Postoperative acute respiratory failure in cardiac surgery.

Objective: To evaluate incidence, causes and outcomes of acute respiratory failure (ARF) in patients after cardiac and aortic surgery.

Material And Methods: A retrospective trial included 3972 patients after elective cardiovascular procedures for the period 2013-2017. Inclusion criterion: sustained reduction of pulmonary function (PaO/FiO<300 mm Hg) in the postoperative period required mechanical ventilation or non-invasive positive pressure mask ventilation for at least 24 h.

Results: ARF developed in 138 (3.5%) cases. It was observed after aortic surgery as a rule (11.2%). Other operations were followed by ARF in 1-3.5% of cases. Incidence of ARF was less after off-pump coronary artery bypass surgery compared with on-pump interventions (1.6 vs. 3.5%, p=0.0469). Acute respiratory distress syndrome was the main reason of ARF (n=37, 26.8%). ARF as a consequence of neurological complications were observed in 25 (18.1%) patients. Exacerbation of COPD and bronchial asthma occurred in 23 (16.1%) patients, paresis of the diaphragm - in 15 (11.7%). In 15 (10.8%) patients, ARF was caused by pneumonia, in 12 (8.7%) cases - pulmonary congestion, in 10 (7.2%) patients - lung injury and haemothorax. Overall ARDS-associated mortality was 21.6%; 15.1% of patients with mild and moderate ARDS died. Severe ARDS was followed by unfavorable outcome in 75% of patients. Nosocomial pneumonia was found in 40.6%, there were no fatal outcomes from this complication.

Conclusion: Acute respiratory failure developed in 3.5% of cardiac patients and was common thoracic and thoracoabdominal aortic surgery. The leading cause of mortality was ARDS (mortality rate 15.1% in mild and moderate syndrome, 75% in severe course of ARDS). Nosocomial pneumonia was diagnosed in 1.4% of patients and was not fatal.