Vie Scope Versus Macintosh Laryngoscope in Expected Easy Airways: A Randomized Controlled Trial
Phase: NA
Conditions: Laryngoscopy
Sponsor: St. Andrew's General Hospital, Patras, Greece

 
 
 
 
 
 
VIE SCOPE VERSUS 
MACINTOSH 
LARYNGOSCOPE IN 
EXPECTED EASY AIRWAYS: A 
RANDOMIZED CONTROLLED 
TRIAL 
 
NCT NUMBER: 
NCT06149338 
 
 
 
 
 
 
21/08/2024 

STUDY PROTOCOL 
 
 
Ethics 
The study protocol was approved by the Scientific Committee (approval number: 
141/09.07.2023). Since the strategies employed in both study groups are considered 
components of standard care, and the study involved patients undergoing elective and 
nonelective surgery or being treated in the emergency settings, the committee waived 
the necessity for written informed consent. The study was registered on 
ClinicalTrials.gov (NCT06149338) on 04.01.2024 and was in accordance with the 
principles of the Declaration of Helsinki and Good Clinical Practice guidelines. 
Study design 
A prospective, randomized, single-blind, superiority, clinical trial has been conducted 
since 26.01.2024. The intubations were performed by the same resident of 
anesthesiology, who had already completed successfully at least 50 intubation 
attempts with each one of the two examined laryngoscopes, before the beginning of 
the patient enrollment into the study, in order to eliminate any impact from a different 
learning curve of any laryngoscope and to gain competency, although concurrently 
there are limited data for Vie Scope, fostering its short learning curve, despite the 
mentioned necessity of previous practice with straight blade devices. Every 
intervention was made under the supervision of an experienced Anesthesiologist 
consultant. In case of certified or possible COVID-19 infection of the patient, the 
airway operator was instructed to use the required PPE. 
The current study included patients of both sexes. Apart from the gender, the age (≥ 
18 years old) and the Body Mass Index (B.M.I.: 18.5 – 30 kg/m2) were considered as 
inclusion criteria of this study. A positive or negative rapid test for COVID-19 or 
possible contamination of the patient was documented as well, without affecting the 
patient’s eligibility for the study inclusion. Also, every patient underwent an adequate 
airway assessment, including airway history and physical examination, preoperatively 
or in the emergency settings, when feasible, to distinguish the patients with 
anticipated easy airways management. The chin protrusion (upper lip bite test), the 
thyromental distance and the Mallampati score were mostly evaluated, due to their 
efficacy in detecting an anticipated difficult airway. Consequently, the higher a 
patient could bite the upper lip with the lower incisors, the thyromental distance > 3 
ordinary fingerbreadths and the Mallampati scores 1, 2 were positive predictive 
factors of an expected easy airway. Despite the high sensitivity of the upper lip bite 
test, the low sensitivities of other tests, such as the Mallampati score, and the confined 
airway assessment in emergency settings or patient cooperation necessitated the 
adoption of the Cormack - Lehane classification as a recruitment criterion of this 
study. According to this scale, the glottis visualization grades 1, 2a, 2b, after direct 
laryngoscopy, were compatible with easy endotracheal intubation, making these 
patients eligible participants in the present study. In contrast, patients with age under 
18 years old, with BMI under 18.5 kg/m2 and over 30 kg/m2, inability to bring 
mandibular incisors anterior to maxillary incisors, thyromental distance < 3 ordinary 

fingerbreadths, Mallampati scores 3, 4 and Cormack - Lehane classification grades 3 
and 4 were excluded from this clinical trial. 
The randomization of the patients was generated immediately before the anesthesia 
induction, after the investigator Anesthesiologist trainee was assigned to the patient, 
either in the operating room or in the emergency settings, using sealed opaque 
envelopes, that contained demographic data and medical background of the 
participants in pseudonymized form. The allocation ratio was 1:1 to either Vie Scope 
or Macintosh laryngoscope. The patients remained blinded to the intervention 
procedure, while this was not feasible for the airway operator, due to the study’s 
nature. 
Patients, being randomized into the intervention group, underwent direct 
laryngoscopy and subsequent intubation attempt with the Macintosh laryngoscope 
(HEINE Optotechnik GmbH & Co. KG, Gilching, Germany), (Figure 1). The size of 
the blade (3 or 4) was chosen at the discretion of the Anesthesiologist trainee. The 
airway operator implemented the midline approach for the displacement of the tongue 
from the area of view and placed the tip of the Macintosh blade in the epiglottic 
vallecula, so as to achieve the indirect elevation of the epiglottis and exposure of the 
vocal cords, followed by the endotracheal intubation. 
Patients, being randomized into the control group, received direct laryngoscopy and 
ensued intubation attempt with the Vie Scope® (Adroit Surgical LLC, Oklahoma 
City, OK, USA) (Figure 2). The introduction of the Vie Scope into the patient’s 
mouth could be performed by either of the mouth corners, according to the patient’s 
anatomical characteristics. The gentle back tilt of the head was followed by the 
application of the paraglossal or retromolar approach, for aligning the oral, 
pharyngeal and laryngeal axis. After its forwarding, until the glottis was visualized, 
by elevating directly the epiglottis, a 15 Fr bougie with colorful bands, the VOIR 
Bougie (Adroit Surgical LLC, Oklahoma City, USA), was introduced appropriately 
endotracheally, through the cylindrical lumen of the intubation channel of the Vie 
Scope. The careful removal of the Vie Scope was followed by the endotracheal tube 
(ETT)’s railroading over the bougie. As soon as the ETT was positioned, the bougie 
was removed too. 
After the tube’s cuff was inflated, until there was no air leak from the trachea, the 
correct ETT’s placement was verified in both groups by the patient’s ventilation. The 
choice of the size and the type of the ETT was at the discretion of the airway operator. 
In addition, the laryngeal view was estimated, under direct laryngoscopy with each 
laryngoscope, according to the Cormack - Lehane grading system. The airway 
operator was prompted to perform any external laryngeal manipulation, such as the 
backward, upward, rightward pressure (BURP), or to use any assistant equipment, 
like bougies, stylets, forceps, lubricant gel or spray, for optimizing the laryngeal view 
and facilitating the intubation process. The supervisor consultant would be involved in 
case of two failed intubation attempts by the trainee, or whenever the situation 
required the intervention of an experienced Anesthesiologist. 
Outcome measures 

The primary outcome measures were the first attempt intubation success rate and the 
required mean intubation time. The intubation time was defined as the time interval 
from the insertion of the laryngoscope into the patient’s mouth, until the inflation of 
the ETT’s cuff of each patient. 
Contrarywise, the overall intubation success rate and the glottis visualization, based 
on the Cormack - Lehane classification, were regarded as the secondary outcomes. 
 
 
STATISTICAL ANALYSIS 
 
 
The statistical analysis was performed with SAS version 9.4 (SAS Institute, Cary, NC, 
USA) along with Microsoft Excel 2007 for data collection. For the descriptive 
statistics, quantitative variables were presented as means and standard deviations (SD) 
as well as using medians and quartiles 1 and 3 (Q1 and Q3 respectively). Qualitative 
variables were presented using the relative frequencies and the relevant percentages. 
For the inferential part of the analysis, the Kruskal – Wallis test was applied for the 
analysis of numerical data, because they did not follow a normal distribution, 
according to the Kolmogorov - Smirnov test, while the x2 test and, if required, the 
Fisher’s exact test were performed for the categorical data. All tests were two-sided, 
the confidence intervals (CIs) were determined as 0.95 and thus significance cut-off 
level was for p < 0.05.