Pain and regional anaesthesia · Core07 / 13

Buprenorphine maintenance for spinal fusion34-year-old man, 82 kg, for elective L3–S1 posterior spinal fusion

Opioid-tolerant patient: buprenorphine continuation, multimodal analgesia and opioid overdose

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Know this first

Buprenorphine: partial mu agonist, high affinity, slow dissociation; it displaces other opioids.
Most protocols continue buprenorphine; stopping risks relapse, overdose and withdrawal.
Expect higher short-acting opioid needs; add multimodal and regional analgesia.
Buprenorphine respiratory depression may need a naloxone infusion.

The patient

34-year-old man, 82 kg, for elective L3–S1 posterior spinal fusion. Opioid use disorder, stable for 3 years on sublingual buprenorphine-naloxone 16 mg daily; anxiety; untreated hepatitis C. Drugs: buprenorphine-naloxone, sertraline. Vitals: BP 128/80, HR 76, SpO2 98% on air, RR 14; ALT 64 U/L, platelets 210 × 10⁹/L.

The examiner asks

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Consider
What are your considerations?
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- A 34-year-old on buprenorphine for opioid use disorder, for major elective spinal fusion. Patient
- Buprenorphine binds tightly and leaves slowly, so other opioids work less well in him. Disease
- His hepatitis C means standard precautions; a needlestick is the main risk to staff.
Prepare
Do you stop his buprenorphine?
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- No. Stopping risks relapse, overdose and withdrawal, and most protocols continue it. Disease
- I plan with his prescriber; some protocols taper to 12–16 mg a day, where he already is.
- I tell him he'll need more opioid than most, and that we will treat his pain. Patient
- Plain, non-judgemental language, and his discharge opioid plan agreed before surgery. After surgery
Plan
What is your analgesic plan?
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- His usual buprenorphine dose continues on the morning of surgery and afterwards. Disease
- Ketamine 0.5 mg/kg at induction, then an infusion through surgery.
- Paracetamol 1 g IV every 6 hours; a lidocaine infusion is an option.
- Regional or intrathecal analgesia with the surgeon's agreement, wherever possible. Surgery
- PCA with a short-acting opioid and no background infusion. Disease
- Continuous oximetry and sedation checks on the ward. After surgery
Crisis
In recovery he is distressed, pain 10/10 after 20 mg of morphine IV. BP 160/95, HR 112, RR 18, SpO2 97%. What do you do?
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- Severe pain on buprenorphine is expected; I treat it rather than label him drug-seeking. Crisis
- I check his leg power and sensation for a new deficit after the fusion. Surgery
- A ketamine bolus, roughly 0.25 mg/kg IV, then a higher infusion rate. Crisis
- More short-acting opioid in titrated boluses while RR and sedation stay safe.
- Wound infiltration or a catheter if the surgeon agrees.
Crisis
At 04:00 on the ward he is hard to rouse, RR 7, SpO2 86% on air, with morphine PCA running. What do you do?
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- Opioid respiratory depression: stop the PCA, rouse him, open the airway, oxygen; call for help. Crisis
- Naloxone 40 mcg IV every 2 minutes, escalating if he doesn't respond; buprenorphine may need more.
- With buprenorphine on board, boluses may not last; he may need a naloxone infusion.
- Naloxone lasts 15–45 minutes, so I watch closely for re-sedation.
- HDU overnight; I review his PCA settings and any other sedatives. After surgery

Fatal mistakes

Stopping his buprenorphine before surgery.
Withholding opioids because he is seen as drug-seeking.
A background PCA infusion without monitoring.
Single naloxone bolus and no observation afterwards.

Checked against: Stoelting 8e · Barash 9e · Miller 10e

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