difference in any comparison
• Moderate-quality evidence; heterogeneous trials

Wang et al. 2020 (Meta-Analysis) [45] - PMID: 31908133

• 72,846 patients from 57 trials
• Network meta-analysis: PPIs most effective for bleeding prevention
• No difference in mortality between PPIs, H2RAs, placebo
• C. difficile: PPIs OR 1.25 (95% CI 0.86-1.82) - non-significant increase

4.2 Interpretation and Limitations

Summary of Evidence:

1. SUP reduces GI bleeding - Consistent across trials; NNT 30-60 for high-risk patients
2. No mortality benefit - Neither SUP-ICU nor PEPTIC showed mortality reduction
3. Modern bleeding rates are low - 1-4% even without prophylaxis (vs 15-20% historically)
4. PPIs vs H2RAs - PPIs marginally more effective; no clear mortality difference
5. Adverse effects - C. difficile and pneumonia risk present but modest

Why Has GI Bleeding Decreased? [46,47]

Changes in ICU practice that may explain reduced bleeding rates:

1. Earlier and more aggressive resuscitation - Better splanchnic perfusion
2. Goal-directed fluid therapy - Less mucosal ischemia
3. Lower use of high-dose steroids - Reduced mucosal injury
4. Early enteral nutrition - Mucosal protection, prostaglandin maintenance
5. Improved ventilator care - Shorter MV duration
6. Lower severity of illness due to ICU outreach - Earlier intervention

Unanswered Questions:

1. Is SUP needed in patients receiving enteral nutrition?
2. What is the optimal duration of SUP?
3. Are PPIs associated with increased mortality in specific subgroups?
4. Should SUP be used in low-risk patients at all?

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5. ICU Management

5.1 Agent Selection

PPI vs H2RA Decision Framework:

Favor PPIs (Pantoprazole 40 mg IV/PO daily):

• High-risk patients (MV + coagulopathy)
• History of peptic ulcer disease or GI bleeding
• Concurrent NSAID or antiplatelet therapy
• Hepatic failure (coagulopathy, varices risk)
• Burns, TBI, spinal cord injury

Favor H2RAs (Famotidine 20 mg IV/PO BD):

• Concern for PPI drug interactions (clopidogrel, tacrolimus)
• Previous C. difficile infection
• Moderate-risk patients
• Shorter ICU stay anticipated (<5 days)
• If tachyphylaxis acceptable (short-term use)

Neither (No Routine SUP):

• Receiving enteral nutrition with no other risk factors
• Short-term MV (<48 hours)
• Low illness severity (APACHE II <10)
• No coagulopathy

5.2 Dosing and Administration

Proton Pump Inhibitors:

Notes:

• IV route preferred in critically ill with GI dysfunction
• Convert to PO/NG when tolerating enteral nutrition
• No continuous infusion needed for prophylaxis (vs treatment of active bleeding)
• Give 30-60 minutes before meal/feed if possible (optimizes absorption)

Histamine-2 Receptor Antagonists:

*Cimetidine rarely used due to drug interactions

Notes:

• More frequent dosing than PPIs
• Renal dose adjustment required
• Tachyphylaxis occurs after 48-72 hours
• Consider switching to PPI if prolonged ICU stay

5.3 Duration

Standard Duration Guidelines [6,19]:

1. Continue SUP until:

   • Extubation from mechanical ventilation
   • Resolution of coagulopathy (platelets >50, INR <1.5)
   • Established full enteral nutrition for >48-72 hours
   • ICU discharge to ward
   • Oral intake resumed

2. Do NOT continue indefinitely:

   • Inappropriate continuation at hospital discharge is common (30-50%)
   • Hospital-wide stewardship programs reduce inappropriate prescribing
   • Outpatient PPI use associated with adverse effects (see below)

5.4 De-escalation and Discontinuation

Hospital Stewardship Approach [19,48]:

1. Daily Review: During ICU rounds, assess ongoing need for SUP
2. Ward Transfer: Automatic stop order unless active indication
3. Discharge Reconciliation: Remove SUP from discharge medications unless pre-existing indication

Indications to Continue SUP Beyond ICU:

• Pre-existing indication (GERD, Barrett's, peptic ulcer disease)
• Therapeutic anticoagulation with high bleeding risk
• Ongoing need for high-dose steroids + NSAID
• Active GI bleeding requiring treatment (not prophylaxis)

Transition from IV to PO:

• When tolerating enteral nutrition, switch IV to PO/NG
• PPI efficacy similar by both routes
• Reduces cost and line-related complications

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6. Adverse Effects

Clostridioides difficile Infection (CDI)

Epidemiology [14,15,49]:

• CDI affects 4-10% of ICU patients
• Acid suppression reduces gastric barrier to C. difficile spores
• PPIs associated with OR 1.3-2.0 for CDI (observational studies)
• PEPTIC trial: No significant difference (PPI 0.30% vs H2RA 0.43%)

Mechanism:

• C. difficile spores acid-resistant but vegetative forms killed by pH <4.5
• Gastric acid suppression allows spore survival and germination in colon
• Altered gut microbiome (antibiotics) exacerbates risk

Clinical Implications:

• Consider CDI in ICU patient with new diarrhea on PPI/H2RA
• Test with stool PCR or toxin assay
• If CDI confirmed: Isolate, contact precautions, oral vancomycin 125 mg QID or fidaxomicin 200 mg BD
• Consider discontinuing acid suppression if no longer indicated

Hospital-Acquired Pneumonia (HAP) and VAP

Evidence [16,17,50]:

• Gastric colonization with pathogens increases with acid suppression
• Retrograde aspiration of colonized gastric contents may cause pneumonia
• Meta-analyses: PPIs/H2RAs associated with OR 1.2-1.5 for HAP/VAP
• SUP-ICU and PEPTIC trials: No significant difference in pneumonia rates

Proposed Mechanisms:

• Alkaline gastric pH allows bacterial overgrowth (E. coli, Pseudomonas, Klebsiella)
• Aspiration of colonized secretions
• Biofilm formation on nasogastric tubes

Mitigation Strategies:

• Elevate head of bed to 30-45°
• Oral care with chlorhexidine
• Subglottic suctioning ETT
• Limit duration of acid suppression

Drug Interactions (PPIs)

Clinically Significant Interactions [18,35]:

PPI Selection to Minimize Interactions:

• Pantoprazole: Lowest CYP2C19 inhibition; preferred when interactions concern
• Omeprazole: Highest CYP2C19 inhibition; avoid with clopidogrel if possible
• Esomeprazole: Moderate CYP2C19 inhibition

Hypomagnesemia

Mechanism [51,52]:

• PPIs reduce intestinal magnesium absorption (TRPM6/7 channel impairment)
• Usually occurs with prolonged use (>3 months)
• Can occur within 1 week in critically ill with marginal stores

Clinical Significance:

• Hypomagnesemia causes arrhythmias, muscle weakness, seizures
• ICU patients often have multiple reasons for low Mg2+ (RRT, diarrhea, drugs)
• Monitor Mg2+ if on PPIs >1 week

Management:

• Check Mg2+ weekly if on prolonged PPI
• Replace IV/PO magnesium as needed
• Consider H2RA or discontinuing acid suppression if severe recurrent hypomagnesemia

Other Long-Term Effects (Less Relevant to ICU)

• Osteoporosis/Fracture Risk: Chronic use; reduced calcium absorption
• Vitamin B12 Deficiency: Chronic use; reduced intrinsic factor activation
• Acute Interstitial Nephritis: Rare; monitor renal function
• Microscopic Colitis: Rare; consider if persistent diarrhea
• Dementia Association: Observational only; likely confounding

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7. Monitoring

Clinical Monitoring for GI Bleeding

Signs of GI Bleeding to Monitor [53]:

1. Direct Evidence:

   • Hematemesis (coffee-ground or fresh blood vomitus)
   • Melena (black, tarry stool)
   • Bloody nasogastric aspirate
   • Hematochezia (usually lower GI, but massive upper GI can cause)

2. Indirect Evidence:

   • Unexplained drop in hemoglobin (≥2 g/dL)
   • Unexplained hypotension or tachycardia
   • Increasing vasopressor requirements without other cause
   • Rising lactate without other explanation
   • Decreased urine output (hypovolemia)

3. High-Risk Periods:

   • Days 3-7 of ICU stay (peak SRMD risk)
   • During anticoagulation escalation
   • Peri-procedural (surgery, endoscopy, bronchoscopy)

Laboratory Monitoring

Routine Monitoring:

• Hemoglobin: Daily (detect occult bleeding)
• Platelet count: Daily (coagulopathy assessment)
• Coagulation studies (INR, APTT): Daily or as indicated
• Magnesium: Weekly if on PPI >1 week
• Stool for C. difficile: If new diarrhea (>3 loose stools/day)

Not Recommended:

• Routine gastric residual volume (NUTRIREA-2 evidence)
• Fecal occult blood testing (low sensitivity for SRMD)
• Routine endoscopy for surveillance

Response to GI Bleeding

If Clinically Significant GI Bleeding Occurs:

1. Resuscitate (A-E approach):

   • Airway: Consider intubation if active hematemesis and reduced GCS
   • Breathing: High-flow oxygen
   • Circulation: Two large-bore IV cannulae, crystalloid bolus, crossmatch blood
   • Transfusion: Target Hb 70-90 g/L (restrictive strategy); 70-80 g/L in most; higher if massive bleeding or cardiac disease

2. Reverse Coagulopathy:

   • Platelets if <50 × 10⁹/L and active bleeding
   • FFP/PCC if INR >1.5 and active bleeding
   • Vitamin K 10 mg IV if warfarin-related
   • Hold therapeutic anticoagulation (discuss with treating team)

3. Optimize Acid Suppression:

   • Convert to high-dose PPI: Pantoprazole 80 mg IV bolus, then 8 mg/hour infusion
   • Continue until endoscopy or bleeding controlled

4. Gastroenterology Consultation:

   • Urgent endoscopy within 24 hours for most
   • Emergent endoscopy if hemodynamically unstable despite resuscitation
   • Interventional radiology if endoscopy fails

5. Prokinetics:

   • Erythromycin 250 mg IV 30-60 min before endoscopy (improves visualization)

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8. Special Populations

8.1 Enteral Nutrition - Does EN Provide Prophylaxis?

Evidence for EN as Mucosal Protection [12,13,54]:

Physiological Rationale:

• Luminal nutrients maintain mucosal blood flow
• Enteral feeding stimulates prostaglandin synthesis (cytoprotective)
• Prevention of mucosal atrophy (maintains epithelial barrier)
• Buffering of gastric acid by feed (pH rises to 5-6)

Clinical Evidence:

• Observational Studies: Patients receiving EN have lower GI bleeding rates than those nil-by-mouth or on PN [55]
• Pinilla et al. 2001: EN alone vs EN + SUP - no difference in bleeding (0% in both groups in small study) [56]
• No RCTs directly comparing EN alone vs SUP

Current Guidelines:

• ESPEN 2019: EN may provide adequate mucosal protection in low-risk patients; SUP may be omitted if receiving EN and no other risk factors [6]
• ASPEN/SCCM 2016: SUP recommended regardless of EN in high-risk patients [22]
• ANZICS: Consider EN as part of prophylaxis strategy; individualize [20]

Practical Approach:

• High-risk (MV >48h + coagulopathy): SUP + EN
• Moderate-risk (MV only): EN may be sufficient; consider omitting pharmacological SUP
• Low-risk (no MV, no coagulopathy, receiving EN): No SUP required

8.2 Coagulopathy

Increased Bleeding Risk [3,57]:

• Coagulopathy (platelets <50, INR >1.5, therapeutic anticoagulation) is independent risk factor (OR 4.3)
• Combined with MV >48 h: Bleeding rate 8-12%
• SUP strongly recommended in this population

Special Considerations:

• ECMO patients: Anticoagulation + critical illness = very high risk; SUP recommended
• Therapeutic anticoagulation (heparin, warfarin, DOACs): SUP recommended
• Liver failure with coagulopathy: SUP recommended; PPIs safe in hepatic impairment
• Thrombocytopenia: Transfuse if <50 with active bleeding; SUP reduces need for transfusion

Management:

• Continue SUP until coagulopathy resolves
• If bleeding occurs: Reverse coagulopathy + high-dose PPI + endoscopy

8.3 Neurocritical Care

Cushing's Ulcer (TBI) [58,59]:

• Severe TBI associated with gastric hypersecretion (vagal stimulation)
• Gastric pH lower in TBI patients (pH 2-3 vs 4-5 in other ICU patients)
• High bleeding risk: GI bleeding in 5-10% of severe TBI
• SUP strongly recommended in TBI

Spinal Cord Injury [60]:

• Autonomic dysfunction affects GI motility and acid secretion
• High bleeding risk, especially in cervical/high thoracic injuries
• SUP recommended for at least 4 weeks post-injury

Subarachnoid Hemorrhage:

• Stress response, high catecholamines, often on antiplatelet agents
• SUP recommended during acute phase

Specific Recommendations:

• PPIs preferred (more potent acid suppression)
• Continue SUP until neurological stability, able to protect airway, oral intake

8.4 Indigenous Health Considerations

Aboriginal and Torres Strait Islander Peoples [61,62]:

• Higher rates of peptic ulcer disease, H. pylori infection, GI malignancy
• Higher rates of alcohol-related liver disease (coagulopathy)
• Diabetes and CKD may delay gastric emptying (gastroparesis)
• May present later with more severe critical illness

Clinical Implications:

• Lower threshold for SUP in Indigenous patients with multiple risk factors
• Consider H. pylori testing if history of peptic ulcer disease
• Family/community involvement in treatment decisions
• Aboriginal Health Workers (AHWs) and Aboriginal Liaison Officers (ALOs) can facilitate communication

Māori Health (New Zealand) [63]:

• Higher rates of diabetes, CKD, and liver disease
• Similar considerations re: family involvement (whānau-centered care)
• Māori Health Workers to support communication

Remote/Rural Considerations:

• Limited access to endoscopy; may require retrieval to tertiary center
• Lower threshold for SUP if endoscopy not locally available
• Telemedicine consultation for GI bleeding management
• RFDS retrieval for hemodynamically unstable GI bleed

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9. Progressive Clinical Assessments

Basic Level (Foundation Knowledge)

Target: Medical students, junior doctors, early ICU trainees

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Question 1: Definition

Q: Define stress ulcer prophylaxis and explain why it is used in the ICU.

A: Stress ulcer prophylaxis (SUP) is the pharmacological prevention of stress-related mucosal disease (SRMD) and clinically significant upper gastrointestinal bleeding in critically ill patients.

It is used in ICU because:

1. Critical illness causes splanchnic hypoperfusion and mucosal ischemia
2. Loss of protective mechanisms (mucus, bicarbonate, prostaglandins)
3. Historical bleeding rates of 15-20% in ICU (now 1-4% with modern care)
4. GI bleeding associated with increased mortality (40-50%)
5. High-risk patients (MV >48h, coagulopathy) benefit from prophylaxis

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Question 2: Risk Factors

Q: List 5 risk factors for stress ulcer bleeding in ICU patients.

A:

1. Mechanical ventilation >48 hours (OR 15.6 - strongest risk factor)
2. Coagulopathy (platelets <50, INR >1.5, therapeutic anticoagulation; OR 4.3)
3. Severe burns (>35% TBSA - Curling's ulcer)
4. Traumatic brain injury (Cushing's ulcer - vagal stimulation)
5. Septic shock requiring high-dose vasopressors
6. (Also: spinal cord injury, hepatic failure, renal failure, history of GI bleeding)

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Question 3: Agents

Q: Name the two main drug classes used for SUP and give one example of each.

A:

1. Proton Pump Inhibitors (PPIs): Examples - pantoprazole, omeprazole, esomeprazole
2. Histamine-2 Receptor Antagonists (H2RAs): Examples - famotidine, cimetidine (ranitidine withdrawn)

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Question 4: Mechanism

Q: Explain the mechanism of action of proton pump inhibitors.

A: PPIs irreversibly inhibit the H+/K+-ATPase (proton pump) on the apical membrane of gastric parietal cells.

Key points:

• PPIs are prodrugs activated in the acidic canaliculus of parietal cells
• Activated drug forms covalent disulfide bond with cysteine residues on the pump
• This irreversibly inactivates the pump
• Effect lasts until new pumps are synthesized (pump half-life ~50 hours)
• Results in 80-95% reduction in gastric acid secretion

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Intermediate Level (Applied Knowledge)

Target: ICU registrars, mid-training

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Question 1: Evidence Interpretation

Stem: You are presenting at journal club and have been asked to summarize the SUP-ICU trial for your colleagues.

Q1: Describe the design and primary outcome of the SUP-ICU trial. (4 marks)

A1: Design (2 marks):

• Multicenter, randomized, double-blind, placebo-controlled trial
• 3,298 adult ICU patients at risk for GI bleeding (33 ICUs, 6 European countries)
• Intervention: Pantoprazole 40 mg IV daily vs placebo
• Duration: Until ICU discharge, oral intake, or 90 days

Primary Outcome (2 marks):

• 90-day all-cause mortality
• Result: 31.1% (pantoprazole) vs 30.4% (placebo) - no significant difference (p=0.76)

Q2: What were the secondary outcomes related to GI bleeding, and what is the NNT? (3 marks)

A2: Secondary Outcomes (2 marks):

• Clinically important GI bleeding: 2.5% (pantoprazole) vs 4.2% (placebo), p=0.04
• Overt GI bleeding: 4.8% vs 7.8%, p<0.001

NNT (1 mark):

• NNT for clinically important bleeding: 59 (95% CI 31-500)
• Interpretation: Need to treat 59 patients to prevent 1 bleeding episode

Q3: What are the clinical implications of this trial? (3 marks)

A3:

1. Modest benefit: SUP reduces bleeding but does not reduce mortality
2. Low event rates: Even placebo group had low bleeding rate (4.2%)
3. Risk-benefit balance: Benefits must be weighed against potential adverse effects (C. diff, pneumonia)
4. Selective use: Consider omitting SUP in low-risk patients; reserve for high-risk (MV + coagulopathy)
5. If using: Pantoprazole 40 mg IV daily is appropriate dose

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Question 2: Drug Comparison

Q: Compare PPIs and H2RAs for stress ulcer prophylaxis. Include mechanism, efficacy, and adverse effects.

A:

Clinical Implication: PPIs marginally more effective for bleeding prevention; either acceptable. Choose based on drug interactions, renal function, and local formulary.

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Question 3: Case Scenario

Stem: A 62-year-old man with COPD is admitted to ICU with community-acquired pneumonia requiring intubation. He has been mechanically ventilated for 72 hours. His platelet count is 85 × 10⁹/L and INR is 1.8 due to hepatic congestion. He is on continuous enteral nutrition via NG tube at 60 mL/h.

Q: Should this patient receive stress ulcer prophylaxis? Justify your answer. (5 marks)

A: Yes, this patient should receive SUP (1 mark)

Justification (4 marks):

1. High-risk patient:

   • Mechanical ventilation >48 hours (72h) - OR 15.6
   • Coagulopathy (platelets 85, INR 1.8) - OR 4.3
   • Combined risk factors = highest risk group (bleeding rate 8-12%)

2. Despite enteral nutrition:

   • EN provides some mucosal protection
   • However, with two major risk factors, pharmacological SUP is recommended
   • EN + SUP is the appropriate strategy for high-risk patients

3. Agent selection:

   • PPI (pantoprazole 40 mg IV daily) preferred
   • More potent acid suppression in high-risk patient
   • Can convert to NG administration if tolerating EN well

4. Duration:

   • Continue until: extubation, INR normalizes, platelet count recovers
   • Do not continue indefinitely beyond ICU stay

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Exam Level (CICM Second Part Standard)

Target: Final year trainees, exam candidates

Full exam-level questions are in Section 10 (SAQ Practice)

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10. SAQ Practice (2 Questions)

SAQ 1: Evidence-Based Stress Ulcer Prophylaxis

Time Allocation: 10 minutes
Total Marks: 20

Stem: A 58-year-old woman is admitted to ICU following emergency laparotomy for perforated diverticulitis. She is intubated and mechanically ventilated, receiving noradrenaline at 0.15 mcg/kg/min, and has a platelet count of 145 × 10⁹/L with INR 1.2. Enteral nutrition via nasojejunal tube has been commenced at 20 mL/h and is being advanced.

The ICU registrar asks whether stress ulcer prophylaxis should be commenced.

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Question 1.1 (8 marks)

Outline the pathophysiology of stress-related mucosal disease in critically ill patients and list the independent risk factors for clinically important gastrointestinal bleeding.

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Question 1.2 (6 marks)

Describe the key findings of the SUP-ICU and PEPTIC trials that inform your decision about stress ulcer prophylaxis in this patient.

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Question 1.3 (6 marks)

Based on the evidence, what is your recommendation for this patient? Include your choice of agent, dose, route, and criteria for discontinuation.

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Model Answer

Question 1.1 (8 marks total)

Pathophysiology of SRMD (4 marks):

1. Splanchnic hypoperfusion (1 mark):

   • Critical illness redistributes blood flow away from GI tract
   • Shock reduces splanchnic blood flow by 50-70%
   • Mucosal ischemia impairs epithelial barrier function

2. Ischemia-reperfusion injury (1 mark):

   • Resuscitation generates reactive oxygen species (ROS)
   • Oxidative damage to epithelial cells and tight junctions

3. Loss of protective mechanisms (1 mark):

   • Reduced prostaglandin synthesis (PGE2)
   • Impaired mucus and bicarbonate secretion
   • Epithelial cell death and delayed regeneration

4. Acid back-diffusion (1 mark):

   • Damaged mucosa allows H+ ions to diffuse into tissue
   • Causes submucosal edema, hemorrhage, necrosis
   • Creates vicious cycle of injury

Independent Risk Factors (Cook 1994) (4 marks - 2 marks each):

Additional factors (univariate): Renal failure, hepatic failure, sepsis, burns >35% TBSA, TBI, spinal cord injury, high-dose steroids

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Question 1.2 (6 marks total)

SUP-ICU Trial (2018) (3 marks):

• Design: Multicenter RCT; 3,298 ICU patients at risk for GI bleeding; pantoprazole 40 mg IV daily vs placebo

• Primary Outcome (1 mark): 90-day mortality - no difference (31.1% vs 30.4%, p=0.76)

• Secondary Outcomes (1 mark):

  • "Clinically important GI bleeding: 2.5% (PPI) vs 4.2% (placebo), p=0.04"
  • NNT = 59

• Interpretation (1 mark): SUP reduces bleeding but not mortality; low absolute bleeding risk even without prophylaxis; consider omitting in low-risk patients

PEPTIC Trial (2020) (3 marks):

• Design: Cluster-randomized trial; 26,828 mechanically ventilated patients; PPI vs H2RA strategy

• Primary Outcome (1 mark): 90-day mortality - no significant difference (18.3% PPI vs 17.5% H2RA, p=0.054 - borderline)

• Secondary Outcome (1 mark):

  • "Clinically significant GI bleeding: 1.3% (PPI) vs 1.8% (H2RA), p<0.05"
  • "C. difficile: No significant difference"

• Interpretation (1 mark): Either PPI or H2RA acceptable; PPIs marginally better at preventing bleeding; borderline trend toward higher mortality with PPIs warrants caution

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Question 1.3 (6 marks total)

Risk Assessment (2 marks):

• Moderate-risk patient: MV >48 hours anticipated, but no coagulopathy (platelets 145, INR 1.2)
• Enteral nutrition commenced (protective effect on mucosa)
• Hemodynamically relatively stable (low-dose noradrenaline)

Recommendation (2 marks):

Option 1 - Commence SUP (acceptable answer):

• Agent: Pantoprazole 40 mg IV once daily (or via NJ tube if stable)
• Rationale: MV anticipated >48 hours is a risk factor; post-operative surgical patient

Option 2 - Withhold SUP initially (also acceptable answer):

• Rationale: Only one risk factor (MV); no coagulopathy; receiving EN
• Monitor closely; commence SUP if develops coagulopathy or septic deterioration

Duration and Discontinuation Criteria (2 marks):

1. Continue SUP until:

   • Extubation from mechanical ventilation
   • Resolution of any developing coagulopathy
   • Established full enteral nutrition for >48 hours
   • Transition to ward care

2. Do NOT continue:

   • Indefinitely beyond ICU stay
   • At hospital discharge unless pre-existing indication (GERD, peptic ulcer disease)

3. Convert to oral/enteral route:

   • When tolerating full EN; NG/NJ pantoprazole 40 mg daily

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Common Mistakes:

• Quoting outdated bleeding rates (15-20%) instead of modern rates (1-4%)
• Not discussing the lack of mortality benefit in SUP-ICU/PEPTIC
• Recommending indefinite SUP without de-escalation criteria
• Not mentioning enteral nutrition's protective role
• Failing to discuss Cook's risk factors

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SAQ 2: Clinical Decision-Making and Adverse Effects

Time Allocation: 10 minutes
Total Marks: 20

Stem: A 72-year-old man has been in ICU for 18 days following severe community-acquired pneumonia with ARDS and septic shock. He has been receiving pantoprazole 40 mg IV daily since admission. He is now on day 14 of invasive mechanical ventilation, weaning slowly on CPAP + PS, receiving enteral nutrition at 80 mL/h, and is hemodynamically stable off vasopressors. His platelet count is 245 × 10⁹/L and INR 1.1.

The nursing staff ask if stress ulcer prophylaxis should be continued.

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Question 2.1 (6 marks)

Discuss the potential adverse effects of prolonged proton pump inhibitor use in the ICU setting.

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Question 2.2 (6 marks)

Critically evaluate the role of enteral nutrition in stress ulcer prophylaxis. Does enteral nutrition alone provide adequate protection against GI bleeding?

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Question 2.3 (8 marks)

Based on the clinical scenario and evidence, what is your recommendation regarding stress ulcer prophylaxis for this patient? Include your justification and a de-escalation strategy.

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Model Answer

Question 2.1 (6 marks total)

Adverse Effects of Prolonged PPI Use in ICU (1 mark each, max 6):

1. Clostridioides difficile Infection (CDI):

   • OR 1.3-2.0 in observational studies
   • Mechanism: Reduced gastric acid allows C. diff spore survival
   • Clinical: New diarrhea on PPI should prompt CDI testing

2. Hospital-Acquired Pneumonia (HAP)/VAP:

   • OR 1.2-1.5 (controversial; PEPTIC showed no difference)
   • Mechanism: Alkaline gastric pH → bacterial overgrowth → aspiration
   • Mitigated by head of bed elevation, oral care

3. Drug Interactions:

   • CYP2C19 inhibition: Clopidogrel (reduced antiplatelet effect), phenytoin, tacrolimus
   • Important in patients with multiple comorbidities

4. Hypomagnesemia:

   • Reduced intestinal Mg2+ absorption
   • Risk increases with duration >1 week
   • May cause arrhythmias, muscle weakness

5. Acute Interstitial Nephritis:

   • Rare but serious
   • Consider if unexplained AKI on prolonged PPI

6. Vitamin B12 Deficiency:

   • Reduced absorption with prolonged use
   • Less relevant in acute ICU setting

7. Enteral Feed Interactions:

   • May reduce absorption of some nutrients
   • Timing of PPI relative to feeds may matter

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Question 2.2 (6 marks total)

Physiological Rationale for EN as Protection (2 marks):

1. Luminal nutrients maintain mucosal blood flow and prostaglandin synthesis
2. Enteral feeding prevents mucosal atrophy (maintains epithelial barrier)
3. Feed buffers gastric acid (pH rises from 2-3 to 5-6)
4. Stimulates bicarbonate and mucus secretion

Evidence (2 marks):

1. Observational studies: Patients receiving EN have lower GI bleeding rates than those nil-by-mouth or on PN
2. Small RCTs (Pinilla 2001): EN alone vs EN + SUP showed no difference in bleeding (0% in both groups)
3. No large RCTs directly comparing EN alone vs SUP in high-risk patients
4. SUP-ICU/PEPTIC: Did not stratify by EN status; cannot definitively answer this question

Guideline Positions (2 marks):

• ESPEN 2019: EN may provide adequate protection in low-risk patients; pharmacological SUP may be omitted if receiving EN with no other risk factors
• ASPEN/SCCM 2016: SUP recommended regardless of EN in high-risk patients
• ANZICS: Consider EN as part of prophylaxis strategy; individualize approach
• Bottom line: EN likely provides protection; may be sufficient in low-risk patients; insufficient evidence to replace SUP in high-risk patients

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Question 2.3 (8 marks total)

Risk Assessment (2 marks):

• Current risk status: LOW

  • Hemodynamically stable (off vasopressors)
  • No coagulopathy (platelets 245, INR 1.1)
  • Receiving full enteral nutrition (80 mL/h)
  • Weaning from mechanical ventilation

• Risk factors resolved:

  • No longer in septic shock
  • Coagulation normalized
  • Full EN established

Recommendation (3 marks):

De-escalate and discontinue SUP:

1. Immediate: Convert IV pantoprazole to enteral pantoprazole 40 mg via NG/NJ (cost-effective)

2. Within 24-48 hours: Discontinue PPI if:

   • Remains hemodynamically stable
   • Tolerating full EN (>48-72 hours)
   • No signs of GI bleeding
   • Weaning progresses (approaching extubation)

3. At extubation: Definitively cease SUP if no other indication

Justification (3 marks):

1. Evidence-based: SUP-ICU showed no mortality benefit; benefits modest (NNT 59)
2. Risk-benefit shifted: After 18 days on PPI, adverse effect risk (C. diff, hypomagnesemia) may outweigh benefit in now low-risk patient
3. Enteral nutrition protective: Full EN for >48 hours provides mucosal protection
4. De-escalation appropriate: Risk factors (shock, MV, coagulopathy) have resolved
5. Stewardship: Inappropriate continuation contributes to hospital-wide overuse; automatic stop at ICU discharge should be standard

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Common Mistakes:

• Continuing SUP indefinitely without reassessment
• Not recognizing that risk factors have resolved
• Not mentioning adverse effects of prolonged PPI use
• Not discussing role of EN in mucosal protection

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11. Hot Cases (2 Scenarios)

Hot Case 1: GI Bleeding in ICU Patient on SUP

Setting: ICU Bed 12
Duration: 20 minutes (10 min assessment + 10 min discussion)
Equipment: Ventilator, monitors, IV pumps, charts, nasogastric tube

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Actor/Simulator Briefing (Not given to candidate):

Patient Details:

• Age: 67 years
• Gender: Male
• Admission diagnosis: Severe community-acquired pneumonia, ARDS
• Day of ICU stay: Day 5

History:

• PMHx: COPD, hypertension, atrial fibrillation (on warfarin prior to admission - held)
• Intubated day 1, currently on SIMV + PS, FiO2 0.45, PEEP 10
• Receiving pantoprazole 40 mg IV daily since admission
• EN via NG at 60 mL/h since day 2
• Developed large-volume coffee-ground NG aspirate 4 hours ago (300 mL)

Examination Findings:

• General: Sedated, RASS -2, intubated
• Airway: ETT in situ, cuff pressure 25 cmH2O
• Breathing: RR 18 (set 12, 6 spontaneous), equal air entry, SpO2 94%
• Circulation: HR 105, BP 95/55 (MAP 68), cool peripheries, mottled knees, noradrenaline 0.1 mcg/kg/min (just started)
• Disability: RASS -2, pupils 3 mm bilaterally reactive
• Exposure: Abdomen soft, mildly distended, NG on free drainage with old blood, no melena yet

Charts/Data Available:

• Hb: 95 g/L (was 118 g/L yesterday)
• Platelets: 125 × 10⁹/L
• INR: 1.4, APTT: 38s
• Lactate: 2.8 mmol/L (was 1.2)
• Crossmatch: 2 units PRBCs in blood bank

Current Management:

• Ventilator: SIMV + PS, FiO2 0.45, PEEP 10, Vt 450 mL
• Infusions: Propofol 100 mg/h, fentanyl 50 mcg/h, noradrenaline 0.1 mcg/kg/min
• Fluids: Sodium chloride 0.9% at 80 mL/h
• EN: Held 2 hours ago due to bloody aspirate
• Pantoprazole: Being prepared as 80 mg IV bolus

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Candidate Task:

"You are the ICU registrar on call. This 67-year-old man was admitted 5 days ago with severe CAP and ARDS. He has been receiving stress ulcer prophylaxis with pantoprazole. The nursing staff have noted coffee-ground NG aspirate and are concerned about upper GI bleeding. Please assess the patient and present your findings and management plan to me, the consultant."

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Expected Performance:

Assessment Phase (10 minutes) - 15 marks

History (3 minutes) - 3 marks:

• Collateral from nurse: When did aspirate start? Volume? Color? Any hematemesis?
• Review charts: Hb trend (dropping), anticoagulation history (warfarin held)
• PMHx: Risk factors for peptic ulcer disease, H. pylori, previous GI bleeding
• Current medications: Any NSAIDs, steroids?

Examination (5 minutes) - 8 marks:

A - Airway (1 mark):

• ETT secure, cuff pressure appropriate
• Consider size of ETT for potential re-intubation if massive hematemesis

B - Breathing (2 marks):

• Assess for aspiration (secretions, desaturation)
• Note ventilator settings (may need to increase support if shock worsens)

C - Circulation (3 marks):

• Recognize shock: Tachycardia, hypotension, mottling, cool peripheries
• Note vasopressor requirement (new onset)
• IV access: Large-bore, availability of blood products

D - Disability (1 mark):

• Sedation level: RASS -2 (appropriate for potential procedure)
• GCS if sedation lightened

E - Exposure (1 mark):

• Abdominal exam: Distension, tenderness, melena per rectum
• NG tube: Confirm position, assess aspirate

Chart Review (2 marks):

• Hb drop (95 from 118 = clinically significant)
• Lactate rise (suggests hypoperfusion)
• Coagulation (INR 1.4 - mild coagulopathy)

One-Minute Summary (2 minutes) - 2 marks:

"This is a 67-year-old man, day 5 of ICU for severe CAP and ARDS, who has developed clinically significant upper GI bleeding. He has coffee-ground NG aspirate with a hemoglobin drop from 118 to 95 g/L and new vasopressor requirement. He was receiving pantoprazole prophylaxis. His coagulation is mildly deranged with INR 1.4. Key issues are: upper GI hemorrhage likely stress ulcer or peptic ulcer disease, hypovolemic shock, and ARDS. Immediate priorities are resuscitation, blood transfusion, conversion to high-dose acid suppression, and urgent gastroenterology consultation for endoscopy."

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Discussion Phase (10 minutes) - 15 marks

Opening Question: "What is your immediate management plan?"

Expected Answer (4 marks):

1. Resuscitation:

   • Two large-bore IV cannulae (if not already)
   • Crystalloid bolus 500 mL
   • Blood transfusion: Order 2 units PRBCs (crossmatched available), transfuse if Hb <70 or ongoing bleeding with instability
   • Target Hb 70-90 g/L (restrictive strategy unless massive hemorrhage)

2. Optimize Acid Suppression:

   • Convert to high-dose PPI: Pantoprazole 80 mg IV bolus, then 8 mg/h infusion
   • Continue until post-endoscopy (high-risk lesion may need 72h infusion)

3. Correct Coagulopathy:

   • INR 1.4 - consider vitamin K 10 mg IV
   • If platelets <50: Platelet transfusion (not required here)
   • Hold any anticoagulation (already done)

4. Protect Airway:

   • Patient already intubated - airway secure
   • Large-bore NG to free drainage for decompression

5. Gastroenterology Consultation:

   • Urgent endoscopy within 24 hours (ideally <12 hours given ongoing signs)
   • Erythromycin 250 mg IV 30-60 min before endoscopy (improves visualization)

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Q1: "Why did this patient develop GI bleeding despite receiving pantoprazole prophylaxis?" (3 marks)

Expected Answer:

1. SUP is not 100% effective: Even with prophylaxis, clinically important bleeding occurs in 2-3% of patients
2. Possible etiologies:
   • Stress ulcer (SRMD) - despite prophylaxis
   • Pre-existing peptic ulcer disease (H. pylori, NSAID-related)
   • Acute gastric mucosal lesions (Dieulafoy, angiodysplasia)
   • Variceal bleeding (if occult liver disease)
3. Risk factors: This patient had MV >48h (high risk) + mild coagulopathy; may have had inadequate dosing or absorption issues

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Q2: "What is the evidence for high-dose PPI infusion in upper GI bleeding?" (3 marks)

Expected Answer:

• Rationale: Maintain gastric pH >6 to stabilize clot, prevent fibrinolysis
• Regimen: 80 mg IV bolus + 8 mg/h continuous infusion (for 72 hours if high-risk stigmata at endoscopy)
• Evidence: Cochrane review shows high-dose PPI reduces re-bleeding, surgery, and mortality in high-risk peptic ulcer bleeding (NNT ~12 for re-bleeding)
• Application: Use post-endoscopy for high-risk lesions (active bleeding, visible vessel); can de-escalate to oral PPI BD after 72h if stable

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Q3: "He has ARDS. How does this affect your transfusion strategy?" (3 marks)

Expected Answer:

1. Restrictive transfusion: Target Hb 70-90 g/L generally preferred in critically ill (TRICC trial)
2. ARDS considerations:
   • Avoid volume overload (worsens pulmonary edema)
   • Balance oxygen delivery (may need Hb >80 if severe ARDS with high FiO2)
   • Fresh blood products reduce TRALI risk
3. Massive hemorrhage protocol: If hemodynamically unstable despite resuscitation, may need more aggressive transfusion (1:1:1 ratio for massive transfusion)
4. Monitor: Lactate, urine output, MAP as resuscitation endpoints

---

Q4: "The family are Indigenous Australian. Are there any specific considerations?" (2 marks)

Expected Answer:

1. Communication:

   • Involve Aboriginal Health Worker (AHW) or Aboriginal Liaison Officer (ALO)
   • Family involvement in decision-making is important
   • Allow time for extended family consultation if major decisions needed

2. Cultural considerations:

   • Be sensitive to potential distrust of healthcare system
   • Explain procedures (endoscopy, transfusion) clearly and respectfully
   • Consider spiritual/cultural needs if deterioration occurs

---

Hot Case 2: Decision About SUP in Low-Risk Patient

Setting: ICU Bed 4
Duration: 20 minutes
Equipment: Ventilator, monitors, charts

---

Actor/Simulator Briefing:

Patient Details:

• Age: 45 years
• Gender: Female
• Admission diagnosis: Diabetic ketoacidosis (DKA)
• Day of ICU stay: Day 2

History:

• Type 1 diabetes, non-compliant with insulin
• Admitted with severe DKA (pH 7.05, glucose 42 mmol/L)
• Intubated for reduced GCS, now improving
• Currently pH 7.32, glucose 12 mmol/L, HCO3 16

Examination Findings:

• General: Awake, cooperative, RASS 0, intubated
• Airway: ETT in situ, passing SBT criteria
• Breathing: RR 18, SpO2 99% on CPAP + PS 5, FiO2 0.25
• Circulation: HR 88, BP 125/75, warm peripheries
• Disability: GCS E4VTM6, oriented
• Exposure: Abdomen soft, tolerating NG feeds 40 mL/h

Charts/Data:

• Hb: 142 g/L
• Platelets: 345 × 10⁹/L
• INR: 1.0
• No vasopressors, stable for 24 hours

Current Management:

• CPAP + PS 5, ready for extubation trial
• IV insulin infusion
• EN via NG at 40 mL/h
• No stress ulcer prophylaxis commenced

---

Candidate Task:

"This 45-year-old woman was admitted with severe DKA. She is now recovering and ready for extubation. The registrar from the admitting medical team has requested that stress ulcer prophylaxis be commenced 'as per routine ICU protocol.' What is your approach?"

---

Expected Performance:

Assessment Summary (5 marks):

• Recognize this is a LOW-RISK patient for GI bleeding
• No independent risk factors: MV <48 hours (expected extubation), no coagulopathy
• Receiving enteral nutrition (mucosal protection)
• Hemodynamically stable, low illness severity

Discussion Points (10 marks):

1. Explain risk stratification:

   • Cook's criteria: MV >48h (OR 15.6), coagulopathy (OR 4.3)
   • This patient: Anticipated MV <48h, no coagulopathy = low risk (<1% bleeding)

2. Evidence against routine SUP:

   • SUP-ICU: Even in "at-risk" population, bleeding rate only 4% without prophylaxis
   • No mortality benefit demonstrated
   • This patient is lower risk than SUP-ICU population

3. Potential harms of SUP:

   • C. difficile infection risk (OR 1.3-2.0)
   • Pneumonia (controversial)
   • Drug interactions
   • Cost

4. Role of enteral nutrition:

   • Provides mucosal protection
   • May be sufficient in low-risk patients

5. Recommendation:

   • Do NOT commence SUP in this low-risk patient
   • Continue enteral nutrition
   • Extubate as planned
   • No indication for pharmacological prophylaxis

6. Communication with medical team:

   • Explain evidence-based rationale
   • Many hospitals have "routine" SUP protocols that are not evidence-based
   • Stewardship: Avoiding unnecessary acid suppression reduces adverse effects

---

12. Viva Scenarios (6 Questions)

Viva Question 1: Pathophysiology and Risk Factors

Stem: "A medical student asks you to explain why ICU patients get stress ulcers. Please discuss the pathophysiology of stress-related mucosal disease."

Duration: 12 minutes

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Opening Question: "What is the pathophysiology of stress-related mucosal disease?"

Expected Answer (3 minutes):

"Stress-related mucosal disease results from a combination of factors that disrupt the normal balance between gastric mucosal defense and acid-mediated injury.

Key mechanisms include:

1. Splanchnic hypoperfusion: Critical illness causes redistribution of blood flow away from the GI tract. Shock can reduce splanchnic blood flow by 50-70%, leading to mucosal ischemia.

2. Ischemia-reperfusion injury: When perfusion is restored during resuscitation, reactive oxygen species are generated, causing further epithelial damage.

3. Loss of protective mechanisms: The normal gastric mucosal defense includes mucus, bicarbonate, and prostaglandins. Critical illness impairs these - ischemia reduces prostaglandin synthesis, and epithelial cells cannot maintain the mucus-bicarbonate barrier.

4. Acid back-diffusion: Once the mucosal barrier is damaged, hydrogen ions diffuse back into the tissue, causing submucosal edema, hemorrhage, and necrosis.

5. Systemic inflammation: The systemic inflammatory response in critical illness includes cytokines (TNF-α, IL-1β) that exacerbate mucosal injury."

---

Follow-up Question 1: "What are the independent risk factors for clinically important GI bleeding?"

Expected Answer (2 minutes):

"The landmark Cook et al. 1994 prospective cohort study identified two independent risk factors:

1. Mechanical ventilation for more than 48 hours: Odds ratio 15.6 (95% CI 3.0-80.0)
2. Coagulopathy: Platelets less than 50, INR greater than 1.5, or therapeutic anticoagulation. Odds ratio 4.3 (95% CI 1.8-10.1)

Patients with both risk factors have the highest bleeding risk - approximately 8-12%. Those with neither risk factor have less than 1% bleeding risk.

Other factors associated in univariate analysis include severe burns, traumatic brain injury, spinal cord injury, septic shock, hepatic failure, and renal failure requiring RRT. However, these did not reach independent significance."

---

Follow-up Question 2: "How do these risk factors inform your decision about prophylaxis?"

Expected Answer (2 minutes):

"Based on the evidence:

1. High-risk patients (MV >48h + coagulopathy): SUP is recommended; benefit of preventing bleeding outweighs risks of prophylaxis

2. Moderate-risk patients (one risk factor): SUP is reasonable; consider patient-specific factors (severity of illness, bleeding history, drug interactions)

3. Low-risk patients (no risk factors): SUP may be omitted; SUP-ICU showed bleeding rate only 4.2% even without prophylaxis, and enteral nutrition provides some protection

This is a risk-benefit analysis. Given SUP-ICU showed no mortality benefit and modest bleeding reduction with NNT of 59, the threshold for prophylaxis should be higher than historical practice suggested."

---

Viva Question 2: Evidence Interpretation

Stem: "You are discussing stress ulcer prophylaxis at a departmental meeting. A colleague asks about the SUP-ICU trial. Please summarize the key findings."

---

Opening Question: "What were the main findings of the SUP-ICU trial?"

Expected Answer (3 minutes):

"The SUP-ICU trial was published in the New England Journal of Medicine in 2018. It was a multicenter, randomized, double-blind, placebo-controlled trial conducted across 33 ICUs in 6 European countries.

Population: 3,298 adult ICU patients at risk for GI bleeding, defined as having at least one of: shock, RRT, therapeutic anticoagulation, coagulopathy, or chronic liver disease.

Intervention: Pantoprazole 40 mg IV daily versus placebo.

Primary Outcome: 90-day all-cause mortality - there was no significant difference: 31.1% in the pantoprazole group versus 30.4% in placebo.

Secondary Outcomes:

• Clinically important GI bleeding: 2.5% versus 4.2% (absolute risk reduction 1.7%, p=0.04)
• NNT to prevent one bleeding episode: 59
• No significant difference in C. difficile infection or pneumonia

Interpretation: Pantoprazole reduced clinically important GI bleeding but did not reduce mortality. The absolute risk of bleeding was low even in the placebo group, questioning whether universal prophylaxis is necessary."

---

Follow-up Question: "What were the limitations of this trial?"

Expected Answer (2 minutes):

"Several important limitations:

1. Risk factor selection: Did not specifically include patients with MV >48 hours as the sole risk factor, which is Cook's most important criterion

2. Exclusion of PPI users: Patients already on PPIs were excluded, potentially selecting a lower-risk population

3. Power: The trial was powered for bleeding outcomes, not mortality - may have been underpowered to detect a mortality difference

4. Generalizability: European population; practice may differ in Australia/NZ

5. Enteral nutrition: High proportion of patients received EN; the trial doesn't separate the effect of SUP from EN

6. Modern ICU care: Low event rates reflect improved overall ICU care; historical bleeding rates of 15-20% no longer applicable"

---

Viva Question 3: Pharmacology

Stem: "A trainee asks you to explain the difference between PPIs and H2RAs for stress ulcer prophylaxis."

---

Opening Question: "What is the mechanism of action of proton pump inhibitors?"

Expected Answer (2 minutes):

"Proton pump inhibitors irreversibly inhibit the H+/K+-ATPase, also known as the proton pump, on the apical membrane of gastric parietal cells.

Key points:

• PPIs are prodrugs that require activation in the acidic environment of the parietal cell canaliculus
• Once activated, they form covalent disulfide bonds with cysteine residues on the proton pump
• This irreversible binding means the pump is permanently inactivated
• New pumps must be synthesized for acid secretion to return - the pump half-life is approximately 50 hours
• Full effect takes 2-5 days as successive doses inhibit newly synthesized pumps
• Result is 80-95% reduction in gastric acid secretion"

---

Follow-up Question 1: "How does this differ from H2 receptor antagonists?"

Expected Answer (2 minutes):

"H2 receptor antagonists work by competitive, reversible inhibition of histamine H2 receptors on parietal cells.

Key differences:

1. Reversibility: H2RAs are reversible; PPIs are irreversible
2. Potency: H2RAs reduce acid by 50-70%; PPIs reduce by 80-95%
3. Onset: H2RAs act within 30-60 minutes; PPIs take longer but last longer
4. Tachyphylaxis: H2RAs develop tolerance within 48-72 hours due to receptor upregulation; PPIs do not develop tachyphylaxis
5. Pathway specificity: H2RAs only block histamine stimulation; PPIs block the final common pathway for all acid secretion"

---

Follow-up Question 2: "What are the important drug interactions with PPIs?"

Expected Answer (2 minutes):

"PPIs are metabolized by CYP2C19 and CYP3A4, leading to several important interactions:

1. Clopidogrel: PPIs inhibit CYP2C19, which converts clopidogrel to its active metabolite. This may reduce antiplatelet effect. Pantoprazole has the lowest CYP2C19 inhibition and is often preferred in patients on clopidogrel, though clinical significance is debated.

2. Phenytoin: Increased phenytoin levels due to CYP2C19 inhibition - monitor levels

3. Tacrolimus: Increased levels - monitor closely in transplant patients

4. Methotrexate: Reduced renal elimination - increased toxicity risk

5. Mycophenolate: Reduced absorption at higher gastric pH

6. Warfarin: Variable effects on INR - monitor more frequently

When drug interactions are a concern, H2RAs (particularly famotidine) have fewer interactions and may be preferred."

---

Viva Question 4: Clinical Decision-Making

Stem: "A patient has been in ICU for 10 days on mechanical ventilation and receiving pantoprazole. She is now ready for extubation and ward transfer. Should stress ulcer prophylaxis be continued?"

---

Opening Question: "What factors would you consider in deciding whether to continue SUP?"

Expected Answer (3 minutes):

"I would assess whether the original indications for SUP still apply:

Risk factor reassessment:

1. Is she still on mechanical ventilation? - No, she's being extubated
2. Does she have coagulopathy? - Need to check platelets, INR
3. Is she receiving enteral nutrition? - If yes, this provides mucosal protection
4. Any history of GI bleeding or peptic ulcer disease?

Factors favoring discontinuation:

• Extubation removes the primary risk factor (MV >48h)
• Resolution of acute illness
• Tolerating oral intake or full EN
• No coagulopathy
• No pre-existing indication (GERD, Barrett's, peptic ulcer disease)

Factors favoring continuation:

• Ongoing coagulopathy
• Recent GI bleeding episode
• Pre-existing peptic ulcer disease or GERD
• Continuing high-dose steroids with NSAIDs/antiplatelet agents

In most cases, SUP should be discontinued at ICU discharge or extubation. Inappropriate continuation is a common problem - studies show 30-50% of patients inappropriately continue acid suppression at hospital discharge."

---

Follow-up Question: "The medical team want to continue the PPI 'just in case.' How do you respond?"

Expected Answer (2 minutes):

"I would explain the evidence-based approach:

1. No mortality benefit: Neither SUP-ICU nor PEPTIC showed mortality reduction with prophylaxis

2. Potential harms: Prolonged PPI use increases C. difficile risk (OR 1.3-2.0), and there are concerns about pneumonia, hypomagnesemia, and drug interactions

3. Risk factors have resolved: If she's no longer ventilated and has no coagulopathy, she's a low-risk patient

4. Hospital stewardship: Inappropriate continuation of acid suppression is a widespread problem and contributes to adverse effects and healthcare costs

5. Clear indication needed: PPIs should only be continued beyond ICU if there's a documented indication - GERD, Barrett's, active peptic ulcer disease, or therapeutic anticoagulation with high bleeding risk

I would recommend discontinuing the PPI and documenting the rationale. If she develops a new indication, it can be restarted."

---

Viva Question 5: Adverse Effects and Risk-Benefit

Stem: "A colleague is concerned about C. difficile infection risk with PPIs. How do you counsel them about the risk-benefit of stress ulcer prophylaxis?"

---

Opening Question: "What is the association between PPIs and C. difficile infection?"

Expected Answer (3 minutes):

"There is an association between PPI use and C. difficile infection, though the clinical significance is debated.

Evidence:

• Observational studies show OR 1.3-2.0 for CDI with PPI use
• Meta-analyses consistently show increased risk
• However, SUP-ICU and PEPTIC trials showed no significant difference in CDI rates between PPI and placebo/H2RA groups

Mechanism:

• Gastric acid normally kills C. difficile spores (pH <4.5 kills vegetative forms)
• Acid suppression allows spore survival and passage to the colon
• In the colon, if the microbiome is disrupted (antibiotics), spores germinate and cause infection

Perspective:

• Absolute risk remains low in trials (0.3-0.9%)
• The association in observational studies may be confounded - sicker patients more likely to receive PPIs and more susceptible to CDI
• Risk must be balanced against benefit of preventing GI bleeding

Clinical approach:

• Use SUP only when indicated (high-risk patients)
• Discontinue as soon as risk factors resolve
• Test for C. difficile if new diarrhea develops on PPI"

---

Follow-up Question: "How do you balance the risks and benefits of SUP?"

Expected Answer (3 minutes):

"The risk-benefit calculation depends on the patient's bleeding risk:

High-risk patients (MV >48h + coagulopathy):

• GI bleeding risk: 8-12% without prophylaxis
• NNT for bleeding prevention: ~12-15
• CDI risk: ~1% (NNH ~100)
• Benefit outweighs risk - SUP recommended

Moderate-risk patients (one risk factor):

• GI bleeding risk: 2-4%
• NNT: 30-50
• CDI risk: ~1%
• Risk-benefit more balanced - individualize based on patient factors

Low-risk patients (no risk factors, receiving EN):

• GI bleeding risk: <1%
• NNT: >100
• CDI risk: ~1%
• Risk may outweigh benefit - consider omitting SUP

Summary:

• SUP is not harm-free
• Benefits are modest (NNT 59 in SUP-ICU)
• No mortality benefit demonstrated
• Reserve for high-risk patients; de-escalate when risk resolves"

---

Viva Question 6: Australian Context and Indigenous Health

Stem: "You are developing a departmental guideline for stress ulcer prophylaxis. What Australian-specific factors should be considered?"

---

Opening Question: "What are the key Australian guidelines and considerations for SUP?"

Expected Answer (3 minutes):

"There are several Australian-specific considerations:

Guidelines:

• ANZICS does not mandate universal SUP; recommends individualized approach based on risk stratification
• Therapeutic Guidelines Australia (eTG) recommends SUP in patients with MV >48h and/or coagulopathy
• Either PPIs or H2RAs acceptable; PPIs marginally more effective

Pharmacological considerations:

• Pantoprazole most commonly used IV PPI in Australian ICUs
• Famotidine is the H2RA of choice (ranitidine withdrawn 2020)
• IV formulations on hospital formulary; oral formulations for ward transfer

PEPTIC trial significance:

• Large proportion of PEPTIC conducted in Australia/NZ (50 ICUs)
• Directly applicable to Australian practice
• Showed either PPI or H2RA acceptable

Remote and rural considerations:

• Limited access to endoscopy in rural hospitals
• May have lower threshold for SUP if endoscopy not locally available
• RFDS retrieval for GI bleeding is resource-intensive
• Telemedicine consultation with gastroenterology for remote sites"

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Follow-up Question: "What Indigenous health considerations are relevant?"

Expected Answer (3 minutes):

"Several important considerations for Aboriginal and Torres Strait Islander patients and Māori:

Aboriginal and Torres Strait Islander Peoples:

• Higher rates of peptic ulcer disease, H. pylori infection, and GI malignancy
• Higher rates of alcohol-related liver disease (coagulopathy)
• Diabetes-related gastroparesis may affect GI function
• May present later with more severe critical illness

Cultural considerations:

• Family and community involvement in healthcare decisions
• Aboriginal Health Workers (AHWs) and Aboriginal Liaison Officers (ALOs) facilitate communication
• May have historical distrust of healthcare system
• Allow time for family consultation for major decisions

Practical implications:

• Lower threshold for SUP in Indigenous patients with multiple risk factors
• Consider H. pylori testing if history of peptic ulcer disease
• Ensure clear communication about treatment rationale
• Involve AHW/ALO early if GI bleeding occurs or deterioration

Māori Health (NZ):

• Similar higher rates of diabetes, CKD, liver disease
• Whānau-centered care - involve extended family
• Māori Health Workers for communication support
• Respect tikanga (Māori customs and protocols)"

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13. Interactive Elements

Decision Algorithm: Stress Ulcer Prophylaxis

STEP 1: Assess Risk Factors

┌─────────────────────────────────────────────────────────────┐
│                  STRESS ULCER RISK ASSESSMENT               │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│  □ Mechanical Ventilation expected >48 hours?    YES / NO  │
│                                                             │
│  □ Coagulopathy present?                         YES / NO  │
│    (Platelets <50 OR INR >1.5 OR therapeutic anticoag)     │
│                                                             │
│  □ Other high-risk factors?                      YES / NO  │
│    - Burns >35% TBSA                                        │
│    - Traumatic brain injury                                 │
│    - Spinal cord injury                                     │
│    - Hepatic failure                                        │
│    - History of GI bleeding                                 │
│                                                             │
│  □ Receiving Enteral Nutrition?                  YES / NO  │
│                                                             │
└─────────────────────────────────────────────────────────────┘

STEP 2: Risk Category and Recommendation

┌───────────────────────────────────────────────────────────────────┐
│ RISK CATEGORY          │ RECOMMENDATION                          │
├─────────────────────────┼─────────────────────────────────────────┤
│ HIGH RISK               │ COMMENCE SUP                            │
│ (MV >48h + coagulopathy)│ PPI (pantoprazole 40 mg IV/PO daily)   │
│                         │ Continue until risk factors resolve     │
├─────────────────────────┼─────────────────────────────────────────┤
│ MODERATE RISK           │ CONSIDER SUP                            │
│ (MV >48h only OR        │ Individualize based on other factors   │
│ coagulopathy only)      │ If using: PPI or H2RA acceptable       │
├─────────────────────────┼─────────────────────────────────────────┤
│ LOW RISK                │ OMIT SUP                                │
│ (No MV >48h, no coag,   │ Continue enteral nutrition             │
│ receiving EN)           │ Monitor clinically                      │
├─────────────────────────┼─────────────────────────────────────────┤
│ CONTRAINDICATION        │ HOLD SUP                                │
│ (Active GI bleeding)    │ Manage bleeding therapeutically        │
└─────────────────────────┴─────────────────────────────────────────┘

STEP 3: Agent Selection

┌────────────────────────────────────────────────────────────────────┐
│                    AGENT SELECTION GUIDE                           │
├────────────────────────────────────────────────────────────────────┤
│                                                                    │
│  PREFER PPI (Pantoprazole 40 mg IV/PO daily)                      │
│  ├─ High-risk patients (MV + coagulopathy)                        │
│  ├─ History of peptic ulcer or GI bleeding                        │
│  ├─ Concurrent NSAIDs or antiplatelet agents                      │
│  ├─ Hepatic failure (coagulopathy)                                │
│  └─ Burns, TBI, spinal cord injury                                │
│                                                                    │
│  PREFER H2RA (Famotidine 20 mg IV/PO BD)                          │
│  ├─ Concern for PPI drug interactions (clopidogrel, tacrolimus)   │
│  ├─ Previous C. difficile infection                               │
│  ├─ Short anticipated ICU stay (<5 days)                          │
│  └─ Renal impairment (dose adjust)                                │
│                                                                    │
│  NEITHER REQUIRED                                                  │
│  ├─ Low-risk patient receiving enteral nutrition                  │
│  ├─ Short-term MV (<48 hours)                                     │
│  └─ No coagulopathy, low illness severity                         │
│                                                                    │
└────────────────────────────────────────────────────────────────────┘

STEP 4: Duration and De-escalation

┌────────────────────────────────────────────────────────────────────┐
│                    DE-ESCALATION CRITERIA                          │
├────────────────────────────────────────────────────────────────────┤
│                                                                    │
│  DISCONTINUE SUP WHEN ALL of the following:                       │
│                                                                    │
│  ☐ Extubated from mechanical ventilation                          │
│                                                                    │
│  ☐ Coagulopathy resolved (platelets >50, INR <1.5)               │
│                                                                    │
│  ☐ Full enteral nutrition tolerated for >48-72 hours             │
│                                                                    │
│  ☐ Hemodynamically stable (off vasopressors)                      │
│                                                                    │
│  ☐ No active GI bleeding                                          │
│                                                                    │
│  ☐ No pre-existing indication (GERD, Barrett's, PUD)             │
│                                                                    │
│  ═══════════════════════════════════════════════════════════════  │
│                                                                    │
│  AT WARD TRANSFER:                                                 │
│  → Automatic stop order unless documented ongoing indication      │
│                                                                    │
│  AT HOSPITAL DISCHARGE:                                            │
│  → Remove from discharge medications unless pre-existing Rx       │
│                                                                    │
└────────────────────────────────────────────────────────────────────┘

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Risk Stratification Tool

Stress Ulcer Bleeding Risk Calculator

Total Score: ___/15

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