Airway humidification with a heat and moisture exchanger in mechanically ventilated neonates : a preliminary evaluation.

OBJECTIVE

We set out to evaluate the efficacy of passive inspiratory gas conditioning in mechanically ventilated neonates and compared it with that of a heated humidifier (HH).

DESIGN

Prospective, randomized, controlled study.

SETTING

Neonatal and pediatric intensive care unit.

PATIENTS

Fourteen mechanically ventilated neonates nursed in incubators.

INTERVENTIONS

The HH was set to deliver a temperature of 37 degrees C and an absolute humidity of 40 mgH(2)O/l at the incubator entrance. Inspired temperature (T degrees ) and absolute humidity (AH) were measured by the psychometric method, transpulmonary pressure (Tpres) by means of a differential pressure transducer. Measurements were performed at 5, 10, and 15 min.

MEASUREMENTS AND RESULTS

The values of T degrees were significantly higher using the HH (34.6+/-1.6 degrees C) than the heat and moisture exchanger (HME) (33.8+/2.3, p<0.001). The values of AH were significantly higher using the HH (36.6+/-2.5 mgH(2)O/l) than the HME (32.4+/-2.8 mgH(2)O/l, p<0.001). No significant changes were observed in transpulmonary pressure. A significant positive correlation was observed between incubator temperature and the temperature delivered by the HH (R(2)=0.61, p<0.001).

CONCLUSIONS

The use of HMEs in neonates made it possible to achieve an absolute humidity of 28 mgH(2)O/l or more and a temperature of 30 degrees C or more. Higher values are obtained using a HH.