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ORIGINAL ARTICLE
Year : 2012  |  Volume : 6  |  Issue : 2  |  Page : 174-179  

Orotracheal intubation of morbidly obese patients, comparison of GlideScope® video laryngoscope and the LMA CTrach with direct laryngoscopy


Department of Anesthesia and Intensive Care, Faculty of Medicine, Zagazig University, Zagazig, Egypt

Date of Web Publication11-Mar-2013

Correspondence Address:
Gamal T Yousef
Department of Anesthesia and Intensive Care, Faculty of Medicine, Zagazig University, Zagazig
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0259-1162.108304

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   Abstract 

Background: Morbidly obese patients are at increased risk of difficult mask ventilation and intubation as well as increased risk of hypoxemia during tracheal intubation. Recently, new video-assisted intubation devices have been developed . The GlideScope® videolaryngoscope and LMA CTrach (CT) allows continuous video-endoscopy of the tracheal intubation procedure.
Objective: this study is to determine whether the GlideScope® videolaryngoscope (GVL) and the LMA CTrach (CT) provide the best airway management, measured primarily in intubation difficulty scale (IDS) scores, time and numbers of intubation attempts, and improvement in the intubation success rate of morbidly obese patients when compared with the direct Macintosh laryngoscope (DL) .
Materials and Methods: After Ethics' Committee approval, 90 morbidly obese patients (BMI > 35 kg/m 2 ) scheduled for general, gynecological, and bariatric surgery were included in this prospective study. Patients were randomly assigned in three groups: tracheal intubation using direct laryngoscopy (DL), GlideScope® videolaryngoscope (GVL) or the LMA CTrach (CT). Characteristics and consequences of airway management were evaluated. The primary outcome was the intubation difficulty scale score (IDS), Secondary outcomes were theintubation time, overall success rate, number of attempts, Cormack-Lehane grade, subjective difficulty of intubation, desaturation and upper airway morbidity.
Results: Difficulty in facemask ventilation was similar in the three groups. IDS scores were significantly lower with GVL and CT than with DL. The mean TTI was 14 s faster in patients intubated with the GVL (86 s, IQR: 68-115) compared with DL (100 s, IQR; 80-150), and was 34 s faster when compared with CT (120 s, IQR; 95-180). The success rate of tracheal intubation was lower with the DL (80%) compared with the GVL (100%) or the CT (100%). Six cases of failed intubation occurred in group DL, four patients from the six patients were intubated successfully with GVL, and two patients were intubated with the CT. Both the GVL and the CTimproved the Cormack and Lehane view obtained at laryngoscopy, compared with the DL. Significantly high percent of patients in DL (43%) and CT (27%) required optimization maneuvers (external laryngeal pressure) compared with GVL (0%). In the CT group, 30% of the patients required laryngeal mask manipulation (for view optimization) compared with (0%) in GVL and CT groups.
Conclusion: The GlideScope® videolaryngoscope and the LMA CTrach reduced the difficulty, improved laryngoscopic views and overall success rate of tracheal Intubationto a similar extent compared with the Macintosh laryngoscope in morbidly obese patients. The GVL improved intubation time for tracheal intubation compared with the CT and DL but no patient became hypoxic with CT because of prolonged intubation time.

Keywords: GlideScope® videolaryngoscope, LMA CTrach, Macintosh laryngoscope, morbid obese patients, tracheal intubation


How to cite this article:
Yousef GT, Abdalgalil DA, Ibrahim TH. Orotracheal intubation of morbidly obese patients, comparison of GlideScope® video laryngoscope and the LMA CTrach with direct laryngoscopy. Anesth Essays Res 2012;6:174-9

How to cite this URL:
Yousef GT, Abdalgalil DA, Ibrahim TH. Orotracheal intubation of morbidly obese patients, comparison of GlideScope® video laryngoscope and the LMA CTrach with direct laryngoscopy. Anesth Essays Res [serial online] 2012 [cited 2019 May 25];6:174-9. Available from: http://www.aeronline.org/text.asp?2012/6/2/174/108304


   Introduction Top


Morbidly obese patients are at risk of difficult mask ventilation as well as intubation, and airway management is a major factor underlying morbidity and mortality related to anesthesia in such patients. [1] Morbidly obese patients are at increased risk of hypoxemia during tracheal intubation because of increased frequency of difficult intubation and insufficient oxygenation. [2] In recent years, a number of new devices have been developed to facilitate tracheal intubation in patients with difficult airways. The LMA CTrach (SEBAC, Pantin, France) was developed from the LMA Fastrach and consists of an LMA CTrach airway with fiberoptic channels and a detachable liquid crystal display viewer cum light source. The LMA CTrach enables ventilation, glottis visualization, and tracheal intubation via laryngeal mask conduit. [3] Compared with conventional laryngoscopes, the videolaryngoscope, in theory, provides a better view of the glottis. [4],[5] The GlideScope® videolaryngoscope (Verathon Medical Inc., Bothell, WA, USA) provides a high-grade, indirectclose-proximity view of the glottis on a monitor screen without aligning the oral, pharyngeal, and laryngeal axes. [4] It allows superior laryngeal visualization in both easy and difficult airways without the need for direct line of sight. [6] Therefore, this study is to determine whether the GlideScope® videolaryngoscope (GVL) and the LMA CTrach (CT) provide the best airway management, measured primarily in intubation difficulty scale (IDS) scores, time and numbers of intubation attempts and improve the intubation success rate of morbidly obese patients when compared with the direct Macintosh laryngoscope (DL) . Our hypothesis is that in comparison with the Macintosh direct laryngoscope, the GlideScope® videolaryngoscope and LMA CTrach would reduce intubation difficulty scale (IDS) scores, improve the glottic view and secondarily, will reduce the time required to achieve successful tracheal intubation in morbidly obese patients.


   Materials and Methods Top


After obtaining local research ethics board approval forthis study and written informed consent was obtained from all patients. Nienty ASA I-III morbidlyobese (BMI > 35 kg/m 2 ) consecutive adult patients were enrolled in this prospective study. The patients under went general, gynecological, and bariatric surgery Randomization to intubation with the Glide Scope® video laryngoscope (GVL group, n = 30) and the the LMA CTrach (CT group, n = 30) or Macintosh direct laryngoscope (DL group, n = 30) was performed using sealedenvelopes opened by the anesthesiologist in the operating room. All anesthesiologists performing tracheal intubations were trained in manikins in the use of the GlideScope® videolaryngoscope, the LMA CTrach and Macintosh laryngoscope. Patients with the history of hiatus hernia, symptomatic gastric reflux, gastric banding, and those with mouth opening of less than 3.5 cm (interincisor distance) were not included in the study.

All patients received a standardized general anesthetic. Standard monitoring included ECG, noninvasive arterial pressure, SpO 2 , and end-tidal CO 2 measurement. Bispectral index (BIS) (Aspect Medical Systems, Norwood, MA, USA) monitoringwas utilized in all patients. Before induction of anesthesia, all patients were given fentanyl (1-1.5 mg /kg). I.v. Propofol (2-4 mg /kg) was titrated to induce anesthesia in a dose sufficient to produce loss of verbal response. After induction of anesthesia, all patients were manually ventilated with sevoflurane (2.0-2.5%) in oxygen for 60 s. After confirmation of the adequacy of bag-mask ventilation, atracurium 0.5 mg /kg was administered. Tracheal intubationwas not performed until the BIS haddecreased below 60, and additional boluses of propofol were administered to increase depth of anesthesia if required. Three minutes after the administration of neuromuscularblock, laryngoscopy, and tracheal intubation was performed.

Airway management procedures

For the DL group) metallic reusable blades (sizes 3 and 4) were used for direct laryngoscopy. If the Cormack and Lehane grade was three or more, the use of a gum elastic bougie was used to facilitate tracheal tube insertion through the glottis. For the CT group, we followed manufacturer's recommendations to choose proper size and insertion technique of LMA CTrach (size 5 airway and 8.0 mm endotracheal tube for patients with body weigh >70 kg), then ventilation was optimized by maneuvers as the up-down maneuver or partial withdrawal. With glottis view optimized, a lubricated PVC endotracheal tube was inserted through the airway tube and railroaded in the trachea. For the GVL group, after visualization of the glottis, a stylet sloped at 90, facilitates the introduction of theendotracheal tube. The primary endpoint was the intubation difficulty score (IDS score) that was developed by Adnet and colleagues [7] is a quantitativescale incorporating multiple indices of intubation difficultythat more objectively quantifies the complexity of tracheal intubations [Table 1]. At the end of each intubation, the anesthesiologists were asked to rate subjectively overall airwaymanagement and intubation difficulty on a simple visual analoguescale (0, very easy or no difficulty; 100, major difficulty or impossible). The secondary endpoints were the time to tracheal intubation (TTI), and the rate of successful intubation, optimization maneuvers, lowest O2 saturation during intubation, esophageal intubation, upper airway morbidity as sore throat, pharyngeal bleeding, postoperative hoarseness, swallowing difficulty and dental injury. The time to intubation (TTI) was defined as the time taken from the end of the period of bag-mask ventilation, and ended when end-tidal CO 2 was detected on the monitor. Tracheal intubation was considered a failure if it could not be accomplished within three attempts or 180 s; the procedure was interrupted, facemask ventilation was provided and the patient was intubated using a different modality.
Table 1: The intubation diffi culty score

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Statistical analysis

Considering a likely difference in mean times to intubate of 10 s with a SD of 10 s, we calculated that a group size of n = 28 was needed to detect a difference with β = 0.8 and = 0.05. We therefore enrolled 30 patients per group. Statistical analysis was performed using the Mann-Whitney U-test for non-parametric and univariate ANOVA for parametric data. Duncan's post-hoc test was performed where appropriate. TTI and ease of intubation were assessed using the Mann-Whitney test. Success of tracheal intubation was analyzed using the X2 -test. These data were analyzed by using SPSS 13.0 software. Continuous data are presented as means (SD) or medians [inter-quartile range (IQR)] depending on data distribution, ordinal data are presented as medians (IQR), and categorical data are presented as number and as frequencies. All differences were considered statistically significant at P < 0.05.


   Results Top


Thirty patients were randomized to undergo tracheal intubation with each of the three devices. Patient characteristics parameters and airway variables were similar in each group [Table 2]. In the three groups, we found similar facemask ventilation difficulty and oxygenation quality before tracheal intubation was attempted. The mean TTI was 14 s faster in patients intubated with the GVL (86 s, IQR: 68-115) compared with DL (100 s, IQR; 80-150), (P < 0.05), and was 34 s faster in patients intubated with the GVL (86 s, IQR: 68-115) when compared with CT (120 s, IQR; 95-180), (P < 0.005). The mean TTI was longer in patients intubated with the CT compared with DL, (P < 0.05). The ease of intubation visual analog scale demonstrated that operators found the GVL and the CT significantly easier for intubation compared to DL. The median (IQR) VAS score for the overall Subjective intubation Difficulty was greater with DL than with GVL and CT, 25 (10-65), 10 (5-18), and 12 (1-45) respectively, (P < 0.005). There was a significant difference in the overall success rate of tracheal intubation between the GVL and CT groups compared with DL group, (P < 0.05). All 30 (100%) patients were successfully intubated with the GVL and CTdevices, compared with 24 (80%) patients with DL [Table 3]. Four patients from the six patients were intubated successfully with GVL and two patients were intubated with the CT. The Cormack-Lehane glottic view obtained at laryngoscopy was significantly better with the GVL and the CT compared with the DL. For the DL, the view was obscured in 7 of 30 patients (23%) (Grade 3 in six patients and Grade 4 in one patient), whereas for the GVL (Grade 1) and for the CT (Grade 1 in 26 patients and Grade 2 in four patients), the glottis was always clearly seen [Table 3]. One patient only had a fall in SpO 2 tobelow 92% in the GVL group and no patient in CT group compared with six patients in the DL group, (P < 0.05). A greater number of patients required optimization maneuvers (external laryngeal pressure) tofacilitate tracheal intubation with the DL (43%) and CT. (27%) compared with GVL (0%), (P< 0.005). In the CT group (30%) of the patients required laryngeal mask manipulation (for view optimization) compared with (0%) in GVL and CT groups (P < 0.001). The median (IQR) intubation difficulty scores were significantly higher with the DL {5 (2-10)} compared with GVL and CT {0 (0-1),0 (0-2)}respectively, (P < 0.001) but were not different between the G VL and CT groups [Table 3]. Details of intubation difficultyscore for the three devices are presented in [Table 4]. Easy, moderately difficult, and difficult tracheal intubation asdefined by the intubation difficulty score (0, 1-5, and.5) were met in 12, 11, and 7 patients of the DL group, respectively, while, tracheal intubation was easy in (29, 28 patients) and moderately difficult in only (1, 2 patients) in the GVL and CT groups, respectively. The rate of sore throat postoperatively was much lower in the GVLgroup (6.6 %) compared to the DL group (36.3%), (P < 0.05) and CT group (23%). Swallowing difficulty was significantly lower in the GVL group (P < 0.005) compared with the other two groups. Blood traces on the surface of the laryngoscope (pharyngeal bleeding) werefound more frequently in the DL group ((40%)) versus the GVL and CT groups (6.6 % each). There was no incidence of dental injury with any device.
Table 2: Patient characteristic parameters

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Table 3: Intubation data with the three devices

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Table 4: Intubation difficulty score for the three groups

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   Discussion Top


This study demonstrates that the Glide Scope® video laryngoscope (GVL) and The LMA CTrach (CT) both performed better than the Macintosh direct laryngoscope in morbidly obese patients but the GVL is the best. Both GVL and CT reduced the intubation difficulty score, enhanced the Cormack and Lehane glottis view, and improved Overall success rate of intubation compared with the Macintosh laryngoscope. Tracheal intubation of morbidly obese patients appears easier with the Glide Scope® videolaryngoscope and The LMA CTrach than with the Macintosh laryngoscope. Difficult tracheal intubation as defined by an intubation difficulty score of greater than 5 was recorded in eight patients of the DL group, but no patients (intubation difficulty score >5) in the GVL and CT groups. All patients of the GVL group were Cormack and Lehane Grade 1 and three only of them required a second attempt. Also 26 patients of CT group were Cormack and Lehane Grade 1 and (4) patients were Grade 2 and none of them required alternative technique of intubation, or the assistance of a second operator. In agreement with our results a previous study stated that the success rate for tracheal intubation was 100% with the LMA CTrach compared to Macintosh laryngoscope in morbidly obese patients. [8] Also the authors [9] concluded that high success rates of ventilation, glottis visualization, and tracheal intubation was found with the LMA CTrach in patients with different types of difficult airways. The Glide Scope® video laryngoscope (GVL), in agreement with our results, provided better laryngoscopic views and decreased IDS scores compared with DL. [2] It is already reported [10] that in morbidly obese patients, the use of the videolaryngoscope significantly improves the visualization of the larynx and thereby facilitates intubationthan direct laryngoscopy. Also in a study including children who are known to have a difficult airway, the use of the GlideScope videolaryngoscope, with and without laryngeal pressure, significantly improves the Cormack and Lehane grade at laryngoscopy. [11] In this study, the tracheal intubation time was significantly shorter with the Glide Scope® video laryngoscope (GVL) than with the Macintosh laryngoscope and the LMA CTrach. In our study significantly more maneuvers (Laryngeal mask manipulation ) were applied for the satisfactory ventilation and viewing of the glottis with the LMA CTrach (30%) versus 0% for GVL and DL (P < 0.05) and this explain the longer time for intubation with LMA CTrach and improved overall success rate. In morbidly obesepatients, the tracheal intubation time was significantly longer with LMA CTrach compared with the other two devices. Similar to our results; the authors had observed that, 49% of patients required manipulation of LMA CTrach resulting in increased duration of tracheal intubation by 57 seconds as compared to direct laryngoscopy (DL) in their study [12] but oxygenation was of better quality in patients managed with LMACTrach than direct laryngoscopy (DL). Also in their study evaluating LMACTrach, [13] the authors observed that, manipulations required in 63.3% cases with LMA CTrach. Also recently the authors [14] found that the median (IQR) total time taken for tracheal intubation in morbidly obese patients with the LMA CTrach was 128 (98-221) s which is nearly similar to our results. In contrast to our results, a previous study [2] found that intubation of morbidly obese patients with GVL was slightly slower than with DL but the increased intubation time was of no clinical consequence as no patients became hypoxemic. In the present study, nine patients needed cricoid pressure application for viewing of the glottis with the LMACTrach and this was in agreement with others. [15],[16] In our study, an absolute risk reduction of (30%) in the incidence of postoperative sore throat in GVL compared to DL and (16%) compared to CT was demonstrated. The rate of sore throat with GVL and CT groups postoperatively was less than in other studies investigating the devices, [14],[17] respectively. We have one limitation in our study which is that the anesthetist is not blind to the device used and this was practically impossible.

In conclusion, The GlideScope videolaryngoscope and theLMACTrach reduced the difficulty, improved laryngoscopic views and overall success rate of tracheal Intubationto a similar extent compared with the Macintosh direct laryngoscope, in case of a difficult airway in morbidly obese patients . The GlideScope videolaryngoscope improved intubation time for tracheal intubation with less upper airway morbidity compared with the LMACTrach and Macintosh direct laryngoscope. The increased intubation time with LMACTrach was of no clinical consequence as no patients became hypoxemic.

 
   References Top

1.El-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD. Preoperative airway assessment: Predictive value of a multivariate risk index. Anesth Analg 1996;82:1197-204.  Back to cited text no. 1
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2.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;55:1090-7.  Back to cited text no. 2
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3.Liu EH, Goy RW, Chen FG. The LMA CTrach, a new laryngeal mask airway for endotracheal intubation under vision: Evaluation in 100 patients. Br J Anaesth 2006;96:396-40.  Back to cited text no. 3
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4.Cooper RM, Pacey JA, Bishop MJ, McCluskey SA. Early clinical experience with a new videolaryngoscope (Glidescope) in 728 patients. Can J Anaesth 2005;52:191-8.  Back to cited text no. 4
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6.Xue F, Zhang G, Liu J, Li X, Sun H, Wang X, et al. A clinical assessment of the Glidescope Video-laryngoscope in nasotracheal intubation with general anesthesia. J Clin Anesth 2006;18:611-5.  Back to cited text no. 6
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7.Adnet F, Borron SW, Racine SX. The intubation difficulty scale (IDS): Proposal and evaluation of a new score characterizing the complexity of endotracheal intubation. Anesthesiology 1997;87:1290-7.  Back to cited text no. 7
    
8.Dhonneur G, Abdi W, Ndoko SK, Amathieu R, Risk N, El Housseini L, et al. Video-assisted versus conventional tracheal intubation in morbidly obese patients. Obes Surg 2009;19:1096-101.  Back to cited text no. 8
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9.Eugene HL, Regina W, Allan JG. The LMACTrach in patients with difficult airways Anesthesiology 2009;110:941-3.  Back to cited text no. 9
    
10.Marrel J, Blanc C, Frascarolo P, Magnusson L. Videolaryngoscopy improves intubation condition in morbidly obese patients. Eur J Anaesthesiol 2007;24:1045-9.  Back to cited text no. 10
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11.Karsli C, ArmstrongJ, John J. A comparison between the GlideScope VideoLaryngoscope and direct laryngoscope in paediatric patients with difficult airways - a pilot study. Anaesthesia 2010;65:353-7.  Back to cited text no. 11
    
12.Dhonneur G, Ndoko SK, Yavchitz1 A, Foucrier A, Fessenmeyer C, Pollian C, et al. Tracheal intubation of morbidly obese patients: LMA CTrach vs direct laryngoscopy. Br J Anaesth 2006;97:742-5.  Back to cited text no. 12
    
13.Timmermann A, Russo S, Graf BM. Evaluation of the CTrach: An intubating LMA with integrated fibre optic system. Br J Anaesth 2006;96:516-21.  Back to cited text no. 13
    
14.Arslan ZI, Özdamar D, Yildiz TS, Solak ZM, Toker K. Tracheal intubation in morbidly obese patients: A comparison of the intubating laryngeal mask airway and laryngeal mask airway CTrach. Anaesthesia 2012;67:261-5.  Back to cited text no. 14
    
15.Swadia N 1V, Mamta G. Our preliminary experience with the lmactrach. Indian J Anaesth 2009;53:312-7.  Back to cited text no. 15
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16.Dhonneur G, Ndoko SK. Tracheal intubation with the LMA CTrach: Need for cricoid pressure. Br J Anaesth 2007;99:749-50.  Back to cited text no. 16
    
17.Lange M, Frommer M, Redel A. Comparison of the Glidescope and Airtraq optical laryngoscopes in patients undergoing direct microlaryngoscopy. Anaesthesia 2009;64:323-8.  Back to cited text no. 17
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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