- Email: [email protected]
Bonfils fiberscope vs GlideScope for awake intubation in morbidly obese patients with expected difficult airways
Journal of Clinical Anesthesia (2016) 32, 101–105
Original contribution
Bonfils fiberscope vs GlideScope for awake intubation in morbidly obese patients with expected difficult airways☆,☆☆ Mahmoud Nassar MD (Lecturer) a,b,⁎, Ola M. Zanaty MD (Assistant Professor) a , Mohamed Ibrahim MD (Professor, Consultant) a,b a
Faculty of Medicine, University of Alexandria, Alexandria, Egypt Ahmadi Hospital, Kuwait Oil Company Hospital, Ahmadi, Kuwait
b
Received 6 January 2015; revised 21 July 2015; accepted 12 January 2016
Keywords: Bonfils fiberscope; GlideScope; Awake intubation; Morbidly obese; Difficult airway; Bariatric surgery
Abstract Study Objective: To assess the efficacy of both Bonfils and GlideScope in obese patient with difficult airways for bariatric surgery using awake intubation. Design: Comparative study. Setting: Operating room. Patients: The study was carried out on 60 patients, for laparoscopic bariatric surgery, after approval of the Medical Ethics Committee and having an informed written consent from each patient. Patients were randomly categorized into 2 equal groups 30 patients in each group. Interventions: Awake intubation with either Retromolar Bonfils or GlideScope. Measurements: Time to visualize the laryngeal inlet, time of intubation, time of scope manipulation, success rate at each attempt, the lowest oxygen saturation, hemodynamic parameters, and any complication. Main Results: Regarding intubation criteria, GlideScope achieves shorter times compared with Retromolar for visualization of the vocal cords and intubation, in addition to less intubation attempts, but both without a statistically significant difference. Retromolar shows better patient satisfaction than does GlideScope, with statistically significant difference. Conclusions: Both Bonfils fiberscope and the GlideScope can be successfully used for awake intubation in morbidly obese patients with expected difficult airways. Bonfils intubating fiberscope was more tolerated by patients with statistical difference; on the other hand, GlideScope provided shorter intubation time and less intubation attempts but not statistically significant. © 2016 Elsevier Inc. All rights reserved.
☆ Conflict of interest: No actual or potential conflict of interest in relation to this article exists. ☆☆ Place of the study: Ahmadi Hospital, Kuwait Oil Company, Kuwait. ⁎ Corresponding author at: Lecturer of Anesthesia and Surgical Intensive Care, Faculty of Medicine, University of Alexandria, Alexandria, Egypt. Tel.: + 20 122 3737494. E-mail addresses: [email protected], [email protected] (M. Nassar).
http://dx.doi.org/10.1016/j.jclinane.2016.01.004 0952-8180/© 2016 Elsevier Inc. All rights reserved.
1. Introduction In spite of the development of a lot of airway devices in the past 2 decades, tracheal intubation problems were the most common primary airway problems [1]. Difficult airway
102 as defined by the American Society of Anesthesiologists is problems with face mask ventilation, tracheal intubation, or placement and use of a supraglottic airway [2]. Because obesity is an independent risk factor for problems with face mask ventilation, so many morbidly obese patients would have a difficult airway [3–5]. There are potentially more challenging patients to intubate as a subtype of obese patients, for example, the extremely obese men, with high Mallampati scores, wide neck, and probably obstructive sleep apnea [6]. The Bonfils Retromolar is one of many new devices that have been developed to assist anesthetists dealing with difficult airways [7,8]. The coverage of the Bonfils by hard metal and its fixed end which is slightly curved upward may be the causes that make it easy to be used. Bonfils could be used in emergencies because it needs a short time for preparations [9,10]. GlideScope improves the laryngeal view as one of its advantages [11–13] due to the blade angle of 60° which is designed to improve the glottic view without the need of alignment of the oral, pharyngeal, and tracheal axes and also without adding additional lifting force [14,15]. The aim of the study is to compare Retromolar Bonfils vs GlideScope in morbidly obese patients with expected difficult airway, undergoing laparoscopic bariatric surgery.
2. Materials and methods The present study was carried out in Kuwait Oil Company Hospital, after approval of the Medical Ethics Committee on 60 patients. They were randomly categorized according to table technique into 2 equal groups (30 patients in each group) for awake intubation with either Retromolar Bonfils or GlideScope. Patients were American Society of Anesthesiologists statuses I and II, older than 20 years, and undergoing laparoscopic Bariatric surgery. The inclusion criteria were a body mass index greater than 40 kg/m2 and expected difficult airway defined as Wilson risk score N 2 [16,17]. Patients who were uncooperative, were mentally abnormal, had mouth opening of less than 4 cm, or were having any contraindications with the drugs used were excluded from the study. The devices used in the present study were Bonfils Retromolar and GlideScope video laryngoscope. Bonfils intubation endoscope 5,0X 40 was manufactured by Karl Storz, Germany. Bonfils was used with Storz tele pack X monitor (Figs. 1 and 2). GlideScope (portable GVL) was manufactured by Verathon Medical (Canada) ULC (Fig. 3). The technique of intubation was explained to the patient during the preoperative visit and informed written consent was obtained. In an operation theater, patients were monitored by using (Datex-Ohmeda S/5 ADU Care Station) for heart rate, mean arterial blood pressure, and arterial oxygen saturation. The patient was placed in the sniffing position; nasal cannula was used to give O2 of 4 L/min. Remifentanil was administered as a bolus 1 μg/kg and then
M. Nassar et al.
Fig. 1
Bonfils Retromolar with Storz tele pack X monitor.
as an infusion according to Ramsay Sedation Score to reach a sedation score level of 3. Awake intubation was done by applying surface analgesia to the airway. Afterward, xylometazoline spray as a nasal decongestant, lidocaine 10% spray, and 2% gel were used to block ophthalmic and maxillary divisions of trigeminal nerves for preparation of the nasal passage and nasopharynx. Regarding the oropharynx, the glossopharyngeal nerve was blocked by applying a piece of gauze with lidocaine 2% gel to the base of anterior tonsilar pillars. The larynx, in the form of superior laryngeal nerve, was blocked by spraying lidocaine with atomizer while holding the tongue out of the mouth with a piece of gauze. Regarding the trachea, recurrent laryngeal nerve was blocked by the “spray as you go” technique. A dose of 4 mg/kg lidocaine was maximally allowed to avoid toxicity. If gagging or coughing was encountered during the trial of intubation, remifentanil infusion was increased, with waiting time of 1.5 minutes, then another trial for intubation was done. The intubation was done by either of the 2 doctors who are experienced in both devices. In the Bonfils group, the midline technique was used, behind the tongue till the glottic view appeared, just before the vocal cords were reached; the endotracheal tube threaded over it, and jaw thrust or chin lift
Fig. 2
Bonfils Retromolar.
103
4. Sample size calculation Previous study showed intubation time with awake GlideScope to be 73.6 ± 31.1 seconds [18]. In order to reach 80% power and an α error of 0.05 to detect a difference in intubation time of 45 seconds or more between the 2 techniques in the assumption of an SD of 60 seconds, the sample size was calculated to be 60 patients, 30 in each group.
5. Statistical analysis Data were statistically analyzed using the Statistical Package for Social Sciences (SPSS) computer software version 15. Numerical data were presented as mean ± SD and categorical data as χ2 and Fisher exact tests. Student t test was used for comparison between groups as regard quantitative data. A difference with P value b .05 was considered statistically significant.
Fig. 3
GlideScope with stylet.
was used to help the intubation. In the GlideScope group, midline approach was used until reaching the epiglottis, lifting it until the glottic view became clear, and then the endotracheal tube over the special stylet for the GlideScope was inserted. If during the intubation trial, there was a desaturation less than 92% or inability to see the vocal cord, it was considered as unsuccessful, and the procedure was considered as a failure after the third attempt [16,17].
3. Measurements Time to visualize the laryngeal inlet was defined as the time from scope introduction till visualization of the laryngeal inlet. Time of intubation was defined as the time from the scope entry till confirmation of correct endotracheal tube position by end-tidal capnography during the last successful attempt. Time of scope manipulation was defined as the time during all attempts (time total) till endotracheal tube confirmation of correct position was calculated. Success rate at each attempt was % of success at first, second, or third attempt). The lowest oxygen saturation recorded during the intubation was recorded. Hemodynamic parameters (heart rate, mean arterial pressure) and any complication during the intubation were documented. Hoarseness of voice and sore throat were checked on the first postoperative day. Patient satisfaction was assessed according to numerical rating scale from 0 to 10 (0, not satisfied; 10, completely satisfied). The primary outcome was the time to intubate, and secondary outcome was the rest of the parameters.
6. Results The present study was carried on 60 patients, 30 patients in each group. There were no statistical differences regarding demographic data or Wilson score (Table 1). Regarding intubation criteria, both GlideScope and Retromolar achieved comparable time for the intubation (53 ± 18 seconds vs 58 ± 16 seconds), respectively, with no statistically significant difference. Less intubation attempts for GlideScope were observed, but also with no statistically significant difference. Retromolar showed better patient satisfaction than did GlideScope with statistically significant difference (P = .032*; Table 2). There were no statistically significant differences between the 2 studied groups regarding hemodynamic (Table 3).
7. Discussion This study was done to compare Bonfils vs GlideScope in obese patients with difficult airways for Bariatric surgery Table 1
Demographic data
Age (y) Sex (male/female) Weight (kg) Height (cm) BMI (kg/m2) Wilson score
Retromolar Bonfils GlideScope (n = 30) (n = 30)
P
45 ± 14 12:18 136.68 ± 23 170.14 ± 9.3 47.14 ± 4.37 4.2 ± 0.952
.529 .602 .368 .054 .663 .689
47 ± 10 14:16 131.14 ± 24.35 165.5 ± 9 47.89 ± 8.3 4.3 ± 0.98
104
M. Nassar et al.
Table 2
Intubation criteria
Time to visualize the laryngeal inlet (s) Time for intubation (s) Time of scope manipulation during all attempts (s) Success rate at each attempt 1st attempt 2nd attempt 3rd attempt The lowest arterial oxygen saturation Hoarseness and/or sore throat Patient satisfaction
Retromolar Bonfils (n = 30)
GlideScope (n = 30)
P
20 ± 6 58 ± 16 93 ± 19
17 ± 9 53 ± 18 89 ± 22
.137 .257 .457
22 (73.33%) 6 (20%) 2 (6.67%) 92% ± 3 3 (10%) 5±4
26 (86.67%) 4 (13.33%) 0 93 ± 3 5 (16.67%) 3±3
χ2, .197 Fisher, .731 Fisher, .492 .202 χ2, .448 .032 ⁎
⁎ P is less than 0.05, statistically significant difference.
using awake intubation. Both the Bonfils fiberscope and the GlideScope were successfully used for awake intubation. Regarding GlideScope, it showed less intubation attempts compared with Retromolar, but not statistically significant. Regarding patient satisfaction, Retromolar showed better patient satisfaction than did GlideScope, with statistically significant difference. Awake intubation by Bonfils Retromolar fiberscope was used successfully for intubation of 5 patients with expected difficult airways. Some of the advantages of this device are that it easily navigates through the soft tissue, lifts the airway structure, and is more durable, affordable, and easy to be cleaned [7]. The Bonfils fiberscope is one of the most promising devices to assist awake intubation in patients with difficult airways because it is well tolerated and highly successful, even if performed by operators in training [8]. Awake tracheal intubation with Bonfils in patients with predicted difficult airways was successful, effective, safe, and well tolerated by almost all patients, with a 93.9% rate [19]. On the other hand, the Bonfils fiberscope showed significant improvement in laryngeal view in comparison to the GlideScope, in addition to shorter time for intubation than the GlideScope (36 ± 8 and 49 ± 12 seconds, respectively; P b 0.001) in the study by Kaufmann et al
Table 3
Hemodynamic data
HR (beats/min) • Baseline • After remifentanil • Just after intubation MAP (mm Hg) • Baseline • After remifentanil • Just after intubation
Retromolar Bonfils (n = 30)
GlideScope (n = 30)
P
75 ± 12 65 ± 8 77 ± 9
80 ± 15 67 ± 9 79 ± 7
.157 .363 .344
80 ± 11 70 ± 6 83 ± 7
84 ± 9 72 ± 5 86 ± 8
.128 .167 .128
HR = heart rate; MAP = mean arterial blood pressure.
[20]. These differences from the present study may be attributed to the fact that it was done on children and it dealt with normal airways. A study of 4 patients with successful intubation with GlideScope after failure of awake fiberoptic after adequate sedation and airway blocks, because of macroglossia showed that these patients were morbid obese with expected difficult airway. Glidescopic manipulations and intubation were done with minimal patient discomfort [21]. A study compared 4 devices: GlideScope, Bonfils, and CTrach with the Macintosh laryngoscope in a normal and difficult airway simulator. As regards first-attempt success rate, it was high in all devices compared with 100% in GlideScope for all participants in both conditions of the simulator. It was found by most of the participants that the GlideScope was easier to use compared with the other devices and it was the preferred one in the simulated difficult airway, regardless of previous experience of the participants [22]. Another study concluded that GlideScope can be used as a useful alternative to fiberoptic in morbidly obese patients with expected difficult airway [18]. Intubation time was 73.6 ± 31.1 seconds for GlideScope. Successful intubation rate on the first attempt was 80.6% with GlideScope. On the opposite side, a case report of a 125-kg patient showed failed awake GlideScope after 4 mg midazolam. Although it was lengthy, a trial of awake fiberoptic intubation was done for that patient and succeeded. The patient recalls the discomfort of the GlideScope but not any of the fiberoptic; this may be because of the inadequate sedation and inadequate airway block. It was concluded that awake GlideScope could be introduced into the training of emergency department doctors. It is presented as an alternative to awake fiberoptic, as it needs less training and skills [21].
8. Conclusion For morbidly obese patients with predicted difficult airway, the Retromolar Bonfils fiberscope and the GlideScope can be successfully used for awake intubation. Bonfils
105 intubating fiberscope was more tolerated by the patients. GlideScope provided less intubation attempts, but not of statistical significance.
Recommendation Both GlideScope and Bonfils Retromolar can be used in the management of difficult airways in morbidly obese patients. Hence, the regular use of both devices in patients with normal airway is recommended to gain good experience while managing patients with difficult intubation.
References [1] Cook TM, Woodal N, Frek C. Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth 2011;106:617-31. [2] Apfelbaum JL, Hagberg CA, Caplan RA. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2013;118:251-70. [3] Langeron O, Masso E, Huraux C, Guggiari M, Bianchi A, Coriat P, et al. Prediction of difficult mask ventilation. Anesthesiology 2000;92:1229-36. [4] El-Orbany M, Woehlck HJ. Difficult mask ventilation. Anesth Analg 2009;109:1870-80. [5] Soens MA, Birnbach DJ, Ranasinghe JS, van Zundert A. Obstetric anesthesia for the obese and morbidly obese patient: an ounce of prevention is worth more than a pound of treatment. Acta Anaesthesiol Scand 2008;52:6-19. [6] Brodsky JB, Lemmens HJM, Vierra M, Saidman LJ. Morbid obesity and tracheal intubation. Anesth Analg 2002;94:732-6. [7] Abramson SI, Holmes AA. Awake insertion of the Bonfils Retromolar intubation fiberscope in five patients with anticipated difficult airways. Anesth Analg 2008;106(4):1215-7. [8] Corbanese U, Possamai C. Awake intubation with the Bonfils fibrescope in patients with difficult airway. Eur J Anaesthesiol 2009;26(10):837-41.
[9] Halligan M, Charters P. A clinical evaluation of the Bonfils intubation fibrescope. Anaesthesia 2003;58:1087-91. [10] Bein B, Yan M, Tonner PH, Scholz J, Steinfath M, Dorges V. Tracheal intubation using the Bonfils intubation fibrescope after failed direct laryngoscopy. Anaesthesia 2004;59:1207-9. [11] 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. [12] Teoh WH, Saxena S, Shah MK, Sia AT. Comparison of three videolaryngoscopes: Pentax Airway Scope, C-MAC, GlideScope vs. the Macintosh laryngoscope for tracheal intubation. Anaesthesia 2010; 65:1126-32. [13] Andersen LH. GlideScope videolaryngoscope vs. Macintosh direct laryngoscope for intubation of morbidly obese patients: a randomized trial. Acta Anaesthesiol Scand 2011;55:1090-7. [14] Karsli C, Armstrong J, John J. A comparison between the GlideScope video laryngoscope and direct laryngoscope in paediatric patients with difficult airways—a pilot study. Anaesthesia 2010;65(4):353-7. [15] Lange M, Frommer M, Redel A. Comparison of the GlideScope and Airtraq optical laryngoscopes in patients undergoing direct microlaryngoscopy. Anaesthesia 2009;64:323-8. [16] Wilson ME, Spiegelhalter D, Robertson J, Lesser I. Predicting difficult intubation. Br J Anaesth 1988;61:211-6. [17] Gupta S, Sharma R, Jain D. Airway assessment: predictors of difficult airway. Indian J Anaesth 2005;49(4):257-62. [18] Abdellatif AA, Ali MA. GlideScope® videolaryngoscope versus flexible fiberoptic bronchoscope for awake intubation of morbidly obese patient with predicted difficult intubation. Middle East J Anaesthesiol 2014;22(4):385-92. [19] Mazères JE, Lefranc A, Cropet C, Steghens A, Bachmann P, Pérol O, et al. Evaluation of the Bonfils intubating fibrescope for predicted difficult intubation in awake patients with ear, nose and throat cancer. Eur J Anaesthesiol 2011;28(9):646-50. [20] Kaufmann J, Laschat M, Hellmich M, Wappler F. A randomized controlled comparison of the Bonfils fiberscope and the GlideScope Cobalt AVL video laryngoscope for visualization of the larynx and intubation of the trachea in infants and small children with normal airways. Paediatr Anaesth 2013;23(10):913-9. [21] Alexander HS, Steven PM, Corey S. The awake Glidoscope intubation: an additional alternative to the difficult intubation. Middle East J Anaesthesiol 2010;20(5):743-7. [22] Powell L, Anderzejowski J, Taylor R, Turnbull D. Comparison of the performance of four laryngoscopes in a high-fidelity simulator using normal and difficult airway. Br J Anaesth 2009;103(5):755-60.
Original contribution
Bonfils fiberscope vs GlideScope for awake intubation in morbidly obese patients with expected difficult airways☆,☆☆ Mahmoud Nassar MD (Lecturer) a,b,⁎, Ola M. Zanaty MD (Assistant Professor) a , Mohamed Ibrahim MD (Professor, Consultant) a,b a
Faculty of Medicine, University of Alexandria, Alexandria, Egypt Ahmadi Hospital, Kuwait Oil Company Hospital, Ahmadi, Kuwait
b
Received 6 January 2015; revised 21 July 2015; accepted 12 January 2016
Keywords: Bonfils fiberscope; GlideScope; Awake intubation; Morbidly obese; Difficult airway; Bariatric surgery
Abstract Study Objective: To assess the efficacy of both Bonfils and GlideScope in obese patient with difficult airways for bariatric surgery using awake intubation. Design: Comparative study. Setting: Operating room. Patients: The study was carried out on 60 patients, for laparoscopic bariatric surgery, after approval of the Medical Ethics Committee and having an informed written consent from each patient. Patients were randomly categorized into 2 equal groups 30 patients in each group. Interventions: Awake intubation with either Retromolar Bonfils or GlideScope. Measurements: Time to visualize the laryngeal inlet, time of intubation, time of scope manipulation, success rate at each attempt, the lowest oxygen saturation, hemodynamic parameters, and any complication. Main Results: Regarding intubation criteria, GlideScope achieves shorter times compared with Retromolar for visualization of the vocal cords and intubation, in addition to less intubation attempts, but both without a statistically significant difference. Retromolar shows better patient satisfaction than does GlideScope, with statistically significant difference. Conclusions: Both Bonfils fiberscope and the GlideScope can be successfully used for awake intubation in morbidly obese patients with expected difficult airways. Bonfils intubating fiberscope was more tolerated by patients with statistical difference; on the other hand, GlideScope provided shorter intubation time and less intubation attempts but not statistically significant. © 2016 Elsevier Inc. All rights reserved.
☆ Conflict of interest: No actual or potential conflict of interest in relation to this article exists. ☆☆ Place of the study: Ahmadi Hospital, Kuwait Oil Company, Kuwait. ⁎ Corresponding author at: Lecturer of Anesthesia and Surgical Intensive Care, Faculty of Medicine, University of Alexandria, Alexandria, Egypt. Tel.: + 20 122 3737494. E-mail addresses: [email protected], [email protected] (M. Nassar).
http://dx.doi.org/10.1016/j.jclinane.2016.01.004 0952-8180/© 2016 Elsevier Inc. All rights reserved.
1. Introduction In spite of the development of a lot of airway devices in the past 2 decades, tracheal intubation problems were the most common primary airway problems [1]. Difficult airway
102 as defined by the American Society of Anesthesiologists is problems with face mask ventilation, tracheal intubation, or placement and use of a supraglottic airway [2]. Because obesity is an independent risk factor for problems with face mask ventilation, so many morbidly obese patients would have a difficult airway [3–5]. There are potentially more challenging patients to intubate as a subtype of obese patients, for example, the extremely obese men, with high Mallampati scores, wide neck, and probably obstructive sleep apnea [6]. The Bonfils Retromolar is one of many new devices that have been developed to assist anesthetists dealing with difficult airways [7,8]. The coverage of the Bonfils by hard metal and its fixed end which is slightly curved upward may be the causes that make it easy to be used. Bonfils could be used in emergencies because it needs a short time for preparations [9,10]. GlideScope improves the laryngeal view as one of its advantages [11–13] due to the blade angle of 60° which is designed to improve the glottic view without the need of alignment of the oral, pharyngeal, and tracheal axes and also without adding additional lifting force [14,15]. The aim of the study is to compare Retromolar Bonfils vs GlideScope in morbidly obese patients with expected difficult airway, undergoing laparoscopic bariatric surgery.
2. Materials and methods The present study was carried out in Kuwait Oil Company Hospital, after approval of the Medical Ethics Committee on 60 patients. They were randomly categorized according to table technique into 2 equal groups (30 patients in each group) for awake intubation with either Retromolar Bonfils or GlideScope. Patients were American Society of Anesthesiologists statuses I and II, older than 20 years, and undergoing laparoscopic Bariatric surgery. The inclusion criteria were a body mass index greater than 40 kg/m2 and expected difficult airway defined as Wilson risk score N 2 [16,17]. Patients who were uncooperative, were mentally abnormal, had mouth opening of less than 4 cm, or were having any contraindications with the drugs used were excluded from the study. The devices used in the present study were Bonfils Retromolar and GlideScope video laryngoscope. Bonfils intubation endoscope 5,0X 40 was manufactured by Karl Storz, Germany. Bonfils was used with Storz tele pack X monitor (Figs. 1 and 2). GlideScope (portable GVL) was manufactured by Verathon Medical (Canada) ULC (Fig. 3). The technique of intubation was explained to the patient during the preoperative visit and informed written consent was obtained. In an operation theater, patients were monitored by using (Datex-Ohmeda S/5 ADU Care Station) for heart rate, mean arterial blood pressure, and arterial oxygen saturation. The patient was placed in the sniffing position; nasal cannula was used to give O2 of 4 L/min. Remifentanil was administered as a bolus 1 μg/kg and then
M. Nassar et al.
Fig. 1
Bonfils Retromolar with Storz tele pack X monitor.
as an infusion according to Ramsay Sedation Score to reach a sedation score level of 3. Awake intubation was done by applying surface analgesia to the airway. Afterward, xylometazoline spray as a nasal decongestant, lidocaine 10% spray, and 2% gel were used to block ophthalmic and maxillary divisions of trigeminal nerves for preparation of the nasal passage and nasopharynx. Regarding the oropharynx, the glossopharyngeal nerve was blocked by applying a piece of gauze with lidocaine 2% gel to the base of anterior tonsilar pillars. The larynx, in the form of superior laryngeal nerve, was blocked by spraying lidocaine with atomizer while holding the tongue out of the mouth with a piece of gauze. Regarding the trachea, recurrent laryngeal nerve was blocked by the “spray as you go” technique. A dose of 4 mg/kg lidocaine was maximally allowed to avoid toxicity. If gagging or coughing was encountered during the trial of intubation, remifentanil infusion was increased, with waiting time of 1.5 minutes, then another trial for intubation was done. The intubation was done by either of the 2 doctors who are experienced in both devices. In the Bonfils group, the midline technique was used, behind the tongue till the glottic view appeared, just before the vocal cords were reached; the endotracheal tube threaded over it, and jaw thrust or chin lift
Fig. 2
Bonfils Retromolar.
103
4. Sample size calculation Previous study showed intubation time with awake GlideScope to be 73.6 ± 31.1 seconds [18]. In order to reach 80% power and an α error of 0.05 to detect a difference in intubation time of 45 seconds or more between the 2 techniques in the assumption of an SD of 60 seconds, the sample size was calculated to be 60 patients, 30 in each group.
5. Statistical analysis Data were statistically analyzed using the Statistical Package for Social Sciences (SPSS) computer software version 15. Numerical data were presented as mean ± SD and categorical data as χ2 and Fisher exact tests. Student t test was used for comparison between groups as regard quantitative data. A difference with P value b .05 was considered statistically significant.
Fig. 3
GlideScope with stylet.
was used to help the intubation. In the GlideScope group, midline approach was used until reaching the epiglottis, lifting it until the glottic view became clear, and then the endotracheal tube over the special stylet for the GlideScope was inserted. If during the intubation trial, there was a desaturation less than 92% or inability to see the vocal cord, it was considered as unsuccessful, and the procedure was considered as a failure after the third attempt [16,17].
3. Measurements Time to visualize the laryngeal inlet was defined as the time from scope introduction till visualization of the laryngeal inlet. Time of intubation was defined as the time from the scope entry till confirmation of correct endotracheal tube position by end-tidal capnography during the last successful attempt. Time of scope manipulation was defined as the time during all attempts (time total) till endotracheal tube confirmation of correct position was calculated. Success rate at each attempt was % of success at first, second, or third attempt). The lowest oxygen saturation recorded during the intubation was recorded. Hemodynamic parameters (heart rate, mean arterial pressure) and any complication during the intubation were documented. Hoarseness of voice and sore throat were checked on the first postoperative day. Patient satisfaction was assessed according to numerical rating scale from 0 to 10 (0, not satisfied; 10, completely satisfied). The primary outcome was the time to intubate, and secondary outcome was the rest of the parameters.
6. Results The present study was carried on 60 patients, 30 patients in each group. There were no statistical differences regarding demographic data or Wilson score (Table 1). Regarding intubation criteria, both GlideScope and Retromolar achieved comparable time for the intubation (53 ± 18 seconds vs 58 ± 16 seconds), respectively, with no statistically significant difference. Less intubation attempts for GlideScope were observed, but also with no statistically significant difference. Retromolar showed better patient satisfaction than did GlideScope with statistically significant difference (P = .032*; Table 2). There were no statistically significant differences between the 2 studied groups regarding hemodynamic (Table 3).
7. Discussion This study was done to compare Bonfils vs GlideScope in obese patients with difficult airways for Bariatric surgery Table 1
Demographic data
Age (y) Sex (male/female) Weight (kg) Height (cm) BMI (kg/m2) Wilson score
Retromolar Bonfils GlideScope (n = 30) (n = 30)
P
45 ± 14 12:18 136.68 ± 23 170.14 ± 9.3 47.14 ± 4.37 4.2 ± 0.952
.529 .602 .368 .054 .663 .689
47 ± 10 14:16 131.14 ± 24.35 165.5 ± 9 47.89 ± 8.3 4.3 ± 0.98
104
M. Nassar et al.
Table 2
Intubation criteria
Time to visualize the laryngeal inlet (s) Time for intubation (s) Time of scope manipulation during all attempts (s) Success rate at each attempt 1st attempt 2nd attempt 3rd attempt The lowest arterial oxygen saturation Hoarseness and/or sore throat Patient satisfaction
Retromolar Bonfils (n = 30)
GlideScope (n = 30)
P
20 ± 6 58 ± 16 93 ± 19
17 ± 9 53 ± 18 89 ± 22
.137 .257 .457
22 (73.33%) 6 (20%) 2 (6.67%) 92% ± 3 3 (10%) 5±4
26 (86.67%) 4 (13.33%) 0 93 ± 3 5 (16.67%) 3±3
χ2, .197 Fisher, .731 Fisher, .492 .202 χ2, .448 .032 ⁎
⁎ P is less than 0.05, statistically significant difference.
using awake intubation. Both the Bonfils fiberscope and the GlideScope were successfully used for awake intubation. Regarding GlideScope, it showed less intubation attempts compared with Retromolar, but not statistically significant. Regarding patient satisfaction, Retromolar showed better patient satisfaction than did GlideScope, with statistically significant difference. Awake intubation by Bonfils Retromolar fiberscope was used successfully for intubation of 5 patients with expected difficult airways. Some of the advantages of this device are that it easily navigates through the soft tissue, lifts the airway structure, and is more durable, affordable, and easy to be cleaned [7]. The Bonfils fiberscope is one of the most promising devices to assist awake intubation in patients with difficult airways because it is well tolerated and highly successful, even if performed by operators in training [8]. Awake tracheal intubation with Bonfils in patients with predicted difficult airways was successful, effective, safe, and well tolerated by almost all patients, with a 93.9% rate [19]. On the other hand, the Bonfils fiberscope showed significant improvement in laryngeal view in comparison to the GlideScope, in addition to shorter time for intubation than the GlideScope (36 ± 8 and 49 ± 12 seconds, respectively; P b 0.001) in the study by Kaufmann et al
Table 3
Hemodynamic data
HR (beats/min) • Baseline • After remifentanil • Just after intubation MAP (mm Hg) • Baseline • After remifentanil • Just after intubation
Retromolar Bonfils (n = 30)
GlideScope (n = 30)
P
75 ± 12 65 ± 8 77 ± 9
80 ± 15 67 ± 9 79 ± 7
.157 .363 .344
80 ± 11 70 ± 6 83 ± 7
84 ± 9 72 ± 5 86 ± 8
.128 .167 .128
HR = heart rate; MAP = mean arterial blood pressure.
[20]. These differences from the present study may be attributed to the fact that it was done on children and it dealt with normal airways. A study of 4 patients with successful intubation with GlideScope after failure of awake fiberoptic after adequate sedation and airway blocks, because of macroglossia showed that these patients were morbid obese with expected difficult airway. Glidescopic manipulations and intubation were done with minimal patient discomfort [21]. A study compared 4 devices: GlideScope, Bonfils, and CTrach with the Macintosh laryngoscope in a normal and difficult airway simulator. As regards first-attempt success rate, it was high in all devices compared with 100% in GlideScope for all participants in both conditions of the simulator. It was found by most of the participants that the GlideScope was easier to use compared with the other devices and it was the preferred one in the simulated difficult airway, regardless of previous experience of the participants [22]. Another study concluded that GlideScope can be used as a useful alternative to fiberoptic in morbidly obese patients with expected difficult airway [18]. Intubation time was 73.6 ± 31.1 seconds for GlideScope. Successful intubation rate on the first attempt was 80.6% with GlideScope. On the opposite side, a case report of a 125-kg patient showed failed awake GlideScope after 4 mg midazolam. Although it was lengthy, a trial of awake fiberoptic intubation was done for that patient and succeeded. The patient recalls the discomfort of the GlideScope but not any of the fiberoptic; this may be because of the inadequate sedation and inadequate airway block. It was concluded that awake GlideScope could be introduced into the training of emergency department doctors. It is presented as an alternative to awake fiberoptic, as it needs less training and skills [21].
8. Conclusion For morbidly obese patients with predicted difficult airway, the Retromolar Bonfils fiberscope and the GlideScope can be successfully used for awake intubation. Bonfils
105 intubating fiberscope was more tolerated by the patients. GlideScope provided less intubation attempts, but not of statistical significance.
Recommendation Both GlideScope and Bonfils Retromolar can be used in the management of difficult airways in morbidly obese patients. Hence, the regular use of both devices in patients with normal airway is recommended to gain good experience while managing patients with difficult intubation.
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