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Alfentanil and rocuronium during rapid-sequence induction of anaesthesia
- tom heier (3 July 2007)
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Opioids and rapid-sequence induction
- Mohammad El-Orbany (20 June 2007)
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tom heier, professor of Anesthesia Dept of Anesthesia, Aker University Hospital, Oslo, Norway
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Dear Editor,we appreciate Dr El-Orbany´s response to our paper. While we agree that the effect of rocuronium was not at it´s peak when the tracheal intubation was performed in our study, we still think that the effect of this drug contributed significantly to optimize the intubation conditions. This assumption is based on results from previous studies for ex by Wright (1) and Andrews (2). In the latter publication rocuronium 1.0 mg/kg was superior to 0.6 mg/kg with respect to intubation conditions. It is also correctly addressed by Dr. El-Orbany that waiting 60 s (instead of 40 s i our study) before laryngoscopy probably would have reduced the need for alfentanil to obtain perfect intubation conditions. However, even if no study has shown that the morbidity or mortality rate is different when intubation is performed 60 or 90 s after commencement of anesthesia induction, we believe that most anesthesiologists prefer to secure the airway as early as possible after the drug administration in a rapid-sequence situation. Waiting more than 40 s after administration of the muscle relaxant will also require artificial ventilation before tracheal intubation in a significant number of patients. We therefore think that the design used in our study, ie performing tracheal intubation 40 s post rocuronium administration, is closely imaging the clinical needs during rapid-sequence induction of anesthesia. References: Wright PMC, Caldwell JE, Miller RD: Onset and duration of rocuronium and succinylcholine at the adductor pollicis and laryngeal adductor muscles in anesthetized humans. Anesthesiology 1994:81:1110-1115 Andrews JI,kumar N, Van Don Brom RHG et al. A large simple randomized trial of rocuronium versus succinylecholine in rapid-sequence induction of anaesthesia along with propofol. Acta Anaesiol Scan 1999;43:4-8 No conflict of interest exists for any of the authors. Mohammad H Abou-Arab, MD, Research Fellow Aker University Hospital, Oslo, Norway Tom Heier, MD, PhD, Professor of Anesthesia Department of Anesthesia, Aker University Hospital, Oslo, Norway James E Caldwell, MB, ChB, Professor of Anesthesia Department of Anesthesia and Perioperative Care, University of California, UCSF, San Francisco, USA Conflict of Interest:None declared |
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Mohammad El-Orbany
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Editor, I read with interest the article about the dose of alfentanil needed during the course of rapid sequence induction (RSI) with thiopentone and rocuronium(1). Obtaining optimal conditions at the time of tracheal intubation is one of the major goals and prerequisites for a successful rapid sequence induction/intubation technique. If the tracheal intubation conditions are poor during the attempted intubation, this can lead to a failed RSI and turn it into a very slow induction with all the risks that the technique was originally undertaken to prevent. Choice of the drugs to be used, proper timing of their administration as well as proper timing of tracheal intubation are of paramount importance for the technique to be successful. There is no doubt that prior administration of a fast acting opioid like alfentanil or remifentanil in adequate doses will lead to improved intubation conditions during RSI(2). We must commend the authors for trying to find the right dose of alfentanil that can result in optimal tracheal intubation conditions. While the choice of alfentanil and timing of its administration were successful, the timing of tracheal intubation (40 seconds after rocuronium administration) was too early for the full effect of rocuronium to be established. Using mechanomyography, the onset of rocuronium neuromuscular block after a 1.2 mg kg -1 dose was found to be 54 s at the laryngeal adductors and 65 s at the adductor pollicis(3). May be what the authors were really testing are the intubation conditions resulting only from opioid and induction drug administration. Tracheal intubation without the use of muscle relaxant can result in satisfactory intubation conditions in 93% of the patients(4), but this should not be tried for RSI because we should give the technique all the chances to be successfully completed. What was wrong with waiting 20 more seconds for the intubation attempt to be performed? This could have allowed the muscle relaxant to establish its effects and could have resulted in even better intubation conditions. On the other hand, there is no evidence that there is an increased incidence of aspiration or desaturation as long as tracheal intubation is accomplished within 90 seconds. Most importantly, waiting this extra 20 seconds can dramatically decrease the incidence of a failed RSI with all of its potential risks. Had the authors considered intubation at 60 seconds, could this have changed the dose of alfentanil required to produce optimal conditions at the new time of intubation? and if the new recommended dose was found to be less than the optimal dose that was required for a 40s intubation, could this have resulted in a decrease in the incidence of hypotension (20%) that was associated with alfentanil/thiopentone administration? This may need further investigation. Mohammad El-Orbany, M.D. Department of Anesthesiology Medical College of Wisconsin Milwaukee, WI References : 1- Abou-arab MH, Heier T, Caldwell JE. Dose of Alfentanil needed to obtain optimal intubation conditions during rapid-sequence induction of anaesthesia with thiopentone and rocuronium. Br J Anaesth 2007;98: 604-10 2- Lavazais S, Debaene B.Choice of the hypnotic and the opioid for rapid-sequence induction. Eur J Anaesthesiol Suppl. 2001;23:66-70. 3- Wright PM, Caldwell JE, Miller RD. Onset and duration of rocuronium and Succinylcholine at the adductor pollicis and laryngeal adductor muscles in anesthetized humans. Anesthesiology. 1994;81:1110-5 4- Klemola UM, Mennander S, Saarnivaara L. Tracheal intubation without the use of muscle relaxants: remifentanil or alfentanil in combination with propofol. Acta Anesthesiol Scand 2000;44:465-9 Conflict of Interest:None declared |
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