Reliability of Respiratory System Compliance Calculation during Assisted Mechanical Ventilation: A Retrospective Study

OBJECTIVES: To compare respiratory system compliance (Crs) calculation during controlled mechanical ventilation (MV) and, subsequently, during assisted MV. DESIGN: This is a single-center, retrospective, observational study. SETTING: This study was conducted on patients admitted to Neuro-ICU of Niguarda Hospital (tertiary referral hospital). PATIENTS: We analyzed every patient greater than or equal to 18 years old having a Crsmeasurement in controlled and in assisted MV within 60 minutes. Plateau pressure (Pplat) was considered reliable if it was deemed visually stable for at least 2 seconds. Interventions: Inspiratory pause was incorporated to detect Pplatin controlled and assisted MV. Calculation of Crsand driving pressure were achieved. MEASUREMENTS AND MAIN RESULTS: A total of 101 patients were studied. An acceptable agreement was found (Bland-Altman plot bias-3.9, level of agreement upper 21.6, lower-29.6). Crsin assisted MV was 64.1 (52.6-79.3) and in controlled MV it was 61.2 (50-71.2) mL/cm H2o (p = 0.006). No statistical difference was found in Crs(assisted vs controlled MV) when peak pressure was lower than Pplatnor when peak pressure was higher than Pplat. CONCLUSIONS: A Pplatvisually stable for at least 2 seconds leads to reliable Crscalculation during assisted MV.