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Long B, Gottlieb M. Video laryngoscopy versus fiberoptic bronchoscopy for awake tracheal intubation. Academic Emergency Medicine. Published online November 13, 2024:acem.15051.

Study Population: 873 participants from 11 studies of adults undergoing awake intubation

Efficacy Endpoints

Time to intubation, lower risk of oxygen desaturation <90%, successful intubation on first attempt, patient-reported satisfaction

Harm Endpoints

Failed intubation and adverse events arising from intubation procedure (sore throat/hoarseness)

Narrative

Tracheal intubation is a high-risk procedure particularly as it may require sedation and paralysis.1^, 2^, 3 Awake intubation is a potential option for patients with anticipated or known difficult anatomic or physiologic airways, as it allows for spontaneous breathing and maintenance of airway tone by utilizing topical anesthetics with or without sedative agents in the absence of paralytic administration during the intubation attempt.2^, 3^, 4^, 5 Indications for awake intubation include patients with significant risk of a difficult anatomic or physiologic airway (e.g., angioedema, Ludwig's angina, oral mass) who do not require immediate airway protection, are able to tolerate the procedure, and are at low risk of vomiting. One method of awake intubation is using fiberoptic bronchoscopy, which requires familiarity with the necessary equipment, extensive knowledge of airway anatomy, and an understanding of local anesthesia and sedation strategies.6^, 7^, 8^, 9 On the other hand, video laryngoscopes provide improved glottic visualization and first-pass success, and they are typically easier to use and master compared to fiberoptic bronchoscopes.1^, 3^, 10 Thus, video laryngoscopes have been used as an alternative device for use in awake intubation. Two prior meta-analyses comparing the two techniques found shorter intubation time with video laryngoscopy, but there was no difference in other outcomes. Both meta-analyses reported significant heterogeneity among the trials.11^, 12

The updated systematic review summarized here included 11 randomized controlled trials (RCTs; n = 873 participants) and compared video laryngoscopy and fiberoptic bronchoscopy for patients undergoing awake intubation.13 The primary outcome was time to intubation. Secondary outcomes included rate of successful intubation on first attempt, rates of failed intubation, patient-reported satisfaction, oxygen desaturation <90%, and any other complications or adverse events (sore throat/hoarseness) from the intubation procedure. They utilized trial sequential analysis to evaluate the conclusiveness of the evidence concerning intubation time.

All 11 RCTs were published between 2012 and 2023 and evaluated awake intubation performed by anesthesiologists for elective bariatric, oral and maxillofacial, otolaryngology, cervical spine, gynecologic, abdominal, or urologic surgeries.13 Two trials utilized the nasal route for intubation, while the remaining nine RCTs used the oral route. Video laryngoscope devices included AceScope, Airtraq, Bullard, C-MAC D-BLADE, GlideScope, McGrath, and Pentax AWS.

Compared to fiberoptic bronchoscopy, video laryngoscopy was associated with reduced time to intubation (standardized mean difference [SMD] −1.97 min, 95% CI −2.78 to −1.15 min, 10 studies). Three studies evaluated GlideScope and found reduced time to intubation (SMD −2.50 min, 95% CI −4.87 to −0.13 min). Other video laryngoscope devices were also associated with reduced time to intubation (SMD −1.77 min, 95% CI −2.66 to −0.87 min). Video laryngoscopy was associated with reduced risk of oxygen desaturation <90% (risk ratio [RR] −0.70, 95% CI −1.40 to −0.01, seven studies). Regarding oxygen desaturation <90%, video laryngoscopy was associated with an absolute risk reduction of 5.2%, number needed to treat 20, when compared to fiberoptic laryngoscopy. There was no difference in first-attempt successful intubation (RR 0.01, 95% CI −0.06 to 0.09, nine studies), failed intubation (RR 0.46, 95% CI −0.52 to 1.44, nine studies), or sore throat/hoarseness (RR 0.07, 95% CI −0.48 to 0.62, 3 studies). Patient satisfaction did not differ in seven studies. Trial sequential analysis for time to intubation suggested the results were conclusive.13

Caveats

There are several factors that influence the interpretation of these results.13 First, there was significant heterogeneity among the included trials involving several factors including the type of intubation device, indication for awake intubation, operator experience, types of medications used for sedation and topical anesthesia, and trial inclusion criteria. This heterogeneity limited subgroup analysis, particularly for the video laryngoscope devices used. Second, the analysis of intubation time as the primary outcome varied among the included studies, with five RCTs using mean and standard deviation and the other five trials using median and interquartile range. Third, all RCTs were conducted in the anesthesiology setting in elective surgeries. Indeed, five studies did not require inclusion of patients with known or anticipated difficult airways, which is the primary indication for awake intubation. This limits the application of the findings of this systematic review to the emergency department (ED) setting. Fourth, the sedation protocols and sedation targets varied among the included trials. Ketamine, a commonly utilized medication in the ED setting, was not used in any of the included RCTs. Rather, the included studies utilized a variety of medications such as remifentanil, midazolam, or propofol. Ten trials utilized topical anesthesia with lidocaine, while one used transtracheal injection and two used superior laryngeal nerve blockade and tracheal block. Fifth, blinding of operators and outcomes assessors was not possible, which may lead to bias. Finally, the definition of the airway operator as “expert” varied with both devices across all the included studies, with different levels of experience in the included trials.

Based on current data, video laryngoscopy may be associated with reduced time to intubation and risk of oxygen desaturation <90% compared to fiberoptic bronchoscopy in patients undergoing awake intubation for elective surgery. However, these results may not be generalizable to the ED setting. In addition, significant heterogeneity is a serious validity threat that limits our ability to draw conclusions from the existing evidence. Therefore, we have assigned a color recommendation of yellow (more data needed) for the evaluation of video laryngoscopy compared to fiberoptic bronchoscopy in awake intubation. Importantly, there is no consensus that fiberoptic laryngoscopy is more successful than video laryngoscopy. For predicted difficult airways where awake intubation is being considered without paralysis during the attempt in the ED setting, video laryngoscopy appears to be as effective with lower complications rates.14 Thus, emergency physicians should consider video laryngoscopy as an option for awake intubation, rather than delaying a necessary procedure for fiberoptic equipment. Further data are needed in the ED and critical care settings using clearly defined standardized sedation and anesthesia protocols and outcomes.

The original manuscript was published in Academic Emergency Medicine as part of the partnership between TheNNT.com and AEM.

Author

Brit Long, MD; Michael Gottlieb, MD
Supervising Editors: Shahriar Zehtabchi, MD

Published/Updated

November 26, 2024