A Comparative Study Between the Rigid Tube for Laryngoscopy, as a New Tool for Tracheal Intubation, and McIntosh Laryngoscope in Difficult Airway Patients
Phase: NA
Conditions: Intubation;Difficult
Sponsor: Iuliu Hatieganu University of Medicine and Pharmacy

 Tracheal Intubation with the Rigid Tube for Laryngoscopy 
Study Protocol and Statistical Analysis Plan – 05/11/2017 
 
Ioan F. Marchis 
Department of Anesthesiology, University of Medicine and Pharmacy “Iuliu Hatieganu”, Cluj- Napoca, 
(ROMANIA) 
 
 
 
 Corresponding author: Ioan F. Marchis, Department of Anesthesiology, University of Medicine and 
Pharmacy “Iuliu Hatieganu”, No. 8 Victor Babes Str. Cluj Napoca 400012, Romania 
Tel: +40-757-065205 
Fax: +40-264-597257 
E-mail: marchis.ioan@umfcluj.ro 
 ClinicalTrials.gov NCT03341507 
 
 
 
 
 
 
 

 
 
 
 
 Inclusion criteria 
The study will include adult patients with ASA physical status 1–3, requiring surgery for an ENT pathology 
and having a presumed  difficult airway which will be divided in two groups: anatomically difficult airway 
group according to The Simplified Airway Risk Index Scale(SARI), with a SARI score ≥ 5, and patients with 
obstructing airway pathology: oropharyngeal tumors, cervical masses, previous neck surgery or 
radiotherapy, also with predicted difficult intubation forming  group 2.  
The two groups are needed because ENT pathology is generating a particular challenge in airway approach 
which is different from the rest of the pathology and the main goal is to show the efficiency of  Rigid Tube 
for Laryngoscopy (RTL) versus gold standard in intubating patients with various types of airway issues. We 
decided to include at least ten patients in each group, a reasonable number for testing a new method of 
airway control. Signed informed consent was obtained from all patients explaining the procedure in simple 
words and detailing the risks and the safety measures. 
Exclusion criteria 
     Stridor or marked laryngeal or tracheal stenosis, vocal cords polyps, emergency surgery, high aspiration 
risk, decompensated cardiac and pulmonary disease, very poor dentition and patient refusal were criteria 
of exclusion from the study. We’ve also decided to reject from the study patients who exhibit a Cormack-
Lehane grade 1 glottis view when conventional laryngoscopy is performed. In case of difficult mask 
ventilation causing marked desaturation, requiring prompt action to secure the airway, we will take the 
first chance to secure the airway considering potentially unsafe the use of the experimental RTL. The 

investigator underwent a training period before starting the study, consisting in ten direct laryngoscopies 
with the RTL under an ENT specialist guidance to get used to manoeuvring the RTL and acquire a 
reasonable level of skill in using it.  
   A pre-anaesthetic exam was performed with careful assessment of the airway. Patients with features 
predictive for difficult intubation gathering at least 4 points on the SARI score and with no known airway 
pathology were included in group 1. Patients from the group 2, with obstructing airway pathology had a 
perioperative endoscopic examination of the airway with a flexible rhino-laryngoscope which is meant to 
evaluate the distorted anatomy and exclude glottic or subglottic stenosis which could contraindicate blind 
intubation over an intubating tube introducer (gum elastic bougie).  
   Premedication consisted of 1 or 2 mg of Midazolam given intravenously 15 minutes before the 
intervention, in the preoperative room. Standard hemodynamic and respiratory monitoring were applied: 
ECG, non-invasive arterial blood pressure, oxygen saturation, respiratory frequency, end-tidal CO2.  
Difficult airway kit was prepared. The RTL was in position with the light source attached. Patients were pre 
oxygenated for 5 minutes and induction of anesthesia with propofol- succinylcholine and fentanyl was 
performed. After 1 minute of mask ventilation, we noted the oxygen saturation on the pulse oximeter, 
classical laryngoscopy was performed with a McIntosh curved blade laryngoscope, and CormackLehane 
glottis visualization was registered- possible values: 1,2,3,3.5,4. 
     The RTL intubation starts with the head in extension and in sniffing position, using a retromolar 
approach, with teeth protection. The approaching side was chosen based on patient pathology and it could 
be changed during the procedure if the investigator considered so. We used a 1.2-2.2 cm wide and 15-30 
cm long tube depending on patient preoperative assessment and pathology. During advancement of the 
RTL, the investigator is careful to apply the minimum of pressure so the oro-pharyngeal tissue and 
dentition should not be injured. The RTL was advanced slowly until it reached the epiglottis, then the 

epiglottis was lifted, and the vocal cords visualised. The thyroid cartilage was a land point when advancing 
the RTL, keeping the RTL on its direction and holding pressure on it and thus adjusting the larynx position 
so the epiglottis and glottis should be easier to visualise with the RTL. After a proper alignment between 
the RTL and the glottis was achieved, the bougie was introduced through the RTL into the glottis, the RTL 
extracted, and the standard cuffed intubating tube with lubricated tip was placed in the trachea gently, 
over the bougie. Secretions were aspirated through the RTL as needed. If the glottis is visualised during 
the RTL advancement, it will be withdrawing slowly, and the larynx will be manipulated with the left hand 
from the thyroid cartilage until the glottis comes into sight. A second attempt will be started advancing 
slower, heading to the thyroid cartilage while looking for epiglottis. Once epiglottis is lifted the RTL must 
be directed as anteriorly as possible, returning to the epiglottis and starting new lifting if not successful.   
We decided to stop the attempt at 120 s or if the patient desaturated to 80%.  
  We note the Cormack-Lehane glottis visualization at classical laryngoscopy- with values ranging from 1 
to 4, the time from classical laryngoscopy until the airway was secured in seconds, the lowest oxygen 
saturation during the procedure and any other complications occurring during procedure. we document 
every patient data regarding airway, ENT pathology and difficult airway history. We recorded images to 
document the challenging cases and prove the efficiency of the RTL. We also took notice of any 
complications that may have arisen during or after the procedure.  
Statistical analysis plan 
The statistical part will consist of creating a table with the pre-anaesthetic and demographic variables – 
mean and standard deviation. The results will be included in a table and graphic image and the data which 
will be analysed are: 
- time for conventional laryngoscopy and for intubation with the RTL- mean and SD 
- grade of glottis view as from Cormack-Lehane scale- median and full range 

- haemoglobin oxygen saturation during the procedure with the lowest noted as mean and SD 
- complications during and after the procedure