A pilot study to investigate any relationship between sustained maximal inspiratory pressure and extubation outcome

OBJECTIVE: To establish whether any relationship exists between extubation outcome and sustained maximal inspiratory pressures (SMIP). DESIGN AND SETTING: Prospective clinical stud's ill the 7-bed general intensive care unit of a University hospital. SUBJECTS: Twenty-seven intubated adults who were deemed ready for extubation were enrolled. MEASUREMENTS: Standard respiratory parameters and inspiratory muscle function data (ie, SMIP and peak maximal inspiratory pressures [MIP]) were recorded before extubation. RESULTS: SMIP was found to be significantly greater in those who were successfully extubated than in those who underwent a failed extubation (P < .01). Receiver operating characteristic Curves for SMIP data indicated that a cutoff point of 57.5 pressure time units would give a sensitivity and specificity of 1.0 for extubation outcome prediction. Peak MIP was also significantly greater in those successfully extubated (P = .04); a cutoff point of 17.5 cm H2O gave a sensitivity of 1.0 and a specificity of 0.5. CONCLUSIONS: in this study, peak MIP was not specific enough to be clinically useful as a predictor of extubation outcome. SMIP was associated with extubation outcome with equally high sensitivity and specificity and may therefore have a role in outcome prediction.