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.

摘要
本研究描述了重症新型冠状病毒肺炎（COVID-19）患者出院时的肺功能与呼吸肌强度（respiratory muscle strength, RMS），并将其与外周肌肉力量、机械通气（mechanical ventilation, MV）时长、住院时长及药物使用情况进行相关性分析。本研究针对收治于重症监护病房（Intensive Care Unit, ICU）的COVID-19患者开展了一项横断面研究。出院时的评估指标包括：RMS、肺功能与外周肌肉力量（医学研究委员会评分[Medical Research Council score, MRC]及握力测定）。本研究共纳入25例患者，其平均年龄为48.7±12.3岁。其中72%的患者存在限制性通气障碍，同时伴随RMS降低（最大吸气压[maximum inspiratory pressure, MIP]为预测值的74%，最大呼气压[maximum expiratory pressure, MEP]为预测值的78%）。
RMS（分别对应MIP与MEP）与MV时长（r=-0.599，P=0.002；r=-0.523，P=0.007）及住院时长（r=-0.542，P=0.005；r=-0.502，P=0.01）呈负相关，与用力肺活量（forced vital capacity, FVC）（r=0.825，P=0.000；r=0.778，P=0.000）、第一秒用力呼气容积（forced expiratory volume in one second, FEV1）（r=0.821，P=0.000；r=0.801，P=0.000）、峰流速（peak expiratory flow, PEF）（r=0.775，P=0.000；r=0.775，P=0.000）及握力（r=0.656，P=0.000；r=0.589，P=0.002）呈正相关。
出院时，重症COVID-19患者表现为：RMS降低、肺功能异常；RMS与有创机械通气（invasive mechanical ventilation, IMV）时长及住院时长呈负相关；且与肺功能及握力呈正相关。