STH Consultant CPD Updates: Pain

This is the summary of the PowerPoint presentations from this month’s  consultant CPD teaching programme.

This month’s session provided an update on pain management in line with the Royal College of Anaesthetists Matrix.

The following areas were covered by Dr Nick Plunkett, Dr Rob Atcheson and Dr Ravi Parekodi (all Consultant Anaesthetists, Sheffield Teaching Hospitals NHS Foundation Trust). Please click the link for a copy of the presentation.

Advertisements

ABRA ASM Nottingham 2013: Key Points

Dr Steve Rowe (@Kangaroosteve) recently attended the Association of Burns & Reconstructive Anaesthetists ASM (November 2013) held in N0ttingham, and has very kindly provided us with his reflections on the talks.

The RCOA Matrix Codes for each talk are shown (in my opinion, the organisers didn’t provide them), along with the details of the speaker.

Association of Burns and Reconstructive Anaesthetists Nottingham 15th November 2013

Long Term Outcomes in Chronic Pain – do perioperative techniques alter outcome? (2E03): Dr Simon Tordoff, Leicester.

  • Chronic pain after surgery is common, but not often consented for
  • Hernia repair @ 1 Year – 19% some pain; 6% moderate or severe pain; 6% Severe pain restricting daily function (Callesen Br J Surg 1999)
  • These outcomes are verified by a very large Swedish study looking at their hernia registry (like our joint registry).
  • Knee replacements – 20% unsatisfied at 1 year due to pain (and pain commonest indication to perform surgery in first place….)
  •  Thoracotomy –   61% pain after 1 year, 3-5% severe pain; Neuropathic pain 21% at 7 years
  •  Amputation – 50-75% Phantom limb pain; 20-50% Stump pain
  • Given the above, the suggestion was that it may be prudent to screen for psychological vulnerability to develop chronic pain.

Significant risk factors are:

  1. Poor post operative pain control
  2. Pre-existing chronic pain
  3. Surgical complication
  4. Multiple surgeries
  5. Obesity and disordered glucose metabolism – sensitizes to post op pain.

Take home message – a conservative estimate of 2-4% severe chronic pain after surgery – probably should be consented for specifically, and a big national audit would be nice.

Opioid rotations and other strategies (2E01): Dr Doug Johnson, Birmingham.

S/E of opioids well known – constipation, N+V, Itch, tolerance

Opioid induced hyperalgesia (OIH) is recognised more, especially in burns patients.

OIH gives increased pain with increased doses of opioids, with a change in the pain charateristics – more diffuse, allodynia, aslong with neuro-excitation phenomena (this is something we are most familiar with – “post-remifentanil” patients in recovery).

Thought to be NMDA/Glutamate mediated.

Recognition is important. First line therapy is to increase the dose of opioid and evaluate for increased efficacy – this would be indicative of tolerance rather than OIH. If pain and other symptoms worsen, OIH likely.

Management

  1. Decrease or eliminate opioid
  2. Switch or rotate opioids
  3. Utilise other agents with NMDA receptor activity – ketamine/gapapentoid
  4. Utilise combination therapies – paracetamol/Nsaids etc etc

Opioid rotation

  • There is incomplete cross tolerance, with different drugs having a range of effects on other receptor systems e.g. Methadone and NMDA receptors
  • The switch is thought to allow the body to get rid of morphine-3-glucuronide, a metabolic product with no significant opioid receptor activity, but implicated in tolerance and other side effects.
  • Switching morphine to fentanyl often fails dues to rapid tolerance developing to fentanyl.
  • Methadone theoretically a good option.
  • Oxycodone also a viable alternative.

Ketamine

Cochrane review in 2010 supports is use in acute post op pain

http://summaries.cochrane.org/CD004603/perioperative-ketamine-for-acute-postoperative-pain

Ketamine in subanaesthetic dose (that is a dose which is below that required to produce anaesthesia) is effective in reducing morphine requirements in the first 24 hours after surgery. Ketamine also reduces postoperative nausea and vomiting. Adverse effects are mild or absent.”

Benefits shown with:

  1. Pre-incision bolus/Bolus at wound closure/continuous peri-operative infusion/post-op infusion with morphine.
  2. No benefit demonstrated with >30mg TOTAL in 24 hours
  3. Doses discussed for bolus treatment peri-operatively were in the range 75-100mcg/kg, though it seems that p to 0.5mg/kg can be used without a rise in side effects.

Gabapentin

  • Indirectly inhibits NMDA receptor overactivity
  • Only convincing evidence is that it decreases “Burns itch” – 300-1200mg tds po

Pregabalin

  • BD dosing, Lower doses, NICE approved
  • More expensive
  • >5% body surface area burns – gives a significant reduction in pain/itch and procedural pain
  • No difference in LOS or opioid consumption
  • No difference in pain at 6 months

Other talks were related to foreign forays providing anaesthesia for reconstructive surgery

The first was for reconstructive surgery after noma (cancrum oris) a disease of poverty in sub-Saharan Africa – the main thrust of the talk was that these patients have difficult airways, often with absolute trismus, but with very careful planning airway disasters were avoided. This involved a 2-consultant airway assessment and documentation of airway plan.

The second was a trainee presentation that won the Russell Davis and Stuart Laird Prize  – the trainee discussed providing regional anaesthesia in a resource poor environment.

The final discussion related to revalidation and appraisal. Whilst useful, it generated no significant take home points.

It is likely that the meeting next year will be held in Manchester, and Sheffield in 2015.