Acute cor pulmonale in acute respiratory distress syndrome submitted to protective ventilation: Incidence, clinical implications, and prognosis

Context., The incidence of acute cor pulmonale (ACP), a frequent and usuall y lethal complication of acute respiratory distress syndrome (ARDS) during traditional respiratory support, has never been re-evaluated since protecti ve ventilation gained acceptance. Objective: We performed a longitudinal transesophageal echocardiographic (T EE) study to determine whether this incidence, and its severe implications for prognosis, might have changed in our unit as we altered respiratory str ategy. Design: Prospective open clinical study. Setting. Medical intensive care unit of a university hospital. Patients: Seventy-five consecutive ARDS patients given respiratory support with airway pressure limitation (plateau pressure less than or equal to 30 cm H2O). Interventions: ACP was defined as a ratio of right ventricular end-diastoli c area to left ventricular end-diastolic area in the long axis >0.6 associa ted with septal dyskinesia in the short axis during TEE examination. Results: Normal right ventricular function was present in 56 patients, wher eas right ventricular dysfunction was observed in 19 patients after 2 days of respiratory support. ACP was associated with pulmonary artery hypertensi on, increased heart rate, and decreased stroke index. Significant impairmen t of left ventricular diastolic function was also seen. All echo-Doppler ab normalities were reversible in patients who recovered, and the mortality ra te was the same in both groups (32%). However, ACP patients who recovered r equired a longer period of respiratory support. A multivariate analysis ind ividualized Paco2 level as the sole factor independently associated with AC P, suggesting that ACP development in ARDS is influenced by the severity of lung damage and/or the respiratory strategy. Conclusion: Evaluation of right ventricular function by TEE in a group of 7 5 ARDS patients submitted to protective ventilation revealed the persistenc e of a 25% incidence of ACP, resulting in detrimental hemodynamic consequen ces associated with tachycardia. However, ACP was reversible in patients wh o recovered and did not increase mortality.