Right heart function during acute respiratory distress syndrome

Abstract

Acute respiratory distress syndrome (ARDS) is burdened with significant mortality, mainly in connection with circulatory failure. The right ventricle (RV) is the weak link of hemodynamic stability among ARDS patients and its failure, also named "severe" acute cor pulmonale (ACP), is responsible for excess mortality. Driving pressure ≥18 cmH₂O, PaCO₂ ≥48 mmHg and PaO₂/FiO₂ <150 mmHg are three preventable factors recently identified as independently associated with ACP, on which ventilator strategy designed to protect the RV has to focus. This is largely achieved by the use of early and extended sessions of prone positioning (PP) and by daily monitoring of the RV by echocardiography.

Keywords: Acute respiratory distress syndrome (ARDS); acute cor pulmonale (ACP); driving pressure; hypercapnia; oxygenation; right ventricle (RV).

Figure 1

Times scale representing changes in respiratory strategy and the three main risk-identified factors for acute cor pulmonale in ARDS. Improvement of oxygenation, decrease in driving pressure and correction of hypercapnia during the three main eras of ventilator strategy are materialized by blue lines, while their impact on the incidence of ACP and on mortality is illustrated by the red line. White arrows represent the main therapeutics with an impact on outcome. ARDS, acute respiratory distress syndrome; ACP, acute cor pulmonale; Pplat, plateau pressure; V_T, tidal volume; NO, nitric oxide; dp, driving pressure.