- Email: [email protected]
ADVERSE REACTIONS TO I.V. ANAESTHETICS
CORRESPONDENCE
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r
manifold outlet to prevent such a loss of oxygen. Bishop, Levick and Hodgson (1967) reported two accidents caused by this "fundamental fault in the design of the Boyle machine"; Katz (1968) and Liew and Ganendran (1973) reported similar accidents. In 1975, a report by Gupta and Varshneya, of a death attributable to the escape of oxygen through the washer intended to seal the top of a downstream flowmeter in a Boyletype machine, drew further comment (Muliyil, 1976; RcndellBaker, 1976; Varshney, 1976) through correspondence. There are two ways to eliminate this hazard. The simplest, mechanically, in the Boyle-type machine is to relocate the oxygen flowmeter to the right-hand side of the manifold. This could be performed in the hospital by the manufacturer's serviceman, thus requiring that the apparatus be out of service for a minimum time. This solution will require a re-education programme for anaesthetists similar to that mounted when the colours of gas cylinders were changed in the 1950's. The other more difficult and expensive solution would be to fit an internal conduit in the top of the flowmcter manifold to conduct the oxygen directly to the outlet of the manifold as described by Katz (1969). This would require the return of the flowmeter manifold to the manufacturer to be rebuilt or the purchase of a new flowmeter manifold incorporating the oxygen conduit. With present hospital budget problems the first solution— "oxygen on the right"—has both financial and mechanical arguments in its favour as a safety measure. After all, Henry Ford managed to persuade our fathers to change from a hand throttle on the steering wheel on his Model T to a foot-accelerator on the right with his Model A . . . would it really be so difficult to change to "oxygen to the right?" LESLIE RENDELL-BAKER
California, U.S.A. REFERENCES
Bishop, C , Levick, C. H., and Hodgson, C. (1967). A design fault in the Boyle apparatus. Br. J. Anaesth., 39, 908. Eger, E. I. n, Hylton, R. R., Irwin, R. H. et al. (1963). Anesthetic flowmeter sequence—a cause for hypoxia. Anesthesiology, 24, 396. Gupta, B. L., and Varshneya, A. K. (1975). Anesthetic accident caused by unusual leakage of Rotameter. Br.J. Anaesth., 47, 805. Katz, D. (1968). Recurring cyanosis of intermittent mechanical origin in anesthetized patient. Anesth. Analg. [Cleve.), 47, 233. (1969). Increasing the safety of anesthesia machines. I: Further modification of the Drager machine: II: Considerations for standardization of certain basic components. Anesth. Analg. (Cleve.), 48, 242. Uew, P. C , and Ganendran, A. (1973). Oxygen failure: a potential danger with air-flowmeters in anaesthetic machine with remote controlled needle valves. Br. J. Anaesth., 45, 1165. Muliyil, J. A. (1976). Anaesthetic accident caused by unusual leakage of Rotameter. Br. J. Anaesth., 48, 499. Powell, J. (1981). Leak from an oxygen flowmeter. Br. J. Anaesth., 53, 671. Rendell-Baker, L. (1976). Anaesthetic accident caused by unusual leakage or Rotameter. Br. J. Anaesth., 48, 500. Varshney, J. P. (1076). Anaesthetic accident caused by unusual leakage of Rotameter. Br. J. Anaesth., 48, 500.
HUNTCNGTON'J CHOREA
Sir,—Further to the article by Farina and Rauscher (1977), we report the successful anaesthetic management of two patients with Huntington's chorea. Two brothers presented with chronic left lower lobe consolidation and pleural effusion. Left pleura] decorrication was the Surgical treatment indicated. The elder (aged 25 yr) had frank manifestations of Huntington's chorea (dysarthria, dementia, atoxia, and choreifonn movements), while the younger (aged 19 yr) had early signs of the disease (ataxia, and occasional choreifonn movements). The patients received papaveretum and hyoscine before operation. Anaesthesia was induced with thiopentone. Suxamethonium facilitated bronchoscopy and tracheal intubation with a Robertshaw double-lumen tube. Further muscle relaxation was provided by pancuronium and analgesia by fentanyl and nitrous oxide. Both operations were uneventful. Neuromuscular blockade was antagonized with neostigmine and atropine. Davies (1966) suggested that patients with Huntington's chorea might be unduly sensitive to barbiturates. This problem did not arise with our patients. Gualandi and Bonfanti (1968) postulated that prolonged apnoea, as a result of abnormal plasma cholinesterase activity, may follow the use of depolarizing muscle relaxants. We measured plasma cholinesterasec concentrations before operation in both patients: Plasma cholinesterase: 0.73 and 0.61 iu ml"' (riormal values 0.6-1.4 iu ml" 1 Dibucaine numbers: 79 and 83 Fluoride numbers: 69 and 57 Probable genotype for both patients: E, U E, U We agree with the suggestion of Farina and Rauscher that the anaesthetic requirements of patients with Huntington's chorea can be provided by a nitrous oxide-narcotic combination, and successful management of myoneural blockade by pancuronium. M. G. BROWNE R. CROSS
Cardiff
REFERENCES
Davies, D. D. (1966). Abnormal response to anaesthesia in a case of Huntington's chorea. Br. J. Anaesth., 38, 490. Farina, J., and Rauscher, L. A. (1977). Anaesthesia and Huntington's chorea. A report of two cases. Br. J. Anaesth., 49, 1167. Gualandi, W., and Bonfanti, G. (1968). A case of prolonged apnoea in Huhtington's chorea. Ada Anaesthesiol. (Padova), 19, (Suppl. 6), 235.
ADVERSE REACTIONS TO I.V. ANAESTHETICS
In response to enquiries regarding the number of patients studied by Drs Beamish and Brown (Br.J. Anaesth., 53,55), we are pleased to publish the following letter from Dr Brown: The number of administrations of each induction agent— from which we calculated frequencies of reactions—was the total number of administrations of the anaesthetic including those in which other drugs, including relaxants, were used.
Downloaded from http://bja.oxfordjournals.org/ at University of Sussex on July 18, 2015
r-
1367
BRITISH JOURNAL OF ANAESTHESIA
1368 Our sentence "Patients who received muscle relaxants were not included in this study" is misleading and is the source of confusion. The sentence referred to the design of the study in which we intended to include only those reactions which were clearly the result of an induction agent and to exclude any reactions in which a relaxant had been used at induction. This was to avoid reactions where it was not absolutely clear whether the induction agent or the relaxant had caused the problem. In the end we did not have to exclude any reactions on this basis, which is perhaps a matter for comment. We have therefore calculated the minimum frequency of reactions for each drug. We believe this is the best way to present these figures.
P.V.C. CUFFS AND LIGNOCAINE-6ASE AEROSOL
REFERENCES
Douglas, J. G., Nimmo, W. S., Wanless, R., Jarvie, D. R., Heading, R. C , and Finlayson, N. D. C. (1980). Sedation for upper gastrointestinal endoscopy. A comparison of oral temazepam and i.v. diazepam. Br. J. Anaesth., 52, 811. Harris, P. A. (1981). Oral temazepam and i.v. diazepam. Br.J. Anaesth., 53, 551. Nimmo, W. S. (1981). Oral temazepam and i.v. diazepam. Br.
J. Anaesth., 53,551.
K. D. JAYASURIYA W. F. WATSON
Portex Ltd, Hythe, Kent REFERENCES
Bristow, G. M., and Watson, W. F. (1958). Cohesive energy density of polymers. Trans. Farad. Soc., 54, 1742. Horatz, K. (1977). Take care when spraying PVC tubes with local anaesthetic. Anaesth. Inform., 18, 519.
1 1 4
Downloaded from http://bja.oxfordjournals.org/ at University of Sussex on July 18, 2015
Sir,—Horatz (1977) observed that an aerosol of lignocaine base can cause pin-holes in the inflated cuffs of endotntcheal tubes, and suggested that lignocaine-base aerosol should not be used when it could be sprayed on p.v.c. cuffs. We have noted that a droplet of the aerosol on a p.v.c. cuff causes: (1) no effect on its inflation; (2) occurrence of a pin-hole after a short interval; (3) the raising of a blister on the inflated cuff or, (4) sudden rupture of the cuff. These different effects depend on the size of the droplet, whether it spreads or is localized, and the extent of stretch of the cuff membrane. The explanation which we suggest is that the aerosol contains DAVID T. BROWN a swelling agent for the cuff. The different effects are explicable Edinburgh in terms of the rate of its diffusion and the changes it causes on the mechanical properties of the cuff membrane. Swelling agents soften a polymer and decrease its tensile strength. If it is SEDATION FOR UPPER GASTROINTESTINAL ENDOSCOPY in insufficient localized quantity, it merely causes a marginal Sir,—In my practice, which differs from that of Dr Nimmo softening of the cuff membrane and an insignificant increase in (Douglas et al., 1980; Nimmo, 1981), the patients need cuff volume (effect (1) above). If the tensile strength in a small guaranteed and immediate sedation; I doubt if temazepam can area is reduced below the tension in the membrane at that point, a micro-rupture occurs (pin-hole formation). If a larger area is provide this (Harris, 1981). After more than 12 000 gastroscopies with 30-40 patients per softened, the pressure uniformly exerted on the inside of the session, the "turn around time" for outpatients averages 5 min membrane causes the softer region to stretch further and so comprising: about 1 min for injection, 1—2 min for gastroscopy, form a blister. Finally, if a substantial amount of swelling agent and about 2 min to remove the patient from the table and is rapidly absorbed in a larger area, a tear occurs. We made an aerosol with the same propellants containing position the next one. Some patients, particularly those 10% di-octyl-phthalate, a typical plasticizer for p.v.c. This bleeding briskly or when multiple biopsies are needed, take aerosol produced all the above effects. much longer to examine. To confirm that Xylocaine Spray contained a swelling agent, I use pre-mixed diazepam and hyoscine (Buscopan) 20 mg each. Mn*r fit patients receive the full dose in less than 30s pieces of cuff were immersed for 1 h in the pressurized liquid. without titration (which would delay the procedure); liic After leaving in nir for the propellants to evaporate, the cuff elderly or frail receive less. In almost all patients adequate and material increased in weight by between 10 and 157o. The fluorocarbon propellants themselves did not evince rapid sedation ensues; the vast majority cannot recall the examination, which is a major reason why most are willing to any swelling action nor adversely affect an inflated cuff. have the procedure repeated. None has had respiratory Lignocaine-base is otherwise the only ingredient in significant quantity and appears to be the causative agent. This is not problems. More patients given temazepanl could recall the procedure; surprising from its dissolution in a wide range of organic this suggests the sedation was less than with diazepam despite a materials up to the polarity of methanol—bracketing the 10-min interval between the injection and endoscopy, by which polarity of p.v.c. As further confirmation, lignocaine-base time the peak sedative effect would have passed in many. In my crystals placed on an inflated cuff were absorbed into it and after experience inadequate sedation prolongs the examination and 2-5 h could cause pin-holes and blisters. However, lignocaine hydrochloride (the salt) in solution or in crystal form had no makes patients reluctant to re-attend. For the few patients with recurrent thrombophlebitis from effect on p.v.c. cuffs. Hence, as confirmed experimentally, gels i.v. diazepam, I will certainly use oral temazepam. But in my or salves of the salt have no adverse effect on inflated p.v.c. peculiar type of endoscopy practice, there is as yet no substitute cuffs. This correlates with the insolubility of the salt in p.v.c. and in organic materials including cyclohexane with a solubility for i.v. diazepam. parameter of 11.4, but in ethanol of 12.7, whereas p.v.c. has a K. D. BARDHAN solubility parameter of 9.5. Rotherham Astra Pharmaceuticals Ltd inform us that Xylocaine Spray is not recommended when it may contact p.v.c. cuffs. Xylocaine 4% topical and 2% gel—which contain the salt and not the base—are recommended. The above findings are in harmony with these recommendations.
r
r
manifold outlet to prevent such a loss of oxygen. Bishop, Levick and Hodgson (1967) reported two accidents caused by this "fundamental fault in the design of the Boyle machine"; Katz (1968) and Liew and Ganendran (1973) reported similar accidents. In 1975, a report by Gupta and Varshneya, of a death attributable to the escape of oxygen through the washer intended to seal the top of a downstream flowmeter in a Boyletype machine, drew further comment (Muliyil, 1976; RcndellBaker, 1976; Varshney, 1976) through correspondence. There are two ways to eliminate this hazard. The simplest, mechanically, in the Boyle-type machine is to relocate the oxygen flowmeter to the right-hand side of the manifold. This could be performed in the hospital by the manufacturer's serviceman, thus requiring that the apparatus be out of service for a minimum time. This solution will require a re-education programme for anaesthetists similar to that mounted when the colours of gas cylinders were changed in the 1950's. The other more difficult and expensive solution would be to fit an internal conduit in the top of the flowmcter manifold to conduct the oxygen directly to the outlet of the manifold as described by Katz (1969). This would require the return of the flowmeter manifold to the manufacturer to be rebuilt or the purchase of a new flowmeter manifold incorporating the oxygen conduit. With present hospital budget problems the first solution— "oxygen on the right"—has both financial and mechanical arguments in its favour as a safety measure. After all, Henry Ford managed to persuade our fathers to change from a hand throttle on the steering wheel on his Model T to a foot-accelerator on the right with his Model A . . . would it really be so difficult to change to "oxygen to the right?" LESLIE RENDELL-BAKER
California, U.S.A. REFERENCES
Bishop, C , Levick, C. H., and Hodgson, C. (1967). A design fault in the Boyle apparatus. Br. J. Anaesth., 39, 908. Eger, E. I. n, Hylton, R. R., Irwin, R. H. et al. (1963). Anesthetic flowmeter sequence—a cause for hypoxia. Anesthesiology, 24, 396. Gupta, B. L., and Varshneya, A. K. (1975). Anesthetic accident caused by unusual leakage of Rotameter. Br.J. Anaesth., 47, 805. Katz, D. (1968). Recurring cyanosis of intermittent mechanical origin in anesthetized patient. Anesth. Analg. [Cleve.), 47, 233. (1969). Increasing the safety of anesthesia machines. I: Further modification of the Drager machine: II: Considerations for standardization of certain basic components. Anesth. Analg. (Cleve.), 48, 242. Uew, P. C , and Ganendran, A. (1973). Oxygen failure: a potential danger with air-flowmeters in anaesthetic machine with remote controlled needle valves. Br. J. Anaesth., 45, 1165. Muliyil, J. A. (1976). Anaesthetic accident caused by unusual leakage of Rotameter. Br. J. Anaesth., 48, 499. Powell, J. (1981). Leak from an oxygen flowmeter. Br. J. Anaesth., 53, 671. Rendell-Baker, L. (1976). Anaesthetic accident caused by unusual leakage or Rotameter. Br. J. Anaesth., 48, 500. Varshney, J. P. (1076). Anaesthetic accident caused by unusual leakage of Rotameter. Br. J. Anaesth., 48, 500.
HUNTCNGTON'J CHOREA
Sir,—Further to the article by Farina and Rauscher (1977), we report the successful anaesthetic management of two patients with Huntington's chorea. Two brothers presented with chronic left lower lobe consolidation and pleural effusion. Left pleura] decorrication was the Surgical treatment indicated. The elder (aged 25 yr) had frank manifestations of Huntington's chorea (dysarthria, dementia, atoxia, and choreifonn movements), while the younger (aged 19 yr) had early signs of the disease (ataxia, and occasional choreifonn movements). The patients received papaveretum and hyoscine before operation. Anaesthesia was induced with thiopentone. Suxamethonium facilitated bronchoscopy and tracheal intubation with a Robertshaw double-lumen tube. Further muscle relaxation was provided by pancuronium and analgesia by fentanyl and nitrous oxide. Both operations were uneventful. Neuromuscular blockade was antagonized with neostigmine and atropine. Davies (1966) suggested that patients with Huntington's chorea might be unduly sensitive to barbiturates. This problem did not arise with our patients. Gualandi and Bonfanti (1968) postulated that prolonged apnoea, as a result of abnormal plasma cholinesterase activity, may follow the use of depolarizing muscle relaxants. We measured plasma cholinesterasec concentrations before operation in both patients: Plasma cholinesterase: 0.73 and 0.61 iu ml"' (riormal values 0.6-1.4 iu ml" 1 Dibucaine numbers: 79 and 83 Fluoride numbers: 69 and 57 Probable genotype for both patients: E, U E, U We agree with the suggestion of Farina and Rauscher that the anaesthetic requirements of patients with Huntington's chorea can be provided by a nitrous oxide-narcotic combination, and successful management of myoneural blockade by pancuronium. M. G. BROWNE R. CROSS
Cardiff
REFERENCES
Davies, D. D. (1966). Abnormal response to anaesthesia in a case of Huntington's chorea. Br. J. Anaesth., 38, 490. Farina, J., and Rauscher, L. A. (1977). Anaesthesia and Huntington's chorea. A report of two cases. Br. J. Anaesth., 49, 1167. Gualandi, W., and Bonfanti, G. (1968). A case of prolonged apnoea in Huhtington's chorea. Ada Anaesthesiol. (Padova), 19, (Suppl. 6), 235.
ADVERSE REACTIONS TO I.V. ANAESTHETICS
In response to enquiries regarding the number of patients studied by Drs Beamish and Brown (Br.J. Anaesth., 53,55), we are pleased to publish the following letter from Dr Brown: The number of administrations of each induction agent— from which we calculated frequencies of reactions—was the total number of administrations of the anaesthetic including those in which other drugs, including relaxants, were used.
Downloaded from http://bja.oxfordjournals.org/ at University of Sussex on July 18, 2015
r-
1367
BRITISH JOURNAL OF ANAESTHESIA
1368 Our sentence "Patients who received muscle relaxants were not included in this study" is misleading and is the source of confusion. The sentence referred to the design of the study in which we intended to include only those reactions which were clearly the result of an induction agent and to exclude any reactions in which a relaxant had been used at induction. This was to avoid reactions where it was not absolutely clear whether the induction agent or the relaxant had caused the problem. In the end we did not have to exclude any reactions on this basis, which is perhaps a matter for comment. We have therefore calculated the minimum frequency of reactions for each drug. We believe this is the best way to present these figures.
P.V.C. CUFFS AND LIGNOCAINE-6ASE AEROSOL
REFERENCES
Douglas, J. G., Nimmo, W. S., Wanless, R., Jarvie, D. R., Heading, R. C , and Finlayson, N. D. C. (1980). Sedation for upper gastrointestinal endoscopy. A comparison of oral temazepam and i.v. diazepam. Br. J. Anaesth., 52, 811. Harris, P. A. (1981). Oral temazepam and i.v. diazepam. Br.J. Anaesth., 53, 551. Nimmo, W. S. (1981). Oral temazepam and i.v. diazepam. Br.
J. Anaesth., 53,551.
K. D. JAYASURIYA W. F. WATSON
Portex Ltd, Hythe, Kent REFERENCES
Bristow, G. M., and Watson, W. F. (1958). Cohesive energy density of polymers. Trans. Farad. Soc., 54, 1742. Horatz, K. (1977). Take care when spraying PVC tubes with local anaesthetic. Anaesth. Inform., 18, 519.
1 1 4
Downloaded from http://bja.oxfordjournals.org/ at University of Sussex on July 18, 2015
Sir,—Horatz (1977) observed that an aerosol of lignocaine base can cause pin-holes in the inflated cuffs of endotntcheal tubes, and suggested that lignocaine-base aerosol should not be used when it could be sprayed on p.v.c. cuffs. We have noted that a droplet of the aerosol on a p.v.c. cuff causes: (1) no effect on its inflation; (2) occurrence of a pin-hole after a short interval; (3) the raising of a blister on the inflated cuff or, (4) sudden rupture of the cuff. These different effects depend on the size of the droplet, whether it spreads or is localized, and the extent of stretch of the cuff membrane. The explanation which we suggest is that the aerosol contains DAVID T. BROWN a swelling agent for the cuff. The different effects are explicable Edinburgh in terms of the rate of its diffusion and the changes it causes on the mechanical properties of the cuff membrane. Swelling agents soften a polymer and decrease its tensile strength. If it is SEDATION FOR UPPER GASTROINTESTINAL ENDOSCOPY in insufficient localized quantity, it merely causes a marginal Sir,—In my practice, which differs from that of Dr Nimmo softening of the cuff membrane and an insignificant increase in (Douglas et al., 1980; Nimmo, 1981), the patients need cuff volume (effect (1) above). If the tensile strength in a small guaranteed and immediate sedation; I doubt if temazepam can area is reduced below the tension in the membrane at that point, a micro-rupture occurs (pin-hole formation). If a larger area is provide this (Harris, 1981). After more than 12 000 gastroscopies with 30-40 patients per softened, the pressure uniformly exerted on the inside of the session, the "turn around time" for outpatients averages 5 min membrane causes the softer region to stretch further and so comprising: about 1 min for injection, 1—2 min for gastroscopy, form a blister. Finally, if a substantial amount of swelling agent and about 2 min to remove the patient from the table and is rapidly absorbed in a larger area, a tear occurs. We made an aerosol with the same propellants containing position the next one. Some patients, particularly those 10% di-octyl-phthalate, a typical plasticizer for p.v.c. This bleeding briskly or when multiple biopsies are needed, take aerosol produced all the above effects. much longer to examine. To confirm that Xylocaine Spray contained a swelling agent, I use pre-mixed diazepam and hyoscine (Buscopan) 20 mg each. Mn*r fit patients receive the full dose in less than 30s pieces of cuff were immersed for 1 h in the pressurized liquid. without titration (which would delay the procedure); liic After leaving in nir for the propellants to evaporate, the cuff elderly or frail receive less. In almost all patients adequate and material increased in weight by between 10 and 157o. The fluorocarbon propellants themselves did not evince rapid sedation ensues; the vast majority cannot recall the examination, which is a major reason why most are willing to any swelling action nor adversely affect an inflated cuff. have the procedure repeated. None has had respiratory Lignocaine-base is otherwise the only ingredient in significant quantity and appears to be the causative agent. This is not problems. More patients given temazepanl could recall the procedure; surprising from its dissolution in a wide range of organic this suggests the sedation was less than with diazepam despite a materials up to the polarity of methanol—bracketing the 10-min interval between the injection and endoscopy, by which polarity of p.v.c. As further confirmation, lignocaine-base time the peak sedative effect would have passed in many. In my crystals placed on an inflated cuff were absorbed into it and after experience inadequate sedation prolongs the examination and 2-5 h could cause pin-holes and blisters. However, lignocaine hydrochloride (the salt) in solution or in crystal form had no makes patients reluctant to re-attend. For the few patients with recurrent thrombophlebitis from effect on p.v.c. cuffs. Hence, as confirmed experimentally, gels i.v. diazepam, I will certainly use oral temazepam. But in my or salves of the salt have no adverse effect on inflated p.v.c. peculiar type of endoscopy practice, there is as yet no substitute cuffs. This correlates with the insolubility of the salt in p.v.c. and in organic materials including cyclohexane with a solubility for i.v. diazepam. parameter of 11.4, but in ethanol of 12.7, whereas p.v.c. has a K. D. BARDHAN solubility parameter of 9.5. Rotherham Astra Pharmaceuticals Ltd inform us that Xylocaine Spray is not recommended when it may contact p.v.c. cuffs. Xylocaine 4% topical and 2% gel—which contain the salt and not the base—are recommended. The above findings are in harmony with these recommendations.