title: Laryngoscopy in conscious patients with remifentanil: how useful is an "awake look"?
abstract: OBJECTIVE
  To determine the sensitivity and specificity of direct laryngoscopy in the conscious patient as a diagnostic test for difficult direct laryngoscopy in the unconscious patient.
  
  
  METHODS
  Prospective case series.
  
  
  METHODS
  Various operating rooms in a Canadian tertiary-care hospital.
  
  
  METHODS
  81 ASA physical status 1, 2, and 3 subjects undergoing elective surgery.
  
  
  METHODS
  A bolus of midazolam was given and a continuous infusion of remifentanil was started and adjusted as needed. Direct laryngoscopy was performed in the conscious subject. No topical anesthesia was applied to the upper airway.
  
  
  METHODS
  The modified Cormack-Lehane grade was recorded with each subject conscious and unconscious. Other data collected before the intervention included age, gender, height, weight, body mass index, Mallampati class, thyromental distance, mouth opening, previous history of failed or difficult intubation, history of hypertension or obstructive sleep apnea, and routine use of beta blockers. The time of intravenous placement, total dose and duration of remifentanil infusion, and time of endotracheal tube placement were recorded. The lowest oxygen saturation, lowest and highest systolic blood pressure and heart rate, and presence or absence of gagging, coughing, or chest wall rigidity were also noted. Subjects were also asked to complete a questionnaire in the recovery room regarding recall and the degree of discomfort experienced.
  
  
  RESULTS
  43 of 81 subjects were graded 1 or 2a when the laryngoscopy was done in the conscious subject. Six of the 38 subjects who were graded as a difficult laryngoscopy (grade 2b or higher) when they were conscious also remained a difficult laryngoscopy when unconscious and paralyzed. Sensitivity and specificity of direct laryngoscopy in the conscious subject as a diagnostic test for difficult direct laryngoscopy in the unconscious subject were 100% [95% confidence interval (CI) 0.52 to 1] and 57% (95% CI 0.47 to 0.70), respectively.
  
  
  CONCLUSIONS
  Using remifentanil as the sole analgesic allows evaluation of the larynx with direct laryngoscopy in a conscious patient. A poor Cormack-Lehane grade in a conscious patient may or may not improve with general anesthesia.
authors.affiliation: Department of Anesthesiology, the Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Gupta
authors.forename: Robert
authors.initials: R
authors.lastname: Macneil
authors.forename: Gregory
authors.initials: G
authors.lastname: Bryson
mesh_terms: D000328:Adult; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000627:therapeutic use*; D002170:Canada; D017558:Elective Surgical Procedures / Q000379:methods; D005260:Female; D006801:Humans; D007828:Laryngoscopy / Q000379:methods*; D007830:Larynx; D008297:Male; D008874:Midazolam / Q000008:administration & dosage; D008875:Middle Aged; D010880:Piperidines / Q000008:administration & dosage / Q000627:therapeutic use*; D011446:Prospective Studies; D000077208:Remifentanil; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D014851:Wakefulness
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D008874:Midazolam