Opioid-free Anesthesia: Comment

Challenges in Enhanced Recovery After Surgery (ERAS) research

Despite the general agreement that implementation of Enhanced Recovery After Surgery (ERAS) pathways decrease hospital length of stay, a continuous challenge that has often been neglected is a procedure- and patient-specific approach. For example, asking 'Why is the patient still in hospital?' is the original premise for ERAS. Outcomes improve with increased compliance with recommended elements, but overcomplication of pathways can lead to cherry picking of elements that are convenient, resulting in 'partial ERAS'. As there are few high-quality randomised clinical trials (RCTs) that evaluate the specific role of individual preoperative, intraoperative, and postoperative elements, challenges lie ahead to identify essential ERAS elements to facilitate more widespread implementation. To achieve this goal, the balance between large RCTs and smaller detailed hypothesis-generating observational studies needs to be addressed in order to enhance knowledge and limit waste of research resources.

Opioid-free anesthesia: A systematic review and meta-analysis

STUDY OBJECTIVE

To evaluate all available evidence thus far on opioid based versus opioid-free anesthesia and its effect on acute and chronic postoperative pain.

DESIGN

Systematic review and meta-analysis of randomized clinical trials.

SETTING

Operating room, postoperative recovery room and ward.

PATIENTS

Patients undergoing general anesthesia.

INTERVENTIONS

After consulting MEDLINE, EMBASE and Cochrane database, studies which compared opioid free anesthesia (OFA) with opioid based anesthesia (OBA) were included (last search April 15th 2022).

MEASUREMENTS

Primary outcomes were acute and chronic pain scores in NRS or VAS. Secondary outcomes were quality of recovery and postoperative opioid consumption. Risk of bias was assessed using the RoB2 tool and a random effects model for the meta-analysis was conducted.

MAIN RESULTS

We identified 1245 citations, of which 38 studies met our inclusion criteria. There is moderate quality evidence showing no clinically relevant difference of Numeric Rating Scale (NRS) scores or opioid consumption in the postoperative period (pooled mean difference of 0.39 points with a CI of 0.19-0.59 and 4.02 MME with a CI of 1.73-6.30). We found only one small-sized study reporting no effect of opioid-free anesthesia on chronic pain. The quality of recovery was superior in patients with opioid-free anesthesia (mean difference of 8.26 points), however, this pooled analysis was comprised of only two studies. Postoperative nausea and vomiting (PONV) occurred less in opioid-free anesthesia, but bradycardia was more frequent.

CONCLUSIONS

We concluded that we cannot recommend one strategy over the other. Future studies could focus on quality of recovery as outcome measure and adequately powered studies on the effects of opioid-free anesthesia on chronic pain are eagerly awaited.