Comparison King Vision Video Laryngoscopy 、McGrath MAC Video Laryngoscopy With Macintosh Laryngoscopy for Nasal Intubation
Phase: NA
Conditions: Nasal Intubation
Sponsor: Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University

 
 
 
 
 
 
STUDY PROTOCOL 
Nasal Intubation Using King Vision Video Laryngoscopy 
suny2 
(NCT03126344) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
April 27, 2017 

STUDY PROTOCOL 
Title: A randomized controlled comparison of non-channeled king vision, McGrath MAC video  
laryngoscope and Macintosh direct laryngoscope for nasotracheal intubation in patients with  
predicted difficult intubations.  
  
Background: King Vision and McGrath MAC video laryngoscopes (VLs) are increasingly used.  
However, it remains unclear whether non-channeled King Vision or McGrath MAC VL, compared  
with conventional laryngoscope, provide shorter intubation time and a higher first success rate for  
NTI when used by experienced provider in management of predicted difficult intubation. It is also  
unclear whether non-channeled King Vision VL is superior to McGrath MAC VL when used for  
NTI.  
  
Objective: To evaluate the performance of nasotracheal intubation in patients with predicted  
difficult intubations using non-channeled King Vision VL, McGrath MAC VL or Macintosh  
laryngoscope by experienced intubators.  
  
Study Design: A single blind, three parallel arms, randomized controlled trial comparing NTIs  
using non-channeled King Vision VL, McGrath MAC VL and Macintosh DL in adults with  
predictors of difficult airways.  
  
Subjects: Consecutive patients, between 18 and 60 years old with American Society of  
Anesthesiologists (ASA) classification of I or II, and requiring NTI for elective oral and  
maxillofacial surgery, were screened in the Preoperative Evaluation Unit of our institute.  
  
Sample size: Based on the analysis of power analysis software, we take the type I error α as 0.05,  
the expected effect is 0.8, and the ideal test efficacy level is 0.8, then the minimum sample size of  
each group is 26. In order to reduce the loss of follow-up error, add 20% on this basis, then each  
group needs about 30 cases.  
  
Recruitment method: Inpatients  
  
Inclusion criteria: EGRI score 1–7.   
   
Exclusion criteria: EGRI score > 7, history of reflux or diagnosed oesophageal disease, severe  
obstructive sleep apnea (OSA) and morbid obesity (body mass index > 40 kg/m2)] 
 
Study Methods:   
1. Determine the subjects: select the patients who need nasotracheal intubation for elective  
operation, and determine 90 subjects strictly according to the inclusion and exclusion criteria, 30  
in each group.   
2.Group: Patients were randomly assigned to King Vision group, McGrath group or Macintosh  
group via a computer-generated randomization table: King Vision video laryngoscope group  
(group K, n = 30), McGrath MAC video laryngoscope group (group M1, n = 30) and Macintosh  
laryngoscope group (group M2, n = 30).   

3.Anesthetic methods: the anesthetic methods of three groups were the same. Patients were asked  
which nostril was clearer. If both sides were equal and the surgeon had no objection, the right  
nostril was chosen.   
No premedication was administered. Lactated Ringer’s solution infusion was started intravenously  
to deal with the fluid loss from the overnight fast after entering the operating theatre. A standard  
preparation was then performed, including heart rate (HR), lead II ECG, SpO2 (pulse oximetry),  
and end expiratory carbon dioxide. A Bispectral (BIS) index sensor was attached to the patient's  
forehead in conjunction with the BIS Monitor. Cannulation of right radial artery was performed  
under local anesthesia for invasive blood pressure monitoring.   
All patients were preoxygenated by a facemask in the position of neutral. Prior to anesthesia  
induction, the nasal mucosa was well prepared with 1% tetracaine hydrochloride jelly for 2 min  
and five drops of ephedrine hydrochloride nitrofurazone (containing approximately 2 mg  
ephedrine) in all patients. Baseline hemodynamic data were recorded by an investigator after a  
stabilization period of 10 min.   
The nasotracheal tube used was reinforced endotracheal tube (ETT, Safety-Flex with Murphy Eye,  
oral/nasal, Athlone, Ireland; ID 6.5mm in female and ID 7.0mm in male patients) and was well  
lubricated with 1 % tetracaine hydrochloride jelly. Dosing of induction medications was given at  
the discretion of the attending anesthesiologists. Induction agents included midazolam (0.02  
mg/kg), propofol (1.5~2 mg/kg) and fentanyl (2 μg/kg). Upon loss of consciousness and jaw  
relaxation, manual ventilation was tested. If manual ventilation was available, cissatracurium  
besilate (0.15 mg/kg) was administrated and post induction values were recorded 3 min after  
induction. Unsuccessful manual ventilation led to study exclusion.  
The anesthesiologist tried to intubate when the Train of Four (TOF) count reached zero and BIS  
value decreased to 50. NTI was performed in a standard manner. First, a preformed ETT was  
inserted into the nostril and advanced to the posterior nasopharyngeal wall. Second, a  
laryngoscope blade was introduced into the mouth to expose the glottis. If it’s necessary, the  
BURP maneuver (backward, upward, right-sided pressure) on the thyroid cartilage was attempted  
to obtain good glottis visibility. And ultimately, the ETT was inserted into the trachea with the aid  
of Magill’s forceps, head flexion, or cuff inflation if necessary.  
4. Observation outcome:  
 (1) Primary outcome: the intubation time  
 (2) Secondary outcome measures included time to expose the glottis (laryngoscopy time) and  
the view of glottis opening valued by Cormack-Lehane grade. A Cormack-Lehane grade IV was  
defined as laryngoscopy failure. A blinded investigator also recorded the hemodynamic changes  
(MAP, HR) during the procedure of NTI. The maximum values of invasive MAP were recorded.  
After successful intubation, the subjective sensation of the intubator (ease of device insertion,  
quality of view on display and ease of tube advancement) was graded as excellent, good, fair and  
poor. Other intubation parameters included incidences of bleeding or dental injury, number of  
assist maneuvers (use of BURP maneuver, Magill’s forceps, or cuff inflation). Twenty-four hours  
after the procedure, a nurse anesthetist blinded to group assignment recorded the severity of sore  
throat and hoarseness. 
 
Statistical analysis  
Our sample size estimation was based on previous studies (11,23), in which the standard  

deviations (SD) of intubation time were estimated as 8 and 13.7 seconds. To detect a intergroup  
difference of 10 seconds in intubation time with α of 0.05 and β of 0.8, we estimated that 30  
patients would be enough for each group. To compensate for patients dropping out during the  
study, additional patients (10%) were added. The final sample size of 33 patients was in each  
group.   
Mean (SD) or Median (IQR [range]) was used to describe the parametric data. The number  
(percentage) was used to describe nonparametric data. Statistical analyses were performed with  
Prism 5.0 for Windows (GraphPad Software, Inc., La Jolla, California, USA). Binary data for three  
groups were analyzed using chi-square test and each two groups were compared with chi-square  
segmentation method or Fisher's exact test as appropriate. One-way analysis of variance (ANOV A)  
with post-hoc Bonferroni’s Multiple Comparison test was used to analyze parameter data for  
changes within groups. The Kruskal-Wallis ANOV A with post-hoc Dunn’s test was used to  
analyze ordinal data. A p value less than 0.05 was considered as significant.