Airway Complication of Anaesthesia
Conditions
Brief summary
A laryngoscope is a medical instrument that is used to get a view of the voice box and the space in between the vocal cords. A laryngoscope is used to place a breathing tube into the trachea (windpipe or airway) to protect the patient's airway and provide a way to help a person breathe during surgery; this is called intubation.
Detailed description
A laryngoscope is a medical instrument that is used to get a view of the voice box and the space in between the vocal cords. A laryngoscope is used to place a breathing tube into the trachea (windpipe or airway) to protect the patient's airway and provide a way to help a person breathe during surgery; this is called intubation. The placement of a breathing tube into the windpipe is a skill that is not easily mastered. In fact, the placement is difficult or impossible using the usual technique in 1-3 of every 100 patients. The ease of placing this breathing tube depends in part on how easily and how much of the vocal cords are able to be seen directly using a laryngoscope. In a small number of patients, the Levitan First Pass Success (FPS) Scope has been shown to be more effective and easier to insert even in patients who have difficult airways. This study will evaluate the use of the LFS compared to the other conventional laryngoscope in subjects with a simulated difficult airway. The goal of this study is to determine the effectiveness and safety of the LFS in a large number of patients with simulated airway difficulties. The results obtained during the study may provide useful information to health care providers who cannot place a breathing tube in patients that are either in operating rooms or in emergency situations requiring intubation by paramedics. An example would be a trauma situation where a paramedic is having difficulty attempting an intubation when a patients c-spine is being protected from any movements. The LFS is an affordable and transportable device, which makes this an attractive asset for health providers in smaller community settings or in paramedic vehicles which may not have the capacity to stock or ability to afford a variety of different scopes and must choose a more limited selection.
Interventions
DEVICELaryngoscopy order: 1) MAC, 2) Levitan
Laryngoscopy with MAC, then Levitan
DEVICELaryngoscopy order: 1) Levitan, 2) MAC
Laryngoscopy with Levitan, then MAC
Sponsors
IWK Health Centre
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
FEMALE
Age
16 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
1. American Society of Anesthesiologists (ASA) physical status I or II (healthy or mild systemic disease, ex. asthma, high blood pressure) 2. Elective surgery requiring endotracheal intubation 3. English speaking 4. Age 16 - 75 years
Exclusion criteria
1. Significant gastroesophageal reflux disease (GERD) that may require alternate induction/intubation techniques 2. Prior history of a difficult intubation requiring an awake tracheal intubation 3. Clinical predictors of a potentially difficult intubation requiring an awake intubation 4. BMI \> 45 kg/m2 (Obesity is a common and important risk factor for difficult intubation)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cormack-Lehane Grade | intraoperative | The anesthesiologist graded the laryngeal view after induction of anesthesia using Cormack-Lehane Scale. Grade 1 = full view of glottis Grade 2a = partial view of glottis Grade 2b = Only posterior extremity of glottis seen or only arytenoid cartilages Grade 3 = Only epiglottis seen, none of glottis seen Grade 4 = Neither glottis nor epiglottis seen |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of Intubation Attempts | intraoperative | Number of intubation attempts was recorded after intubation was completed. |
| Operator Rating of Difficulty | intraoperative | The attending anesthesiologist rated the difficulty in using each technique to intubate the larynx using an 11-point numeric rating scale and a 4-point visual rating scale. |
| Time to Successful Intubation | intraoperative | Time to successful intubation was documented during the second laryngoscopy and defined as the time from the insertion of the Macintosh laryngoscope into the oral cavity to its removal. |
Participant flow
Recruitment details
From July 29,2009 to March 12, 2010 we recruited women aged 16-75 yrs old, ASA class I-II, and undergoing elective gynecologic surgery at the IWK Health Centre under general anesthesia with planned orotracheal intubation.
Pre-assignment details
105 participants were consented and randomized, and of those 11 were withdrawn for either anticipated difficult airway, decreased SpO2, or unavailable staff/equipment. A total of 94 participants started the study protocol. 3 were withdrawn. 91 participants completed the study protocol.
Participants by arm
| Arm | Count |
|---|---|
| Intubation Order Levitan/MAC The LFS is used to guide and confirm endotracheal placement of endotracheal tubes during routine laryngoscopy. | 49 |
| Intubation Order MAC/Levitan A size 7.0-mm endotracheal tube with a malleable stylet was used to facilitate Macintosh intubation (standard practice). | 45 |
| Total | 94 |
Baseline characteristics
| Characteristic | Intubation Order Levitan/MAC | Intubation Order MAC/Levitan | Total |
|---|---|---|---|
| Age, Customized | 45 years STANDARD_DEVIATION 13 | 45 years STANDARD_DEVIATION 13 | 45 years STANDARD_DEVIATION 13 |
| Sex: Female, Male Female | 49 Participants | 45 Participants | 94 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 91 | 0 / 94 |
| serious Total, serious adverse events | 0 / 91 | 0 / 94 |
Outcome results
Primary
Cormack-Lehane Grade
The anesthesiologist graded the laryngeal view after induction of anesthesia using Cormack-Lehane Scale. Grade 1 = full view of glottis Grade 2a = partial view of glottis Grade 2b = Only posterior extremity of glottis seen or only arytenoid cartilages Grade 3 = Only epiglottis seen, none of glottis seen Grade 4 = Neither glottis nor epiglottis seen
Time frame: intraoperative
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Levitan/MAC Intubation | Cormack-Lehane Grade | Good Laryngoscopic View-Cormack-Lehane grade 1 & 2 | 58 participants |
| Levitan/MAC Intubation | Cormack-Lehane Grade | Poor Laryngoscopic View-Cormack-Lehane grade 3 & 4 | 33 participants |
| MAC/Levitan Intubation | Cormack-Lehane Grade | Good Laryngoscopic View-Cormack-Lehane grade 1 & 2 | 53 participants |
| MAC/Levitan Intubation | Cormack-Lehane Grade | Poor Laryngoscopic View-Cormack-Lehane grade 3 & 4 | 41 participants |
Secondary
Number of Intubation Attempts
Number of intubation attempts was recorded after intubation was completed.
Time frame: intraoperative
Secondary
Operator Rating of Difficulty
The attending anesthesiologist rated the difficulty in using each technique to intubate the larynx using an 11-point numeric rating scale and a 4-point visual rating scale.
Time frame: intraoperative
Secondary
Time to Successful Intubation
Time to successful intubation was documented during the second laryngoscopy and defined as the time from the insertion of the Macintosh laryngoscope into the oral cavity to its removal.
Time frame: intraoperative