A heat and moisture exchanging filter in long-term ventilation.

We report our experience of using the Pall BB50T heat and moisture exchanging filter (HMEF) in critically ill patients undergoing long-term ventilation. Three hundred and sixty-four ventilated patients humidified with the Pall HMEF were studied prospectively. Thirty-five patients (mean APACHE II score 24.6, mean predicted mortality 50.9%) were ventilated for more than 10 days (mean 18.9), accounting for 661 patient-ventilated days. During this period two patients suffered tracheal tube occlusion. No other complications could be attributed to the filter. We conclude that the Pall BB50T heat and moisture exchanging filter is safe in patients undergoing long-term ventilation. However, its use demands a high degree of respiratory care.