The use of intrathecal opioids should be restricted to <=25mcg fentanyl.

 

Rationale

Opioid co-administration prolongs postoperative analgesia with equipotent doses of intrathecal local anaesthetic (8 hours morphine, 2 hours fentanyl) [1].

Opioid co-administration allows lower doses of intrathecal local anaesthetic to be used, but in this combination does not prolong postoperative analgesia compared to standard dose of intrathecal local anaesthetic alone [2].

BUT

  • there is no evidence for these in hip fracture
  • diamorphine is preferred by most anaesthetists in the UK [3], but there is no evidence for what dose of diamorphine provides the optimal risk/benefit ratio in hip fracture patients.
  • intrathecal (dia)morphine is associated with more side-effects than fentanyl, including itching, respiratory depression, urinary retention and nausea and vomiting [1]
  • anecdotally, intrathecal opioids increase somnolence and confusion in hip fracture patients, but this has not been confirmed by research
  • postoperatively, the painful hip fracture is fixed
  • postoperative analgesia is provided by pre-spinal nerve block
  • minimal effective doses of intrathecal morphine and fentanyl should be used [1].

 

Urgent work needs to be done comparing the effect/side-effect profile of low-dose 0.5% bupivacaine + opioid vs. low-dose 0.5% bupivacaine + nerve block in hip fracture patients.

Evidence

1. Pöpping DM, Elia N, Marret E, Wenk M, Tramèr MR. Opioids added to local anesthetics for single-shot intrathecal anesthesia in patients undergoing minor surgery: a meta-analysis of randomized trials. Pain 2012; 153: 784-93.

2. Pöpping DM, Elia N, Wenk M, Tramèr MR. Combination of a reduced dose of an intrathecal local anesthetic with a small dose of an opioid: a meta-analysis of randomized trials. Pain 2013; 154: 1383-90.

3. White SM, Moppett IK, Griffiths R et al. Outcomes after anaesthesia for hip fracture surgery. Secondary analysis of prospective observational data from 11 085 patients included in the UK Anaesthesia Sprint Audit of Practice (ASAP 2). Anaesthesia 2016; 71: 506-14.