Driving Pressure, Elastance, and Outcomes in a Real-World Setting: A Bi-Center Analysis of Electronic Health Record Data

Andrew J Goodwin; Daniel L Brinton; Charles Terry; George Carter; D Clark Files; Katie Kirchoff; Dee W Ford; Annie N Simpson

doi:10.1097/CCE.0000000000000877

Driving Pressure, Elastance, and Outcomes in a Real-World Setting: A Bi-Center Analysis of Electronic Health Record Data

Crit Care Explor. 2023 Feb 24;5(3):e0877. doi: 10.1097/CCE.0000000000000877. eCollection 2023 Mar.

Authors

Andrew J Goodwin¹, Daniel L Brinton², Charles Terry¹, George Carter¹, D Clark Files³, Katie Kirchoff⁴, Dee W Ford¹, Annie N Simpson²

Affiliations

¹ Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, Medical University of South Carolina, Charleston, SC.
² Department of Health Care Leadership and Management, Medical University of South Carolina, Charleston, SC.
³ Section on Pulmonary, Critical Care, Allergy, and Immunologic Disease, Wake Forest University, Winston Salem, NC.
⁴ Biomedical Informatics Center, College of Medicine Medical University of South Carolina, Charleston, SC.

Abstract

Emerging evidence suggests the potential importance of inspiratory driving pressure (DP) and respiratory system elastance (E_RS) on outcomes among patients with the acute respiratory distress syndrome. Their association with outcomes among heterogeneous populations outside of a controlled clinical trial is underexplored. We used electronic health record (EHR) data to characterize the associations of DP and E_RS with clinical outcomes in a real-world heterogenous population.

Design: Observational cohort study.

Setting: Fourteen ICUs in two quaternary academic medical centers.

Patients: Adult patients who received mechanical ventilation for more than 48 hours and less than 30 days.

Interventions: None.

Measurements and main results: EHR data from 4,233 ventilated patients from 2016 to 2018 were extracted, harmonized, and merged. A minority of the analytic cohort (37%) experienced a Pao₂/Fio₂ of less than 300. A time-weighted mean exposure was calculated for ventilatory variables including tidal volume (V_T), plateau pressures (P_PLAT), DP, and E_RS. Lung-protective ventilation adherence was high (94% with V_T < 8.5 mL/kg, time-weighted mean V_T = 6. 8 mL/kg, 88% with P_PLAT ≤ 30 cm H₂O). Although time-weighted mean DP (12.2 cm H₂O) and E_RS (1.9 cm H₂O/[mL/kg]) were modest, 29% and 39% of the cohort experienced a DP greater than 15 cm H₂O or an E_RS greater than 2 cm H₂O/(mL/kg), respectively. Regression modeling with adjustment for relevant covariates determined that exposure to time-weighted mean DP (> 15 cm H₂O) was associated with increased adjusted risk of mortality and reduced adjusted ventilator-free days independent of adherence to lung-protective ventilation. Similarly, exposure to time-weighted mean E_RS greater than 2 cm H₂O/(mL/kg) was associated with increased adjusted risk of mortality.

Conclusions: Elevated DP and E_RS are associated with increased risk of mortality among ventilated patients independent of severity of illness or oxygenation impairment. EHR data can enable assessment of time-weighted ventilator variables and their association with clinical outcomes in a multicenter real-world setting.