Muscle strength and endurance to predict successful extubation in mechanically ventilated patients: A pilot study evaluating the utility of upper-limb muscle strength and ergometry

Background. Successful extubation of mechanically ventilated patients is essential for the physiotherapist to succeed in respiratory rehabilitation of the patient. Delay in the weaning process increases the complication rate of mechanical ventilation. A variety of parameters are used as predictors of extubation readiness, but the association between muscle strength (deltoid, neck flexor muscle group and trapezius), endurance and extubation readiness has not been determined.  Objectives. The aim of the study was to determine if muscle strength and endurance can be used as possible predictors of successful extubation in mechanically ventilated patients. The objectives were to determine if muscle strength measured with the Oxford grading scale can be used as a possible predictor, and if muscle endurance measured with the MOTOmed letto2 cycle ergometer can be used as a possible predictor.  Methods. During the pilot study, 37 subjects were recruited. Deltoid, neck flexors and trapezius muscle strength was tested using the Oxford grading scale and respiratory muscle strength using maximum inspiratory and expiratory pressures. Endurance was determined by riding the MOTOmed letto2 cycle ergometer for 5 minutes with the upper limbs.  Results. Muscle strength of the deltoid and the neck flexor muscle group tested with the Oxford grading scale was associated with successful extubation respectively, ( p =0.022; p =0.019). Muscle endurance tested with the MOTOmed letto2 cycle ergometer also demonstrated an association with successful extubation ( p =0.014).  Conclusion. Future studies with larger sample sizes are recommended.  Keywords. Mechanical ventilation, intensive care unit, extubation failure, respiratory muscle strength, peripheral muscle strength, muscle endurance