Video Laryngoscopy Versus Direct Laryngoscopy for Nasotracheal Intubation

Comparison of video-assisted laryngoscopy and direct laryngoscopy for routine nasotracheal
intubation in oral and maxillofacial surgery patients: a randomized controlled trial.

INTRODUCTION Nasotracheal intubation is a common method for securing an advanced airway
during surgery for procedures that involve manipulation of the oral cavity, the dentition, or
the facial bones. The placement of a nasotracheal tube is often more challenging, especially
for learning providers, even for patients with normal airway anatomy. Video laryngoscopy is
an adjunctive technique in anesthesia that utilizes a camera at the tip of the laryngoscope
blade and provides an indirect view of the glottis during intubation through display on a
monitor. The use of video laryngoscopes has been shown to reduce time to intubation, result
in perception of easier intubation by the anesthesia team, and reduce the use of adjunctive
maneuvers during intubation. There is little evidence, however, to show these benefits for
routine nasotracheal intubation. The purpose of the study is to compare the ease of
video-assisted laryngoscopy and direct laryngoscopy in routine nasotracheal intubation for
Maxillofacial procedures. The investigators hypothesize that the use of video-assisted
laryngoscopy for routine nasotracheal intubation will increase the rate of success on first
intubation attempt, result in quicker time to intubation, less adjunctive maneuvers and
anesthesia perception of easier intubation when compared to direct nasotrahceal intubation.
The investigators aim to compare the rate of first attempt intubation success, time to
intubation, number of adjunctive maneuvers and the perception of intubation difficulty in
routine nasotracheal intubation for Maxillofacial procedures for video-assisted laryngoscopy
and direct laryngoscopy.

METHODS Study Sample After obtaining institutional review board approval (IRB #10272), the
authors will design a randomized clinical trial. The eligible study population will include
all patients who presented to University Medical Center in New Orleans, LA for oral and
maxillofacial surgery to be performed under general anesthesia and planned for a nasotracheal
intubation. The inclusion criteria for the study will be as follows: planned for a general
anesthetic with nasotracheal intubation, ASA I and II and at least 18 years of age. Prisoners
and patients with anticipated difficult airways will be excluded from this study.

Study Design This will be a single center, parallel group, unblinded randomized controlled
trial with an allocation ratio of 1:1. Because the investigators hypothesized that
video-assisted laryngoscopy would increase the rate of success of intubation on the first
attempt and previous data shows this trend in a similar patient population (Tabrizi et al
2018), this trial will be designed to assess for superiority of the video-assisted
laryngoscopy. One of the investigators will explain the risks and benefits of participation
in the study in detail to each patient and patients will be enrolled in the study after
signing informed consent. A co-investigator, not involved with enrollment or the anesthetic,
will use a computerized research randomization software (www.randomizer.org) to perform block
randomization with randomly varying block sizes of 2, 4 and 6. Then, he will place a paper
with the group allocation written on it into sequentially numbered envelopes in the order
determined by the randomization software. The group allocation will be concealed by using
opaque envelopes that will be sealed after the paper with the group assignment is placed in
the envelope. When a patient is enrolled in the study, the next envelope in the sequence will
be labeled with the patient's study ID and opened by the principal investigator, who ensured
the anesthetic team then performed the technique for intubation assigned to the patient. The
direct, or conventional, laryngoscopy group will undergo the planned nasotracheal intubation
utilizing a Macintosh or Miller laryngoscope for direct visualization of the larynx. The
video-assisted laryngoscopy group will undergo the planned nasotracheal intubation utilizing
a Storz C-MAC S Video Laryngoscope to allow for indirect visualization of the larynx.

Variables The primary outcome variable will be the success of first attempt intubation.
Success of intubation will be defined as confirmed placement of the endotracheal tube by
bilateral breath sounds, end-tidal CO2 waveform and lack of cuff leak. The secondary outcome
variables will be the amount of time required to secure the nasotracheal tube, the use of
Macgill forceps, the success at first attempt, the number of attempts, the number of
endotracheal tube exchanges after placement and the number of torn endotracheal tube cuffs.
Time for intubation will be recorded for each case by an independent observer using a
stopwatch which will start upon removal of the bag mask and will end after the
anesthesiologist confirmed bilateral breath sounds, an end-tidal CO2 waveform and lack of
cuff leak. Use of Macgill forceps will be recorded by an independent observer upon their use
during intubation. An attempt at intubation will be considered failed when the laryngoscope
is removed from the mouth prior to insertion of the endotracheal tube and bask mask
ventilation is restarted. Tube exchanges will likewise be recorded if they occur.

The predictor variable will be the laryngoscopy technique employed: video-assisted
laryngoscopy (the experimental group) or direct Macintosh or Miller laryngoscopy (the control
group). Other variables that will be recorded are age, gender, ASA score and procedure
performed.

Sample Size Calculation The sample size for the study was calculated based on a difference of
10% in first attempt success rate between groups. The investigators regarded this amount of
time as the smallest meaningful difference. Previously published reports was used to base the
sample size calculation, using a success rate of 82% and 60% for first attempt at video
laryngoscopy and direct laryngoscopy, respectively. An estimated sample size of 48 patients
(24 in each arm) will be needed to detect a difference of 10% in first attempt success rate
between the groups with an 80% power and alpha level of 0.05. [A previously published study
(Rabrizi et al 2018) assessed first attempt success rate in patients with bilateral
mandibular fractures in Glidescope video laryngoscopy versus Macintosh laryngoscopy. They
found a first attempt success rate of 82% using a video laryngoscopy versus 60% using direct
laryngoscopy.] Data Collection and Analysis To organize data collection, a Microsoft Excel
spreadsheet will be created and used to record information, which will be kept on a secured
LSU drive which only the investigators have access to. Data will be compiled and imported
into JMP Statistical Discovery for analysis (JMP, Version 12.1. SAS Institute Inc., Cary, NC,
1989-2015). The relationship of the primary outcome variable to the primary predictor will be
analyzed using Chi squared tests. The relationship of the secondary outcome variables to the
primary predictor will be analyzed using Chi squared tests and t tests, as appropriate for
the data type. Study variables will be examined for their relationship to the primary
predictor and primary outcome using t test, Chi squared test and ANOVA as appropriate for the
type of variable. A p-value of less than 0.05 will be considered significant.

Inclusion Criteria:

- oral and maxillofacial surgery to be performed under general anesthesia

- planned for a general anesthetic with nasotracheal intubation,

- ASA I and II

- at least 18 years of age

Exclusion Criteria:

- prisoners

- anticipated difficult airways