Do the Head-elevated Position and the Use of a Videolaryngoscope Facilitate Orotracheal Intubation in a Patient Population Without Predictable Difficulty of Intubation

Study Overview
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Brief Summary
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The main hypothesis of this study is that there is a synergy between the use of the HELP position and the use of a McGrath® Mac videolaryngoscope to facilitate tracheal intubation during anesthesia. The HELP position is the patient positioning on the AirPal RAMP, the two cushions inflated, bringing the external auditory canal to the same level as the sus-sternal notch.

Detailed Description
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Airway management remains an important determinant of morbidity and mortality in anesthesia, despite progress in recognizing factors of difficult mask ventilation and intubation. Many recommendations have been published regarding the practice of intubation in anesthesia. Our study focuses on two topics which remain under discussion: the position of the patient's head and the use of a videolaryngoscope. As to patient's head position, most anesthesiologists place the patient in the sniffing position (supine torso with neck flexed forward, and head extended), a position denominated sniffingby analogy to that adopted to smell a perfume. However, Adnet et al. questioned this position based on magnetic resonance imaging of eight healthy young volunteers positioned either with their heads in a neutral position or in extension, or with their heads and necks on a pillow. They showed that the sniffing position does not allow the alignment of the three important axes (mouth, pharynx and larynx) in awake patients with normal airway anatomy [1]. The Head Elevated Laryngoscopic position (HELP), with a raise of the head and neck so that An imaginary horizontal line should connect the patient's sternal notch with the external auditory meatus [2] facilitates the alignment of the pharyngeal, laryngeal, and oral axes of the airway during difficult laryngoscopy [3]. As to videolaryngoscopy, there is no doubt that it is a major advance in airway management. A recent Cochrane Systematic Review concluded that videolaryngoscopy increased easy laryngeal views and reduced difficult views and intubation difficulty [4]. However, its place is still debated: first line or rescue in case of suspected difficult airway. Its systematic use means discarding the standard Macintosh laryngoscope [5] which is not supported by clinical studies, in particular those of Wallace et al. [6] and of Thion et al. [7]. In the present randomized study we will study a combination of two factors in tracheal intubation on patients without suspected airways abnormalities: position (sniffing or HELP) and a McGrath laryngoscope (with or without video). This leads to four groups, A: sniffing position plus McGrath Mac videolaryngoscope with its screen deactivated so as to mimic a plain laryngoscope (R-V-), B: HELP plus McGrath Mac videolaryngoscope with a deactivated video screen (R+V-), C: sniffing position plus a McGrath Mac videolaryngoscope with an activated video screen (R-V+), D: HELP plus a McGrath Mac videolaryngoscope with it video screen activated (R+V+). This protocol allows using the same type of laryngoscope in all cases.

Official Title
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Do the Head-elevated Position and the Use of a Videolaryngoscope Facilitate Orotracheal Intubation in a Patient Population Without Predictable Difficulty of Intubation

Conditions
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Anesthesia

Intervention / Treatment
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* Device: Without RAMP and without video
* Device: With RAMP and with video
* Device: Without RAMP and with video
* Device: With RAMP and without video


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 18 - 89 years old Scheduled for elective surgical procedures Requiring oro-tracheal intubation for general anesthesia Having a telephone and agreeing to communicate their phone number in case of ambulatory surgery Having signed an informed consent form Benefiting from a social insurance Exclusion Criteria: Pregnant or breast-feeding women Patients with an anticipated difficult mask ventilation or an anticipated difficult intubation (Arné's score ≥ 11) Patients scheduled for a surgical procedure involving the mouth or the upper airway Patients requiring a rapid induction sequence, the use of a double-lumen tube Patients having a contra-indication to one of the drug administered by the protocol

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 89 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: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Without RAMP and without video<br>Sniffing position and a standard Macintosh laryngoscope | Device: Without RAMP and without video<br>* Intubation with video-laryngoscope McGrath without use of the video feature and patient positioning without RAMP device<br>|
| Experimental: With RAMP and with video<br>Ramped position and a McGrath Mac videolaryngoscope | Device: With RAMP and with video<br>* Intubation with video-laryngoscope McGrath with use of the video feature and patient positioning with RAMP device<br>|
| Experimental: Without RAMP and with video<br>Sniffing position and a McGrath Mac videolaryngoscope | Device: Without RAMP and with video<br>* Intubation with video-laryngoscope McGrath with use of the video feature and patient positioning without RAMP device<br>|
| Experimental: With RAMP and without video<br>Ramped position and a standard Macintosh laryngoscope | Device: With RAMP and without video<br>* Intubation with video-laryngoscope McGrath without use of the video feature and patient positioning with RAMP device<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of oro-tracheal intubations for which it is necessary to use the assistance of a third party required by the operator | Intubation is video and audio recorded. The number of people nedeed is determined from the audio/video recording a posteriori by two independent evaluators | 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to perform the intubation | Based on the video recording: from the passage the incisors to the third capnogram | 30 minutes | 
| First intubation succes rate | Defined by repositioning of the videolaryngoscope blade in the patient's mouth | 30 minutes | 
| Assessment of the Quality of visualization of the glottis | It is appreciated in real time by score of Cormak and Lehane modified by Yentis : from Grade 1 (glottis seen in totality) to Grade 4 (glottis hidden by epiglottis and tongue) | 30 minutes | 
| Assessment of the Percentage of the opening of the glottic orifice | It is appreciated in real time POGO (Percentage of Opening of the Glottic orifice) score : from 0% (opening not visible) to 100% (all of the opening is visible) | 30 minutes | 
| Assessment of quality of intubation with use of alternative techniques | Determined a posteriori from the video recording analysis | 30 minutes | 
| Occurrence of esophageal intubation | Reported in real time by the operator during the video / audio recording | 30 minutes | 
| Number of tracheal intubation failure | Number of tracheal intubation failure reported by the operator during the video / audio recording. Can be determined a posteriori from the video / audio recording. | 30 minutes | 
| Incidence of arterial oxygen desaturation (SpO2 < 92%) | Valued in real time and reported by the operator during the video / audio recording. | 30 minutes | 
| Perception of difficulty in intubation | Evaluation in real time based on a scale betwwen zero ( no difficulty) to ten (extremely difficult) | 30 minutes | 
| Cooperation of the various members of the anesthesia team | Determined from the video / audio recording using Kraus Scale to evaluate cooperation and non-cooperation behaviors within the team. Positive rating: scale from 0 (never reported by the obsever) to 4 (obvious to the obsever). Negative rating: scale from 0 (nerver reported by the observer) to 4 (obvious most of the time for the observer) | 30 minutes | 
| Evolution of Blood pressure | Blood pressure is monitored before the induction, before and after intubation. | 30 minutes | 
| Evolution of Heart beat | Heart beat is monitored before the induction, before and after intubation. | 30 minutes | 
| Evaluation of frequency of intubation complications | Number of events of Sore throat and voice change evaluated during postoperative visit on day 1 of the surgery | 24 hours | 
| Evaluation of severity of intubation complications | Severity is evaluated during postoperative visit on day 1 of the surgery with 2 questions to the patient about his/her sore throat and voice change | 24 hours |