A randomized clinical trial comparing an extended-use hygroscopic condenser humidifier with heated-water humidification in mechanically ventilated patients

Study objective: To determine the safety and cost-effectiveness of mechanical ventilation with an extended-use hygroscopic condenser humidifier (Duration; Nellcor Puritan-Bennett; Eden Prairie, Minn) compared with mechanical ventilation with heated-water humidification. Design: Prospective randomized clinical trial. Setting: Medical and surgical ICUs of Barnes-Jewish Hospital, St. Louis, a university-affiliated teaching hospital. Patients: Three hundred ten consecutive qualified patients undergoing mechanical ventilation. Interventions: Patients requiring mechanical ventilation were randomly assigned to receive humidification with either an extended-use hygroscopic condenser humidifier (for up to the first 7 days of mechanical ventilation) or heated-water humidification. Measurements: Occurrence of ventilator-associated pneumonia, endotracheal tube occlusion, duration of mechanical ventilation, lengths of intensive care and hospitalization, acquired multiorgan dysfunction, and hospital mortality. Results: One hundred sixty-three patients were randomly assigned to receive humidification with an extended-use hygroscopic condenser humidifier, and 147 patients were randomly assigned to receive heated-water humidification. The two groups were similar at the time of randomization with regard to demographic characteristics, ICU admission diagnosis, and severity of illness. Risk factors for the development of ventilator-associated pneumonia were also similar during the study period for both treatment groups. Ventilator-associated pneumonia was seen in 15 (9.2%) patients receiving humidification with an extended-use hygroscopic condenser humidifier and in 15 (10.2%) patients receiving heated-water humidification (relative risk, 0.90; 95% confidence interval = 0.46 to 1.78; p = 0.766). No statistically significant differences for hospital mortality, duration of mechanical ventilation, lengths of stay in the hospital or ICU, or acquired organ system derangements were found between the two treatment groups. No episode of endotracheal tube occlusion occurred during the study period in either treatment group. The total cost of providing humidification was $2,605 for patients receiving a hygroscopic condenser humidifier compared with $5,625 for patients receiving heated-water humidification. Conclusion: Our findings suggest that the initial application of an extended-use hygroscopic condenser humidifier is a safe and more cost-effective method of providing humidification to patients requiring mechanical ventilation compared with heated-water humidification.