title: Obesity, epidural analgesia, and subcostal incision are risk factors for postoperative desaturation.
abstract: OBJECTIVE
  This study was designed to determine the incidence of oxygen desaturation after upper abdominal surgery during the first 48 hr on general surgical wards and also to identify risk factors for oxygen desaturation.
  
  
  METHODS
  This descriptive study was conducted in 206 patients not expected to receive supplemental oxygen postoperatively who were undergoing upper abdominal surgery in a tertiary care university hospital. Desaturation was classified either as constant, i.e., oxygen saturation < 90% for > three minutes or < 85% once or as episodic, i.e., when oxygen saturation is decreased by > or = 5% below baseline for one to two minutes ten times or more during the night period. Possible risk factors were elderly patients (> 70 yr), obesity (body mass index [BMI] > 25 kg.m(-2)), smoking, surgical time > 180 min, postoperative pain control methods, intraoperative blood loss, and site of incision.
  
  
  RESULTS
  Of the 206 patients enrolled, 171 were retained for analysis. Desaturation occurred in 65 patients (38%). Forty-eight of these had constant hypoxemia with nadir oxygen saturation values ranging from 71-89%. The remaining 17 patients experienced nocturnal episodic hypoxemia. After multivariate analysis, the three factors that correlated with postoperative desaturation were BMI > 25 (adjusted odds ratio [OR] 3.06; 95% confidence interval (CI) 1.38-6.79; P = 0.006), subcostal incision (OR 2.68; 95%CI 1.34-5.38; P = 0.005), and neuraxial opioids (OR 2.44; 95%CI 1.21-4.91; P = 0.013).
  
  
  CONCLUSIONS
  Oxygen desaturation is common after upper abdominal surgery, and the risk factors are obesity, a subcostal incision, and neuraxial opioid administration.
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand. siasru@mahidol.ac.th
authors.forename: Arunotai
authors.initials: A
authors.lastname: Siriussawakul
authors.forename: Sahatsa
authors.initials: S
authors.lastname: Mandee
authors.forename: Jathuporn
authors.initials: J
authors.lastname: Thonsontia
authors.forename: Piyasak
authors.initials: P
authors.lastname: Vitayaburananont
authors.forename: Somsak
authors.initials: S
authors.lastname: Areewatana
authors.forename: Jaruwan
authors.initials: J
authors.lastname: Laonarinthawoot
mesh_terms: D000005:Abdomen / Q000601:surgery; D000328:Adult; D000367:Age Factors; D000368:Aged; D015360:Analgesia, Epidural / Q000009:adverse effects* / Q000379:methods; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects; D016063:Blood Loss, Surgical; D005260:Female; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000150:complications*; D010100:Oxygen / Q000097:blood*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013997:Time Factors
chemical_list: D000701:Analgesics, Opioid; D010100:Oxygen