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TRANSILLUMINATED TRACHEAL INTUBATION
Br. J. Anaesth. (1989), 62, 494-497
TRANSILLUMINATED TRACHEAL INTUBATION Q. P. AINSWORTH AND T. H. HOWELLS
SUMMARY We evaluated the use of an inexpensive transilluminating light wand for tracheal intubation. Expertise in its use was acquired quickly, thereby providing successful per-oral intubation in all patients who were able to open the mouth, irrespective of the view obtained of the epiglottis and larynx.
be seen; grade 4 = not even the epiglottis can be seen. The purpose of this study was to determine the relationship between the grade of laryngeal view and the subsequent ease of tracheal intubation by transillumination. METHODS
After a period of familiarization, the manufacturer's instructions for use were abandoned in favour of the following technique. A lubricated Portex Blue-Line tracheal tube was cut to the appropriate length, the light wand inserted into the tube and shaped to a slightly exaggerated pharyngo-laryngeal curve. With the operator standing at the head of the patient (as for laryngoscopic intubation) the thumb of the operator's gloved left hand was placed in the floor of the mouth behind the symphysis menti and the lower jaw was gently lifted anteriorly to move the tongue and epiglottis away from the posterior pharyngeal wall. The room was darkened while the illuminated apparatus was introduced by the right hand into the right side of the mouth, directing the tip towards the left. In all cases a brilliant transillumination was observed in the skin of the left side of the neck when the tip impacted within or adjacent to the left piriform fossa (left-handed Q. P. AlNSWORTH, M.B., CH.B; T . HILARY HOWELLS, operators could perform the mirror image manipuF.F.A.R.C.S., D.A.; Department of Anaesthesia, The Royal Free Hospital, Pond Street, Hampstead, London NW3 2QG. lations, but are probably more familiar with righthanded intubation, as in direct laryngoscopy). Accepted for Publication: November 15, 1988.
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015
Occasional difficulty in tracheal intubation is a feature of clinical anaesthesia. Guided intubation using transillumination of neck tissue was described first by Yamamura, Yamamoto and Kamiyama in 1959 [1]. The first study of its use was published by Ducrow [2] in 1978 and commented upon by Ray burn [3]. Further accounts have followed [4-13]. In earlier studies, the transilluminator used was the Flexilum surgical light, but its bulb had a tendency to become detached [4,7,8] and so the instrument was modified for specific use in the trachea and it was named the Tube-Stat. This is a semi-flexible illumination wand with a battery handle. It is suited ideally for the double function of a tube strengthening stylet and a source of transillumination. The flexible shaft is 25 cm in length and therefore protrudes when placed within a cut tracheal tube. We devised a tubular spacer to add effective length to the cut tracheal tube and, by friction, to grip the stylet handle, thereby making the assembly rigid during handling. The bulb is advanced to within 1 cm of the tip of the tube by longitudinal movement of the stylet within the tracheal tube and spacer (fig. 1). The instructions supplied for use with the wand are complex. In practice, the manipulations suggested by the manufacturer have not proved necessary, and we believe a simplified practice such as that described below would help to encourage the use of this device. A method for grading difficulty in intubation based on laryngoscopic view has been suggested by Cormack and Lehane [14]: grade 1 = most of the glottis is visible; grade 2 = only the posterior extremity of the glottis is visible; grade 3 = only the epiglottis is visible, no part of the glottis can
TRACHEAL INTUBATION
Observation of the intensity of the transillumination at this site indicated approximately how far into the mouth the apparatus should be inserted in order to reach the laryngeal inlet and so mitigated against any tendency of the operator to insert the tracheal tube into the oesophagus. It indicated also the light intensity that was expected subsequently when the Tube-Stat was transilluminating through the larynx and trachea. For instance, thick-necked, pigmented individuals yielded weaker transillumination than the thin, fair-skinned patient. Subsequently, the tip of the apparatus was withdrawn slightly and then advanced in the midline, first towards the posterior pharyngeal wall and then anteriorly to reach the glottis. The final approach and entry into the larynx produced intense transillumination, always greater than that previously identified in the neck. The shadows of the laryngeal cartilages were often apparent at this stage. Further advancement demonstrated a bright ball of light descending down the midline and slightly towards the left. If oesophageal passage occurred, while a transillumination was often apparent, it was more diffuse and its intensity was markedly less than that observed first in the neck. After initial familiarization and practice with the Tube-Stat, we studied 200 patients requiring
tracheal intubation for their anaesthetic management. They were prepared for intubation under general anaesthesia with an intubating dose of a neuromuscular blocker and ventilation of the lungs with oxygen. Each patient was given a laryngeal view grade and received 4 % lignocaine 3-4 ml by spray during laryngoscopy. Following this preparation, all intubations were executed by one of us (THH) and allocated a success score: I = success at first attempt; II = success after three attempts; III = success after multiple attempts within 1 min; IV = failure to intubate after 1 min. The laryngeal view grade and success scores were allocated by the intubator. Successful intubation was confirmed by chest movements and auscultation. RESULTS
Laryngoscopic view grades and success scores are shown in table I. The frequency of grade 2 and 3 laryngeal views in our study was greater than that observed by Cormack and Lehane, possibly because of a rather large percentage of elderly mid-European patients with elaborate dental conservation in our local population. Every trachea was intubated successfully within
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015
FIG. 1. The Tube-Stat illumination wand (top), tracheal tube plus spacer (middle), and assembled unit (bottom).
BRITISH JOURNAL OF ANAESTHESIA
496 TABLE I. Number of patients allocated to each success score and each laryngoscopic view grade
Success score View grade 1 2 3 4
II
III
IV
Total
154 12 8 1 175
22 0 1 0 23
2 0 0 0 2 1
0 0 0 0 0 0
178 12 9 1
87.5
11.5
89 6 4.5 0.5
200 100
1 min from the introduction of the intubating apparatus and most intubations were accomplished with ease at the first attempt. Only in one subject was difficulty experienced in relation to a "difficult" grading. In the remainder, there was no apparent correlation between "difficult" grading and intubation success scores.
DISCUSSION
Other studies have indicated that the speed and success of tracheal intubation by transillumination varies with the experience of the intubator [7,9], but that the technique is learned easily with a minimum of practice [3,10]. In the present study, all intubations were performed by one operator, and therefore the results may be biased towards the expert. We believe that the grade 3 laryngeal view, which is not uncommon, causes the average anaesthetist great difficulty at intubation. In this situation, many anaesthetists would use a styletted Oxford tube, but transillumination is an alternative which has been shown to have high success rates. Grade 4 laryngeal views are rare in the general surgical population and patients in this category present great difficulty for intubation. In these subjects the styletted Oxford tube method is rarely effective and transillumination may be valuable. It has been suggested that transillumination may be a suitable method for tracheal intubation under "field" conditions [7,8]. Our experience suggests that satisfactory conditions are met only when a darkened environment can be obtained and that transillumination in daylight may not be a reliable indicator of successful intubation (although absolute darkness is not mandatory).
REFERENCES 1. Yamamura H, Yamamoto T, Kamiyama M. Device for blind nasal intubation. Anesthcsialogy 1959; 20: 221. 2. Ducrow M. Throwing light on blind intubation. Anaesthesia 1978; 33: 827-829. 3. Rayburn RL. "Light wand" intubation. Anaesthesia 1979; 34: 677-678. 4. Stone DJ, Stirt JA, Kaplan MJ, McLean W'C. A complication of lightwand-guided nasotracheal intubation. Anesthesiology 1984; 61: 780-781. 5. Weis FR jr, Kaiser RE. Lightwand-guided nasotracheal intubation is an effective technique. Anesthesiologv 1985; 62: 839-840. 6. Hammer M, Garry B. Transillumination of the trachea with Flexilum. Anesthesia and Analgesia 1985; 64: 91-92. 7. Vollmer TP, Stewart RD, Paris PM, Ellis DG, Berkebile PE. Use of a lighted stylet for guided orotracheal intubation in the prehospital setting. Annals of Emergency Medicine 1985; 14: 324-328. 8. Williams RT, Stewart RD. Transillumination of the trachea with a lighted stylet. Anesthesia and Analgesia 1986; 65: 542-543. 9. Ellis DG, Jakymec A, Kaplan RM, Stewart RD, Freeman JA, Bleyaert A, Berkebile PE. Guided orotracheal intubation in the operating room using a lighted stylet: a comparison with direct laryngoscopic technique. Anesthesiology 1986; 64: 823-826. 10. Fox DJ, Castro T jr, Rastrelli AJ. Comparison of intubation techniques in the awake patient: the FlexiLum surgical light (Lightwand) versus blind nasal approach. Anesthesiology 1987; 66: 69-71.
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015
Total
I
While others [7,8] have experience in Lightwand-guided intubation in emergency cases, we cannot make recommendations on its use in situations where the risk or regurgitation is high. The prevailing lighting conditions and the absence of direct laryngoscopic view preclude early recognition of regurgitation, and cricoid pressure may affect the ease of intubation. Other studies have shown that there is no increased incidence of major or minor complications with this technique compared with laryngoscopic intubation [7,9]. We re-used the same Tube-Stat for familiarization, throughout the study and subsequently for a total of 250 intubations. After each use, the stylet portion was sterilized with chlorhexidine in spirit 0.5",, w/v. There was a reduction in light intensity of our first device which was noticeable only when compared with a new unit. Note: The Tube-Stat is manufactured by Concept Incorporated (U.S.A.) and distributed by Henleys Medical Supplies Ltd (London). The unit costs £25.20 and it is designated as a "limited re-use instrument".
TRACHEAL INTUBATION 11. Stewart RD, Ellis DG. Lighted stylet and endotracheal intubation. I. Anesthesiology 1987; 66: 851. 12. Williams RT. Lighted stylet and endotracheal intubation. II. Anesthesiology 1987; 66: 851-852.
497 13. Mehta S. Guided orotracheal intubation in the operating room using a lighted stylet. Anesthesiology 1987; 66: 105. 14. Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39: 1105-1111.
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015
TRANSILLUMINATED TRACHEAL INTUBATION Q. P. AINSWORTH AND T. H. HOWELLS
SUMMARY We evaluated the use of an inexpensive transilluminating light wand for tracheal intubation. Expertise in its use was acquired quickly, thereby providing successful per-oral intubation in all patients who were able to open the mouth, irrespective of the view obtained of the epiglottis and larynx.
be seen; grade 4 = not even the epiglottis can be seen. The purpose of this study was to determine the relationship between the grade of laryngeal view and the subsequent ease of tracheal intubation by transillumination. METHODS
After a period of familiarization, the manufacturer's instructions for use were abandoned in favour of the following technique. A lubricated Portex Blue-Line tracheal tube was cut to the appropriate length, the light wand inserted into the tube and shaped to a slightly exaggerated pharyngo-laryngeal curve. With the operator standing at the head of the patient (as for laryngoscopic intubation) the thumb of the operator's gloved left hand was placed in the floor of the mouth behind the symphysis menti and the lower jaw was gently lifted anteriorly to move the tongue and epiglottis away from the posterior pharyngeal wall. The room was darkened while the illuminated apparatus was introduced by the right hand into the right side of the mouth, directing the tip towards the left. In all cases a brilliant transillumination was observed in the skin of the left side of the neck when the tip impacted within or adjacent to the left piriform fossa (left-handed Q. P. AlNSWORTH, M.B., CH.B; T . HILARY HOWELLS, operators could perform the mirror image manipuF.F.A.R.C.S., D.A.; Department of Anaesthesia, The Royal Free Hospital, Pond Street, Hampstead, London NW3 2QG. lations, but are probably more familiar with righthanded intubation, as in direct laryngoscopy). Accepted for Publication: November 15, 1988.
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015
Occasional difficulty in tracheal intubation is a feature of clinical anaesthesia. Guided intubation using transillumination of neck tissue was described first by Yamamura, Yamamoto and Kamiyama in 1959 [1]. The first study of its use was published by Ducrow [2] in 1978 and commented upon by Ray burn [3]. Further accounts have followed [4-13]. In earlier studies, the transilluminator used was the Flexilum surgical light, but its bulb had a tendency to become detached [4,7,8] and so the instrument was modified for specific use in the trachea and it was named the Tube-Stat. This is a semi-flexible illumination wand with a battery handle. It is suited ideally for the double function of a tube strengthening stylet and a source of transillumination. The flexible shaft is 25 cm in length and therefore protrudes when placed within a cut tracheal tube. We devised a tubular spacer to add effective length to the cut tracheal tube and, by friction, to grip the stylet handle, thereby making the assembly rigid during handling. The bulb is advanced to within 1 cm of the tip of the tube by longitudinal movement of the stylet within the tracheal tube and spacer (fig. 1). The instructions supplied for use with the wand are complex. In practice, the manipulations suggested by the manufacturer have not proved necessary, and we believe a simplified practice such as that described below would help to encourage the use of this device. A method for grading difficulty in intubation based on laryngoscopic view has been suggested by Cormack and Lehane [14]: grade 1 = most of the glottis is visible; grade 2 = only the posterior extremity of the glottis is visible; grade 3 = only the epiglottis is visible, no part of the glottis can
TRACHEAL INTUBATION
Observation of the intensity of the transillumination at this site indicated approximately how far into the mouth the apparatus should be inserted in order to reach the laryngeal inlet and so mitigated against any tendency of the operator to insert the tracheal tube into the oesophagus. It indicated also the light intensity that was expected subsequently when the Tube-Stat was transilluminating through the larynx and trachea. For instance, thick-necked, pigmented individuals yielded weaker transillumination than the thin, fair-skinned patient. Subsequently, the tip of the apparatus was withdrawn slightly and then advanced in the midline, first towards the posterior pharyngeal wall and then anteriorly to reach the glottis. The final approach and entry into the larynx produced intense transillumination, always greater than that previously identified in the neck. The shadows of the laryngeal cartilages were often apparent at this stage. Further advancement demonstrated a bright ball of light descending down the midline and slightly towards the left. If oesophageal passage occurred, while a transillumination was often apparent, it was more diffuse and its intensity was markedly less than that observed first in the neck. After initial familiarization and practice with the Tube-Stat, we studied 200 patients requiring
tracheal intubation for their anaesthetic management. They were prepared for intubation under general anaesthesia with an intubating dose of a neuromuscular blocker and ventilation of the lungs with oxygen. Each patient was given a laryngeal view grade and received 4 % lignocaine 3-4 ml by spray during laryngoscopy. Following this preparation, all intubations were executed by one of us (THH) and allocated a success score: I = success at first attempt; II = success after three attempts; III = success after multiple attempts within 1 min; IV = failure to intubate after 1 min. The laryngeal view grade and success scores were allocated by the intubator. Successful intubation was confirmed by chest movements and auscultation. RESULTS
Laryngoscopic view grades and success scores are shown in table I. The frequency of grade 2 and 3 laryngeal views in our study was greater than that observed by Cormack and Lehane, possibly because of a rather large percentage of elderly mid-European patients with elaborate dental conservation in our local population. Every trachea was intubated successfully within
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015
FIG. 1. The Tube-Stat illumination wand (top), tracheal tube plus spacer (middle), and assembled unit (bottom).
BRITISH JOURNAL OF ANAESTHESIA
496 TABLE I. Number of patients allocated to each success score and each laryngoscopic view grade
Success score View grade 1 2 3 4
II
III
IV
Total
154 12 8 1 175
22 0 1 0 23
2 0 0 0 2 1
0 0 0 0 0 0
178 12 9 1
87.5
11.5
89 6 4.5 0.5
200 100
1 min from the introduction of the intubating apparatus and most intubations were accomplished with ease at the first attempt. Only in one subject was difficulty experienced in relation to a "difficult" grading. In the remainder, there was no apparent correlation between "difficult" grading and intubation success scores.
DISCUSSION
Other studies have indicated that the speed and success of tracheal intubation by transillumination varies with the experience of the intubator [7,9], but that the technique is learned easily with a minimum of practice [3,10]. In the present study, all intubations were performed by one operator, and therefore the results may be biased towards the expert. We believe that the grade 3 laryngeal view, which is not uncommon, causes the average anaesthetist great difficulty at intubation. In this situation, many anaesthetists would use a styletted Oxford tube, but transillumination is an alternative which has been shown to have high success rates. Grade 4 laryngeal views are rare in the general surgical population and patients in this category present great difficulty for intubation. In these subjects the styletted Oxford tube method is rarely effective and transillumination may be valuable. It has been suggested that transillumination may be a suitable method for tracheal intubation under "field" conditions [7,8]. Our experience suggests that satisfactory conditions are met only when a darkened environment can be obtained and that transillumination in daylight may not be a reliable indicator of successful intubation (although absolute darkness is not mandatory).
REFERENCES 1. Yamamura H, Yamamoto T, Kamiyama M. Device for blind nasal intubation. Anesthcsialogy 1959; 20: 221. 2. Ducrow M. Throwing light on blind intubation. Anaesthesia 1978; 33: 827-829. 3. Rayburn RL. "Light wand" intubation. Anaesthesia 1979; 34: 677-678. 4. Stone DJ, Stirt JA, Kaplan MJ, McLean W'C. A complication of lightwand-guided nasotracheal intubation. Anesthesiology 1984; 61: 780-781. 5. Weis FR jr, Kaiser RE. Lightwand-guided nasotracheal intubation is an effective technique. Anesthesiologv 1985; 62: 839-840. 6. Hammer M, Garry B. Transillumination of the trachea with Flexilum. Anesthesia and Analgesia 1985; 64: 91-92. 7. Vollmer TP, Stewart RD, Paris PM, Ellis DG, Berkebile PE. Use of a lighted stylet for guided orotracheal intubation in the prehospital setting. Annals of Emergency Medicine 1985; 14: 324-328. 8. Williams RT, Stewart RD. Transillumination of the trachea with a lighted stylet. Anesthesia and Analgesia 1986; 65: 542-543. 9. Ellis DG, Jakymec A, Kaplan RM, Stewart RD, Freeman JA, Bleyaert A, Berkebile PE. Guided orotracheal intubation in the operating room using a lighted stylet: a comparison with direct laryngoscopic technique. Anesthesiology 1986; 64: 823-826. 10. Fox DJ, Castro T jr, Rastrelli AJ. Comparison of intubation techniques in the awake patient: the FlexiLum surgical light (Lightwand) versus blind nasal approach. Anesthesiology 1987; 66: 69-71.
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015
Total
I
While others [7,8] have experience in Lightwand-guided intubation in emergency cases, we cannot make recommendations on its use in situations where the risk or regurgitation is high. The prevailing lighting conditions and the absence of direct laryngoscopic view preclude early recognition of regurgitation, and cricoid pressure may affect the ease of intubation. Other studies have shown that there is no increased incidence of major or minor complications with this technique compared with laryngoscopic intubation [7,9]. We re-used the same Tube-Stat for familiarization, throughout the study and subsequently for a total of 250 intubations. After each use, the stylet portion was sterilized with chlorhexidine in spirit 0.5",, w/v. There was a reduction in light intensity of our first device which was noticeable only when compared with a new unit. Note: The Tube-Stat is manufactured by Concept Incorporated (U.S.A.) and distributed by Henleys Medical Supplies Ltd (London). The unit costs £25.20 and it is designated as a "limited re-use instrument".
TRACHEAL INTUBATION 11. Stewart RD, Ellis DG. Lighted stylet and endotracheal intubation. I. Anesthesiology 1987; 66: 851. 12. Williams RT. Lighted stylet and endotracheal intubation. II. Anesthesiology 1987; 66: 851-852.
497 13. Mehta S. Guided orotracheal intubation in the operating room using a lighted stylet. Anesthesiology 1987; 66: 105. 14. Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39: 1105-1111.
Downloaded from http://bja.oxfordjournals.org/ at University of California, San Francisco on March 16, 2015