Nasal Continuous Positive Airway Pressure May Reduce Pulmonary Morbidity After Cardiac Surgery

Nasal continuous positive airway pressure (nCPAP) may reduce pulmonary morbidity after cardiac surgery, according to the results of a prospective, randomized controlled trial reported in the May issue of Chest.

"Continuous positive airway pressure is a noninvasive respiratory support technique that may prevent pulmonary complications following cardiac surgery," write Alexander Zarbock, MD, from University of Muenster in Muenster, Germany, and colleagues. "This study was conducted to determine the efficacy of prophylactic...nCPAP compared with standard treatment."

After extubation either in the operating room or in the intensive care unit (ICU), 500 patients scheduled for elective cardiac surgery were prospectively randomly assigned to standard treatment including 10 minutes of intermittent nCPAP at 10-cm H₂O every 4 hours or to prophylactic nCPAP at an airway pressure of 10-cm H₂O for at least 6 hours. The main outcome measures were pulmonary complications, including hypoxemia, defined as PaO₂/fraction of inspired oxygen (FIO₂) of less than 100; pneumonia; and reintubation. The secondary outcome measure was the rate of readmission to the ICU or intermediate care unit (IMCU).

Patients receiving prophylactic nCPAP had significantly better arterial oxygenation (PaO₂/FIO₂) without significant effects on heart rate or mean arterial blood pressure. Compared with control subjects, patients receiving prophylactic nCPAP also had lower rates of pulmonary adverse effects of hypoxemia, pneumonia, and reintubation (12/232 patients vs 25/236 patients; P = .03). Patients receiving nCPAP also had a significantly lower readmission rate to the ICU or IMCU vs control subjects (7/232 patients vs 14/236 patients; P = .03).

"The long-term administration of prophylactic nCPAP following cardiac surgery improved arterial oxygenation, reduced the incidence of pulmonary complications including pneumonia and reintubation rate, and reduced readmission rate to the ICU or IMCU," the study authors write. "Thus noninvasive respiratory support with nCPAP is a useful tool to reduce pulmonary morbidity following elective cardiac surgery."

One limitation of this study was exclusion of patients with concomitant pulmonary diseases. The authors also acknowledge that the study was not designed to compare the efficacy of noninvasive ventilation vs nCPAP in the prevention of postoperative atelectasis.

"nCPAP does not require sophisticated technical equipment, and it is easy to apply and quite inexpensive," the study authors conclude. "Therefore, nCPAP can be recommended as a useful tool to prevent postoperative pulmonary complications in patients recovering from cardiac surgery."