Thus it is possible that sedation and mode of ventilation limited training efficacy. In a later study, deeper
levels of sedation were associated with a decrease in maximal inspiratory pressure during mechanical ventilation (Caruso et al 2008). The mode of inspiratory muscle training also differed between studies and included check details threshold pressure training and adjustment of ventilator trigger sensitivity. It has been suggested that with adjustment of the ventilator trigger sensitivity, maximal inspiratory pressure may not be maintained as resistance is only offered initially when the valve opens (Cader et al 2010). These authors suggest that threshold pressure training instead provides resistance for a longer duration and thus may be more effective for inspiratory muscle training. Studies in our review also used differing training regimes with the starting pressures and loads ranging from 20% of maximal inspiratory pressure (Caruso et al 2005) to the highest pressure tolerated (Martin et al 2011). Differences in the progression of duration and load were also seen throughout the three studies in this review. In recent systematic
reviews of inspiratory muscle training in chronic BYL719 in vivo obstructive pulmonary disease (Gosselink et al 2011, Geddes et al 2008), 30% of maximal inspiratory pressure is recommended as the minimal initial training pressure required to increase inspiratory muscle strength. In intensive care patients, the level of maximal inspiratory pressure required to provide
an adequate training stimulus is currently unknown. Physiotherapists, with their knowledge of exercise prescription in the intensive care environment, are ideally placed to pursue further research in this area and – should inspiratory muscle training be shown to be effective – to prescribe and supervise inspiratory muscle training in selected patients who are receiving mechanical ventilation. Inspiratory muscle training in the form of threshold PAK6 pressure training is low cost, easy for patients to use, and requires little staff training. The training protocols used in the three studies in this review are of relatively short duration, which makes the training a realistic and feasible treatment within the overall rehabilitation of patients in the intensive care unit. In summary, this systematic review has found that inspiratory muscle training (in the form of threshold pressure training and ventilator sensitivity adjustment) significantly increases inspiratory muscle strength with minimal reported adverse effects when used for the purpose of weaning from mechanical ventilation.