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Under-humidification and over-humidification during moderate induced hypothermia with usual devices
François Lellouche1, Siham Qader, Solenne Taille
1INSERM U 651, Université PARIS XII, Service de Réanimation Médicale, AP-HP, Hôpital Henri Mondor, 51 av. du Maréchal de Lattre de Tassigny, 94010 Créteil, France.
Intensive Care Medicine
|June 23, 2006
Summary
During moderate hypothermia in mechanically ventilated patients, heat and moisture exchangers under-humidify airways. Heated humidifiers may over-humidify, suggesting cautious use of both devices.
Area of Science:
- Critical Care Medicine
- Respiratory Physiology
- Mechanical Ventilation
Background:
- Adequate airway humidification is crucial for mechanically ventilated patients, especially during therapeutic hypothermia.
- The efficacy of standard humidification devices under hypothermic conditions remains poorly understood.
Purpose of the Study:
- To evaluate the performance of different airway humidification systems during moderate hypothermia in mechanically ventilated patients.
- To compare heat and moisture exchangers (HMEs) and heated humidifiers (HHs) under induced hypothermia.
Main Methods:
- Prospective, cross-over randomized study conducted in a Medical Intensive Care Unit.
- Nine adult patients undergoing mechanical ventilation with induced moderate hypothermia (33°C).
- Comparison of ventilation with a standard HME, a heated humidifier (HH), and an active HME.
Main Results:
- All humidification systems showed limitations during hypothermia.
- Standard HMEs resulted in significant under-humidification (absolute humidity < 25 mgH2O/L), with performance correlated to core temperature.
- HHs were generally adequate but risked over-humidification at recommended settings.
Conclusions:
- Heat and moisture exchangers should be used with caution in patients with moderate hypothermia due to inadequate humidification.
- Heated humidifiers may lead to excessive airway moisture, necessitating careful adjustment of settings during hypothermia.
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