Role of Integrated Pulmonary Index in Identifying Extubation Failure

The integrated pulmonary index (IPI) utilizes an algorithm based on the measurement of end-tidal carbon dioxide, breathing frequency, heart rate, and oxygen saturation to provide an assessment of the patient's ventilatory status. This clinical trial was designed to determine whether lower IPI values were associated with extubation failure.

This prospective observational trial was conducted in an academic medical center. After institutional review board approval, 100 mechanically ventilated subjects were enrolled. A stand-alone respiratory monitor that measures IPI was placed on subjects before starting a spontaneous breathing trial and continued for up to 48 h postextubation. Clinicians were blinded, and data were recorded continuously. Extubation failure was defined as the need for positive-pressure ventilation within 48 h after extubation. Mixed-effects regression models were employed to examine differences in IPI patterns between subjects with extubation success or failure. Significant IPI changes from baseline were then evaluated to predict extubation outcome.

IPI was successfully recorded on 62 subjects (48 successful and 14 failed extubations). Although mean IPI 5 min before and after extubation were not significantly different, mean IPI 1 h after extubation in the failure group was significantly lower by 1.19 (P = .044) compared with the successful group. Negative change in IPI 1 h after extubation increased odds of failure (odds ratio = 1.57, 95% CI 1.001-2.454). The last mean IPI recorded after extubation was also significantly lower in the failure group compared with the successful group by 3.03 (P < .001). Negative change in the last measured IPI increased odds of failure (odds ratio = 1.72, 95% CI 1.26-2.34).

Declining IPI measurements postextubation are predictive of extubation failure. Further clinical trials are needed to assess the role of IPI in guiding interventions in extubated patients.