McGRATH MAC Video Laryngoscope

Study Overview
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Brief Summary
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This study was designed to determine the first attempt success rate of tracheal intubation with the McGRATH™ MAC laryngoscope using direct visualization in patients with known difficult airways, as well as exploring the possibility of identifying a particular direct Cormack-Lehane (C-L) grade view where indirect (video) visualization can be most beneficial during laryngoscopy and intubation.

Official Title
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McGRATH MAC Video Laryngoscope - To View or Not To View?

Conditions
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Intubation; Difficult

Intervention / Treatment
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* Device: McGrath MAC enhanced direct laryngoscope


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI < 50 kg/m2 Two or more of the following inclusion criteria: Mallampati class: III-IV; Reduced mouth opening < 4 cm; Neck circumference > 40 cm for females and > 43 cm for males; Thyromental distance < 6 cm; Ratio of the patient's height to thyromental distance ≥ 23.5; Sternomental distance < 12 cm Exclusion Criteria: BMI ≥ 50 kg/m2 emergency status cervical injury or pathology neck irradiation known difficult airway risk of gastric aspiration hemodynamic instability requiring rapid sequence intubation

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

Primary Purpose: Supportive Care
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: McGrath Mac intubations<br>All 100 patients will be intubated using the McGRATH® MAC video laryngoscope, either through direct or indirect vision laryngoscopy. The liquid crystal display (LCD) monitor of the McGRATH™ MAC was initially covered; if the anesthesiologist visualized a modified C-L grade 1-3 view, the patient was intubated utilizing this direct view. If the anesthesiologist observed a modified C-L grade 4 view during their initial direct view, the patient was intubated using the indirect method. If intubation via direct laryngoscopy was unsuccessful on the first attempt, the patient was intubated using the indirect view. If both methods of laryngoscopy were unsuccessful, the rescue intubation technique was performed at the discretion of the anesthesiologist. | Device: McGrath MAC enhanced direct laryngoscope<br>* The McGRATH® MAC enhanced direct laryngoscope (EDL) combines the familiarity of direct laryngoscopy with an inline video camera for an enhanced view. All 100 patients will be intubated using the McGRATH® MAC video laryngoscope, either through direct or indirect vision laryngoscopy. The LCD monitor of the McGRATH™ MAC was initially covered; if the anesthesiologist visualized a modified C-L grade 1-3 view, the patient was intubated utilizing this direct view. If the anesthesiologist observed a modified C-L grade 4 view during their initial direct view, the patient was intubated using the indirect method. If intubation via direct laryngoscopy was unsuccessful on the first attempt, the patient was intubated using the indirect view. If both methods of laryngoscopy were unsuccessful, the rescue intubation technique was performed at the discretion of the anesthesiologist.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants Successfully Intubated on First Attempt With Use of Either a Direct or Indirect Laryngoscopic View | All 100 patients will be intubated using the McGRATH® MAC video laryngoscope, either through direct or indirect vision laryngoscopy. The LCD monitor of the McGRATH™ MAC was initially covered; if the anesthesiologist visualized a modified C-L grade 1-3 view, the patient was intubated utilizing this direct view. If the anesthesiologist observed a modified C-L grade 4 view during their initial direct view, the patient was intubated using the indirect method. If intubation via direct laryngoscopy was unsuccessful on the first attempt, the patient was intubated using the indirect view. If both methods of laryngoscopy were unsuccessful, the rescue intubation technique was performed at the discretion of the anesthesiologist. | after successful endotracheal tube placement | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glottic View With Direct Laryngoscopy | Glottic view as described by Cormack and Lehane, scored as follows- Grade 1. Full view of glottis Grade 2a. Partial view of glottis Grade 2b. Arytenoids or posterior portion of cords just visible Grade 3. Only the epiglottis visible Grade 4. Neither epiglottis nor glottis visible | at the time of laryngoscopy | 
| Glottic View With Indirect Laryngoscopy | Glottic view as described by Cormack and Lehane (Samsoon GL, Young JR. Difficult tracheal intubation: A retrospective study. Anesthesia 1987; 42:487), scored as follows- Grade 1. Full view of glottis Grade 2a. Partial view of glottis Grade 2b. Arytenoids or posterior portion of cords just visible Grade 3. Only the epiglottis visible Grade 4. Neither epiglottis nor glottis visible | at the time of laryngoscopy | 
| Time for Direct View Laryngoscopy During the First Attempt | Time from mouth opening to best direct laryngoscopic view | at the time of laryngoscopy | 
| Time for Indirect View Laryngoscopy During the First Attempt | Time from mouth opening to best indirect laryngoscopic view | at the time of laryngoscopy | 
| Time for Intubation | Time for laryngoscopy (either direct or indirect) plus the time for endotracheal tube (ETT) cuff to pass vocal cords. | at the time of laryngoscopy | 
| Number of Intubation Attempts |  | at the time of intubation | 
| Number of Participants Who Received External Laryngeal Manipulation During the First Attempt |  | at the time of intubation | 
| Number of Participants on Whom Bougie (Introducer) Was Used to Facilitate Intubation on the First Attempt |  | at the time of intubation | 
| Subjective Ease of Laryngoscopy | The anesthesiologists rated the McGRATH™ MAC's ability in managing airways as very easy, easy, slight resistance, difficult, or not possible. The difficulty of laryngoscopy was evaluated during the insertion and placement of the McGRATH™ MAC, from the patient's lips, into their oropharynx, until a glottic view was obtained. | at the time of laryngoscopy | 
| Subjective Ease of Intubation | The anesthesiologists rated the McGRATH™ MAC's ability in managing airways as very easy, easy, slight resistance, difficult, or not possible. The difficulty of endotracheal tube (ETT) delivery (that is, intubation) was evaluated during the insertion of the ETT into the patient's mouth, until the ETT passed the vocal cords. | at the time of laryngoscopy | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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BMI < 50 kg/m2, Mallampatti class: III-IV, Reduced mouth opening < 4 cm, Neck circumference > 40 cm for females and > 43 cm for males, Thyromental distance < 6 cm, Ratio of the patient's height to thyromental distance ≥ 23.5, Sternomental distance < 12 cm