- Email: [email protected]
Does the Use of Video Laryngoscopy Improve Intubation Outcomes?
AIRWAY/SYSTEMATIC REVIEW SNAPSHOT
TAKE-HOME MESSAGE In adult patients, video laryngoscopy improves the glottic view but does not improve first-attempt success. In patients with anticipated difficult airways, video laryngoscopy may reduce the risk of failed intubation. Does the Use of Video Laryngoscopy Improve Intubation Outcomes?
METHODS
EBEM Commentators
DATA SOURCES Authors searched the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE from inception through February 10, 2015. They searched Medical Subject Headings and free text for terms related to video laryngoscopy in both elective and emergency settings to include ICUs, emergency departments (EDs), and out-of-hospital environments. They further undertook backward and forward citation tracking for retrieved articles and key review articles to identify additional studies. STUDY SELECTION Two authors screened study titles and abstracts and then reviewed the full text of all potentially relevant articles. They included all randomized controlled trials and quasi-randomized studies of adults undergoing video versus direct laryngoscopy by Macintosh blade in a clinical, emergency, or out-ofhospital setting. DATA EXTRACTION AND SYNTHESIS Two authors extracted data from each study. They resolved data disagreements by discussion or adjudication by a third reviewer. The Cochrane Risk of Bias tool was used to assess study quality.1 Abstracted outcomes included failed intubation, successful first
Volume
-,
no.
-
:
-
2017
Michael D. April, MD, DPhil Brit Long, MD Department of Emergency Medicine San Antonio Uniformed Services Health Education Consortium Fort Sam Houston, TX
Results Pooled results for video laryngoscopy compared with direct laryngoscopy.
Outcome Failed intubation Successful first attempt Airway trauma Grade 1 Cormack-Lehane view Hypoxia Mortality
No. of Studies
No. of Subjects
38 36 29 22 8 2
4,127 4,731 3,110 2,240 1,319 663
The authors included 64 randomized controlled trials reporting outcomes for 7,044 subjects. Only 3 of these studies included patients requiring emergency airway management: one based in an ICU,5 one in a trauma center,6 and one in an out-of-hospital setting.7 The small number of emergency intubations identified precluded subgroup analysis of this population. The remaining 61 studies took place in an operating room setting and comprised elective surgical participants. The most commonly studied video laryngoscopy devices included GlideScope (Verathon, Bothwell, WA) (29 studies), Pentax AWS (Ambu Inc, Ballerup, Denmark) (20 studies), C-MAC (Karl Storz GmbH & Co KG, Tuttlingen, Germany) (9 studies), and McGrath
Odds Ratio (95% Confidence Interval) 0.35 1.27 0.68 6.77 0.39 1.09
(0.19–0.65) (0.77–2.09) (0.48–0.96) (4.17–10.98) (0.10–1.44) (0.65–1.82)
I2, % 52 79 25 74 70 29
(Aircraft Medical Limited, Edinburgh, UK) (8 studies). The authors reported fewer failed intubations and less airway trauma with video laryngoscopy compared with direct laryngoscopy (Table). Subgroup analysis demonstrated fewer failed intubations with video laryngoscopy among patients with a predicted difficult airway (odds ratio 0.28; 95% confidence interval 0.15 to 0.55; I2¼0%; n¼830). However, studies with no predicted difficult airways showed no decrease in failed intubation with video laryngoscopy (odds ratio 0.61; 95% confidence interval 0.22 to 1.67; I2¼56%; n¼1,743). Video laryngoscopy resulted in more grade 1 Cormack-Lehane glottis views. Annals of Emergency Medicine 1
Systematic Review Snapshot
attempt, complications, time to intubation, and grade 1 CormackLehane glottic view.2 Authors reported pooled effect size estimates as Mantel-Haenszel odds ratios with 95% confidence intervals; heterogeneity was estimated with I2.3 Review authors contacted individual study authors for further data if required. Finally, the study authors used Grading of Recommendations Assessment, Development and Evaluation criteria to assess quality of evidence.4
There were no differences between video and direct laryngoscopy in probability of successful first attempt, hypoxia, or mortality. Marked heterogeneity precluded pooled calculations of time to intubation.
Commentary Intubation is a critical component of emergency medicine practice. Although failure to intubate elective surgery patients simply results in case cancellation, failure to intubate ED patients may result in severe morbidity, mortality, or need for cricothyrotomy. Video laryngoscopy seeks to improve intubation success by optimizing the glottic view. Data from individual studies conflict with some studies concluding video and direct laryngoscopy result in similar outcomes,8 whereas others conclude video is superior.9 The Cochrane review summarized in this systematic review snapshot reported comparable first-attempt success between the 2 modalities and potentially fewer failed intubations with video laryngoscopy, primarily among patients with anticipated difficult airways. 2 Annals of Emergency Medicine
However, there are reasons emergency physicians should exercise caution in applying these results to their clinical practice. First, although the authors sought to include data from intubations in both emergency and elective scenarios, a majority of randomized controlled trials in this meta-analysis included patients in an operating room setting. Consequently, the generalizability of these results to ED intubations remains unclear. Second, no device consistently demonstrates 100% success, and it is likely that the ideal intubation device is highly patient and situation specific. The existing literature lacks sufficient sample size and diversity in terms of the study populations and settings to ascertain which patients are most likely to benefit from which devices. These results build on a metaanalysis summarized in a previous systematic review snapshot.10 The previous meta-analysis pooled data from a far smaller number of patients (1,196 versus 7,044 in the Cochrane review), did not examine intubation failure, and included both pediatric and adult subjects, yet it reported similar probabilities of first-pass success with both video and direct laryngoscopy.11 A separate Cochrane review compared video with direct laryngoscopy in pediatric patients, but there was substantial heterogeneity across studies, making it difficult to draw conclusions.12 Since the publication of the work by Lewis et al,13 additional randomized controlled trials comparing video and direct laryngoscopy among adults undergoing emergency intubation have been published. These studies have found no difference in the overall
probability of first-pass success in the ICU8 and out-of-hospital environments.14 Although conducted in non-ED settings, these data add further support for no difference in outcomes for emergency intubations performed using video versus direct laryngoscopy. For the time being, emergency physicians must therefore be proficient with multiple devices and exercise their clinical judgment in choosing which device to use for any given patient. As the literature continues to expand, additional data may become available specific to emergency intubations that will include stratified analyses focusing on children and other subgroups so that which patients most likely to benefit from the use of video laryngoscopy will be elucidated. Editor’s Note: This is a clinical synopsis, a regular feature of the Annals’ Systematic Review Snapshot (SRS) series. The source for this systematic review snapshot is: Lewis SR, Butler AR, Parker J, et al. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation. Cochrane Database Syst Rev. 2016;11:CD011136. 1. Higgins JPT, Green S, eds. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. 2011. Available at: http://handbook.cochrane. org. Accessed July 20, 2017. 2. Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anesthesia. 1984;39:1105-1111. 3. Sutton AJ, Higgins J. Recent developments in meta-analysis. Stat Med. 2008;27:625-650. 4. GRADE Working Group. GRADEpro GDT. 2014. Available at: https://gradepro.org. Accessed July 20, 2017. 5. Griesdale DEG, Chau A, Isac G, et al. Videolaryngoscopy versus direct laryngoscopy in critically ill patients: a pilot randomized trial. Can J Anaesth. 2012;59:1032-1039. 6. Yeatts DJ, Dutton RP, Hu PF, et al. Effect of video laryngoscopy on trauma patient survival. J Trauma Acute Care Surg. 2013;75:212-219. 7. Arima T, Nagata O, Miura T, et al. Comparative analysis of airway scope and
Volume
-,
no.
-
:
-
2017
Systematic Review Snapshot Macintosh laryngoscope for intubation primarily for cardiac arrest in prehospital setting. Am J Emerg Med. 2014;32:40-43. 8. Lascarrou JB, Boisrame-Helms J, Bailly A, et al. Video laryngoscopy vs direct laryngoscopy on successful first-pass orotracheal intubation among ICU patients: a randomized clinical trial. JAMA. 2017;317:483-493. 9. Silverberg MJ, Li N, Acquah SO, et al. Comparison of video laryngoscopy versus direct laryngoscopy during urgent endotracheal intubation: a randomized controlled trial. Crit Care Med. 2015;43:636-641. 10. Carlson JN, Brown CA. Does the use of video laryngoscopy improve intubation outcomes? Ann Emerg Med. 2014;64:165-166.
Volume
-,
no.
-
:
-
2017
11. Su YC, Chen CC, Lee YK, et al. Comparison of video laryngoscopes with direct laryngoscopy for tracheal intubation: a meta-analysis of randomised trials. Eur J Anesthesiol. 2011;28:788-795. 12. Abdelgadir IS, Phillips RS, Singh D, et al. Videolaryngoscopy versus direct laryngoscopy for tracheal intubation in children (excluding neonates) [review]. Cochrane Database Syst Rev. 2017;(5):CD011413. 13. Lewis SR, Butler AR, Parker J, et al. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation. Cochrane Database Syst Rev. 2016;11:CD011136. 14. Ducharme S, Kramer B, Gelbart D, et al. A pilot, prospective, randomized trial of video versus direct laryngoscopy for
paramedic endotracheal intubation. Resuscitation. 2017;114:121-126.
The views expressed herein are those of the authors and do not reflect the official policy or position of Brooke Army Medical Center, the US Army Medical Department, the US Army Office of the Surgeon General, the Department of the Army, the Department of the Air Force and Department of Defense, or the US government. Michael Brown, MD, MSc, Jestin N. Carlson, MD, MS, and Alan Jones, MD, serve as editors of the SRS series.
Annals of Emergency Medicine 3
TAKE-HOME MESSAGE In adult patients, video laryngoscopy improves the glottic view but does not improve first-attempt success. In patients with anticipated difficult airways, video laryngoscopy may reduce the risk of failed intubation. Does the Use of Video Laryngoscopy Improve Intubation Outcomes?
METHODS
EBEM Commentators
DATA SOURCES Authors searched the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE from inception through February 10, 2015. They searched Medical Subject Headings and free text for terms related to video laryngoscopy in both elective and emergency settings to include ICUs, emergency departments (EDs), and out-of-hospital environments. They further undertook backward and forward citation tracking for retrieved articles and key review articles to identify additional studies. STUDY SELECTION Two authors screened study titles and abstracts and then reviewed the full text of all potentially relevant articles. They included all randomized controlled trials and quasi-randomized studies of adults undergoing video versus direct laryngoscopy by Macintosh blade in a clinical, emergency, or out-ofhospital setting. DATA EXTRACTION AND SYNTHESIS Two authors extracted data from each study. They resolved data disagreements by discussion or adjudication by a third reviewer. The Cochrane Risk of Bias tool was used to assess study quality.1 Abstracted outcomes included failed intubation, successful first
Volume
-,
no.
-
:
-
2017
Michael D. April, MD, DPhil Brit Long, MD Department of Emergency Medicine San Antonio Uniformed Services Health Education Consortium Fort Sam Houston, TX
Results Pooled results for video laryngoscopy compared with direct laryngoscopy.
Outcome Failed intubation Successful first attempt Airway trauma Grade 1 Cormack-Lehane view Hypoxia Mortality
No. of Studies
No. of Subjects
38 36 29 22 8 2
4,127 4,731 3,110 2,240 1,319 663
The authors included 64 randomized controlled trials reporting outcomes for 7,044 subjects. Only 3 of these studies included patients requiring emergency airway management: one based in an ICU,5 one in a trauma center,6 and one in an out-of-hospital setting.7 The small number of emergency intubations identified precluded subgroup analysis of this population. The remaining 61 studies took place in an operating room setting and comprised elective surgical participants. The most commonly studied video laryngoscopy devices included GlideScope (Verathon, Bothwell, WA) (29 studies), Pentax AWS (Ambu Inc, Ballerup, Denmark) (20 studies), C-MAC (Karl Storz GmbH & Co KG, Tuttlingen, Germany) (9 studies), and McGrath
Odds Ratio (95% Confidence Interval) 0.35 1.27 0.68 6.77 0.39 1.09
(0.19–0.65) (0.77–2.09) (0.48–0.96) (4.17–10.98) (0.10–1.44) (0.65–1.82)
I2, % 52 79 25 74 70 29
(Aircraft Medical Limited, Edinburgh, UK) (8 studies). The authors reported fewer failed intubations and less airway trauma with video laryngoscopy compared with direct laryngoscopy (Table). Subgroup analysis demonstrated fewer failed intubations with video laryngoscopy among patients with a predicted difficult airway (odds ratio 0.28; 95% confidence interval 0.15 to 0.55; I2¼0%; n¼830). However, studies with no predicted difficult airways showed no decrease in failed intubation with video laryngoscopy (odds ratio 0.61; 95% confidence interval 0.22 to 1.67; I2¼56%; n¼1,743). Video laryngoscopy resulted in more grade 1 Cormack-Lehane glottis views. Annals of Emergency Medicine 1
Systematic Review Snapshot
attempt, complications, time to intubation, and grade 1 CormackLehane glottic view.2 Authors reported pooled effect size estimates as Mantel-Haenszel odds ratios with 95% confidence intervals; heterogeneity was estimated with I2.3 Review authors contacted individual study authors for further data if required. Finally, the study authors used Grading of Recommendations Assessment, Development and Evaluation criteria to assess quality of evidence.4
There were no differences between video and direct laryngoscopy in probability of successful first attempt, hypoxia, or mortality. Marked heterogeneity precluded pooled calculations of time to intubation.
Commentary Intubation is a critical component of emergency medicine practice. Although failure to intubate elective surgery patients simply results in case cancellation, failure to intubate ED patients may result in severe morbidity, mortality, or need for cricothyrotomy. Video laryngoscopy seeks to improve intubation success by optimizing the glottic view. Data from individual studies conflict with some studies concluding video and direct laryngoscopy result in similar outcomes,8 whereas others conclude video is superior.9 The Cochrane review summarized in this systematic review snapshot reported comparable first-attempt success between the 2 modalities and potentially fewer failed intubations with video laryngoscopy, primarily among patients with anticipated difficult airways. 2 Annals of Emergency Medicine
However, there are reasons emergency physicians should exercise caution in applying these results to their clinical practice. First, although the authors sought to include data from intubations in both emergency and elective scenarios, a majority of randomized controlled trials in this meta-analysis included patients in an operating room setting. Consequently, the generalizability of these results to ED intubations remains unclear. Second, no device consistently demonstrates 100% success, and it is likely that the ideal intubation device is highly patient and situation specific. The existing literature lacks sufficient sample size and diversity in terms of the study populations and settings to ascertain which patients are most likely to benefit from which devices. These results build on a metaanalysis summarized in a previous systematic review snapshot.10 The previous meta-analysis pooled data from a far smaller number of patients (1,196 versus 7,044 in the Cochrane review), did not examine intubation failure, and included both pediatric and adult subjects, yet it reported similar probabilities of first-pass success with both video and direct laryngoscopy.11 A separate Cochrane review compared video with direct laryngoscopy in pediatric patients, but there was substantial heterogeneity across studies, making it difficult to draw conclusions.12 Since the publication of the work by Lewis et al,13 additional randomized controlled trials comparing video and direct laryngoscopy among adults undergoing emergency intubation have been published. These studies have found no difference in the overall
probability of first-pass success in the ICU8 and out-of-hospital environments.14 Although conducted in non-ED settings, these data add further support for no difference in outcomes for emergency intubations performed using video versus direct laryngoscopy. For the time being, emergency physicians must therefore be proficient with multiple devices and exercise their clinical judgment in choosing which device to use for any given patient. As the literature continues to expand, additional data may become available specific to emergency intubations that will include stratified analyses focusing on children and other subgroups so that which patients most likely to benefit from the use of video laryngoscopy will be elucidated. Editor’s Note: This is a clinical synopsis, a regular feature of the Annals’ Systematic Review Snapshot (SRS) series. The source for this systematic review snapshot is: Lewis SR, Butler AR, Parker J, et al. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation. Cochrane Database Syst Rev. 2016;11:CD011136. 1. Higgins JPT, Green S, eds. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. 2011. Available at: http://handbook.cochrane. org. Accessed July 20, 2017. 2. Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anesthesia. 1984;39:1105-1111. 3. Sutton AJ, Higgins J. Recent developments in meta-analysis. Stat Med. 2008;27:625-650. 4. GRADE Working Group. GRADEpro GDT. 2014. Available at: https://gradepro.org. Accessed July 20, 2017. 5. Griesdale DEG, Chau A, Isac G, et al. Videolaryngoscopy versus direct laryngoscopy in critically ill patients: a pilot randomized trial. Can J Anaesth. 2012;59:1032-1039. 6. Yeatts DJ, Dutton RP, Hu PF, et al. Effect of video laryngoscopy on trauma patient survival. J Trauma Acute Care Surg. 2013;75:212-219. 7. Arima T, Nagata O, Miura T, et al. Comparative analysis of airway scope and
Volume
-,
no.
-
:
-
2017
Systematic Review Snapshot Macintosh laryngoscope for intubation primarily for cardiac arrest in prehospital setting. Am J Emerg Med. 2014;32:40-43. 8. Lascarrou JB, Boisrame-Helms J, Bailly A, et al. Video laryngoscopy vs direct laryngoscopy on successful first-pass orotracheal intubation among ICU patients: a randomized clinical trial. JAMA. 2017;317:483-493. 9. Silverberg MJ, Li N, Acquah SO, et al. Comparison of video laryngoscopy versus direct laryngoscopy during urgent endotracheal intubation: a randomized controlled trial. Crit Care Med. 2015;43:636-641. 10. Carlson JN, Brown CA. Does the use of video laryngoscopy improve intubation outcomes? Ann Emerg Med. 2014;64:165-166.
Volume
-,
no.
-
:
-
2017
11. Su YC, Chen CC, Lee YK, et al. Comparison of video laryngoscopes with direct laryngoscopy for tracheal intubation: a meta-analysis of randomised trials. Eur J Anesthesiol. 2011;28:788-795. 12. Abdelgadir IS, Phillips RS, Singh D, et al. Videolaryngoscopy versus direct laryngoscopy for tracheal intubation in children (excluding neonates) [review]. Cochrane Database Syst Rev. 2017;(5):CD011413. 13. Lewis SR, Butler AR, Parker J, et al. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation. Cochrane Database Syst Rev. 2016;11:CD011136. 14. Ducharme S, Kramer B, Gelbart D, et al. A pilot, prospective, randomized trial of video versus direct laryngoscopy for
paramedic endotracheal intubation. Resuscitation. 2017;114:121-126.
The views expressed herein are those of the authors and do not reflect the official policy or position of Brooke Army Medical Center, the US Army Medical Department, the US Army Office of the Surgeon General, the Department of the Army, the Department of the Air Force and Department of Defense, or the US government. Michael Brown, MD, MSc, Jestin N. Carlson, MD, MS, and Alan Jones, MD, serve as editors of the SRS series.
Annals of Emergency Medicine 3