Airway Management Via the Retromolar Route Access

Study Overview
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Brief Summary
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Is there a difference in vocal cord visualization between the retromolar and conventional access?

Detailed Description
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Management of the difficult airway is still an essential part of modern anaesthesia. Up to now, there have bee no clinical investigations comparing the intubation method via the retromolar route (RM), with the conventional intubation route (CM). For the present clinical investigation, 100 patients undergoing elective surgery will be investigated in the General Hospital of Vienna when for the anaesthesia intubation is required. In both intubation methods (RM and CM) the anaesthesiologist will visually determine the Cormack & Lehane score in a randomly assigned sequence with and without a BURP-manoeuvre (= backwards, upwards and rightwards pressure). Thereafter intubation is performed in all patients by the CM method and if intubation fails the RM technique will be used. Of course, as per usual, every intubation trial is interrupted by a 20 second 100%-oxygen-ventilation period to reach a pulse oximetry oxygen saturation of at least 97% SpO2. Thereafter, if intubation fails again every other intubation technique will be applied, as necessary and called for.

Official Title
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Airway Management Via the Retromolar Route Access - a Clinical Study

Conditions
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Airway Management, Intubation

Intervention / Treatment
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* Other: Retromolar Vocal Cord Visualisation
* Other: Conventional Vocal Cord Visualisation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 18yr BMI < 30kg/m2 Elective surgery Absence of at least one molar of the right mandible Exclusion Criteria: Emergency patients Prevalence of reflux disease Toothless patients Diaphragmatic hernia Patient is not sober Ventilation problems during induction of anaesthesia Gastric regurgitation during induction of anaesthesia Patient with a tracheostomy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Retromolar<br>Patients in whom the vocal cord visualisation starts with the retromolar method, which has been randomized determined preoperatively. The second visualization then will be performed with the conventional method. | Other: Retromolar Vocal Cord Visualisation<br>* For easier insertion of the laryngoscope the head of the patient will be turned to the left site. Thereafter the blade (Miller) will be inserted into the mouth and pushed carefully as far as possible laterally to receive a direct view of the vocal cords. Then the performing anesthesiologist determine the Cormack & Lehane score without and thereafter with a BURP (backward upward rightward pressure) maneuver.<br>Other: Conventional Vocal Cord Visualisation<br>* The head of the patient will be positioned as usual. After 2 minutes oxygen insufflation the laryngoscope will be inserted laterally to push the tongue to the left side in order to release the sight to the vocal cords. Thereafter the anesthesiologist determines the Cormack & Lehane score without and thereafter with performance of the BURP (backward upward rightward pressure) maneuver.<br>|
| Other: Convenvtional<br>Patients in whom the vocal cord visualisation starts with the conventional method, which has been randomized determined preoperatively. The second visualization then will be performed with the retromolar method. | Other: Retromolar Vocal Cord Visualisation<br>* For easier insertion of the laryngoscope the head of the patient will be turned to the left site. Thereafter the blade (Miller) will be inserted into the mouth and pushed carefully as far as possible laterally to receive a direct view of the vocal cords. Then the performing anesthesiologist determine the Cormack & Lehane score without and thereafter with a BURP (backward upward rightward pressure) maneuver.<br>Other: Conventional Vocal Cord Visualisation<br>* The head of the patient will be positioned as usual. After 2 minutes oxygen insufflation the laryngoscope will be inserted laterally to push the tongue to the left side in order to release the sight to the vocal cords. Thereafter the anesthesiologist determines the Cormack & Lehane score without and thereafter with performance of the BURP (backward upward rightward pressure) maneuver.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of vocal cord visualisation between the retromolar and the conventional method | In our present clinical trial we intend to compare the vocal cord visualisation by using the retromolar access compared to conventional intubation technique. Visualisation will be performed by randomized sequence and both methods will be performed in each patient. When no 100% visualisation of the vocal cords is achievable, a BURP (backward upward rightward pressure) manoeuvre will be performed. The same procedure will be performed for the another technique as well. For each trial, the anaesthesist has max. 30 seconds time for the vocal cord visualisation and scoring, which includes also the performance of the BURP-manoeuvre. Thereafter, and between each of the vocal cord visualizations as well, the patient will be ventilated by 100% oxygen for at least 20 seconds to reach at least 97% SpO2. Then intubation is performed in all patients by the conventional methode, and if intubation fails the retromolar technique, if possible. | After Intubation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Retromolar, Difficult Intubation