Syringe Drivers (CSCI)

1. Clinical Overview

Summary

A Syringe Driver, clinically known as Continuous Subcutaneous Infusion (CSCI), is a portable, battery-operated electromechanical pump that delivers medication continuously into the subcutaneous tissue over 24 hours. The standard device in the UK is the McKinley T34 (green) and McKinley T34 LCP models. In palliative care, CSCI is the mainstay of symptom control when the oral route is no longer viable, typically in the last days to weeks of life. [1,2]

The device provides constant plasma drug levels, avoiding the peaks and troughs associated with intermittent dosing. This is particularly important for maintaining comfort and symptom control in patients who cannot swallow, have persistent nausea/vomiting, malabsorption, intestinal obstruction, or are too weak or comatose to take oral medications. [3]

CSCI is used in over 60% of cancer deaths in the UK and is increasingly utilized in non-malignant terminal conditions including heart failure, chronic obstructive pulmonary disease (COPD), motor neurone disease, and advanced dementia. [4,5]

Key Clinical Message

The syringe driver is NOT an end-of-life trigger but a pragmatic solution to maintain comfort when the oral route fails. The doses used are equivalent to (or often lower than) previous oral doses when properly converted. Evidence consistently demonstrates that CSCI does not hasten death but ensures dignified symptom control. [6]

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2. Epidemiology

Utilization Statistics

Demographics

• Age: Predominantly used in patients >65 years (70% of cases).
• Setting: 55% hospice, 30% home, 15% hospital.
• Duration: Median duration of use 5-7 days (range 1-30+ days). [7]
• Timing: Typically commenced 7-14 days before death in cancer patients.

Trends

The use of CSCI has increased 30% over the past decade, driven by:

1. Improved community palliative care services.
2. Greater acceptance of subcutaneous route for hydration and medication.
3. Development of compatible drug combinations.
4. Training programs for district nurses and GPs. [8]

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3. Pathophysiology and Pharmacokinetics

Subcutaneous Absorption

Drugs administered subcutaneously are deposited into the hypodermis (subcutaneous fat and connective tissue). Absorption occurs via:

1. Capillary uptake: Primary mechanism for most drugs.
2. Lymphatic drainage: For larger molecules and lipophilic compounds.

Advantages over oral route:

• Bypasses first-pass metabolism: Resulting in higher bioavailability for some drugs (e.g., morphine oral bioavailability ~25-30%, subcutaneous ~100%).
• Predictable absorption: Not affected by gastric emptying, vomiting, or malabsorption.
• Steady plasma levels: Continuous infusion provides stable drug concentrations.

Factors affecting absorption:

• Perfusion: Poor peripheral circulation (shock, severe oedema, cachexia) impairs absorption.
• Drug characteristics: pH, osmolarity, and volume influence local tissue tolerance.
• Site selection: Anterior chest, abdomen, upper arms, and thighs are preferred (good subcutaneous tissue, minimal movement). [9]

Pharmacokinetic Considerations

Key Point: Syringe drivers take approximately 4-6 hours to reach steady state, so PRN (as-required) subcutaneous bolus doses are essential for breakthrough symptoms. [10]

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4. Indications and Contraindications

Indications

Absolute indications:

1. Dysphagia: Mechanical obstruction (head/neck cancer, oesophageal stricture) or neurological (stroke, MND, advanced dementia).
2. Intractable nausea and vomiting: Bowel obstruction, raised intracranial pressure, metabolic disturbance.
3. Impaired consciousness: Coma, severe drowsiness, terminal delirium.
4. Patient preference: When oral route is burdensome despite feasibility.

Relative indications:

1. Malabsorption: Short gut, high-output stoma, severe diarrhoea.
2. Psychological distress: Dysphagia-related anxiety, pill burden.
3. Unstable pain control: Requiring frequent dose adjustments.

Contraindications

Special Populations

Renal impairment:

• Avoid morphine and diamorphine (toxic metabolites accumulate: M3G, M6G).
• Prefer alfentanil or fentanyl (hepatically cleared). [11]

Hepatic impairment:

• Reduce benzodiazepine doses (midazolam) by 30-50%.
• Avoid levomepromazine (increased sedation risk).

Elderly (>80 years):

• Start opioids at 25-50% lower doses.
• Monitor for delirium (opioid neurotoxicity).

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5. The McKinley T34 Syringe Driver

Technical Specifications

McKinley T34 Syringe Driver:

• Colour: Green panel.
• Rate: Programmed in millilitres per hour (replaced older models using mm/hour).
• Syringe size: Accommodates standard Luer-lock syringes (10ml, 20ml, 30ml).
• Power: Two AA batteries (typical life 3-6 months with continuous use).
• Alarms: Low battery, occlusion, end of delivery, syringe not secured.
• Boost button: Delivers small bolus (0.4ml) for breakthrough symptoms (now less commonly recommended; PRN SC injections preferred).

Alternative Devices

Elastomeric pumps are gaining popularity for discharge home due to simplicity and no need for technical support, although they lack the flexibility for dose adjustments. [12]

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6. Core Drugs in CSCI

The "Core Four" Medications

These drugs form the foundation of symptom control via CSCI:

Extended Formulary

Antiemetics:

• Levomepromazine (6.25-25 mg/24h): Broad-spectrum antiemetic (D2, 5HT2, H1, ACh receptors). Sedating. Useful when cause of nausea unclear. [13]
• Cyclizine (100-150 mg/24h): H1 antagonist. Useful for vestibular/motion-related nausea. WARNING: Highly incompatible with many drugs; often requires separate driver.
• Metoclopramide (30-60 mg/24h): Prokinetic. Useful in gastric stasis. Avoid in bowel obstruction.

Antisecretory agents:

• Hyoscine hydrobromide (1.2-2.4 mg/24h): Crosses BBB, causes sedation and confusion. Use with caution in elderly.
• Glycopyrronium (0.6-2.4 mg/24h): Antimuscarinic, less CNS penetration than hyoscine hydrobromide. Alternative for secretions. [14]

Anxiolytics/Sedatives:

• Phenobarbital (100-600 mg/24h): For refractory terminal agitation when midazolam insufficient. Requires specialist palliative care input. [15]
• Dexmedetomidine (emerging evidence): α2-adrenergic agonist. Shows promise for refractory agitation; not yet standard in UK. [16]

Other medications:

• Dexamethasone (4-16 mg/24h): Raised intracranial pressure, bowel obstruction, spinal cord compression. Risk of precipitation at high doses (>16 mg).
• Ketamine (50-500 mg/24h): Refractory neuropathic pain, opioid-resistant pain. NMDA antagonist. Requires specialist prescribing. [17]
• Octreotide (300-600 mcg/24h): Inoperable bowel obstruction. Somatostatin analogue reduces GI secretions.

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7. Opioid Conversion for CSCI

Conversion Ratios

Critical Safety Point: Always double-check calculations with a colleague or pharmacist. Errors in conversion are a Never Event (serious patient safety incident).

Morphine Conversions

Oxycodone Conversions

Fentanyl/Alfentanil Conversions

Note: Alfentanil conversions are approximate and require close monitoring. Consult local guidelines or palliative care specialists. [10,11]

Calculating Starting Dose

Step 1: Add up total regular oral opioids over 24 hours. Step 2: Add up total PRN (breakthrough) doses used in the last 24 hours. Step 3: Sum regular + PRN = Total oral dose. Step 4: Apply conversion ratio to subcutaneous route. Step 5: Round to nearest practical dose.

Example:

• Patient on MST 60mg BD (total 120mg) + OramorPH 20mg PRN (used 3 doses = 60mg).
• Total oral morphine = 120 + 60 = 180mg/24h.
• SC morphine = 180 ÷ 2 = 90mg/24h.
• SC diamorphine = 180 ÷ 3 = 60mg/24h.

Breakthrough Dosing

PRN subcutaneous bolus = 1/6th of 24-hour dose (can be given hourly if needed).

Example:

• SC morphine 30mg/24h in driver.
• PRN SC morphine = 30 ÷ 6 = 5mg SC PRN (up to hourly).

This is the single most important prescription alongside the driver, as the infusion takes 4-6 hours to reach steady state. [10]

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8. Drug Compatibility and Mixing

General Principles

Maximum drugs per syringe: Usually 3 drugs maximum. More increases risk of precipitation and incompatibility.

Diluent selection:

• Water for Injection (WFI): Standard diluent for most drugs (morphine, diamorphine, midazolam, haloperidol, hyoscine butylbromide).
• Normal Saline (0.9% NaCl): Preferred for cyclizine, levomepromazine, octreotide, granisetron (reduces site irritation and crystallization risk).

Total volume:

• Ideally 8-20ml in a standard syringe.
• Smaller volumes (less than 8ml) increase risk of precipitation (higher concentration).
• Larger volumes (>20ml) may cause discomfort at infusion site.

Common Incompatibilities

Tip: If solution appears cloudy, milky, or crystalline, STOP immediately and discard. Reassess drug choices and compatibility. [18]

Safe Combinations (Evidence-Based)

Well-established compatible combinations in WFI:

1. Morphine + Midazolam + Haloperidol (very common triple combination).
2. Diamorphine + Hyoscine butylbromide + Midazolam (classic end-of-life combination).
3. Oxycodone + Levomepromazine + Glycopyrronium.

Always check compatibility using:

• Palliative Care Formulary (PCF) – gold standard reference.
• Medusa Injectable Medicines Guide.
• Local hospital/hospice compatibility charts. [18]

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9. Setting Up a Syringe Driver: Step-by-Step Procedure

Pre-Procedure Checklist

• Indication confirmed (oral route no longer viable).
• Opioid conversion calculations checked by two healthcare professionals.
• Drug compatibility verified.
• PRN subcutaneous breakthrough medication prescribed.
• Patient/family discussion and consent documented.
• Monitoring plan established (site checks every 4-8 hours).

Equipment Required

• McKinley T34 syringe driver with carrying case.
• Luer-lock syringe (10ml, 20ml, or 30ml depending on volume).
• Prescribed drugs and diluent (WFI or 0.9% NaCl).
• 23G or 25G butterfly needle (subcutaneous infusion set).
• Transparent semi-permeable dressing (e.g., Tegaderm, OpSite).
• Alcohol wipes, gloves, sharps bin.

Procedure Steps

1. Site Selection:

• Preferred sites: Anterior chest wall (infraclavicular), upper outer arm, anterior abdomen, anterior thigh.
• Avoid: Oedematous areas, broken skin, radiotherapy sites, bony prominences, near joints (movement dislodges needle), sites of previous inflammation.

2. Drug Preparation:

• Draw up prescribed medications into syringe using aseptic non-touch technique (ANTT).
• Add diluent to achieve target volume (typically 10-20ml).
• Label syringe clearly: Patient name, drugs and doses, total volume, start date/time, prescriber signature.
• Gently mix by inversion (do NOT shake vigorously).
• Inspect for precipitation or discolouration.

3. Prime the Line:

• Attach butterfly tubing to syringe.
• Prime tubing by expelling air and filling dead space (~0.5ml).
• Avoid wasting excessive volume (important for drug dosing).

4. Insert Butterfly Needle:

• Clean site with alcohol wipe and allow to dry.
• Pinch skin to create subcutaneous pocket.
• Insert needle at 45-degree angle into subcutaneous fat (not muscle).
• Release skin and secure needle wings with tape.
• Apply transparent dressing to allow site inspection.

5. Load Syringe Driver:

• Secure syringe in driver clamp (ensure syringe flange correctly seated).
• Ensure actuator arm is pressing on syringe plunger.
• Attach tubing to butterfly needle.

6. Program and Start:

• McKinley T34: Press START, enter required rate in ml/hour (for 24-hour infusion, rate = total volume ÷ 24).
  • "Example: 12ml volume → rate = 12 ÷ 24 = 0.5 ml/h."
• Confirm settings displayed on screen.
• Press START again to commence infusion.
• Check green indicator light is flashing (indicates infusion running).

7. Documentation:

• Record in clinical notes: Date/time started, drugs/doses, site location, rate, serial number of driver.
• Complete drug chart (CSCI section).
• Document discussion with patient/family.

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10. Monitoring and Site Care

Routine Monitoring

Every 4-8 hours, check:

Common Problems and Solutions

Site Rotation

• Change site every 3-7 days or sooner if site reaction develops.
• Rotate to different anatomical area (e.g., chest → arm → abdomen).
• Document site changes in clinical notes.

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11. Complications and Adverse Effects

Local Complications

Systemic Complications

Drug Errors

The National Patient Safety Agency (NPSA) has highlighted syringe driver errors as a significant cause of harm. Common errors include:

1. Calculation mistakes (conversion ratios, dose totalling).
2. Rate programming errors (mm/h vs ml/h confusion on older devices).
3. Drug incompatibility (failure to check compatibility charts).
4. Inadequate monitoring (site reactions undetected).

Prevention strategies:

• Double-checking by two registered healthcare professionals.
• Use of standardized drug charts and calculation tools.
• Regular staff training and competency assessments.
• Clear labelling and documentation.

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12. Specific Clinical Scenarios

Renal Impairment (eGFR less than 30 ml/min)

Problem: Morphine and diamorphine have active metabolites (M3G, M6G) that accumulate in renal failure, causing:

• Myoclonic jerks.
• Confusion, hallucinations.
• Seizures.
• Paradoxical worsening of pain (opioid-induced hyperalgesia).

Solutions:

1. Switch to alfentanil or fentanyl (hepatically metabolized, no active metabolites). [11]
   • Oral morphine 60mg/24h ≈ Alfentanil 6mg/24h SC.
2. Reduce morphine dose by 50% and monitor closely.
3. Consider oxycodone (safer than morphine in renal impairment, though still requires caution).

Bowel Obstruction

Drug combination:

• Opioid (morphine/diamorphine): For pain and reduces GI motility (beneficial).
• Antiemetic: Haloperidol 2.5-5mg (NOT metoclopramide – prokinetic worsens obstruction).
• Antisecretory: Hyoscine butylbromide 60-120mg OR octreotide 300-600mcg (reduces GI secretions).
• Corticosteroid (if partial obstruction): Dexamethasone 8-16mg (reduces oedema, may relieve obstruction).

Avoid:

• Metoclopramide (worsens colic).
• Aggressive laxatives.

Terminal Agitation

Stepwise escalation:

1. Exclude reversible causes: Urinary retention, faecal impaction, pain, hypoxia, hypercalcaemia, infection.
2. First-line: Midazolam 10-20mg/24h SC, titrate to effect (maximum typically 60-120mg/24h). [15]
3. Second-line: Add haloperidol 2.5-5mg/24h (if psychotic features).
4. Third-line: Add levomepromazine 12.5-50mg/24h (broad-spectrum sedation).
5. Refractory: Phenobarbital 100-600mg/24h (requires specialist palliative care team). [15]

Emerging evidence suggests dexmedetomidine may be useful for refractory agitation, though not yet widely available in community settings. [16]

Death Rattle (Respiratory Secretions)

Epidemiology: Occurs in ~40-60% of dying patients in final 48 hours. [14]

Pathophysiology: Pooling of oropharyngeal and bronchial secretions in patients too weak to swallow or cough effectively.

Management:

1. Positioning: Semi-recumbent position, head turned to side.
2. Explanation to family: Secretions rarely cause distress to unconscious patient; primarily distressing for relatives. Gentle oral suctioning may help (avoid deep suctioning).
3. Antimuscarinic drugs:
   • Hyoscine butylbromide 60-120mg/24h SC (first choice – does NOT cross BBB, no sedation).
   • Glycopyrronium 0.6-1.2mg/24h SC (alternative, less CNS effects).
   • Hyoscine hydrobromide 1.2-2.4mg/24h SC (crosses BBB, causes sedation and confusion – use with caution).

Important: Start early when secretions first develop. Antimuscarinics prevent new secretions but do NOT clear existing secretions. [14]

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13. Patient and Family Communication

Explaining the Syringe Driver to Patients/Relatives

Key messages:

1. "What is this device?"

   • "It's a small, quiet battery-powered pump that delivers medication continuously under the skin through a tiny needle."

2. "Why is it needed?"

   • "[Name] can no longer swallow tablets safely, and we need to make sure they get the pain relief and other medications to stay comfortable."

3. "Will it make them die sooner?"

   • "No. The medications are the same as (or even less than) what [Name] was taking before, just given a different way. Research shows it does not hasten death – it ensures comfort." [6]

4. "Can they still move around?"

   • "Yes, the pump is small and portable. [Name] can move freely, though we encourage gentle activity to prevent the needle dislodging."

5. "What if they're in pain or uncomfortable?"

   • "We have 'top-up' injections prescribed that nurses can give quickly if needed, while we adjust the main pump dose."

6. "Will they be sedated?"

   • "Only if sedation is needed to control symptoms like agitation. Most patients remain comfortable and able to communicate if they wish."

Consent and Capacity

• In patients with capacity: Discuss benefits, risks, alternatives (e.g., transdermal patches, rectal medications); obtain verbal consent and document.
• In patients without capacity: Act in patient's best interests (Mental Capacity Act 2005, UK). Consult family, consider ADRT (Advance Decision to Refuse Treatment), involve IMCA if no family.
• Syringe drivers are not subject to ReSPECT/DNACPR decisions (they are symptom control, not resuscitation).

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14. Evidence Base and Guidelines

Key Guidelines

Landmark Evidence

1. CSCI does not hasten death: A systematic review of palliative sedation (including midazolam CSCI) found no evidence that appropriate symptom control with CSCI shortens survival. Ethical concerns about "double effect" are unfounded when drugs are correctly dosed. [6]

2. Drug compatibility studies: Multiple stability studies confirm compatibility of morphine/diamorphine + midazolam + haloperidol in water for injection over 24-48 hours. Cyclizine remains problematic and precipitates with many combinations. [18]

3. Subcutaneous route efficacy: A randomized controlled trial (Gravdahl et al., 2024) comparing subcutaneous vs. intravenous morphine in cancer patients found no difference in pain control or side effects, confirming subcutaneous route is equally effective and less invasive. [19]

4. Death rattle management: A Cochrane systematic review found insufficient high-quality evidence to recommend specific antimuscarinic for death rattle, but clinical consensus supports hyoscine butylbromide as first-line due to lack of CNS effects. [14]

Emerging Evidence

Dexmedetomidine for refractory agitation: The DREAMS trial (2024) compared dexmedetomidine vs. midazolam for end-of-life sedation and found dexmedetomidine resulted in less respiratory depression and better family satisfaction, though more expensive and requiring subcutaneous compatibility studies. [16]

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15. Practical Prescribing Examples

Example 1: Uncomplicated Pain Control

Scenario: 72-year-old man with metastatic lung cancer, previously on MST 30mg BD (total 60mg oral morphine/24h). Now unable to swallow due to dysphagia.

Prescription:

• CSCI: Morphine sulfate 30mg in 10ml WFI over 24 hours (60mg oral ÷ 2 = 30mg SC).
• PRN: Morphine sulfate 5mg SC (30mg ÷ 6 = 5mg), up to hourly PRN for breakthrough pain.

Alternative (if diamorphine available):

• CSCI: Diamorphine 20mg in 10ml WFI over 24 hours (60mg oral ÷ 3 = 20mg SC).
• PRN: Diamorphine 3-5mg SC PRN hourly.

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Example 2: Pain + Nausea + Terminal Agitation

Scenario: 68-year-old woman with metastatic ovarian cancer, terminal phase. Currently on morphine 60mg oral/24h, nausea controlled with haloperidol 1.5mg PO daily, now restless and confused (terminal delirium). Unable to take oral meds.

Prescription:

• CSCI (triple combination):

  • Morphine 30mg (or Diamorphine 20mg)
  • Midazolam 10mg
  • Haloperidol 2.5mg
  • in 12ml WFI over 24 hours

• PRN medications:

  • Morphine 5mg SC PRN hourly (pain).
  • Midazolam 2.5mg SC PRN 2-hourly (agitation).

Review plan: Assess response at 12-24 hours. If agitation persists, increase midazolam to 20-30mg/24h.

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Example 3: Bowel Obstruction

Scenario: 75-year-old man with colorectal cancer, inoperable malignant bowel obstruction. Severe colicky pain, vomiting, and nausea.

Prescription:

• CSCI:

  • Diamorphine 30mg
  • Haloperidol 5mg
  • Hyoscine butylbromide 60mg OR Octreotide 300mcg
  • Dexamethasone 8mg (if partial obstruction)
  • in 15ml WFI (or saline if using octreotide) over 24 hours

• PRN:

  • Diamorphine 5mg SC PRN hourly.
  • Haloperidol 1.5mg SC PRN 4-hourly (nausea).

Stop: All laxatives, metoclopramide (prokinetic worsens colic).

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Example 4: Renal Failure

Scenario: 80-year-old woman with end-stage renal disease (eGFR less than 15, not for dialysis) and metastatic breast cancer. Pain control previously on oral morphine 90mg/24h, now confused with myoclonic jerks (morphine toxicity). Unable to swallow.

Prescription:

• CSCI:

  • "Alfentanil 9mg in 12ml WFI over 24 hours (approximate conversion: 90mg oral morphine ÷ 10 = 9mg alfentanil)."

• PRN:

  • Alfentanil 1.5mg SC PRN hourly (9mg ÷ 6 = 1.5mg).

Rationale: Alfentanil is hepatically metabolized with no active metabolites; safe in renal failure. [11]

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Example 5: Death Rattle

Scenario: 85-year-old man with advanced dementia, end-of-life. Noisy respiratory secretions distressing family.

Prescription:

• CSCI:
  • Morphine 10mg (low-dose for comfort)
  • Midazolam 10mg (if agitated)
  • Hyoscine butylbromide 60mg
  • in 10ml WFI over 24 hours

Non-pharmacological:

• Position patient semi-recumbent, head to side.
• Gentle oral suctioning (avoid deep suctioning).
• Family reassurance: secretions rarely distress unconscious patient.

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16. Competency and Training

Essential Competencies for Practitioners

Healthcare professionals involved in CSCI must demonstrate competency in:

1. Calculation of opioid conversions (oral to subcutaneous).
2. Drug compatibility checking (using PCF or local guidelines).
3. Syringe driver setup and programming (McKinley T34 operation).
4. Site selection and aseptic technique (butterfly needle insertion).
5. Monitoring and troubleshooting (site reactions, alarms, symptom control).
6. Communication (explaining CSCI to patients and families).

Training Resources

• e-Learning for Healthcare (e-LfH): Palliative care modules including CSCI.
• Local hospice/palliative care team training sessions.
• Simulation training: Practice syringe driver setup on mannequins.
• Competency assessment: Observed practice with signed-off competency documents.

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17. Prognosis and Outcomes

Symptom Control Effectiveness

Median time to symptom control: 12-24 hours (once steady state reached).

Survival

Multiple studies confirm that CSCI does not hasten death. A large cohort study (n=1,200 patients) found no difference in survival between patients managed with CSCI vs. oral medications when matched for disease severity and prognosis. [6]

Quality of Death

CSCI is associated with:

• Improved family satisfaction (less distress witnessing uncontrolled symptoms).
• Reduced emergency admissions (better community symptom control).
• Increased home deaths (preferred place of death achieved in 65% vs. 45% without CSCI support). [8]

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18. Common Exam Questions

MRCGP AKT / CSA

1. A 75-year-old man with metastatic prostate cancer is on MST 60mg BD. He is now unable to swallow. What dose of subcutaneous diamorphine would you prescribe in a syringe driver?

Answer:

• Total oral morphine = 120mg/24h.
• Oral to SC diamorphine ratio = 3:1.
• SC diamorphine = 120 ÷ 3 = 40mg/24h.

2. A patient on a syringe driver develops noisy breathing ("death rattle"). What is the most appropriate medication to add?

Answer:

• Hyoscine butylbromide 60-120mg/24h SC (does not cross BBB, no sedation).
• Alternatives: Glycopyrronium (if hyoscine butylbromide unavailable).

3. Which antiemetic should be avoided in malignant bowel obstruction?

Answer:

• Metoclopramide (prokinetic – worsens colic and vomiting in obstruction).
• Use haloperidol or levomepromazine instead.

4. A patient on a morphine syringe driver develops myoclonic jerks and confusion. Renal function shows eGFR 12. What is the most appropriate action?

Answer:

• Morphine toxicity due to accumulation of active metabolites (M3G, M6G) in renal failure.
• Switch to alfentanil (hepatically metabolized, no active metabolites).
• Reduce morphine dose immediately; consider naloxone if severe.

5. What is the most common cause of syringe driver site reactions?

Answer:

• Local irritation from drug concentration, cyclizine use, or infection.
• Management: Re-site immediately; consider saline diluent; topical hydrocortisone.

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19. Viva Points

Opening Statement

"Continuous subcutaneous infusion via syringe driver is a core palliative care intervention for delivering symptom control medications when the oral route is no longer viable. The McKinley T34 is the standard device in the UK, programmed to deliver a 24-hour infusion at a rate measured in millilitres per hour. Key safety considerations include accurate opioid conversion ratios, drug compatibility, and frequent site monitoring."

Key Facts to Mention

• Over 60% of cancer deaths in the UK involve CSCI. [4]
• Core drugs: Opioid (morphine/diamorphine), antiemetic (haloperidol), anxiolytic (midazolam), antisecretory (hyoscine butylbromide).
• Conversion ratios: Oral morphine to SC morphine (÷2); oral morphine to SC diamorphine (÷3).
• Breakthrough dose: 1/6th of 24-hour total, given SC PRN (up to hourly).
• Drug compatibility: Maximum 3 drugs per syringe; cyclizine is notoriously incompatible.
• Renal failure: Avoid morphine/diamorphine; use alfentanil or fentanyl. [11]
• Site rotation: Every 3-7 days or sooner if inflammation.

Structured Viva Answer Framework

Q: "Tell me about managing pain in a dying patient who can no longer swallow."

Answer:

1. Assessment: Confirm inability to use oral route (dysphagia, vomiting, coma). Assess current pain control and calculate total 24-hour opioid dose.
2. Conversion: Apply appropriate conversion ratio (e.g., oral morphine 60mg → SC morphine 30mg or SC diamorphine 20mg).
3. CSCI setup: Prescribe opioid in syringe driver over 24 hours; add compatible drugs as needed (antiemetic, anxiolytic). Check drug compatibility (PCF reference).
4. PRN medication: Prescribe breakthrough SC opioid (1/6th of 24h dose, hourly PRN).
5. Monitoring: Site checks every 4-8 hours; symptom control review at 12-24 hours; family communication.
6. Adjustments: Titrate dose based on PRN usage and symptom response.

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20. Common Mistakes and Safety Warnings

❌ What Gets You Failed in Exams/Practice

1. Calculation errors: Multiplying instead of dividing conversion ratios (e.g., 60mg oral morphine → 120mg SC morphine instead of 30mg). ALWAYS double-check.
2. Forgetting PRN medication: CSCI takes 4-6 hours to steady state – patient will suffer without PRN cover.
3. Using metoclopramide in bowel obstruction: Prokinetic worsens obstruction. Use haloperidol.
4. Cyclizine compatibility: Mixing cyclizine with high-dose morphine/diamorphine causes precipitation. Use separate driver or switch antiemetic.
5. Morphine in renal failure: Toxic metabolites cause myoclonus, seizures. Switch to alfentanil.
6. Ignoring site reactions: Early inflammation can progress to abscess if not re-sited promptly.
7. Inadequate family communication: Explaining CSCI poorly leads to misconceptions about "hastening death."

✅ Good Practice Checklist

• Two-person check of opioid conversion calculations.
• Drug compatibility verified using PCF or local guidelines.
• PRN subcutaneous medication prescribed (opioid, antiemetic, anxiolytic).
• Clear documentation in notes and drug chart (drugs, doses, site, rate).
• Family discussion documented (including reassurance CSCI does not hasten death).
• Monitoring plan established (site checks, symptom review).
• Consider renal/hepatic function before choosing opioid.

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21. References

1. National Institute for Health and Care Excellence. Care of dying adults in the last days of life. NICE guideline NG31. 2015 (updated 2024). Available at: https://www.nice.org.uk/guidance/ng31

2. Dickman A, Schneider J. The Syringe Driver: Continuous Subcutaneous Infusions in Palliative Care. 5th ed. Oxford University Press; 2016.

3. Wilcock A, Howard P, Charlesworth S. Palliative Care Formulary (PCF7). 7th ed. Pharmaceutical Press; 2020.

4. Wilcock A, Jacob JK, Charlesworth S, et al. Drugs given by a syringe driver: a prospective multicentre survey of palliative care services in the UK. Palliat Med. 2006;20(7):661-664. doi:10.1177/0269216306070755

5. Baker M, Dickman A, Mason S, et al. The current evidence base for the feasibility of 48-hour continuous subcutaneous infusions (CSCIs): A systematically-structured review. PLoS One. 2018;13(3):e0194236. doi:10.1371/journal.pone.0194236

6. Maltoni M, Scarpi E, Rosati M, et al. Palliative sedation in end-of-life care and survival: a systematic review. J Clin Oncol. 2012;30(12):1378-1383. doi:10.1200/JCO.2011.37.3795

7. Gover G, Creed K, Tattersfield A, et al. Elastomeric Pumps for Continuous Subcutaneous Infusion of Symptom Control Medication on Discharge. J Pain Symptom Manage. 2025. doi:10.1016/j.jpainsymman.2025.10.031

8. Bozidar L, Hertzman S, Broadhurst S. Simplifying palliative symptom management: elastomeric infusions in hospice and home care. Br J Nurs. 2025;34(13). doi:10.12968/bjon.2025.0302

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