title: Hemodynamic responses to tracheal intubation with the Glidescope videolaryngoscope: a comparison of oral and nasal routes.
abstract: BACKGROUND
  Although there have been numerous favorable reports on the uses of the GlideScope videolaryngoscope (GSVL) in oral and nasal intubations, no study has compared the hemodynamic responses to oral and nasal intubations with the GSVL in a single clinical trial. The purpose of this randomized clinical study was to determine whether there was a clinically relevant difference between the hemodynamic responses to oral and nasal intubations with the GSVL.
  
  
  METHODS
  A total of 71 patients, ASA physical status I, aged 18-50 years, scheduled for elective plastic surgery under general anesthesia, were randomly allocated to the oral intubation group (OI group) and the nasal intubation group (NI group). Noninvasive blood pressure (BP) and heart rate (HR) were recorded before (baseline values) and after anesthesia induction (postinduction values), at intubation and every minute for a further 5 minutes. Maximum values of BP and HR during the observation were noted. The product of HR and systolic blood pressure (rate pressure product, RPP), the percent changes of systolic blood pressure (SBP) and HR relative to the baseline values at every measuring point, and the areas under the SBP and HR versus time curves were calculated.
  
  
  RESULTS
  The intubation time was significantly longer in the NI group than in the OI group. The total incidence of difficulties encountered during laryngoscopy and intubation were higher in the OI group than in the NI group (29% vs. 6%, p < 0.05). BP at all measuring points, the maximum values of BP, the area under the SBP versus time curve, and the incidence of SBP percent increase more than 30% of baseline value did not differ significantly between the two groups. However, HR and RPP at intubation and their maximum values during the observation, the area under the HR versus time curve, and the incidence of HR percent increase more than 30% of baseline value were significantly higher in the OI group than in the NI group (p < 0.05). As compared with the NI group, the times required to reach the maximum values of SBP and HR were significantly shorter and the times required for recovery of SBP and HR to postinduction values were significantly longer in the OI group (p < 0.05).
  
  
  CONCLUSIONS
  In anesthetized adult patients, oral and nasal intubations with the GSVL can result in a similar pressor response. However, the tachycardic response to nasal intubation using a GSVL is smaller and of shorter duration than that to oral intubation using a GSVL.
authors.affiliation: Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 33 Ba-Da-Chu Road, Shi-Jing-Shan, Beijing, China. fruitxue@yahoo.com.cn
authors.forename: Fu-Shan
authors.initials: FS
authors.lastname: Xue
authors.forename: Ya-Chao
authors.initials: YC
authors.lastname: Xu
authors.forename: Qian-Jin
authors.initials: QJ
authors.lastname: Liu
authors.forename: Quan-Yong
authors.initials: QY
authors.lastname: Yang
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Xu
authors.initials: X
authors.lastname: Liao
authors.forename: Xuan-Ying
authors.initials: XY
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D020704:Laryngoscopes; D008297:Male; D008875:Middle Aged; D012032:Refractory Period, Electrophysiological; D014741:Video Recording