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

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 FEF25-75%) 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.