Effect of hypophosphatemia on the withdrawal of mechanical ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease

Mechanical ventilation (MV) is a life-supporting modality frequently performed in critically ill patients to mechanically assist or replace spontaneous breathing. The aim of this study was to investigate the effect of hypophosphatemia on the withdrawal of MV in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). The medical records of 67 AECOPD cases, treated with MV between 2011 and 2013, were analyzed retrospectively. The patients were assigned to the hypophosphatemic and the normophosphatemic groups according to their serum phosphate levels (with the threshold of 0.87 mmol/l). The results showed that the morbidity rate of hypophosphatemia in these AECOPD patients was 56.72%. A significantly higher percentage of failure-to-wean from MV was observed in the hypophosphatemia group vs. the normophosphatemic group (34.21 vs. 10.34%, P<0.05). Furthermore, hypophosphatemia was associated with respiratory muscular weakness, as reflected by a decrease in the tidal volume of spontaneous respiration, reduced static lung compliance and impaired pulmonary function, leading to weaning failure. The findings suggested that hypophosphatemia significantly affected the weaning from MV in AECOPD patients. Serum phosphorus levels may therefore serve as a reference index to determine the success of weaning.