| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
From the Department of Anaesthesia, Chang Gung Memorial Hospital, 5 Fu-hsing Street, Kwei-shan, Taoyuan 333, Taiwan, Republic of China.
Address correspondence to: Ming-Hwang Shyr MD PhD, Phone: 886-3-3281200, Ext. 2324; Fax: 886-3-3342068; E-mail: an001{at}adm.cgmh.com.tw
 |
Abstract |
|---|
 TOP Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Methods: After informed consent, 240 ASA I-II adults undergoing elective surgery participated in a randomized, single blind clinical trial to receive blind trachea intubation via ILMA with a conventional tracheal tube curved with normal (Normal group) or reversed (Reverse group) direction. More than three attempts at intubation was regarded as failure. The lowest oxygen saturation during intubation was recorded and postintubation sore throat and hoarseness were evaluated with verbal analog scales.
Results: The overall success rates of intubation with Normal and Reverse groups were not different (96.7% and 94.2% respectively). Successful intubation at the first attempt was higher in the Reverse group than in the Normal group (86.7% vs 75.0%, P=0.033). The incidence of sore throat was higher in the Normal group than in the Reverse group (19.2% vs 9.2% respectively, P =0.042).
Conclusions: Blind trachea intubation via an ILMA with the conventional curved tracheal tube is feasible and highly successful. Reverse curve direction is preferable at the first attempt of intubation for its higher success rate and lower incidence of complications.
|
Introduction |
|---|
|
TOPAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Reported success rates of blind tracheal intubation via the ILMA have varied between 89.51–100%.8–11 The preliminary study reported by Brain et al.11 utilized a straight, reusable silicone tracheal tube (Accusil Inc, IN, USA). Successful tracheal intubation via the ILMA using a conventional polyvinyl chloride tracheal tube has been reported by many authors.4,8–10 Joo & Rose 12 advocate tracheal intubation via ILMA with the tracheal tube inserted in a reversed curve, instead of the conventional normal curve, but there has been no controlled comparative study.
We embarked on a prospective study to investigate the success rate of blind tracheal intubation via an ILMA with different curve directions of a conventional tracheal tube, and to examine the associated complications.
|
Methods |
|---|
|
TOPAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Anesthetic management was standardized. Monitoring was applied pre-induction and included an electrocardiograph, pulse oximeter, capnograph and noninvasive blood pressure monitor. The head and neck of patients were placed in a neutral position. Patients were pre-oxygenated and anesthesia was induced with 4–6 mg·kg–1 thiopental, 3–5 µg·kg–1 fentanyl and muscular relaxation was facilitated with 0.5 mg·kg–1 atracurium iv. The ILMA (LMA-FastrachTM, The Laryngeal Mask Company Ltd, United Kingdom) was inserted when the jaw was relaxed, the eyelash reflex absent and the patient apneic. The size #4 ILMA was the initial choice for men weighing > 75 kg and the size #3 was selected for all women and men < 75 kg. After insertion, using a hand-held cuff inflator-manometer, the ILMA was inflated to an intracuff pressure of 60–70 cm H2O. Optimal ILMA position was judged by chest wall movement and CO2 exchange on capnograph during gentle manually assisted ventilation. The operator was allowed to change to another size of ILMA or make necessary ILMA adjustments (pull-up or push-down, rightward or leftward rotation) if ventilation was not satisfactory. Following lubrication with a bolus of water-soluble jelly (K-Y lubricating jelly, Johnson & Johnson), a conventional tracheal tube (Sheridan® tracheal tube, The Kendall Company, USA) was inserted with the selected curvature and passed into the trachea via the ILMA. A tracheal tube of 7.0 mm I.D. was selected for women and 7.5 mm I.D. tracheal tube for men. During the attempt of intubation, patient was kept anesthetized with volatile anesthetics in 100% O2. Successful tracheal intubation was confirmed by CO2 exchange on capnograph. Following successful tracheal intubation, the ILMA was removed and the tracheal tube was left in situ.
All ILMA placements and tracheal intubations were performed by the same staff anesthesiologist who had placed the ILMA on fewer than 10 occasions before the study commenced. Patients were randomly assigned into two groups: Normal and Reverse groups. In each patient intubation via the ILMA was limited to three attempts. Intubation proceeded with the tracheal tube inserted in the same selected curvature (normal curve in Normal group and reversed curve in Reverse group) for the first two attempts. The third attempt at intubation, when required, used the opposite curve. Following each failed intubation, the position of the ILMA was adjusted if necessary.
The lowest oxygen saturation during the procedure was recorded. Post-intubation sore throat and hoarseness were evaluated by verbal analog scales (VAS) on visit the next day. A VAS > 3 was considered clinically significant.
The success rates of blind tracheal intubation via ILMA in Normal and Reverse groups were compared using the chi-square test with Yates correction. Inter-group and intra-group comparisons were analyzed. The incidences of sore throat and hoarseness were also analyzed with chi-square test with Yates correction. A P < 0.05 was considered statistically significant.
|
Results |
|---|
|
TOPAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
. Mean age and weight were 44 ± 17 (range 18–84) yr and 62 ± 11 (35–95) kg respectively. The male:female ratio was 152:88.
|
The success rates of blind tracheal intubation via ILMA in both groups are illustrated in Table II. Tracheal intubation was successful in 229 of 240 (95.4%) patients. The average number of intubation attempts was 1.37. There was no difference in the success rates of blind tracheal intubation between the Normal and Reverse groups (96.7% and 94.2% respectively, P=0.537). The first attempt success rate in Reverse group was higher than that in Normal group (86.7% and 75.0% respectively, P=0.033). The success rates of blind tracheal intubation at second and third attempt did not differ between two groups.
|
The incidence of sore throat was 14.2% and was higher in the Normal than in the Reverse group (P=0.042, Table III). The sore throat was mostly mild in degree, self-limited and needed no medical interventions. The average number of intubation attempts was higher in those with sore throat VAS > 3 (1.85 vs 1.03). The incidence of hoarseness did not differ between two groups (P=0.497).
|
|
Discussion |
|---|
|
TOPAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Many authors have postulated that the steep curvature of the tracheal tube, when inserted in its normal curvature, might have a lower intubation success rate. In our study, the success rates of blind tracheal intubation did not differ between Normal and Reverse groups (96.7% and 94.2% respectively). Kapila et al.8 and Joo & Rose12 also reported tracheal intubation via ILMA with the tracheal tube inserted in normal and reverse direction respectively. Their overall success rates ranged from 93.0% to 96.7% and first attempt success rates varied between 72.0% and 86.7%. In our study, the first attempt success rate was higher in the Reverse than in the Normal group (86.7% vs 75.0% respectively). In contrast to their multiauthored studies with small case numbers, our study of 240 patients was operated by a single anesthesiologist. We tried to manipulate the ILMA before each attempt at intubation whereas Kapila et al. performed ILMA manipulations (pulling back or pushing down) only if the first intubation attempt failed. Manipulating the ILMA is important, because it improves alignment of the mask with the larynx.8 Good ventilation via the ILMA indicates good mask-larynx relationship. The efficacy of pulmonary ventilation could be recognized subjectively through manual ventilation and, objectively, through the CO2 exchange on the capnograph and the airway pressure read on monitor. In our study, 54.5% of the failure was attributed to the inability in obtaining the optimal ILMA position despite efforts in ILMA manipulation.
The incidences of sore throat and hoarseness following standard LMA use are approximately 28.8% and 11%.13 In our study, the incidences of sore throat and hoarseness were 14.2% and 3.75% respectively. Sore throat was associated with an increased number of intubation attempts (1.85 vs 1.03) and tracheal tube curvature. The steep curvature of tracheal tube when it exits the ILMA might be responsible for the higher sore throat score. Though highly successful and without clinical complications, operators should be aware of the potential complications associated with blind intubation via the ILMA.14 Caution must be used with passage of PVC tube into the ILMA and the use of force must be avoided to prevent airway trauma.
Blind tracheal intubation via an ILMA has many potential advantages. First, it is not necessary to visualize the larynx during intubation and, consequently, there is negligible cervical spine movement.15 Second, ILMA placement needs mouth opening gap of 2 cm. In patients with temporo-mandibular joint disturbance and bad dentition, the trachea could be intubated via the ILMA. Furthermore, placement of the ILMA is independent of factors used to predict difficult intubation.16 In addition, the ILMA allows continuous oxygenation during attempts of intubation and hence, less likelihood of desaturation. The ILMA has been reported to solve many problems associated with the difficult airway.2,4–7 Personnel should gain experience and become familiar with this new device. It could prove invaluable to emergency room physicians when head and neck manipulation is contraindicated or prohibited 17 and to anesthesiologists in situations where back-up help is not always available. Nevertheless, the addition of cricoid pressure has been shown to impair the ability to intubate through the ILMA.18
In conclusion, we recommend the use of the conventional tracheal tube, instead of the autoclavable and reusable ILMA tracheal tube, for tracheal intubation via the ILMA because they are effective, less expensive, disposable, readily available and associated with no clinical complications. To achieve higher success rate of intubation, we advocate the use of the reverse curve at the first attempt and, if it fails, switch to the opposite direction at the second attempt.
Accepted for publication March 19, 2000.
|
References |
|---|
|
TOPAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
2 Brain AIJ. Three cases of difficult intubation overcome by the laryngeal mask airway. Anaesthesia 1985; 40: 353–5.[Medline]
3
Parmet JL, Colonna-Romano P, Horrow JC, Miller F, Gonzales J, Rosenberg H. The laryngeal mask airway reliably provides rescue ventilation in case of unanticipated difficult tracheal intubation along with difficult mask ventilation. Anesth Analg 1998; 87: 661–5.
4 Joo H, Rose K. Fastrach – a new intubating laryngeal mask airway: successful use in patients with difficult airways. Can J Anaesth 1998; 45: 253–6.[Abstract]
5 Shung J, Avidan MS, Ing R, Klein DC, Pott L. Awake intubation of the difficult airway with the intubating laryngeal mask airway. Anaesthesia 1998; 53: 645–9.[Medline]
6 Parr MJA, Gregory M, Baskett PJF. The intubating laryngeal mask. Use in failed and difficult intubation. Anaesthesia 1998; 53: 343–8.[Medline]
7 Fukutome T. Amaha K. Nakazawa K. Kawamura T. Noguchi H. Tracheal intubation through the intubating laryngeal mask airway (LMA-FastrachTM) in patients with difficult airways. Anaesth Intensive Care 1998; 26: 387–91.[Medline]
8
Kapila A, Addy EV, Verghese C, Brain AIJ. The intubating laryngeal mask airway: an initial assessment of performance. Br J Anaesth 1997; 79: 710–3.
9 Cros AM, Colombani S. Preliminary study of intubation with a new laryngeal mask for difficult intubation. Anesthesiology 1997; 87: A482.
10 Ferson DZ, Supkis DE, Rahlfs TF, Jones RL. Evaluation of the intubating laryngeal mask as a primary airway device and a guide for blind endotracheal intubation. Anesthesiology 1997; 87: A485.
11
Brain AIJ, Verghese C, Addy EV, Kapila A, Brimacombe J. The intubating laryngeal mask. II: a preliminary clinical report of a new means of intubating the trachea. Br J Anaesth 1997; 79: 704–9.
12
Joo HS, Rose DK. The intubating laryngeal mask airway with and without fiberoptic guidance. Anesth Analg 1999; 88: 662–6.
13
Figueredo E, Vivar-Diago M, Muñoz-Blanco F. Laryngo-pharyngeal complaints after use of the laryngeal mask airway. Can J Anesth 1999; 46: 220–5.
14 Branthwaite MA. An unexpected complication of the intubating laryngeal mask. Anaesthesia 1999; 54: 166–7.[Medline]
15
Nakazawa K, Tanaka N, Ishikawa S et al. Using the intubating laryngeal mask airway (LMA-FastrachTM) for blind endotracheal intubation in patients undergoing cervical spine operation. Anesth Analg 1999; 89: 1319–21.
16 Brimacombe J. Analysis of 1500 laryngeal mask uses by one anaesthetist in adults undergoing routine anaesthesia. Anaesthesia 1996; 51: 76–80.[Medline]
17 Schuschnig C, Waltl B, Erlacher W, Reddy B, Stoik W, Kapral S. Intubating laryngeal mask and rapid sequence induction in patients with cervical spine injury. Anaesthesia 1999; 54: 787–97.[Medline]
18 Harry RM, Nolan JP. The use of cricoid pressure with the intubating laryngeal mask. Anaesthesia 1999; 54: 656–9.[Medline]
This article has been cited by other articles:
 |
|
 |
|
  A. Nileshwar and A. Thudamaladinne Comparison of intubating laryngeal mask airway and Bullard laryngoscope for oro-tracheal intubation in adult patients with simulated limitation of cervical movements Br. J. Anaesth., August 1, 2007; 99(2): 292 - 296. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Kundra, N. Sujata, and M. Ravishankar Conventional Tracheal Tubes for Intubation Through the Intubating Laryngeal Mask Airway Anesth. Analg., January 1, 2005; 100(1): 284 - 288. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. S. Joo, M. T. Kataoka, R. J.B. Chen, J. Doyle, and C. D. Mazer PVC tracheal tubes exert forces and pressures seven to ten times higher than silicone or armoured tracheal tubes - an in vitro study: [Les tubes tracheaux de PVC exercent des forces et des pressions de sept a dix fois plus elevees que les tubes en silicone ou les tubes armes - une etude in vitro] Can J Anesth, November 1, 2002; 49(9): 986 - 989. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P.-P. Lu, J. Brimacombe, A. C. Y. Ho, M.-H. Shyr, and H.-P. Liu The intubating laryngeal mask airway in severe ankylosing spondylitis : [L'utilisation du masque larynge d'intubation en cas de spondylarthrite ankylosante severe] Can J Anesth, November 1, 2001; 48(10): 1015 - 1019. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Okuda, G. Inagawa, T. Miwa, and K. Hiroki Influence of head and neck position on cuff position and oropharyngeal sealing pressure with the laryngeal mask airway in children Br. J. Anaesth., January 1, 2001; 86(1): 122 - 124. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. J. Shysh Adult learning principles: you can teach an old dog new tricks/On peut apprendre a tout age Can J Anesth, September 1, 2000; 47(9): 837 - 842. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
