Anaesthesia, 2001, 56, pages 441±446 ................................................................................................................................................................................................................................................

C A S E R E P O RT

Airway ®re due to diathermy during tracheostomy in an intensive care patient S. A. Rogers,1* K. G. Mills2 and Z. Tufail3 1 Specialist Registrar, 2 Consultant, Department of Anaesthesia and Intensive Care, and 3 Specialist Registrar, Department of Cardiothoracic Surgery, The Cardiothoracic Centre, Liverpool, UK Summary

We describe a case of airway ®re in an 83-year-old, critically ill patient. The ®re occurred during a surgical tracheostomy under general anaesthesia, following ignition of the tracheal tube by diathermy. After debridement of the burnt tissue and treatment with intravenous antibiotics and glucocorticoids, the patient's respiratory function worsened initially. The patient eventually recovered without long-term sequelae and was discharged from the intensive care unit. The circumstances of this and other similar incidents are reviewed, as are the suggested methods for preventing this frightening occurrence. Keywords Airway ®re: tracheostomy; diathermy. ...................................................................................... Correspondence to: Dr S. A. Rogers * Present address: Department of Anaesthesia and Intensive Care, University Hospital Aintree, Lower Lane, Liverpool L9 7AL, UK. Accepted: 2 November 1999

Fires in the operating theatre are seen as mostly of historical interest, dating back to the era of ether and cyclopropane anaesthesia. Recent interest in airway ®res has mostly centred on the use of lasers in laryngeal surgery. However, ®res caused by diathermy ignition of tracheal tubes are still occasionally reported and may well be underreported. These incidents have led to both morbidity and mortality; therefore, anaesthetic and surgical techniques should be modi®ed to reduce their incidence and severity. Case history

An 83-year-old, male intensive care patient was listed for a surgical tracheostomy. He had undergone coronary artery bypass grafting of four vessels 7 days previously, and had remained intubated (with an 8.5-mm internal diameter Mallinckrodt PVC oral tracheal tube) and ventilated because of respiratory failure and a stroke. He required 70% oxygen with 2.5 cmH2O positive endexpiratory pressure (PEEP), as well as epinephrine and dopamine infusions. He had also developed acute renal failure requiring haemo®ltration. Q 2001 Blackwell Science Ltd

On the afternoon of the operation, he was transferred from the intensive care unit (ICU) to the main operating theatre. The patient was ventilated with iso¯urane in 100% oxygen using the circle system of a Drager Cato anaesthetic machine (Drager Medizintechnik GmbH, Lubeck, Germany), and was monitored with electrocardiogram, pulse oximeter, invasive arterial blood pressure, end tidal carbon dioxide and anaesthetic gas concentrations. The surgeon performed a standard collar incision and dissected down to the trachea with scissors, securing haemostasis with coagulating bipolar diathermy. The isthmus of the thyroid did not require division. The surgeon informed the anaesthetist that he would open the trachea using the diathermy, and the anaesthetist partially withdrew the tracheal tube. As the trachea was opened with the diathermy in coagulation mode, there was a loud noise and ¯ames rushed out of the tracheal stoma during the inspiratory phase of ventilation. The circuit was immediately disconnected from the tracheal tube and the ®re was rapidly extinguished with saline. The tracheal tube was removed and an 8-mm Portex tracheostomy tube was inserted into the trachea without dif®culty. The patient did 441

Case reports Anaesthesia, 2001, 56, 441±446 ................................................................................................................................................................................................................................................

not become hypoxaemic or suffer any systemic disturbance. A small area of burnt subcutaneous tissue around the stoma was debrided. No muscle or deeper burn could be seen. Examination of the tracheal tube showed that it had been ignited and extensively burnt (Fig. 1) around the cuff. Although it was quite deformed, it had remained patent. A bronchoscopy via the new tracheostomy was performed. A possible small area of super®cial burn was observed on the posterio-lateral surface of the trachea, but no other burns or signs of inhalational injury were seen. On direct laryngoscopy, no oral or laryngeal burns were seen. After consultation with a senior thoracic surgeon, dexamethasone 4 mg was given intravenously. The operation was completed without further problems and the patient was transferred back to the ICU. Over the next 48 h, his oxygen requirement increased to 100%. He required neuromuscular blocking agents to facilitate ventilation and he developed copious secretions from his lungs. After discussion, no further doses of dexamethasone were given. A further bronchoscopy showed normal trachea and bronchi and no signi®cant thermal injury.

Figure 1 The 8.5-mm internal diameter Mallinckrodt PVC oral tracheal tube that was ignited at the cuff and extensively burnt. 442

After the ®rst 48 h, the patient's condition improved and he was discharged from the ICU to a general ward 26 days later with the tracheostomy tube in place. The patient was uneventfully decannulated a few days later and was transferred to his local hospital for further care 14 days after his discharge from the ICU. He eventually took his own discharge 100 days after the airway ®re. At a follow-up cardiac surgery clinic 2 weeks later he was in good health. Discussion

Surgical tracheostomy is a commonly performed operation that is undertaken by a number of surgical specialties [1]. It is also frequently required in critically ill patients. Although large retrospective studies suggest that the morbidity and mortality of the operation have been decreasing for some years [1], there are still many short- and longterm complications. Ignition of the tracheal tube by diathermy (or electrocautery, electrosurgery) during surgical tracheostomy is reported occasionally [2±7]. Its incidence is impossible to determine [8], but, even though it is rare, laryngotracheal burns following such a ®re may have contributed to a fatality [5]. The classical triad needed for a ®re or explosion (fuel, energy and oxidising sources) are all present during surgical tracheostomy. Possible fuel sources include the tracheal tube (usually made of PVC), charred tissue, suture material, drapes and antiseptic alcohol solutions [2, 4, 9, 10]. Diathermy delivers an energy source that generates tip temperatures in excess of 910 8C (1500 8F) [9] using an alternating sine wave current at frequencies between 20 000 and 50 000 Hz. The cutting mode is continuous, whereas coagulation is intermittent [4, 5, 11]. The oxidising sources are both oxygen and nitrous oxide; the latter being a powerful oxidising agent in its own right [12]. In many of the reported cases, there are several common factors. Many occurred in intensive care patients [2±7] with complex needs, such as high oxygen requirements and poor tolerance of periods of apnoea and loss of PEEP. These patients have an increased incidence of mortality and morbidity in larger studies of surgical tracheostomy [1, 13]. High oxygen requirements [3, 5, 6], routine preoxygenation prior to changing the tracheal tubes [2, 4, 7] and supplementary nitrous oxide [9] were the usual oxidising sources. In several cases [4, 6, 7], including the one reported here and the case that resulted in a fatality [5], the tracheal incision was intentionally made using the diathermy, either in the cutting or coagulation mode. However, in other cases [2, 3], the tracheal incision was made with a scalpel and the tracheal tube was ignited by the diathermy while securing haemostasis. In most of the cases [2±7], ignition was started by cuff de¯ation causing a Q 2001 Blackwell Science Ltd

Anaesthesia, 2001, 56, 441±446 Case reports ................................................................................................................................................................................................................................................

high ¯ow leak of oxygen-enriched gas into the surgical ®eld, or in the case of oral ®res, a retrograde leak of oxygen into the oral and pharyngeal cavities. In the case reported here, failure to withdraw the tracheal tube suf®ciently and opening the trachea with the diathermy were probably the most important factors. Previous authors have made various recommendations regarding the prevention of such ®res, which can be grouped into anaesthetic and surgical considerations. Anaesthetic considerations include keeping the inspired oxygen concentration just high enough to allow satisfactory arterial oxygen saturation, which may be dif®cult in intensive care patients. However, some authors still recommend the routine use of high oxygen concentrations [2]. Combining oxygen with a non-¯ammable carrier gas, such as nitrogen or helium, has also been recommended [2, 3]. Other manoeuvres include: positioning the tracheal cuff either just above the carina or above the operative site, ®lling the tracheal cuff with saline and packing uncuffed tracheal tubes. Controversy also exists as to which type of tracheal tube material is best, with PVC being described as both suitable [2] and unsuitable [3]. The newer generation of laser-resistant tubes may be the best solution [8], but this would entail an additional tube change in critically ill patients. Surgical considerations include: opening the trachea with a scalpel blade, using a suction catheter to remove oxygen and smoke from the operative ®eld, and fashioning the tracheostomy in stages if there is a large gas leak. Use of ¯ame-retardant drapes, swabs and sutures may also be helpful, but these are often either expensive or unavailable. The most important factor is preventing the diathermy from coming into contact with both a fuel and an oxidising source. This is best achieved by avoiding diathermy altogether. If diathermy is required, recommendations include disconnecting the breathing circuit prior to diathermy use, covering visible portions of the tracheal tube with saline-soaked pledglets and using bipolar diathermy in the coagulation mode at the lowest effective power level. The bipolar mode will minimise current leakage to the surrounding tissues. Practice ®re drills may be of bene®t [4, 9], but the most important point is that the surgeon and the anaesthetist must work together via good communication. In the event of a ®re, it is important to assess the entire airway with both bronchoscopy and laryngoscopy. Treatment of airway ®res involves antibiotics, dexamethasone and regular

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assessment of respiratory function on the ICU [4, 7]. However, diathermy use can be avoided completely by percutaneous dilational tracheostomy, a technique with a favourable complication rate [14]. References 1 Zeitouni AG, Kost KM. Tracheostomy: a retrospective review of 281 cases. Journal of Otolaryngology 1994; 23: 61±6. 2 Lim HJ, Miller GM, Rainbird A. Airway ®re during elective tracheostomy. Anaesthesia and Intensive Care 1997; 25: 150±2. 3 Bailey MK, Bromley HR, Allison JG, Conroy JM, Krzyzaniak W. Electrocautery-induced airway ®re during tracheostomy. Anesthesia and Analgesia 1990; 71: 702±4. 4 Aly A, McIlwain M, Duncavage J. Electrosurgery-induced endotracheal tube ignition during tracheotomy. Annals of Otology, Rhinology and Laryngology 1991; 100: 31±3. 5 Lew EO, Mittleman RE, Murray D. Endotracheal tube ignition by electrocautery during tracheostomy: case report with autopsy ®ndings. Journal of Forensic Science 1991; 36: 1586±91. 6 Marsh B, Riley RH. Double-lumen tube ®re during tracheostomy. Anesthesiology 1992; 76: 480±1. 7 Le Clair J, Gartner S, Halma G. Endotracheal cuff ignited by electrocautery during tracheostomy. Journal of the American Association of Nurse Anesthetists 1990; 58: 259±61. 8 Sosis MB, Braverman B. Prevention of cautery-induced airway ®res with special endotracheal tubes. Anesthesia and Analgesia 1993; 77: 846±7. 9 Thompson JW, Colin W, Snowden T, Hengesteg A, Stocks RMS, Watson SP. Fire in the operating room during tracheostomy. Southern Medical Journal 1998; 91: 243±7. 10 Brechtelsbauer PB, Carrol WR, Baker S. Intraoperative ®re with electrocautery. Otolaryngology ± Head and Neck Surgery 1996; 114: 328±31. 11 Hazard Report. Electrosurgical airway ®res still a hot topic. Health Devices 1996; 25: 260±2. 12 Macdonald AG. A short history of ®res and explosions caused by anaesthetic agents. British Journal of Anaesthesia 1994; 72: 710±22. 13 Wease GL, Frikker M, Villalba M, Glover J. Bedside tracheostomy in the intensive care unit. Archives of Surgery 1996; 131: 552±5. 14 Hill BB, Zweng TN, Maley RH, Charash WE, Toursarkissian B, Kearney PA. Percutaneous dilatational tracheostomy: report of 356 cases. The Journal of Trauma: Injury, Infection, and Critical Care 1996; 40: 238±43.

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