Esophageal and transdiaphragmatic pressure swings as indices of inspiratory effort

Abstract

AimTo 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 in predicting very high or low effort. MethodRetrospective analysis of data from patients enrolled in four previous studies. ROC curves of ΔPes and ΔPdi values for specific PTPPdi/min thresholds (50, 150, 200 cmH2O × sec/min) were constructed, and the diagnostic accuracy of different thresholds of swing values were computed. ResultsA threshold of inspiratory ΔP<7cmH2O can be used to identify most patients with low effort, as lower ΔP thresholds have low sensitivity. Thresholds of inspiratory ΔP>14–18cmH2O can be used to identify patients with very high inspiratory effort (PTPPdi/min> 200 cmH2O × sec/min). ConclusionsThe results of this study can help clinicians better select and interpret thresholds of ΔP to evaluate inspiratory effort.