Preferences of Mexican anesthesiologists for vecuronium, rocuronium, or other neuromuscular blocking agents: a survey

BMC Anesthesiology 2BR2M0e0Cs2eA,naerscthhesiaolrotgiycle x Preferences of Mexican anesthesiologists for vecuronium, rocuronium, or other neuromuscular blocking agents: a survey A A Nava-Ocampo 2 J C Ramrez-Mora 1 D Moyao-Garca 1 J Garduo- Espinosa 0 J Salmern 3 0 Division of Medical Informatics, Coordinacion de Investigacion en Salud , IMSS , Mexico 1 Department of Anesthesia and Respiratory Therapy, Hospital Infantil de Mexico "Federico Gomez" , SSa , Mexico 2 Unit of Medical Research in Pharmacology, Hospital de Especialidades, Centro Medico Nacional "Siglo XXI" , IMSS , Mexico 3 Epidemiology and Health Services Research Unit, Hospital General Regional No. 1, IMSS, Cuernavaca, Morelos , Mexico Background: Several neuromuscular blocking (NMB) agents are available for clinical use in anesthesia. The present study was performed in order to identify preferences and behaviors of anesthesiologists for using vecuronium, rocuronium or other NMB agents in their clinical practice. Material and methods: The cross-sectional survey was applied at the Updated Course of the Colegio Mexicano de Anestesiologa performed last year. Of 989, 282 (28.5%) surveys were returned. Results: Most anesthesiologists were working at both public and private hospitals, performed anesthetic procedures for hospitalized and ambulatory patients, and anesthetized children as well as adults. Respondents did not consider mechanomyography as the gold standard method for neuromuscular monitoring. The T25 was not recognized as a pharmacodynamic parameter that represents the clinical duration of the neuromuscular block. Most answered that vecuronium induces less histamine release than rocuronium, had never used any neuromuscular monitor, did not know the cost of vecuronium and rocuronium, and preferred rocuronium in multiple-sampling vials and vecuronium in either a vial for single or multiple sampling. Rocuronium was preferred for emergency surgery in patients with full stomach only. Almost all of anesthesiologists that conserve the unused drug did it without refrigeration and more than 30% conserve the unused drug in one syringe for further use. Conclusion: Vecuronium was preferred for most clinical situations, and the decision for this choice was not based on costs. Storage of unused drugs without refrigeration in a single syringe for purpose of future use in several patients represented a dangerous common practice. - Background Neuromuscular blockade is an important component of most procedures that require general anesthesia to facilitate tracheal intubation and the surgical procedure. Nondepolarizing neuromuscular blocking (NMB) agents are usually preferred because of fewer adverse effects than depolarizing drugs [13]. According to their chemical structure, two classes of non-depolarizing NMB agents have been available for clinical use, the aminosteroidal (pancuronium, vecuronium and rocuronium) and benzylisoquinoline drugs (atracurium, mivacurium and cisatracurium). Vecuronium has been used for many years in the clinical setting whereas rocuronium is available in Mexico only since 1999 [4]. Rocuronium has a faster onset of action than vecuronium [5,6], and its metabolites by lacking pharmacological effects avoid any residual neuromuscular block [7]. These characteristics favor rocuronium as a better alternative than vecuronium. In relation to the benzilisoquinoline drugs, these type of NMB agents produce cardiovascular response and clinical evidence of histamine release even at recommended doses [8,9]. In our country, until 2000 rocuronium was only provided as an ampoule containing 50 mg/5 mL, and since last year the pharmaceutical presentation was modified to a vial containing a similar concentration but allowing multiple sampling. Whereas vecuronium is available in two pharmaceutical presentations, a single-sampling ampoule and a vial allowing multiple sampling. Each of the two presentations has only 4 mg of vecuronium. It is estimated that 1.4 million of surgical procedures were performed last year at the IMSS [10], and three million of surgical procedures are being performed every year by the Mexican public health care systems [11]. According to cost obtained from different sources, rocuronium is significantly more expensive than vecuronium, therefore, a complete replacement of vecuronium by rocuronium could result into a significant increase in spending. The present survey was performed in order to identify the preferences of anesthesiologists, as primary users, in relation to the use of rocuronium, vecuronium or other NMB agents. Material and Methods The survey, printed in the two sides of one letter-size sheet of paper, was developed and validated by a group of four board-certified Mexican anesthesiologists and two epidemiologists. It was attached to the documents given to the 989 persons inscribed to the Annual Course of the Colegio Mexicano de Anestesiologa (formerly the Sociedad Mexicana de Anestesiologa) performed in July, last year. Conference participants were encouraged to fill out and return the survey at the end of each conference day during the three days of the course. Of 989, 282 (28.5%) surveys were returned. Data from returned surveys was captured in a predesigned Microsoft 97Excel form and reported as the number of respondents and proportions. In some cases, numbers could vary according to persons answering any specific question. The survey included the following four sections: Section 1: General information. 1) Your current maximal specialty training is: anesthesiologist, anesthesiologist with subspecialty training, or anesthesiology resident. 2) Have you been practicing anesthesia for < 5, 5 to 10, or >10 years? 3) Have you been working at a public, private or both types of health services? 4) Are your anesthetic procedures performed in pediatric, adults, or mixed patients? If mixed patients was selected, then the proportion representing the pediatric patients was asked (<25, 25 to 50, 50 to 75 or >75%). 5) Are your anesthetic procedures performed on ambula tory, hospitalized or mixed patients? If a mixed setting was selected, then the proportion representing the ambulatory patients was asked (<25, 25 to 50, 50 to 75 or >75%). Section 2: Basic questions on neuromuscular relaxation. Questions were elaborated with information obtained from different sources including textbooks [1,12], printed documents obtained by subscription [13], guidelines [14] and web-sites [15]. All sources were available in Spanish language, at any medical library or freely accessed on the Internet. 6) Neuromuscular relaxants are classified according to: chemical structure, duration of action, action at the neuromuscular junction or you do not know. 7) The pharmacodynamic parameter of T25 represents: the time to loss the muscular tone, the time to maximal block, the clinical duration of the neuromuscular block, or you do not know. 8) Which of the following methods is considered as the gold (...truncated)