Counter-Regulatory Impairment in Critical Illness:

Multiple factors impair the counter-regulatory response in ICU patients:

1. Sepsis: Pro-inflammatory cytokines suppress glucagon release and impair adrenal axis function

2. Adrenal Insufficiency: Critical illness-related corticosteroid insufficiency (CIRCI) is present in 10-20% of septic shock patients; relative cortisol deficiency impairs gluconeogenesis

3. Hepatic Failure: Reduced glycogen stores (typically depleted within 24-48 hours of fasting) and impaired gluconeogenesis; spontaneous hypoglycaemia is a poor prognostic sign

4. Beta-Blocker Therapy: Masks autonomic warning symptoms (tremor, tachycardia) and may impair glycogenolysis

5. Renal Failure: Reduced gluconeogenesis (kidney contributes 20-25% in fasted state), reduced insulin clearance

6. Repeated Hypoglycaemia: Leads to hypoglycaemia-associated autonomic failure (HAAF) with defective counter-regulation and unawareness

7. Sedation and Ventilation: Masks symptoms and signs of hypoglycaemia

Pharmacology: Dextrose and Glucagon

Dextrose (Glucose) Solutions:

D10 vs D50 for Treatment:

The choice between D10 and D50 for acute hypoglycaemia treatment has been debated: [11,12]

D10 (10% Dextrose) - Preferred in ICU:

• Advantages:
  • More physiological glucose rise
  • Lower risk of rebound hyperglycaemia
  • Can be given peripherally without significant phlebitis
  • Easier to titrate
• Dosing: 100-150 mL IV over 5-10 minutes (10-15g glucose)
• Expected glucose rise: Approximately 2-4 mmol/L per 10g glucose

D50 (50% Dextrose):

• Advantages:
  • Smaller volume for same glucose load
  • Faster administration
• Disadvantages:
  • Highly hypertonic (2525 mOsm/L) - causes venous irritation and thrombophlebitis
  • Greater risk of rebound hyperglycaemia
  • Tissue necrosis if extravasation occurs
• Should be given via central venous catheter or large-bore peripheral access only
• Dosing: 25-50 mL IV (12.5-25g glucose)

Glucagon:

Octreotide for Sulphonylurea Overdose:

In sulphonylurea-induced hypoglycaemia, octreotide (50-100 mcg SC every 8 hours) is recommended as adjunctive therapy. [13] Mechanism: Inhibits insulin secretion from beta-cells by blocking ATP-sensitive potassium channels (KATP).

Pathology: Consequences of Hypoglycaemia

Neurological Injury:

The brain is exquisitely vulnerable to hypoglycaemia because:

• Obligate glucose dependence (consumes 120g/day, 20% of total body glucose consumption)
• Minimal glycogen reserves (sufficient for only 1-2 minutes)
• Limited ketone utilisation in acute hypoglycaemia
• Blood-brain barrier restricts alternative fuel entry

Neuronal death from hypoglycaemia follows a distinct pattern: [14]

• Cortex (especially layers 2 and 3)
• Hippocampus (CA1 region)
• Caudate nucleus
• Differs from hypoxic-ischemic injury (which affects watershed zones and basal ganglia)

Mechanisms of Neuronal Death:

1. ATP depletion leading to ionic pump failure
2. Excitotoxicity (excessive glutamate release and NMDA receptor activation)
3. Oxidative stress from reperfusion (post-glucose correction)
4. Zinc translocation and mitochondrial dysfunction

Cardiovascular Effects:

• QTc prolongation (arrhythmia risk)
• Increased catecholamine release (tachycardia, hypertension)
• Platelet activation and endothelial dysfunction
• Increased myocardial oxygen demand

---

Clinical Presentation

ICU Admission Scenarios

Scenario 1: Iatrogenic Hypoglycaemia During Insulin Infusion

• Most common scenario in modern ICUs
• Patient on variable-rate insulin infusion for sepsis/hyperglycaemia
• Routine glucose check shows value of 2.8 mmol/L
• Often asymptomatic due to sedation
• History: Nutrition interruption, sudden improvement in illness, renal function decline

Scenario 2: Hypoglycaemia in Hepatic Failure

• Patient with acute liver failure (paracetamol overdose, viral hepatitis)
• Spontaneous hypoglycaemia without exogenous insulin
• Poor prognostic indicator (reflects loss of gluconeogenic capacity)
• May require continuous dextrose infusion at 10-15 g/hour

Scenario 3: Hypoglycaemia with Adrenal Insufficiency

• Septic shock patient with refractory hypotension and hypoglycaemia
• Despite dextrose administration, glucose remains low
• Consider critical illness-related corticosteroid insufficiency (CIRCI)
• Response to hydrocortisone suggests adrenal aetiology

Symptoms and Signs

Autonomic (Sympathoadrenal) Symptoms:

• Tremor
• Palpitations and tachycardia
• Sweating (diaphoresis)
• Hunger
• Anxiety and restlessness
• Pallor

Neuroglycopenic Symptoms:

• Confusion and impaired cognition
• Drowsiness and lethargy
• Visual disturbance (blurred vision, diplopia)
• Dysarthria
• Ataxia and incoordination
• Seizures
• Coma

Challenges in ICU Patients:

Recognition of hypoglycaemia in critically ill patients is challenging because:

• Sedation masks both autonomic and neuroglycopenic symptoms
• Mechanical ventilation prevents verbal communication
• Pre-existing encephalopathy (septic, hepatic, uraemic) obscures neurological changes
• Beta-blockers mask tachycardia
• Vasopressors may cause diaphoresis independent of glucose
• Autonomic neuropathy (diabetic) impairs symptom recognition

This emphasises the critical importance of protocolised glucose monitoring rather than symptom-based detection.

Differential Diagnosis of Low Glucose

When encountering hypoglycaemia in the ICU, consider causes beyond iatrogenic insulin:

HYPO CAUSES Mnemonic Applied:

1. H - Hepatic Failure

   • Acute liver failure: Grade III-IV encephalopathy
   • Cirrhosis with acute decompensation
   • Reduced glycogen stores and gluconeogenesis

2. Y - Yield of Insulin Excessive

   • IV insulin infusion overdose
   • Subcutaneous insulin without nutrition
   • Insulin clearance reduced (renal/hepatic failure)

3. P - Post-Prandial/Nutrition Interruption

   • Enteral feed stopped for procedures
   • Parenteral nutrition interruption
   • Malabsorption

4. O - Opioids/Sedation

   • Masking symptoms rather than causing hypoglycaemia

5. C - Cortisol Deficiency

   • Adrenal insufficiency (primary or secondary)
   • Steroid withdrawal after prolonged use
   • CIRCI in septic shock

6. A - Alcoholism/Starvation

   • Alcoholic ketoacidosis with depleted glycogen
   • Starvation with malnutrition
   • Anorexia nervosa

7. U - Uraemia/Renal Failure

   • Reduced insulin clearance
   • Reduced renal gluconeogenesis
   • Dialysis-related hypoglycaemia (glucose-free dialysate)

8. S - Sepsis

   • Increased peripheral glucose consumption
   • Impaired hepatic gluconeogenesis
   • Adrenal dysfunction

9. E - Elderly

   • Reduced glycogen stores
   • Polypharmacy (sulphonylureas, insulin)
   • Reduced counter-regulatory responses

10. S - Sulphonylureas and Insulin

    • Long-acting agents (glibenclamide, glimepiride)
    • Accumulation in renal failure
    • Drug interactions

---

Investigations

Bedside Tests

Point-of-Care Glucose Measurement:

All ICUs should have validated point-of-care (POC) glucose meters with documented quality control procedures. [15]

Accuracy Considerations:

• Arterial or venous blood preferred over capillary samples in critically ill patients
• POC meters may have reduced accuracy in: [16]
  • Hypotension/shock (peripheral hypoperfusion)
  • Severe anaemia (Hct below 0.30)
  • Severe polycythaemia (Hct above 0.55)
  • Peripheral oedema
  • "Medications: paracetamol, vitamin C, dopamine, mannitol"

Blood Gas Analyser:

• Many ABG machines measure glucose
• Generally more accurate than POC meters
• Should be used to confirm POC results in haemodynamically unstable patients

Laboratory Plasma Glucose:

• Gold standard for accuracy
• Delay in results limits utility for acute management
• Important for trend monitoring and protocol adjustment

Additional Investigations in Refractory Hypoglycaemia

If hypoglycaemia is refractory despite dextrose and insulin cessation, or if spontaneous hypoglycaemia occurs without exogenous insulin, further investigation is warranted:

Endocrine Workup:

• Cortisol: 9am cortisol below 100 nmol/L suggestive of adrenal insufficiency; below 276 nmol/L with haemodynamic instability suggests CIRCI
• ACTH stimulation test: 250 mcg IV cosyntropin, measure cortisol at 0 and 60 minutes
• C-peptide: Elevated in endogenous insulin excess (insulinoma, sulphonylurea); suppressed in exogenous insulin
• Insulin level: At time of hypoglycaemia
• Pro-insulin: Elevated in insulinoma
• Sulphonylurea screen: Plasma or urine
• Beta-hydroxybutyrate: Appropriately elevated during hypoglycaemia with insulin deficiency; suppressed with insulin excess
• IGF-2: If non-islet cell tumour hypoglycaemia suspected

Hepatic Function:

• LFTs with coagulation profile
• Ammonia level
• Lactate (may be elevated in hepatic failure)

Imaging:

• CT pancreas with contrast (if insulinoma suspected)
• CT abdomen (for large tumours causing hypoglycaemia)

---

ICU Management

Initial Resuscitation: Treatment of Acute Hypoglycaemia

Step 1: Recognition and Confirmation

• Suspect hypoglycaemia in any critically ill patient with altered consciousness, seizures, or autonomic symptoms
• Confirm with POC glucose measurement
• If glucose below 4.0 mmol/L, treat immediately

Step 2: Immediate Dextrose Administration

Preferred Treatment (D10):

• Dose: D10 100-150 mL IV over 5-10 minutes (10-15g glucose)
• Route: Peripheral or central IV access
• Rationale: Gradual glucose rise, lower rebound hyperglycaemia risk, less venous irritation

Alternative Treatment (D50):

• Dose: D50 25-50 mL IV bolus (12.5-25g glucose)
• Route: Central line preferred; large-bore peripheral if no central access
• Precautions: Avoid extravasation (tissue necrosis risk)

If No IV Access:

• Glucagon 1 mg IM (onset 10-15 min)
• Oral glucose if patient conscious and airway protected

Step 3: Stop/Reduce Insulin

• Immediately cease insulin infusion if running
• Review insulin dose and adjust protocol
• Document time of insulin cessation

Step 4: Recheck Glucose

• Recheck glucose 15-30 minutes after treatment
• Target: Glucose above 5.0 mmol/L before resuming insulin
• Repeat dextrose bolus if glucose remains below 4.0 mmol/L

Step 5: Investigate Cause

• Nutrition interruption? (Resume feeding)
• Insulin dose too high? (Adjust protocol)
• Renal function declining? (Reduce insulin dose)
• Hepatic failure? (May need continuous dextrose)
• Sepsis? (Consider adrenal insufficiency)

Refractory Hypoglycaemia Management

If hypoglycaemia persists despite repeated dextrose boluses:

Continuous Dextrose Infusion:

• Start D10 at 100-200 mL/hour (10-20 g glucose/hour)
• Increase D10 concentration to D20 if fluid restriction required
• Monitor glucose every 1-2 hours and titrate

Glucagon:

• Consider glucagon 1 mg IV/IM if dextrose access delayed
• Repeat after 15 minutes if no response
• Note: Ineffective if glycogen stores depleted (hepatic failure, starvation)

Glucocorticoids:

• If adrenal insufficiency suspected or refractory hypoglycaemia in sepsis:
• Hydrocortisone 100 mg IV bolus, then 50 mg IV every 6 hours
• Response within hours supports adrenal aetiology

Octreotide (for sulphonylurea overdose):

• 50-100 mcg SC every 8 hours
• Inhibits insulin release from beta-cells
• Continue for 24-72 hours depending on sulphonylurea half-life

Prevention: Glucose Management Protocols

Evidence-Based Target Range:

Based on the totality of evidence from NICE-SUGAR, GLUCONTROL, and VISEP trials, current guidelines recommend: [17,18,19]

Protocol Elements for Safe Insulin Infusion:

1. Validated Protocol: Use a published, validated protocol (e.g., Yale Protocol, SPRINT, modified Portland) [20]

   • Column-based protocols with clear dose adjustments
   • Should include rate of change in addition to absolute glucose

2. Starting Insulin:

   • Initiate when glucose above 10 mmol/L on two consecutive measurements
   • Starting rate typically 1-2 units/hour IV
   • Adjust based on glucose response and trend

3. Monitoring Frequency:

   • Every 1-2 hours during active titration
   • Every 4 hours when stable in target range
   • More frequently (every 30 min) if glucose below 4.5 mmol/L

4. Nutrition Coordination:

   • Ensure nutrition is not interrupted without insulin adjustment
   • If enteral feed held for procedures, reduce or stop insulin
   • Consider reduced insulin requirements as patient recovers

5. High-Risk Patient Identification:

   • Hepatic failure
   • Renal failure (especially on RRT with glucose-free dialysate)
   • Sepsis with improving clinical status
   • Adrenal insufficiency
   • Elderly
   • Malnourished
   • Recent initiation of glucocorticoids followed by cessation

6. Glucose Variability Minimisation:

   • Target coefficient of variation below 20%
   • Avoid large swings in glucose
   • Use continuous glucose monitoring where available

Special Populations

Hepatic Failure:

• Spontaneous hypoglycaemia is common and indicates severe synthetic dysfunction
• Continuous dextrose infusion often required (D10 at 100-200 mL/hr)
• Monitor glucose every 1-2 hours minimum
• Hypoglycaemia is a King's College Criteria component for liver transplant

Neurocritical Care:

• Hypoglycaemia is particularly harmful to the injured brain [21]
• Target glucose 6-10 mmol/L; some guidelines suggest 7.8-10 mmol/L
• Continuous glucose monitoring beneficial
• Avoid glucose below 5.0 mmol/L in TBI/stroke patients

Renal Replacement Therapy:

• Glucose-free dialysate can cause hypoglycaemia
• Reduced insulin clearance prolongs action
• Monitor glucose more frequently during RRT
• Consider glucose-containing dialysate in high-risk patients

Paediatric Patients:

• Definition: Neonates below 2.5 mmol/L; children below 3.3 mmol/L
• Higher brain:body ratio increases vulnerability
• Treatment: D10 2-5 mL/kg IV
• Avoid D50 (osmolar load, tissue damage risk)

Aboriginal and Torres Strait Islander Patients:

• Higher prevalence of diabetes and renal disease
• May have delayed presentations with more severe metabolic derangement
• Cultural considerations for family involvement in care decisions
• Engage Aboriginal Health Workers/Liaison Officers
• Consider remote residence affecting follow-up and medication access
• Language barriers may require interpreter services

---

Monitoring and Complications

ICU-Specific Monitoring

Glucose Monitoring Schedule:

Continuous Glucose Monitoring (CGM):

• Subcutaneous CGM devices increasingly used in ICU
• Allow real-time glucose trending and alarms
• Studies show reduced hypoglycaemia incidence with CGM [22]
• Interstitial glucose lags arterial by 10-15 minutes (consider in rapid changes)
• Accuracy may be reduced in hypotension, oedema, vasopressor use

Glucose Variability Metrics:

• Standard Deviation (SD)
• Coefficient of Variation (CV): SD/mean × 100% (target below 20%)
• Mean Amplitude of Glycemic Excursions (MAGE)
• Time in Range (TIR): percentage of time 6-10 mmol/L

Complications of Hypoglycaemia

Neurological Complications:

• Seizures: May be first manifestation; respond to glucose, not anticonvulsants
• Coma: Prolonged coma despite glucose correction suggests permanent injury
• Permanent Brain Injury: Risk with glucose below 1.0 mmol/L for more than 60 minutes
• Cognitive Impairment: Memory, attention, executive function deficits

Cardiovascular Complications:

• Arrhythmias (prolonged QTc, ventricular arrhythmias)
• Myocardial ischaemia (catecholamine surge increases oxygen demand)
• Cardiac arrest (rare but reported)

Other Complications:

• Falls and injury (in ambulatory patients)
• Aspiration (if seizure or altered consciousness)
• Psychosocial: Fear of hypoglycaemia, reduced quality of life

Complications of Treatment

Rebound Hyperglycaemia:

• More common with D50 than D10
• May trigger excessive insulin administration
• Glucose variability itself harmful

Venous Irritation/Phlebitis:

• D50 causes significant venous irritation
• Use central access if available
• D10 can be given peripherally

Fluid Overload:

• Consider in fluid-restricted patients (heart failure, ARDS)
• Use concentrated dextrose (D20-D50) with central access if volume concern

Extravasation Injury:

• D50 extravasation causes tissue necrosis
• Requires immediate recognition and treatment
• Hyaluronidase may be beneficial

---

Prognosis and Outcome Measures

Mortality

Short-Term Outcomes:

Causation vs Association:

The association between hypoglycaemia and mortality does not necessarily imply causation. Several hypotheses exist: [23,24]

1. Hypoglycaemia as cause: Direct neurological/cardiac injury leads to death
2. Hypoglycaemia as marker: Sicker patients more susceptible to hypoglycaemia; hypoglycaemia reflects underlying illness severity
3. Shared vulnerability: Both hypoglycaemia susceptibility and mortality reflect impaired metabolic homeostasis

Evidence suggests a likely combination of all three mechanisms, with hypoglycaemia contributing both as an independent harmful event and as a marker of metabolic fragility.

Long-Term Outcomes

Post-ICU Morbidity:

• Cognitive impairment: Reported in survivors of severe hypoglycaemia
• PTSD and anxiety: Related to hypoglycaemia awareness/episodes
• Healthcare utilisation: Increased readmissions

Glucose Variability as Prognostic Factor:

Independent of mean glucose and hypoglycaemia, glucose variability predicts poor outcomes: [25,26]

• CV greater than 20% associated with increased mortality (OR 1.4-1.8)
• MAGE greater than 4 mmol/L associated with worse outcomes
• Variability may cause oxidative stress and inflammation

Prognostic Factors

Good Prognostic Factors:

• Rapid recognition and treatment
• Brief hypoglycaemia duration (below 30 min)
• No seizures or coma
• Young age
• No underlying hepatic failure

Poor Prognostic Factors:

• Prolonged severe hypoglycaemia (above 60 min below 2.0 mmol/L)
• Seizures or coma
• Underlying hepatic failure
• Underlying sepsis
• Elderly
• Pre-existing cognitive impairment

---

Evidence Base: Landmark Trials

NICE-SUGAR Trial (2009) [PMID: 19318384]

Design:

• Randomised controlled trial
• 6,104 patients from 42 ICUs in Australia, NZ, and Canada
• Intensive glucose control (4.5-6.0 mmol/L) vs Conventional control (below 10.0 mmol/L)
• Insulin infusion in both groups; glucose checked every 1-4 hours

Results:

Conclusions:

• Intensive glucose control increased 90-day mortality (OR 1.14; 95% CI 1.02-1.28)
• 13-fold increased risk of severe hypoglycaemia
• Findings consistent across subgroups (medical, surgical, sepsis, non-sepsis)

Impact:

• Ended the era of tight glycemic control in ICU
• Current target shifted to 6-10 mmol/L (moderate control)

Van den Berghe Leuven I Trial (2001) [PMID: 11794168]

Design:

• Single-centre RCT, 1,548 surgical ICU patients
• Intensive (4.4-6.1 mmol/L) vs Conventional (10-11.1 mmol/L)

Results:

• ICU mortality reduced with intensive control: 4.6% vs 8.0% (p below 0.04)
• Severe hypoglycaemia: 5.1% vs 0.7%

Limitations:

• Single centre, surgical ICU only
• Predominantly cardiac surgery patients
• High parenteral nutrition use (non-standard nutrition)
• Not replicated in subsequent multicentre trials

Van den Berghe Leuven II Trial (2006) [PMID: 16452557]

Design:

• Single-centre RCT, 1,200 medical ICU patients
• Same intensive vs conventional targets

Results:

• No mortality benefit in ITT analysis
• Severe hypoglycaemia: 18.7% vs 3.1%

Conclusions:

• Intensive control not beneficial in medical ICU
• Higher hypoglycaemia rate than surgical population

VISEP Trial (2008) [PMID: 18492866]

Design:

• Multicentre RCT, 537 sepsis patients
• Intensive (4.4-6.1 mmol/L) vs Conventional (10-11.1 mmol/L)
• 2×2 factorial with fluid resuscitation

Results:

• Study stopped early due to hypoglycaemia
• Severe hypoglycaemia: 17% vs 4.1%
• No mortality benefit

GLUCONTROL Trial (2009) [PMID: 19237716]

Design:

• Multicentre European RCT, 1,101 patients
• Intensive (4.4-6.1 mmol/L) vs Intermediate (7.8-10 mmol/L)

Results:

• Study stopped early for safety
• Severe hypoglycaemia: 8.7% vs 2.7%
• No mortality difference

Meta-Analysis Summary [PMID: 18779176, 24326544]

A Cochrane review and subsequent meta-analyses concluded:

• No mortality benefit for intensive glucose control (RR 1.04; 95% CI 0.97-1.11)
• 6-fold increased hypoglycaemia risk (RR 6.0; 95% CI 4.5-8.0)
• Current evidence supports moderate glucose control (6-10 mmol/L)

---

SAQ Practice

SAQ 1: Hypoglycaemia Recognition and Management

Time Allocation: 10 minutes Total Marks: 20

Stem:

A 62-year-old male with Type 2 diabetes mellitus is Day 3 in ICU following emergency laparotomy for perforated diverticulitis. He was initially septic and required noradrenaline support and mechanical ventilation. He has been on an intravenous insulin infusion for hyperglycaemia (protocol target 6-10 mmol/L). His noradrenaline has been weaned off and he is now being weaned from sedation.

The nurse calls you because his blood glucose is 2.1 mmol/L. His previous glucose 2 hours ago was 7.2 mmol/L. Enteral nutrition was ceased 3 hours ago for an abdominal CT scan and has not been restarted.

Current observations:

• HR: 110 bpm
• BP: 95/55 mmHg
• RR: 18 (on CPAP 5/5)
• SpO2: 98%
• Temp: 37.2 degrees C
• RASS: -1

Current infusions:

• IV insulin at 4 units/hour
• Propofol 20 mg/hour
• Fentanyl 30 mcg/hour

Question 1.1 (8 marks)

Outline your immediate management of this patient.

Question 1.2 (6 marks)

Describe the physiological counter-regulatory response to hypoglycaemia and explain why this patient may have an impaired response.

Question 1.3 (6 marks)

After stabilising this patient, describe your approach to preventing further hypoglycaemic episodes.

---

Model Answer SAQ 1

Question 1.1 (8 marks total)

Immediate Management:

Stop the offending agent (1 mark)

• Immediately cease the IV insulin infusion

Administer glucose replacement (2 marks)

• Give D10 100-150 mL IV over 5-10 minutes (10-15g glucose)
• If central access available and faster response needed, can use D50 25 mL IV
• Avoid D50 via peripheral line (risk of phlebitis, extravasation injury)

Reassess clinical status (1 mark)

• Brief neurological assessment: Is the patient more responsive/improving?
• Check airway protection, breathing, circulation
• The tachycardia and borderline hypotension may be related to hypoglycaemia (sympathoadrenal response) or ongoing sepsis

Recheck glucose (1 mark)

• Repeat POC glucose in 15-30 minutes post-treatment
• Target: glucose above 5.0 mmol/L before considering further management

If hypoglycaemia persists (1 mark)

• Repeat D10 100 mL bolus
• Consider continuous D10 infusion 100-200 mL/hour
• If refractory despite dextrose, consider:
  • Glucagon 1 mg IV (less effective if glycogen depleted)
  • Hydrocortisone 100 mg IV (if adrenal insufficiency suspected)

Address precipitating cause (2 marks)

• Restart enteral nutrition immediately (it has been held for 3 hours)
• The combination of ongoing insulin + interrupted nutrition is the likely cause
• Review insulin protocol - need adjustment for patients with interrupted feeds
• Consider higher glucose threshold for insulin reinitiation

---

Question 1.2 (6 marks total)

Normal Counter-Regulatory Response (3 marks)

The counter-regulatory response is a hierarchical hormonal cascade activated at progressively lower glucose thresholds:

1. Glucagon (threshold 3.6-3.8 mmol/L)

   • Primary defence against hypoglycaemia
   • Stimulates hepatic glycogenolysis (rapid, within minutes)
   • Activates gluconeogenesis (slower, over hours)
   • Requires adequate hepatic glycogen stores

2. Adrenaline (Epinephrine) (threshold 3.4-3.6 mmol/L)

   • Second line of defence
   • Stimulates hepatic glycogenolysis
   • Inhibits peripheral glucose uptake
   • Causes autonomic symptoms (tremor, sweating, tachycardia)

3. Cortisol and Growth Hormone (threshold 3.2-3.4 mmol/L)

   • Delayed response (hours)
   • Cortisol promotes gluconeogenesis, protein catabolism
   • Growth hormone causes insulin resistance

4. Symptomatic threshold (approximately 3.0 mmol/L)

   • Autonomic symptoms (warning signals)
   • Neuroglycopenic symptoms below 2.5 mmol/L

Reasons for Impaired Response in This Patient (3 marks)

1. Critical illness/Sepsis

   • Pro-inflammatory cytokines suppress glucagon release
   • Hepatic dysfunction impairs gluconeogenesis
   • Critical illness-related corticosteroid insufficiency (CIRCI) may impair cortisol response

2. Sedation with propofol and fentanyl

   • Masks autonomic symptoms (restlessness, agitation)
   • Patient cannot communicate symptoms (hunger, confusion)
   • Altered level of consciousness prevents recognition

3. Beta-blocker therapy (if applicable)

   • Masks tachycardia and tremor
   • May impair hepatic glycogenolysis

4. Type 2 Diabetes

   • May have impaired glucagon response over time
   • Previous episodes may cause hypoglycaemia unawareness

5. Nutritional status

   • Recent major surgery and sepsis may have depleted hepatic glycogen
   • Glucagon less effective without glycogen stores

---

Question 1.3 (6 marks total)

Approach to Preventing Further Hypoglycaemic Episodes:

Protocol modification (2 marks)

• Review and adjust the insulin infusion protocol for this patient
• Consider a slightly higher lower threshold (above 7.0 mmol/L) for insulin reinitiation
• Reduce insulin rate if restarted (given this episode)
• Use a validated column-based protocol that accounts for rate of glucose change

Monitoring adjustments (1 mark)

• Increase glucose monitoring frequency to every 1-2 hours
• Continue intensive monitoring for 24 hours after hypoglycaemic episode
• Consider continuous glucose monitoring if available

Nutrition coordination (2 marks)

• Establish clear protocols for nutrition interruption:
  • If enteral feed held, reduce or stop insulin infusion
  • Document time of feed cessation and notify nursing staff
  • Restart nutrition as soon as clinically safe
  • Check glucose 30-60 minutes after nutrition interruption
• Ensure adequate caloric delivery to meet metabolic demands

Communication and documentation (1 mark)

• Incident documentation for quality improvement
• Handover to incoming staff about hypoglycaemia risk
• Involve nursing staff and dietitian in management plan
• Consider hypoglycaemia alert/flag in electronic systems

---

SAQ 2: Evidence-Based Glycemic Control

Time Allocation: 10 minutes Total Marks: 20

Stem:

You are an ICU registrar involved in updating your unit's glucose management protocol. The current protocol targets a blood glucose of 4.0-6.0 mmol/L with variable rate IV insulin. There have been several hypoglycaemic episodes in recent months.

Question 2.1 (8 marks)

Outline the evidence from randomised controlled trials regarding glycemic targets in critically ill adults.

Question 2.2 (6 marks)

Based on the evidence, what glycemic target would you recommend, and why?

Question 2.3 (6 marks)

Describe the key elements of a safe glucose management protocol to minimise hypoglycaemia while avoiding significant hyperglycaemia.

---

Model Answer SAQ 2

Question 2.1 (8 marks total)

Landmark Trials in Glycemic Control:

Van den Berghe Leuven I (2001) - PMID 11794168 (2 marks)

• Single-centre RCT, 1,548 surgical ICU patients
• Intensive control (4.4-6.1 mmol/L) vs Conventional (10-11.1 mmol/L)
• Showed reduced ICU mortality (4.6% vs 8.0%, p=0.04)
• Limitations: Single centre, predominantly cardiac surgery, high parenteral nutrition use
• Severe hypoglycaemia: 5.1% vs 0.7%

Van den Berghe Leuven II (2006) - PMID 16452557 (1 mark)

• Same group, 1,200 medical ICU patients
• No mortality benefit in intention-to-treat analysis
• Higher hypoglycaemia rate in intensive group (18.7% vs 3.1%)

VISEP Trial (2008) - PMID 18492866 (1 mark)

• Multicentre RCT, 537 severe sepsis patients
• Stopped early for hypoglycaemia (17% vs 4.1%)
• No mortality benefit
• Demonstrated harm from intensive control in sepsis

GLUCONTROL Trial (2009) - PMID 19237716 (1 mark)

• European multicentre RCT, 1,101 patients
• Intensive (4.4-6.1) vs Intermediate (7.8-10 mmol/L)
• Stopped early - severe hypoglycaemia 8.7% vs 2.7%
• No mortality difference

NICE-SUGAR Trial (2009) - PMID 19318384 (3 marks)

• Largest trial: 6,104 patients from 42 centres (Australia, NZ, Canada)
• Intensive (4.5-6.0 mmol/L) vs Conventional (below 10 mmol/L)
• Key findings:
  • 90-day mortality HIGHER with intensive control: 27.5% vs 24.9% (OR 1.14, p=0.02)
  • "Severe hypoglycaemia markedly increased: 6.8% vs 0.5% (OR 13.6)"
  • Substudy showed hypoglycaemia independently associated with mortality (OR 2.1)
• Changed practice globally - ended tight glycemic control era

Meta-analyses confirm:

• No mortality benefit for intensive control (RR 1.04)
• 6-fold increase in severe hypoglycaemia risk

---

Question 2.2 (6 marks total)

Recommended Glycemic Target (2 marks)

Based on current evidence, I would recommend a target range of 6-10 mmol/L (108-180 mg/dL) for most critically ill patients.

Rationale (4 marks)

1. Avoids harm from hypoglycaemia

   • NICE-SUGAR demonstrated 2.1-fold increased mortality with severe hypoglycaemia
   • Lower threshold of 6.0 mmol/L provides safety margin
   • Aligns with counter-regulatory activation threshold (approximately 3.8 mmol/L)

2. Avoids harm from hyperglycaemia

   • Upper limit of 10 mmol/L prevents extreme hyperglycaemia
   • Evidence suggests glucose above 10-12 mmol/L associated with increased infection, poor wound healing, and possibly mortality

3. Reduces glucose variability

   • Wider target range allows more stable glucose control
   • Less frequent insulin adjustments
   • Variability independently associated with mortality

4. Guideline concordance

   • Surviving Sepsis Campaign 2021: 6-10 mmol/L
   • ANZICS/CICM recommendations: 6-10 mmol/L
   • ADA/AACE: 7.8-10 mmol/L (slightly more conservative lower limit)

5. Practical considerations

   • Achievable with standard nursing workload
   • Less intensive monitoring required than tight control
   • Lower insulin doses reduce hypoglycaemia risk

---

Question 2.3 (6 marks total)

Key Elements of a Safe Glucose Management Protocol:

1. Validated Protocol Structure (1 mark)

• Use a published, validated protocol (e.g., modified Yale, Portland)
• Column-based design with clear dose adjustment algorithms
• Consider both absolute glucose AND rate of change

2. Appropriate Glucose Thresholds (1 mark)

• Initiate insulin when glucose above 10 mmol/L (confirmed on 2 readings)
• Stop insulin when glucose below 6.0 mmol/L
• Treat hypoglycaemia (below 4.0 mmol/L) with standardised dextrose protocol

3. Monitoring Schedule (1 mark)

• Every 1-2 hours during active insulin titration
• Every 4 hours when stable in target range
• Immediate recheck after any dextrose administration
• More frequent monitoring for high-risk patients (liver failure, RRT)

4. Nutrition Integration (1 mark)

• Clear instructions for insulin management when nutrition interrupted
• Reduce or stop insulin if enteral/parenteral nutrition held
• Automatic glucose check 30-60 minutes after nutrition cessation
• Restart insulin cautiously after nutrition resumed

5. High-Risk Patient Identification (1 mark)

• Flag patients at increased hypoglycaemia risk:
  • Hepatic failure
  • Renal failure (especially on dialysis)
  • Sepsis with improving clinical status
  • Recent steroid cessation
  • Elderly, malnourished
• Consider modified targets or more intensive monitoring

6. Quality Improvement Mechanisms (1 mark)

• Incident reporting for all hypoglycaemic episodes
• Regular audit of protocol adherence and outcomes
• Feedback to staff on hypoglycaemia rates
• Clear escalation pathway for refractory hypoglycaemia
• Documentation requirements for all glucose management decisions

---

Hot Case Scenarios

Hot Case 1: Hypoglycaemia in Septic Shock

Setting: ICU Bed 6 Duration: 20 minutes (10 min assessment + 10 min discussion) Equipment: Ventilator, monitors, IV pumps, charts available

---

Actor/Simulator Briefing (Not given to candidate):

Patient Details:

• Age: 58 years
• Gender: Male
• Admission diagnosis: Community-acquired pneumonia with septic shock
• Day of ICU stay: Day 4

History:

• Type 2 diabetes on metformin and glargine insulin (40 units daily)
• Hypertension on ramipril
• Ex-smoker
• Admitted via ED with severe CAP, required intubation Day 1
• Required noradrenaline up to 0.3 mcg/kg/min, now weaned to 0.08 mcg/kg/min
• IV insulin infusion for hyperglycaemia (initially glucose 18 mmol/L)

Examination Findings:

• General: Intubated, sedated (RASS -2), diaphoretic
• Airway: ETT in situ, position 22cm at lips
• Breathing: Bilateral coarse crackles, ventilator SIMV PS, FiO2 0.35
• Circulation: Cool peripheries, CRT 3 seconds, HR 115 regular, JVP not elevated
• Disability: Pupils equal and reactive, GCS E1VtM4 (5T)
• Lines: Right IJ CVC, left radial arterial line, IDC, NGT

Current Observations:

• HR: 115 bpm
• BP: 88/52 mmHg (MAP 64)
• RR: 16 (ventilated)
• SpO2: 96%
• Temp: 37.8 degrees C

Current Infusions:

• Noradrenaline 0.08 mcg/kg/min
• Propofol 30 mg/hr
• Fentanyl 50 mcg/hr
• IV insulin 6 units/hour

Latest Results:

• Glucose: 2.4 mmol/L (just performed by nurse)
• Previous glucose (2 hours ago): 8.2 mmol/L
• ABG: pH 7.38, PCO2 36, PO2 95, HCO3 21, Lac 1.8, Na 138, K 4.2
• CRP: 180 (down from 320)
• Creatinine: 145 (was 220)

Feeding:

• Enteral nutrition running at 50 mL/hr (target rate)
• NGT aspirates low

---

Expected Performance:

Assessment Phase (10 minutes) - 15 marks

History (3 minutes) - 3 marks:

Must establish:

• Current glucose level and trend (2.4 now, was 8.2 two hours ago - rapid drop)
• Insulin infusion details (rate, recent adjustments)
• Nutrition status (feeding rate, any interruptions)
• Any recent changes in clinical status (improving sepsis)
• Diabetes history and home medications
• Any symptoms noted by nursing staff (diaphoresis)

Examination (7 minutes) - 10 marks:

Airway (1 mark):

• ETT position and patency
• Cuff pressure

Breathing (2 marks):

• Ventilator settings and patient effort
• Chest examination (note improvement from pneumonia)
• SpO2 trajectory

Circulation (3 marks):

• Note diaphoresis (possible adrenergic response to hypoglycaemia)
• Tachycardia (HR 115 - may be adrenergic response)
• Borderline MAP (64) despite low-dose noradrenaline
• Perfusion status (cool peripheries, CRT 3 sec - may be contributing)

Disability (2 marks):

• Assess GCS/RASS
• Note any seizure activity
• Pupils (for other causes of reduced consciousness)
• Check glucose meter (confirm value)

Exposure (1 mark):

• Temperature, skin examination
• Review lines for potential source control

Charts Review (1 mark):

• Glucose trend over past 24 hours
• Insulin infusion rate changes
• Nutrition record
• Improving inflammatory markers
• Improving renal function

One-Minute Summary (1 minute) - 2 marks:

"This is a 58-year-old male, Day 4 of ICU admission for severe community-acquired pneumonia with septic shock, now recovering. He is currently ventilated on SIMV with improving oxygenation and has been weaning from noradrenaline. He has been on IV insulin for hyperglycaemia but has just developed severe hypoglycaemia of 2.4 mmol/L despite stable enteral feeding. His tachycardia and diaphoresis may be related to hypoglycaemia. Immediate priorities are: (1) cease insulin infusion, (2) administer IV dextrose, (3) recheck glucose, and (4) investigate cause of rapid glucose drop."

---

Discussion Phase (10 minutes) - 15 marks

Opening Question: "What is your immediate management?"

Expected Answer (3 marks):

1. Stop insulin infusion immediately
2. Administer D10 100-150 mL IV bolus (or D50 25 mL if central access available)
3. Confirm nutrition is still running
4. Recheck glucose in 15 minutes
5. Continue noradrenaline (MAP borderline, septic shock still present)

Follow-up Question 1: "Why might this patient have developed hypoglycaemia?" (3 marks)

Expected Answer:

• Improving sepsis - insulin sensitivity increases as sepsis resolves
• Improving renal function - creatinine dropping, insulin clearance increasing
• Counter-regulatory hormone impairment from critical illness
• Possible relative adrenal insufficiency (consider CIRCI given ongoing vasopressor need)
• Insulin rate may have been too high for current metabolic state
• Type 2 diabetes on background insulin - residual endogenous capacity

Follow-up Question 2: "The glucose remains 3.1 mmol/L after one bolus of D10. What do you do now?" (3 marks)

Expected Answer:

• Repeat D10 100 mL bolus
• Consider starting continuous D10 infusion at 100-200 mL/hr
• Recheck glucose every 15-30 minutes until above 5.0 mmol/L
• Consider hydrocortisone 100 mg IV if refractory (CIRCI)
• Consider glucagon 1 mg IV if no IV access (but less effective in critical illness)
• Ensure nutrition continues

Follow-up Question 3: "Tell me about the evidence for glycemic targets in critical illness." (3 marks)

Expected Answer:

• Van den Berghe 2001: Initial evidence for tight control (4.4-6.1 mmol/L), reduced mortality in surgical ICU
• NICE-SUGAR 2009: Largest trial (6,104 patients), showed increased mortality with tight control
• Severe hypoglycaemia 6.8% vs 0.5%, associated with 2.1-fold mortality increase
• Current target: 6-10 mmol/L (SSC 2021, ANZICS)
• Focus on avoiding both hypoglycaemia and extreme hyperglycaemia
• Glucose variability also independently associated with mortality

Follow-up Question 4: "This patient is Aboriginal Australian. What specific considerations apply?" (3 marks)

Expected Answer:

• Higher rates of Type 2 diabetes and diabetic complications in Aboriginal population
• May have delayed presentation with more severe illness
• Consider cultural and family involvement in care decisions
• Engage Aboriginal Health Worker/Liaison Officer
• Consider remote residence affecting follow-up care
• Ensure discharge planning includes diabetes education and access to medications
• Language and health literacy considerations
• Historical factors affecting trust in healthcare system

---

Hot Case 2: Hepatic Failure with Spontaneous Hypoglycaemia

Setting: ICU Bed 12 Duration: 20 minutes (10 min assessment + 10 min discussion)

---

Actor/Simulator Briefing (Not given to candidate):

Patient Details:

• Age: 34 years
• Gender: Female
• Admission diagnosis: Paracetamol overdose with acute liver failure
• Day of ICU stay: Day 2

History:

• Ingested 48g paracetamol in intentional overdose
• Presented 18 hours post-ingestion
• NAC commenced in ED, liver function deteriorating
• Intubated for Grade III hepatic encephalopathy
• No diabetes mellitus, no insulin given

Examination Findings:

• General: Jaundiced, intubated, no sedation running
• Airway: ETT in situ, position 21cm
• Breathing: Clear air entry, CPAP 5/5, FiO2 0.3
• Circulation: Warm peripheries, HR 98 regular, BP 95/58
• Disability: GCS E1VtM2 (3T off sedation), pupils 4mm sluggishly reactive
• Abdomen: Soft, liver edge not palpable, no ascites

Current Observations:

• HR: 98 bpm
• BP: 95/58 mmHg
• RR: 20 (spontaneous on CPAP)
• SpO2: 99%
• Temp: 36.2 degrees C

Latest Results:

• Glucose: 2.8 mmol/L (no insulin being given)
• Previous glucose (4 hours ago): 4.2 mmol/L
• ABG: pH 7.32, PCO2 28, PO2 145, HCO3 14, Lac 8.5
• INR: 6.2, Fibrinogen 0.8 g/L
• Bilirubin: 280 umol/L, ALT: 8500, AST: 9200
• Creatinine: 185
• Ammonia: 145 umol/L

---

Expected Performance:

Assessment and Discussion Focus:

Key Findings:

• Spontaneous hypoglycaemia (no exogenous insulin) indicates severe hepatic synthetic failure
• Fulfils King's College Criteria for paracetamol overdose (INR above 6, Grade III encephalopathy, creatinine above 180)
• This is an emergency liver transplant listing consideration

Immediate Management:

1. D10 100 mL IV bolus for hypoglycaemia
2. Start continuous D10 infusion at 100-150 mL/hr
3. Monitor glucose every 1-2 hours
4. Continue NAC infusion
5. Urgent contact with liver transplant centre

Hypoglycaemia Mechanism in Liver Failure:

• Depleted hepatic glycogen stores (glycogenolysis ineffective)
• Impaired gluconeogenesis (primary hepatic function)
• Glucagon cannot stimulate glucose production
• Reduced insulin clearance (but minimal insulin present)
• Hypoglycaemia is a poor prognostic indicator reflecting loss of metabolic function

Further Management:

• This patient needs urgent transplant assessment
• Continuous dextrose infusion often required (10-20 g/hour)
• May need D20 or D50 infusion via central line to limit volume
• Monitor and treat other consequences of liver failure (coagulopathy, cerebral oedema, renal failure, infection)

---

Viva Questions

Viva 1: Counter-Regulatory Physiology

Stem:

"A 45-year-old male is Day 2 in ICU following a coronary artery bypass graft. He has been on an IV insulin infusion targeting blood glucose 6-10 mmol/L. The nurse alerts you that his glucose is 2.5 mmol/L."

Opening Question:

"Describe the normal physiological response to hypoglycaemia."

Expected Answer (2-3 minutes):

The counter-regulatory response to hypoglycaemia is a hierarchical hormonal cascade designed to restore glucose homeostasis and prevent neuroglycopenia:

Threshold 3.6-3.8 mmol/L - Glucagon:

• First line of defence
• Secreted from pancreatic alpha cells
• Stimulates hepatic glycogenolysis (rapid - within minutes)
• Activates gluconeogenesis (slower - over hours)
• Also inhibits insulin secretion

Threshold 3.4-3.6 mmol/L - Adrenaline (Epinephrine):

• Released from adrenal medulla
• Stimulates hepatic glucose output (glycogenolysis, gluconeogenesis)
• Inhibits peripheral glucose uptake
• Stimulates lipolysis (alternative fuel source)
• Causes characteristic autonomic symptoms

Threshold 3.2-3.4 mmol/L - Cortisol and Growth Hormone:

• Cortisol promotes gluconeogenesis, protein catabolism for substrates
• Growth hormone causes insulin resistance
• Delayed response (hours rather than minutes)

Threshold approximately 3.0 mmol/L - Symptoms:

• Autonomic: Sweating, tremor, palpitations, anxiety, hunger
• Neuroglycopenic: Confusion, drowsiness, visual disturbance

Threshold below 2.5 mmol/L:

• Seizures, coma, potentially death
• Brain cannot maintain function without glucose

---

Follow-up Question 1:

"Why might this post-cardiac surgery patient have an impaired counter-regulatory response?"

Expected Answer:

Several factors may impair counter-regulatory responses post-cardiac surgery:

1. Sedation and anaesthesia - Masks symptoms, prevents recognition and communication

2. Beta-blocker therapy - Often used post-CABG for rate control and cardioprotection; blocks catecholamine-mediated symptoms (tremor, tachycardia) and may impair glycogenolysis

3. Prior hypoglycaemic episodes - May have had earlier unrecognised hypoglycaemia causing hypoglycaemia-associated autonomic failure (HAAF)

4. Hypothermia from bypass - Alters metabolic rate and hormone responses

5. Inflammatory state - Cardiopulmonary bypass induces systemic inflammation (SIRS), which can impair adrenal axis function

6. Potential adrenal suppression - If received perioperative steroids

7. Relative adrenal insufficiency - Stress response may be inadequate

---

Follow-up Question 2:

"How would you treat this patient's hypoglycaemia?"

Expected Answer:

Immediate actions:

1. Stop the insulin infusion immediately
2. Administer D10 100-150 mL IV over 5-10 minutes (provides 10-15g glucose)
3. Alternatively, D50 25 mL via central line if faster response needed
4. Recheck glucose in 15 minutes

If hypoglycaemia persists:

• Repeat D10 bolus
• Consider continuous D10 infusion at 100-200 mL/hr
• Glucagon 1 mg IV/IM (should be effective post-cardiac surgery as liver glycogen likely intact)

Further management:

• Review insulin protocol before restarting
• Consider a lower target or reduced starting dose
• Ensure adequate nutrition
• Monitor glucose every 1-2 hours until stable
• Document incident for quality improvement

---

Follow-up Question 3:

"What is the evidence regarding glucose targets in ICU patients, and why is hypoglycaemia harmful?"

Expected Answer:

Evidence for Glucose Targets:

The NICE-SUGAR trial (2009, PMID 19318384) compared intensive (4.5-6.0 mmol/L) versus conventional (below 10 mmol/L) glucose control in 6,104 patients. Key findings:

• 90-day mortality was higher with intensive control (27.5% vs 24.9%, OR 1.14)
• Severe hypoglycaemia (below 2.2 mmol/L) occurred in 6.8% intensive vs 0.5% conventional
• Substudy showed hypoglycaemia independently associated with 2.1-fold increased mortality

Current recommendation is target 6-10 mmol/L.

Why Hypoglycaemia is Harmful:

1. Neurological injury:

   • Brain is obligate glucose user (120g/day)
   • Minimal glycogen reserves (1-2 min)
   • Neuronal death in cortex, hippocampus, caudate with prolonged hypoglycaemia
   • Excitotoxicity from glutamate release

2. Cardiovascular effects:

   • Catecholamine surge increases myocardial oxygen demand
   • QTc prolongation (arrhythmia risk)
   • Platelet activation
   • Particularly concerning in cardiac surgery patients

3. Inflammatory response:

   • Pro-inflammatory cytokine release
   • Oxidative stress
   • Endothelial dysfunction

---

Viva 2: Hypoglycaemia in Hepatic Failure

Stem:

"A 52-year-old male with known cirrhosis (Child-Pugh C) is admitted with spontaneous bacterial peritonitis. He is Day 3 in ICU, improving on ceftriaxone. However, over the past 24 hours he has had three hypoglycaemic episodes despite not receiving any insulin."

Opening Question:

"Why is this patient at risk of spontaneous hypoglycaemia?"

Expected Answer (2-3 minutes):

Patients with advanced liver disease are at high risk of spontaneous hypoglycaemia due to impaired hepatic glucose homeostasis:

1. Depleted Glycogen Stores:

• The liver stores approximately 100g of glycogen normally
• Cirrhosis results in reduced hepatic mass and impaired glycogen storage
• Glycogen stores in cirrhosis may be depleted within 12-24 hours of fasting
• Glucagon stimulates glycogenolysis but cannot produce glucose if glycogen absent

2. Impaired Gluconeogenesis:

• The liver is the primary site of gluconeogenesis (80%)
• Substrates: lactate, alanine, glycerol
• Enzymes for gluconeogenesis (PEPCK, G6Pase) may be downregulated
• Reduced hepatic blood flow limits substrate delivery
• This is the major mechanism in chronic liver disease

3. Impaired Counter-Regulatory Hormones:

• Glucagon release may be reduced
• Cortisol response may be impaired
• "Relative adrenal insufficiency" described in cirrhosis

4. Reduced Insulin Clearance:

• However, insulin is not the main driver (no exogenous insulin)
• Endogenous insulin levels are often elevated in cirrhosis due to reduced clearance

5. Sepsis Contribution:

• SBP adds inflammatory burden
• Cytokines further impair gluconeogenesis
• Increased peripheral glucose consumption
• Possible adrenal dysfunction

6. Nutritional Status:

• Protein-calorie malnutrition common in Child-C cirrhosis
• Reduced amino acid substrates for gluconeogenesis

---

Follow-up Question 1:

"How would you manage the recurrent hypoglycaemia in this patient?"

Expected Answer:

Immediate Treatment of Each Episode:

• D10 100-150 mL IV bolus when glucose below 4.0 mmol/L
• Recheck in 15 minutes

Prevention Strategy:

1. Continuous dextrose infusion:

   • D10 at 100-200 mL/hr (10-20 g glucose/hour)
   • May need D20 via central line if fluid restricted
   • Titrate to maintain glucose above 5.0 mmol/L

2. Frequent monitoring:

   • Check glucose every 2-4 hours minimum
   • Consider continuous glucose monitoring if available

3. Optimise nutrition:

   • Start enteral feeding early if possible
   • Frequent small feeds to prevent prolonged fasting
   • May need nocturnal feed to prevent overnight hypoglycaemia
   • High carbohydrate content

4. Treat underlying cause:

   • Continue SBP treatment
   • Address any other precipitants of decompensation

5. Glucagon is NOT effective:

   • Glycogen stores depleted
   • Gluconeogenesis impaired
   • Do not rely on glucagon in liver failure

6. Consider glucocorticoids if refractory:

   • Relative adrenal insufficiency may contribute
   • Hydrocortisone 100 mg IV may help

---

Follow-up Question 2:

"What is the prognostic significance of hypoglycaemia in acute liver failure?"

Expected Answer:

Spontaneous hypoglycaemia in acute liver failure is a poor prognostic indicator that reflects severe loss of hepatic synthetic and metabolic function.

King's College Criteria (Paracetamol):

• Hypoglycaemia is not a standalone criterion, but reflects metabolic failure
• Key criteria: pH below 7.3, OR INR above 6.5 + creatinine above 300 + Grade III/IV encephalopathy

Hypoglycaemia indicates:

• Loss of gluconeogenic capacity (major hepatic function)
• Depleted glycogen stores
• Correlates with severity of hepatocellular injury
• Often accompanies other synthetic failures (coagulopathy, ammonia elevation)

Management implications:

• Early contact with liver transplant centre
• May indicate need for liver transplant assessment
• Continue supportive care while awaiting possible transplant
• Maintain glucose with continuous dextrose infusion

---

Viva 3: Indigenous Health Considerations

Stem:

"You are the ICU consultant in a regional hospital in Far North Queensland. An Aboriginal man aged 48 with Type 2 diabetes has been admitted with diabetic ketoacidosis and sepsis secondary to a foot ulcer. He is Day 2 in your unit and has had two hypoglycaemic episodes overnight while on an insulin infusion."

Opening Question:

"What factors contribute to the higher burden of diabetic emergencies in Aboriginal and Torres Strait Islander communities?"

Expected Answer (2-3 minutes):

Aboriginal and Torres Strait Islander peoples experience 3-4 times higher rates of diabetes and significantly higher rates of diabetic emergencies due to multiple interacting factors:

1. Biological/Genetic Factors:

• "Thrifty gene" hypothesis - adapted for feast/famine cycles
• Higher rates of insulin resistance
• Earlier onset of Type 2 diabetes
• More rapid progression to complications

2. Social Determinants of Health:

• Lower socioeconomic status on average
• Limited access to healthy, affordable food (especially in remote areas)
• Higher rates of food insecurity
• Overcrowded housing
• Lower educational attainment affecting health literacy

3. Healthcare Access Barriers:

• Distance to services (particularly in remote communities)
• Lack of transport
• Shortage of culturally appropriate healthcare workers
• Historical distrust of healthcare system (Stolen Generations, past discrimination)
• Lack of continuity of care

4. System Factors:

• Under-representation in health workforce
• Services not designed for cultural appropriateness
• Language barriers (English may be second/third language)
• Lack of diabetes education resources in language

5. Lifestyle Factors:

• Diet transition from traditional to Western foods
• Reduced physical activity
• Higher rates of smoking
• Higher rates of alcohol use in some communities

6. Complications:

• Higher rates of renal disease (dialysis-dependent)
• Higher rates of cardiovascular disease
• Higher amputation rates
• More severe infections at presentation

---

Follow-up Question 1:

"How would you modify your approach to managing this patient's hypoglycaemia?"

Expected Answer:

Immediate Medical Management (same principles):

• Treat hypoglycaemia with D10 100-150 mL IV
• Stop/reduce insulin appropriately
• Increase glucose monitoring frequency
• Review protocol

Culturally Appropriate Modifications:

1. Involve Aboriginal Health Worker/Liaison Officer:

   • Essential member of care team
   • Can assist with communication
   • Bridge between family and healthcare team
   • Understanding of cultural context

2. Family/Community Involvement:

   • Extended family may want to be present
   • Decision-making may be collective
   • Allow time and space for family discussions
   • Respect community Elder input

3. Communication:

   • Use professional interpreter if language barrier
   • Avoid medical jargon
   • Check understanding (not just "do you understand?")
   • Visual aids may be helpful
   • Slower pace of discussion

4. Respect Cultural Practices:

   • Traditional medicine may be used alongside Western medicine
   • Spiritual and cultural needs (sorry business, community obligations)
   • Privacy preferences may differ

5. Discharge Planning:

   • What medications can patient actually access?
   • Is there a pharmacy in their community?
   • Refrigeration for insulin?
   • Follow-up arrangements
   • Link with community health services
   • Consider Closing the Gap PBS provisions

---

Follow-up Question 2:

"How can ICU services better address health equity for Indigenous patients?"

Expected Answer:

Systemic Improvements:

1. Workforce:

   • Recruit and retain Indigenous staff
   • Cultural competency training for all staff (mandatory)
   • Employment of Aboriginal Health Workers/Liaison Officers
   • Support for Indigenous health professional training

2. Clinical Processes:

   • Identify Indigenous patients at admission (not just for statistics - for care)
   • Standard prompts to involve AHW/ALO
   • Discharge planning starts early with community health
   • Access to interpreters 24/7

3. Environment:

   • Culturally appropriate spaces (natural light, artwork, outdoor access)
   • Family accommodation and support
   • Flexibility in visiting policies

4. Partnerships:

   • Work with Aboriginal Community Controlled Health Organisations
   • Outreach to remote communities
   • Telehealth for ongoing support
   • Collaborative models of care

5. Measurement and Accountability:

   • Track Indigenous patient outcomes
   • Quality improvement initiatives targeting disparities
   • Indigenous representation on governance/advisory committees

---

Viva 4: Protocol Development

Stem:

"You have been asked by your ICU Director to review and update your unit's glucose management protocol following several hypoglycaemic events. The current protocol targets 4.0-6.0 mmol/L."

Opening Question:

"What elements would you include in a safe, evidence-based glucose management protocol?"

Expected Answer (2-3 minutes):

A safe glucose management protocol should include:

1. Evidence-Based Target Range:

• Target 6-10 mmol/L (per NICE-SUGAR, SSC 2021)
• Initiate insulin when glucose above 10 mmol/L on 2 consecutive readings
• Stop/reduce insulin when glucose below 6.0 mmol/L

2. Validated Insulin Algorithm:

• Column-based protocol with clear dose adjustment rules
• Consider both absolute glucose AND rate of change
• Published/validated protocols (Yale, Portland, SPRINT modifications)
• Starting dose typically 1-2 units/hour

3. Monitoring Schedule:

• Every 1-2 hours during active titration
• Every 4 hours when stable
• Immediate recheck after dextrose treatment
• More frequent in high-risk patients

4. Hypoglycaemia Treatment Protocol:

• Clear definition (below 4.0 mmol/L)
• Standardised treatment (D10 100-150 mL)
• Stop insulin if glucose below 4.0 mmol/L
• Recheck glucose 15 min post-treatment
• Escalation pathway for refractory hypoglycaemia

5. Nutrition Integration:

• Clear instructions when feeds held
• Automatic glucose check when nutrition interrupted
• Reduce/stop insulin if feeding stopped
• Resume insulin cautiously when feeding restarts

6. High-Risk Patient Identification:

• Hepatic failure, renal failure, sepsis, elderly
• Modified monitoring or targets for high-risk patients
• Alert/flag system

7. Documentation Requirements:

• Glucose flowsheet
• Insulin infusion rate changes with rationale
• Hypoglycaemia incident documentation

8. Quality Improvement:

• Regular audit of hypoglycaemia rates
• Incident reporting system
• Feedback to staff
• Protocol review cycle

---

Follow-up Question 1:

"How would you implement this protocol change in your unit?"

Expected Answer:

Pre-Implementation:

1. Form a multidisciplinary working group (intensivists, nurses, pharmacists, endocrinology)
2. Review current performance data (hypoglycaemia rates, glucose control metrics)
3. Draft protocol based on evidence and best practice
4. Pilot test on small patient group
5. Refine based on feedback

Education:

1. In-service training for all nursing staff
2. Medical staff orientation
3. Written reference guides
4. Competency assessment

Implementation:

1. Set go-live date with sufficient lead time
2. Champions on each shift during rollout
3. Clear documentation of protocol
4. Easy access (laminated, electronic)

Post-Implementation:

1. Monitoring of key metrics (hypoglycaemia rate, time in range)
2. Collect feedback from staff
3. Regular audit and feedback cycles
4. Protocol modifications based on local data
5. Ongoing education for new staff

---

Viva 5: Neurocritical Care and Hypoglycaemia

Stem:

"A 35-year-old female is Day 1 post severe traumatic brain injury (TBI) with GCS 7T. She has been on an insulin infusion and a routine glucose check shows 3.2 mmol/L."

Opening Question:

"Why is hypoglycaemia particularly harmful for the injured brain?"

Expected Answer (2-3 minutes):

The injured brain is exquisitely vulnerable to hypoglycaemia for several reasons:

1. Obligate Glucose Dependence:

• Brain consumes approximately 120g glucose per day (20% of total body use)
• Minimal glycogen reserves (sufficient for 1-2 minutes)
• Cannot efficiently use alternative fuels acutely (ketones require adaptation)
• Blood-brain barrier limits alternative fuel entry

2. Increased Metabolic Demand Post-TBI:

• Hypermetabolism in acute phase
• Increased glucose consumption in perilesional tissue
• Glucose demand may exceed supply even at "normal" blood glucose

3. Impaired Autoregulation:

• Cerebral autoregulation often disrupted after TBI
• Brain cannot maintain constant cerebral blood flow
• Hypoglycaemia may compound ischemia in injured tissue

4. Cerebral Microdialysis Studies Show:

• Low brain glucose correlates with worse outcomes
• Periods of "cerebral hypoglycaemia" (extracellular glucose below 0.7 mmol/L) associated with worse outcome
• Can occur despite "adequate" systemic glucose

5. Secondary Injury Cascade:

• Hypoglycaemia causes ATP depletion
• Excitotoxic neuronal death (glutamate release)
• Oxidative stress
• Cellular oedema
• Exacerbates primary injury

6. Impaired Counter-Regulation:

• Hypothalamic-pituitary injury may impair counter-regulatory hormone responses
• Sedation masks symptoms
• GCS monitoring confounded by injury

---

Follow-up Question 1:

"What glucose targets would you recommend for this patient?"

Expected Answer:

Recommended Target: 7-10 mmol/L (some guidelines 8-10 mmol/L)

Rationale:

• Higher lower limit (7 rather than 6 mmol/L) provides greater safety margin for the injured brain
• Avoids hypoglycaemia which can worsen secondary injury
• Upper limit prevents severe hyperglycaemia (also harmful - increased cerebral oedema, oxidative stress)

Evidence:

• Brain Trauma Foundation guidelines recommend avoiding hypoglycaemia
• No consensus on optimal target, but general agreement to avoid glucose below 5.0 mmol/L
• Some centres use continuous glucose monitoring with stricter lower alarms

Implementation:

• More intensive monitoring (every 1-2 hours)
• Consider continuous glucose monitoring
• Lower insulin doses, more cautious titration
• Ensure adequate nutrition
• Stop insulin earlier (when glucose below 8 mmol/L rather than 6 mmol/L)

---

Follow-up Question 2:

"How would you manage her hypoglycaemia now?"

Expected Answer:

Immediate Management:

1. Stop insulin infusion immediately
2. Administer D10 100-150 mL IV over 5-10 minutes
3. Recheck glucose in 15 minutes
4. Target glucose above 7.0 mmol/L before resuming insulin

Additional Considerations in TBI:

• Ensure adequate cerebral perfusion (MAP target, CPP monitoring)
• If ICP monitored, check for any correlation with hypoglycaemia/treatment
• Maintain PaO2 adequate (hypoxia + hypoglycaemia is disastrous)
• More aggressive treatment threshold (treat even at 4.0 mmol/L in TBI)
• More frequent monitoring (every 1 hour) until stable above 7 mmol/L

If refractory:

• Continuous D10 infusion
• Consider hydrocortisone if adrenal/pituitary injury suspected
• May need higher glucose target (8-10 mmol/L)

---

Viva 6: Glucose Variability

Stem:

"You are reviewing the glucose data for a patient on your ICU. Over the past 24 hours, their glucose values have ranged from 3.8 to 18.2 mmol/L."

Opening Question:

"What is glucose variability and why is it clinically important?"

Expected Answer (2-3 minutes):

Definition: Glucose variability refers to the fluctuations in blood glucose levels over time. It can be quantified using several metrics:

1. Standard Deviation (SD): Simple measure of spread around the mean
2. Coefficient of Variation (CV): SD/Mean × 100% - normalised for mean glucose
3. Mean Amplitude of Glycemic Excursions (MAGE): Average of significant (above 1 SD) glucose swings
4. Time in Range (TIR): Percentage of time glucose is within target

Clinical Importance:

1. Independent Mortality Association:

   • Meta-analyses show glucose variability independently predicts mortality
   • OR approximately 1.4-1.8 per SD increase in variability
   • Independent of mean glucose and hypoglycaemia
   • Applies to both diabetic and non-diabetic patients

2. Pathophysiological Mechanisms:

   • Oscillating glucose causes more oxidative stress than stable high glucose
   • Endothelial dysfunction
   • Pro-inflammatory cytokine release
   • Platelet activation
   • Cell death in vitro with oscillating glucose

3. Reflects Illness Severity:

   • High variability may reflect metabolic instability
   • Sicker patients have less "metabolic reserve" to maintain homeostasis
   • Also reflects challenges in achieving stable glucose control

4. Clinical Implications:

   • Not just mean glucose or avoiding hypoglycaemia - variability matters
   • Protocols should minimise "hunting" (overcorrection swings)
   • Continuous glucose monitoring can reduce variability
   • More frequent monitoring may help if CGM not available

---

Follow-up Question 1:

"What might be causing this patient's glucose variability?"

Expected Answer:

Multiple factors likely contributing:

Patient Factors:

• Underlying illness with metabolic instability
• Sepsis with changing insulin sensitivity
• Variable nutrition delivery (feeds held for procedures)
• Steroid administration (may have variable timing/dose)
• Renal function fluctuations (affecting insulin clearance)
• Improving or worsening clinical status

Protocol/Care Factors:

• Aggressive insulin dosing swinging between over- and under-treatment
• Inconsistent monitoring intervals
• Not accounting for rate of change
• Nutrition not coordinated with insulin
• Different staff with different approaches

Iatrogenic:

• Glucose correction causing rebound hyperglycaemia
• D50 boluses (large glucose swings)
• Not reducing insulin when glucose dropping rapidly

---

Follow-up Question 2:

"How would you reduce glucose variability in this patient?"

Expected Answer:

Protocol Adjustments:

1. Target narrower effective range (6-10 mmol/L with more gradual adjustments)
2. Account for rate of change in dosing decisions
3. Smaller, more frequent insulin adjustments rather than large changes
4. Pre-emptive dose reductions when glucose dropping

Monitoring:

1. Increase monitoring frequency (every 1-2 hours if highly variable)
2. Consider continuous glucose monitoring if available
3. Track variability metrics (CV) as quality indicator

Nutrition Coordination:

1. Avoid interrupting nutrition where possible
2. When feeds held, proactive insulin reduction
3. Resume insulin cautiously after nutrition restarted
4. Continuous feeding preferred over bolus feeds

Glucose Correction:

1. Use D10 rather than D50 for treatment of hypoglycaemia
2. Avoid overcorrection
3. Don't immediately restart high-dose insulin after hypoglycaemia

Staff Education:

1. Consistent approach across nursing staff
2. Understanding of variability concept
3. Handover of glucose trends

---

Interactive Elements

[INTERACTIVE: Glucose Management Calculator]

Scenario: Calculate glucose correction dose and monitoring requirements

Patient Parameters:

• Weight: [___] kg
• Current glucose: [___] mmol/L
• Previous glucose (2 hours ago): [___] mmol/L
• Current insulin rate: [___] units/hour

Outputs:

• Rate of glucose change
• Recommended action (continue, increase, decrease, stop insulin)
• Dextrose dose if hypoglycaemic
• Next glucose check time

---

[INTERACTIVE: Insulin Infusion Simulator]

Scenario: Variable-rate insulin infusion titration

Starting conditions:

• Glucose: 15.2 mmol/L
• Target: 6-10 mmol/L
• Patient: Septic shock, on noradrenaline

Actions available:

• Start insulin at chosen rate
• Adjust rate based on glucose checks
• Respond to hypoglycaemia
• Manage nutrition interruption

Scoring:

• Time to target
• Hypoglycaemia episodes
• Glucose variability (CV)
• Protocol adherence

---

[INTERACTIVE: ABG Interpreter - Hypoglycaemia Case]

Case: Patient with altered consciousness

ABG Results:

• pH: 7.45
• PaCO2: 32 mmHg
• PaO2: 95 mmHg (RA)
• HCO3: 22 mmol/L
• Lactate: 0.8 mmol/L
• Glucose: 1.8 mmol/L
• K: 3.2 mmol/L

Interpretation Quiz:

1. What is the primary metabolic abnormality?
2. What is the most likely cause of altered consciousness?
3. What is your immediate management?