Intranasal dexmedetomidine the night before surgery was non-inferior for delirium and helped sleep

Design

Single-centre randomised, double-dummy non-inferiority trial

Population

316 older adults having unilateral total knee or hip arthroplasty under general anaesthesia

Primary outcome

Postoperative delirium within 3 days (CAM)

Effect

9.5% intranasal vs 7.6% intravenous; difference 0.02 (95% CI −0.04 to 0.08); non-inferior

Dexmedetomidine reduces postoperative delirium in older patients, but it is usually given as an intravenous infusion before induction, when it can drop heart rate and blood pressure at a busy moment. This single-centre Chinese non-inferiority trial randomised 316 older adults having unilateral hip or knee arthroplasty under general anaesthesia to intranasal dexmedetomidine the night before surgery or intravenous dexmedetomidine before induction, each with a matching placebo.

Delirium within three days (Confusion Assessment Method) occurred in 9.5% with intranasal and 7.6% with intravenous dosing, a difference of 0.02 (95% CI −0.04 to 0.08), meeting the prespecified non-inferiority margin. The intranasal group slept better the night before, had less pre-operative anxiety and pain, and fewer adverse events, with better haemodynamic stability.

Moving prophylaxis to the evening before means better sleep — itself protective against delirium — and removes a haemodynamic hit at induction. The intranasal route is off-label, and the evidence is one single-centre trial. The trial compared two dexmedetomidine strategies; it did not test either against no prophylaxis, and a 2% worse point estimate is within the margin but not nothing.

• Consider intranasal dexmedetomidine the evening before surgery for older patients at risk of delirium having joint replacement, only where overnight ward monitoring is available; the route is off-label and the evidence is one single-centre trial.
• Monitor heart rate and blood pressure after the ward dose, and hold it in bradycardia or hypotension.
• Combine with non-drug delirium prevention: glasses and hearing aids, orientation, sleep, early mobilisation.
• Avoid benzodiazepine premedication in older patients.
• Screen for delirium with a validated tool (CAM or 4AT) for the first three postoperative days.

Why it matters

It moves delirium prophylaxis out of the anaesthetic room and onto the ward, where it also improves pre-operative sleep and anxiety.

Don't overread it

A single-centre non-inferiority trial against another dexmedetomidine regimen; it does not show benefit over no prophylaxis.

The statistics, in plain English

Non-inferiority asks whether the new approach is not worse than the old by more than a chosen margin. The upper confidence limit here (8 percentage points more delirium) fell within that margin, but the true difference could still be a few points worse.

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