This study demonstrates that a multidisciplinary approach to reduce perioperative use of opioids can produce meaningful results when supported by all stakeholders along the perioperative continuum. Moreover, the ability to conduct major abdominal surgery without opioids results in significant reductions in both PACU and hospital LOS, reduced opioid use during hospital admission, and reduced incidence of post-operative nausea/vomiting most associated with opioid use, thereby improving recovery.

The growing use of opioids for the management of acute and chronic pain (Brennan et al. 2007), along with programmes promoting pain as ‘the fifth vital sign’, has been attributed to the increased use of opioid analgesics within the medical community over the past 10–15 years. The fifth vital sign campaign which employed a verbal, numerical pain scoring system (0 = no pain to 10 = intolerable pain) is now a mandatory part of the clinical assessment to establish the ‘adequacy of pain management’ used by most healthcare organizations in the USA, including the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) (Ready et al. 1995). Routine measurement of the fifth vital sign has not, however, been shown to improve the quality of pain management (Mularski et al. 2006; Gan et al. 2014).

This controversial adoption of pain as the ‘fifth vital sign’ has led to significant increases in the average dosages of opioid analgesic medication administered in the early post-operative period after surgery (Aubrun et al. 2003) and increased the incidence of opioid-induced ‘over sedation’ cases by almost 150% (Vila et al. 2005; Lee et al. 2015). Of the patients experiencing life-threatening adverse reactions to opioid analgesics (e.g. respiratory and/or cardiac arrests), 94% had a documented decrease in their level of consciousness preceding the event (White 2017). In 2007, a review article (Brennan et al. 2007) by international experts in pain management further encouraged the more widespread use of opioid-containing analgesics by suggesting that ‘if only we [physicians and nurses] could overcome our “opiophobia”, we would improve pain management’.

The widespread use of opioids to relieve acute pain has unmasked the perverse effects of these analgesics in acute settings. In an editorial, Kehlet and White argued that ‘less may be more’ with respect to use of opioid (narcotic) analgesics (White and Kehlet 2007). These authors strongly argued for using non-opioid analgesics to reduce the dependence on oral and parenteral narcotic analgesics which would lessen the risk of opioid-related side effects. These well-known adverse effects include nausea-vomiting, dizziness, and pruritus, side effects which have been identified by patients as being most worrisome. So much so, that patients would accept experiencing more surgical pain rather than experience the opioid-related side effects of the following: nausea, vomiting, constipation, ileus, bladder dysfunction, pruritis, sedation, visual hallucinations, ventilatory depression, and long-term physical dependence and addiction liability (Gan et al. 2004).

Chronic opioid use is now one of the major social issues facing society today including misuse, abuse, addiction, and unintentional overdose resulting in death. Yet, in spite of all these and for unclear reasons, opioids remain the first line, most commonly used medications to treat pain (Lavand'homme and Steyaert 2017).

Even short-term use of potent opioid analgesics during the intraoperative period can actually aggravate pain due to opioid-induced hyperalgesia (i.e. acute tolerance) (Chia et al. 1999; Hayhurst and Durieux 2016; Zarate et al. 1999). It must be acknowledged that the prevalence of clinical opioid-induced hyperalgesia (OIH) during chronic opioid therapy remains unknown. A hyperalgesia state is often observed in former opioid abusers, especially those undergoing maintenance therapy with methadone, but these reports need to be interpreted cautiously, as opioid addicts’ personality may make determining if a hyperalgesia state exists difficult (Lavand'homme and Steyaert 2017).

Recent work published by Purdon et al. (Santa Cruz Mercado et al. 2023) suggests that reducing opioid use during surgery increases post-operative pain and increased opioid consumption. The authors fail to delineate if all analgesics or solely opioids were removed from the intraoperative period. We must stress here that opioid-free anaesthesia does NOT mean the omission of all classes of analgesics. Our care redesign prioritized non-opioid analgesics to be given first. Perhaps moving forward, the descriptor ‘opioid-free anaesthesia’ should be referred to as ‘non-opioid analgesic anaesthesia’ to highlight this important distinction.

Classic studies have demonstrated that the knowledgeable patient requires less analgesia in the post-operative period and at the same time experiences significantly less pain than the less-informed patient, and more recent investigations have supported the conclusion that preoperative information will aid coping, reduce preoperative anxiety, and may also enhance postsurgical recovery (Kehlet and Wilmore 2002).

Anaesthesiologists are leading experts in pain medicine, and through evidence-based implementations such as ERAS and multimodal anaesthesia, the specialty is helping to address the opioid crisis by reducing the amount of opioid used in the perioperative period whilst still maintaining adequate acute pain control. The time has come to change the foundations of our practice from that of an opioid-based one to that of a multimodal and multidisciplinary practice (Fig. 2), wherein analgesia is managed with non-opioid-based agents first, then layering on alternate non-opioid analgesics, and saving opioids as the capstone in analgesic management (Koepke et al. 2018).

Perioperative physicians and anaesthesiologists should continue to pursue evidence-based research to assist with the opioid epidemic from a broad, perioperative population health approach. We share the responsibility with the rest of the medical community not only to decrease the financial burden on society and on hospitals but also to assist in solving the epidemic, which has now become the number one accidental cause of death in the USA. In addition to the more pragmatic benefits of decreased PACU/hospital LOS, decreased opioid use and fewer opioid-related side effects improve patient outcomes, sometimes substantially — making an ORA/OFA approach favourable from that viewpoint.

We acknowledge several limitations of our study, one being its retrospective nature. Whilst our pathways essentially moved opioids in the position of a ‘rescue’ medication, the lower use of opioids during the post-operative period cannot solely be interpreted as less need for rescue medication, nor can its use suggest increased need. These questions are best answered via prospective study. Moreover, as pain scores were similar between cohorts, we do not know if the administration of opioids was given at the request of the patient or given based on beliefs and biases of members of the care team. Future studies will require not only capturing pain scores specifically but also patient’s expectations on pain, requests by patients for rescue medications, and data on provider’s interpretation and biases in pain management. Another critical limitation of our study is that we do not have access to long-term follow-up care and therefore are unable to report on the long-term use of opioids. Future work will include long-term follow-up to specifically address long-term opioid use as well as functional recovery in these patients.