Abstract
BACKGROUND: This study sought to confirm eligibility criteria, compare costs, and evaluate the effects of humidification technique on circuit colonization and nosocomial pneumonia in mechanically ventilated patients. MATERIALS & METHODS: After evaluation, patients eligible for use of a passive humidifier (n = 200) were randomized to receive either a hygroscopic condenser humidifier (HCH) or heated humidifier and heated-wire circuit (HWC), Group A. Patients ineligible for Group A (Group B) were randomized to receive heated humidification with HWC or without a heated-wire circuit (NHWC). Maximum and minimum body temperature, number of suctioning procedures, secretion volume, secretion quality, volume of instilled saline, number of times circuit was drained, and the number of circuit disconnections were recorded daily, and costs of devices and maintenance were calculated. Sputum, ventilator circuits, and humidification devices of patients requiring > 24 hours of ventilatory support were swabbed and cultured. Incidence of tracheal tube occlusion and of nosocomial pneumonia were also recorded. RESULTS: Of the patients, 51.5% were eligible for HCH. Surgical patients were more likely to meet criteria for HCH use than were medical patients (67% vs 19%, p< 0.001). Ineligibility for HCH use was based on the presence of thick (63%) or bloody secretions (22%), hypothermia (8%), or a combination of these conditions (7%). Patients in Group B were sicker, required ventilatory support longer, and had thicker and greater volumes of secretions. Nosocomial pneumonia was more likely in Group-B patients but was similar between humidification devices within each group. Circuit disconnections were greatest in the NHWC group. Costs were significantly less for HCH on Day 1 ($5.23 vs HWC = $30.22 vs NHMC = $27.79, p < 0.001). On Day 5, costs/day still favored HCH ($4.70 vs $8.97 vs $17.96, p < 0.01). No incidence of tube occlusion was seen. CONCLUSIONS: HCH use in surgical patients can be safe and effective (67%). Medical patients are less likely to be eligible for HCH use (19%). For 1 day's use, HCH is significantly less costly than the other techniques. After 5 days, costs of HCH and HWC diminish, whereas costs of NHWC remain high. An algorithm that directs choice based on patient need helps assure safe, effective humidification. Humidification devices do not influence the incidence of nosocomial pneumonia. [Respir Care 1996;41(9):809-816]
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