Lung and respiratory muscle function at discharge from a respiratory intensive care unit

Background. The purpose of this prospective observational study was to describe lung and respiratory muscle function at Respiratory Intensive Care Unit (RICU) discharge after a severe exacerbation of Chronic Obstructive Pulmonary Disease (COPD). Methods. The study was conducted in 42 consecutive COPD patients in whom arterial blood gases, dynamic and static lung volumes, maximal inspiratory pressure (MIP) were assessed at discharge from the RICU and compared with values measured 6 months previously when they were in a stable state. The same measurements were performed at 6-month interval in 42 comparable stable COPD patients not requiring any hospitalisation for at least 6 months used as controls. Results. 24% of patients in the study group were discharged with hypercapnia whereas they were normocapnic before the acute episode. Compared to prior to exacerbation, patients of study group showed a significant worsening in mean values of PaCO2 (p=0.005), MIP (p=0.005) and FEV1 (p=0.041). Predefined criteria of worsening in PaCO2, MIP and FEV1 were observed in 47%, 33% and 28% of patients in study respectively. Neither lung nor respiratory muscle function in last stable state did predict post RICU functional worsening. In a period of 6 months controls showed no change in the studied parameters. Conclusions. After a severe acute exacerbation requiring admission to a RICU and immediately before discharge 1) a large proportion of COPD patients still show preserved lung and respiratory muscle function 2) more than one third of them would require further care and rehabilitative attempts to restore functional derangements.