Simple radiology case. Just something I throw out there as I try to start writing case studies

54 yowm who has undergone CABG 3 vessel. 48 hours later he is on 50% bipap. You are consulted at 2am by an intern, who hopes you can help him so he can avoid looking dumb by calling the attending without a diagnosis. VS wnl except o2sat 95. He shows you this CXR ImageUploadedByTapatalk1406246796.045569.jpg

Questions? Diagnosis?