title: Difficult Tracheal Intubation in Obese Gastric Bypass patients.
abstract: Endotracheal intubation is commonly perceived to be more difficult in obese patients than in lean patients. Primarily, we investigated the association between difficult tracheal intubation (DTI) and obesity, and secondarily, the association between DTI and validated scoring systems used to assess the airways, the association between DTI and quantities of anesthetics used to induce general anesthesia, and the association between DTI and difficulties with venous and arterial cannulation.
  
  
  
  This is a monocentric prospective observational clinical study of a consecutive series of 539 obese patients undergoing gastric bypass. Tracheal intubation was done preoperatively together with scoring of Intubation Score (IS), Mallampati (MLP), and Cormack-Lehane classification (CLC) and registration of the quantities of anesthetics and total attempts on cannulation.
  
  
  
  The overall proportion of patients with DTI was 3.5 % and the patients with DTI were more frequently males, had higher CLC, higher American Society of Anesthesiologists physical status classification (ASA), and noticeably, a lower BMI compared to the patients with easy tracheal intubation. After adjustment with multivariable analyses body mass index (BMI) <40, CLC >2, ASA scores >2, and male gender were risk factors of DTI. Males generally had higher CLC, MLP, and ASA scores compared to females, but no difference in BMI. There was no difference in quantities of anesthetics used between the two groups with or without DTI. Intra-venous and intra-arterial cannulation was succeeded in first attempt in 85 and 86 % of the patients, respectively, and there were no association between BMI and difficult vascular access.
  
  
  
  We found no association between increasing BMI and DTI.
authors.affiliation: Department of Surgery, Herlev University Hospital, Herlev Ringvej 75, Herlev, 2730, Denmark. niclas.dohrn@gmail.com.
authors.forename: Niclas
authors.initials: N
authors.lastname: Dohrn
authors.affiliation: Department of Surgery, University Hospital of Aarhus, Nørrebrogade 44, Aarhus, 8000, Denmark.
authors.forename: Thorbjørn
authors.initials: T
authors.lastname: Sommer
authors.affiliation: Department of Anesthesiology and Intensive Care, Lillebaelt Hospital, Skovvangen 2-8, Kolding, 6000, Denmark.
authors.forename: Jannie
authors.initials: J
authors.lastname: Bisgaard
authors.affiliation: Bariatric Center, Mølholm Private Hospital, Brummersvej 1, Vejle, 7100, Denmark.
authors.forename: Ebbe
authors.initials: E
authors.lastname: Rønholm
authors.affiliation: Bariatric Center, Mølholm Private Hospital, Brummersvej 1, Vejle, 7100, Denmark.
authors.forename: Jens Fromholt
authors.initials: JF
authors.lastname: Larsen
mesh_terms: D000768:Anesthesia, General; D015992:Body Mass Index; D005260:Female; D015390:Gastric Bypass; D006305:Health Status Indicators; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects; D007828:Laryngoscopy; D008297:Male; D009765:Obesity / Q000150:complications / Q000601:surgery*; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors
keywords: Airway assessment; Airway management; Difficult tracheal intubation; Gastric bypass; Obesity