Evaluation of the Rapid Airway Management Positioner

Not Applicable

Completed

Conditions: Rapid Airway Management Positioner
Endotracheal Intubation

Interventions: Device: Laryngoscopy without RAMP
Device: Laryngoscopy with RAMP

Registration Number: NCT00581230

Lead Sponsor: The University of Texas Health Science Center, Houston

Brief Summary: The purpose of this study is to determine if the Rapid Airway Management Positioner (RAMP, AirPal, Center Valley, PA) is a useful positioning device for direct laryngoscopy and tracheal intubation in obese patients undergoing gastric bypass or laparoscopic gastric banding surgery.

Detailed Description: The cannot intubate, cannot ventilate case is the most dangerous of situations, and being able to foresee, prevent, and prepare for such difficulties is the task of every anesthesiologist. Difficult mask ventilation is predicted by a number of factors, including obesity.1 Appropriate bag-and-mask ventilation necessitates a patent airway. An increased BMI is associated with a reduced posterior airway space behind the tongue's base as well as a quick development of hypoxemia from reduced functional residual capacity in improper mask ventilation.1 Proper head and neck positioning to establish the patent airway then is especially important.

There is an increased risk of difficult laryngoscopy among obese patients compared with subjects with normal body mass index.2,3 Optimal laryngeal view during laryngoscopy can be facilitated with proper head and neck positioning, including slight elevation of the head, neck flexion relative to the chest, and extreme atlanto-occipital extension.4 The "ramped" position, where the patient's ear is horizontally aligned with their sternal notch, has been found to be superior to the standard "sniffing" position, 7-cm occiput elevation, during direct laryngoscopy in morbidly obese patients.4

Additionally, there are increased difficulties and risks for tracheal intubation in obese patients versus normal-weight patients. Studies have found that chances for a successful first attempt at oral intubation decrease as patient weight increases.6,7 Improving visualization of laryngeal structures will increase the likelihood of successful tracheal intubation, as increasing the percentage of glottic opening is correlated with the number of intubation attempts, as well as the need for rescue intubation devices.8

It is estimated that endotracheal intubation is performed on approximately 8 million patients per year in the United States. Of these endotracheal intubations, approximately 80% are performed by direct laryngoscopy with transoral placement of the endotracheal tube (ET) into the trachea. There is fairly uniform reporting of the incidence of failed intubation in the literature; it occurs in approximately 0.05% or 1:2230 of surgical patients and in approximately 0.13% to 0.35%, or 1:750 to 1:280, of the obstetric patients.9,10 The incidence of unsuspected difficult intubation is estimated to be higher at 3%. One factor that contributes to difficult intubation is poor visualization, and difficult laryngoscopy is highly correlated with poor laryngeal exposure.11

The Rapid Airway Management Positioner (RAMP) is designed to optimize visualization during direct laryngoscopy by placing the patient into the proper head-elevated laryngoscopy position (HELP). In morbidly obese patients, achieving this position is important,12 and requires a great deal of support under the head and shoulders that could not be performed singlehandedly.13 The RAMP is an easy-to-use, quick device, taking an average of 56 seconds to place and inflate.14

The RAMP has great potential in obese patients. Pre-positioning also helps increase the desaturation safety period for morbidly obese patients.15 Rescue ventilation techniques are facilitated by the HELP position, when the head and neck are elevated above the chest and abdomen. The airway is therefore more isolated and easier to work with, and less positive airway pressure is needed when the weight of the abdomen is away from the diaphragm. Currently, placing a patient on top of stacked blankets is common and can create the HELP, or "ramped" position, 5 but also causes variable and unstable results. We suspect that by providing a better laryngeal view, the RAMP may help decrease the incidence of tissue trauma associated with intubation, and intubation may be achieved more quickly in a population that is known to be difficult.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 51

Inclusion Criteria

The 50 subjects will be adult surgical candidates age 18-80, ASA I-III, BMI > 30 kg/m2 presenting for gastric bypass or laparoscopic gastric banding surgery who require general anesthesia.

Exclusion Criteria

Patients will be excluded if it is determined that an awake intubation should be performed. Mallampati IV and ASA IV-V patients will also be excluded, as well as patients with unstable cervical, thoracic and/or lumbar fracture.

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Laryngoscopy without RAMP	Laryngoscopy without RAMP	First, laryngoscopy will be preformed utilizing a traditional Macintosh size 4 blade laryngoscope. The view of the laryngeal aperture will be recorded, and a photo will be taken by the Airway Cam™.
Laryngoscopy with RAMP	Laryngoscopy with RAMP	Next, the Rapid Airway Management Positioner (RAMP) will be positioned and inflated underneath the patient so that the patient is placed in the optimal sniffing position. The investigator will again perform laryngoscopy utilizing the same technique and the laryngeal view will be recorded.

Primary Outcome Measures

Name	Time	Method
Ease of Mask Ventilation as Assessed by Han Class	Time before intubation	Grading Scale for Mask Ventilation as described by Han et al. (Anesthesiology. 2004 Jul;101(1):267) Grade 0. Ventilation by mask not attempted Grade 1. Ventilated by mask Grade 2. Ventilated by mask with oral airway/adjuvant with or without muscle relaxant Grade 3. Difficult ventilation (inadequate, unstable, or requiring two providers) with or without muscle relaxant Grade 4. Unable to mask ventilate with or without muscle relaxant
Glottic View as Assessed by the Cormack and Lehane Classification	before intubation	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

Secondary Outcome Measures