1 100
Correspondence
A 66-year-old man with a 9 month history of headaches followed by left sided arm and facial weakness, presented for craniotomy, motor cortical mapping and excision of tumour. He was otherwise healthy. Following premedication with glycopyrronium 0.2 mg I h preoperatively, anaesthesia was induced with thiopentone 5 mg.kg-l followed by vecuronium 0.1 mg.kg-l. Alfentanil 1 .O mg was administered prior to tracheal intubation and anaesthesia was maintained with isoflurane 0.5% and nitrous oxide with 35% oxygen. An alfentanil infusion was commenced at 0.5 mg.kg-'.h-l and no further relaxant was required until the motor cortical mapping was completed. The expired CO, concentration was maintained at 3.5% using a Cape Waine ventilator. Prior to motor cortical mapping we tested for residual neuromuscular blockade using a peripheral nerve stimulator, which demonstrated a train-of-four ratio of 1 and the absence of tetanic fade. Movement of the patient's hand during cortical stimulation confirmed recovery of neuromuscular transmission. When the cortical mapping was completed the patient was reparalysed with vecuronium and the alfentanil infusion rate was halved initially and discontinued 30 min prior to reversal. Good operating conditions were achieved and the patient woke up quickly at the end of surgery and was alert during recovery.
Our use of alfentanil allowed ventilation of the lungs without neuromuscular blockade and without the risk of moving o r coughing, while avoiding the problems of deep inhalational anaesthesia. Alfentanil does not increase cerebral blood flow [2] and because of its pharmacokinetic profile, recovery is rapid following discontinuation of the infusion [3]. These features make it ideal for intracranial surgery. This use of alfentanil has not been described before for this purpose and we feel it has much to recommend it in this type of case. Hospitals for Sick Children, Great Ormond Street. London WCI N 3JH
P.A. RICH M. KRAAYENBRINK
References [I] CAMPKIN TV, FLYNNRM. Isoflurane and cerebrospinal fluid
pressure-a study in neurosurgical patients undergoing intracranial shunt proceedures. Anaesrhesia 1989; 44: 5 0 4 . [2] MCPHERSON RW, JOHNSON RM, TRAYTSMAN RJ.The effects of alfentanil on the cerebral vasculature. Anes1hesiolog.v 1982; 57: 354-5. [3] FRAGEN RJ, BOOIJLHDJ, BRAAKGJJ, VREETB, HEYKANTS J, CRULJF. Pharmacokinetics of the infusion of alfentanil in man Brirish Journal of Anaesthesia 1983; 55: 1077-81.
Caudal anaesthesia in the Shy-Drager syndrome We wish to report the successful use of caudal anaesthesia in a patient with the Shy-Drager syndrome which consists of progressive autonomic failure and multiple system atrophy [I]. A search of the literature has not revealed a previous report. A 55-year-old man (height 1.79 m weight 84.5 kg) with Shy-Drager syndrome presented for cystoscopy. He gave a 6-year history of increasing difficulty in emptying the bladder with frequency and dribbling causing great distress. Other symptoms were loss of libido, impotence, progressive weakness of the left side of the body and Parkinsonism. Cystoscopy under topical anaesthesia had been abandoned due to inadequate analgesia. The patient had previously undergone several operations under general anaesthesia. These included exploratory laminectomy and extirpation of the ligamentum flavum at the L,-L, level; implantation of a Scott penis prosthesis, and elongation of the tendon of the left big toe. Since the last operation 18 months earlier, his condition had deteriorated. Relevant findings on examination were difficulty in swallowing with accumulation of saliva; shallow breathing with weakness of the respiratory muscles and coarse crepitations over both lung fields; inability to cough effectively and breathlessness on gentle exertion. Pulse rate was 70 beat.min-' and blood pressure 200/110 mmHg, but readings varied with posture. Caudal anaesthesia was considered appropriate. Premedication was with diazepam 10 mg orally 1 h before surgery. Pulse and blood pressure were monitored throughout and an intravenous infusion of 2.5% dextrose with sodium 70 mmol.1-' (Ringerdex) commenced. A
caudal block was performed and 0.5% bupivicaine 20 ml and 2% mepivacaine 10 ml with adrenaline 5 pg.ml-l injected. The level of analgesia was confirmed as T,,-L, using an ethyl chloride spray. During the first 20 min after injection of the local anaesthetics, systolic blood pressure decreased from 240 to 220 mmHg, and the pulse rate rose from 70 to 80 beat.min-'. The patient was placed in the lithotomy position and this was followed by a rise in systolic pressure to 240 mmHg. As he found the position uncomfortable, diazepam 10 mg were given intravenously. Cystoscopy was then performed. O n returning the legs to the horizontal, systolic pressure decreased to 210 mmHg although the pulse rate remained steady at 75-80 beat.min- '. Postoperative recovery was uneventful. In the Shy-Drager syndrome autonomic reflexes are defective resulting in an 'auto-sympathectomised' state. Regional blockade is thus likely to have only minimal effects on arterial blood pressure and this was illustrated by our patient. East Surrey Hospital, Three Arch Road, Redhill RHI 5RH Sandivken Hospital Authority, S-81 I 89. Sweden
M. MONTELL
Reference [I] SHYGM, DRAGERGA. A neurological syndrome associated with orthostatic hypotension. A clinical-pathological study. Archives of Neurology 1960; 2 5 I 1-27.
Nutricath insertion-a We wish to draw your attention to a hazard involving the insertion of a Vygon Nutricath ' S . A 63-year-old woman presented for replacement of a prosthetic aortic valve. A 16-G Nutricath 'S' 2180.17 was in situ in the right subclavian vein. It had been used for
F.A.R. GOMESZ
hazard
4 weeks to administer antibiotics for treating an episode
of subacute bacterial endocarditis. On removing the Nutricath, it was noted that 6 cm of stylet protruded from the end of the catheter. (Fig. 1) Review of the chest X-ray taken immediately after catheter insertion revealed that the
Correspondence
1 101
bacterial growth and emboli. The rigid stylet might increase the risks of vessel wall erosion. In conclusion, it is essential for the operator to familiarise him/herself with the manufacturers’ instructions and the contents of the equipment about to be used. Careful review of the postinsertion chest X ray would have revealed the stylet. University Hospital of Wales, Cardiff CF4 4XW
K. BARCLAY
R. FALCONER P. LATTO
A reply
Fig. 1.
protruding stylet was visible. Comparison with a new Nutricath ‘s’showed that the stylet was complete and that it had separated at the point of connection with the hub used for withdrawing the stylet. We were surprised to find that it was possible to inject fluid without undue difficulty down the catheter with the stylet in place. The hub and stylet may not have been joined at manufacture. Alternatively the hub and stylet may have been weakly joined and when separated the operator failed to appreciate that the stylet remained in the catheter. The manufacturers’ instructions specify that the stylet should be withdrawn an equivalent amount for every 5 cm of the catheter advanced. It is difficult to remove the stylet once the catheter is fully inserted and this may result in breakage. Only four of 20 Vygon Nutricath ‘S’ catheters examined in this hospital came with enclosed instructions. Complications associated with leaving the stylet in situ include: embolus o f the stylet; clot formation o n the stylet,
Thank you for the opportunity to comment on this unique incident. We fully endorse the authors’ conclusion that operators must familiarise themselves with the Instructions For Use (IFU) of any medical device. In addition we would recommend that anyone attempting the insertion of a tunnelled catheter of this type would d o so initially under supervision of an experienced operator. Examination of the product reveals no evidence of a manufacturing defect. The history of the incident supports breakage of the stylet through user error. The observation that comprehensive IFU are present in only four of the catheter sets is a result of updated IFU being introduced to this product range in mid 1990. Prior to this only limited instructions were included. Should anyone require additional copies we are able to supply them through Mrs Hazel Selby in our Customer Services Department o n 0285 657051. An instructional video is also available on loan. Product Development Manager, Vygon ( U K ) Ltd, Cirencester GL7 IPT
Equipment deadspace in paediatric breathing systems I am writing to remind anaesthetists of a potential hazard regarding the use of nonpaediatric equipment in children. As receiving anaesthetist I took over the care of a child whose lungs were being ventilated through a T-piece and Jackson Rees modification. The system contained additional deadspace due to the inclusion of a disposable catheter mount and an adult sized condenser humidifier filter, inserted between the tracheal tube and the breathing system (Fig. I). The child was a 6-year-old boy who was transferred paralysed and his lungs ventilated because of a head injury, which had resulted in three grand-ma1 fits followed by an unrousable state. He weighed approximately 25 kg and therefore his estimated anatomical deadspace would be 52.5 ml (7 x 25 x 30%). However, as his trachea was intubated this figure would be too high an estimate and could probably be halved. The measured equipment deadspace was 59 ml for the condenser humidifier and 27 ml for the catheter mount. Thus the total functional deadspace was 112.25 ml (52.5/2+59+27)or 213.8% ofthatexpectedina child with an alveolar deadspace of 122.5 ml (7 x 25 x 70%). The resultant blood gases at 6 I.min-I of oxygen were pH 7.122; PCO, 11.45; kPa P0,62.35; kPa HCO, 28.0; mmol.l-’; B.E. -4.3 mmol.1-I. Twenty minutes after the extraneous parts of the system had been removed, with ventilation being continued a t 6 Lmin-’, they were: pH 7.452, Pco, 3.93 kPa, PO, 71.5 kPa, HCO, 20.5 mmol.1-’, B.E. - 1.3 mmol.1-I.
Fig. 1.
R.J. PANRUCKER
Correspondence
A 66-year-old man with a 9 month history of headaches followed by left sided arm and facial weakness, presented for craniotomy, motor cortical mapping and excision of tumour. He was otherwise healthy. Following premedication with glycopyrronium 0.2 mg I h preoperatively, anaesthesia was induced with thiopentone 5 mg.kg-l followed by vecuronium 0.1 mg.kg-l. Alfentanil 1 .O mg was administered prior to tracheal intubation and anaesthesia was maintained with isoflurane 0.5% and nitrous oxide with 35% oxygen. An alfentanil infusion was commenced at 0.5 mg.kg-'.h-l and no further relaxant was required until the motor cortical mapping was completed. The expired CO, concentration was maintained at 3.5% using a Cape Waine ventilator. Prior to motor cortical mapping we tested for residual neuromuscular blockade using a peripheral nerve stimulator, which demonstrated a train-of-four ratio of 1 and the absence of tetanic fade. Movement of the patient's hand during cortical stimulation confirmed recovery of neuromuscular transmission. When the cortical mapping was completed the patient was reparalysed with vecuronium and the alfentanil infusion rate was halved initially and discontinued 30 min prior to reversal. Good operating conditions were achieved and the patient woke up quickly at the end of surgery and was alert during recovery.
Our use of alfentanil allowed ventilation of the lungs without neuromuscular blockade and without the risk of moving o r coughing, while avoiding the problems of deep inhalational anaesthesia. Alfentanil does not increase cerebral blood flow [2] and because of its pharmacokinetic profile, recovery is rapid following discontinuation of the infusion [3]. These features make it ideal for intracranial surgery. This use of alfentanil has not been described before for this purpose and we feel it has much to recommend it in this type of case. Hospitals for Sick Children, Great Ormond Street. London WCI N 3JH
P.A. RICH M. KRAAYENBRINK
References [I] CAMPKIN TV, FLYNNRM. Isoflurane and cerebrospinal fluid
pressure-a study in neurosurgical patients undergoing intracranial shunt proceedures. Anaesrhesia 1989; 44: 5 0 4 . [2] MCPHERSON RW, JOHNSON RM, TRAYTSMAN RJ.The effects of alfentanil on the cerebral vasculature. Anes1hesiolog.v 1982; 57: 354-5. [3] FRAGEN RJ, BOOIJLHDJ, BRAAKGJJ, VREETB, HEYKANTS J, CRULJF. Pharmacokinetics of the infusion of alfentanil in man Brirish Journal of Anaesthesia 1983; 55: 1077-81.
Caudal anaesthesia in the Shy-Drager syndrome We wish to report the successful use of caudal anaesthesia in a patient with the Shy-Drager syndrome which consists of progressive autonomic failure and multiple system atrophy [I]. A search of the literature has not revealed a previous report. A 55-year-old man (height 1.79 m weight 84.5 kg) with Shy-Drager syndrome presented for cystoscopy. He gave a 6-year history of increasing difficulty in emptying the bladder with frequency and dribbling causing great distress. Other symptoms were loss of libido, impotence, progressive weakness of the left side of the body and Parkinsonism. Cystoscopy under topical anaesthesia had been abandoned due to inadequate analgesia. The patient had previously undergone several operations under general anaesthesia. These included exploratory laminectomy and extirpation of the ligamentum flavum at the L,-L, level; implantation of a Scott penis prosthesis, and elongation of the tendon of the left big toe. Since the last operation 18 months earlier, his condition had deteriorated. Relevant findings on examination were difficulty in swallowing with accumulation of saliva; shallow breathing with weakness of the respiratory muscles and coarse crepitations over both lung fields; inability to cough effectively and breathlessness on gentle exertion. Pulse rate was 70 beat.min-' and blood pressure 200/110 mmHg, but readings varied with posture. Caudal anaesthesia was considered appropriate. Premedication was with diazepam 10 mg orally 1 h before surgery. Pulse and blood pressure were monitored throughout and an intravenous infusion of 2.5% dextrose with sodium 70 mmol.1-' (Ringerdex) commenced. A
caudal block was performed and 0.5% bupivicaine 20 ml and 2% mepivacaine 10 ml with adrenaline 5 pg.ml-l injected. The level of analgesia was confirmed as T,,-L, using an ethyl chloride spray. During the first 20 min after injection of the local anaesthetics, systolic blood pressure decreased from 240 to 220 mmHg, and the pulse rate rose from 70 to 80 beat.min-'. The patient was placed in the lithotomy position and this was followed by a rise in systolic pressure to 240 mmHg. As he found the position uncomfortable, diazepam 10 mg were given intravenously. Cystoscopy was then performed. O n returning the legs to the horizontal, systolic pressure decreased to 210 mmHg although the pulse rate remained steady at 75-80 beat.min- '. Postoperative recovery was uneventful. In the Shy-Drager syndrome autonomic reflexes are defective resulting in an 'auto-sympathectomised' state. Regional blockade is thus likely to have only minimal effects on arterial blood pressure and this was illustrated by our patient. East Surrey Hospital, Three Arch Road, Redhill RHI 5RH Sandivken Hospital Authority, S-81 I 89. Sweden
M. MONTELL
Reference [I] SHYGM, DRAGERGA. A neurological syndrome associated with orthostatic hypotension. A clinical-pathological study. Archives of Neurology 1960; 2 5 I 1-27.
Nutricath insertion-a We wish to draw your attention to a hazard involving the insertion of a Vygon Nutricath ' S . A 63-year-old woman presented for replacement of a prosthetic aortic valve. A 16-G Nutricath 'S' 2180.17 was in situ in the right subclavian vein. It had been used for
F.A.R. GOMESZ
hazard
4 weeks to administer antibiotics for treating an episode
of subacute bacterial endocarditis. On removing the Nutricath, it was noted that 6 cm of stylet protruded from the end of the catheter. (Fig. 1) Review of the chest X-ray taken immediately after catheter insertion revealed that the
Correspondence
1 101
bacterial growth and emboli. The rigid stylet might increase the risks of vessel wall erosion. In conclusion, it is essential for the operator to familiarise him/herself with the manufacturers’ instructions and the contents of the equipment about to be used. Careful review of the postinsertion chest X ray would have revealed the stylet. University Hospital of Wales, Cardiff CF4 4XW
K. BARCLAY
R. FALCONER P. LATTO
A reply
Fig. 1.
protruding stylet was visible. Comparison with a new Nutricath ‘s’showed that the stylet was complete and that it had separated at the point of connection with the hub used for withdrawing the stylet. We were surprised to find that it was possible to inject fluid without undue difficulty down the catheter with the stylet in place. The hub and stylet may not have been joined at manufacture. Alternatively the hub and stylet may have been weakly joined and when separated the operator failed to appreciate that the stylet remained in the catheter. The manufacturers’ instructions specify that the stylet should be withdrawn an equivalent amount for every 5 cm of the catheter advanced. It is difficult to remove the stylet once the catheter is fully inserted and this may result in breakage. Only four of 20 Vygon Nutricath ‘S’ catheters examined in this hospital came with enclosed instructions. Complications associated with leaving the stylet in situ include: embolus o f the stylet; clot formation o n the stylet,
Thank you for the opportunity to comment on this unique incident. We fully endorse the authors’ conclusion that operators must familiarise themselves with the Instructions For Use (IFU) of any medical device. In addition we would recommend that anyone attempting the insertion of a tunnelled catheter of this type would d o so initially under supervision of an experienced operator. Examination of the product reveals no evidence of a manufacturing defect. The history of the incident supports breakage of the stylet through user error. The observation that comprehensive IFU are present in only four of the catheter sets is a result of updated IFU being introduced to this product range in mid 1990. Prior to this only limited instructions were included. Should anyone require additional copies we are able to supply them through Mrs Hazel Selby in our Customer Services Department o n 0285 657051. An instructional video is also available on loan. Product Development Manager, Vygon ( U K ) Ltd, Cirencester GL7 IPT
Equipment deadspace in paediatric breathing systems I am writing to remind anaesthetists of a potential hazard regarding the use of nonpaediatric equipment in children. As receiving anaesthetist I took over the care of a child whose lungs were being ventilated through a T-piece and Jackson Rees modification. The system contained additional deadspace due to the inclusion of a disposable catheter mount and an adult sized condenser humidifier filter, inserted between the tracheal tube and the breathing system (Fig. I). The child was a 6-year-old boy who was transferred paralysed and his lungs ventilated because of a head injury, which had resulted in three grand-ma1 fits followed by an unrousable state. He weighed approximately 25 kg and therefore his estimated anatomical deadspace would be 52.5 ml (7 x 25 x 30%). However, as his trachea was intubated this figure would be too high an estimate and could probably be halved. The measured equipment deadspace was 59 ml for the condenser humidifier and 27 ml for the catheter mount. Thus the total functional deadspace was 112.25 ml (52.5/2+59+27)or 213.8% ofthatexpectedina child with an alveolar deadspace of 122.5 ml (7 x 25 x 70%). The resultant blood gases at 6 I.min-I of oxygen were pH 7.122; PCO, 11.45; kPa P0,62.35; kPa HCO, 28.0; mmol.l-’; B.E. -4.3 mmol.1-I. Twenty minutes after the extraneous parts of the system had been removed, with ventilation being continued a t 6 Lmin-’, they were: pH 7.452, Pco, 3.93 kPa, PO, 71.5 kPa, HCO, 20.5 mmol.1-’, B.E. - 1.3 mmol.1-I.
Fig. 1.
R.J. PANRUCKER
