title: Hypoxemia during one-lung ventilation for robot-assisted coronary artery bypass graft surgery.
abstract: BACKGROUND
  Robot-assisted coronary artery bypass grafting requires continuous one-lung ventilation (OLV) to evacuate the thoracic cavity. Whether this ventilatory mode subjects patients to serious hypoxemia remains underinvestigated.
  
  
  METHODS
  From 2005 to 2010, all patients receiving robot-assisted coronary artery bypass graft surgery using OLV with active capnothorax for internal mammary artery harvesting and then passive pneumothorax for minithoracotomy direct-vision coronary bypass graft surgery were included. Patients' variables of oxygenation were monitored and compared throughout the whole surgical period. Persistent oxygen desaturation (arterial oxygen pressure <70 mm Hg) refractory to primary managements was defined as a hypoxemic event, and predictors of such events were identified by multivariate regression analysis.
  
  
  RESULTS
  A total of 255 consecutive patients were enrolled. Average oxygen saturation decreased modestly during the first stage of OLV with active capnothorax, causing hypoxemic events in 9 patients (4.3%) leading to death in 2 (0.8%), whereas it dropped drastically in the second stage of OLV with passive pneumothorax, resulting in hypoxemic events in 32 patients (12.6%) and death in 1 (0.4%). Multivariate regression analysis identified high pulmonary vascular resistance and low left ventricular ejection fraction as predictors of hypoxemia during internal mammary artery takedown, whereas prolonged procedure and chronic obstructive pulmonary disease were identified as predictors during minithoracotomy bypass grafting.
  
  
  CONCLUSIONS
  Robot-assisted two-stage coronary artery bypass surgery employing OLV could be complicated by serious hypoxemia especially at the minithoracotomy grafting stage and in patients with specific risk factors. Thus, when managing such patients, invasive monitoring and aggressive treatment of arterial desaturation are mandatory to ensure the patient's safety and procedural smoothness.
authors.affiliation: Department of Anesthesiology and Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Tsun-Jui
authors.initials: TJ
authors.lastname: Liu
authors.forename: Meng-Shen
authors.initials: MS
authors.lastname: Shih
authors.forename: Wen-Lieng
authors.initials: WL
authors.lastname: Lee
authors.forename: Kuo-Yang
authors.initials: KY
authors.lastname: Wang
authors.forename: Chia-Ning
authors.initials: CN
authors.lastname: Liu
authors.forename: Chih-Jen
authors.initials: CJ
authors.lastname: Hung
authors.forename: Hui-Chin
authors.initials: HC
authors.lastname: Lai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001026:Coronary Artery Bypass / Q000379:methods*; D003324:Coronary Artery Disease / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D007431:Intraoperative Complications / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D061810:One-Lung Ventilation / Q000009:adverse effects* / Q000379:methods; D010100:Oxygen / Q000097:blood; D012189:Retrospective Studies; D012307:Risk Factors; D012371:Robotics; D013624:Taiwan / Q000453:epidemiology; D016896:Treatment Outcome
chemical_list: D010100:Oxygen