title: Prevention of Unilateral Pulmonary Edema Complicating Robotic Mitral Valve Operations.
abstract: BACKGROUND
  Unilateral pulmonary edema (UPE) has been reported after mitral operations performed through the right side of the chest. The clinical presentation is compatible with an ischemia-reperfusion injury. This report describes modifications to robotic mitral valve operations that were designed to reduce UPE.
  
  
  METHODS
  We reviewed 15 patients with UPE after robotic mitral valve operations from 2006 through 2012. Technique modifications to reduce right lung ischemia were used from 2013 through June 2015. Modifications included alterations in patient position, ventilation, and perfusion factors. The incidence of UPE before and after modifications was determined, as was perfusion factors and outcomes in a higher-risk patient subgroup with pulmonary hypertension and prolonged bypass procedures.
  
  
  RESULTS
  The incidence of UPE was 1.4% (n = 15) in 1,059 consecutive robotic mitral valve procedures using the standard technique and 0.0% in 435 consecutive procedures using the modified technique (p < 0.02). All patients with UPE had pulmonary hypertension and bypass times of greater than 120 minutes. Patients in the higher-risk subgroup had significantly lower systemic temperature (31°C [range, 30°-32°C] versus 34°C [range, 33°-34°C]; p < 0.01) and higher mean perfusion pressure (67mm Hg [range 62-72 mm Hg] versus 54 mm Hg [range, 52-57 mm Hg]; p < 0.01) on bypass using the modified technique. The incidence of UPE in higher-risk patients was significantly reduced using the modified technique (0% versus 5.6%; p < 0.01) without any increase in overall morbidity or mortality.
  
  
  CONCLUSIONS
  The incidence of UPE in patients undergoing robotic mitral valve operations has been significantly reduced using a modified technique, without increasing the perioperative complication rate. Further work is necessary to validate this protocol and understand the pathophysiology of postoperative UPE.
authors.affiliation: Division of Cardiac Surgery, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Moss
authors.affiliation: Division of Cardiothoracic Surgery, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Halkos
authors.affiliation: Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia.
authors.forename: Jose N
authors.initials: JN
authors.lastname: Binongo
authors.affiliation: Division of Cardiothoracic Surgery, Emory University School of Medicine, Atlanta, Georgia. Electronic address: douglas.murphy@emory.edu.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Murphy
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000175:diagnosis / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D011654:Pulmonary Edema / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D012189:Retrospective Studies; D012371:Robotics; D014481:United States / Q000453:epidemiology