Development of a physical function outcome measure (PFIT) and a pilot exercise training protocol for use in intensive care

Abstract

Objective: To develop an outcome measure as a basis for prescribing and evaluating rehabilitation in the critically ill, and to measure its reliability and responsiveness to change. The study also aimed to assess the feasibility and safety of a pilot exercise training protocol in an intensive care unit.

Methods: We developed a battery of tests (the Physical Function ICU Test [PFIT]) to measure endurance, strength, cardiovascular capacity and functional level. Patients with a tracheostomy who were mechanically ventilated were recruited from a medical-surgical ICU and respiratory weaning unit at a tertiary referral hospital in Melbourne, Victoria, between 2003 and 2005. Patients underwent a pilot exercise training protocol and performed the PFIT when able to stand, and again after weaning from ventilation.

Results: The PFIT demonstrated good reliability and was responsive to change. Twelve patients completed testing and exercise sessions with no adverse events; 50 of 63 possible training sessions (79%) were delivered. Participants increased the marching on the spot result by a mean difference of 86.3 steps and 56 s (P < 0.05), and the shoulder flexion result by 8 repetitions (P < 0.05). Improvement in function and muscle strength was also observed (P < 0.05). Inter-rater reliability for the PFIT was good (intra-class correlation coefficient, 0.996-1.00).

Conclusions: The PFIT is a reliable and responsive outcome measure, and the pilot training protocol was safe and feasible. As exercise may attenuate weakness and functional impairment, the PFIT can be used to prescribe and evaluate exercise and mobilisation. Future research should aim to develop a PFIT score and investigate the ability of the PFIT to predict ICU readmission risk and functional outcome.