Dexmedetomidine up the nose the night before, instead of a drip on the day

Design

Parallel-arm randomised non-inferiority trial, single centre

Population

316 elderly patients undergoing elective unilateral total knee or hip arthroplasty under general anaesthesia

Primary outcome

Postoperative delirium within 3 days (Confusion Assessment Method)

Effect

9.5% intranasal vs 7.6% intravenous; rate difference 0.02 (95% CI −0.04 to 0.08), non-inferiority met (P<0.001)

Three hundred and sixteen older patients having elective knee or hip arthroplasty were randomised to intranasal dexmedetomidine the night before surgery with saline before induction, or saline intranasally and an intravenous dexmedetomidine infusion before induction. Delirium in the first three days, assessed by the Confusion Assessment Method, occurred in 9.5 per cent of the intranasal group and 7.6 per cent of the intravenous group — a difference of 0.02, within the pre-specified non-inferiority margin.

The secondary findings are what would make a ward change its practice. The intranasal group slept better the night before, were less anxious, reported less preoperative pain, and had fewer adverse events, which in a dexmedetomidine trial usually means bradycardia and hypotension around induction.

This is a single-centre Chinese trial with an open route difference that cannot be blinded to the ward staff giving it, and a delirium rate assessed for only three days. It is a reason to look at the approach, not to rewrite a protocol on.

• Treat the night before as part of the delirium pathway, not only the day of surgery.
• Ask what actually disturbs sleep on your ward — observations, lighting, noise — before adding a drug to fix it.
• Non-inferiority here was against active treatment, not against no prophylaxis.
• Watch heart rate and blood pressure whichever route is used; the margin of benefit was in adverse events.
• Delirium was assessed to day three only; later delirium was not captured.

Why it matters

It moves delirium prophylaxis out of the anaesthetic room and into the evening before.

Don't overread it

Single-centre, open-label by necessity, and with no placebo arm — neither route is shown to prevent delirium.

The statistics, in plain English

A non-inferiority trial asks whether the new option is not worse by more than a set margin — it never shows the two are equal, and it cannot show either works. The rate difference of 0.02 with an interval from −0.04 to 0.08 sits within the chosen margin, so non-inferiority is claimed; the upper bound still allows the intranasal route to be 8 percentage points worse in absolute terms, which is a matter of how the margin was chosen.

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