Objectives: To assess the efficacy of noninvasive positive pressure ventilation (NPPV) in improving hypoxemia after extubation for Stanford type-A aortic dissection and to compare NPPV using a mask or a helmet. Design: Prospective, interventional study. Setting: Department of Cardiac Surgery of the Beijing Anzhen Hospital, a tertiary university hospital. Participants: Patients experiencing hypoxemia within 24 hours after extubation for Stanford type-A aortic dissection. Interventions: The patients were divided into the following 3 groups: high-flux inhalation of oxygen with a Venturi mask (control patients), NPPV with a mask (mask group), and NPPV with a helmet (helmet group) (n = 25/group). Measurements and Main Results: Data for blood gas analysis, vital signs, heart function, and complications were collected before the treatment, after 1 and 6 hours of treatment, and at the end of treatment. The oxygen partial pressure/fraction of inspired oxygenation index or PaO2/FlO(2) ratio and the oxygen partial pressure were higher and carbon dioxide partial pressure was lower in the mask and helmet groups compared with that of control patients. Compared with control patients and the mask group, the helmet group showed a slower heart rate, lower average arterial pressure, and improved left ventricular ejection fraction, leading to a lower incidence of reintubation and a shorter hospital stay. Conclusions: NPPV with a helmet may quickly improve oxygen partial pressure, decrease carbon dioxide partial pressure, decrease the reintubation rate, and effectively shorten the hospital stay after extubation for Stanford type-A aortic dissection. (C) 2016 Elsevier Inc. All rights reserved.