Alteration of Lung Physiology with the Administration of Convalescent Plasma in ARDS Patients Intubated with COVID-19 Pneumonia

Abstract

Background: It remains unknown to what degree lung physiology is altered by administration of convalescent plasma in patients intubated with ARDS due to COVID-19 pneumonia. Although no longer clinically used as treatment for COVID-19, convalescent plasma therapy could be deployed again should new virus threats emerge in the future. Aim: To evaluate changes in ventilator physiologic variables in response to convalescent plasma transfusion using a retrospective, observational, case control study of intubated patients with COVID-19 pneumonia. Methods: Patients who were receiving mechanical ventilation due to COVID-19 at the time of administration of convalescent plasma therapy (CPT) were matched to control patients who did not receive convalescent plasma. Ventilatory data such as compliance, positive end-expiratory pressure (PEEP), FiO2 administered, PaO2/FiO2 ratio, and tidal volume were collected pre and post administration. Panel-level random-effects linear regression models were used to assess the mean difference and interactions between CPT and cases vs controls over time. Results: 12 patients received CPT while intubated and were matched to 35 intubated control patients who did not receive CPT. In total, 857 separate measurements of static compliance were obtained over time. No significant difference in static compliance was seen after CPT. In cases, adjusted mean static compliance was 30.8 (95% CI (23.3, 38.4))mL/cm H2O before CPT and 28.2 (95% CI (20.7,35.6)) mL/cm H2O afterwards. Controls adjusted mean static compliance was 33.9 (95% CI (29.5, 38.4)) mL/cm H2O before versus 32.2 (95% CI (27.9, 36.5)) mL/cm H2O afterwards. Variables that had small but statistically significant differences pre vs post CPT among cases and controls were systolic and diastolic blood pressure, FiO2, heart rate, applied PEEP, and respiratory rate. Conclusion: While some statistically significant physiologic effects were seen with CPT in mechanically ventilated patients, these were deemed to be small and clinically insignificant. This is consistent with prior research on less acutely ill COVID-19 patients.