Warmed epidural solution halved intrapartum fever, short of its own target

Design

Double-blind randomised controlled trial, single centre

Population

220 nulliparous women at term having epidural labour analgesia

Primary outcome

Intrapartum fever ≥38°C

Effect

15.5% vs 30.9%; RR 0.50 (95% CI 0.30 to 0.84)

This double-blind trial, published in April, randomised 220 nulliparous women having epidural labour analgesia with ropivacaine and sufentanil delivered either at 37°C or at room temperature (22°C), via programmed intermittent bolus and patient-controlled top-ups.

Intrapartum fever of 38°C or more occurred in 15.5% with warmed solution and 30.9% at room temperature (relative risk 0.50, 95% CI 0.30 to 0.84). Maximum temperature was 0.2°C lower. Shivering, block characteristics, labour duration and neonatal outcomes did not differ.

The authors had powered the trial to detect a 60% reduction and judged that the 50% they found did not reach their clinically meaningful threshold. The mechanism by which solution temperature would affect epidural-related fever is unclear, and a single-centre trial needs replication.

Warming the solution is cheap and showed no harm here, but there is not yet enough to make it standard.

• Epidural-related intrapartum fever is common; anticipate it in long labours.
• Warming epidural solution to 37°C is a low-cost option worth discussing locally, pending replication.
• Continue to assess fever in labour for infection rather than attributing it to the epidural.
• No effect on block quality or neonatal outcomes was seen with warmed solution.

Why it matters

Epidural fever leads to antibiotic exposure and neonatal work-ups, so a simple way to reduce it would matter.

Don't overread it

The reduction fell short of the trial's own prespecified clinically meaningful effect.

The statistics, in plain English

A relative risk of 0.50 with an interval from 0.30 to 0.84 is a large and probably real effect in this trial, but the authors set a higher bar in advance. Single-centre trials often overestimate effects.

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