Pulmonary function and respiratory muscle strength at hospital discharge in COVID-19 patients after Intensive Care Unit admission

Abstract

This study describes the pulmonary function and respiratory muscle strength (RMS) at hospital discharge of severe COVID-19 patients, correlating them with peripheral muscle strength, duration of mechanical ventilation (MV), length of hospital stay, and use of medication. A cross-sectional study was conducted with COVID-19 patients admitted to the Intensive Care Unit. Assessment at hospital discharge included the following variables: RMS, pulmonary function, and peripheral muscle strength (Medical Research Council score [MRC] and handgrip dynamometry). A total of 25 patients with mean age of 48.7±12.3 years were assessed. Out of these, 72% presented restrictive ventilatory disorder, in addition to reduced RMS (maximum inspiratory pressure [MIP] of 74% and maximum expiratory pressure [MEP] of 78% of the predicted value). RMS (MIP and MEP, respectively) correlated negatively with duration of MV (r=−0.599, p=0.002; r=−0.523, p=0.007) and length of hospital stay (r=−0.542, p=0.005; r=−0.502, p=0.01); and positively with FVC (r=0.825, p=0.000; r=0.778, p=0.000), FEV1 (r=0.821, p=0.000; r=0.801, p=0.000), PEF (r=0.775, p=0.000; r=0.775, p=0.000), and handgrip strength (r=0.656, p=0.000; r=0.589, p=0.002). At hospital discharge, severe COVID-19 patients presented: reduced RMS; changes in lung function; negative correlation between RMS and duration of invasive mechanical ventilation (IMV), and length of hospital stay; and a positive correlation with lung function and hand grip strength.