Intranasal dexmedetomidine the night before was non-inferior to the drip on the day

Design

single-centre, parallel-arm randomised controlled non-inferiority trial

Population

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

Primary outcome

postoperative delirium within 3 days by Confusion Assessment Method

Effect

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

Three hundred and sixteen patients having elective unilateral knee or hip arthroplasty under general anaesthesia at one Chinese tertiary hospital were randomised to intranasal dexmedetomidine the night before surgery plus intravenous saline at induction, or intranasal saline the night before plus intravenous dexmedetomidine before induction. The primary outcome was delirium within three days, assessed by the Confusion Assessment Method.

Delirium occurred in 9.5 per cent of the intranasal group and 7.6 per cent of the intravenous group. The rate difference was 0.02 (95% CI −0.04 to 0.08), which met the pre-specified non-inferiority criterion. The intranasal group also slept better the night before surgery, reported less preoperative anxiety and pain, and had significantly fewer adverse events — the last presumably reflecting the haemodynamic effects of an intravenous infusion given immediately before induction.

The practical appeal is the route. An intranasal dose on the ward the night before needs no line, no infusion pump and no anaesthetist at the bedside, which makes it deliverable where a pre-induction infusion is not. The caution is that non-inferiority against an active comparator says nothing about whether either approach beats no dexmedetomidine at all, and there was no untreated arm here.

• Consider intranasal dexmedetomidine the night before where a pre-induction infusion is impractical
• Note the secondary gains: better preoperative sleep, less anxiety, fewer adverse events
• Do not read this as evidence that dexmedetomidine prevents delirium — there was no untreated arm
• Monitor as you would for any sedative given on a ward overnight
• Confirm the delirium assessment on your unit uses a validated tool, as this trial did

Why it matters

It moves a delirium-prevention step off the anaesthetic room and onto the ward.

Don't overread it

A single-centre non-inferiority trial against an active comparator — no placebo arm, so neither route is shown to reduce delirium.

The statistics, in plain English

Non-inferiority means the intranasal route was not meaningfully worse within a pre-set margin — the confidence interval for the difference (−0.04 to 0.08) includes the possibility that it is slightly worse as well as slightly better. Because both arms received the drug, this trial cannot say whether either prevented delirium relative to doing nothing.

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