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Clinical Investigations in Critical CareSafety of Combined Heat and Moisture Exchanger Filters in Long-term Mechanical Ventilation
Section snippets
Study Design
This study took place during an 18-month period in the medical ICU of a large teaching hospital. Advantage was taken of a recent institutional decision to introduce HMEFs into the daily practice of respiratory care in this ICU, so that approval by the local ethical committee was not sought. During the study period, each patient with an indication for mechanical ventilation was considered for inclusion at the time of intubation or at ICU admission if already intubated. Subjects who were
RESULTS
Two hundred thirty-seven consecutive patients were randomized; 115 continued to receive mechanical ventilatory assistance for at least 48 h, 59 in the HMEF group and 56 in the HWBH group.
The two groups were comparable in terms of gender ratio, primary abnormality, and severity of illness as determined from the SAPS score (Table 1, left). On the average, patients in the HWBH group were slightly older than those in the HMEF group (p<0.02). There were six crossovers from HMEF to HWBH, four
DISCUSSION
The safety of heat and moisture exchangers for long-term use in mechanical ventilation has not been well defined. Concern is legitimate, considering that these devices may not condition inspired air quite as well as HWBHs do,18 and have indeed been associated with an increased incidence of ETT obstruction.13, 14, 15 One controlled trial of HMEF vs HWBH was even discontinued following one death related to this latter complication in one patient using an HMEF.14 A common denominator to all these
ACKNOWLEDGMENTS
The authors wish to thank the ICU staff, especially Cathy Grant, RRT, and Camille Anglada, for their outstanding technical help. We are also grateful to Antonijeta Peric for her patience in reading the tracheal aspirate smears.
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