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Rocuronium for Caesarean section
British Journal of Anaesthesia
348 range of 4 to 7 mg/kg." The dose we used in our study was within that range. Second, in our study, 17.5 % had an Apgar score of less than 7 at 1 min, and all were ^ 7 at 5 min. The results were not worse than those in the article quoted by Kwan, Chen and Liao and showed Apgar scores of 6 or less in 24.7% of nconates [2]. Moreover, in our study, the umbilical venous and arterial bloodgas tensions and acid-base values, which are more indicative of fetal depression man Apgar scores, were normal (e.g. umbilical venous and arterial pH values were 7.3 and 7.29, respectively). We also found no correlation between the neuroadaptive capacity scores, a more refined technique than Apgar scores, and thiopentone dose. We feel that, irrespective of the neuromuscular blocker used, every effort should be made to optimize the inrubating conditions as the most common cause of maternal death from anaesthesia is failure to inrubate the trachea. If this is provided by increasing the dose of thiopentone from 4 to 6 mg kg~', so be it. In respect of textbook recommendations of the dose of thiopentone, we suggest that these should be reconsidered on the basis of our study, especially when a neuromuscular blocker other than suxamcthonium is used or difficulty in intubation is encountered. E. ABOULEISH T. ABBOOD
Sir,—We read with interest the article by Abouleish and colleagues [1]. However, we are unhappy with the conclusion that the combination of thcopentone 6 mg kg"1 and rocuronium 0.6 mg kg"1 is a safe choice for rapid sequence induction for Caesarean section. While 90 % of the patients in their study had good to excellent inrubating conditions, this represents only one criterion for choosing a neuromuscular blocker for rapid sequence induction. Failed intubation occurs in at least 1 in 300 obstetric general anaesthetics. In the vast majority of these situations the delivery is not urgent and the mother is allowed to regain consciousness. If immediate delivery is essential, many obstetric anaesthetists advise continuing anaesthesia with face mask ventilation until spontaneous ventilation returns. Rocuronium 0.6 mg kg"1 has a duration of action of 30 min, which in the event of failed intubation requires continued mask ventilation encouraging gastric distension and a heightened risk of aspiration. The ideal neuromuscular blocking agent is one with a rapid onset but also a rapid offset, notably suxamethonium. M. MCSWINBY C. EDWARDS A. WILKINS
Department of Anaesthetics Southampton General Hospital Southampton 1. Abouleish E, Abboud T, Lechevalier T, Zhu J, Chalian A, Alford K. Rocuronium (Org 9426) for Caesarean section. British Journal of Anaesthesia 1994; 73: 336-341. Sir,—Abouleish and colleagues [1] described the use of rocuronium (Org 9426) in 40 elective Caesarean section patients at full term without fetal distress. They concluded that its use "was found to be safe for mother and fetus". We believe that this conclusion needs some qualification. Rocuronium is not the first non-depolarizing neuromuscular blocker to be used for rapid sequence induction of anaesthesia for Caesarean section. Vecuronium in a priming dose regimen [2] has been described as an alternative drug, although the onset time and clinical duration were found to be longer than desired. The authors were careful to state that vecuronium should be considered only when suxamethonium is contraindicated.
H. A. SWALES D. G. GAYLARD
Department of Anaesthesia Royal Perth Hospital Perth, WA 1. Abouleish E, Abboud T, Lechevalier T, Zhu A, Chalian A, Alford K. Rocuronium (Org 9426) for Caesarean section. British Journal of Anaesthesia 1994; 73: 336-341. 2. Hawkins JL, Johnson TD, Kubieck MA, Skjonsby BS, Morrow DH, Joyce TH in. Vecuronium for rapid-sequence intubation for cesarean section. Anesthesia and Analgesia 1990; 71: 185-190. 3. Hewett E, Livingstone P. Management of failed endotracheal intubation at caesarean section. Anaesthesia and Intensive Care 1990; 18: 330-335. 4. Davies JM, Weeks S, Crone LA. Failed intubation at caesarean section. Anaesthesia and Intensive Care 1991; 19: 303. 5. Mallampati RS, Gatt SP, Gugino LD, Desai SP, Waraksa B, Freiberger D, Liu PL. A clinical sign to predict difficult tracheal intubation: a prospective study. Canadian Anaesthetists Society Journal 1985; 32: 429-^34. 6. Samsoon GLT, Young JRB. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987; 42: 487-490. 7. Williams KN, Carli F, Cormack RS. Unexpected, difficult laryngoscopy: a prospective survey in routine general surgery. British Journal of Anaesthesia 1991; 66: 38-44. 8. O'Leary J, Williams AE. Failed intubation at caesarean section—a reply. Anaesthesia and Intensive Care 1990; 18: 590.
Sir,—We absolutely agree with McSwiney, Edwards and Wilkins and Swales and Gaylard that suxamethonium is the drug of choice for Caesarean section. The reasons arc not only its short duration of action as they mentioned, but also the provision of ideal inrubating conditions and the absence of neonatal effects, except in the presence of abnormal cholinesterase [1]. Suxamethonium has withstood the test of time. The intention of our study was not to compare rocuronium with suxamethonium, and we did not do that. Our conclusion was not to advocate replacing suxamethonium by rocuronium, and we did not state that. However, as mentioned in the introduction of our article, the use of suxamethonium may be inadvisable in certain conditions, for example susceptibility to malignant hyperthermia, abnormal cholinesterase genotypes and susceptibility to hyperkalaemia. Under these conditions, other neuromuscular blockcrs should be considered. Of those available, the one with the shortest onset of action is rocuronium, thus ensuring control of the airway in the minimum time following loss of consciousness. E. ABOULEISH T. ABBOUD
Department of Anaesthesiology University of Texas Medical School at Houston Houston, Texas, USA 1. Baraks A, Haroun S, Bassili M, Abu-Haider G. Response of the newborn to succinylcholine injection in hermizygote atypical mothers. Anesthesiology 1975; 43: 115-116.
Downloaded from http://bja.oxfordjournals.org/ by guest on March 26, 2015
Department of Anesthesiology University of Texas Medical School at Houston Houston, Texas, USA 1. Kosaka Y, Takahashi T, Mark LC. Intravenous thiobarbiturate anesthesia for cesarean section. Anesthesiology 1969; 31: 489-506. 2. Finster M, Poppers PJ. Safety of thiopental used for the induction of general anesthesia in elective cesarean section. Anesthesiology 1968; 29: 190-191.
Rocuronium has a faster onset time than vecuroniumj and appears to be a more suitable alternative to suxamethonium, indeed, there were no serious problems in the 40 patients described. Most obstetric anaesthetists have a "failed intubation drill". This usually includes (particularly in the case of elective Cacsarcan section) recourse to allowing the patient to waken after attempts at intubation have failed [3, 4]. This course of action is precluded by the use of rocuronium. Despite various methods of assessment (e.g. Mallampati [5]), difficult intubation may not be predicted [6] and the incidence of failed intubation is reported to be higher in the obstetric, than in the general surgical, population [7]. The importance of allowing spontaneous ventilation after failed intubation has been stressed by some authors [8]. We suggest that the substitution of rocuronium for suxamethonium cannot be supported unless there are specific contraindications to suxamethonium. The use of rocuronium necessitates a preplanned modification of the failed intubation drill.
348 range of 4 to 7 mg/kg." The dose we used in our study was within that range. Second, in our study, 17.5 % had an Apgar score of less than 7 at 1 min, and all were ^ 7 at 5 min. The results were not worse than those in the article quoted by Kwan, Chen and Liao and showed Apgar scores of 6 or less in 24.7% of nconates [2]. Moreover, in our study, the umbilical venous and arterial bloodgas tensions and acid-base values, which are more indicative of fetal depression man Apgar scores, were normal (e.g. umbilical venous and arterial pH values were 7.3 and 7.29, respectively). We also found no correlation between the neuroadaptive capacity scores, a more refined technique than Apgar scores, and thiopentone dose. We feel that, irrespective of the neuromuscular blocker used, every effort should be made to optimize the inrubating conditions as the most common cause of maternal death from anaesthesia is failure to inrubate the trachea. If this is provided by increasing the dose of thiopentone from 4 to 6 mg kg~', so be it. In respect of textbook recommendations of the dose of thiopentone, we suggest that these should be reconsidered on the basis of our study, especially when a neuromuscular blocker other than suxamcthonium is used or difficulty in intubation is encountered. E. ABOULEISH T. ABBOOD
Sir,—We read with interest the article by Abouleish and colleagues [1]. However, we are unhappy with the conclusion that the combination of thcopentone 6 mg kg"1 and rocuronium 0.6 mg kg"1 is a safe choice for rapid sequence induction for Caesarean section. While 90 % of the patients in their study had good to excellent inrubating conditions, this represents only one criterion for choosing a neuromuscular blocker for rapid sequence induction. Failed intubation occurs in at least 1 in 300 obstetric general anaesthetics. In the vast majority of these situations the delivery is not urgent and the mother is allowed to regain consciousness. If immediate delivery is essential, many obstetric anaesthetists advise continuing anaesthesia with face mask ventilation until spontaneous ventilation returns. Rocuronium 0.6 mg kg"1 has a duration of action of 30 min, which in the event of failed intubation requires continued mask ventilation encouraging gastric distension and a heightened risk of aspiration. The ideal neuromuscular blocking agent is one with a rapid onset but also a rapid offset, notably suxamethonium. M. MCSWINBY C. EDWARDS A. WILKINS
Department of Anaesthetics Southampton General Hospital Southampton 1. Abouleish E, Abboud T, Lechevalier T, Zhu J, Chalian A, Alford K. Rocuronium (Org 9426) for Caesarean section. British Journal of Anaesthesia 1994; 73: 336-341. Sir,—Abouleish and colleagues [1] described the use of rocuronium (Org 9426) in 40 elective Caesarean section patients at full term without fetal distress. They concluded that its use "was found to be safe for mother and fetus". We believe that this conclusion needs some qualification. Rocuronium is not the first non-depolarizing neuromuscular blocker to be used for rapid sequence induction of anaesthesia for Caesarean section. Vecuronium in a priming dose regimen [2] has been described as an alternative drug, although the onset time and clinical duration were found to be longer than desired. The authors were careful to state that vecuronium should be considered only when suxamethonium is contraindicated.
H. A. SWALES D. G. GAYLARD
Department of Anaesthesia Royal Perth Hospital Perth, WA 1. Abouleish E, Abboud T, Lechevalier T, Zhu A, Chalian A, Alford K. Rocuronium (Org 9426) for Caesarean section. British Journal of Anaesthesia 1994; 73: 336-341. 2. Hawkins JL, Johnson TD, Kubieck MA, Skjonsby BS, Morrow DH, Joyce TH in. Vecuronium for rapid-sequence intubation for cesarean section. Anesthesia and Analgesia 1990; 71: 185-190. 3. Hewett E, Livingstone P. Management of failed endotracheal intubation at caesarean section. Anaesthesia and Intensive Care 1990; 18: 330-335. 4. Davies JM, Weeks S, Crone LA. Failed intubation at caesarean section. Anaesthesia and Intensive Care 1991; 19: 303. 5. Mallampati RS, Gatt SP, Gugino LD, Desai SP, Waraksa B, Freiberger D, Liu PL. A clinical sign to predict difficult tracheal intubation: a prospective study. Canadian Anaesthetists Society Journal 1985; 32: 429-^34. 6. Samsoon GLT, Young JRB. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987; 42: 487-490. 7. Williams KN, Carli F, Cormack RS. Unexpected, difficult laryngoscopy: a prospective survey in routine general surgery. British Journal of Anaesthesia 1991; 66: 38-44. 8. O'Leary J, Williams AE. Failed intubation at caesarean section—a reply. Anaesthesia and Intensive Care 1990; 18: 590.
Sir,—We absolutely agree with McSwiney, Edwards and Wilkins and Swales and Gaylard that suxamethonium is the drug of choice for Caesarean section. The reasons arc not only its short duration of action as they mentioned, but also the provision of ideal inrubating conditions and the absence of neonatal effects, except in the presence of abnormal cholinesterase [1]. Suxamethonium has withstood the test of time. The intention of our study was not to compare rocuronium with suxamethonium, and we did not do that. Our conclusion was not to advocate replacing suxamethonium by rocuronium, and we did not state that. However, as mentioned in the introduction of our article, the use of suxamethonium may be inadvisable in certain conditions, for example susceptibility to malignant hyperthermia, abnormal cholinesterase genotypes and susceptibility to hyperkalaemia. Under these conditions, other neuromuscular blockcrs should be considered. Of those available, the one with the shortest onset of action is rocuronium, thus ensuring control of the airway in the minimum time following loss of consciousness. E. ABOULEISH T. ABBOUD
Department of Anaesthesiology University of Texas Medical School at Houston Houston, Texas, USA 1. Baraks A, Haroun S, Bassili M, Abu-Haider G. Response of the newborn to succinylcholine injection in hermizygote atypical mothers. Anesthesiology 1975; 43: 115-116.
Downloaded from http://bja.oxfordjournals.org/ by guest on March 26, 2015
Department of Anesthesiology University of Texas Medical School at Houston Houston, Texas, USA 1. Kosaka Y, Takahashi T, Mark LC. Intravenous thiobarbiturate anesthesia for cesarean section. Anesthesiology 1969; 31: 489-506. 2. Finster M, Poppers PJ. Safety of thiopental used for the induction of general anesthesia in elective cesarean section. Anesthesiology 1968; 29: 190-191.
Rocuronium has a faster onset time than vecuroniumj and appears to be a more suitable alternative to suxamethonium, indeed, there were no serious problems in the 40 patients described. Most obstetric anaesthetists have a "failed intubation drill". This usually includes (particularly in the case of elective Cacsarcan section) recourse to allowing the patient to waken after attempts at intubation have failed [3, 4]. This course of action is precluded by the use of rocuronium. Despite various methods of assessment (e.g. Mallampati [5]), difficult intubation may not be predicted [6] and the incidence of failed intubation is reported to be higher in the obstetric, than in the general surgical, population [7]. The importance of allowing spontaneous ventilation after failed intubation has been stressed by some authors [8]. We suggest that the substitution of rocuronium for suxamethonium cannot be supported unless there are specific contraindications to suxamethonium. The use of rocuronium necessitates a preplanned modification of the failed intubation drill.