Impact of continuous positive airway pressure on the pulmonary changes promoted by immersion in water

ABSTRACT

Objective:

To determine whether different levels of CPAP improve the lung volumes and capacities of healthy subjects immersed in water.

Methods:

This was a randomized clinical trial, conducted between April and June of 2016, involving healthy female volunteers who were using oral contraceptives. Three 20-min immersion protocols were applied: control (no CPAP); CPAP5 (CPAP at 5 cmH₂O); and CPAP10 (CPAP at 10 cmH₂O). We evaluated HR, SpO₂, FVC, FEV₁, the FEV₁/FVC ratio, peak expiratory flow rate (PEFR), and FEF_25-75%) at three time points: pre-immersion; 10 min after immersion; and 10 min after the end of each protocol.

Results:

We evaluated 13 healthy volunteers. The CPAP10 protocol reversed the restrictive pattern of lung function induced by immersion in water, maintaining pulmonary volumes and capacities for a longer period than did the CPAP5 protocol.

Conclusions:

When the hemodynamic change causing a persistent lung disorder, only the application of higher positive pressures is effective in maintaining long-term improvements in the pulmonary profile.

Keywords:
Physical therapy modalities; Noninvasive ventilation; Continuous positive airway pressure