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The use of the GlideScope® for tracheal intubation in patients with halo vest
Acta Anaesthesiologica Taiwanica 49 (2011) 88e90
Contents lists available at SciVerse ScienceDirect
Acta Anaesthesiologica Taiwanica journal homepage: www.e-aat.com
Original Article
The use of the GlideScopeÒ for tracheal intubation in patients with halo vest Shen-Jer Huang1, Chia-Lin Lee1, Po-Kai Wang1, Pei-Chin Lin1, Hsien-Yong Lai2 * 1 2
Department of Anesthesiology, Buddhist Tzu-Chi General Hospital, Hualien, Taiwan, R.O.C. Department of Medical Education and Research, Mennonite Christian Hospital, Hualien, Taiwan, R.O.C.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 July 2011 Received in revised form 9 August 2011 Accepted 12 August 2011
Objective: GlideScopeÒ provides better laryngoscopic view and is advantageous in tracheal intubation in ankylosing spondylitis patients with difficult airway. Methods: This study was performed to investigate the use of the GlideScopeÒ for tracheal intubation in 15 patients wearing halo vests scheduled for elective surgery under general anesthesia. Preoperative airway assessments were evaluated to predict the difficulty of tracheal intubation. Before intubation, all patients were given a modified Cormack and Lehane (MCLS) grade and percentage of glottic opening (POGO) score by the intubating anesthesiologist having resorted to direct laryngoscopy (DL) with a Macintosh Size 3 blade depiction. Then intubation with the GlideScopeÒ was performed, during which the larynx was inspected and given another MCLS grade and POGO score. Results: Fourteen of the 15 patients had MCLS Grade III or IV by direct Macintosh laryngoscopy and were considered to have a difficult laryngoscopy. Nasal tracheal intubation by the GlideScopeÒ was successful on all occasions. The GlideScopeÒ improved the MCLS grade and POGO score in all patients who had put on a halo vest as compared with those on DL (p < 0.01). The GlideScopeÒ also provided a better laryngoscopic view than that by a DL. All of the patients who wore halo vests and presented with suspected difficult airways could be intubated successfully with the GlideScopeÒ. Conclusion: The use of the GlideScopeÒ for tracheal intubation could be an alternative option in patients with a difficult airway, whose surgery was circumscribed under general anesthesia with tracheal intubation. Copyright Ó 2011, Taiwan Society of Anesthesiologists. Published by Elsevier Taiwan LLC. All rights reserved.
Key words: intubation, intratracheal; laryngoscopy; laryngoscopes: GlideScopeÒ; orthotic devices: halo vest
1. Introduction The GlideScopeÒ (Verathon Medical B.V. Boerhaaveweg, Ijsselstein, The Netherlands) is a video laryngoscope developed for difficult airway management.1 The device consists of a light source and video camera located in the blade of a rigid plastic laryngoscope, which is connected to a separate liquid crystal display monitor. Previous studies have demonstrated that the GlideScopeÒ may provide a better laryngoscopic view than that by a direct laryngoscope2 (DL) and has a particular advantage over other devices for tracheal intubation in patients with difficult airway.3 Our previous investigation has demonstrated that the use of the GlideScopeÒ for tracheal intubation in patients with ankylosing spondylitis could be promising.4 Most of them presenting with difficult airways by DL could be successfully intubated nasally with the GlideScopeÒ for general anesthesia.
* Corresponding author. Department of Medical Education and Research, Mennonite Christian Hospital, No. 44, Min-chuan Road, Hualien, Taiwan, R.O.C. E-mail: [email protected] (H.-Y. Lai).
Because DL in patients who wear a halo vest is difficult for anesthesiologist to manipulate, successful intubation in such a circumstance is quite impossible. Moreover, the patients are frequently subject to failure of intubation with DL because of limited neck motility and mouth opening.5 Awake fiberoptic intubation is ideal in these patients because neck mobilization and wide mouth opening are unnecessary.6 However, this procedure will cause bodily suffering, and some patients may utterly refuse awake intubation. Furthermore, patients with cervical spine injuries often require urgent intubation under suboptimal conditions. The aim of the study was to investigate the use of GlideScopeÒ for tracheal intubation in patients who had worn a halo vest and preferred their surgery to be carried out under general anesthesia with intubation. 2. Methods After obtaining the approval of Hospital Ethics Committee and patient written informed consent, 15 consecutive patients who had to wear halo vests and were scheduled for elective surgery under general anesthesia with tracheal intubation in the period between
1875-4597/$ e see front matter Copyright Ó 2011, Taiwan Society of Anesthesiologists. Published by Elsevier Taiwan LLC. All rights reserved. doi:10.1016/j.aat.2011.08.005
Use of GlideScopeÒ for tracheal intubation
89 Table 2 Comparison of MCLS grades between DL and GS (n ¼ 15). DL
GS
I IIa IIb III IV All
Total
I
IIa
IIb
III
IV
0 0 3a 2a 0 5
0 0 0 7a 0 7
0 0 0 2a 1a 3
0 0 0 0 0 0
0 0 0 0 0 0
0 0 3 11 1 15
p < 0.01, compared with DL. The data were analyzed using the McNemar c2 test for matched pairs to examine GS-group MCLS grades. a Patients with improvement in MCLS grade. DL ¼ direct laryngoscopy; GS ¼ GlideScopeÒ intubation; MCLS ¼ modified Cormack and Lehane score.
Fig. 1. A Parker Flex-ItÔ articulating tracheal tube stylet was used for assisting nasotracheal intubation with the GlideScopeÒ.
December 2005 and November 2007 were recruited for the study. Preoperative airway assessments included Mallampati classification,7 thyromental distance, interincisor gap, and atlanto-occipital extension. The Mallampati score was recorded in the sitting position with mouth opened and tongue protruded. Thyromental distance was measured as the distance between the anterior chin and the thyroid notch. All examinations were performed by an anesthesiologist who was not involved in airway management. The tests for conditions of airway that foretold the likelihood of difficult intubation included the following: Mallampati classification 3; thyromental distance 6.5 cm; interincisor gap 4 cm; or atlantooccipital extension was limited. After the airway assessments, the anesthesiologist was requested to complete an airway assessment sheet and predict the ease of tracheal intubation as difficult or nondifficult. A standard anesthesia protocol was followed, and routine monitoring was applied. Patients were placed in the semisitting position having worn the halo vest. After preoxygenation through face mask with 100% oxygen for 5 minutes, inhalational induction of anesthesia with sevoflurane in oxygen was started without premedication. When the eyelash reflex disappeared, the end-tidal sevoflurane concentration was 4.5%. After ensuring that mask ventilation was smooth, 1.5 mg/kg succinylcholine was given intravenously. As full neuromuscular blockade was achieved, all
patients underwent an initial DL with Size 3 blade of Macintosh (Heine, Germany) laryngoscope, and the laryngeal views were scored in accordance with the modified Cormack and Lehane (MCLS) grading system8 and percentage of glottic opening (POGO).9 These were performed by an anesthesiologist who did not participate in preoperative airway assessment. After initial laryngoscopy, positive pressure ventilation was continued through a face mask, and then, the trachea was intubated with the GlideScopeÒ. Our previous experience revealed that the tracheal intubation with the GlideScopeÒ would be more smooth and easy through nasal but not oral passage.5 Nasotracheal intubations were performed by the sole anesthesiologist who had experience in anesthesia for more than 20 years and was seasoned in the use of the GlideScopeÒ (>1000 intubations). A Parker Flex-ItÔ (Parker Medical, USA) articulating tracheal tube stylet10 was used for assisting the intubation (Fig. 1). During intubation, the larynx was inspected and given a second MCLS grade and POGO score. A difficult tracheal intubation is defined as an MCLS Grade III or a POGO score of 0. Data were analyzed using the McNemar c2 test for matched pairs to examine MCLS grades between DL and GlideScopeÒ.3 A p value <0.05 was considered statistically significant. 3. Results Patients’ characteristics and the preoperative airway assessment data are shown in Table 1. The order of listing patients in Table 1 is sequential to the order of difficulties in tracheal intubation. After evaluation of preoperative airway by DL, all 15 patients were judged to have difficult airway, of whom 14 showed MCLS Grade III
Table 1 Patient characteristics and airway assessment by direct laryngoscopy and GlideScopeÒ. No.
Sex
Age (y)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
M M F M M M M F M M M M M M M
18 48 63 28 43 53 47 64 78 21 38 43 49 52 57
Preoperative evaluation MP II II II II II II III III III III III III III III IV
TMD
IG
þ þ
þ
þ þ þ þ þ
þ þ þ þ
DL
GS
Difficult intubation
AO
MCLS
POGO
MCLS
POGO
Pre.
DL
þ þ þ þ þ þ þ þ þ þ þ þ þ þ þ
IIb IIb IIb III III III III III III III III III III III IV
40 20 20 0 0 0 0 0 0 0 0 0 0 0 0
I I I I I IIa IIa IIa IIa IIa IIa IIa IIb IIb IIb
100 100 100 100 100 80 80 60 60 60 60 60 40 40 40
þ þ þ þ þ þ þ þ þ þ þ þ þ þ þ
þ þ þ þ þ þ þ þ þ þ þ þ þ þ
GS
AO ¼ atlanto-occipital limitation; DL ¼ direct laryngoscopy; F ¼ female; GS ¼ GlideScopeÒ intubation; IG ¼ interincisor gap <4 cm; M ¼ male; MCLS ¼ modified Cormack and Lehane score; MP ¼ Mallampatti classification; POGO ¼ percentage of glottis opening; Pre. ¼ predict difficulty intubation preoperative; TMD ¼ thyromental distance <6.5 cm.
90
or IV. Table 2 shows the comparison of MCLS grades between DL and GlideScopeÒ. All patients (100%) had improvement in the MCLS grade (p < 0.01) as seen with the GlideScopeÒ, and they could be nasally intubated successfully at the first attempt by GlideScopeÒ. 4. Discussion The present account is a report about a study chiefly for demonstrating the effectiveness of the GlideScopeÒ for management of difficult airway in patients wearing halo vests. Airway management and tracheal intubation in patients who had put on halo vests could be difficult and challenging. In design, the halo vest projects from the shoulders and holds the head in rigid fixation with four metallic struts and a metallic “halo” affixed to the skull with bolts. This cumbersome device, although restricts the movement of head and neck, prevents easy access by the anesthesiologist to the patient’s airway and rendering even mild neck extension, for aiding visualization of the larynx in conventional DL impossible.5 Awake fiberoptic tracheal intubation can be helpful to overcome the difficulties in general situation but not in pressing condition. Cricothyroidotomy is too invasive and may be enforced only in the emergent setting. Besides, Kitamura et al6 reported on fiberoptic intubation through laryngeal mask airway by using a tube exchange catheter under general anesthesia in Japanese patients wearing halo vests. Lu et al11 reported that the intubating laryngeal mask airway would be an alternative choice in patients with severe ankylosing spondylitis. However, nonanesthetic practitioners could be unfamiliar with the aforementioned equipments and techniques that need professional expertise. The GlideScopeÒ provides a better intubating condition in these patients, especially in emergent condition or when nasotracheal intubation is needed. In our previous study, we used the same predictor tests to evaluate the airway condition preoperatively in patients wearing halo vests and could predict the difficulties of tracheal intubation.4 We also found that the predictions were highly consistent with the MCLS grades disclosed by DL but not by GlideScopeÒ. This finding was similar to that of our study in ankylosing spondylitis patients, and it meant that the conventional airway assessment tests to predict difficulty of tracheal intubation cannot be substituted by GlideScopeÒ in most patients. After we first described successful nasotracheal intubation with the GlideScopeÒ, other reports12e14 also revealed that the main limitation in using the GlideScopeÒ was its inability of getting a good view of the glottis, but it could be helpful in manipulating the tracheal tube to pass the vocal cords, especially in patients wearing halo vests or those with restricted mouth opening. We have to emphasize again that nasal intubation could carry possibly significant morbidities, such as epistaxis and subsequent sinusitis. Thus, a thorough preparation before nasal intubation is imperative and should be taken into consideration while it is chosen. Comparing with the conventional DL, the GlideScopeÒ has the following characteristics: it provides better glottic view and does not need the three axes close in-line for tracheal intubation. However, the time for tracheal intubation with GlideScopeÒ is longer than that for DL in patients with normal airways, and manipulating it needs experience and skill.15,16 Furthermore, several articles have reported the clinical complications, such as tonsilar and palatal injuries, during the use of the GlideScopeÒ, and thus, its use is considerably limited.17e19 Videolaryngoscopy is rapidly becoming an established technique that can provide a good view of the larynx when conventional DL fails. It would change our conventional concepts of airway
S.-J. Huang et al.
management: that preoperative airway assessments could not predict the difficulties of tracheal intubation by videolaryngoscopes is denied; decision making in difficult-airway algorithm during recognized or anticipated difficult condition should also be modified, to wit-, patients with difficult airways must have the trachea intubated only with awake fiberoptic bronchoscopy may be too arbitrary. 5. Conclusion Our study showed that GlideScopeÒ for tracheal intubation for general anesthesia in patients wearing halo vests could provide a better view of the larynx than DL and facilitate successful nasotracheal intubation. It also demonstrated the growing information regarding the applicability of the GlideScopeÒ in patients with recognized difficult airways revealed by prior DL. Acknowledgments This study was supported by a research grant (TCDR-94A-38) from the Tzu Chi Charity Foundation. No person involved in this study has any financial relationship with the GlideScopeÒ or Saturn Biomedical Systems. References 1. Cooper RM. Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway. Can J Anaesth 2003;50:611e3. 2. Sun DA, Warriner CB, Parsons DG, Klein R, Umedaly HS, Moult M. The GlideScopeÒ video laryngoscope: randomized clinical trial in 200 patients. Br J Anaesth 2005;94:381e4. 3. Lim TJ, Lim Y, Liu EHC. Evaluation of ease of intubation with the GlideScopeÒ or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy. Anaesthesia 2005;60:180e3. 4. Lai HY, Chen IH, Chen A, Hwang FY, Lee Y. The use of the GlideScope for tracheal intubation in patients with ankylosing spondylitis. Br J Anaesth 2006;97:419e22. 5. Sims CA, Berger DL. Airway risk in hospitalized trauma patients with cervical injuries requiring halo fixation. Ann Surg. 2002;235:280e4. 6. Kitamura S, Yamada M, Morikawa M, Kamikawa K, Kono K. Fiberoptic intubation via laryngeal mask airway under general anesthesia in the patients with halo vest. Masui 2003;52:505e8. 7. Mallampatti SR, Gatt SP, Gugino LD. A clinical sign to predict difficult tracheal intubation: a prospective study. Can Anaesth Soc J 1985;32:429e34. 8. Yentis SM, Lee DJ. Evaluation of an improved scoring system for the grading of direct laryngoscopy. Anaesthesia 1998;53:1041e4. 9. Levitan RM, Ochroch EA, Rush S, Shofer FS, Hollander JE. Assessment of airway visualization: validation of the percentage of glottic opening (POGO) scale. Acad Emerg Med 1998;5:919e23. 10. Turkstra TP, Jones PM, Ower KM, Gros ML. The flex-it stylet is less effective than a malleable stylet for orotracheal intubation using the GlideScope. Anesth Analg 2009;109:1856e9. 11. Lu PP, Brimacombe J, Ho AC, Shyr MH, Liu HP. The intubating laryngeal mask airway in severe ankylosing spondylitis. Can J Anaesth 2001;48:1015e9. 12. Lai HY, Wang PK, Yang YL, Lai J, Chen TY. Facilitated insertion of a nasogastric tube in tracheal intubated patients using the GlideScope. Br J Anaesth 2006;97:749e50. 13. Xue F, Zhang G, Liu J, Li X, Sun H, Wang X, et al. A clinical assessment of the Glidescope videolaryngoscope in nasotracheal intubation with general anesthesia. J Clin Anesth 2006;18:611e5. 14. Hirabayashi Y. GlideScope videolaryngoscope facilitates nasotracheal intubation. Can J Anaesth 2006;53:1163e4. 15. Cooper RM, Pacey JA, Bishop MJ, McCluskey SA. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anaesth 2005;52:191e8. 16. Rai MR, Dering A, Verghese C. The GlideScope system: a clinical assessment of performance. Anaesthesia 2005;60:60e4. 17. Cross P, Cytryn J, Cheng KK. Perforation of the soft palate using the GlideScope videolaryngoscope. Can J Anaesth 2007;54:588e9. 18. Malik AM, Frogel JK. Anterior tonsillar pillar perforation during GlideScope video laryngoscopy. Anesth Analg 2007;104:1610e1. 19. Hsu WT, Hsu SC, Lee YL, Suang JS, Chen CL. Penetrating injury of the soft palate during GlideScope intubation. Anesth Analg 2007;104:1609e10.
Contents lists available at SciVerse ScienceDirect
Acta Anaesthesiologica Taiwanica journal homepage: www.e-aat.com
Original Article
The use of the GlideScopeÒ for tracheal intubation in patients with halo vest Shen-Jer Huang1, Chia-Lin Lee1, Po-Kai Wang1, Pei-Chin Lin1, Hsien-Yong Lai2 * 1 2
Department of Anesthesiology, Buddhist Tzu-Chi General Hospital, Hualien, Taiwan, R.O.C. Department of Medical Education and Research, Mennonite Christian Hospital, Hualien, Taiwan, R.O.C.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 July 2011 Received in revised form 9 August 2011 Accepted 12 August 2011
Objective: GlideScopeÒ provides better laryngoscopic view and is advantageous in tracheal intubation in ankylosing spondylitis patients with difficult airway. Methods: This study was performed to investigate the use of the GlideScopeÒ for tracheal intubation in 15 patients wearing halo vests scheduled for elective surgery under general anesthesia. Preoperative airway assessments were evaluated to predict the difficulty of tracheal intubation. Before intubation, all patients were given a modified Cormack and Lehane (MCLS) grade and percentage of glottic opening (POGO) score by the intubating anesthesiologist having resorted to direct laryngoscopy (DL) with a Macintosh Size 3 blade depiction. Then intubation with the GlideScopeÒ was performed, during which the larynx was inspected and given another MCLS grade and POGO score. Results: Fourteen of the 15 patients had MCLS Grade III or IV by direct Macintosh laryngoscopy and were considered to have a difficult laryngoscopy. Nasal tracheal intubation by the GlideScopeÒ was successful on all occasions. The GlideScopeÒ improved the MCLS grade and POGO score in all patients who had put on a halo vest as compared with those on DL (p < 0.01). The GlideScopeÒ also provided a better laryngoscopic view than that by a DL. All of the patients who wore halo vests and presented with suspected difficult airways could be intubated successfully with the GlideScopeÒ. Conclusion: The use of the GlideScopeÒ for tracheal intubation could be an alternative option in patients with a difficult airway, whose surgery was circumscribed under general anesthesia with tracheal intubation. Copyright Ó 2011, Taiwan Society of Anesthesiologists. Published by Elsevier Taiwan LLC. All rights reserved.
Key words: intubation, intratracheal; laryngoscopy; laryngoscopes: GlideScopeÒ; orthotic devices: halo vest
1. Introduction The GlideScopeÒ (Verathon Medical B.V. Boerhaaveweg, Ijsselstein, The Netherlands) is a video laryngoscope developed for difficult airway management.1 The device consists of a light source and video camera located in the blade of a rigid plastic laryngoscope, which is connected to a separate liquid crystal display monitor. Previous studies have demonstrated that the GlideScopeÒ may provide a better laryngoscopic view than that by a direct laryngoscope2 (DL) and has a particular advantage over other devices for tracheal intubation in patients with difficult airway.3 Our previous investigation has demonstrated that the use of the GlideScopeÒ for tracheal intubation in patients with ankylosing spondylitis could be promising.4 Most of them presenting with difficult airways by DL could be successfully intubated nasally with the GlideScopeÒ for general anesthesia.
* Corresponding author. Department of Medical Education and Research, Mennonite Christian Hospital, No. 44, Min-chuan Road, Hualien, Taiwan, R.O.C. E-mail: [email protected] (H.-Y. Lai).
Because DL in patients who wear a halo vest is difficult for anesthesiologist to manipulate, successful intubation in such a circumstance is quite impossible. Moreover, the patients are frequently subject to failure of intubation with DL because of limited neck motility and mouth opening.5 Awake fiberoptic intubation is ideal in these patients because neck mobilization and wide mouth opening are unnecessary.6 However, this procedure will cause bodily suffering, and some patients may utterly refuse awake intubation. Furthermore, patients with cervical spine injuries often require urgent intubation under suboptimal conditions. The aim of the study was to investigate the use of GlideScopeÒ for tracheal intubation in patients who had worn a halo vest and preferred their surgery to be carried out under general anesthesia with intubation. 2. Methods After obtaining the approval of Hospital Ethics Committee and patient written informed consent, 15 consecutive patients who had to wear halo vests and were scheduled for elective surgery under general anesthesia with tracheal intubation in the period between
1875-4597/$ e see front matter Copyright Ó 2011, Taiwan Society of Anesthesiologists. Published by Elsevier Taiwan LLC. All rights reserved. doi:10.1016/j.aat.2011.08.005
Use of GlideScopeÒ for tracheal intubation
89 Table 2 Comparison of MCLS grades between DL and GS (n ¼ 15). DL
GS
I IIa IIb III IV All
Total
I
IIa
IIb
III
IV
0 0 3a 2a 0 5
0 0 0 7a 0 7
0 0 0 2a 1a 3
0 0 0 0 0 0
0 0 0 0 0 0
0 0 3 11 1 15
p < 0.01, compared with DL. The data were analyzed using the McNemar c2 test for matched pairs to examine GS-group MCLS grades. a Patients with improvement in MCLS grade. DL ¼ direct laryngoscopy; GS ¼ GlideScopeÒ intubation; MCLS ¼ modified Cormack and Lehane score.
Fig. 1. A Parker Flex-ItÔ articulating tracheal tube stylet was used for assisting nasotracheal intubation with the GlideScopeÒ.
December 2005 and November 2007 were recruited for the study. Preoperative airway assessments included Mallampati classification,7 thyromental distance, interincisor gap, and atlanto-occipital extension. The Mallampati score was recorded in the sitting position with mouth opened and tongue protruded. Thyromental distance was measured as the distance between the anterior chin and the thyroid notch. All examinations were performed by an anesthesiologist who was not involved in airway management. The tests for conditions of airway that foretold the likelihood of difficult intubation included the following: Mallampati classification 3; thyromental distance 6.5 cm; interincisor gap 4 cm; or atlantooccipital extension was limited. After the airway assessments, the anesthesiologist was requested to complete an airway assessment sheet and predict the ease of tracheal intubation as difficult or nondifficult. A standard anesthesia protocol was followed, and routine monitoring was applied. Patients were placed in the semisitting position having worn the halo vest. After preoxygenation through face mask with 100% oxygen for 5 minutes, inhalational induction of anesthesia with sevoflurane in oxygen was started without premedication. When the eyelash reflex disappeared, the end-tidal sevoflurane concentration was 4.5%. After ensuring that mask ventilation was smooth, 1.5 mg/kg succinylcholine was given intravenously. As full neuromuscular blockade was achieved, all
patients underwent an initial DL with Size 3 blade of Macintosh (Heine, Germany) laryngoscope, and the laryngeal views were scored in accordance with the modified Cormack and Lehane (MCLS) grading system8 and percentage of glottic opening (POGO).9 These were performed by an anesthesiologist who did not participate in preoperative airway assessment. After initial laryngoscopy, positive pressure ventilation was continued through a face mask, and then, the trachea was intubated with the GlideScopeÒ. Our previous experience revealed that the tracheal intubation with the GlideScopeÒ would be more smooth and easy through nasal but not oral passage.5 Nasotracheal intubations were performed by the sole anesthesiologist who had experience in anesthesia for more than 20 years and was seasoned in the use of the GlideScopeÒ (>1000 intubations). A Parker Flex-ItÔ (Parker Medical, USA) articulating tracheal tube stylet10 was used for assisting the intubation (Fig. 1). During intubation, the larynx was inspected and given a second MCLS grade and POGO score. A difficult tracheal intubation is defined as an MCLS Grade III or a POGO score of 0. Data were analyzed using the McNemar c2 test for matched pairs to examine MCLS grades between DL and GlideScopeÒ.3 A p value <0.05 was considered statistically significant. 3. Results Patients’ characteristics and the preoperative airway assessment data are shown in Table 1. The order of listing patients in Table 1 is sequential to the order of difficulties in tracheal intubation. After evaluation of preoperative airway by DL, all 15 patients were judged to have difficult airway, of whom 14 showed MCLS Grade III
Table 1 Patient characteristics and airway assessment by direct laryngoscopy and GlideScopeÒ. No.
Sex
Age (y)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
M M F M M M M F M M M M M M M
18 48 63 28 43 53 47 64 78 21 38 43 49 52 57
Preoperative evaluation MP II II II II II II III III III III III III III III IV
TMD
IG
þ þ
þ
þ þ þ þ þ
þ þ þ þ
DL
GS
Difficult intubation
AO
MCLS
POGO
MCLS
POGO
Pre.
DL
þ þ þ þ þ þ þ þ þ þ þ þ þ þ þ
IIb IIb IIb III III III III III III III III III III III IV
40 20 20 0 0 0 0 0 0 0 0 0 0 0 0
I I I I I IIa IIa IIa IIa IIa IIa IIa IIb IIb IIb
100 100 100 100 100 80 80 60 60 60 60 60 40 40 40
þ þ þ þ þ þ þ þ þ þ þ þ þ þ þ
þ þ þ þ þ þ þ þ þ þ þ þ þ þ
GS
AO ¼ atlanto-occipital limitation; DL ¼ direct laryngoscopy; F ¼ female; GS ¼ GlideScopeÒ intubation; IG ¼ interincisor gap <4 cm; M ¼ male; MCLS ¼ modified Cormack and Lehane score; MP ¼ Mallampatti classification; POGO ¼ percentage of glottis opening; Pre. ¼ predict difficulty intubation preoperative; TMD ¼ thyromental distance <6.5 cm.
90
or IV. Table 2 shows the comparison of MCLS grades between DL and GlideScopeÒ. All patients (100%) had improvement in the MCLS grade (p < 0.01) as seen with the GlideScopeÒ, and they could be nasally intubated successfully at the first attempt by GlideScopeÒ. 4. Discussion The present account is a report about a study chiefly for demonstrating the effectiveness of the GlideScopeÒ for management of difficult airway in patients wearing halo vests. Airway management and tracheal intubation in patients who had put on halo vests could be difficult and challenging. In design, the halo vest projects from the shoulders and holds the head in rigid fixation with four metallic struts and a metallic “halo” affixed to the skull with bolts. This cumbersome device, although restricts the movement of head and neck, prevents easy access by the anesthesiologist to the patient’s airway and rendering even mild neck extension, for aiding visualization of the larynx in conventional DL impossible.5 Awake fiberoptic tracheal intubation can be helpful to overcome the difficulties in general situation but not in pressing condition. Cricothyroidotomy is too invasive and may be enforced only in the emergent setting. Besides, Kitamura et al6 reported on fiberoptic intubation through laryngeal mask airway by using a tube exchange catheter under general anesthesia in Japanese patients wearing halo vests. Lu et al11 reported that the intubating laryngeal mask airway would be an alternative choice in patients with severe ankylosing spondylitis. However, nonanesthetic practitioners could be unfamiliar with the aforementioned equipments and techniques that need professional expertise. The GlideScopeÒ provides a better intubating condition in these patients, especially in emergent condition or when nasotracheal intubation is needed. In our previous study, we used the same predictor tests to evaluate the airway condition preoperatively in patients wearing halo vests and could predict the difficulties of tracheal intubation.4 We also found that the predictions were highly consistent with the MCLS grades disclosed by DL but not by GlideScopeÒ. This finding was similar to that of our study in ankylosing spondylitis patients, and it meant that the conventional airway assessment tests to predict difficulty of tracheal intubation cannot be substituted by GlideScopeÒ in most patients. After we first described successful nasotracheal intubation with the GlideScopeÒ, other reports12e14 also revealed that the main limitation in using the GlideScopeÒ was its inability of getting a good view of the glottis, but it could be helpful in manipulating the tracheal tube to pass the vocal cords, especially in patients wearing halo vests or those with restricted mouth opening. We have to emphasize again that nasal intubation could carry possibly significant morbidities, such as epistaxis and subsequent sinusitis. Thus, a thorough preparation before nasal intubation is imperative and should be taken into consideration while it is chosen. Comparing with the conventional DL, the GlideScopeÒ has the following characteristics: it provides better glottic view and does not need the three axes close in-line for tracheal intubation. However, the time for tracheal intubation with GlideScopeÒ is longer than that for DL in patients with normal airways, and manipulating it needs experience and skill.15,16 Furthermore, several articles have reported the clinical complications, such as tonsilar and palatal injuries, during the use of the GlideScopeÒ, and thus, its use is considerably limited.17e19 Videolaryngoscopy is rapidly becoming an established technique that can provide a good view of the larynx when conventional DL fails. It would change our conventional concepts of airway
S.-J. Huang et al.
management: that preoperative airway assessments could not predict the difficulties of tracheal intubation by videolaryngoscopes is denied; decision making in difficult-airway algorithm during recognized or anticipated difficult condition should also be modified, to wit-, patients with difficult airways must have the trachea intubated only with awake fiberoptic bronchoscopy may be too arbitrary. 5. Conclusion Our study showed that GlideScopeÒ for tracheal intubation for general anesthesia in patients wearing halo vests could provide a better view of the larynx than DL and facilitate successful nasotracheal intubation. It also demonstrated the growing information regarding the applicability of the GlideScopeÒ in patients with recognized difficult airways revealed by prior DL. Acknowledgments This study was supported by a research grant (TCDR-94A-38) from the Tzu Chi Charity Foundation. No person involved in this study has any financial relationship with the GlideScopeÒ or Saturn Biomedical Systems. References 1. Cooper RM. Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway. Can J Anaesth 2003;50:611e3. 2. Sun DA, Warriner CB, Parsons DG, Klein R, Umedaly HS, Moult M. The GlideScopeÒ video laryngoscope: randomized clinical trial in 200 patients. Br J Anaesth 2005;94:381e4. 3. Lim TJ, Lim Y, Liu EHC. Evaluation of ease of intubation with the GlideScopeÒ or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy. Anaesthesia 2005;60:180e3. 4. Lai HY, Chen IH, Chen A, Hwang FY, Lee Y. The use of the GlideScope for tracheal intubation in patients with ankylosing spondylitis. Br J Anaesth 2006;97:419e22. 5. Sims CA, Berger DL. Airway risk in hospitalized trauma patients with cervical injuries requiring halo fixation. Ann Surg. 2002;235:280e4. 6. Kitamura S, Yamada M, Morikawa M, Kamikawa K, Kono K. Fiberoptic intubation via laryngeal mask airway under general anesthesia in the patients with halo vest. Masui 2003;52:505e8. 7. Mallampatti SR, Gatt SP, Gugino LD. A clinical sign to predict difficult tracheal intubation: a prospective study. Can Anaesth Soc J 1985;32:429e34. 8. Yentis SM, Lee DJ. Evaluation of an improved scoring system for the grading of direct laryngoscopy. Anaesthesia 1998;53:1041e4. 9. Levitan RM, Ochroch EA, Rush S, Shofer FS, Hollander JE. Assessment of airway visualization: validation of the percentage of glottic opening (POGO) scale. Acad Emerg Med 1998;5:919e23. 10. Turkstra TP, Jones PM, Ower KM, Gros ML. The flex-it stylet is less effective than a malleable stylet for orotracheal intubation using the GlideScope. Anesth Analg 2009;109:1856e9. 11. Lu PP, Brimacombe J, Ho AC, Shyr MH, Liu HP. The intubating laryngeal mask airway in severe ankylosing spondylitis. Can J Anaesth 2001;48:1015e9. 12. Lai HY, Wang PK, Yang YL, Lai J, Chen TY. Facilitated insertion of a nasogastric tube in tracheal intubated patients using the GlideScope. Br J Anaesth 2006;97:749e50. 13. Xue F, Zhang G, Liu J, Li X, Sun H, Wang X, et al. A clinical assessment of the Glidescope videolaryngoscope in nasotracheal intubation with general anesthesia. J Clin Anesth 2006;18:611e5. 14. Hirabayashi Y. GlideScope videolaryngoscope facilitates nasotracheal intubation. Can J Anaesth 2006;53:1163e4. 15. Cooper RM, Pacey JA, Bishop MJ, McCluskey SA. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anaesth 2005;52:191e8. 16. Rai MR, Dering A, Verghese C. The GlideScope system: a clinical assessment of performance. Anaesthesia 2005;60:60e4. 17. Cross P, Cytryn J, Cheng KK. Perforation of the soft palate using the GlideScope videolaryngoscope. Can J Anaesth 2007;54:588e9. 18. Malik AM, Frogel JK. Anterior tonsillar pillar perforation during GlideScope video laryngoscopy. Anesth Analg 2007;104:1610e1. 19. Hsu WT, Hsu SC, Lee YL, Suang JS, Chen CL. Penetrating injury of the soft palate during GlideScope intubation. Anesth Analg 2007;104:1609e10.