BACKGROUND Monitoring peri-operative body temperature in children is currently mainly achieved through invasive devices. The Temple Touch Pro Temperature Monitoring System estimates core temperature noninvasively based on heat flux thermometry. OBJECTIVE To investigate the agreement of this noninvasive sensor against standard oesophageal core temperature. DESIGN A prospective observational study. SETTING University hospital recruiting between April and July 2021.PATIENTS One hundred children (32 girls) aged 6 years or younger scheduled for noncardiac surgery, resulting in 6766 data pairs. Exclusion criteria were contraindication for the insertion of an oesophageal temperature probe, and procedures in which one of the measurement methods would interfere with the surgical field.MAIN OUTCOME MEASURES Primary outcome was the agreement analysis by a Bland-Altman comparison with multiple measurements. Posthoc, we performed another agreement analysis after exclusion of a statistically determined equilibration time. Secondary outcomes were the temperature differences over time and subgroup analysis of hypothermic, normothermic and hyperthermic temperature ranges, age, sex and sensor's side by type III analysis of variance. Further, we correlated the sonographically determined depth of the artery with trueness. RESULTSThe mean difference was -0.078C (95% CI -0.15 to R0.05) with limits of agreement of -1.00 and R0.858C. After adjusting for an equilibration time of 13 min, the mean difference improved to -0.048C (95% CI -0.08 to R0.01) with limits of agreement of -0.68 and R0.608C. Concordance correlation coefficient was 0.83 (95% CI 0.82 to 0.84). Differences between the skin sensor and oesophageal reference increased over time by -0.058C per hour. Subgroup analysis showed no clinically relevant differences. Depth of artery negatively correlated with trueness by 0.038C per millimetre.CONCLUSIONS Although the Temple Touch Pro sensor showed acceptable accuracy after allowing for an equilibration time, it still needs further investigation for routine use in children. This particularly affects accuracy in hypothermic ranges, imprecise positioning and applicability in children with immature or vulnerable skin.

Background: Maintenance of normothermia is an important quality metric in pediatric anesthesia. While inadvertent hypothermia is effectively prevented by forcedair warming, this therapeutic approach can lead to iatrogenic hyperthermia in young children. Aims:To estimate the influence of external warming by forced air on the development of intraoperative hyperthermia in anesthetized children aged 6 years or younger. Methods:We pooled data from two previous clinical studies. Primary outcome was the course of core temperature over time analyzed by a quadratic regression model. Secondary outcomes were the incidence of hyperthermia (body core temperature >38°C), the probability of hyperthermia over the duration of warming in relation to age and surface-area-to-weight ratio, respectively, analyzed by multiple logistic regression models. The influence of baseline temperature on hyperthermia was estimated using a Cox proportional hazards model.Results: Two hundred children (55 female) with a median age of 2.1 [1 st -3 rd quartile 1-4.2] years were analyzed. Mean temperature increased by 0.43°C after 1 h, 0.64°C after 2 h, and reached a peak of 0.66°C at 147 min. Overall, 33 children were hyperthermic at at least one measurement point. The odds ratios of hyperthermia were