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matized patient is extremely difficult, even with adequate sedation, topical anaesthesia, and patient cooperation. Although fibreoptic intubation may be associated with a "high rate of success" and "a low rate of complications," these statements apply primarily to elective or semielective cases in experienced hands. The patient with a known or suspected unstable cervical spine injury is likely to have other injuries that may interfere with safe and rapid fibreoptic intubation, such as a concomitant intracranial mass or hypertension, and upper airway blood, vomitus, or anatomical disruption. We are unaware of data to support the safety and rapidity of fibreoptic intubation in these patients. Furthermore, relatively few practicing anaesthestists perform fibreoptic intubation with enough frequency to maintain the facility demanded in these cases. Although the authors' did suggest that "... anaesthetists should intubate the patients in the manner with which they have the most expertise," we feel fibreoptic intubation should be reserved for non-emergency patients. Another option for airway management not mentioned by the authors is percutaneous transtracheal ventilation (PTV). This technique can be easily performed, even with minimal practice, and will provide adequate minute ventilation to maintain normo- or hypocarbia with excellent oxygenation in apnoeic adults.~--~ Although often thought a temporizing measure, PTV has been used to ventilate apnoeic adults for up to 75 min. 3 The equipment to perform PTV is readily available in the emergency department, intensive care unit, and operating room. A recent review by Benumof outlined the technique, materials, and contraindications for PTV. 4 As with all methods of airway management with an unstable cervical spine injury, there are few prospective data to support the safety of this technique. However, no chin or neck manipulation is necessary during PTV, so that little harm would be expected. When properly performed, PTV may provide protection from aspiration in the supine patient. 5-6 If desired, an elective fibreoptic intubation (using the transtracheal cannula as a landmark), cricothyroidotomy or tracheostomy can be performed in patients unable to have an oral or nasal tracheal tube placed safely under direct laryngoscopy. We congratulate the authors on tackling a broad and controversial topic. As with many medical dilemmas, there is no single right answer or approach. We hope that our comments will aid the physician should an airway crisis occur in a patient with a suspected unstable cervical spine injury.

CANADIAN J O U R N A L OF A N A E S T H E S I A

Donald M. Yealy MO Kimberly K. Cantees MD John P. McGuinness Mr) The Departments of Anesthesiology and Emergency Medicine, Darnall Army Community Hospital, Fort Hood, Texas, USA 76544 REFERENCES

I JacobsHB. Emergency percutaneous transtracheal catheter

and ventilator. J Trauma 1972; 12: 50-5. 2 Jacobs HB, Smyth NPD, Witorsch P. Transtracheal

3 4

5

6

catheter ventilation: clinical experience in 36 patients. Chest 1974; 65: 36-40. Spoerel WE, Narayanan PS, Singh NP. Transtracheal ventilation. Br J Anaesth 1971; 43: 932-9. BenumofJL, Scheller MS. The importance of transtracheal jet ventilation in the management of the difficult airway. Anesthesiology 1989; 7 I: 769-78. Yealy DM, Plewa MC, Reed JJ et al. Aspiration during manual low frequency jet ventilation. Ann Emerg Med 1989; 18: 458-9. Klain M, Keszlar H, Stool S. Transtracheal high frequency jet ventilation prevents aspiration. Crit Care Med 1983; 170-2.

REPLY We thank Yealy et al .for their interest in our review and would like to address their criticisms and comments. We did not "conclude that based on available data" that the optimum mode of intubation in an acutely traumatized patient with an unstable spine is an awake, flbreoptic bronchoscope-aided (FOB) intubation. The words in quotation marks are those of Yealy et at. and these remarks should not be attributed to us. We did express the opinion that, in a non-urgent situation and given that the anaesthetist is both familiar and comfortable with the technique of FOB intubation, the technique had some advantages when compared with other modes of intubation. We then outlined what we perceived those advantages to be. We did note that there is no evidence that neurological outcome is influenced by the mode of intubation, in this patient population, in the acutely traumatized patient requiring urgent airway intervention, we emphasized that intubation must proceed with both haste and care. We did not specify a particular technique but did comment, again, that there were no data to recommend one technique over another, in preserving neurological function. We did suggest, as Yealy notes, that anaesthetists should care for these patients in the manner with which they have the most expertise and the greatest comfort. In the situation described, of a known or suspected unstable cervical spinal injury with concomitant mass or hypertension, upper airway blood or vomitus and anatomical disruption, we would regard percutaneous transtracheal ventilation (PTV) with high-frequency jet ventilation (HFJV) as a temporizing intervention only. While we recognize that adequate ventilation

CORRESPONDENCE and oxygenation may be obtained with PTV and HFJV, we have some reservations about this technique in these patients. Access to the neck is often obstructed by various devices serving to stabilize the neck, rendering the placement of the transtracheal catheter problematic. These patients are often moved in the process of evaluation, as from stretcher to CT table, jeopardizing what may be already a tenuous airway. Finally, there is little evidence that the airway is adequately protected from soiling or aspiration in a patient population that is at significant risk for this event. Yealy cites two animal experimental models that suggest the risk of aspiration during PTV is low. However, in Yealy's own work, 66 per cent of dogs, at 45 ~of elevation, being ventilated with PTV and HFJV, suffered some degree of aspiration. There was no evidence of aspiration in animals intubated with a cuffed tracheal tube, under the same conditions. In the above situation, we are of the opinion that the priority is a secure and protected airway and that PTV with HFJV may be employed to ensure adequate ventilation and oxygenation while a plan is being formulated to secure the airway with a cuffed tube. Airway management of patients with known or suspected cervical spinal injury or instability should be dictated by common sense and care and not by a dogmatic approach and reliance on any particular algorithm. This statement is supported by both the critical care literature and the accumulated clinical experience in the management of these patients, in many centres, with a variety of techniques.

E. Crosby MD FRCr'C A. Lui MD ~CPC Ottawa Civic Hospital University of Ottawa

Fatal embolism To the Editor: In his editorial, "Fatal Embolism, ''~ Dr. Matthews correctly indicates the need for "compulsory national reporting of (anaesthetic-related) mortality and serious morbidity." He suggests that this may be a role for the Department of Health and Welfare. An alternative source of reporting of mortality, at least, are the provincial coroners and medical examiners. As they already review deaths, it would be logical to have them report to a central office. At the Annual Meeting of Chief Coroners and Medical Examiners (September, 1989, in Quebec City), we presented a systematic method for the investigation of anaesthetic-related deaths. Using such a common data base, information could be collected and collated. We suggested that, at a minimum, all intraoperative deaths become "notifiable," i.e., require mandatory reporting to the coroner/medical examiner. Better still would be a common period of 10-15 days postoperatively for notification of a death. However, the coroners and medical examiners operate under provin-

709 cial law, with twelve different acts, Currently, only three of the provinces/territories (Alberta, Manitoba, Prince Edward Island) require (by law) notification of operative deaths. Amendment of these acts to provide common times and conditions for reporting would be a major step towards helping us to know how many people die in Canada each year because of anaesthetic-related mishaps, the causes of these, and possible preventable factors. J.M. Davies, Msc MDFRO'C J.N. Armstrong MD Department of Anaesthesia Foothills Hospital at the University of Calgary REFERENCE I Matthews RL. Fatal air embolism. Can J Anaesth 1990;

37: 12-4.

Prevention of obstruction of epidural catheter by blood clot To the Editor: I read with interest the case report described by Cohen and Amar. I In the described case it was possible to dislodge a blood clot by reinserting a new stylet wire through the epidural catheter. A simple measure is described which can prevent blood clot formation when an epidural catheter enters a blood vessel and is positive for blood on aspiration. A 10-ml syringe filled with saline is attached to the epidural catheter and is flushed while the catheter is partially withdrawn. This process is repeated until blood aspiration test is negative. This simple measure of flush and partial withdrawal helps the epidural catheter to come out of the vessel. We have not encountered accidental intravenous injection of local anaesthetic and very rarely need to resite the catheter in patients when an epidural vessel has been punctured. Chandra M. Kumar FFARCS Department of Anaesthesia South Cleveland Hospital Middlesbrough Cleveland TS4 3BW REFERENCES I Cohen S, Amar D. A simple solution to blood clot ob-

struction of epidural catheter during labour. Can J Anaesth 1990; 37: 143-4.