Temporal change, reproducibility, and interobserver variability in pressure-volume curves in adults with acute lung injury and acute respiratory distress syndrome

Abstract

The static pressure-volume curve of the respiratory system is reasonably reproducible, thus avoiding the need for multiple measurements at a single time. We found excellent interobserver and intraobserver correlation in manual identification of the LIP and UIP. Both LIP and UIP show appreciable daily variability in patients with ALI/ARDS. The multiple occlusion and syringe techniques generate similar values for LIP and UIP.

Measurement of Alveolar Recruitment at the Bedside: The Beginning of a New Era in Respiratory Monitoring?

“…It has been shown that PV curves obtained in static conditions (gross syringe or end-inspiratory occlusion methods) are equivalent to PV curves obtained in quasi-static conditions (constant flows of 3 or 9 L/min), 10 with a high reproducibility. 11 Before starting the automatic measurement of PEEP-induced alveolar recruitment, the clinician has to select the different PEEP levels (a maximum of 5), the constant flow rate (between 1 and 10 L/ min), the maximum inflation pressure (up to 60 cm H 2 O), the maximum volume administration during each PV curve, and the time passed at the highest PEEP to optimize initial lung recruitment. The ventilator performs a descending PEEP trial, because there is evidence that it optimizes PEEP-induced alveolar recruitment.…”

Targeting Inflammation to Prevent Bronchopulmonary Dysplasia: Can New Insights Be Translated Into Therapies?

“…166 Using appropriate lungopening pressure with an adequate lower inflection point in newborn piglets exposed to mechanical ventilation reduces the influx of activated leukocytes into the lungs. 167 However, finding the appropriate opening pressures in adult humans is tricky 168 and is impractical in neonates because it requires paralysis. This may explain why use of an "appropriate PEEP" was never implemented clinically or tested in trials despite observed benefits in infants.…”

Automated measurement of the lower inflection point in a pediatric lung model*

“…This bench study does differ appreciably from the usual pathophysiology seen in acute lung injury and ARDS, in that the model used a standardized and consistent two compartment pediatric lung model for estimating Pflex that does not necessarily reflect the frequently changing lung mechanics that occur daily or even hourly in critically ill patients (32). In patients with lung injury, time constants and opening pressures vary in a nonhomogenous fashion within a single lung unit depending on alterations of therapeutic interventions and disease progression.…”