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Abstract
Objective To investigate the use and success rates of the GlideScope (GVL) by emergency physicians (EPs) during the initial two years after its introduction.
Methods We performed an observational study using registry data of five emergency departments. The success rates in adult patients were evaluated and compared with those of conventional laryngoscope (CL).
Results The GVL was used in 345 (10.7%) of 3233 intubation attempts by EPs. The overall success rate of the GVL was not higher than a CL (79.1% vs 77.6%, p=0.538). The success rate for the patients with difficult airway was higher in the GVL than a CL (80.0% vs 50.4%, p<0.001).
Conclusion The GVL was not used frequently by EPs during the initial two years after its introduction. Although the GVL provides a better glottic view, the overall success rates were similar to a CL. The GVL may be useful in patients with difficult airway.
- Airway
- emergency care systems, emergency departments
- equipment evaluation
- GlideScope video laryngoscope
- laryngoscopic intubation
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- Airway
- emergency care systems, emergency departments
- equipment evaluation
- GlideScope video laryngoscope
- laryngoscopic intubation
The GlideScope video laryngoscope (GVL) (Saturn Biomedical Systems, Burnaby, British Columbia, Canada) is a new video laryngoscope with a high-resolution camera embedded within the blade and provides similar or superior laryngeal visualisation in both routine and difficult airways.1 Several studies have been carried out of endotracheal intubation (ETI) using the GVL in the operating room by anaesthesiologists.2–4 However, there are few reports of the use of the GVL in emergency departments (ED) by emergency physicians. The purpose of this study was to investigate the use of the GVL and success rates of ETI using the GVL performed by emergency physicians in ED during the initial 2 years after its introduction.
Methods
After institutional review board approval of each hospital, we performed a prospective multicentre observational study using the web-based emergency airway registry from April 2006 to March 2008. The main data collected include patient demographics, difficulty assessment, number of attempts, intubation methods and devices used in each attempt, Cormack and Lehane (C&L) grade and the percentage of glottis opening (POGO) scores in each attempt and immediate complications. All data collected were verified for completeness by the site investigator and recorded on the web-based registration system. An ETI attempt was defined as a single pass of a blade into the mouth or a single pass of the tube into the nares. The rescue attempts were defined as the next attempts after failure of an initial attempt. The difficult airway was defined as a case that satisfied more than one of the four components (look externally, evaluate 3–3–2, obstruction, neck mobility) of the LEMON method.5
We analysed the registry data of five ED that have the GVL. The success rates in the first and rescue attempts and for the patients with anticipated difficult airways were investigated. The χ2 test was used to compare the success rates of ETI using the GVL and a conventional laryngoscope. The Wilcoxon signed rank test was used to compare the POGO score in ETI using the GVL and conventional laryngoscopes. For all statistical analysis, SPSS 12K for Windows was used. A p value less than 0.05 was considered significant.
Results
A total of 3233 attempts in 2543 patients was performed by emergency physicians. Emergency physicians used the GVL for 345 attempts (10.7%) in 303 patients. The success rate of the GVL was 80.8% in first attempts and 76.2% in rescue attempts. The overall success rate of the GVL was slightly higher than a conventional laryngoscope but the difference was not significant (79.1% vs 77.6%, p=0.538). In rescue attempts, the success rate of the GVL was greater than conventional laryngoscopes irrespective of the airway devices that were used in previous attempts (table 1).
Success rates of ETI using a conventional laryngoscope and the GVL
In 503 patients with an anticipated difficult airway, the GVL was used for 164 attempts and a conventional laryngoscope was used for 712 attempts. The success rate of the GVL (80.0%) was significantly greater than that of conventional laryngoscopes (50.4%; p<0.001). There were 19 surgical airway management cases (0.7%). Among them, nine cases were performed after failure of the intubation attempt with a conventional laryngoscope, one case was done after failure with the GVL and one case was done after failure with both laryngoscopes.
For patients with a non-difficult airway, a C&L grade I view was obtained in 55.8% of attempts in the GVL group and 36.2% in the conventional laryngoscope group. The ratio of C&L grade III and IV views was 9.4% in the GVL group and 22.4% in the conventional laryngoscope group. These proportions were similar in the patients with an anticipated difficult airway (figure 1). The median POGO score of the GVL group (80) was significantly higher than that of the conventional laryngoscope group (60) (p<0.001).
Cormack and Lehane grade associated with use of the GlideScope and a conventional laryngoscope according to airway difficulty. CL=conventional laryngoscope; GVL=GlideScope video laryngoscope; GEG=glottic exposure grade.
Discussion
In our study, the GVL was used in only 10.7% of the total attempts by emergency physicians in five academic ED during the initial 2 years after its introduction, and 36.5% of attempts using the GVL were applied for a rescue attempt. The results of our study are similar to a recent report by Lim and Goh.6 They reported that the GVL was used in less than 7% of total intubations in their ED during a 6-month period. They suggested multifactorial reasons for the low utilisation rate, such as the perception that it is difficult to use, lack of formal teaching, limited experience and similar success rates with a conventional laryngoscope.
The GVL generally provide a better laryngoscopic view than a conventional laryngoscope.7 In our study, the GVL provided substantially higher C&L grades and POGO scores than a conventional laryngoscope. However, the overall success rate of ETI using the GVL was not significantly greater than that of a conventional laryngoscope. There are some possible reasons for the results. Most emergency physicians are more experienced with conventional laryngoscopes and sometimes have difficulty with the insertion of the endotracheal tube due to the steep angle of the GVL.8 Some cases in our data showed unsuccessful intubation despite excellent visualisation.
The GVL has been used successfully in patients with difficult airways in operating rooms.9 10 In our study, the success rate was significantly greater using the GVL than a conventional laryngoscope in patients with an anticipated difficult airway. Our data suggest that the GVL may also be useful in patients with difficult airways in ED.
Our study has several limitations. First, the data were based on reports recorded at several institutions, and reporting errors may have occurred. Second, although we used a modified LEMON method for predicting difficult intubations, we could not standardise the pre-intubation assessment in all ED. Third, the intubation situations and intubators could not be controlled because this was an observational study. Therefore, we also cannot exclude the possibility that more trained or experienced emergency physicians prefer to use the GVL.
In conclusion, the GVL was not used frequently by emergency physicians during the initial 2 years after its introduction in five academic ED in Korea. Although the GVL provides a better glottic view, the overall success rates were similar to ETI using a conventional laryngoscope. The GVL may be useful in patients with difficult airways in ED.
Acknowledgments
The authors would like to thank Seung-Hwan Kim (Severance Hospital) who helped develop and improve the web-based registry and the three clinical fellows who assisted in entering the registry data from the two hospitals: Ji-Hoon Kim, Jung-Hee Wee (Seoul St Mary's Hospital) and Min-Hong Jwa (Severance Hospital). The authors also thank the residents of each hospital who helped with the registry input while treating emergency patients diligently.
Footnotes
Competing interests None.
Ethics approval This study was conducted with the approval of the Catholic University of Korea Seoul St Mary's Hospital, the Catholic University of Korea Uijeongbu St Mary's Hospital, Yonsei University Severance Hospital, Yonsei University Kangnam Severance Hospital, Hanyang University Guri Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.
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