TY - JOUR T1 - Expiratory Pause Maneuver to Assess Inspiratory Muscle Pressure During Assisted Mechanical Ventilation: A Bench Study JF - Respiratory Care SP - 1649 LP - 1656 DO - 10.4187/respcare.09047 VL - 66 IS - 11 AU - Richard H Kallet AU - Justin S Phillips AU - Travis J Summers AU - Gregory Burns AU - Lance Pangilinan AU - Logan Carothers AU - Earl R Mangalindan AU - Michael S Lipnick Y1 - 2021/11/01 UR - http://rc.rcjournal.com/content/66/11/1649.abstract N2 - BACKGROUND: The generation of excessive inspiratory muscle pressure (Pmus) during assisted mechanical ventilation in patients with respiratory failure may result in acute respiratory muscle injury and/or fatigue, and exacerbate ventilator-induced lung injury. A readily available noninvasive surrogate measure of Pmus may help in titrating both mechanical ventilation and sedation to minimize these risks. This bench study explored the feasibility and accuracy of using a ventilator’s expiratory pause hold function to measure Pmus across multiple operators.METHODS: A standardized technique for executing a brief (<1 s) expiratory pause maneuver was used to measure the airway occlusion pressure change (Δ Paw) by using 3 simulated Pmus (Δ Pmus: 5, 10, 15 cm H2O) under (1) pressure support ventilation (0, 10, 15 cm H2O), (2) volume and pressure-regulated volume ventilation, (3) flow and pressure-triggering, and (4) varying levels of PEEP and pressure-rise time. Individual and grouped measurements were made by 4–7 clinicians on 3 different ventilators. The concordance between occlusion Δ Paw and Δ Pmus was arbitrarily set at ≤ 2 cm H2O. Data were evaluated by using analysis of variance and the Tukey-Kramer posttest. Correlation was assessed by using the Pearson R test; bias and precision were assessed by using the Bland-Altman method. Alpha was set at 0.05.RESULTS: Grouped expiratory pause maneuver measurements of occlusion Δ Paw across simulated Δ Pmus, mode and level of ventilatory support showed reasonable concordance, regardless of the ventilator used. Occlusion Δ Paw accuracy frequently decreased by ∼3 cm H2O when both pressure support ventilation and Δ Pmus reached 15 cm H2O. Expiratory pause maneuver accuracy was not affected by trigger mechanism and/or sensitivity, PEEP, or the post-trigger pressurization rate. In general, only small differences in Δ Paw occurred among the individual operators.CONCLUSIONS: The expiratory pause maneuver generally provided reproducible, stable approximations of Δ Pmus across ventilators and ventilator settings, and a range of simulated effort. Technique standardization produced relatively consistent results across multiple operators. The expiratory pause maneuver seemed feasible for general use in monitoring inspiratory effort during assisted mechanical ventilation. ER -