The effect of inspiratory muscle training was to reduce the weaning period by 1.7 days (95% CI 0.4 to 3.0), as presented in Table 4, with individual data in Table 5 (see eAddenda for Table 5). Prior to the weaning period, the controlled ventilation period (see Table 1) accounted for approximately half of the total ventilation period. A Kaplan-Meier analysis of the total intubation time (ie, the controlled ventilation period plus the weaning period) did not identify a significant difference between the experimental and control groups (p = 0.72, see Figure 2.) Although we screened GW3965 molecular weight 198 patients in the intensive care unit, a large proportion of these critically ill patients

died or were tracheostomised either before or after commencing weaning. This is typical of research in inspiratory muscle training in the intensive care setting (Caruso et al 2005, Chang et al 2005a, How et al 2007, Sprague and Hopkins 2003). This loss to follow-up was one limitation of the study. It was compounded by the wide variability in the condition of these patients, including modifications to their medication regimen, psychological state, haemodynamic stability, and degree of sepsis. Nevertheless,

the sample size remained sufficient for statistically significant between-group differences to be identified selleckchem on several outcomes. Another limitation of the study was the lack of blinding. However, because informed consent was provided by the relatives of these critically ill patients, the potential for placebo and Hawthorne effects to operate within the patients was reduced. Previous research suggests that imbalance between the ventilatory load and the strength and endurance of the respiratory muscles is an important determinant of dependence on mechanical ventilation. For example, patients who have success in weaning have a significantly higher maximal inspiratory pressure than those who do not wean successfully (Epstein et al 2002). This relationship is also reflected in our data, with

the experimental group showing both a significant increase in maximal 17-DMAG (Alvespimycin) HCl inspiratory pressure and a reduction in the weaning period when compared to the control group. Our findings that inspiratory muscle training improved both inspiratory muscle strength and the weaning process are also similar to the findings of several other case series. Martin and colleagues (2002), Sprague and Hopkins (2003), and Chang and colleagues (2005b) delivered inspiratory muscle training to tracheostomised patients with a long-standing dependence on mechanical ventilation. All of these patients showed improved inspiratory muscle strength and almost all weaned successfully within several weeks of starting the training.