Haemodynamic characteristics of COVID‐19 patients with acute respiratory distress syndrome requiring mechanical ventilation. An invasive assessment using right heart catheterization

Caravita, Sergio; Baratto, Claudia; Di Marco, Fabiano; Calabrese, Alice; Balestrieri, Giulio; Russo, Filippo; Faini, Andrea; Soranna, Davide; Perego, Giovanni Battista; Badano, Luigi P.; Grazioli, Lorenzo; Lorini, Ferdinando Luca; Parati, Gianfranco; Senni, Michele

AIMS: Interstitial pneumonia due to coronavirus disease 2019 (COVID‐19) is often complicated by severe respiratory failure. In addition to reduced lung compliance and ventilation/perfusion mismatch, a blunted hypoxic pulmonary vasoconstriction has been hypothesized, that could explain part of the peculiar pathophysiology of the COVID‐19 cardiorespiratory syndrome. However, no invasive haemodynamic characterization of COVID‐19 patients has been reported so far. METHODS AND RESULTS: Twenty‐one mechanically‐ventilated COVID‐19 patients underwent right heart catheterization. Their data were compared both with those obtained from non‐mechanically ventilated paired control subjects matched for age, sex and body mass index, and with pooled data of 1937 patients with ‘typical’ acute respiratory distress syndrome (ARDS) from a systematic literature review. Cardiac index was higher in COVID‐19 patients than in controls [3.8 (2.7–4.5) vs. 2.4 (2.1–2.8) L/min/m(2), P < 0.001], but slightly lower than in ARDS patients (P = 0.024). Intrapulmonary shunt and lung compliance were inversely related in COVID‐19 patients (r = −0.57, P = 0.011) and did not differ from ARDS patients. Despite this, pulmonary vascular resistance of COVID‐19 patients was normal, similar to that of control subjects [1.6 (1.1–2.5) vs. 1.6 (0.9–2.0) WU, P = 0.343], and lower than reported in ARDS patients (P < 0.01). Pulmonary hypertension was present in 76% of COVID‐19 patients and in 19% of control subjects (P < 0.001), and it was always post‐capillary. Pulmonary artery wedge pressure was higher in COVID‐19 than in ARDS patients, and inversely related to lung compliance (r = −0.46, P = 0.038). CONCLUSIONS: The haemodynamic profile of COVID‐19 patients needing mechanical ventilation is characterized by combined cardiopulmonary alterations. Low pulmonary vascular resistance, coherent with a blunted hypoxic vasoconstriction, is associated with high cardiac output and post‐capillary pulmonary hypertension, that could eventually contribute to lung stiffness and promote a vicious circle between the lung and the heart.