title: Continuous positive airway pressure versus noninvasive pressure support ventilation to treat atelectasis after cardiac surgery.
abstract: Atelectasis is common after cardiac surgery and may result in impaired gas exchange. Continuous positive airway pressure (CPAP) is often used to prevent or treat postoperative atelectasis. We hypothesized that noninvasive pressure support ventilation (NIPSV) by increasing tidal volume could improve the evolution of atelectasis more than CPAP. One-hundred-fifty patients admitted to our surgical intensive care unit (SICU) with a Radiological Atelectasis Score >or=2 after cardiac surgery were randomly assigned to receive either CPAP or NIPSV four times a day for 30 min. Positive end-expiratory pressure was set at 5 cm H(2)O in both groups. In the NIPSV group, pressure support was set to provide a tidal volume of 8-10 mL/kg. At SICU discharge, we observed an improvement of the Radiological Atelectasis Score in 60% of the patients with NIPSV versus 40% of those receiving CPAP (P = 0.02). There was no difference in oxygenation (Pao(2)/fraction of inspired oxygen at SICU discharge: 280 +/- 38 in the CPAP group versus 301 +/- 40 in the NIPSV group), pulmonary function tests, or length of stay. Minor complications, such as gastric distensions, were similar in the two groups. NIPSV was superior to CPAP regarding the improvement of atelectasis based on radiological score but did not confer any additional clinical benefit, raising the question of its usefulness for altering outcome.
authors.affiliation: *Respiratory Therapy Unit of the Division of Surgical Intensive Care, †Division of Surgical Intensive Care, Department of Anaesthesiology, Pharmacology and Surgical Intensive Care, Geneva University Hospital, Geneva, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Pasquina
authors.forename: Paolo
authors.initials: P
authors.lastname: Merlani
authors.forename: Jean Max
authors.initials: JM
authors.lastname: Granier
authors.forename: Bara
authors.initials: B
authors.lastname: Ricou
mesh_terms: D000368:Aged; D001784:Blood Gas Analysis; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000628:therapy*; D011446:Prospective Studies; D001261:Pulmonary Atelectasis / Q000000981:diagnostic imaging / Q000628:therapy*; D011859:Radiography; D016037:Single-Blind Method; D016896:Treatment Outcome; D014797:Vital Capacity