Br.J. Anaesth. (1975), 47, 1219
ANAESTHESIA FOR FIBREOPTIC BRONCHOSCOPY F. I. MACNAUGHTON SUMMARY
Fibreoptic bronchoscopy is a useful diagnostic aid but may result in difficulties when associated with endotracheal anaesthesia. As a result, adequate ventilation may be difficult in patients with impaired pulmonary function and, in particular, in female patients because of the smaller size of the laryngeal opening. In a trial of three methods of endotracheal anaesthesia in a series of 39 patients, a direct catheter inflation technique gave satisfactory ventilation without circulatory depression.
MATERIALS AND METHODS
Number 8 (8 mm i.d.) endotracheal tubes were inserted in female patients (method I). Using a rigid tracheoscope fitted with an endotracheal cuff, the fibreoptic bronchoscope was passed through a rubber diaphragm over the proximal end. Ventilation with anaesthetic gases was performed via a side-arm on the tracheoscope. The tracheoscope has the advantage of being thinner-walled than a conventional endotracheal tube (method II). A high-pressure direct tracheal injection ventilation method was used. This was an adaptation of Carden and Crutchfield's (1973) catheter modification of Sanders (1967), Spoerel (1969), Spoerel, Narayanan and Singh (1971), and Spoerel and Greenway (1973) high-pressure injector techniques. In each patient the trachea was intubated with a double-lumen tube. This was constructed by taping, for ventilation, a small lumen No. 00 (3 mm i.d.) Magill tube to a larger (6.5 mm i.d.) plain endotracheal tube, the latter being just large enough for the fibreoptic instrument to pass through. The smaller tube had a Luer fitting proximally and was fixed so that the tip was on the concave side of, and near the tip of, the larger tube (fig. 1). No lesions of the tracheal mucosa resulted from the use of this arrangement (method III).
The method described by Tahir (1972) using a Y- or T-piece was studied. The fibreoptic bronchoscope was passed through a small slit in the rubber diaphragm covering one arm of the Y- or T-piece, the anaesthetic being administered through the other or side-arm. A conventional cuffed endotracheal tube was attached to the leg of the Y- or T-piece. F. I. MACNAUGHTON, Department of Anaesthesia, Bispebjerg Hospital, 2400 Copenhagen NV, Denmark.
FIG. 1. The double-lumen intubation tube.
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Fibreoptic bronchoscopy has improved the detection of bronchial carcinoma especially of peripherally situated tumours (Ikeda, Noboru and Scichiro, 1968; Borgeskov, Becker and Pedersen, 1973), and those in the upper lobes (Ikeda, 1970). The bronchoscopy can be performed in some patients with sedation and local analgesia (Wanner, Amikam and Sackner, 1972), although there are few patients who do not experience a degree of discomfort (Grant, 1974). There remain patients for whom general anaesthesia is desirable (Editorial, 1974). The solid nature of the fibreoptic instrument may result in a dangerous degree of obstruction to the airway in patients suffering from pulmonary disease. A trial of three different techniques of administering general anaesthesia was performed in a series of 39 patients to find the most suitable method. There was no selection of patients, but the first patient in each group was a male, and a new group was not started until a patient in reasonable health was available to initiate the method. Blood-gas tensions were measured (Radiometer, Copenhagen). Arterial pressure was monitored by repeated sphygmomanometric measurements.
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FIG. 2. Apparatus for direct catheter inflation ventilation.
The "Oxymix" (measuring 8.5 x 6 x 5 cm) is made for the blending of independent central supply outlets of oxygen and compressed air, and is adjustable to yield oxygen concentrations of from 2 1 % to 100%. Two flow rates are available, either at less than 25 litre/min or between 25 and 100 litre/min, selected by turning the control knob clockwise or anticlockwise. The "Oxymix" is easily calibrated for mixing oxygen and nitrous oxide. The Teknova Mini regulator (Teknova, Niva, Denmark) is a compact ( 6 x 3 cm) "piston"-type pressure reducer, with a range of 0-8 atm, and can be fixed directly to the outlet of the "Oxymix".
The on/off valve used was a commercially produced (EWO) pistol-type with trigger release and springreturn off. Such valves are used commonly in automobile garages for tyre inflation. Although cumbersome, it is very easy to use, with a light but positive action. Anaesthesia The first 20 patients were not premedicated, the remainder were premedicated using morphine and hyoscine. Atropine was given intravenously just before induction. In all patients anaesthesia was induced with thiopentone, which was followed by suxamethonium. Maintenance of anaesthesia was with nitrous oxide in oxygen and halothane for methods I and II, and by nitrous oxide in oxygen and supplements of thiopentone in method III. All groups received suxamethonium by intravenous infusion (2 mg/ml in physiological saline) after the initial dose at induction. Groups I and II were ventilated using a Barnet Mk III ventilator, time-cycled as a minute volume divider. The tidal volume was calculated according to the Radford nomogram (Radford, Ferris and Kriete, 1954) plus 25% of the calculated volume, measured as the expiratory tidal volume by the flowmeter on the ventilator. The pressure developed in the endotracheal tube was measured via a side-arm. The inspiratory/expiratory ratio was adjusted to give the best result obtainable for the individual patient, as judged by tracheal pressure and expiratory tidal volume, although the inspiratory phase was always long enough to give an end-inspiratory plateau for an approximate determination of the alveolar pressure. Halothane 1 % was given for 5 min and thereafter maintained at 0.5%. The administration was stopped in some patients when arterial hypotension failed to respond to intravenous fluid therapy with Ringer's lactate solution. For the catheter inflation ventilation nitrous oxide and oxygen from independent sources were used, each delivered to the "Oxymix" at a pressure in excess of 4 atm abs. Tidal volumes and intratracheal pressures were not measured. However, before using this method, trials were performed using a variety of models based on a large carboy to represent lung compliance (Mushin et al., 1969). After cannulation of the radial or brachial artery, samples for blood-gas measurement were taken before induction Further samples were taken after 10 min
Downloaded from http://bja.oxfordjournals.org/ at University of Chicago on July 5, 2015
Apparatus The apparatus for the direct catheter inflation ventilation (fig. 2) consisted of an "Oxymix" mixing chamber (Simonsen & Weel, Copenhagen) with its two inlets connected to sources of oxygen and nitrous oxide respectively. The "Oxymix" permitted the oxygen: nitrous oxide ratio to be varied. The outlet of the mixing chamber was connected to an adjustable pressure reduction valve (Teknova Mini Regulator 236 A) for control of the injection pressure. From this was taken a suitable length of tubing with a pistol-type on/off valve at the distal end. This valve was fitted with a Luer lock on the outlet to match the Luer fitting of the inflation tube.
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ANAESTHESIA FOR FIBREOPTIC BRONCHOSCOPY TABLE I. Measured indices in male patients of groups I, II and III (range of values in parentheses)
Age(yr) Duration of anaesthesia (min) Duration of bronchoscopy (min) Mean arterial pressure (mm Hg) Pre-induction Post-intubation Least during bronchoscopy Tidal volume (ml) Change in alveolar pressure (cm H2O) Paco,
Start of bronchoscopy
Paco,
During bronchoscopy Lowest value
Paco,
Highest value
Pa
co, Pa0>
Group II (5 patients)
Group III (6 patients)
57 (40-68) 50 (36-65) 23 (16-38)
63 (53-73) 34 (28-47)
65 (54-74) 40 (28-65) 31 (21-47)
23 (20-25)
118 (80-155) 110 (70-145) 86 (50-110) 526 (400-650) + 3 (0 to +9)
101 (90-110) 103 (90-120) 136 (85-150) 128(120-140) 84 (55-110) 103 (95-120) 560 (450-650) + 3 ( + l to +6)
38 80 37 137
(31-45) (65-92) (31-48) (75-250)
40 (35-43) 67 (52-75) 38 (31-46) 137 (115-155)
39 (34-45) 82 (66-90) 40 (23-54) 162 (106-240)
39 116 46 134
(31-50) (83-210) (31-54) (83-235)
31 (26-35) 87 (76-98) 35 (29-41) 125 (100-204)
32 (19-39) 163 (71-240) 36 (29-43) 234 (138-330)
ventilation by the Barnet ventilator for methods I and II, or immediately after the passing of the fibreoptic bronchoscope in method III, and thereafter at 5-min intervals until the bronchoscopy was completed. All patients were observed in the recovery room for at least 1 hr, a final blood-gas sample being taken before return to the ward. The duration of anaesthesia was taken as from the time of induction until the patient could respond adequately to the command to lift the head from the pillow. The ratio of oxygen to nitrous oxide was 1 : 2, but in two patients this was changed to 1 : 1, and in one to 2 : 1 , where the patients (all female group I) appeared to be cyanosed. The bronchoscopic examination had to be interrupted temporarily for two of these patients. RESULTS
In tables I and II the sexes are separated, and divided into male groups I, II and III, corresponding to methods I, II and III, and female groups I and III. Method II was not used for the female patients. Male patients In most respects, the results for groups I and II are comparable.
TABLE II. Measured indices in female patients of groups I and HI (range of values in parentheses)
Age (yr) Duration of anaesthesia (min) Duration of bronchoscopy (min) Mean arterial pressure (mmHg) Pre-induction Post-intubation Least during bronchoscopy Tidal volume (ml) Change in alveolar pressure (cm
Group I (11 patients)
Group III (5 patients)
66.7 (55-81) 52 (43-67)
57 (42-66) 40 (35-58)
19 (11-31)
26 (22-30)
125 (85-190) 115 (75-180) 84 (60-135)
103 (80-140) 121 (100-140) 105 (85-150)
450 (370-550) + 10 ( + 2 to +14)
Blood-gases (mm Hg) 38 (33-43) Pre-induction , 38 (36-^3) 72 (59-86) 84 (75-95) Pao, Start of bronchoscopy 38 (29-51) Paco, 38 (31-47) Pao, 124 (57-195) 112 (75-158) During bronchoscopy 29 (22-33) Lowest value Paco, 42 (32-56) 98 (53-168) 118 (90-176) Pao, Highest value PaCo, 48 (39-76) 34 (28-39) Pa,0, 128 (85-230) 189 (100-210)
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Blood-gases (mm Hg) Pre-induction
Group I (12 patients)
BRITISH JOURNAL OF ANAESTHESIA
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Females
Group I females showed poorer results than in the males, with increased alveolar pressure, circulatory depression and several unsatisfactory blood-gas values. In group III females satisfactory blood-gas tensions were obtained, there was no arterial hypotension, and the fibreoptic procedures were completed without hindrance. DISCUSSION
As the difference between groups I and II is really only that of the material from which the endotracheal tube is made, it is not surprising that the results in these groups are similar. However in group II, after an initial increase in Pa Oj during 10 min of normal ventilation, there occurred a curious tendency for the Pa o , to decrease following the start of the bronchoscopy, and this was progressive in four of the five patients. Because of the risk of laryngeal trauma it was considered undesirable to use endotracheal tubes larger than 8 mm i.d. in the female patients (Dam and Zwergius, 1952). The tracheoscope, which also has the disadvantage of being rigid, was not used in the female patients on account of its size (12 mm o.d.), and because of the decrease in oxygen tension found in the male group II patients. Although the results were satisfactory for some of the female patients in group I, it can be seen that the increased alveolar pressure was accompanied by arterial hypotension similar to that found in the male patients. The blood-gas values were unsatisfactory, with increases in Pa COj , and decreases in Pa Oj to hypoxic values in three patients who had large pulmonary lesions.
The female group III patients all had satisfactory blood-gas tensions without circulatory depression. Satisfactory results were achieved with the three methods in the male patients. Method I was not satisfactory for the female patients. The reduction of cross-sectional area caused by the solid fibreoptic bronchoscope passing through a conventional tube in the male may be up to 25%. In the female it is nearer 45%, which, because of the curvature of the tube and especially in conjunction with reduced pulmonary function, may lead to inadequate ventilation. However, the use of catheter inflation ventilation appears to offer a better alternative. It is relatively easy to hyperventilate the patients, as can be seen from the decrease in Pa COj during bronchoscopy. However, certain precautions should be taken. Under testing, it was found that the length of the injection period was a decisive factor in determining the amount of the increase in intrathoracic pressure. Thus the duration of the inspiratory phase must be kept short (less than 1 sec). There must be no increase in resistance to expiration, for example as a result of laryngeal spasm round the tube since, when the bronchoscope is inserted through the larger bore tubes it is essential for at least part of the expiratory gases to pass via the outside of the tube. Vigilance is required to prevent returning laryngeal muscle tone from closing the glottis. This can be detected by an alteration in the quality of the sound of the expiratory phase and it may also become noisier. A hand resting lightly on the abdomen may feel a slight rebound immediately after the inspiratory phase is over. This would indicate that an increase in the rate of the suxamethonium infusion is required. Our surgical colleagues preferred the catheter inflation ventilation as, in their opinion, it gave better dilatation of the bronchial tree, especially in the female patients. ACKNOWLEDGEMENTS
Simonsen and Weel, Copenhagen (British address: Simonsen & Weel Ltd, Hatherley House, Hatherley Road, Sidcup, Kent) loaned the "Oxymix" mixing chamber, reduction valve and pistol-type release valve. Mrs Ellen Kaufman and Miss Doris Hansen measured blood-gas tensions. Thanks are also given to surgical colleagues of the Department of Thoracic Surgery and the anaesthetic nurses of Bispebjerg Hospital, Copenhagen. Dr W. H. Dam, consultant in charge, Department of Anaesthesia, gave helpful criticism and advice. REFERENCES
Borgeskov, S., Becker, J., and Pedersen, A. B. (1973). The flexible broncho-fiberscope. Endoscopy, 5, 177. Carden, E., and Crutchfield, W. (1973). Anaesthesia for microsurgery of the larynx. Can. Anaesth. Soc.J., 20, 378.
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The rather longer recovery for group I was probably a result of the continuation of halothane administration until the examination was complete, while the end-point of the bronchoscopy was better estimated in group II. Group III patients showed a quicker recovery, as might be expected. The arterial pressure decreased during anaesthesia in both groups I and II. There was no decrease in arterial pressure in the group III patients. Although the blood-gas tensions revealed no serious abnormalities in groups I and II, higher PaOi tensions were measured in the group III patients. There was a decrease in Pa COi in all the group III patients during bronchoscopy.
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ANAESTHESIA FOR FIBREOPTIC BRONCHOSCOPY
ANESTHESIE POUR BRONCHOSCOPIE FIBREOPTIQUE RESUME
La bronchoscopie fibreoptique est une aide utile pour la formulation des diagnostics, mais elle peut entrainer
certaines difficultes lorsqu'on l'associe a l'anesthesie endotracheale. De ce fait, une ventilation adequate des malades peut-etre difficile lorsque ceux-ci souffrent d'une mauvaise fonction pulmonaire et en particulier chez les femmes en raison des petites dimensions des ouvertures de leur larynx. Dans les essais que Ton a effectues sur trois methodes d'anesthesie endotracheale, sur 39 malades, la technique directe de dilatation du catheter a assure une ventilation satisfaisante sans aucune depression circulatoire. ANASTHESIE FUR FASERNOPTIKBRONCHOSKOPIE ZUSAMMENFASSUNG
Fasernoptik-Bronchoskopie ist eine nutzliche Diagnosehilfe, kann aber zu Schwierigkeiten fuhren, wenn sie mit endotrachealer Anasthesie verwendet wird. Daher kann eine ausreichende Beluftung bei Patienten mit verminderter Lungenfunktion schwierig sein, besonders bei weiblichen Patienten, aufgrund der geringeren Grosse ihrer Kehlkopfoffnungen. Bei einem Versuch mit drei Methoden endotrachealer Anasthesie bei 39 Patienten ergab eine direkte Katheter-Fullungsmethode eine zufriedenstellende Beluftung ohne Kreislaufhemmung. ANESTESIA POR BRONCOSCOPIA FIBRAOPTICA SUMARIO
La broncoscopia fibraoptica es una ayuda diagnostica util, pero puede producir dificultades cuando se relaciona con la anestesia endotraqueal. En consecuencia puede ser dificiluna ventilacion adecuada en pacientes con una funcion pulmonar deteriorada y, en especial, en pacientes femeninos a causa del tamano menor de la apertura de sus laringes. En un experimento de los tres metodos de anestesia endotraqueal en una serie de 39 pacientes, la tecnica de insuflacion directa del cateter produjo una ventilacion satisfactoria con depresion circulatoria.
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Dam, W.j and Zwergius, E. (1952). Laryngeale komplikationer efter langvarig endotracheal intubation af narkotisk forgiftede patienter. Nord. Med., 48, 1095. Editorial (1974). Safety and fibreoptic bronchoscopy. Br. Med. J., 3, 542. Grant, I. W. B. (1974). Safety and fibreoptic bronchoscopy. Br. Med. J., 4, 464. Ikeda, S. (1970). Flexible bronchofiberscope, presented at the meeting of the American Broncho-esophagological Association, Florida, 20-21 April. Noboru, Y., and Scichiro, I. (1968). Flexible bronchonberscopcKeioJ1. Med., 17, 1. Mushin, W. W., Rendell-Baker, L., Thompson, P. W., and Mapleson, W. W. (1969). Automatic Ventilation of the Lung, 2nd edn., p. 179. Oxford and Edinburgh: Blackwell. Radford, E. P., jr, Ferris, B. G., jr, and Kriete, B. C. (1954). Clinical use of a nomogram to estimate proper ventilation during artificial respiration. JV. Engl. J. Med., 251, 877. Sanders, R. D. (1967). Two ventilating attachments for bronchoscopes. Del. Med.J., 39, 170. Spoerel, W. E. (1969). Ventilation through an open bronchoscope. Can. Anaesth. Soc.J., 16, 61. Greenway, R. E. (1973). Technique of ventilation during endolaryngeal surgery under general anaesthesia. Can. Anaesth. Soc. J., 20, 369. Narayanan, P. S., and Singh, N. P. (1971). Transtracheal ventilation. Br. J. Anaesth., 43, 932. Tahir, A. H. (1972). General anesthesia for bronchofiberscopy. Anesthesiology, 37, 564. Wanner, A., Amikam, B., and Sackner, M. A. (1972). A technique for bedside bronchofiberscopy. Chest, 61, 287.
ANAESTHESIA FOR FIBREOPTIC BRONCHOSCOPY F. I. MACNAUGHTON SUMMARY
Fibreoptic bronchoscopy is a useful diagnostic aid but may result in difficulties when associated with endotracheal anaesthesia. As a result, adequate ventilation may be difficult in patients with impaired pulmonary function and, in particular, in female patients because of the smaller size of the laryngeal opening. In a trial of three methods of endotracheal anaesthesia in a series of 39 patients, a direct catheter inflation technique gave satisfactory ventilation without circulatory depression.
MATERIALS AND METHODS
Number 8 (8 mm i.d.) endotracheal tubes were inserted in female patients (method I). Using a rigid tracheoscope fitted with an endotracheal cuff, the fibreoptic bronchoscope was passed through a rubber diaphragm over the proximal end. Ventilation with anaesthetic gases was performed via a side-arm on the tracheoscope. The tracheoscope has the advantage of being thinner-walled than a conventional endotracheal tube (method II). A high-pressure direct tracheal injection ventilation method was used. This was an adaptation of Carden and Crutchfield's (1973) catheter modification of Sanders (1967), Spoerel (1969), Spoerel, Narayanan and Singh (1971), and Spoerel and Greenway (1973) high-pressure injector techniques. In each patient the trachea was intubated with a double-lumen tube. This was constructed by taping, for ventilation, a small lumen No. 00 (3 mm i.d.) Magill tube to a larger (6.5 mm i.d.) plain endotracheal tube, the latter being just large enough for the fibreoptic instrument to pass through. The smaller tube had a Luer fitting proximally and was fixed so that the tip was on the concave side of, and near the tip of, the larger tube (fig. 1). No lesions of the tracheal mucosa resulted from the use of this arrangement (method III).
The method described by Tahir (1972) using a Y- or T-piece was studied. The fibreoptic bronchoscope was passed through a small slit in the rubber diaphragm covering one arm of the Y- or T-piece, the anaesthetic being administered through the other or side-arm. A conventional cuffed endotracheal tube was attached to the leg of the Y- or T-piece. F. I. MACNAUGHTON, Department of Anaesthesia, Bispebjerg Hospital, 2400 Copenhagen NV, Denmark.
FIG. 1. The double-lumen intubation tube.
Downloaded from http://bja.oxfordjournals.org/ at University of Chicago on July 5, 2015
Fibreoptic bronchoscopy has improved the detection of bronchial carcinoma especially of peripherally situated tumours (Ikeda, Noboru and Scichiro, 1968; Borgeskov, Becker and Pedersen, 1973), and those in the upper lobes (Ikeda, 1970). The bronchoscopy can be performed in some patients with sedation and local analgesia (Wanner, Amikam and Sackner, 1972), although there are few patients who do not experience a degree of discomfort (Grant, 1974). There remain patients for whom general anaesthesia is desirable (Editorial, 1974). The solid nature of the fibreoptic instrument may result in a dangerous degree of obstruction to the airway in patients suffering from pulmonary disease. A trial of three different techniques of administering general anaesthesia was performed in a series of 39 patients to find the most suitable method. There was no selection of patients, but the first patient in each group was a male, and a new group was not started until a patient in reasonable health was available to initiate the method. Blood-gas tensions were measured (Radiometer, Copenhagen). Arterial pressure was monitored by repeated sphygmomanometric measurements.
1220
FIG. 2. Apparatus for direct catheter inflation ventilation.
The "Oxymix" (measuring 8.5 x 6 x 5 cm) is made for the blending of independent central supply outlets of oxygen and compressed air, and is adjustable to yield oxygen concentrations of from 2 1 % to 100%. Two flow rates are available, either at less than 25 litre/min or between 25 and 100 litre/min, selected by turning the control knob clockwise or anticlockwise. The "Oxymix" is easily calibrated for mixing oxygen and nitrous oxide. The Teknova Mini regulator (Teknova, Niva, Denmark) is a compact ( 6 x 3 cm) "piston"-type pressure reducer, with a range of 0-8 atm, and can be fixed directly to the outlet of the "Oxymix".
The on/off valve used was a commercially produced (EWO) pistol-type with trigger release and springreturn off. Such valves are used commonly in automobile garages for tyre inflation. Although cumbersome, it is very easy to use, with a light but positive action. Anaesthesia The first 20 patients were not premedicated, the remainder were premedicated using morphine and hyoscine. Atropine was given intravenously just before induction. In all patients anaesthesia was induced with thiopentone, which was followed by suxamethonium. Maintenance of anaesthesia was with nitrous oxide in oxygen and halothane for methods I and II, and by nitrous oxide in oxygen and supplements of thiopentone in method III. All groups received suxamethonium by intravenous infusion (2 mg/ml in physiological saline) after the initial dose at induction. Groups I and II were ventilated using a Barnet Mk III ventilator, time-cycled as a minute volume divider. The tidal volume was calculated according to the Radford nomogram (Radford, Ferris and Kriete, 1954) plus 25% of the calculated volume, measured as the expiratory tidal volume by the flowmeter on the ventilator. The pressure developed in the endotracheal tube was measured via a side-arm. The inspiratory/expiratory ratio was adjusted to give the best result obtainable for the individual patient, as judged by tracheal pressure and expiratory tidal volume, although the inspiratory phase was always long enough to give an end-inspiratory plateau for an approximate determination of the alveolar pressure. Halothane 1 % was given for 5 min and thereafter maintained at 0.5%. The administration was stopped in some patients when arterial hypotension failed to respond to intravenous fluid therapy with Ringer's lactate solution. For the catheter inflation ventilation nitrous oxide and oxygen from independent sources were used, each delivered to the "Oxymix" at a pressure in excess of 4 atm abs. Tidal volumes and intratracheal pressures were not measured. However, before using this method, trials were performed using a variety of models based on a large carboy to represent lung compliance (Mushin et al., 1969). After cannulation of the radial or brachial artery, samples for blood-gas measurement were taken before induction Further samples were taken after 10 min
Downloaded from http://bja.oxfordjournals.org/ at University of Chicago on July 5, 2015
Apparatus The apparatus for the direct catheter inflation ventilation (fig. 2) consisted of an "Oxymix" mixing chamber (Simonsen & Weel, Copenhagen) with its two inlets connected to sources of oxygen and nitrous oxide respectively. The "Oxymix" permitted the oxygen: nitrous oxide ratio to be varied. The outlet of the mixing chamber was connected to an adjustable pressure reduction valve (Teknova Mini Regulator 236 A) for control of the injection pressure. From this was taken a suitable length of tubing with a pistol-type on/off valve at the distal end. This valve was fitted with a Luer lock on the outlet to match the Luer fitting of the inflation tube.
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ANAESTHESIA FOR FIBREOPTIC BRONCHOSCOPY TABLE I. Measured indices in male patients of groups I, II and III (range of values in parentheses)
Age(yr) Duration of anaesthesia (min) Duration of bronchoscopy (min) Mean arterial pressure (mm Hg) Pre-induction Post-intubation Least during bronchoscopy Tidal volume (ml) Change in alveolar pressure (cm H2O) Paco,
Start of bronchoscopy
Paco,
During bronchoscopy Lowest value
Paco,
Highest value
Pa
co, Pa0>
Group II (5 patients)
Group III (6 patients)
57 (40-68) 50 (36-65) 23 (16-38)
63 (53-73) 34 (28-47)
65 (54-74) 40 (28-65) 31 (21-47)
23 (20-25)
118 (80-155) 110 (70-145) 86 (50-110) 526 (400-650) + 3 (0 to +9)
101 (90-110) 103 (90-120) 136 (85-150) 128(120-140) 84 (55-110) 103 (95-120) 560 (450-650) + 3 ( + l to +6)
38 80 37 137
(31-45) (65-92) (31-48) (75-250)
40 (35-43) 67 (52-75) 38 (31-46) 137 (115-155)
39 (34-45) 82 (66-90) 40 (23-54) 162 (106-240)
39 116 46 134
(31-50) (83-210) (31-54) (83-235)
31 (26-35) 87 (76-98) 35 (29-41) 125 (100-204)
32 (19-39) 163 (71-240) 36 (29-43) 234 (138-330)
ventilation by the Barnet ventilator for methods I and II, or immediately after the passing of the fibreoptic bronchoscope in method III, and thereafter at 5-min intervals until the bronchoscopy was completed. All patients were observed in the recovery room for at least 1 hr, a final blood-gas sample being taken before return to the ward. The duration of anaesthesia was taken as from the time of induction until the patient could respond adequately to the command to lift the head from the pillow. The ratio of oxygen to nitrous oxide was 1 : 2, but in two patients this was changed to 1 : 1, and in one to 2 : 1 , where the patients (all female group I) appeared to be cyanosed. The bronchoscopic examination had to be interrupted temporarily for two of these patients. RESULTS
In tables I and II the sexes are separated, and divided into male groups I, II and III, corresponding to methods I, II and III, and female groups I and III. Method II was not used for the female patients. Male patients In most respects, the results for groups I and II are comparable.
TABLE II. Measured indices in female patients of groups I and HI (range of values in parentheses)
Age (yr) Duration of anaesthesia (min) Duration of bronchoscopy (min) Mean arterial pressure (mmHg) Pre-induction Post-intubation Least during bronchoscopy Tidal volume (ml) Change in alveolar pressure (cm
Group I (11 patients)
Group III (5 patients)
66.7 (55-81) 52 (43-67)
57 (42-66) 40 (35-58)
19 (11-31)
26 (22-30)
125 (85-190) 115 (75-180) 84 (60-135)
103 (80-140) 121 (100-140) 105 (85-150)
450 (370-550) + 10 ( + 2 to +14)
Blood-gases (mm Hg) 38 (33-43) Pre-induction , 38 (36-^3) 72 (59-86) 84 (75-95) Pao, Start of bronchoscopy 38 (29-51) Paco, 38 (31-47) Pao, 124 (57-195) 112 (75-158) During bronchoscopy 29 (22-33) Lowest value Paco, 42 (32-56) 98 (53-168) 118 (90-176) Pao, Highest value PaCo, 48 (39-76) 34 (28-39) Pa,0, 128 (85-230) 189 (100-210)
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Blood-gases (mm Hg) Pre-induction
Group I (12 patients)
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Females
Group I females showed poorer results than in the males, with increased alveolar pressure, circulatory depression and several unsatisfactory blood-gas values. In group III females satisfactory blood-gas tensions were obtained, there was no arterial hypotension, and the fibreoptic procedures were completed without hindrance. DISCUSSION
As the difference between groups I and II is really only that of the material from which the endotracheal tube is made, it is not surprising that the results in these groups are similar. However in group II, after an initial increase in Pa Oj during 10 min of normal ventilation, there occurred a curious tendency for the Pa o , to decrease following the start of the bronchoscopy, and this was progressive in four of the five patients. Because of the risk of laryngeal trauma it was considered undesirable to use endotracheal tubes larger than 8 mm i.d. in the female patients (Dam and Zwergius, 1952). The tracheoscope, which also has the disadvantage of being rigid, was not used in the female patients on account of its size (12 mm o.d.), and because of the decrease in oxygen tension found in the male group II patients. Although the results were satisfactory for some of the female patients in group I, it can be seen that the increased alveolar pressure was accompanied by arterial hypotension similar to that found in the male patients. The blood-gas values were unsatisfactory, with increases in Pa COj , and decreases in Pa Oj to hypoxic values in three patients who had large pulmonary lesions.
The female group III patients all had satisfactory blood-gas tensions without circulatory depression. Satisfactory results were achieved with the three methods in the male patients. Method I was not satisfactory for the female patients. The reduction of cross-sectional area caused by the solid fibreoptic bronchoscope passing through a conventional tube in the male may be up to 25%. In the female it is nearer 45%, which, because of the curvature of the tube and especially in conjunction with reduced pulmonary function, may lead to inadequate ventilation. However, the use of catheter inflation ventilation appears to offer a better alternative. It is relatively easy to hyperventilate the patients, as can be seen from the decrease in Pa COj during bronchoscopy. However, certain precautions should be taken. Under testing, it was found that the length of the injection period was a decisive factor in determining the amount of the increase in intrathoracic pressure. Thus the duration of the inspiratory phase must be kept short (less than 1 sec). There must be no increase in resistance to expiration, for example as a result of laryngeal spasm round the tube since, when the bronchoscope is inserted through the larger bore tubes it is essential for at least part of the expiratory gases to pass via the outside of the tube. Vigilance is required to prevent returning laryngeal muscle tone from closing the glottis. This can be detected by an alteration in the quality of the sound of the expiratory phase and it may also become noisier. A hand resting lightly on the abdomen may feel a slight rebound immediately after the inspiratory phase is over. This would indicate that an increase in the rate of the suxamethonium infusion is required. Our surgical colleagues preferred the catheter inflation ventilation as, in their opinion, it gave better dilatation of the bronchial tree, especially in the female patients. ACKNOWLEDGEMENTS
Simonsen and Weel, Copenhagen (British address: Simonsen & Weel Ltd, Hatherley House, Hatherley Road, Sidcup, Kent) loaned the "Oxymix" mixing chamber, reduction valve and pistol-type release valve. Mrs Ellen Kaufman and Miss Doris Hansen measured blood-gas tensions. Thanks are also given to surgical colleagues of the Department of Thoracic Surgery and the anaesthetic nurses of Bispebjerg Hospital, Copenhagen. Dr W. H. Dam, consultant in charge, Department of Anaesthesia, gave helpful criticism and advice. REFERENCES
Borgeskov, S., Becker, J., and Pedersen, A. B. (1973). The flexible broncho-fiberscope. Endoscopy, 5, 177. Carden, E., and Crutchfield, W. (1973). Anaesthesia for microsurgery of the larynx. Can. Anaesth. Soc.J., 20, 378.
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The rather longer recovery for group I was probably a result of the continuation of halothane administration until the examination was complete, while the end-point of the bronchoscopy was better estimated in group II. Group III patients showed a quicker recovery, as might be expected. The arterial pressure decreased during anaesthesia in both groups I and II. There was no decrease in arterial pressure in the group III patients. Although the blood-gas tensions revealed no serious abnormalities in groups I and II, higher PaOi tensions were measured in the group III patients. There was a decrease in Pa COi in all the group III patients during bronchoscopy.
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ANAESTHESIA FOR FIBREOPTIC BRONCHOSCOPY
ANESTHESIE POUR BRONCHOSCOPIE FIBREOPTIQUE RESUME
La bronchoscopie fibreoptique est une aide utile pour la formulation des diagnostics, mais elle peut entrainer
certaines difficultes lorsqu'on l'associe a l'anesthesie endotracheale. De ce fait, une ventilation adequate des malades peut-etre difficile lorsque ceux-ci souffrent d'une mauvaise fonction pulmonaire et en particulier chez les femmes en raison des petites dimensions des ouvertures de leur larynx. Dans les essais que Ton a effectues sur trois methodes d'anesthesie endotracheale, sur 39 malades, la technique directe de dilatation du catheter a assure une ventilation satisfaisante sans aucune depression circulatoire. ANASTHESIE FUR FASERNOPTIKBRONCHOSKOPIE ZUSAMMENFASSUNG
Fasernoptik-Bronchoskopie ist eine nutzliche Diagnosehilfe, kann aber zu Schwierigkeiten fuhren, wenn sie mit endotrachealer Anasthesie verwendet wird. Daher kann eine ausreichende Beluftung bei Patienten mit verminderter Lungenfunktion schwierig sein, besonders bei weiblichen Patienten, aufgrund der geringeren Grosse ihrer Kehlkopfoffnungen. Bei einem Versuch mit drei Methoden endotrachealer Anasthesie bei 39 Patienten ergab eine direkte Katheter-Fullungsmethode eine zufriedenstellende Beluftung ohne Kreislaufhemmung. ANESTESIA POR BRONCOSCOPIA FIBRAOPTICA SUMARIO
La broncoscopia fibraoptica es una ayuda diagnostica util, pero puede producir dificultades cuando se relaciona con la anestesia endotraqueal. En consecuencia puede ser dificiluna ventilacion adecuada en pacientes con una funcion pulmonar deteriorada y, en especial, en pacientes femeninos a causa del tamano menor de la apertura de sus laringes. En un experimento de los tres metodos de anestesia endotraqueal en una serie de 39 pacientes, la tecnica de insuflacion directa del cateter produjo una ventilacion satisfactoria con depresion circulatoria.
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Dam, W.j and Zwergius, E. (1952). Laryngeale komplikationer efter langvarig endotracheal intubation af narkotisk forgiftede patienter. Nord. Med., 48, 1095. Editorial (1974). Safety and fibreoptic bronchoscopy. Br. Med. J., 3, 542. Grant, I. W. B. (1974). Safety and fibreoptic bronchoscopy. Br. Med. J., 4, 464. Ikeda, S. (1970). Flexible bronchofiberscope, presented at the meeting of the American Broncho-esophagological Association, Florida, 20-21 April. Noboru, Y., and Scichiro, I. (1968). Flexible bronchonberscopcKeioJ1. Med., 17, 1. Mushin, W. W., Rendell-Baker, L., Thompson, P. W., and Mapleson, W. W. (1969). Automatic Ventilation of the Lung, 2nd edn., p. 179. Oxford and Edinburgh: Blackwell. Radford, E. P., jr, Ferris, B. G., jr, and Kriete, B. C. (1954). Clinical use of a nomogram to estimate proper ventilation during artificial respiration. JV. Engl. J. Med., 251, 877. Sanders, R. D. (1967). Two ventilating attachments for bronchoscopes. Del. Med.J., 39, 170. Spoerel, W. E. (1969). Ventilation through an open bronchoscope. Can. Anaesth. Soc.J., 16, 61. Greenway, R. E. (1973). Technique of ventilation during endolaryngeal surgery under general anaesthesia. Can. Anaesth. Soc. J., 20, 369. Narayanan, P. S., and Singh, N. P. (1971). Transtracheal ventilation. Br. J. Anaesth., 43, 932. Tahir, A. H. (1972). General anesthesia for bronchofiberscopy. Anesthesiology, 37, 564. Wanner, A., Amikam, B., and Sackner, M. A. (1972). A technique for bedside bronchofiberscopy. Chest, 61, 287.
