- Design
- Randomised, double-blind, placebo-controlled trial, single centre
- Population
- 356 men (ASA I–II) having elective ureteroscopy
- Primary outcome
- Incidence of intraoperative penile erection
- Effect
- 6.2% vs 21.9% (RR 0.28, 95% CI 0.15 to 0.53)
In a single-centre, double-blind trial, 356 men having elective ureteroscopy under general anaesthesia were randomised to intravenous esketamine 0.3 mg/kg or saline before induction.
Intraoperative erection occurred in 6.2% with esketamine and 21.9% with placebo (RR 0.28, 95% CI 0.15 to 0.53; number needed to treat about 6). Erections needing rescue treatment fell from 21.3% to 4.5%. Blood pressure and heart rate were slightly higher with esketamine, recovery was similar, no hallucinations occurred, and catheter-related bladder discomfort was milder.
Intraoperative erection can stop a procedure and risks urethral injury, and current management is largely reactive. A cheap single prophylactic dose that prevents most episodes is attractive. It is one centre's trial, and esketamine availability varies; racemic ketamine was not tested. Discuss with the anaesthetic team before adopting it.
- Consider prophylactic low-dose esketamine for men having ureteroscopy under general anaesthesia
- Agree the protocol with your anaesthetic team before routine use
- Monitor blood pressure and heart rate, which rose slightly
- Note that racemic ketamine was not tested; do not assume equivalence
- Keep rescue options ready, as erections were reduced, not abolished
Why it matters
It offers prevention for a disruptive complication usually handled only after it starts.
Don't overread it
A single-centre trial in healthy (ASA I–II) men; confirmation in larger, multicentre trials is needed.
The statistics, in plain English
An RR of 0.28 means erections were about a quarter as common. A number needed to treat of about 6 means treating six men prevents one erection.
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