Design: Double-blind, randomised, placebo-controlled trial
Population: 120 mechanically ventilated adults on opioid infusions
Primary outcome: Hourly opioid dose (fentanyl equivalents)
Effect: Median 64 vs 77 µg/h; difference −13.0 (95% CrI −26.6 to 2.4)

This double-blind trial at two Melbourne ICUs randomised 120 mechanically ventilated adults already on opioid infusions (excluding cardiac surgery) to low-dose ketamine at 0.15 mg/kg/h or placebo for the duration of ventilation.

Median hourly opioid dose, in fentanyl equivalents, was 64 µg/h with ketamine against 77 µg/h with placebo (median difference −13.0, 95% credible interval −26.6 to 2.4), a 95.1% probability that ketamine reduced opioid use. Delirium and serious adverse events did not differ.

The trial was small and single-country, and the credible interval includes no effect. It supports ketamine as a reasonable opioid-sparing adjunct, and it is cheap and widely available in India, but it does not show fewer ventilator days or better recovery.

Consider low-dose ketamine (about 0.15 mg/kg/h) as an opioid-sparing adjunct in ventilated patients.
Delirium was not increased at this dose in this trial.
Keep sedation targets light and reassess daily, whatever the agents used.
Monitor for hypertension and tachycardia, although serious adverse events were not increased here.

Why it matters

It gives trial support to a common practice of adding ketamine to reduce opioid exposure in the ICU.

The statistics, in plain English

The 95% credible interval of −26.6 to 2.4 µg/h just crosses zero, so no effect cannot be excluded. The 95.1% probability of benefit is a Bayesian statement: given the data and prior, it is very likely ketamine reduced opioid use, but by how much is uncertain.