This Invited Commentary is part of a Pro and Con debate and accompanies the following articles:
• Lavand’homme P. Opioid-free anaesthesia. Pro: damned if you don’t use opioids during surgery. Eur J Anaesthesiol 2019; 36:247–249.
• Lirk P, Rathmell JP. Opioid-free anaesthesia. Con: it is too early to adopt opioid-free anaesthesia today. Eur J Anaesthesiol 2019; 36:250–254.
A timely Pro and Con debate about opioid-free anaesthesia (OFA) was organised during the 2018 Euroanaesthesia Congress in Copenhagen/DK. We invited lecturers, Prof Patricia Lavand’homme and Prof Philip Lirk, to summarise their presentation1,2 in the European Journal of Anaesthesiology to stimulate critical thinking about both opioid-based-anaesthesia (OBA), the basis of current teaching and practise of anaesthesia, and OFA. Although our specialty is meant to be based on scientific evidence, we all know that practice changes are sometimes driven by the appeal of novelty. It is important to critically evaluate any proposed change to avoid our patients becoming victims of yet another swing of a pendulum. Let us comment on some points made by of both sides of the argument.
Yes indeed, opioids should not be used merely to obtain haemodynamic stability, except in cardiac patients in whom other drugs could have deleterious haemodynamic consequences. We should thus avoid ‘reflex anaesthesia’ where any increase in blood pressure or heart rate induces the administration of another dose of opioid. But maintaining physiological stability during anaesthesia and surgery is one of our basic goals: it needs careful observation and anticipation of the surgeon's action to modify the depth of anaesthesia according to the surgical stimuli and manoeuvres.
The concept of pain, as defined by the International Association for the Study of Pain, should be replaced by that of nociception in patients under general anaesthesia. However, as stated by both authors and others,3 we urgently need reliable tools to evaluate intra-operative nociception. This would allow us to titrate antinociception with an opioid or other nonopioid adjuvant. Current surrogate evaluations of nociception using sympathetic/parasympathetic balance4 or pupil size5 are modified by the intrinsic actions of some of these agents making them unreliable for accurate assessment of nociception. What to do in the meantime? Symptomatic use of beta-blockers or vasodilators to control haemodynamic changes possibly caused by excessive nociception is in my mind not an option: we need to act on the cause of the observed stress response. In case of doubt, the patient should receive a dose of a quick onset analgesic, that is an opioid or ketamine in the current armamentarium of analgesic drugs.
Yes indeed, there exist nonopioid adjuvants (NSAIDs, ketamine, clonidine, dexmedetomidine, lidocaine, gabapentin etc.) that can decrease the need for opioids to achieve adequate intra-operative antinociception or postoperative analgesia. But their opioid-sparing effect in human beings is variable and they have their own contraindications and adverse effects. They should be used in patients or procedures for which their pharmacologic profile is best suited; some of them are short-acting and require a continuous infusion while others are long-acting and could result in delayed awakening. In addition, some also have potentially addictive properties.
Although there is a risk of addiction following the use of opioids, attributing the North American opioid epidemic to the peri-operative use of opioids is probably going a step too far. We must acknowledge that many of us were misled by the message ‘there is no risk of addiction as long as opiates are used to treat pain’ largely diffused in the 1990s. We presently know this is not true both for acute and chronic pain, and that minimising exposure to opiates by using multimodal analgesia is a more effective and safer option. The opioid epidemic would not exist if postoperative opioid prescription had been more cautious, and if patient follow-up and education in their use had been better. The opioid epidemic is of course a source of concern for our specialty but it should not prevent us from using small doses of opioids during or after surgery if deemed necessary. We should not forget, as quoted by Lirk and Rathmell,2 that poorly controlled acute pain is also a potential source of long-term opioid use.
Opioids can produce opioid-induced hyperalgesia. This has been shown with high-dose remifentanil but the evidence is weak in humans when other opioids are used. For example, a prospective historical-control study comparing OBA and OFA (where small-dose rescue opioids were nevertheless allowed) in patients undergoing colorectal surgery did not show any difference in consumption of morphine equivalents and pain scores before hospital discharge despite a dramatic decrease in intra-operative opioid use.6 And it is obvious that decreasing the dose of opioids will decrease the incidence of their adverse effects. But all the nonopioid adjuvants proposed to decrease the need for opioids also have adverse effects and their prescription and administration should be considered carefully as part of the overall risk.
It is indeed possible to provide reliable and safe OFA if general anaesthesia is combined with an effective loco-regional block. But we must keep in mind that short-acting strong analgesics are necessary to prevent acute procedural nociception and its accompanying stress responses (e.g. laryngoscopy). Furthermore, some patients are not eligible for OFA due to, for example, still unknown genetic factors, psychological issues or comorbidities. We agree with the common message of both presenters1,2 that we should aim at decreasing the exposure of our patients to opioids during anaesthesia (opioid sparing anaesthesia) and the postoperative period, by using multimodal general anaesthesia and analgesia.3 But before going further we need to develop reliable tools to measure intra-operative nociception, and to set up well designed randomised controlled trials looking at the peri-operative haemodynamic and metabolic stress responses as well as the short-term and long-term outcomes.
Our daily practice should be based on the latest progress of science (i.e. evidence-based not eminence-proclaimed data), applied to an individual patient based on age, comorbidities, response to the titrated administration of anaesthetic drugs and procedure. Any change in usual practice should be in accordance with the ultimate criteria: should I do/try this on the ones I love most?
Acknowledgements relating to this article
Assistance with the invited commentary: none.
Financial support and sponsorship: none.
Conflicts of interest: none.
Comment from the Editor: this Invited Commentary was checked by the editors but was not sent for external peer review. FV is an Associate Editor of the European Journal of Anaesthesiology.
1. Lavand’homme P. Opioid-free anaesthesia. pro: damned if you don’t use opioids during surgery. Eur J Anaesthesiol
2. Lirk P, Rathmell JP. Opioid-free anaesthesia. con: it is too early to adopt opioid-free anaesthesia today. Eur J Anaesthesiol
3. Brown EN, Pavone KJ, Naranjo M. Multimodal general anesthesia: theory and practice. Anesth Analg
4. Migeon A, Desgranges FP, Chassard D, et al. Pupillary reflex dilatation and Analgesia Nociception Index monitoring to assess the effectiveness of regional anesthesia in children anesthetised with sevoflurane. Paediatr Anaesth
5. Constant I, Nghe MC, Boudet L, et al. Reflex pupillary dilatation in response to skin incision and alfentanil in children anaesthetized with sevoflurane: a more sensitive measure of noxious stimulation than the commonly used variables. Br J Anaesth
6. Brandal D, Keller MS, Lee C, et al. Impact of enhanced recovery after surgery and opioid-free anesthesia on opioid prescriptions at discharge from the hospital: a historical-prospective study. Anesth Analg