Inspiratory pressure/maximal inspiratory pressure: Does it predict successful extubation in critically ill infants and children?

Objective: To evaluate the accuracy of the initial negative inspiratory pressure (PI) to maximal negative inspiratory pressure (PI(max)) ratio in predicting extubation outcome for intubated infants and children. Design: A prospective study. Setting. Pediatric intensive care unit. Patients: A sample of 50 stable intubated pediatric patients who were judged clinically ready for extubation. Methods: Using a one-way valve, PI and PI(max) were measured in all patients, after which the ≤ ratio PI/PI(max) was calculated and its accuracy in predicting extubation outcome evaluated. Measurements and results. A total of 39 patients (78%) were successfully extubated and 11 patients (22%) were not. The mean PI/PI(max) ratio was not significantly different between extubation successes (0.36 ± 0.14) and failures (0.45 ± 0.1) (P > 0.05). The cut-off value of 0.3 for PI/PI(max) identified in adult patients did not discriminate between extubation success and failure in children. Furthermore, a discriminatory cut-off value other than 0.3 could not be identified for infants and children. Conclusion: The PI/PI(max) ratio cannot be used to predict extubation outcome in pediatric patients. Indices that predict extubation outcome in adults should not be extrapolated to infants and children before testing and validation.