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Abstract

Introduction: Natural warming and humidification of the inspired air tend to be decreased in mechanical ventilation (MV) patients. The goal of this work was to evaluate the effect of humidity on lung mechanics (compliance, functional residual capacity (FRC), and airway resistance (RAW) in a canine experimental model with long-term mechanical ventilation. Materials and methods: Ten dogs were subjected to 24-hours mechanical ventilation as follows: Group I (n = 5): mechanical ventilation with dry air. Group II (n = 5): mechanical ventilation with air from a humidifier chamber. Results: Lung compliance was found to decrease in a higher rate for Group I than for Group II (ANOVA p = NS), while FRC decreased in both groups (ANOVA p = NS), with a lower rate for Group I. RAW values increased in both groups, with a lower rate for Group II (ANOVA p = NS). Conclusions: There were no significant differences in ventilatory mechanics with dry air compared to air from a humidifier chamber.

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