356
Correspondence
Safe use of propofol in a patient with acute intermittent porphyria. British Journal of Anaesthesia 1988; 60: 109-1 I . [5] MEISSNER PN, HARRISON GG, HIFT RJ. Propofol as an 1V anaesthetic agent in variegate porphyria. British Journal of Anaesthesia 1991; 66:60-5.
[6] AITKENHEAD AR, PEPPERMAN ML, WILLATTS SM, COATES PD, PARK GR, BODENHAMAR, COLLINS CH, SMITH MB, LEDINGHAM IM, WALLACE PGM. Comparison of propofol and midazolam for sedation in critically ill patients. Lancet 1989; 2:
704-9.
Propofol and mono-amine oxidase inhibitors The problem of anaesthesia for emergency surgery in patients receiving monoamine oxidase inhibitors (MAOI) for depressive illness invites varying opinions as to the safest drugs to administer peroperatively. Pethidine is known to be absolutely contraindicated [I] and morphine has been recommended as the drug of choice, although great potentiation of its depressive effects have been noted [2]. Similar potentiation of the effects of barbiturates have also been recorded [3]. Very little information is available about the safety of the shorter acting opioids or propofol in these circumstances, although the combination of alfentanil and propofol has been used uneventfully [4]. A 72-year-old woman presented for plating of a badly displaced fracture of her mandible. She had been receiving phenelzine for 15 years and was known to have a hiatus hernia, but was relatively asymptomatic. Ten years previously she had undergone an inguinal hernia repair and the patient clearly stated that she had continued phenelzine up to the time of surgery; unfortunately no anaesthetic record was available. Premedication comprised ranitidine 150 mg. Following pre-oxygenation and administration of propofol 80 mg, cricoid pressure was applied and anaesthesia continued by inhalation of enflurane in oxygen and nitrous oxide. Suxamethonium was avoided because the drug has a prolonged effect in MA01 therapy due to a decrease in cholinesterase concentration [I]. Nasal intubation was achieved easily and anaesthesia was
maintained with spontaneous ventilation. The systolic blood pressure remained at 120-130 mmHg throughout the procedure with a steady pulse rate. Analgesia was provided by diclofenac 75 mg intramuscularly and surgical infiltration of 0.25% plain bupivacaine. The patient awoke rapidly and was pain free. Further doses of diclofenac were provided for postoperative analgesia. This report supports the view that propofol is a suitable agent for use in patients receiving concurrent M A 0 1 therapy. Walton Hospital, Liverpool L9 IAE
C.A. HODGSON
References [ I ] STACKCG, ROGERSP, LINTERSPK. Monoamine oxidase inhibitors and anaesthesia. A review. British Journal q / Anaesthesia 1988; 60:222-1. [2] RIVERS N, HORNERB. Possible lethal reaction between nardil and dextromethorphan. Canadian Medical Association Journal 1970; 103 85. [3] JENKINS LC, GRAVES HB. Potential hazards of psychoactive drugs in association with anaesthesia. Canadian Anaestheti.st.s’ Society Journal 1965; 1 2 121-8. [4] POWELL H. Use of alfentanil in a patient receiving monoamine oxidase inhibitor therapy. British Journal CJ/ Anaesthesia 1990; 64: 528-9.
Failed tracheal intubation I am concerned by yet another report of deaths from failed tracheal intubation (Anaesthesia 1991; 4 6 962-966). If patients are to die at all, it should be because of failed cricothyroidotomy and not failed orotracheal intubation. I would be most interested to know how many of the seven cases of primary failure to intubate the trachea (as opposed to unrecognised oesophageal intubation) had a cricothyroidotomy, at what stage of hypoxia it was carried out, if at all, what exactly was the cause of death (i.e. failure to ventilate, aspiration, etc). It could be that some of these patients might have been salvaged by successful, early cricoth yroidotomy? I suspect that, like the failure to consider oesophageal intubation, professional intransigence results in a refusal to admit ‘failed’ orotracheal intubation, particularly by senior anaesthetists, and that both lack of experience and fear of complications makes us resistant to the life-saving surgical approach. Confidence can be acquired by performing and teaching surgical and needle cricothyroidotomy on cadavers. I have recently trained three senior house officers, all of whom inserted a size 7 mm cuffed tube into the trachea via the cricothyroid membrane in under 25 s; they had no previous experience and only a scalpel and a pair of forceps. This formal surgical approach is recommended in preference to minitracheotomy or a Seldinger technique, because it is quicker. Needle cricothyroidotomy is not much faster, requires unfamiliar high pressure ventilation via often unreliable Heath-Robinson attachments and is associated with a
substantial risk of barotrauma. I strongly urge all those anaesthetists who are a t high risk of encountering difficult airways, particularly obstetric anaesthetists, to visit their local anatomy or pathology department, if they do not have prior experience of cricothyroidotomy. Correspondents have recently discussed alternative methods of intubation, such as the laryngeal mask [I]. I agree that these techniques should be practised, but consider that they are only applicable before hypoxia has supervened, in the patient who can still breathe spontaneously or be adequately ventilated by facemask, but cannot be intubated. Even then, the necessary release of cricoid pressure and continued risk of aspiration (21 may justify the surgical introduction of a cuffed tube. In the nightmare scenario of failure to both intubate the trachea and ventilate the lungs effectively, with an Spo, rapidly falling below go%, one must have the courage to perform cricothyroidotomy immediately. The Royal Naval Hospital Haslar, Gosport. Hants PO12 2AA
S.Q.M. TIGHE
References [ I ] HEATHML, ALLAGAIN J. Intubation through the laryngeal mask. Anaesthesia 1991; 46: 985-6. [2] ANSERMINOJM, BLCGG CE, CARRIELES. Failed tracheal intubation at Caesarean section and the laryngeal mask. British Journal oy Anaesrhesia 1992; 68: 1 18.
Correspondence
Safe use of propofol in a patient with acute intermittent porphyria. British Journal of Anaesthesia 1988; 60: 109-1 I . [5] MEISSNER PN, HARRISON GG, HIFT RJ. Propofol as an 1V anaesthetic agent in variegate porphyria. British Journal of Anaesthesia 1991; 66:60-5.
[6] AITKENHEAD AR, PEPPERMAN ML, WILLATTS SM, COATES PD, PARK GR, BODENHAMAR, COLLINS CH, SMITH MB, LEDINGHAM IM, WALLACE PGM. Comparison of propofol and midazolam for sedation in critically ill patients. Lancet 1989; 2:
704-9.
Propofol and mono-amine oxidase inhibitors The problem of anaesthesia for emergency surgery in patients receiving monoamine oxidase inhibitors (MAOI) for depressive illness invites varying opinions as to the safest drugs to administer peroperatively. Pethidine is known to be absolutely contraindicated [I] and morphine has been recommended as the drug of choice, although great potentiation of its depressive effects have been noted [2]. Similar potentiation of the effects of barbiturates have also been recorded [3]. Very little information is available about the safety of the shorter acting opioids or propofol in these circumstances, although the combination of alfentanil and propofol has been used uneventfully [4]. A 72-year-old woman presented for plating of a badly displaced fracture of her mandible. She had been receiving phenelzine for 15 years and was known to have a hiatus hernia, but was relatively asymptomatic. Ten years previously she had undergone an inguinal hernia repair and the patient clearly stated that she had continued phenelzine up to the time of surgery; unfortunately no anaesthetic record was available. Premedication comprised ranitidine 150 mg. Following pre-oxygenation and administration of propofol 80 mg, cricoid pressure was applied and anaesthesia continued by inhalation of enflurane in oxygen and nitrous oxide. Suxamethonium was avoided because the drug has a prolonged effect in MA01 therapy due to a decrease in cholinesterase concentration [I]. Nasal intubation was achieved easily and anaesthesia was
maintained with spontaneous ventilation. The systolic blood pressure remained at 120-130 mmHg throughout the procedure with a steady pulse rate. Analgesia was provided by diclofenac 75 mg intramuscularly and surgical infiltration of 0.25% plain bupivacaine. The patient awoke rapidly and was pain free. Further doses of diclofenac were provided for postoperative analgesia. This report supports the view that propofol is a suitable agent for use in patients receiving concurrent M A 0 1 therapy. Walton Hospital, Liverpool L9 IAE
C.A. HODGSON
References [ I ] STACKCG, ROGERSP, LINTERSPK. Monoamine oxidase inhibitors and anaesthesia. A review. British Journal q / Anaesthesia 1988; 60:222-1. [2] RIVERS N, HORNERB. Possible lethal reaction between nardil and dextromethorphan. Canadian Medical Association Journal 1970; 103 85. [3] JENKINS LC, GRAVES HB. Potential hazards of psychoactive drugs in association with anaesthesia. Canadian Anaestheti.st.s’ Society Journal 1965; 1 2 121-8. [4] POWELL H. Use of alfentanil in a patient receiving monoamine oxidase inhibitor therapy. British Journal CJ/ Anaesthesia 1990; 64: 528-9.
Failed tracheal intubation I am concerned by yet another report of deaths from failed tracheal intubation (Anaesthesia 1991; 4 6 962-966). If patients are to die at all, it should be because of failed cricothyroidotomy and not failed orotracheal intubation. I would be most interested to know how many of the seven cases of primary failure to intubate the trachea (as opposed to unrecognised oesophageal intubation) had a cricothyroidotomy, at what stage of hypoxia it was carried out, if at all, what exactly was the cause of death (i.e. failure to ventilate, aspiration, etc). It could be that some of these patients might have been salvaged by successful, early cricoth yroidotomy? I suspect that, like the failure to consider oesophageal intubation, professional intransigence results in a refusal to admit ‘failed’ orotracheal intubation, particularly by senior anaesthetists, and that both lack of experience and fear of complications makes us resistant to the life-saving surgical approach. Confidence can be acquired by performing and teaching surgical and needle cricothyroidotomy on cadavers. I have recently trained three senior house officers, all of whom inserted a size 7 mm cuffed tube into the trachea via the cricothyroid membrane in under 25 s; they had no previous experience and only a scalpel and a pair of forceps. This formal surgical approach is recommended in preference to minitracheotomy or a Seldinger technique, because it is quicker. Needle cricothyroidotomy is not much faster, requires unfamiliar high pressure ventilation via often unreliable Heath-Robinson attachments and is associated with a
substantial risk of barotrauma. I strongly urge all those anaesthetists who are a t high risk of encountering difficult airways, particularly obstetric anaesthetists, to visit their local anatomy or pathology department, if they do not have prior experience of cricothyroidotomy. Correspondents have recently discussed alternative methods of intubation, such as the laryngeal mask [I]. I agree that these techniques should be practised, but consider that they are only applicable before hypoxia has supervened, in the patient who can still breathe spontaneously or be adequately ventilated by facemask, but cannot be intubated. Even then, the necessary release of cricoid pressure and continued risk of aspiration (21 may justify the surgical introduction of a cuffed tube. In the nightmare scenario of failure to both intubate the trachea and ventilate the lungs effectively, with an Spo, rapidly falling below go%, one must have the courage to perform cricothyroidotomy immediately. The Royal Naval Hospital Haslar, Gosport. Hants PO12 2AA
S.Q.M. TIGHE
References [ I ] HEATHML, ALLAGAIN J. Intubation through the laryngeal mask. Anaesthesia 1991; 46: 985-6. [2] ANSERMINOJM, BLCGG CE, CARRIELES. Failed tracheal intubation at Caesarean section and the laryngeal mask. British Journal oy Anaesrhesia 1992; 68: 1 18.
