Esophageal and transdiaphragmatic pressure swings as indices of inspiratory effort.

Abstract Aim To describe the correlation between the inspiratory esophageal and transdiaphragmatic pressure swings (ΔPes and ΔPdi), easily measured indices of inspiratory effort, with the gold-standard, the transdiaphragmatic pressure time product (PTPPdi/min), and assess the accuracy of swing pressures to predict very high or low effort. Method Retrospective analysis of data from patients enrolled in four previous studies. ROC curves of ΔPes and ΔPdi values for specific PTPPdi/min thresholds (50, 150, 200cmH2O·sec/min) were constructed, and the diagnostic accuracy of different thresholds of swing values were computed. Results A threshold of inspiratory ΔP 14-18cmH2O can be used to identify patients with very high inspiratory effort (PTPPdi/min> 200 cmH2O·sec/min). Conclusions The results of this study can help clinicians better select and interpret thresholds of ΔP to evaluate inspiratory effort.