Brit. J. Anaesth. (1973), 45, 912
THE TORONTO VENTILATING LARYNGOSCOPE S. GALLOON SUMMARY
A new use is described for the Sanders ventilating-venturi principle. A long 16-gauge needle is clipped on to the standard curved (Macintosh) blade of a laryngoscope, thus allowing continuous ventilation while intubating an apnoeic patient. Ventilation can be maintained as long as required, and no time limit need be set to the intubation. The needle and clip fits any standard curved laryngoscope blade, and comes off easily for cleaning. on the proximal end. Just distal to this a clip (3) is soldered to the needle; this clip fixes the needle firmly to the curved (Macintosh) blade of the standard laryngoscope (figs. 2 and 3). The distal end of the needle is bent in two directions (4, 5) to mould it to the shape of the blade. This end is also covered with a short length of plastic tubing (6) to protect the mucosa of the mouth and throat. METHOD OF USE
The Bird Mark II ventilator is turned on just before inducing anaesthesia, with the three-way tap turned to atmosphere. The laryngoscope is introduced as usual, care being taken not to damage the mucosa by the end of the needle which stands away from the end of the laryngoscope blade (fig. 2). As soon as the epiglottis is identified and lifted by the tip S. GALLOON, M.B.,CH.B., D.A., F.F.A.R.C.S.(LOND.), Depart-
ment of Anaesthesia, University of Toronto and Toronto General Hospital, 101 College Street, Toronto, Ontario, Canada.
FIG. 1. The needle and clip used for the ventilating laryngoscope.
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In 1967 Sanders described a simple but elegant way of ventilating patients anaesthetized for bronchoscopy. This uses the venturi principle and allows the anaesthetist to ventilate a completely apnoeic patient for long periods without interrupting the bronchoscopy. This method has been modified and refined since then (Spoerel, 1969; Carden, Trapp and Oulton, 1970; Spoerel and Grant, 1971), but still represents one of the most significant advances in anaesthesia in the last 10 years. Other modifications have described the use of the Sanders oxygen injector for micro-laryngeal surgery, adapting the long straight blade used for biopsy or for photography (Albert, 1971; Lee, 1972). The method described here allows the venturi principle to be used for ventilating patients during ordinary intubation and also particularly for teaching intubation and for photography of the larynx and vocal cords. A Bird Mark II ventilator is attached to a three-way tap (1) and a 6-inch long 16-gauge needle (fig. 1), which has a Luer-Lok attachment (2)
913
THE TORONTO VENTILATING LARYNGOSCOPE
of the blade, the three-way tap is turned so that the oxygen from the Bird Mark II ventilator flows through the needle and into the larynx, thus ventilating the patient. The position of the end of the needle relative to the epiglottis and the larynx is fairly critical, and small changes of the angle of the needle at 4 may be necessary to get the correct position.
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FIG. 3. The needle attached to the laryngoscope blade, showing the moulding to the shape of the blade.
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FIG. 4. Recording of ventilation of patient during the use of the ventilating laryngoscope.
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FIG. 2. The needle attached to the laryngoscope blade, showing the moulding to the shape of the blade.
914
BRITISH JOURNAL OF ANAESTHESIA EXPIRATION TIDAL VOLUME INSPIRATION
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FIG. 5. Recording of ventilation of patient during the use of the ventilating laryngoscope. MEASUREMENT OF VENTILATION
In 10 patients the ventilation before, during and after the use of the ventilating laryngoscope was recorded by using a Pneumobelt.* Figures 4 and 5 show the movement of the chest obtained in 2 patients, representative of the recordings obtained in all 10 patients. These figures also show how the tidal volumes obtained with the ventilating laryngoscope were measured. As soon as the patient was intubated, he was attached to a mechanical ventilator and ventilated at three different tidal volumes. The tidal volumes were measured with a Wright Respirometer, previously calibrated with a dry-gas meter, and these volumes were related to the recordings with the Pneumobelt. ACKNOWLEDGEMENTS
I would like to thank Dr R. A. Gordon, Chairman of the Department of Anaesthesia, for his constant support •Electronics for Medicine, 30 Virginia Road, White Plains, New York 10603.
and help, and Dr I. Smith, University of Aberdeen, for his stimulating comments and criticism. Thanks also to Dr K. W. Taylor and his Department of Medical Engineering and Bio-physics for construction of the clip, and the Department of Medical Photography, Toronto General Hospital, for figures 1-3. REFERENCES
Albert, S. N. (1971). The Albert-Sanders adaptor for ventilating anaesthetized patients for micro-laryngeal surgery. Brit. J. Anaesth., 43, 1098. Carden, E., Trapp, W. G., and Oulton, J. (1970). A new and simple method for ventilating patients undergoing bronchoscopy. Anesthesiology, 33, 454. Lee, S. T. (1972). A ventilating laryngoscope for inhalation anaesthesia and augmented ventilation during laryngoscopic procedures. Brit. J. Anaesth., 44, 874. Sanders, R. D. (1967). Two ventilating attachments for bronchoscopes. Delaware med. J., 39, 170. Spoerel, W. E. (1969). Ventilation through an open bronchoscope (preliminary report). Canad. Anaesth. Soc. J., 16, 61. Grant, P. A. (1971). Ventilation during bronchoscopy. Canad. Anaesth. Soc. J., 18, 178.
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VENTILATING LARYNGOSCOPE