Evaluation of the efficiency of heat and moisture exchangers during paediatric anaesthesia
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Published on: November 21, 2017
M Luchetti1, A Pigna, A Gentili
1Department of Anaesthesia and Intensive Care, Fatebenefratelli and Ophtalmiatric Hospital, Milan, Italy.
Insights
Heat and moisture exchangers (HMEs) used in pediatric anesthesia did not adequately warm or humidify breathing gases. While conserving efficiency was good, HMEs failed to meet essential standards for patient safety during anesthesia.
Area of Science:
- Anesthesiology
- Respiratory Care
- Pediatric Medicine
Background:
- Maintaining optimal airway humidity and temperature is crucial during anesthesia, particularly in pediatric patients.
- Heat and Moisture Exchangers (HMEs) are commonly used devices to achieve this, but their efficacy in children requires thorough evaluation.
Purpose of the Study:
- To assess the efficiency of Hygrobaby and Hygroboy HMEs in providing adequate humidification and warming for pediatric patients during anesthesia.
- To determine if HMEs meet established standards for inspired gas temperature and humidity in infants and children.
Main Methods:
- Eighteen pediatric patients were divided into two groups based on weight (infants up to 10 kg and children above 10 kg), each using a specific HME.
- Key parameters including body temperature, room temperature, fresh gas temperature, HME warm-up time, and inspired/expired gas temperature and humidity were measured.
- Conserving efficiency was calculated, and correlations between efficiency and various temperature parameters were analyzed.
Main Results:
- Inspired gas temperatures consistently remained below 30°C in both groups.
- Inspired absolute humidity did not exceed 28 mgH2O/L.
- Conserving efficiency of the HMEs was high (0.93) and positively correlated with fresh gas temperature.
Conclusions:
- Despite satisfactory conserving efficiency, the evaluated HMEs failed to meet minimum standards for humidification and warming in pediatric anesthesia.
- Findings suggest a need for improved HME technology or alternative strategies to ensure adequate airway conditioning in children undergoing anesthesia.
Abstract:
This study evaluates the efficiency of heat and moisture exchangers (HMEs) in allowing adequate humidification and warming during anaesthesia in children. Eighteen paediatric patients undergoing anaesthesia were divided into two groups: group A ten patients: infants up to 10 kg-->Hygrobaby HME; group B 8 patients: children above 10 kg-->Hygroboy HME. The following parameters were evaluated: body temperature (bT), room temperature (rT), fresh gas temperature, HME warm-up time, inspired and expired gases temperature and humidity, conserving efficiency, and duration of anaesthesia. Gas temperatures were recorded by means of a recorder fitted with four thermal probes. Humidity values were mathematically derived. The correlation between efficiency and rT, bT, and fresh gas temperature was computed. In both groups the inspired gases temperatures were below 30 degrees C. Inspired absolute humidity was never more than 28 mgH2O.l(-1). The conserving efficiency was good (0.93 in both groups). A positive correlation was found between efficiency and fresh gas temperature. HMEs did not meet the minimum standards for humidity and heating during anaesthesia in children, although their conserving efficiency was found to be satisfactory.
