A Comparison of Direct Laryngoscopy and Video Laryngoscopy Using the C-Mac in Pediatric Nasal Intubations
Phase: NA
Conditions: Nasal Intubation
Sponsor: Wake Forest University Health Sciences

Protocol version: 
Updated 16.3.10 
1 
 
 
 
 
 
 
 
 
 
A comparison of direct laryngoscopy and video 
laryngoscopy using the C-Mac in pediatric nasal 
intubations. 
 
NCT03032263 
March 10, 2016

Protocol version: 
Updated 16.3.10 
2 
 
Study Title: A comparison of direct laryngoscopy and video laryngoscopy using the C-Mac in pediatric 
nasal intubations. 
 
Principal Investigator, Co-investigator(s): T. Wesley Templeton M.D., Kristin Henderson CRNA, 
 
Sponsor or funding source: Wake Forest Department of Anesthesia 
 
Background, Rationale and Context 
 
Nasal intubation is frequently used for dental procedures to promote an unimpeded view of the oral 
cavity. Following the induction of general anesthesia, the patient is given a dose of muscle relaxant. At 
this point, a vasoconstrictive agent such as oxymetazoline is commonly introduced into both nares to 
reduce the incidence of nasal bleeding. 6, 7 After this step, an appropriately sized nasal RAE (Ring, Adair 
and Elwyn) endotracheal tube, an endotracheal tube designed specifically for intubations secured by way 
of the nasal passage, is introduced into the nare that is associated with the least resistance. The nasal tube 
is then placed through the nasal passage and into the posterior pharynx, then advanced into the airway. A 
nasal RAE endotracheal tube is longer than a standard oral endotracheal tube (ETT) and it is shaped so 
that end of the tube which attaches to the ventilator exits upward toward the forehead.  This unique shape 
ensures that the tube will not interfere with surgical exposure of the oral cavity and mandible.  
 
The nasal RAE ETT can be placed in the trachea using either direct laryngoscopy or video laryngoscopy. 
In the case of direct laryngoscopy, following placement of the nasal RAE into the nasal passage, a 
laryngoscope is introduced into the oral cavity. The nasal RAE tube is advanced slowly until it is 
visualized in the oropharynx via the laryngoscope. Simultaneously, the practitioner attempts to visualize 
the glottic opening. The practitioner will then attempt to guide the distal end of the Nasal RAE ETT into 
the glottis. Sometimes this is possible without an adjuvant, but frequently a pair of specially shaped 
forceps, known as Magill forceps, is required to guide the distal tip of the Nasal RAE into the glottis due 
to the curvature of these ETT. 1, 2 Magill forceps are introduced into the mouth and are used to grasp the 
distal end of the Nasal RAE and direct it into the glottis. 
  
Video laryngoscopy is a more modern approach to direct laryngoscopy in which a camera is present on 
the blade of the laryngoscope. This is different in some ways from direct laryngoscopy because the 
location of the camera on the blade allows for visualization of the glottic opening and other oropharyngeal 
structures without requiring a direct line of site. This can potentially facilitate intubation in more 
challenging airways because there no longer is a need for direct line of site to place the ETT into the 
glottis.  At this time there are a number of different devices available from different manufacturers 
including the C-Mac (Karl Storz, Germany), the Glidescope (Verathon), and the Mcgrath (Covidien). 3, 5 
 
In a recent study looking at nasal intubation in children using the Glidescope, investigators found a fairly 
equivalent rate of successful intubation with DL and VL using a Glidescope. They found similar time to 
intubate and similar incidences of having to use the standard Magill forceps (90% in DL vs 87.5% in VL) 
in order to place the Nasal RAE tube. They also failed to intubate nasally with the Glidescope in 2 
individual cases.1, 4 
 
In another study looking at nasotracheal intubation in adults with a known difficult airway, the 
researchers examined the impact of modifying the shape of the Magill forceps to improve the success rate 
of intubation. They compared 3 different video laryngoscopic systems including the Glidescope, Airtraq, 
and C-Mac. They found that modifying the shape of the Magill forceps did improve the rate of intubation. 
However, there is no comment on whether or not the use of VL with any of these 3 systems reduced the 
rate of needing Magill’s forceps overall.2 

Protocol version: 
Updated 16.3.10 
3 
  
Contrary to what some of these studies suggest, it has been our experience that nasal intubations using the 
C-Mac frequently do not require the use of Magill forceps at nearly the same rate as DL additionally they 
may overall be easier. As a result, this technique may improve the over all time and ease of intubation 
because of not having to use the Magill forceps to advance the Nasal RAE into the larynx. The use of 
Magill forceps can be awkward for the clinician, with poor visualization due to obstruction of the view by 
this tool in the airway, and small working space within the posterior oropharynx.  For these reasons, the 
possibility of not having to use Magill forceps because we are using a C-Mac as the only tool to intubate 
is a potentially inviting one. Overall there may be other positive effects to having a closer and more 
magnified view of the glottis as well.  
 
Objectives 
 
The objective of this study is to compare the need for the use of standard Magill forceps when performing 
a nasal intubation with either conventional DL or VL with a C-Mac and overall ease of intubation. 
Secondarily we will also examine the time to intubate (TTI) for both methods as well. 
 
An additional objective will be to assess if there are any other significant clinical differences between 
these two approaches to placement i.e. increased rates of overall failure, clinical morbidity such as 
laryngeal or pharyngeal injury. 
 
Methods and Measures 
 
Design 
 
Once the patient is recruited in the pre-admission clinic (PAC), this information will be relayed to 
the study investigators. On the day of surgery, the patient will then be randomized using a random 
number generator and opaque envelope method for group allocation to either DL or VL with a C-
Mac. In a minority of cases where a suitable patient has not gone through the PAC we will 
attempt to recruit them prior to going to the operating room after the pre-anesthetic evaluation. 
 
We will record age, height, weight, gender, ASA status. 
 
The patient will be pre-medicated at the discretion of the attending anesthesiologist. The patient 
will then be randomized to either DL or VL with a C-Mac. The patient will be brought to the 
operating room. Once in the OR the patient will have routine monitors placed. The patient will 
undergo an inhalational induction with sevoflurane. Once anesthesia has been induced, an IV will 
be placed. The patient will be relaxed with 0.8 mg/kg of rocuronium IV. The patient will then be 
hand-ventilated with 100% oxygen and sevoflurane for 3 minutes to allow for adequate relaxation 
and an end tidal oxygen concentration of at least 80%. During this time, the patient will receive 
oxymetolazine in both nares to reduce the risk of bleeding with a nasal tube. Prior to intubation, 
we will also attempt to insert an appropriately sized flexible nasal trumpet to assess which nares 
provides the least resistance to passage of an ETT. After 3 minutes have elapsed since the 
administration of rocuronium, an appropriately sized cuffed nasal RAE ETT that has been 
warmed using a warm blanket, and then lubricated with a water soluble lubricant will be inserted 
into the nares. Once the ETT is passed into the posterior oropharynx, depending on which 
randomized group the patient has been assigned (VL or DL), an attending pediatric 
anesthesiologist or a pediatric Certified Registered Nurse Anesthetist (CRNA) who has 
experience performing nasal intubations with both DL and with the C-Mac will attempt to 
intubate the patient with or without Magill forceps as needed. 
 

Protocol version: 
Updated 16.3.10 
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We will record the time to intubation (TTI) from the time the laryngoscope or C-Mac is placed in 
the mouth to the first appearance of end tidal carbon dioxide (ETCO2). We will record the 
presence or absence of nasal bleeding and its level of severity using a 4 point scale(0 No 
bleeding, 1-Trace, 2-Moderate, 3-copious) as well as the grade of laryngeal view. We will record 
the number of attempts. If the blade is removed from the mouth this will be considered the end of 
one attempt, and once the blade is reinserted this will be the beginning of another attempt.  
We will also record any general narrative comments from practioners about the ease or difficulty 
of intubation in both the DL and VL group. In addition to the narrative comments we will have 
the laryngoscopist grade the degree of difficulty on a 100mm VAS scale after the intubation (0 
easiest -100 most difficult). The laryngoscopist will be blinded to TTI until VAS score and other 
airway data are recorded. Intubation will be considered a failure at 5 minutes. At this point it will 
be at the discretion of the anesthesiologist of record to decide how to proceed, either with an oral 
tube or different technique for nasal intubation. TTI will be considered 5 minutes for the purposes 
of analysis and device comparison. We will record the lowest SpO2 during intubation. 
 
The patient will be extubated according to normal clinical practices and will be taken to the post 
anesthesia care unit (PACU). 
 
Patients will be observed in the PACU and any significant events such as unintended admission, 
excessive hoarseness, persistent nasal bleeding, or pharyngeal injury will be recorded. 
 
The study will be performed at Wake Forest Baptist Medical Center a tertiary academic medical 
center. 
 
C-Mac Product Information 
 
The C-Mac Video laryngoscope is produced by Karl Storz products. Product specifications can be 
found at: 
https://www.karlstorz.com/cps/rde/xbcr/karlstorz_assets/ASSETS/3436753.pdf 
 
http://www.airwayworld.com/wp-content/uploads/2013/08/1.-C-MAC-VIDEO-
LARYNGOSCOPES.pdf 
 
http://www.airwayworld.com/wp-content/uploads/2013/08/Neonate-Pediatrics.pdf 
 
 
 

Protocol version: 
Updated 16.3.10 
5 
Subjects selection criteria 
 
Pediatric patients between the ages of 3 and 14 scheduled for comprehensive dental treatment in which a 
nasal tube would be an appropriate method to secure of the airway. 
 
 
 
Inclusion Criteria 
 
Patients between the ages of 3 and 14 scheduled for comprehensive dental treatment, tooth 
extraction, or incision and drainage of tooth abscess under general anesthesia in which a nasal 
endotracheal tube is an appropriate method for securing the airway. 
Normal appearing airway upon pre-operative assessment. 
 
 
Exclusion Criteria 
 
Patient with a history of difficult airway/intubation 
Patients suspected to have a difficult airway.  
History of cleft palate and/or cleft palate repair 
Pregnancy 
Emergency status of surgery 
Any patient with a contra-indication to nasal tube placement 
Any patient with a potentially increased risk of nasal bleeding from nasal placement of the 
ETT i.e. patients on aspirin or other anticoagulants, patient’s with hemophilia,   
 
 
Sample Size 
 
Based on a published rate of approximately 90% of patients requiring Magill forceps to place 
a Nasal RAE ETT with DL and a rate of 50% based on pilot data in patients with a C-Mac 
VL system, we have performed a power calculation to determine the sample size needed. 
Based on a power of 80% and an alpha of 1% we have calculated a sample size of 35 patients 
in each group to be able to detect a significant difference in the rate of use of Magill forceps 
to place a nasal RAE ETT in this patient population. This is not a multi-site study.  
 
 
Interventions and Interactions 
 
Interventions and interactions for the patient should be fairly reasonable. The largest overall commitment 
of time from the patient will be in the PAC or preoperatively in holding at the time of recruitment. One of 
the PAC investigators interview the patient’s legal guardian (frequently their parents) and the patient for 
assent when appropriate. They will explain the study and attempt to recruit the patient if they are eligible. 
The study participant and their guardian will have their questions answered and if they agree to allow 
their child to participate will sign the consent form. Assent will be obtained from cognitively intact 
children over the age of 7. 
 
In patients that have gone through and been recruited in the PAC, the patient will be identified in the 
holding area on the day of surgery and a study representative will make sure that the guardian or patient 
has not changed their mind about participation and will answer any questions the study subject may have 
thought of since the interview in PAC. If the patient’s guardian is still in agreement to participate in the 
study they will be taken to the OR and care will proceed as it would otherwise with the induction of 
general anesthesia and attempted placement of a nasal RAE ETT via DL or VL with a C-Mac depending 
on which randomization group to which the patient has been randomized. After the procedure, the patient 

Protocol version: 
Updated 16.3.10 
6 
will be observed in the PACU and discharged to home. A study representative will thank them for their 
participation and this will be the last interaction with the patient and patient’s guardian in the study. 
 
 
Patient 
identified 
in PAC. 
Patient 
approached 
in PAC and 
questions 
answered 
about. 
Patient to 
sign consent 
for study 
participation 
here.  
Confirmation 
and 
randomization 
on day of 
surgery 
Patient 
intubated 
after 
induction of 
anesthesia. 
Data 
collected 
about nasal 
intubation 
including 
time to 
intubate and 
laryngeal 
view. 
Patient 
will 
undergo 
dental 
procedure.  
At the end 
of the 
dental 
procedure. 
The ETT 
will be 
removed 
and the 
patient 
will be 
taken to 
PACU 
Patient will 
be observed 
and 
recovered 
post 
operatively 
in the 
PACU. Any 
significantly 
airway 
injuries or 
recurrent 
nasal 
bleeding 
will be 
noted. 
Time 
required 
of 
Patient 
0 min 
20 min 
5 min 
10 min 
Depends 
on 
surgical 
duration. 
5 minutes 
5-10 min 
 
 
Outcome Measure(s) 
 
We will record time to intubate and will assess the need for Magill forceps for intubation. We will also 
record grade of larynx view, presence of nasal bleeding, any and all comments from the practitioner 
related to intubation, and incidence of failed nasal intubation. 
 
Analytical Plan 
 
Results will be analyzed initially using descriptive statistics.  Comparison between the two groups will be 
done using Fisher’s Test, and ANOVA procedures for continuous variables. Other inferential statistical 
analysis will be conducted as appropriate. 
 
Human Subjects Protection 
 
Subject Recruitment Methods 
 
In most cases patients will be identified for participation in the Preoperative Assessment Clinic (PAC) 
prior to the day of surgery. Almost all pediatric patients scheduled for elective dental procedures pass 
through the PAC. In some cases though, patients do not go through the PAC and we will attempt to 
identify and recruit these patients in preoperative holding using the same inclusion and exclusion criteria. 
Patients will be recruited and consented by investigators with the participation and collaboration of the 
PAC attending present in the clinic. We will attempt to recruit qualified subjects in a non-biased manner. 
Privacy will be protected because subjects will be recruited in the process of a confidential preoperative 
evaluation in PAC. If they choose not participate no research record will be created and as such there will 
be no contact information to destroy. 
 

Protocol version: 
Updated 16.3.10 
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Informed Consent 
 
Signed informed consent will be obtained from the parent or legal guardian of each subject. Informed 
consent will be obtained by investigators. This consent will be obtained in the PAC when ever possible, 
however we may obtain consent on the day of surgery in patients that have not gone through the PAC. 
Assent will also be obtained for children over the age of 7 who are cognitively able to provide assent. 
However, in many cases these patients present with a medical history of mental handicap or autism and 
will not be able to give assent. 
 
Confidentiality and Privacy 
 
Confidentiality will be protected by collecting only information needed to assess study outcomes, 
minimizing to the fullest extent possible the collection of any information that could directly identify 
subjects, and maintaining all study information in a secure manner.  To help ensure subject privacy and 
confidentiality, only a unique study identifier will appear on the data collection form.  Any collected 
patient identifying information corresponding to the unique study identifier will be maintained on a 
linkage file, stored separately from the data.  The linkage file will be kept secure, with access limited to 
designated study personnel.  Following data collection, subject identifying information will be destroyed 
4 years after closure of the study via shredding, consistent with data validation and study design, 
producing an anonymous analytical data set.  Data access will be limited to study staff.  Data and records 
will be kept locked and secured, with any computer data password protected.  No reference to any 
individual participant will appear in reports, presentations, or publications that may arise from the study. 
 
Data and Safety Monitoring 
The principal investigator will be responsible for the overall monitoring of the data and safety of study 
participants.  The principal investigator will be assisted by other members of the study staff. 
 
Reporting of Unanticipated Problems, Adverse Events or Deviations 
Any unanticipated problems, serious and unexpected adverse events, deviations or protocol changes will 
be promptly reported by the principal investigator or designated member of the research team to the IRB 
and sponsor or appropriate government agency if appropriate. 
 
References 
 
 
[1] Kim HJ, et al. “A comparison of GlideScope videolaryngoscopy and direct laryngoscopy for 
nasotracheal intubation in children. Pediatric Anesthesia 2011; 21: 417-421. 
 
[2] Staar S, et al. “Nasotracheal intubation with three indirect laryngoscopes assisted by standard or 
modified Magill forceps.” Anaesthesia 2013; 68: 467-471 
 
[3] Sun Y et al. “Pediatric video laryngoscope versus direct laryngoscope: a meta-analysis of randomized 
controlled trials. Pediatric Anesthesia 2014; 24:1056-1065 
 
[4] Kim JT et al. “Glidescope video laryngoscope: a randomized clinical trial in 203 paedetric patients.” 
British Journal of Anesthesia 2008; 101: 531-534 
 
[5] Vlatten A, et al. “A comparison of the STORZ video laryngscope and standard direct laryngoscopy for 
intubation in the Pediatric airway-a randomized clinical trial.” Pediatric Anesthesia 2009; 19:1102-1107 

Protocol version: 
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[6] Krempl GA, et al. “Use of oxymetazoline in the management of epistaxis.” Annals of Otol Rhinol 
laryngolog 1995; 104: 704-706 
 
[7] Riegle EV, et al. “Comparison of vasoconstrictors for functional endoscopic sinus surgery in 
children.” Laryngoscope 1992; 102: 820-823. 
 
 
 
Appendix 
1. Data collection form 
2. Consent form