Bissonnette 1989b.

Methods	Randomized parallel study comparing HME to HH.
Participants	Inclusion criteria: infants and children weighing 5‐30 kg, ASA status I or II, having peripheral surgery lasting 1‐3 hr. Mean age: HME 4 years, HH 5 years. Exclusion criteria: without history of tympanic or middle ear problems. Respiratory diagnosis: not stated. Severity: ASA status I or II. Setting: paediatric hospital, Canada.
Interventions	HME (hygroscopic): Humid‐Vent (Gibeck). n = 8. HH: MR450 (Fisher & Paykel) set at 37 ºC. n = 10. Time in study: 120 min.
Outcomes	Change in body temperature.
Notes	Funding: not stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated.
Allocation concealment (selection bias)	Unclear risk	Not stated.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Number enrolled not stated.
Selective reporting (reporting bias)	Unclear risk	No protocol available.
Other bias	Low risk	None identified.