Can a Sedation Trial Tell Whether Lower Midazolam Use Caused Less Delirium?

A randomized trial can compare entire treatment regimens. Explaining why those regimens differ requires an additional step. A surgical intensive-care study illustrates this distinction with opioid analgesia, midazolam use and delirium.

What the trial randomized

Investigators assigned 105 mechanically ventilated patients to midazolam alone, midazolam with fentanyl, or midazolam with remifentanil. Both opioid groups received less midazolam per day than the control group. The authors reported lower delirium occurrence in the remifentanil group.

Why the mechanism stays open

The trial assigned the regimens rather than randomizing midazolam exposure separately from the opioid. Differences in pain control, sedative dose, sedation depth and other factors could contribute to the observed result. For a review of an individual ICU record, line up medication administration with assessments of sedation and delirium before drawing a causal conclusion.

Liu et al., PLOS One (2017)