Zero-heat flux skin temperature tracks nasopharyngeal temperature during cardiac surgery with cardiopulmonary bypass: a prospective observational study
摘要
Monitoring both nasopharyngeal temperature (TNP) and arterial blood temperature at the CPB arterial outlet is routinely used in cardiac surgery with cardiopulmonary bypass (CPB). We examined the agreement and temperature tracking ability of zero-heat-flux skin temperature (TZHF) compared with TNP in cardiac surgery.
MethodsOf 40 patients scheduled to undergo cardiac surgery with CPB, paired TZHF and TNP measurements were recorded for 33 patients, yielding 8610 measurements across pre-CPB, CPB-cooling, CPB-maintenance, CPB-rewarming, and post-CPB.
ResultsIn the final, trimmed dataset, TZHF and TNP at 30 min after CPB weaning, the primary endpoint, showed similar mean values (35.57 ± 0.69 °C vs. 35.69 ± 0.61 °C; P = 0.181), with a mean difference of –0.12 °C (95% Confidence Interval: –0.29 to 0.06). Bland–Altman analysis showed a small mean bias between TZHF and TNP across all intraoperative phases, ranging from − 0.55 to 0.28 °C. However, the limits of agreement (LOA) exceeded the clinically acceptable ± 0.5 °C during CPB-cooling and CPB-rewarming. Mixed-effects modeling showed considerable between-patient variability in the difference between TZHF and TNP measurements during periods of rapid temperature change. Consistent with the Bland–Altman results, correlation coefficients between TZHF and TNP measurements remained high (ranging from 0.798 to 0.958), and their intraclass correlation coefficients were high (ranging from 0.82 to 0.99) across all intraoperative phases.
ConclusionsOur results indicate that TZHF tracked TNP trends, but its large LOA limits its accuracy and reliability. Simultaneous blood temperature monitoring would enhance TZHF’s effectiveness, as is currently done in cardiac surgery, where both blood temperature and TNP are monitored.
Trial registrationClinicalTrials.gov Identifier: NCT04160845.