Circulatory responses to nasotracheal intubation: comparison of GlideScope videolaryngoscope and Macintosh direct laryngoscope.
BACKGROUND
The GlideScope videolaryngoscope (GSVL) has been shown to have no special advantage over the Macintosh direct laryngoscope (MDL) in attenuating the circulatory responses to orotracheal intubation, but no study has compared the circulatory responses to nasotracheal intubation (NTI) using the two devices. This prospective randomized clinical study was designed to determine whether there was a clinically relevant difference between the circulatory responses to NTI with the GSVL and the MDL.


METHODS
Seventy-six adult patients were randomly allocated equally to the GSVL group and the MDL group. After induction of anesthesia, NTI was performed. Non-invasive blood pressure (BP) and heart rate (HR) were recorded before induction (baseline values) and immediately before intubation (post-induction values), at intubation and every minute for a further five minutes. During the observation, times required to reach the maximum values of systolic BP (SBP) and HR, times required for recovery of SBP and HR to postinduction values and incidence of SBP and HR percent changes > 30% of baseline values were also noted. The product of HR and systolic BP, i.e. rate pressure product (RPP), and the areas under SBP and HR vs. time curves (AUC(SBP) and AUC(HR)) were calculated.


RESULTS
The NTI with the GSVL resulted in significant increases in BP, HR and RPP compared to postinduction values, but these circulatory changes did not exceed baseline values. BPs at all measuring points, AUC(SBP), maximum values of BP and incidence of SBP percent increase > 30% of baseline value during the observation did not differ significantly between groups. However, HR and RPP at intubation and their maximum values, AUC(HR) and incidence of HR percent increase > 30% of baseline value were significantly higher in the MDL group than in the GSVL group. Times required for recovery of SBP and HR to postinduction values were significantly longer in the MDL group than in the GSVL group.


CONCLUSIONS
The pressor response to NTI with the GSVL and the MDL was similar, but the tachycardiac response to NTI was lesser and of a shorter duration when using a GSVL than when using an MDL.
Xue
Fu-shan
FS
Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100144, China. fruitxue@yahoo.com.cn
Li
Xuan-ying
XY
Liu
Qian-jin
QJ
Liu
He-ping
HP
Yang
Quan-yong
QY
Xu
Ya-chao
YC
Liao
Xu
X
Liu
Yi
Y
D000328:Adult; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation* / Q000379:methods; D020704:Laryngoscopes; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D014741:Video Recording / Q000295:instrumentation* / Q000379:methods