518
P. MCGRATH
demonstrated by its widespread use in pain management units. 8 This case demonstrates an unusual situation since the patient's prone position with prolonged surgery underway precluded the commonly recommended methods for treating this type of injury. The use of guanethidine in this situation has not previously been reported but has a number of advantages. It is available in most hospitals providing chronic pain management services. Injecting guanethidine into an arterial cannula prior to removal is simple, gives immediate effect and no special skills are required. REFERENCES 1. Zideman OA, Morgan M. Inadvertent intra-arterial
injection of flucloxacillin. 36:296-298.
Anaesthesia 1981;
2. Knill RL, Evans O. Pathogenesis of gangrene following intra-arterial injection of drugs: A new hypothesis. Can Anaesth Soc J 1975; 22:637. 3. SlogoffS, Keats AS, Arlund C. On the safety of radial artery cannulation. Anesthesiology 1983; 59:42-47. 4. Evans JM, Latto lP, Ng WS. Accidental intraarterial injection of drugs: A hazard of arterial cannulation. Br J Anaesth 1974; 460-463. 5. King M, Milaszkiewicz R, Abbondati G, Carli F. Successful treatment of inadvertent intra-arterial injection of antibiotics. Anaesthesia 1986; 41 :969. 6. Vangerven M, Oelrue G, Brugman E, Cosaert P. A new therapeutic approach to accidental intra-arterial injection of thiopentone. Br J Anaesth 1989; 62:98-100. 7. Hurst LN, Evans HB, Brown OH. Vasospasm control by intra-arterial reserpine. Plast Reconstr Surg 1982; 70:595-599. 8. Cousins M, Bridenbaugh P. Neural Blockade. Lippincott, Philadelphia 1988; 494.
The Laryngeal Mask In the Management of a Paediatric Difficult Airway G. NATH* AND V. MAJORt Department of Anaesthesia. Christian Medical College Hospital. Vellore. India Key Words: AIRWAY: laryngeal mask, difficult intubation
The laryngeal mask airway (LMA), described in 1983 1-3 , is proving to be a very useful addition to the armamentarium of anaesthetists. Due to its ease of insertion without the need for laryngoscopy or muscle relaxants, it has been shown to be an effective means of managing the airway in cases of failed or difficult intubation. 4- 13 Here we describe its use in the anaesthetic management of a child with bums contractures. CASE HISTORY A five-year-old, 15.5-kg boy was admitted for release of extensive bums contractures over his neck and anterior chest wall. His neck was fixed in flex ion with his chin tethered to his anterior chest wall. Mouth opening was limited to 2 cm and was possible only by the movement of his whole head. His lower lip was everted and his mouth could not 'M.D. (Anaes.), Dip. N.B. (Anaes.), D.A., F.F.A.R.CS.L, Lecturer in Anaesthesia. tF.F.A.R.C.S., D.A., D.R.C.O.G., Professor and Head of Anaesthesia. Address for Correspondence/Reprints: Dr. G. Nath, Lecturer in Anaesthesi~ Department of Anaesthesia, Christian Medical College Hospital, VeUore, India 632 004. Accepted for publication April 22, 1992
be closed fully. He did not have stridor or other signs of airway obstruction though there was a history of noisy breathing. He was premedicated with trimeprazine 42 mg orally and hyoscine 0.2 mg IM one hour before the procedure. Monitoring was commenced with a cardioscope and a pulse oximeter. He was given an inhalationat induction with nitrous oxide, oxygen and halothane after which an intravenous line was inserted. As the level of anaesthesia deepened, it became increasingly difficult to maintain a patent airway. Two people were needed to maintain the airway, one solely for lifting the mandible forward. Laryngoscopy was attempted when he was deeply anaesthetised but it was impossible to see even the epiglottis. A size 2 LMA was inserted with no difficulty and the patient was maintained on spontaneous respiration till the end of surgery which lasted three hours. The neck contracture was released and skin grafting was carried out. The LMA was removed when he was awake, after oropharyngeal suction. The graft became infected and the patient needed further surgery two weeks later. On this occasion AnaestheslG and Intensn'e Care, Vol. 20, No. 4. NOI'ember, 1992
519
CASE REPORT
the neck, although held in flexion, could be extended by about twenty degrees more than before the first anaesthetic. This time we decided to attempt endotracheal intubation as the procedure was more extensive and necessitated repositioning during the course of the operation. From our previous experience we knew that intubation was likely to be difficult, and that it might be necessary to intubate over a bougie. While planning our anaesthetic technique, we found that the smallest available bougie could only pass through a 5.5 mm endotracheal tube, which was judged to be too big for our patient. Smaller endotracheal tubes were found to pass easily through a size 2 LMA when they were rotated so that their bevel faced backwards. Hence we decided to pass the endotracheal tube directly through the LMA. The patient was premedicated with atropine 0.15 mg and given an inhalational induction as before. When he was deep enough a size 2 LMA was inserted with ease. After again deepening the level of anaesthesia a Portex 5.0 mm uncuffed tube was inserted through the LMA, but it was not possible to push it beyond the end of the mask even with rotation of the tube. A 4.5 mm tube could be pushed through the LMA, but it only entered the trachea on the fourth attempt, after the head was extended as much as possible. Tube placement was confirmed by auscultation and the LMA was then removed. The subsequent course of the anaesthetic was uneventful, and the patient was extubated when awake. DISCUSSION
The role of the LMA in the management of the difficult airway is twofold. First, it can be inserted in order to obtain a patent airway. This has been done in adults4-8 as well as in the paediatric age groUp.9-12 Mason and Bingham9 demonstrate the safety of the LMA in a series of two hundred children including sixteen patients with difficult airways. There have also been reports of the use of the LMA in two patients with Pierre-Robin syndrome 10,1 I and in a six-year-old boy with arthrogryphosis mUltiplexa. 12 The LMA may also be used as an aid to intubation, and two techniques have been described. Brain l3 and McClune l4 suggested that the endotracheal tube may be passed directly through the LMA. In a recent study of one hundred adults undergoing elective surgery, intubation through the LMA with a 6.0 mm tube was successful in 90% of cases without cricoid pressure but in only 56% of cases when cricoid pressure was applied,15 Alternatively, a gum-elastic bougie can be inserted through the LMA and a suitable endotracheal tube can be threaded over it after removal of the mask. 16 This has been reported in Anaesthesia and Intensive Care. Vo/. 20. No. 4. November. 1992
two patients with difficult airways, both adults. 17 There are two problems in using the LMA to aid intubation in children. The mask is often too small to allow the passage of an appropriate sized endotracheal tube, especially when the LMA is in place. This happened in our patient. Also it is often difficult to obtain small enough bougies. Another problem is that even when the LMA is correctly placed, the oesophageal opening is often included within the cuff. This has actually been observed through the fibreoptic laryngoscope,18 and implies that a bougie or tube passed through the LMA can enter the oesophagus as easily as the trachea. In our patient, intubation was possible only on the fourth attempt, after extension of the head. We have not found any reports of the LMA having been used to aid intubation in children. In conclusion, the laryngeal mask airway is an effective aid in managing patients with difficult airways, in both adults and children. We report the anaesthetic management of a child with burns contractures and demonstrate the use of the LMA to aid intubation. REFERENCES
I. Brain AIJ. The Laryngeal Mask - a new concept in airway management. Br J Anaesth 1983; 55:801-805. 2. Brain AIJ, McGhee TD, McAteer El et al. The Laryngeal Mask airway. Development and trials of a new type of airway. Anaesthesia 1985; 40: 3 56-361. 3. Brain AIJ. Further developments of the Laryngeal Mask (letter). Anaesthesia 1989; 44:530. 4. Brain AIJ. Three cases of difficult intubation overcome by the Laryngeal Mask airway. Anaesthesia 1985; 40:353-355. 5. Thomson KD, Ordman AJ, Parkhouse N, Morgan BD. Use of the Laryngeal Mask airway in anticipation of difficult tracheal intubation. Br J PIast Surg 1989; 42:478-480. 6. Russell R, Judkins KC. The Laryngeal Mask airway and facial burns (letter). Anaesthesia 1990; 45:894. 7. Calder I, Ordman AJ, Jackowski A, Crockard HA. The Brain Laryngeal Mask airway. An alternative to emergency tracheal intubation. Anaesthesia 1990; 45:137-139. 8. AlIen JG, Flower EA. The Brain Laryngeal Mask. An alternative to difficult intubation. Br Dent J 1990; 168:202-204. 9. Mason DG, Bingham RM. The Laryngeal Mask airway in children. Anaesthesia 1990; 45:760-763. 10. Beveridge ME. Laryngeal Mask anaesthesia for repair of cleft palate. Anaesthesia 1989; 44:656-657. 11. Denny NM, Desilver KD, Webber PA. Laryngeal Mask airway for emergency tracheostomy in a neonate (letter). Anaesthesia 1990; 45:895. 12. Ravalia A, Goddard JM. The Laryngeal Mask and difficult tracheal intubation (letter). Anaesthesia 1990; 45: 168. 13. Brain AIJ. The Laryngeal Mask airway - a possible new solution to airway problems in the emergency situation. Arch Emerg Med 1984; 1:229-232.
520
G.
NATH AND
14. McC1une S, Regan M, Moore J. Laryngeal Mask airway for caesarean section. Anaesthesia 1990; 45:227-228. 15. Health ML, Allagian J. Intubation through the Laryngeal Mask. A technique for unexpected difficult intubation. Anaesthesia 1991; 46:545-548. 16. Allison A, McCrory J. Tracheal placement ofa gum elastic bougie using the Laryngeal Mask airway (letter). Anaesthesia 1990; 45:419-420.
V.
MAJOR
17. Chadd GO, Ackers JW, Bailey PM. Difficult intubation aided by the Laryngeal Mask airway (letter). Anaesthesia 1989; 44: 1015. 18. Payne J. The use of the Fibreoptic Laryngoscope to confirm the position of the Laryngeal Mask. Anaesthesia 1989; 44:865.
Prolonged Malignant Hyperthermia in the Absence of Triggering Agents N. POLLOCK,* M. HODGEst AND J. SENDALq
Department of Anaesthesia and Intensive Care. Palmerston North Hospital, Palmerston North, New Zealand Key Words: ANAESTHESIA; COMPLICATIONS: malignant hyperthermia, anaesthetic triggering agents, stress, creatine kinase, dantrolene
Episodes of malignant hyperthermia (MH) occurring in the recovery room or even later are well-documented. I. 3 Reports of MH developing in the absence oftriggering agents are few, particularly postoperatively,4,5 and in general these were mild reactions. A case is presented where a probable MH reaction developed in the absence of triggering agents, and continued several days into the postoperative period, requiring large doses of dantrolene for management. CASE REPORT An eighteen-year-old, 90 kg male presented for closed insertion of a Russel-Taylor rod into an unstable right tibial fracture, and excision of a loose talar fragment in the right ankle. Past anaesthetic and family history A diagnosis of malignant hyperthermia had been made at another hospital after an anaesthetic at the age of sixteen for drainage of nasal abscess. He had developed masseter spasm following the administration of thiopentone and suxamethonium, and this had intensified with the addition of isoflurane. Tracheal intubation was impossible and he was allowed to wake up. He was *F.F.A.R.A.CS., Specialist Anaesthetist. tF.F.A.R.A.CS., Director, Department of Anaesthesia and Intensive Care. tF.F.A.R.A.CS., Specialist Anaesthetist. Address for ConespondencelReprints: Dr. A. N. Pollock, cl· Palmerston North Hospital, Private Bag, Palmerston North, New Zealand. Accepted for publication April 22, 1992
admitted to intensive care unit (ICV), and responded to cooling measures only. Creatine kinase was measured at 59,160 IV (normal 20-215 IV), two days postoperatively. He had had no other previous general anaesthetic. In 1989 he received a regional block for suturing of fingers following a crush injury. During this procedure he developed tachycardia, hypertension and anxiety which was felt to be out of proportion to the stimulus received. The patient is a member of a large family susceptible to MH. His mother died suddenly at the end of an anaesthetic for appendicectomy at the age of twenty in 1973 (agents used included two 30 mg doses of suxamethonium and halothane), and a first cousin survived a fulminant episode of MH in 1987. Anaesthesia He was premedicated with midazolam 15 mg and metoclopramide 10 mg. Monitoring was established using an electrocardiogram, pulse oximetry, rectal temperature probe, radial arterial line and end-tidal C02 (ETC02)' Hourly urine outputs were recorded. Anaesthesia was induced at I 700 hours with thiopentone 400 mg and fentanyl 500 mcg and was maintained with 66% N 20 and incremental doses of fentanyl (2 mg total). The gases were administered through a vapour-free circle system reserved for MH patients. Muscle relaxation was provided with vecuronium 10 mg. The ventilator was set at 800 ml tidal volume and 8 breaths per minute (bpm) to maintain ETC0 2 at 36 Anal'~·th(,sJa
and Intenso'(' Care, f ·of. 20.
/\'0. 4,
Norember. 1992
P. MCGRATH
demonstrated by its widespread use in pain management units. 8 This case demonstrates an unusual situation since the patient's prone position with prolonged surgery underway precluded the commonly recommended methods for treating this type of injury. The use of guanethidine in this situation has not previously been reported but has a number of advantages. It is available in most hospitals providing chronic pain management services. Injecting guanethidine into an arterial cannula prior to removal is simple, gives immediate effect and no special skills are required. REFERENCES 1. Zideman OA, Morgan M. Inadvertent intra-arterial
injection of flucloxacillin. 36:296-298.
Anaesthesia 1981;
2. Knill RL, Evans O. Pathogenesis of gangrene following intra-arterial injection of drugs: A new hypothesis. Can Anaesth Soc J 1975; 22:637. 3. SlogoffS, Keats AS, Arlund C. On the safety of radial artery cannulation. Anesthesiology 1983; 59:42-47. 4. Evans JM, Latto lP, Ng WS. Accidental intraarterial injection of drugs: A hazard of arterial cannulation. Br J Anaesth 1974; 460-463. 5. King M, Milaszkiewicz R, Abbondati G, Carli F. Successful treatment of inadvertent intra-arterial injection of antibiotics. Anaesthesia 1986; 41 :969. 6. Vangerven M, Oelrue G, Brugman E, Cosaert P. A new therapeutic approach to accidental intra-arterial injection of thiopentone. Br J Anaesth 1989; 62:98-100. 7. Hurst LN, Evans HB, Brown OH. Vasospasm control by intra-arterial reserpine. Plast Reconstr Surg 1982; 70:595-599. 8. Cousins M, Bridenbaugh P. Neural Blockade. Lippincott, Philadelphia 1988; 494.
The Laryngeal Mask In the Management of a Paediatric Difficult Airway G. NATH* AND V. MAJORt Department of Anaesthesia. Christian Medical College Hospital. Vellore. India Key Words: AIRWAY: laryngeal mask, difficult intubation
The laryngeal mask airway (LMA), described in 1983 1-3 , is proving to be a very useful addition to the armamentarium of anaesthetists. Due to its ease of insertion without the need for laryngoscopy or muscle relaxants, it has been shown to be an effective means of managing the airway in cases of failed or difficult intubation. 4- 13 Here we describe its use in the anaesthetic management of a child with bums contractures. CASE HISTORY A five-year-old, 15.5-kg boy was admitted for release of extensive bums contractures over his neck and anterior chest wall. His neck was fixed in flex ion with his chin tethered to his anterior chest wall. Mouth opening was limited to 2 cm and was possible only by the movement of his whole head. His lower lip was everted and his mouth could not 'M.D. (Anaes.), Dip. N.B. (Anaes.), D.A., F.F.A.R.CS.L, Lecturer in Anaesthesia. tF.F.A.R.C.S., D.A., D.R.C.O.G., Professor and Head of Anaesthesia. Address for Correspondence/Reprints: Dr. G. Nath, Lecturer in Anaesthesi~ Department of Anaesthesia, Christian Medical College Hospital, VeUore, India 632 004. Accepted for publication April 22, 1992
be closed fully. He did not have stridor or other signs of airway obstruction though there was a history of noisy breathing. He was premedicated with trimeprazine 42 mg orally and hyoscine 0.2 mg IM one hour before the procedure. Monitoring was commenced with a cardioscope and a pulse oximeter. He was given an inhalationat induction with nitrous oxide, oxygen and halothane after which an intravenous line was inserted. As the level of anaesthesia deepened, it became increasingly difficult to maintain a patent airway. Two people were needed to maintain the airway, one solely for lifting the mandible forward. Laryngoscopy was attempted when he was deeply anaesthetised but it was impossible to see even the epiglottis. A size 2 LMA was inserted with no difficulty and the patient was maintained on spontaneous respiration till the end of surgery which lasted three hours. The neck contracture was released and skin grafting was carried out. The LMA was removed when he was awake, after oropharyngeal suction. The graft became infected and the patient needed further surgery two weeks later. On this occasion AnaestheslG and Intensn'e Care, Vol. 20, No. 4. NOI'ember, 1992
519
CASE REPORT
the neck, although held in flexion, could be extended by about twenty degrees more than before the first anaesthetic. This time we decided to attempt endotracheal intubation as the procedure was more extensive and necessitated repositioning during the course of the operation. From our previous experience we knew that intubation was likely to be difficult, and that it might be necessary to intubate over a bougie. While planning our anaesthetic technique, we found that the smallest available bougie could only pass through a 5.5 mm endotracheal tube, which was judged to be too big for our patient. Smaller endotracheal tubes were found to pass easily through a size 2 LMA when they were rotated so that their bevel faced backwards. Hence we decided to pass the endotracheal tube directly through the LMA. The patient was premedicated with atropine 0.15 mg and given an inhalational induction as before. When he was deep enough a size 2 LMA was inserted with ease. After again deepening the level of anaesthesia a Portex 5.0 mm uncuffed tube was inserted through the LMA, but it was not possible to push it beyond the end of the mask even with rotation of the tube. A 4.5 mm tube could be pushed through the LMA, but it only entered the trachea on the fourth attempt, after the head was extended as much as possible. Tube placement was confirmed by auscultation and the LMA was then removed. The subsequent course of the anaesthetic was uneventful, and the patient was extubated when awake. DISCUSSION
The role of the LMA in the management of the difficult airway is twofold. First, it can be inserted in order to obtain a patent airway. This has been done in adults4-8 as well as in the paediatric age groUp.9-12 Mason and Bingham9 demonstrate the safety of the LMA in a series of two hundred children including sixteen patients with difficult airways. There have also been reports of the use of the LMA in two patients with Pierre-Robin syndrome 10,1 I and in a six-year-old boy with arthrogryphosis mUltiplexa. 12 The LMA may also be used as an aid to intubation, and two techniques have been described. Brain l3 and McClune l4 suggested that the endotracheal tube may be passed directly through the LMA. In a recent study of one hundred adults undergoing elective surgery, intubation through the LMA with a 6.0 mm tube was successful in 90% of cases without cricoid pressure but in only 56% of cases when cricoid pressure was applied,15 Alternatively, a gum-elastic bougie can be inserted through the LMA and a suitable endotracheal tube can be threaded over it after removal of the mask. 16 This has been reported in Anaesthesia and Intensive Care. Vo/. 20. No. 4. November. 1992
two patients with difficult airways, both adults. 17 There are two problems in using the LMA to aid intubation in children. The mask is often too small to allow the passage of an appropriate sized endotracheal tube, especially when the LMA is in place. This happened in our patient. Also it is often difficult to obtain small enough bougies. Another problem is that even when the LMA is correctly placed, the oesophageal opening is often included within the cuff. This has actually been observed through the fibreoptic laryngoscope,18 and implies that a bougie or tube passed through the LMA can enter the oesophagus as easily as the trachea. In our patient, intubation was possible only on the fourth attempt, after extension of the head. We have not found any reports of the LMA having been used to aid intubation in children. In conclusion, the laryngeal mask airway is an effective aid in managing patients with difficult airways, in both adults and children. We report the anaesthetic management of a child with burns contractures and demonstrate the use of the LMA to aid intubation. REFERENCES
I. Brain AIJ. The Laryngeal Mask - a new concept in airway management. Br J Anaesth 1983; 55:801-805. 2. Brain AIJ, McGhee TD, McAteer El et al. The Laryngeal Mask airway. Development and trials of a new type of airway. Anaesthesia 1985; 40: 3 56-361. 3. Brain AIJ. Further developments of the Laryngeal Mask (letter). Anaesthesia 1989; 44:530. 4. Brain AIJ. Three cases of difficult intubation overcome by the Laryngeal Mask airway. Anaesthesia 1985; 40:353-355. 5. Thomson KD, Ordman AJ, Parkhouse N, Morgan BD. Use of the Laryngeal Mask airway in anticipation of difficult tracheal intubation. Br J PIast Surg 1989; 42:478-480. 6. Russell R, Judkins KC. The Laryngeal Mask airway and facial burns (letter). Anaesthesia 1990; 45:894. 7. Calder I, Ordman AJ, Jackowski A, Crockard HA. The Brain Laryngeal Mask airway. An alternative to emergency tracheal intubation. Anaesthesia 1990; 45:137-139. 8. AlIen JG, Flower EA. The Brain Laryngeal Mask. An alternative to difficult intubation. Br Dent J 1990; 168:202-204. 9. Mason DG, Bingham RM. The Laryngeal Mask airway in children. Anaesthesia 1990; 45:760-763. 10. Beveridge ME. Laryngeal Mask anaesthesia for repair of cleft palate. Anaesthesia 1989; 44:656-657. 11. Denny NM, Desilver KD, Webber PA. Laryngeal Mask airway for emergency tracheostomy in a neonate (letter). Anaesthesia 1990; 45:895. 12. Ravalia A, Goddard JM. The Laryngeal Mask and difficult tracheal intubation (letter). Anaesthesia 1990; 45: 168. 13. Brain AIJ. The Laryngeal Mask airway - a possible new solution to airway problems in the emergency situation. Arch Emerg Med 1984; 1:229-232.
520
G.
NATH AND
14. McC1une S, Regan M, Moore J. Laryngeal Mask airway for caesarean section. Anaesthesia 1990; 45:227-228. 15. Health ML, Allagian J. Intubation through the Laryngeal Mask. A technique for unexpected difficult intubation. Anaesthesia 1991; 46:545-548. 16. Allison A, McCrory J. Tracheal placement ofa gum elastic bougie using the Laryngeal Mask airway (letter). Anaesthesia 1990; 45:419-420.
V.
MAJOR
17. Chadd GO, Ackers JW, Bailey PM. Difficult intubation aided by the Laryngeal Mask airway (letter). Anaesthesia 1989; 44: 1015. 18. Payne J. The use of the Fibreoptic Laryngoscope to confirm the position of the Laryngeal Mask. Anaesthesia 1989; 44:865.
Prolonged Malignant Hyperthermia in the Absence of Triggering Agents N. POLLOCK,* M. HODGEst AND J. SENDALq
Department of Anaesthesia and Intensive Care. Palmerston North Hospital, Palmerston North, New Zealand Key Words: ANAESTHESIA; COMPLICATIONS: malignant hyperthermia, anaesthetic triggering agents, stress, creatine kinase, dantrolene
Episodes of malignant hyperthermia (MH) occurring in the recovery room or even later are well-documented. I. 3 Reports of MH developing in the absence oftriggering agents are few, particularly postoperatively,4,5 and in general these were mild reactions. A case is presented where a probable MH reaction developed in the absence of triggering agents, and continued several days into the postoperative period, requiring large doses of dantrolene for management. CASE REPORT An eighteen-year-old, 90 kg male presented for closed insertion of a Russel-Taylor rod into an unstable right tibial fracture, and excision of a loose talar fragment in the right ankle. Past anaesthetic and family history A diagnosis of malignant hyperthermia had been made at another hospital after an anaesthetic at the age of sixteen for drainage of nasal abscess. He had developed masseter spasm following the administration of thiopentone and suxamethonium, and this had intensified with the addition of isoflurane. Tracheal intubation was impossible and he was allowed to wake up. He was *F.F.A.R.A.CS., Specialist Anaesthetist. tF.F.A.R.A.CS., Director, Department of Anaesthesia and Intensive Care. tF.F.A.R.A.CS., Specialist Anaesthetist. Address for ConespondencelReprints: Dr. A. N. Pollock, cl· Palmerston North Hospital, Private Bag, Palmerston North, New Zealand. Accepted for publication April 22, 1992
admitted to intensive care unit (ICV), and responded to cooling measures only. Creatine kinase was measured at 59,160 IV (normal 20-215 IV), two days postoperatively. He had had no other previous general anaesthetic. In 1989 he received a regional block for suturing of fingers following a crush injury. During this procedure he developed tachycardia, hypertension and anxiety which was felt to be out of proportion to the stimulus received. The patient is a member of a large family susceptible to MH. His mother died suddenly at the end of an anaesthetic for appendicectomy at the age of twenty in 1973 (agents used included two 30 mg doses of suxamethonium and halothane), and a first cousin survived a fulminant episode of MH in 1987. Anaesthesia He was premedicated with midazolam 15 mg and metoclopramide 10 mg. Monitoring was established using an electrocardiogram, pulse oximetry, rectal temperature probe, radial arterial line and end-tidal C02 (ETC02)' Hourly urine outputs were recorded. Anaesthesia was induced at I 700 hours with thiopentone 400 mg and fentanyl 500 mcg and was maintained with 66% N 20 and incremental doses of fentanyl (2 mg total). The gases were administered through a vapour-free circle system reserved for MH patients. Muscle relaxation was provided with vecuronium 10 mg. The ventilator was set at 800 ml tidal volume and 8 breaths per minute (bpm) to maintain ETC0 2 at 36 Anal'~·th(,sJa
and Intenso'(' Care, f ·of. 20.
/\'0. 4,
Norember. 1992
