Anaesthesia, 1992, Volume 47, pages 729-73 1
Editorial Learning fibreoptic intubation: fundamental problems
Failed tracheal intubation still results in significant morbidity and mortality [I]. Several pre-operative tests have been proposed to identify patients at risk [2-51. However, these have not gained general acceptance because of the incidence of false-positive results [6]. In a recent article, Frerk assqsed two simple bedside tests for the prediction of difficult intubation and, in the cases studied, the two tests combined had a greater specificity than either test used alone [7]. If these tests taken together provide a more reliable method of predicting difficult intubation, how should such a patient be managed? A logical answer would be to perform an awake fibreoptic intubation. The availability of the fibreoptic bronchoscope represents a significant landmark in the search for a solution to difficult intubation. Several excellent articles have discussed the problem of how to instruct trainees in the technique [&lo], but for some hospitals, problems may appear at an even more fundamental level. A standard intubating bronchoscope, light source, adaptor, suction, sterilising equipment and purpose-built trolley costs about f10,OOO. The first hurdle may therefore be the initial purchase. A diagnostic and therapeutic return on this order of investment may not be immediately obvious. Managers, and sometimes colleagues in other specialties, may have to be convinced in the competition for limited equipment budgets. The case is probably best presented in a written submission, giving a succinct account of the clinical and medicolegal problems of failed intubation. Once acquired, the bronchoscope must be handled and maintained with care. It is a delicate instrument, consisting of insulated glass fibres bound into a flexible bundle. In addition there is a light guide cable, a working channel which is used for suction, local anaesthetic injection or oxygen insufflation, and angulation wires to allow movement of the tip in an anterior-posterior plane. Actual specifications such as length, diameter and tip angulation, can vary. Those designed for intubation tend to be longer (600 mm compared with 550 mm), of smaller diameter (4 mm compared with 5-6 mm), and possess lesser degrees of tip deflection and hence field of view (75’ compared with 90-1 20’), than diagnostic bronchoscopes. Meticulous handling, cleaning and sterilisation are essential, otherwise repair costs will be high. It is not an instrument for the casual, unsupervised user and so a strict policy on its availability may need to be defined. The insertion cord will only tolerate gentle bending. Light fibres are easily damaged and each additional individual broken one causes an incremental deterioration in the optical image. Forcible bending of the distal tip may fracture the control wires. Following use, a scrupulous and invariable routine must be observed. The bronchoscope must always be tested for leaks before immersion in sterilising solution as seepage through breaches in the external casing will cause major damage to the optical system. 0003-2409/92/090729
+03 $03.00/0
Before trainees can be taught to use the fibreoptic bronchoscope, senior members of staff must themselves first acquire the appropriate skills. Those who have learned by apprenticeship as a junior may underestimate the difficulty in acquiring a new skill, possibly unaided, as a consultant. Therefore, a priority is to provide opportunities for other senior staff to learn the technique. How should the technique be taught? Major differences appear to exist between the U K and the USA both in the teaching and practice of fibreoptic intubation. Local anaesthetic techniques seem to predominate in North America, whereas general anaesthesia features most commonly in the UK. There are disadvantages to teaching fibreoptic bronchoscopy under general anaesthesia. Two main techniques are used. In one, deep anaesthesia is achieved in the spontaneously breathing patient and the bronchoscope is usually, but not always, inserted through the mouth. Skilled assistance is required to maintain the airway and pollution of the anaesthetic room often occurs due to leaks. Reported complications include loss of airway control, desaturation, laryngeal spasm, bronchospasm and arrhythmias [ 1 I]. In the second, the bronchoscope is inserted under light anaesthesia during apnoea produced by neuromuscular blockade, a technique which leaves only a limited time for bronchoscopic insertion and tracheal intubation. After general anaesthesia has been induced, the soft palate, tongue and epiglottis approximate to the posterior pharyngeal wall [12]. Little air space is thus left in the oropharynx for manoeuvring the tip of the bronchoscope and the view tends to be obscured by the tissues. Several airways have been designed to overcome this problem and facilitate the insertion of the bronchoscope [13]. However, none of the approaches under general anaesthesia permit the unhurried, sequential identification of the nasal, pharyngeal and laryngeal structures, which is possible in the awake subject and essential when patients with abnormal anatomy or pathology are subsequently encountered. In addition, neither of the techniques prepare the trainee adequately to perform an awake fibreoptic intubation in a patient with a difficult airway. Dykes and Ovassapian [14] recommend that a trainee learns initially on awake patients who have normal anatomy, but acknowledge the problem of finding suitable subjects o n whom to gain experience. At their centre it became routine to perform an awake fibreoptic technique on all patients who required nasal intubation. If there are reservations about such an approach, the skills relevant to awake intubation may be acquired on patients undergoing diagnostic bronchoscopy. Such individuals readily accept that the ‘magic eye’ is used with local anaesthesia, and the judicious use of incremental doses of a diluted solution of midazolam usually ensures cooperation during the procedure and frequently amnesia as well. Large numbers of diagnostic bronchoscopies are
@ 1992 The Association of Anaesthetists of G t Britain and Ireland
729
730
Editorial
carried out each year, mostly under local anaesthesia and by physicians in respiratory medicine. In 1974 it was estimated that 15 000 patients a year in the UK might require diagnostic bronchoscopy [ 151. However, a postal survey, which had a 90% response rate, indicated that at least 40 000 of these procedures had been undertaken during 1983 [16]. Increased cooperation between physicians and anaesthetists is advantageous to both doctors and patients alike. The benefit of the presence of a second doctor when a procedure is being carried out under sedation is well recognised. In the postal survey, the commonest major complication (described as lifethreatening or a cause for concern) was respiratory depression from sedative-narcotic combinations. Routine administration of oxygen was confined to 18% cases, despite the fact that arterial desaturation frequently occurs during endoscopy under sedation. A consultant anaesthetist, supervising a trainee, could be responsible for the monitoring, sedation, administration of local anaesthesia, oxygenation and insertion of the bronchoscope through the vocal cords. Thereafter the physician would continue the procedure. The presence of the anaesthetist would permit the occasional very uncooperative patient to be given general anaesthesia, with the opportunity to offer reciprocal teaching of conventional tracheal intubation to members of the medical team. To what extent can the trainee be prepared before his first fibreoptic bronchoscopy on an awake patient? Undoubtedly, the most difficult task is to learn to hold, manipulate and advance the bronchoscope. Since the angulation produced by the tip lever is in one plane only, lateral movement of the fibrescope can only be achieved by rotation, followed by appropriate flexion and extension. The arrow on the perimeter of the field of view is an invaluable guide to the orientation of the instrument. Excellent books and papers on the technique are available [5, 171 and are worthy of careful attention beforehand. Familiarity with the anatomy is essential and study of bronchoscopic photographs, both normal and abnormal, of the epiglottis, vocal cords and trachea is helpful. The basic technique of handling of the instrument can be learned using an airway training model and bronchial tree. These are relatively inexpensive and many hospitals already possess them for resuscitation training purposes. Trainees undergoing a graduated training programme in fibreoptic bronchoscopy using such models, were shown to have a greater initial success rate with awake fibreoptic intubation than those without such preliminary preparation [18]. In addition, other important aspects such as sedation, local anaesthetic application, and insertion of the tracheal tube after bronchoscopy has been achieved, can all be taught before a real patient is encountered. There are other advantages to improving one’s dexterity on patients undergoing diagnostic bronchoscopy. Diagnostic bronchoscopes are of larger diameter than those designed for intubation and a better image and wider field of view is obtained. The usual approach is via the nasal route, so the angulation required to enter the larynx is less than that needed using an oral technique and the tongue does not interfere with insertion. Several useful tips can assist the beginner. When the nasal route is used, the position of the head and neck is important and differs from that required for conventional intubation. Full extension of the neck, either by removal of the pillow, or the use of a support under the shoulders, will open up the space around the glottis. The operator should insert a well-lubricated bronchoscope
into the more patent nostril and negotiate the nasal passages under direct vision. Discomfort, trauma and bleeding are thus minimised. Navigation along the floor of the nose, below the inferior turbinate, often brings the epiglottis directly into sight. Loss of view may occur in the pharynx, as a result of the tip abutting onto mucosa or being covered with blood or secretions. Vision is often restored by slight withdrawal of the fibrescope from the mucosa. Blood or secretions can usually be removed by suction, although on occasions, saline may need to be injected through the working channel, or the instrument completely withdrawn for cleaning. It is helpful to remember that, in adults, the distance between the nares and the epiglottis is about 15 cm. If structures are difficult to identify in the pharynx, the operator should be encouraged to pass the scope to about 12 cm, at which point recognisable structures often reappear. If the 15 cm mark has been passed and the glottis is still not visible, the bronchoscope is likely to be in the oesophagus. When the glottic structures have been identified, but difficulty is encountered passing the bronchoscope through the vocal cords, the patient should be asked to take a deep breath to bring about maximum abduction of the glottis. One of the commonest causes of failure of fibreoptic intubation is movement of the laryngeal structures as a result of inadequate topical anaesthesia [19]. In such cases further local anaesthetic should be introduced onto the vocal cords, via the working channel. Once the technique has been mastered in patients with normal anatomy, anaesthetists will be anxious to apply it to those in whom there are clinical indications. Fibreoptic intubation is not, however, the answer to every airway problem. The technique should not be applied uncritically, particularly if the operator is relatively inexperienced. A discussion on the indications and possible contraindications for bronchoscopy is therefore an essential part of training. The most appropriate candidate for awake fibreoptic intubation is the patient in whom the potential intubation difficulties are anatomical in origin, such that direct vision of the vocal cords is impossible using the conventional laryngoscope. Structural or pathological abnormalities involving the neck, mandible, maxilla, or teeth may contribute to these difficulties. Those patients in whom there is a risk of damage to teeth or dental work may also be suitable candidates, since dental claims form a significant proportion of anaesthetic medicolegal practice. Some suggested indications for fibreoptic intubation are more controversial. A case has recently been advanced for the awake intubation of all emergency patients who are at high risk from aspiration of gastric contents [20]. However, aspiration may still occur in the awake patient, and even the precaution of applying local anaesthetic only after the vocal cords have been visualised may not always protect a patient from massive regurgitation and aspiration. The use of the fibreoptic bronchoscope in patients with severe upper airway obstruction is also uncertain. Where there is critical upper airway narrowing as a result of oedema or tumours, instrumentation may precipitate complete obstruction even in the awake patient. Tumours may bleed or pieces might be directly dislodged by the bronchoscope. In the awake patient, interference with the upper airway in the presence of epiglottitis has traditionally been regarded as potentially dangerous. There are, however, advocates of awake intubation even in this condition [17]. It should be emphasised that such
Editorial techniques are only for the experienced bronchoscopist and the presence of an ENT surgeon prepared to perform emergency tracheostomy is mandatory. The aim of every anaesthetic department should be to provide a structured training programme in fibreoptic bronchoscopic intubation. Opportunities to cooperate with the chest physicians who provide diagnostic bronchoscopy services should be explored. The acquisition of confidence and skill in the technique will encourage an expansion of clinical indications. The threshold for the use of fibreoptic intubations should be lowered such that the technique is regularly practised and every anaesthetist becomes skilled in the art. Bedside tests for predicting intubation difficulty will only be of value if positive information elicits a logical response-if in doubt, intubate awake. Department of Anaesthesia Singleton Hosptial
R.A. MASON
Swansea SA2 8QA
References (1)KINGTA, ADAMSAP. Failed tracheal intubation. British Journal of Anaesthesia 1990; 6 5 400-14. [2]MALLAMPATI SR, GATT SP, GUGINOLD, DESAISP, WARAKSA B, FRIEBERGER D, LIU PL. A clinical sign to predict difficult tracheal intubation: a prospective study. Canadian Anaesthetists’ Society Journal 1985;32: 429-34. [3]SAMSOON GLT, YOUNG JRB. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987;4 2 487-90. [4]PATILVU, STEHLING LC, ZAUNDER HL. Fiberoptic endoscopy in Anesthesia. Chicago: Year Book Medical Publishers, 1983. (51 WIWN ME, SPIEGELHALTER D. ROBERTSON JA, LESSER P. Predicting difficult intubation. British Journal of Anaesthesia 1988;61: 21 1-6. [6]CHARTERS P, RRERA S, HORTON WA. Visibility of pharyn-
73 1
geal structures as a predictor of difficult intubation. Anaesthesia 1987;4 2 1 1 15. [IFRERKCM. Predicting difficult intubation. Anaesthesia
1991;46: 1005-8. A, DYKESMHM, GOLMAN ME. A training [8]OVASSAPIAN programme for fibreoptic nasotracheal intubation. Use of model and live patients. Anaesthesia 1983;38: 795-8. [9]DYKESMH, OVASSAPIAN A. Dissemination of fibreoptic airway endoscopy skills by means of a workshop utilizing models. British Journal of Anaesthesia 1989;63: 595-7. RS. Training in fibreoptic laryngoscopy. British [lo]VAUGHAN Journal of Anaesthesia 1991;66: 538-40. [ll]SMITHM, CALDERI, ISERTP, NICOLME, CROCKHARD HA. Oxygen saturation and cardiovascular changes during fibreoptic intubation under general anaesthesia. Anaesthesia 1992;47: 158-61. [12]NANDIPR, CHARLESWORTH CH, TAYLOR SJ, NUNNJF, DORECJ. Effect of general anaesthesia on the pharynx. British Journal of Anaesthesia 1991;66: 157-62. [I31 LATTOIP. Management of difficult intubation. In: LATTO IP, M ROSENeds. Dificulties in tracheal intubation London: Bailliere Tindall, 1985: 99-141. A. Teaching and learning [I41 DYKESMHM, OVASSAPIAN fiberoptic tracheal intubation. In: OVASSAPIAN A. Fiberoptic airway endoscopy in anesthesia and critical care. New York: Raven Press 1990: 163-8. [151 Anonymous. Safety and fibreoptic bronchoscopy. British Medical Journal 1974;iii: 542-3. [16]SIMPSONFG, ARNOLDAG, PURVIS A, BELP~ELDPW, M ~ RMF, S Coon NJ. Postal survey of bronchoscopic practice by physicians in the United Kingdom. Thorax 1986;41: 311-7. [ 171 OVASSAPIAN A. Fiberoptic airway endoscopy in anesthesia and critical care. New York: Raven Press 1990. [IS]OVASSAPIAN A. YELICHSJ, DYKMMHM, GOLMAN ME. Learning fibreoptic intubation; use of simulators v. traditional teaching. British Journal of Anaesthesia 1988;61:
217-20. [19]OVASSAPIAN A, YELICHSJ, DYKMMHM, BRUNNEREE. Fiberoptic naaotracheal intubation-incidence and causes of failure. Anesthesia and Analgesia 1983;6 2 692-5. [20]OVASSAPIAN A, KREJCIETC, YELICHSJ, DYKESMHM. Awake fibreoptic intubation in the patient at high risk of aspiration. British Journal of Anaesthesia 1989;6 2 13-6.
Editorial Learning fibreoptic intubation: fundamental problems
Failed tracheal intubation still results in significant morbidity and mortality [I]. Several pre-operative tests have been proposed to identify patients at risk [2-51. However, these have not gained general acceptance because of the incidence of false-positive results [6]. In a recent article, Frerk assqsed two simple bedside tests for the prediction of difficult intubation and, in the cases studied, the two tests combined had a greater specificity than either test used alone [7]. If these tests taken together provide a more reliable method of predicting difficult intubation, how should such a patient be managed? A logical answer would be to perform an awake fibreoptic intubation. The availability of the fibreoptic bronchoscope represents a significant landmark in the search for a solution to difficult intubation. Several excellent articles have discussed the problem of how to instruct trainees in the technique [&lo], but for some hospitals, problems may appear at an even more fundamental level. A standard intubating bronchoscope, light source, adaptor, suction, sterilising equipment and purpose-built trolley costs about f10,OOO. The first hurdle may therefore be the initial purchase. A diagnostic and therapeutic return on this order of investment may not be immediately obvious. Managers, and sometimes colleagues in other specialties, may have to be convinced in the competition for limited equipment budgets. The case is probably best presented in a written submission, giving a succinct account of the clinical and medicolegal problems of failed intubation. Once acquired, the bronchoscope must be handled and maintained with care. It is a delicate instrument, consisting of insulated glass fibres bound into a flexible bundle. In addition there is a light guide cable, a working channel which is used for suction, local anaesthetic injection or oxygen insufflation, and angulation wires to allow movement of the tip in an anterior-posterior plane. Actual specifications such as length, diameter and tip angulation, can vary. Those designed for intubation tend to be longer (600 mm compared with 550 mm), of smaller diameter (4 mm compared with 5-6 mm), and possess lesser degrees of tip deflection and hence field of view (75’ compared with 90-1 20’), than diagnostic bronchoscopes. Meticulous handling, cleaning and sterilisation are essential, otherwise repair costs will be high. It is not an instrument for the casual, unsupervised user and so a strict policy on its availability may need to be defined. The insertion cord will only tolerate gentle bending. Light fibres are easily damaged and each additional individual broken one causes an incremental deterioration in the optical image. Forcible bending of the distal tip may fracture the control wires. Following use, a scrupulous and invariable routine must be observed. The bronchoscope must always be tested for leaks before immersion in sterilising solution as seepage through breaches in the external casing will cause major damage to the optical system. 0003-2409/92/090729
+03 $03.00/0
Before trainees can be taught to use the fibreoptic bronchoscope, senior members of staff must themselves first acquire the appropriate skills. Those who have learned by apprenticeship as a junior may underestimate the difficulty in acquiring a new skill, possibly unaided, as a consultant. Therefore, a priority is to provide opportunities for other senior staff to learn the technique. How should the technique be taught? Major differences appear to exist between the U K and the USA both in the teaching and practice of fibreoptic intubation. Local anaesthetic techniques seem to predominate in North America, whereas general anaesthesia features most commonly in the UK. There are disadvantages to teaching fibreoptic bronchoscopy under general anaesthesia. Two main techniques are used. In one, deep anaesthesia is achieved in the spontaneously breathing patient and the bronchoscope is usually, but not always, inserted through the mouth. Skilled assistance is required to maintain the airway and pollution of the anaesthetic room often occurs due to leaks. Reported complications include loss of airway control, desaturation, laryngeal spasm, bronchospasm and arrhythmias [ 1 I]. In the second, the bronchoscope is inserted under light anaesthesia during apnoea produced by neuromuscular blockade, a technique which leaves only a limited time for bronchoscopic insertion and tracheal intubation. After general anaesthesia has been induced, the soft palate, tongue and epiglottis approximate to the posterior pharyngeal wall [12]. Little air space is thus left in the oropharynx for manoeuvring the tip of the bronchoscope and the view tends to be obscured by the tissues. Several airways have been designed to overcome this problem and facilitate the insertion of the bronchoscope [13]. However, none of the approaches under general anaesthesia permit the unhurried, sequential identification of the nasal, pharyngeal and laryngeal structures, which is possible in the awake subject and essential when patients with abnormal anatomy or pathology are subsequently encountered. In addition, neither of the techniques prepare the trainee adequately to perform an awake fibreoptic intubation in a patient with a difficult airway. Dykes and Ovassapian [14] recommend that a trainee learns initially on awake patients who have normal anatomy, but acknowledge the problem of finding suitable subjects o n whom to gain experience. At their centre it became routine to perform an awake fibreoptic technique on all patients who required nasal intubation. If there are reservations about such an approach, the skills relevant to awake intubation may be acquired on patients undergoing diagnostic bronchoscopy. Such individuals readily accept that the ‘magic eye’ is used with local anaesthesia, and the judicious use of incremental doses of a diluted solution of midazolam usually ensures cooperation during the procedure and frequently amnesia as well. Large numbers of diagnostic bronchoscopies are
@ 1992 The Association of Anaesthetists of G t Britain and Ireland
729
730
Editorial
carried out each year, mostly under local anaesthesia and by physicians in respiratory medicine. In 1974 it was estimated that 15 000 patients a year in the UK might require diagnostic bronchoscopy [ 151. However, a postal survey, which had a 90% response rate, indicated that at least 40 000 of these procedures had been undertaken during 1983 [16]. Increased cooperation between physicians and anaesthetists is advantageous to both doctors and patients alike. The benefit of the presence of a second doctor when a procedure is being carried out under sedation is well recognised. In the postal survey, the commonest major complication (described as lifethreatening or a cause for concern) was respiratory depression from sedative-narcotic combinations. Routine administration of oxygen was confined to 18% cases, despite the fact that arterial desaturation frequently occurs during endoscopy under sedation. A consultant anaesthetist, supervising a trainee, could be responsible for the monitoring, sedation, administration of local anaesthesia, oxygenation and insertion of the bronchoscope through the vocal cords. Thereafter the physician would continue the procedure. The presence of the anaesthetist would permit the occasional very uncooperative patient to be given general anaesthesia, with the opportunity to offer reciprocal teaching of conventional tracheal intubation to members of the medical team. To what extent can the trainee be prepared before his first fibreoptic bronchoscopy on an awake patient? Undoubtedly, the most difficult task is to learn to hold, manipulate and advance the bronchoscope. Since the angulation produced by the tip lever is in one plane only, lateral movement of the fibrescope can only be achieved by rotation, followed by appropriate flexion and extension. The arrow on the perimeter of the field of view is an invaluable guide to the orientation of the instrument. Excellent books and papers on the technique are available [5, 171 and are worthy of careful attention beforehand. Familiarity with the anatomy is essential and study of bronchoscopic photographs, both normal and abnormal, of the epiglottis, vocal cords and trachea is helpful. The basic technique of handling of the instrument can be learned using an airway training model and bronchial tree. These are relatively inexpensive and many hospitals already possess them for resuscitation training purposes. Trainees undergoing a graduated training programme in fibreoptic bronchoscopy using such models, were shown to have a greater initial success rate with awake fibreoptic intubation than those without such preliminary preparation [18]. In addition, other important aspects such as sedation, local anaesthetic application, and insertion of the tracheal tube after bronchoscopy has been achieved, can all be taught before a real patient is encountered. There are other advantages to improving one’s dexterity on patients undergoing diagnostic bronchoscopy. Diagnostic bronchoscopes are of larger diameter than those designed for intubation and a better image and wider field of view is obtained. The usual approach is via the nasal route, so the angulation required to enter the larynx is less than that needed using an oral technique and the tongue does not interfere with insertion. Several useful tips can assist the beginner. When the nasal route is used, the position of the head and neck is important and differs from that required for conventional intubation. Full extension of the neck, either by removal of the pillow, or the use of a support under the shoulders, will open up the space around the glottis. The operator should insert a well-lubricated bronchoscope
into the more patent nostril and negotiate the nasal passages under direct vision. Discomfort, trauma and bleeding are thus minimised. Navigation along the floor of the nose, below the inferior turbinate, often brings the epiglottis directly into sight. Loss of view may occur in the pharynx, as a result of the tip abutting onto mucosa or being covered with blood or secretions. Vision is often restored by slight withdrawal of the fibrescope from the mucosa. Blood or secretions can usually be removed by suction, although on occasions, saline may need to be injected through the working channel, or the instrument completely withdrawn for cleaning. It is helpful to remember that, in adults, the distance between the nares and the epiglottis is about 15 cm. If structures are difficult to identify in the pharynx, the operator should be encouraged to pass the scope to about 12 cm, at which point recognisable structures often reappear. If the 15 cm mark has been passed and the glottis is still not visible, the bronchoscope is likely to be in the oesophagus. When the glottic structures have been identified, but difficulty is encountered passing the bronchoscope through the vocal cords, the patient should be asked to take a deep breath to bring about maximum abduction of the glottis. One of the commonest causes of failure of fibreoptic intubation is movement of the laryngeal structures as a result of inadequate topical anaesthesia [19]. In such cases further local anaesthetic should be introduced onto the vocal cords, via the working channel. Once the technique has been mastered in patients with normal anatomy, anaesthetists will be anxious to apply it to those in whom there are clinical indications. Fibreoptic intubation is not, however, the answer to every airway problem. The technique should not be applied uncritically, particularly if the operator is relatively inexperienced. A discussion on the indications and possible contraindications for bronchoscopy is therefore an essential part of training. The most appropriate candidate for awake fibreoptic intubation is the patient in whom the potential intubation difficulties are anatomical in origin, such that direct vision of the vocal cords is impossible using the conventional laryngoscope. Structural or pathological abnormalities involving the neck, mandible, maxilla, or teeth may contribute to these difficulties. Those patients in whom there is a risk of damage to teeth or dental work may also be suitable candidates, since dental claims form a significant proportion of anaesthetic medicolegal practice. Some suggested indications for fibreoptic intubation are more controversial. A case has recently been advanced for the awake intubation of all emergency patients who are at high risk from aspiration of gastric contents [20]. However, aspiration may still occur in the awake patient, and even the precaution of applying local anaesthetic only after the vocal cords have been visualised may not always protect a patient from massive regurgitation and aspiration. The use of the fibreoptic bronchoscope in patients with severe upper airway obstruction is also uncertain. Where there is critical upper airway narrowing as a result of oedema or tumours, instrumentation may precipitate complete obstruction even in the awake patient. Tumours may bleed or pieces might be directly dislodged by the bronchoscope. In the awake patient, interference with the upper airway in the presence of epiglottitis has traditionally been regarded as potentially dangerous. There are, however, advocates of awake intubation even in this condition [17]. It should be emphasised that such
Editorial techniques are only for the experienced bronchoscopist and the presence of an ENT surgeon prepared to perform emergency tracheostomy is mandatory. The aim of every anaesthetic department should be to provide a structured training programme in fibreoptic bronchoscopic intubation. Opportunities to cooperate with the chest physicians who provide diagnostic bronchoscopy services should be explored. The acquisition of confidence and skill in the technique will encourage an expansion of clinical indications. The threshold for the use of fibreoptic intubations should be lowered such that the technique is regularly practised and every anaesthetist becomes skilled in the art. Bedside tests for predicting intubation difficulty will only be of value if positive information elicits a logical response-if in doubt, intubate awake. Department of Anaesthesia Singleton Hosptial
R.A. MASON
Swansea SA2 8QA
References (1)KINGTA, ADAMSAP. Failed tracheal intubation. British Journal of Anaesthesia 1990; 6 5 400-14. [2]MALLAMPATI SR, GATT SP, GUGINOLD, DESAISP, WARAKSA B, FRIEBERGER D, LIU PL. A clinical sign to predict difficult tracheal intubation: a prospective study. Canadian Anaesthetists’ Society Journal 1985;32: 429-34. [3]SAMSOON GLT, YOUNG JRB. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987;4 2 487-90. [4]PATILVU, STEHLING LC, ZAUNDER HL. Fiberoptic endoscopy in Anesthesia. Chicago: Year Book Medical Publishers, 1983. (51 WIWN ME, SPIEGELHALTER D. ROBERTSON JA, LESSER P. Predicting difficult intubation. British Journal of Anaesthesia 1988;61: 21 1-6. [6]CHARTERS P, RRERA S, HORTON WA. Visibility of pharyn-
73 1
geal structures as a predictor of difficult intubation. Anaesthesia 1987;4 2 1 1 15. [IFRERKCM. Predicting difficult intubation. Anaesthesia
1991;46: 1005-8. A, DYKESMHM, GOLMAN ME. A training [8]OVASSAPIAN programme for fibreoptic nasotracheal intubation. Use of model and live patients. Anaesthesia 1983;38: 795-8. [9]DYKESMH, OVASSAPIAN A. Dissemination of fibreoptic airway endoscopy skills by means of a workshop utilizing models. British Journal of Anaesthesia 1989;63: 595-7. RS. Training in fibreoptic laryngoscopy. British [lo]VAUGHAN Journal of Anaesthesia 1991;66: 538-40. [ll]SMITHM, CALDERI, ISERTP, NICOLME, CROCKHARD HA. Oxygen saturation and cardiovascular changes during fibreoptic intubation under general anaesthesia. Anaesthesia 1992;47: 158-61. [12]NANDIPR, CHARLESWORTH CH, TAYLOR SJ, NUNNJF, DORECJ. Effect of general anaesthesia on the pharynx. British Journal of Anaesthesia 1991;66: 157-62. [I31 LATTOIP. Management of difficult intubation. In: LATTO IP, M ROSENeds. Dificulties in tracheal intubation London: Bailliere Tindall, 1985: 99-141. A. Teaching and learning [I41 DYKESMHM, OVASSAPIAN fiberoptic tracheal intubation. In: OVASSAPIAN A. Fiberoptic airway endoscopy in anesthesia and critical care. New York: Raven Press 1990: 163-8. [151 Anonymous. Safety and fibreoptic bronchoscopy. British Medical Journal 1974;iii: 542-3. [16]SIMPSONFG, ARNOLDAG, PURVIS A, BELP~ELDPW, M ~ RMF, S Coon NJ. Postal survey of bronchoscopic practice by physicians in the United Kingdom. Thorax 1986;41: 311-7. [ 171 OVASSAPIAN A. Fiberoptic airway endoscopy in anesthesia and critical care. New York: Raven Press 1990. [IS]OVASSAPIAN A. YELICHSJ, DYKMMHM, GOLMAN ME. Learning fibreoptic intubation; use of simulators v. traditional teaching. British Journal of Anaesthesia 1988;61:
217-20. [19]OVASSAPIAN A, YELICHSJ, DYKMMHM, BRUNNEREE. Fiberoptic naaotracheal intubation-incidence and causes of failure. Anesthesia and Analgesia 1983;6 2 692-5. [20]OVASSAPIAN A, KREJCIETC, YELICHSJ, DYKESMHM. Awake fibreoptic intubation in the patient at high risk of aspiration. British Journal of Anaesthesia 1989;6 2 13-6.
