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Warming Endotracheal Tubes to Body Temperature Reduces Respiratory Adverse Events in Children Undergoing Adenotonsillectomy
Pre-warming polyvinyl chloride endotracheal tubes to 37°C before intubation reduced overall perioperative respiratory adverse event (PRAE) incidence by approximately 10 percentage points compared to room-temperature tubes in children undergoing adenotonsillectomy (14.1% vs. 24.6%, p = 0.039). Room-temperature tube use was independently associated with about twice the odds of experiencing a PRAE (adjusted OR 2.29, 95% CI 1.16–4.54), though this single-center finding requires broader validation before firm conclusions can be drawn.
What Was Studied
This trial investigated whether thermally softening polyvinyl chloride endotracheal tubes by pre-warming them to body temperature (37°C) could reduce the incidence of perioperative respiratory adverse events — including coughing, oxygen desaturation, laryngospasm, and bronchospasm — in children undergoing elective adenotonsillectomy. PRAEs represent a recognized and significant source of morbidity in pediatric airway management, and a practical, equipment-free method of reducing them would have direct implications for routine anesthetic care.
How It Was Studied
This was a prospective, randomized controlled trial enrolling 254 children between 3 and 9 years of age who were scheduled for elective adenotonsillectomy at a single center. Participants were randomly assigned in equal groups to receive intubation with either a standard room-temperature endotracheal tube (Group T1, control) or a tube pre-warmed to 37°C immediately before use (Group T2, intervention). The primary outcome — occurrence of any PRAE — was assessed from the point of extubation through the second postoperative hour. Secondary outcomes included individual PRAE components and perioperative hemodynamic and ventilatory measurements, with independent predictors of PRAEs further explored using multivariable logistic regression.
What Was Observed
- Overall PRAE incidence was meaningfully lower with warmed tubes. Children receiving the pre-warmed tube experienced PRAEs at roughly half the absolute frequency of those in the room-temperature group (14.1% vs. 24.6%, p = 0.039), representing an absolute risk reduction of approximately 10.5 percentage points. Room-temperature tube use independently predicted PRAE occurrence at about twice the odds after adjusting for covariates (adjusted OR 2.29, 95% CI 1.16–4.54).
- Laryngospasm was substantially less frequent with tube warming. The incidence of laryngospasm — one of the more serious PRAE subtypes — was about four times lower in the warmed-tube group (2.3% vs. 8.7%, p = 0.029), suggesting a particular benefit for reducing reflex airway closure following extubation in this surgical population.
- Postoperative coughing also occurred significantly less often. Coughing after extubation, the most commonly observed PRAE in both groups, was nearly halved in relative terms with tube warming (11.7% vs. 21.4%, p = 0.043), indicating a reduction in upper airway irritation across the early recovery period.
- Higher OSA-18 scores independently predicted PRAE risk. Multivariable analysis identified a higher Obstructive Sleep Apnea-18 survey score as a separate predictor of PRAEs, with each unit increase associated with a small but statistically meaningful elevation in odds (adjusted OR 1.04, 95% CI 1.01–1.07), highlighting pre-existing airway vulnerability as a contributing factor.
Why This Matters
Perioperative respiratory adverse events are identified in this study as a major source of morbidity in children undergoing adenotonsillectomy, a procedure performed frequently in the pediatric population. The finding that a simple physical modification — warming the endotracheal tube to body temperature before insertion — can meaningfully reduce these events without additional equipment or pharmacological agents represents a low-barrier opportunity to improve safety in routine pediatric anesthesia practice. The results also open a new line of inquiry into how the thermomechanical properties of standard intubation equipment may influence airway reactivity.
How to Read This Result
While the randomized design and consistent directional findings across PRAE subtypes support cautious optimism, this remains a single-center trial of moderate size, and the biological mechanism by which tube warming reduces airway reactivity has not been established, limiting confidence in the generalizability of these results.
Limitations
The trial was conducted at a single center, which constrains generalizability across different clinical environments, patient populations, and anesthetic practices. The authors explicitly call for multicenter replication to confirm the observed effect. Additionally, the physiological or biomechanical mechanism by which pre-warming the endotracheal tube reduces airway reactivity and PRAE incidence was not investigated or clarified within this study, leaving a key explanatory gap.