Comparison of Miller and Macintosh Laryngoscopes, CMAC and Glidescope Videolaryngoscopes in Inexperienced Users: a Pediatric Manikin Study
Phase: NA
Conditions: Videolaryngoscopes (VL), Direct Laryngoscopy (DL), Inexperienced Users
Sponsor: Joseph D. Tobias

NCT02991820 
IRB16-00549 
6/24/16 
 
Title: Comparison of Miller and Macintosh laryngoscopes, CMAC 
and Glidescope videolaryngoscopes in inexperienced users: 
a pediatric manikin study. 
 
Investigators: Joseph D. Tobias, MD 
 
Describe the background and rationale for this project:  
 
The commonly used method for endotracheal intubation in children 
is direct laryngoscopy using a Miller or Macintosh blade. 
Videolaryngoscopy is a widely accepted 
pediatric airway 
management. Videolaryngoscopes (VL) provide an indirect view of 
glottis without the need to align the oral, pharyngeal, and glottis 
structures. Some types of VLs provide also direct view of glottis 
with indirect view.  Videolaryngoscopes can be used as a teaching 
tool for learners as they can visualize all the anatomical structures 
of larynx at the same time with the performer.  VLs may facilitate 
the learning of endotracheal intubation in inexperienced users in 
the pediatric population. There are limited data on the use of 
videolaryngoscopes 
by 
anesthesia 
providers 
and 
medical 
personnel 
who 
are 
inexperienced 
in 
the 
use 
of 
videolaryngoscopes. 
 
How will your study be funded: No funding is required for this 
study. 
 
Provide a potential start date and end date for your study to 
be included in the IRB application: start date of 6/27/2016 – end 
date of 7/30/2016 (1 month period). 
 
List any sub-Investigators you want to participate as back-
up/support on the study - Julie Rice, Heather Dellinger, SAM 
Barry 
 
Describe the significance of the proposed research: To 
compare the CMAC and Glidescope videolaryngoscopes (VL) to 
traditional direct laryngoscopy (DL) using either a Miller or 
Macintosh laryngoscope by studying the performance of users. 
This will involve the use of an intubating pediatric manikin to 

assess various aspects of endotracheal intubation by experienced 
and inexperienced users. The inexperienced users in intubation of 
children will use VLs on a pediatric manikin. We will evaluate the 
success rates of inexperienced and experienced users and 
compare their results. These results will help us to see if 
inexperienced users are successful with VLs.  Also we will assess 
whether VLs are a good teaching tool and if they can be preferred 
as a first line tool for pediatric intubation. 
 
State the primary and secondary objectives of the study: The 
goal of the study is to test whether time to intubation is shorter with 
VL as compared to DL. We hypothesize that this difference will be 
greatest for users with the least experience in DL. Secondary aims 
include comparing success rates and user-rated ease of intubation 
between VL and DL. 
 
If this research is hypothesis driven, succinctly state the 
hypothesis: Performers who are inexperienced about direct 
laryngoscopy and VL will achieve higher overall success rates 
using videolaryngoscopes than using a direct laryngoscope. 
 
Outline the major steps and methodologies in the clinical 
protocol.  Direct laryngoscopy using a Miller and Macintosh 
laryngoscope as well as indirect laryngoscopy using a CMAC and 
Glidescope VL devices will be used.  Each participant will perform 
endotracheal intubation on the mannequin using both types of 
laryngoscope blades and both types of indirect laryngoscopes 
(total of 4 intubation attempts each). In a given subgroup, a two-
tailed paired t-test on a sample of 10 subjects would have 80% 
power to detect a 15s difference in time to intubation between 
videolaryngoscopy and direct laryngoscopy at a 95% confidence 
level, assuming mean time to intubation of 45 ± 15 seconds with 
videolaryngoscopy and low within-subject correlation (r=0.5) 
between times to intubation with the different methods in the study. 
Therefore, the study will recruit 10-20 personnel from each of the 
following 4 groups: 
 
1. Faculty pediatric anesthesiologists  
2. CRNAs 
3. Trainees (SRNAs, residents, and fellows, and medical students)  
4. APNs from the PICU/CTICU.Nurses at NCH  
 
 

Time to endotracheal intubation, the number of intubation 
attempts, and the rate of successful endotracheal intubation on 
first attempt and success of endotracheal intubation within 120 
seconds will be recorded. The subjective (rating 1 to 10) for ease 
of device use and laryngoscopic view judged by the percentage of 
glottic opening score (POGO) will be recorded. Comparison of 
these values between experienced and inexperienced users will be 
performed as well as comparison of CMAC, Glidescope, Miller 
blade, and Macintosh blade.  
 
  
Identify the variables to be measured and how they will be 
statistically evaluated:  
Time to endotracheal intubation, the number of intubation 
attempts, and the rate of successful endotracheal intubation on 
first attempt and success of endotracheal intubation within 120 
seconds will be recorded. The subjective (rating 1 to 10) for ease 
of device use and laryngoscopic view judged by the percentage of 
glottic opening score (POGO) will be recorded. Comparison of 
these values between experienced and inexperienced users will be 
performed as well as comparison of CMAC, Glidescope, Miller 
blade, and Macintosh blade. Pairwise comparisons among 
laryngoscopy methods will be performed using paired t-tests for 
continuous data and McNemar tests for categorical data. 
Repeated measures ANOVA will be used to assess the 
moderating effect of user experience on the difference in time to 
intubation between VL and DL. 
 
 
 
References 
 
1. Lye ST, Liaw CM, Seet E, Koh KF. Comparison of results 
from novice and trained personnel using the Macintosh 
laryngoscope, Pentax AWS®, C-MAC™ and Bonfils 
intubation fibrescope: a manikin study. Singapore Med J 
2013;54:64-8. 
2. Sharma DJ, Weightman WM, Travis A. Comparison of the 
Pentax Airway Scope and McGrath Videolaryngoscope with 
the Macintosh laryngoscope in tracheal intubation by 
anaesthetists unfamiliar with videolaryngoscopes: a manikin 
study. Anaesth Intensive Care 2010;38:39-42. 

3. Ray DC, Billington C, Kearns PK, Kirkbride R, Mackintosh K, 
Reeve CS, et al. A comparison of McGrath and Macintosh 
laryngoscopes in novice users: a manikin study. Anaesthesia 
2009;64:1207-10.