Maximal expiratory pressure predicts mortality in patients hospitalized in medical and surgical wards

Background: the prognostic value of maximal inspiratory and expiratory pressures on functional capacity and mortality of hospitalized patients are not well established. Aim: to evaluate the prognostic value of respiratory pressures in hospitalized patients. Methods: patients admitted to a general hospital in Santiago-Chile were prospectively studied. Within 48 hours of admission, handgrip strength and inspiratory and expiratory pressures were measured. Subjective global assessment of nutritional status (SGA) was determined and Apache II score was calculated. Functional status was assessed using the Karnofski index. Patients were followed for a period of 30 days. Mortality and decline in functional capacity, defined as a reduction in at least two stages of the Karnofski index were determined. Normal values for handgrip strength and respiratory pressures were obtained in 366 healthy subjects aged 20 to 89 years, thus the results obtained in patients were expressed as age and sex matched z-scores. Results: one hundred and eight patients were recruited and 18 had to be excluded. Thus, 90 patients aged 58 ± 16 years (46 females) were studied. During the observation period, six patients died and nine experienced a decline in functional status. Patients who died had significantly lower maximal inspiratory and expiratory pressures, hand grip strength and worse SGA. Logistic regression analysis only accepted maximal expiratory pressure expressed as z-score as a predictor of mortality. In addition, it was the only significant predictor of death or functional decline. Conclusions: maximal expiratory pressure on admission was a predictor of death or functional decline at 30 days.