Abstract
Study objective
There is growing use of video laryngoscopy in US emergency departments (EDs). This study seeks to compare intubation success between the GlideScope video laryngoscope and the C-MAC video laryngoscope (C-MAC) in ED intubations.
Methods
This was an analysis of quality improvement data collected during a 3-year period in an academic ED. After each intubation, the operator completed a standardized data form reporting patient demographics, indication for intubation, device(s) used, reason for device selection, difficult airway characteristics, number of attempts, and outcome of each attempt. An attempt was defined as insertion of the device into the mouth regardless of attempt at tube placement. The primary outcomes were first pass and overall intubation success. The study compared success rates between the GlideScope video laryngoscope and the C-MAC groups, using multivariable logistic regression and adjusting for potential confounders.
Results
During the 3-year study period, there were 463 intubations, including 230 with the GlideScope video laryngoscope as the initial device and 233 with the C-MAC as the initial device. The GlideScope video laryngoscope resulted in first-pass success in 189 of 230 intubations (82.2%; 95% confidence interval [CI] 76.6% to 86.9%) and overall success in 221 of 230 intubations (96.1%; 95% CI 92.7% to 98.2%). The C-MAC resulted in first-pass success in 196 of 233 intubations (84.1%; 95% CI 78.8% to 88.6%) and overall success in 225 of 233 intubations (96.6%; 95% CI 93.4% to 98.5%). In a multivariate logistic regression analysis, the type of video laryngoscopic device was not associated with first-pass (odds ratio 1.1; 95% CI 0.6 to 2.1) or overall success (odds ratio 1.2; 95% CI 0.5 to 3.1).
Conclusion
In this study of video laryngoscopy in the ED, the GlideScope video laryngoscope and the C-MAC were associated with similar rates of intubation success.
Introduction
Background
Direct laryngoscopy is the traditional technique for tracheal intubation in the emergency department (ED). However, it requires alignment of the pharyngeal, laryngeal, and tracheal axes, which can often be difficult or impossible in select patients. In the last decade, video laryngoscopes have been introduced into clinical practice and have been used with increasing frequency for ED intubations.1-6 Unlike direct laryngoscopy, video laryngoscopes incorporate a video camera on the undersurface of the blade and transmit the image to a video monitor. This design allows the operator to indirectly view and intubate the glottis, without a direct view of laryngeal structures. Although several different video laryngoscopes are commercially available, the GlideScope (Verathon Medical, Bothell, WA) and the C-MAC (Karl Storz, Tuttlingen, Germany) are the most widely used in US EDs.
Importance
The GlideScope video laryngoscope and the C-MAC have key design differences, and thus slightly different technique may be needed to achieve glottic exposure. The C-MAC has a blade shaped much like a standard Macintosh curve, allowing for a conventional approach similar to direct laryngoscopy. In contrast, the GlideScope video laryngoscope blade has a 60-degree curvature. Although the hyperangulated curvature affords improved glottic exposure in difficult airways, it also requires use of a specially designed curved rigid stylet (GlideRite stylet) to facilitate direction of the tracheal tube to the laryngeal inlet. Given these design differences, it is unclear whether either device would result in higher tracheal intubation success in ED patients. Several studies have compared the GlideScope video laryngoscope and C-MAC to direct laryngoscopyo7-32 but no study has directly compared the GlideScope video laryngoscope with C-MAC in the ED, to our knowledge.
Goals of This Investigation
The goal of this investigation was to compare intubation success between GlideScope video laryngoscope and C-MAC laryngoscopy in ED patients at an urban academic university hospital.
Materials and Methods
Study Design
We analyzed quality improvement data prospectively collected during a 3-year period from February 1, 2009, to January 31, 2012. This project was granted exemption by the University of Arizona Institutional Review Board.
Setting
This study was conducted at the University of Arizona Medical Center, which has a 61-bed tertiary care academic ED with an annual census of approximately 70,000 visits. This ED, also a Level I trauma center, has an ACGME-accredited 3-year emergency medicine residency program, as well as a 5-year combined pediatric/emergency medicine residency program. The majority of intubations in our ED are performed by emergency medicine residents under emergency medicine attending physician supervision.
Selection of Participants
The GlideScope video laryngoscope and the C-MAC were introduced to our ED in 2001 and 2009, respectively. Only patients who were intubated according to the GlideScope video laryngoscope or the C-MAC as the initial device from February 2009 until January 2012, when both devices were available in the ED, were included in this study. To allow a fair comparison of devices in this study, only intubations performed with the standard reusable GlideScope video laryngoscope were included in this analysis. Also, only intubations using the manufacturer-recommended stylet (GlideRite Rigid Stylet for the GlideScope video laryngoscope and standard malleable stylet for the C-MAC) were included in the study. Device selection and blade size were based on provider preference. Before starting their emergency medicine residency, residents reported variable experience with the GlideScope video laryngoscope, and no resident had experience with the C-MAC.
Data Collection and Processing
After each intubation, the operator completed a standard data collection form describing patient demographics, operator specialty, operator level (postgraduate year), indication for intubation, method of intubation, paralytic agent, sedative agent, device(s) used, reason for device selection, presence of certain difficult airway characteristics, number of attempts at intubation, and the outcome of each attempt. Methods of intubation included rapid sequence intubation, oral intubation with a sedative agent only, and oral intubation without medications.
Reasons for selection of video laryngoscope intubation were defined as “standard,” “difficult,” and “education.” “Standard” indicated routine airway management with no anticipated difficulty. “Difficult” included airways with identified difficult anatomic features. “Education” included instances in which the operator used the device to gain educational experience.
Standard preoperative difficult airway predictors such as the Mallampati score, thyromental distance, and neck mobility have been shown to be challenging to apply in the emergency setting because of lack of patient cooperation and the urgency to complete the intubation rapidly.33,34 Thus, we developed a list of difficult airway characteristics that were feasible for determination before intubation, including cervical immobility (intrinsic or caused by a cervical collar), obesity, large tongue, short neck, small mandible, facial or neck trauma, airway edema, blood in the airway, and vomit in the airway.
The senior author reviewed the data forms. If the form had any missing data, it was returned to the operator for completion. If information on the form contained inconsistencies, the operator was interviewed by the senior author for clarification. The data forms were cross-referenced to professional billing and pharmacy records to identify any intubations performed without a corresponding data form. If an intubation was identified without a data form, the operator was given a data form to complete as soon as possible to ensure a maximal capture rate.
Outcome Measures
The primary outcomes were first-pass success and overall intubation success. First-pass success was defined as successful intubation on the initial attempt. Overall intubation success was defined as successful intubation with the initial device regardless of number of attempts required. An attempt was defined as insertion of the laryngoscope blade into the oropharynx regardless of whether an attempt was made to pass the endotracheal tube. Successful intubation was defined as correct placement of the endotracheal tube in the trachea, as confirmed by end-tidal CO2 capnometry, pulse oximetry, chest auscultation, observation of chest excursion, absence of epigastric sounds, and misting of the endotracheal tube. If there was uncertainty about endotracheal tube placement by the operator and the tube was removed and replaced, the attempt was classified as an esophageal intubation.
According to a previous study using a similar design,35 confounders included in the multivariable analysis were age, sex, trauma status, indication for intubation, method of intubation, paralytic agent, induction agent, presence of at least 1 difficult airway characteristic, operator specialty, Emergency Medicine Resident (EMR) level, and operator-specified reason for device selection.
Primary Data Analysis
Summary statistics were generated for patient, intubation, and operator characteristics. Continuous normally distributed variables were compared between the C-MAC and GlideScope video laryngoscope groups with a Student's t test. Categorical variables were compared between groups with the Fisher's exact test. Multivariate logistic regression analyses were performed for each of the outcome variables: first-pass success and overall success. The predictor variable of interest was intubation device (GlideScope video laryngoscope or C-MAC). Other predictor variables added to each model to adjust for confounding included age, sex, trauma status, indication for intubation, method of intubation, paralytic agent, induction agent, presence of at least 1 difficult airway characteristic, operator specialty, EMR level, and operator-specified reason for device selection.
The data were entered into the electronic database program HanDBase 4.0 for the iPad (DDH Software, Wellington, FL; http://www.ddhsoftware.com) and subsequently transferred to Excel for Windows 2010 (Microsoft, Redmond, WA; http://www.microsoftstore.com). Summary statistics were calculated with InStat 3.10 for Windows (GraphPad Software, San Diego, CA; http://www.graphpad.com). All other statistical analyses were performed with Stata for Windows (version 12; StataCorp, College Station, TX; http://www.stata.com).
Results
During the 3-year study period, a total of 1,475 consecutive intubations were performed in the ED. We excluded 782 performed with direct laryngoscopy or devices other than GlideScope video laryngoscope or C-MAC, 182 GlideScope video laryngoscope procedures using a standard stylet, 26 procedures performed by nonemergency physicians, and 22 patients younger than 18 years. We included the remaining 463 GlideScope video laryngoscope or C-MAC intubations in the analysis. Baseline patient, intubation, and operator characteristics are listed in Table 1. A total of 91 providers performed 413 of the intubations. The providers for the remaining 50 intubations were not known. The median number of intubations performed per provider was 4 (interquartile range 2 to 5).
Table 1.
Patient, intubation, and operator characteristics.
| Characteristics | N (%; 95% CI) | |
|---|---|---|
|
| ||
| GVL (n=230) | C-MAC (n=233) | |
| Patient characteristics | ||
| Mean age, y* | 47.7; 45.2 to 50.2 | 49.6; 47.1 to 52.1 |
| Sex | ||
| Male | 155 (67.4; 61.3 to 73.5) | 152 (65.2; 59.1 to 71.4) |
| Medical/trauma | ||
| Trauma patients | 137 (59.6; 53.2 to 66.0) | 98 (42.1; 35.7 to 48.5) |
| DACs | ||
| 1 or more | 179 (77.8; 72.4 to 83.2) | 146 (62.7; 56.4 to 68.9) |
| Intubation characteristics | ||
| Primary reason for intubation | ||
| Airway protection | 150 (65.2; 59.0 to 71.4) | 131 (56.2; 49.8 to 62.6) |
| Respiratory failure | 27 (11.7; 7.5 to 15.9) | 43 (18.5; 13.4 to 23.5) |
| Cardiac arrest | 30 (13.0; 8.7 to 17.4) | 32 (13.7; 9.3 to 18.2) |
| Patient control | 19 (8.3; 4.7 to 11.9) | 22 (9.4; 5.7 to 13.2) |
| Hypoxia | 4 (1.7; 0.0 to 3.4) | 5 (2.2; 0.3 to 4.0) |
| Reason for device | ||
| Standard | 48 (20.7; 15.6 to 26.2) | 63 (27.0; 21.3 to 32.8) |
| Difficult | 153 (66.5; 60.4 to 72.7) | 86 (36.9; 30.7 to 43.2) |
| Education | 29 (12.6; 8.3 to 16.9) | 84 (36.1; 29.8 to 42.3) |
| Method of intubation | ||
| Rapid sequence intubation | 190 (82.6; 77.7 to 87.5) | 194 (83.3; 78.4 to 88.1) |
| No meds | 32 (13.9; 9.4 to 18.4) | 34 (14.6; 10.0 to 19.2) |
| Sedation only | 8 (3.5; 1.1 to 5.9) | 5 (2.1; 0.3 to 4.0) |
| Paralytic used | ||
| None | 40 (17.4; 12.5 to 22.3) | 39 (16.7; 11.9 to 21.6) |
| Rocuronium | 83 (36.1; 29.8 to 42.3) | 96 (41.2; 34.8 to 47.6) |
| Succinylcholine | 107 (46.5; 40.0 to 53.0) | 98 (42.1; 35.7 to 48.5) |
| Sedative used | ||
| None | 35 (15.2; 10.5 to 19.9) | 37 (15.9; 11.2 to 20.6) |
| Etomidate | 175 (76.1; 70.5 to 81.6) | 159 (68.2; 62.2 to 74.3) |
| Ketamine | 12 (5.2; 2.3 to 8.1) | 27 (11.6; 7.4 to 15.7) |
| Propofol | 7 (3.0; 0.8 to 5.3) | 9 (3.9; 1.4 to 6.4) |
| Other | 1 (0.4; −0.4 to 1.3) | 1 (0.4; −0.4 to 1.3) |
| Operator characteristics | ||
| Operator PGY | ||
| EMR 1 | 53 (23.0; 17.6 to 28.5) | 61 (26.2; 20.5 to 31.9) |
| EMR 2 | 98 (42.6; 36.2 to 49.1) | 90 (38.6; 32.3 to 44.9) |
| EMR 3 or attending | 79 (34.4; 28.2 to 40.5) | 82 (35.2; 29.0 to 41.4) |
DACs, Difficulty awareness characteristics; GVL, GlideScope video laryngoscope; PGY, postgraduate year.
Continuous variable.
Of the study population, 230 intubations were performed with the GlideScope video laryngoscope as the initial device and 233 with the C-MAC as the initial device. There were no baseline differences between groups, with the exception of trauma status, reason for device selection, and presence of 1 or more difficult airway characteristics (Table 1). There were 108 intubations in which the C-MAC was used exclusively as a video laryngoscope device, 77 intubations in which the C-MAC was used as a direct laryngoscopy, 44 intubations in which the C-MAC was initially used as direct laryngoscopy and switched to video laryngoscope in any attempt, and 4 intubations in which the C-MAC was initially used as video laryngoscope and switched to direct laryngoscopy. These were included in the analysis as C-MAC intubations.
There was no difference in unadjusted first-pass intubation success rates between the GlideScope video laryngoscope (82%) and C-MAC (84%) groups (odds ratio [OR] 0.87; 95% confidence interval [CI] 0.54 to 1.42). First-pass success was similar between the GlideScope video laryngoscope and the C-MAC when stratified by subgroups (Table 2) and was also similar between the GlideScope video laryngoscope and the C-MAC after adjustment for important confounders (OR 1.14; 95% CI 0.65 to 2.03).
Table 2.
Intubation success stratified by patient, intubation, and operator characteristics.
| Characteristics | First-Pass Success | Overall Success | ||||
|---|---|---|---|---|---|---|
|
|
|
|||||
| GVL, % | C-MAC, % | OR (95% CI)* | GVL, % | C-MAC, % | OR (95% CI)* | |
| Sex | ||||||
| Male | 80 | 81 | 0.5 (0.3–1.0) | 96 | 96 | 0.8 (0.3–2.4) |
| Female | 87 | 90 | [Reference] | 96 | 98 | [Reference] |
| Trauma status | ||||||
| Trauma | 81 | 81 | 0.7 (0.4–1.2) | 95 | 96 | 0.6 (0.2–1.5) |
| Nontrauma | 84 | 87 | [Reference] | 98 | 97 | [Reference] |
| Number of DACs | ||||||
| 0 | 90 | 94 | [Reference] | 98 | 99 | [Reference] |
| 1 | 91 | 85 | 0.6 (0.2–1.3) | 100 | 96 | 0.6 (0.1–3.8) |
| 2 | 74 | 80 | 0.3 (0.1–0.6) | 91 | 98 | 0.2 (0–1.2) |
| 3 or more | 74 | 64 | 0.2 (0.1–0.4) | 95 | 92 | 0.2 (0.1–1.1) |
| Reason for intubation | ||||||
| Airway protection | 84 | 89 | [Reference] | 96 | 99 | [Reference] |
| Respiratory failure | 93 | 88 | 1.5 (0.6–3.4) | 96 | 100 | 2.0 (0.3–16.4) |
| Cardiac arrest | 57 | 59 | 0.2 (0.1–0.4) | 93 | 84 | 0.2 (0.1–0.7) |
| Patient control | 90 | 86 | 1.2 (0.4–3.1) | 100 | 100 | N/A† |
| Hypoxia | 100 | 80 | 1.3 (0.2–10.6) | 100 | 80 | 0.2 (0–2.1) |
| Reason for device | ||||||
| Standard | 90 | 92 | [Reference] | 98 | 98 | [Reference] |
| Difficult | 78 | 74 | 0.3 (0.2–0.7) | 95 | 94 | 0.3 (0.1–1.4) |
| Education | 93 | 88 | 0.8 (0.3–2.0) | 100 | 98 | 1.0 (0.1–7.4) |
| Operator PGY | ||||||
| EMR 1 | 74 | 75 | [Reference] | 96 | 975 | [Reference] |
| EMR 2 | 84 | 90 | 2.2 (1.2–4.0) | 98 | 98 | 1.7 (0.4–6.8) |
| EMR 3 or attending | 86 | 84 | 2.0 (1.1–3.6) | 94 | 95 | 0.6 (0.2–2.0) |
| Paralytic used | ||||||
| None | 65 | 64 | [Reference] | 93 | 87 | [Reference] |
| Rocuronium | 89 | 88 | 4.1 (2.2–7.9) | 98 | 99 | 6.6 (1.7–25.6) |
| Succinylcholine | 83 | 89 | 3.3 (1.8–6.1) | 96 | 98 | 3.7 (1.3–11.1) |
| Sedative used | ||||||
| None | 66 | 65 | [Reference] | 91 | 87 | [Reference] |
| Etomidate | 85 | 88 | 3.4 (1.9–6.1) | 97 | 98 | 4.5 (1.7–12.1) |
| Ketamine | 83 | 85 | 2.9 (1.1–7.9) | 100 | 100 | N/A† |
| Propofol | 100 | 89 | 8.0 (1.0–64.0) | 100 | 100 | N/A† |
| Other | N/A | 100 | 0.5 (0–8.9) | 100 | 100 | N/A† |
Univariate analysis.
Dropped because it predicted success perfectly.
Overall intubation success was similar between the GlideScope video laryngoscope (96%) and the C-MAC (97%) (unadjusted OR 0.87; 95% CI 0.33 to 2.30). Overall success was similar between the GlideScope video laryngoscope and the C-MAC when stratified by subgroups (Table 2). Overall success was also similar between GlideScope video laryngoscope and C-MAC after adjustment for important confounders (OR 1.19; 95% CI 0.39 to 3.63). See Appendix E1 (available online at http://www.annemergmed.com) for multivariate logistic regression.
The median number of attempts was 1 (interquartile range 1 to 1; range 1 to 5). Among 8 C-MACs not achieving overall success, rescue intubation was accomplished by direct laryngoscopy (n = 6), GlideScope video laryngoscope (n=1), and cricothyrotomy (n= 1). Among 9 GlideScope video laryngoscope patients not achieving overall success, rescue intubation was accomplished by direct laryngoscopy (n = 6), cricothyrotomy (n=2), and C-MAC (n=1).
Limitations
This was a single-center study in an academic tertiary care center. Residents performed nearly all intubations. It is unclear whether the findings can be generalized to other clinical settings. Although we had information about the year of training of the emergency medicine residents, experience could vary between residents according to previous number of intubations and experience with each of the devices. The data were subject to self-report and recall bias. To account for possible confounders, we used a logistic regression model that incorporated a priori selected clinically relevant observed confounders. However, there are possible unknown or unmeasurable confounders that could account for observed differences. Future research should consider randomization of device use, as well as independent observer scoring of the airway difficulty.
Discussion
In this series of intubations performed at a large urban academic ED, we observed no difference in either first-pass or overall success between the C-MAC and the GlideScope video laryngoscope. The similar success rates persisted among important subgroups (including operator training level) and after multivariable adjustment. These data suggest that it may not be the specific device design, but rather the fundamental incorporation of video technology that provides the improved success observed in studies comparing video laryngoscopy to direct laryngoscopy.25,32,35,36 According to these findings, clinicians may opt for either GlideScope video laryngoscope or C-MAC, based on individual and institutional preference.
Previous studies suggest that multiple intubation attempts are associated with adverse events such as aspiration, hypoxemia, hypotension, and cardiac arrest.37-39 Collectively, these studies point to the prudence of first-pass success in ED intubation efforts. In clinical settings with difficult anatomy, previous studies suggest that video laryngoscopy may result in higher first-attempt success than conventional laryngoscopy.32 Piepho et al25 found that in patients with a Cormack-Lehane grade 3 or 4 view with direct laryngoscopy, the use of video laryngoscope improved glottis visualization in 94% of patients and intubation was successful in all but 1 case. A recent meta-analysis of studies comparing the GlideScope video laryngoscope with direct laryngoscopy found an improved grade of view and first-attempt success rate in intubations performed by “nonexperts;” however, most of the studies analyzed excluded known or predicted difficult intubations.22 For ED intubations, both the GlideScope video laryngoscope and the C-MAC have been shown to increase grade of view and first-attempt success.27,32,35
Despite the similar success rates observed in our series, clinicians should be aware of the fundamental design differences between the GlideScope video laryngoscope and the C-MAC devices. These distinct features require slightly different laryngoscopic techniques. The GlideScope video laryngoscope is designed with a hyperangulated blade. Although allowing indirect visualization of the glottis, this design often requires the use of a specially shaped stylet.40 Direct laryngoscopy is not feasible with the GlideScope video laryngoscope, given the hyperacute blade curvature. However, the GlideScope video laryngoscope may be useful in situations in which it is impossible to align the oral, pharyngeal, and laryngeal axes, such as situations involving tongue swelling, pharyngeal obstruction, or cervical spine immobilization.2,11,15,41,42 In contrast, the C-MAC design resembles a traditional Macintosh blade, allowing laryngoscopy to be accomplished by either direct laryngoscopy or indirect video visualization. However, in extraordinarily difficult situations in which the visual axes of the airway cannot be aligned, the hyperacute bend of the GlideScope video laryngoscope may offer an advantage. Practitioners should be aware of these distinctions when choosing a particular video laryngoscope device.
In conclusion in this study of video laryngoscopy in the ED, the C-MAC and the GlideScope video laryngoscope result in similar rates of first-pass and overall intubation success. The GlideScope video laryngoscope and the C-MAC are both excellent options for a video laryngoscopy system in the ED.
Acknowledgments
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist.
Appendix E1
Logistic regression models for successful intubation.*
| First-Pass Success | Overall Success | |||
|---|---|---|---|---|
|
|
|
|||
| OR | 95% CI | OR | 95%CI | |
| Device=GVL (vs C-MAC)† | 1.1 | 0.6–2.1 | 1.2 | 0.5–3.1 |
| Patient characteristics | ||||
| Age | 1.0 | 1.0–1.0 | 1.0 | 1.0–1.0 |
| Male‡ | 0.5 | 0.3–1.0 | 1.2 | 0.3–4.1 |
| Trauma§ | 1.6 | 0.9–3.0 | 1.0 | 0.3–3.7 |
| Number of DACs | ||||
| 0 | [Reference] | [Reference] | ||
| 1 | 0.7 | 0.3–2.0 | 1.2 | 0.1–9.4 |
| 2 | 0.3 | 0.1–0.8 | 0.4 | 0.04–3.5 |
| 3 or more | 0.3 | 0.1–0.9 | 0.5 | 0.05–4.9 |
| Intubation characteristics | ||||
| Reason for intubation | ||||
| Airway protection | [Reference] | [Reference] | ||
| Respiratory failure | 1.3 | 0.5–3.1 | 1.6 | 0.3–8.7 |
| Cardiac arrest | 0.2 | 0.1–0.7 | 0.6 | 0.1–5.2 |
| Patient control | 1.2 | 0.4–3.5 | N/A‖ | N/A‖ |
| Hypoxia | 1.3 | 0.1–13.6 | 0.1 | 0–1.5 |
| Reason for device | ||||
| Standard | [Reference] | [Reference] | ||
| Difficult | 0.5 | 0.3–1.2 | 0.5 | 0.1–3.1 |
| Education | 1.1 | 0.4–2.6 | 1.0 | 0.1–7.2 |
| Paralytic used | [Reference] | [Reference] | ||
| None | 1.6 | 0.4–6.1 | 1.1 | |
| Rocuronium | 1.6 | 0.4–5.8 | 0.8 | 0.1–11.5 |
| Succinylcholine | 0.1–5.2 | |||
| Sedative used | ||||
| None | [Reference] | [Reference] | ||
| Etomidate | 0.7 | 0.2–2.6 | 2.9 | 0.5–16.0 |
| Ketamine | 0.7 | 0.2–3.0 | N/A‖ | N/A‖ |
| Propofol | 1.9 | 0.2–20.6 | N/A‖ | N/A‖ |
| Other | 0.2 | 0.01–4.0 | N/A‖ | N/A‖ |
| Operator characteristics | ||||
| Operator PGY | ||||
| EMR 1 | [Reference] | [Reference] | ||
| EMR 2 | 2.5 | 1.3–4.7 | 2.0 | 0.5–8.5 |
| EMR 3 or attending | 2.5 | 1.4–4.5 | 0.6 | 0.2–1.7 |
Clustered by provider.
Reference: Female sex.
Reference: Device=C-MAC.
Reference: Medical.
Dropped because it predicted success perfectly.
Footnotes
Author contributions: JCS conceived the study, designed the data collection instrument, and managed the database. All authors performed statistical analysis and contributed to drafting the article. JCS takes responsibility for the paper as a whole.
References
- 1.Aziz M, Brambrink A. The Storz C-MAC video laryngoscope: description of a new device, case report, and brief case series. J Clin Anesth. 2011;23:149–152. doi: 10.1016/j.jclinane.2010.01.006. [DOI] [PubMed] [Google Scholar]
- 2.Benjamin FJ, Boon D, French RA. An evaluation of the GlideScope, a new video laryngoscope for difficult airways: a manikin study. Eur J Anaesthesiol. 2006;23:517–521. doi: 10.1017/S0265021506000147. [DOI] [PubMed] [Google Scholar]
- 3.Cooper RM. Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway. Can J Anaesth. 2003;50:611–613. doi: 10.1007/BF03018651. [DOI] [PubMed] [Google Scholar]
- 4.Cooper RM, Pacey JA, Bishop MJ, et al. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anaesth. 2005;52:191–198. doi: 10.1007/BF03027728. [DOI] [PubMed] [Google Scholar]
- 5.Hirabayashi Y. Airway scope: initial clinical experience with novice personnel. Can J Anaesth. 2007;54:160–161. doi: 10.1007/BF03022021. [DOI] [PubMed] [Google Scholar]
- 6.Sakles JC, Rodgers R, Keim SM. Optical and video laryngoscopes for emergency airway management. Intern Emerg Med. 2008;3:139–143. doi: 10.1007/s11739-008-0101-y. [DOI] [PubMed] [Google Scholar]
- 7.Andersen LH, Rovsing L, Olsen KS. GlideScope videolaryngoscope vs. Macintosh direct laryngoscope for intubation of morbidly obese patients: a randomized trial. Acta Anaesthesiol Scand. 2011;55:1090–1097. doi: 10.1111/j.1399-6576.2011.02498.x. [DOI] [PubMed] [Google Scholar]
- 8.Ayoub CM, Kanazi GE, Al Alami A, et al. Tracheal intubation following training with the GlideScope compared to direct laryngoscopy. Anaesthesia. 2010;65:674–678. doi: 10.1111/j.1365-2044.2010.06335.x. [DOI] [PubMed] [Google Scholar]
- 9.Fonte M, Oulego-Erroz I, Nadkarni L, et al. A randomized comparison of the GlideScope videolaryngoscope to the standard laryngoscopy for intubation by pediatric residents in simulated easy and difficult infant airway scenarios. Pediatr Emerg Care. 2011;27:398–402. doi: 10.1097/PEC.0b013e318217b550. [DOI] [PubMed] [Google Scholar]
- 10.Kaki AM, Almarakbi WA, Fawzi HM, et al. Use of Airtraq, C-Mac, and Glidescope laryngoscope is better than Macintosh in novice medical students' hands: a manikin study. Saudi J Anaesth. 2011;5:376–381. doi: 10.4103/1658-354X.87266. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.McElwain J, Malik MA, Harte BH, et al. Comparison of the C-MAC videolaryngoscope with the Macintosh, Glidescope, and Airtraq laryngoscopes in easy and difficult laryngoscopy scenarios in manikins. Anaesthesia. 2010;65:483–489. doi: 10.1111/j.1365-2044.2010.06307.x. [DOI] [PubMed] [Google Scholar]
- 12.Nouruzi-Sedeh P, Schumann M, Groeben H. Laryngoscopy via Macintosh blade versus GlideScope: success rate and time for endotracheal intubation in untrained medical personnel. Anesthesiology. 2009;110:32–37. doi: 10.1097/ALN.0b013e318190b6a7. [DOI] [PubMed] [Google Scholar]
- 13.Kim HJ, Chung SP, Park IC, et al. Comparison of the GlideScope video laryngoscope and Macintosh laryngoscope in simulated tracheal intubation scenarios. Emerg Med J. 2008;25:279–282. doi: 10.1136/emj.2007.052803. [DOI] [PubMed] [Google Scholar]
- 14.Lim TJ, Lim Y, Liu EH. Evaluation of ease of intubation with the GlideScope or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy. Anaesthesia. 2005;60:180–183. doi: 10.1111/j.1365-2044.2004.04038.x. [DOI] [PubMed] [Google Scholar]
- 15.Malik MA, Maharaj CH, Harte BH, et al. Comparison of Macintosh, Truview EVO2, Glidescope, and Airwayscope laryngoscope use in patients with cervical spine immobilization. Br J Anaesth. 2008;101:723–730. doi: 10.1093/bja/aen231. [DOI] [PubMed] [Google Scholar]
- 16.Malik MA, O'Donoghue C, Carney J, et al. Comparison of the Glidescope, the Pentax AWS, and the Truview EVO2 with the Macintosh laryngoscope in experienced anaesthetists: a manikin study. Br J Anaesth. 2009;102:128–134. doi: 10.1093/bja/aen342. [DOI] [PubMed] [Google Scholar]
- 17.Malik MA, Subramaniam R, Maharaj CH, et al. Randomized controlled trial of the Pentax AWS, Glidescope, and Macintosh laryngoscopes in predicted difficult intubation. Br J Anaesth. 2009;103:761–768. doi: 10.1093/bja/aep266. [DOI] [PubMed] [Google Scholar]
- 18.Aziz MF, Healy D, Kheterpal S, et al. Routine clinical practice effectiveness of the Glidescope in difficult airway management: an analysis of 2,004 Glidescope intubations, complications, and failures from two institutions. Anesthesiology. 2011;114:34–41. doi: 10.1097/ALN.0b013e3182023eb7. [DOI] [PubMed] [Google Scholar]
- 19.Byhahn C, Iber T, Zacharowski K, et al. Tracheal intubation using the mobile C-MAC video laryngoscope or direct laryngoscopy for patients with a simulated difficult airway. Minerva Anestesiol. 2010 [PubMed] [Google Scholar]
- 20.Cavus E, Thee C, Moeller T, et al. A randomised, controlled crossover comparison of the C-MAC videolaryngoscope with direct laryngoscopy in 150 patients during routine induction of anaesthesia. BMC Anesthesiol. 2011;11:6. doi: 10.1186/1471-2253-11-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Choi GS, Lee EH, Lim CS, et al. A comparative study on the usefulness of the Glidescope or Macintosh laryngoscope when intubating normal airways. Korean J Anesthesiol. 2011;60:339–343. doi: 10.4097/kjae.2011.60.5.339. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Griesdale DE, Liu D, McKinney J, et al. Glidescope(R) video-laryngoscopy versus direct laryngoscopy for endotracheal intubation: a systematic review and meta-analysis. Can J Anaesth. 2012;59:41–52. doi: 10.1007/s12630-011-9620-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Maassen R, van Zundert A. Comparison of the C-MAC videolaryngoscope with the Macintosh, Glidescope and Airtraq laryngoscopes in easy and difficult laryngoscopy scenarios in manikins. Anaesthesia. 2010;65:955. doi: 10.1111/j.1365-2044.2010.06464.x. author reply 955-956. [DOI] [PubMed] [Google Scholar]
- 24.McElwain J, Laffey JG. Comparison of the C-MAC(R), Airtraq(R), and Macintosh laryngoscopes in patients undergoing tracheal intubation with cervical spine immobilization. Br J Anaesth. 2011;107:258–264. doi: 10.1093/bja/aer099. [DOI] [PubMed] [Google Scholar]
- 25.Piepho T, Fortmueller K, Heid FM, et al. Performance of the C-MAC video laryngoscope in patients after a limited glottic view using Macintosh laryngoscopy. Anaesthesia. 2011;66:1101–1105. doi: 10.1111/j.1365-2044.2011.06872.x. [DOI] [PubMed] [Google Scholar]
- 26.Platts-Mills TF, Campagne D, Chinnock B, et al. A comparison of GlideScope video laryngoscopy versus direct laryngoscopy intubation in the emergency department. Acad Emerg Med. 2009;16:866–871. doi: 10.1111/j.1553-2712.2009.00492.x. [DOI] [PubMed] [Google Scholar]
- 27.Sakles JC, Mosier JM, Chiu S, et al. Tracheal intubation in the emergency department: a comparison of GlideScope(R) video laryngoscopy to direct laryngoscopy in 822 intubations. J Emerg Med. 2012;42:400–405. doi: 10.1016/j.jemermed.2011.05.019. [DOI] [PubMed] [Google Scholar]
- 28.Teoh WH, Saxena S, Shah MK, et al. Comparison of three videolaryngoscopes: Pentax Airway Scope, C-MAC, Glidescope vs the Macintosh laryngoscope for tracheal intubation. Anaesthesia. 2010;65:1126–1132. doi: 10.1111/j.1365-2044.2010.06513.x. [DOI] [PubMed] [Google Scholar]
- 29.Xanthos T, Stroumpoulis K, Bassiakou E, et al. Glidescope((R)) videolaryngoscope improves intubation success rate in cardiac arrest scenarios without chest compressions interruption: a randomized cross-over manikin study. Resuscitation. 2011;82:464–467. doi: 10.1016/j.resuscitation.2010.12.011. [DOI] [PubMed] [Google Scholar]
- 30.Xue FS, Yuan YJ, Liao X, et al. Is Glidescope(R) videolaryngoscope more effective than Macintosh laryngoscope for emergent intubation during chest compression? Resuscitation. 2011;82:956. doi: 10.1016/j.resuscitation.2011.02.049. author reply 957-958. [DOI] [PubMed] [Google Scholar]
- 31.Yuan YJ, Xue FS, Wang Q, et al. Comparison of the tracheal intubation using Macintosh laryngoscope and GlideScope(R) videolaryngoscope by advanced cardiac life support providers in a manikin study. Minerva Anestesiol. 2011;77:558–559. author reply 560-561. [PubMed] [Google Scholar]
- 32.Mosier JM, Stolz U, Chiu S, et al. Difficult airway management in the emergency department: GlideScope videolaryngoscopy compared to direct laryngoscopy. J Emerg Med. 2012;42:629–634. doi: 10.1016/j.jemermed.2011.06.007. [DOI] [PubMed] [Google Scholar]
- 33.Bair AE, Caravelli R, Tyler K, et al. Feasibility of the preoperative Mallampati airway assessment in emergency department patients. J Emerg Med. 2010;38:677–680. doi: 10.1016/j.jemermed.2008.12.019. [DOI] [PubMed] [Google Scholar]
- 34.Levitan RM, Everett WW, Ochroch EA. Limitations of difficult airway prediction in patients intubated in the emergency department. Ann Emerg Med. 2004;44:307–313. doi: 10.1016/j.annemergmed.2004.05.006. [DOI] [PubMed] [Google Scholar]
- 35.Sakles JC, Mosier J, Chiu S, et al. A Comparison of the C-MAC video laryngoscope to the macintosh direct laryngoscope for intubation in the emergency department. Ann Emerg Med. 2012 doi: 10.1016/j.annemergmed.2012.03.031. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 36.Sakles JC, Mosier JM, Chiu S, et al. Tracheal intubation in the emergency department: a comparison of GlideScope((R)) video laryngoscopy to direct laryngoscopy in 822 intubations. J Emerg Med. 2011 doi: 10.1016/j.jemermed.2011.05.019. [DOI] [PubMed] [Google Scholar]
- 37.Sakles J, Chiu S, Mosier J, et al. The importance of first pass success when performing orotracheal intubation in the emergency department. Acad Emerg Med. doi: 10.1111/acem.12055. doi:10:1111/acem.12055. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38.Hasegawa K, Shigemitsu K, Hagiwara Y, et al. Association between repeated intubation attempts and adverse events in emergency departments: an analysis of a multicenter prospective observational study. Ann Emerg Med. 2012 doi: 10.1016/j.annemergmed.2012.04.005. [DOI] [PubMed] [Google Scholar]
- 39.Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg. 2004;99:607–613. doi: 10.1213/01.ANE.0000122825.04923.15. table of contents. [DOI] [PubMed] [Google Scholar]
- 40.Sakles JC, Kalin L. The effect of stylet choice on the success rate of intubation using the GlideScope video laryngoscope in the emergency department. Acad Emerg Med. 2012;19:235–238. doi: 10.1111/j.1553-2712.2011.01271.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 41.Lim Y, Yeo SW. A comparison of the GlideScope with the Macintosh laryngoscope for tracheal intubation in patients with simulated difficult airway. Anaesth Intensive Care. 2005;33:243–247. doi: 10.1177/0310057X0503300215. [DOI] [PubMed] [Google Scholar]
- 42.Savoldelli GL, Schiffer E, Abegg C, et al. Comparison of the Glidescope, the McGrath, the Airtraq and the Macintosh laryngoscopes in simulated difficult airways. Anaesthesia. 2008;63:1358–1364. doi: 10.1111/j.1365-2044.2008.05653.x. [DOI] [PubMed] [Google Scholar]