Breathing pattern and respiratory mechanics in chronically tracheostomized patients with chronic obstructive pulmonary disease breathing spontaneously through a hygroscopic condenser humidifier.

Hygroscopic condenser humidifiers (HCHs) have been proposed to artificially condition gases breathed by intubated and mechanically ventilated patients. These devices may improve viscosity and coloring of secretions, preventing further bacterial colonization, and heat inspiratory flow in chronically tracheostomized (CT) patients during spontaneous breathing. The aim of this study was to evaluate the effects of HCH on respiratory mechanics and breathing pattern in CT patients with chronic obstructive pulmonary disease (COPD) breathing spontaneously during quiet breathing and maximal voluntary ventilation (MVV). In a prospective, randomized, controlled study on 21 stable spontaneously breathing CT COPD patients, breathing pattern and respiratory mechanics were evaluated by means of a flow sensor and an esophageal pressure (Pes) catheter during quiet breathing in random order either with or without a HCH connected to the tracheostomy. Six of the patients were also studied during maximal voluntary ventilation (MVV). In comparison to without HCH, the application of HCH did not induce changes in the breathing pattern and respiratory mechanics during quiet breathing. As expected, in comparison to quiet breathing, MVV in 6 patients with HCH induced significant changes in respiratory frequency, minute ventilation, mean inspiratory flow, Pes, work of breathing, pressure time product and index. These changes were not significantly different without the application of HCH. In CT COPD patients spontaneously breathing. HCHs have no significant effects on the breathing pattern and respiratory mechanics both during quiet breathing and MVV.