Estimation of inspiratory effort using airway occlusion maneuvers in ventilated children: a secondary analysis of an ongoing randomized trial testing a lung and diaphragm protective ventilation strategy

Background Monitoring respiratory effort in ventilated patients is important to balance lung and diaphragm protection. Esophageal manometry remains the gold standard for monitoring respiratory effort but is invasive and requires expertise for its measurement and interpretation. Airway pressures during occlusion maneuvers may provide an alternative, although pediatric data are limited. We sought to determine the correlation between change in esophageal pressure during tidal breathing (Delta Pes) and airway pressure measured during three airway occlusion maneuvers: (1) expiratory occlusion pressure (Pocc), (2) airway occlusion pressure (P0.1), and (3) respiratory muscle pressure index (PMI) in children. We also sought to explore pediatric threshold values for these pressures to detect excessive or insufficient respiratory effort. Methods Secondary analysis of physiologic data from children between 1 month and 18 years of age with acute respiratory distress syndrome enrolled in an ongoing randomized clinical trial testing a lung and diaphragm protective ventilation strategy (REDvent, R01HL124666) Delta Pes, Pocc, P0.1, and PMI were measured. Repeated measure correlations were used to investigate correlation coefficients between Delta Pes and the three measures, and linear regression equations were generated to identify potential therapeutic thresholds. Results There were 653 inspiratory and 713 expiratory holds from 97 patients. Pocc had the strongest correlation with Delta Pes (r = 0.68), followed by PMI (r = 0.60) and P0.1 (r = 0.42) Delta Pes could be reliably estimated using the regression equation Delta Pes = 0.66 xPocc (R-2 = 0.82), with Pocc cut-points having high specificity and moderate sensitivity to detect respective Delta Pes thresholds for high and low respiratory effort. There were minimal differences in the relationship between Pocc and Delta Pes based on age (infant, child, adolescent) or mode of ventilation (SIMV versus Pressure Support), although these differences were more apparent with P0.1 and PMI. Conclusions Airway occlusion maneuvers may be appropriate alternatives to esophageal pressure measurement to estimate the inspiratory effort in children, and Pocc represents the most promising target.

Automated summary

The study found that airway pressure measured during occlusion maneuvers can be used to estimate respiratory effort in children, and expiratory occlusion pressure has the strongest correlation with esophageal pressure change.