A commonly heard claim is that propofol has no analgesic effect. Nevertheless did we use propofol as the only agent for sedation during manipulation with orthopaedic patients at one anaesthetic department I worked at. With great effect. We were happy, patients were happy. Many other anaesthetists I’ve talked to have been very sceptical.
I never researched the phenomenon before, but when doing a PubMed search, I get quite a few hits for studies looking at propofol for sedation for painful procedures. And many of them with only propofol. No opioids.
Here’s one such study:
Background: The use of procedural sedation and analgesia to allow painful orthopaedic manipulations in the emergency department has become a standard practice over the last decade. Both propofol and midazolam/ketamine are attractive sedative regimens for routine use in the emergency department. We hypothesized that sedation with propofol as compared with midazolam/ketamine will save time in the emergency department. The purpose of the present study was to compare the recovery time, the total sedation time, and the adverse events of procedural sedation and analgesia induced with propofol as compared with midazolam/ketamine.
Methods: This prospective randomized study was conducted in the emergency department of a tertiary care, university-affiliated medical center. All sedations and orthopaedic manipulations were performed by trained and approved orthopaedic residents assisted by a registered nurse according to the same protocol. Sedation time and adverse events were recorded in real time.
Results: Sixty adults (thirty-five men and twenty-five women) with a mean age (and standard deviation) of 45 ± 17 years were randomly enrolled in the study, with thirty patients being managed with each regimen. The average recovery time was 7.8 ± 3.7 minutes following sedation with propofol, compared with 30.7 ± 10.1 minutes following sedation with midazolam/ketamine (p < 0.001). The average total sedation time was 16.2 ± 3.8 minutes for the propofol group, compared with 41.6 ± 10.7 minutes for the midazolam/ketamine group (p < 0.001). The overall rate of respiratory and hemodynamic adverse events was 20% for the propofol group and 10% for the midazolam/ketamine group.
Conclusion: The use of propofol for an orthopaedic procedure requiring sedation in the emergency department expedites patient management and saves time in comparison with the use of midazolam/ketamine.
Procedural sedation with propofol for painful orthopaedic manipulation in the emergency department expedites patient management compared with a midazolam/ketamine regimen: a randomized prospective study, J Bone Joint Surg Am, 2011
Propofol for pain
OK, the patients had received some opioid before the sedation, but like the ones we saw at our anaesthetic department, the opioid dose was usually nowhere near enough to give them proper pain relief, especially not when manipulating the fracture. Still, with fairly low dose propofol sedation, manipulation was easy, with no conscious patient discomfort.
There was a higher incident of adverse respiratory and haemodynamic events with propofol, but in my experience this is also due to propofol often being dosed slightly on the high side as you know the effect will burn off in a short time, and the patient quickly recovers. In our department we used a low dose propofol. Usually a small bolus of 20-30 mg was enough, seldomly 50-60 mg. But this was mainly for sitting up old, frail hip fracture patients to give them a spinal. Worked like a charm.
Anaesthesia and analgesia
This all just adds to the old anaesthetic concept that still holds true, that for proper anaesthesia you need both an anaesthetic and analgesic drug. From Modern Anesthetics, Handbook in Experimental Pharmacology: “profound degrees of hypnosis in the absence of analgesia will not prevent the hemodynamic responses to profoundly noxious stimuli. Also, profound degrees of analgesia do not guarantee unconsciousness. However, the combination of hypnosis and analgesia suppresses hemodynamic response to noxious stimuli and guarantees unconsciousness”.
Still, like the quote implies, there is significant overlap of these effects. The lowered level of consciousness from the anaesthetic blunts the pain response, or at least the conscious experience of it. And as we’ve all seen in patients, analgesia significantly affects the patient’s level of consciousness, not just the patient’s pain response. Very evident in heroine overdose or iatrogenic morphine overdose. And even more so for anyone who’s witnessed a cardiac surgery anaesthesia started with 1000 mcg of fentanyl. Those patients are well anaesthetised.
Yes, we can
Propofol is routinely used for short, painful procedures needing GA, as cardioversion or ECT, again, the lowered level of consciousness blunts the pain response. And for these short durations of pain the patients brief autonomic pain response isn’t of any real concern. This seems to be the case also for short, but painful, orthopaedic manipulations.
So it seems Propofol for short, but painful orthopaedic procedures can be a good alternative. Propofol makes sedation easy to control, is pleasant for the patient, and the patient quickly emerges from the sedation.
The above only holds true for very brief procedures. For any longer, painful procedures always, always add opioids. This includes an often overlooked procedure called intubated ventilation. I’ve seen far too many patients left on propofol as their only infusion after intubation. A tube is painful. Always give an opioid. And outside the theatre don’t just give an opioid bolus, as you or someone else will forget to top up the dose later. Always add opioid as an infusion. /rant