Delirium after surgery: opioid-sparing anesthesia appears to reduce the risk

What the researchers compared

The review includes 7,852 adult surgical patients. The trials compared opioid-free or opioid-sparing anesthesia using ketamine, esketamine or dexmedetomidine with a placebo, conventional opioid-based anesthesia or standard care.

The primary outcome was postoperative delirium. The abstract describes it as a neurocognitive complication associated with greater morbidity, long-term cognitive decline and death. It does not specify the monitoring periods used in the different trials.

An overall favorable result, but with variation

Delirium was observed in 488 of the 4,013 patients receiving the strategies studied, compared with 633 of the 3,839 patients in the control groups. The pooled analysis reports a relative risk of 0.641, with a 95% confidence interval of 0.525 to 0.784.

This overall result favors opioid-sparing strategies. However, between-trial heterogeneity, measured by an I² of 52.2%, indicates that their results are not uniform. The abstract does not allow precise identification of the surgical settings or patient profiles that would benefit most from these approaches.

Esketamine shows no statistically established benefit

In the analyses by drug, dexmedetomidine shows a favorable result with a confidence interval that excludes no effect. This is not the case for esketamine or ketamine: their intervals include that possibility.

This distinction qualifies the authors’ conclusion, which lists esketamine among the options with the most consistent benefits. The figures in the abstract are insufficient to establish its effectiveness for this outcome. These subgroups also do not demonstrate that one drug is superior to the others.

What this review cannot determine

The strategies studied change both opioid exposure and the accompanying medications. Based on the abstract, it is impossible to attribute the benefit solely to opioid reduction.

The abstract does not detail adverse effects or the quality of pain control. Reducing delirium is an important outcome, but is not enough to determine the best balance of benefits and risks for an anesthetic approach.

What we can take away

This review supports the potential value of opioid-sparing anesthesia in reducing postoperative delirium, without justifying routine opioid elimination or establishing the effectiveness of each drug.