The physical function intensive care test: implementation in survivors of critical illness

Recent studies have demonstrated safety, feasibility, and decreased hospital length of stay for patients with weakness acquired in the intensive care unit (ICU) who receive early physical rehabilitation. The scored Physical Function in Intensive Care Test (PFIT-s) was specifically designed for this population and demonstrated excellent psychometrics in an Australian ICU population. The purpose of this study was to determine the responsiveness and predictive capabilities of the PFIT-s in patients in the United States admitted to the ICU who required mechanical ventilation (MV) for 4 days or longer. This nested study within a randomized trial administered the PFIT-s, Medical Research Council (MRC) sum score, and grip strength test at ICU recruitment and then weekly until hospital discharge, including at ICU discharge. Spearman rho was used to determine validity. The effect size index was used to calculate measurement responsiveness for the PFIT-s. The receiver operating characteristic curve was used in predicting participants' ability to perform functional components of the PFIT-s. From August 2009 to July 2012, 51 patients were recruited from 4 ICUs in the Denver, Colorado, metro area. At ICU discharge, PFIT-s scores were highly correlated to MRC sum scores (rho=.923) and grip strength (rho=.763) (P