- Design
- Parallel-arm, randomised, controlled, non-inferiority trial, single centre
- Population
- 316 elderly patients undergoing unilateral total knee or hip arthroplasty under general anaesthesia, China, January-August 2025
- Primary outcome
- Postoperative delirium within 3 days by Confusion Assessment Method
- Effect
- 9.5% (intranasal, night before) versus 7.6% (intravenous, pre-induction); rate difference 0.02 (95% CI -0.04 to 0.08), meeting the non-inferiority criterion (P<0.001)
Pre-induction intravenous dexmedetomidine is used to reduce postoperative delirium, and it costs theatre time, a line running before induction, and the haemodynamic instability that comes with it. This trial asked whether giving it intranasally the night before is good enough.
A single tertiary centre in China randomised 316 patients from 535 screened, all elderly and scheduled for unilateral total knee or hip arthroplasty under general anaesthesia, between January and August 2025. One group had intranasal dexmedetomidine the night before plus intravenous saline before induction; the other had intranasal saline plus intravenous dexmedetomidine. The primary outcome was delirium within three days, by Confusion Assessment Method.
Delirium occurred in 9.5% of the intranasal group and 7.6% of the intravenous group. The rate difference was 0.02 (95% CI -0.04 to 0.08), meeting the prespecified non-inferiority criterion (P<0.001). The intranasal group also slept better the night before, had lower preoperative anxiety and pain scores, and had significantly fewer adverse events.
The reason this is a practice-changer rather than a curiosity is what it moves. A dose given on the ward the night before removes a pre-induction infusion from the theatre timeline and takes the haemodynamic hit out of the induction window, in exactly the population — elderly, arthroplasty — where that hit is least welcome. It also treats the preoperative sleepless night, which is otherwise untreated and is itself a delirium risk.
- The comparator was an active one — both groups got dexmedetomidine, by different routes
- Fewer adverse events in the intranasal arm is a genuine advantage, not just equivalence
- Improved preoperative sleep is a secondary outcome worth having in its own right
- Single centre, elderly arthroplasty patients — do not extend it to other surgery or younger patients yet
- Ward administration needs a protocol and monitoring; this is not a take-home dose
Why it matters
It moves a delirium-prevention dose out of the theatre timeline and into the night before, where it also treats the sleepless night.
Don't overread it
Non-inferiority within a wide margin is not evidence of equivalence, and this is one centre in one surgical population.
The statistics, in plain English
Non-inferiority asks whether the new approach is not worse by more than a prespecified margin, which is a different and weaker claim than 'as good'. The rate difference of 0.02 with an interval from -0.04 to 0.08 means the intranasal route could genuinely be up to 8 percentage points worse and this trial would not have detected it. With 316 patients and around 9% delirium, that is about what you would expect. The secondary advantages — sleep, anxiety, fewer adverse events — are what make the trade worth considering.
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