Kopman AF, Kopman DJ, Ng J, Zank LM. Antagonism of profound cisatracurium and rocuronium block: The role of objective assessment of neuromuscular function
ABSTRACT The purpose of this study is to determine the incidence of significant (train-of-four [TOF] ratio <0.70), but clinically undetectable (TOF ratio >0.40), residual neuromuscular block after neostigmine antagonism of profound cisatracurium (CIS) or rocuronium (ROC) block.
Prospective, randomized, open-label study.
Forty ASA physical status I and II undergoing elective surgical procedures.
Anesthesia was induced with propofol 1.5 to 2.5 mg/kg IV plus fentanyl 2 to 4 mug/kg and maintained with N(2)O/desflurane plus narcotic supplementation. The electromyographic response of the adductor pollicis was recorded. Train-of-four stimulation was given every 20 seconds. Twitch height (T1) and TOF fade ratio were continuously recorded. In group 1 (n = 20), neuromuscular block was induced with CIS 0.10 mg/kg, and T1 was maintained at 5% of control by a constant infusion of CIS until the end of surgery. One minute after the termination of the infusion, neostigmine 0.05 mg/kg was administered. T1 and TOF values were monitored continuously for the next 20 minutes. Group 2 (n = 20) is identical to group 1 except that the initial drug was ROC 0.60 mg/kg, and paralysis was maintained with an infusion of ROC.
There were no significant differences in the recovery patterns of CIS vs ROC. The duration (bolus to end of infusion) in both groups averaged 2.7 hours, and the mean cumulative dose of relaxant approximated 4 x the ED(95). T1 at the time of reversal was 6% (4%-10%) of control. Mean TOF ratios at 10, 15, and 20 minutes were 0.55, 0.71, and 0.0.81, respectively. Return to a TOF ratio >0.40 was always achieved in 15 minutes or less. However, at 20 minutes postreversal, 5 of 40 subjects had TOF ratios <0.70 and only 11 individuals had recovered to a TOF ratio of 0.90 or greater.
Most clinicians cannot detect tactile fade once the TOF ratio exceeds 0.40. When reversing profound block, an objective monitor of neuromuscular function is required if the extent of residual block is to be assessed with any confidence.
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ABSTRACT: The perioperative use of neuromuscular blocking agents has revolutionized medicine, and has allowed numerous and significant advances in the surgical management of patients. However, surgical advancement has not been devoid of attendant complications such as intraoperative patient recall, residual neuromuscular weakness, pulmonary aspiration of gastric contents, and need for tracheal reintubation. This chapter briefly reviews the various ways in which clinicians can optimize the timing and dosing of muscle relaxants, improve perioperative monitoring of muscle relaxation, and enhance the pharmacologic reversal of neuromuscular block. These strategies are intended to reduce the incidence of postoperative neuromuscular weakness and improve the safety of patients undergoing surgery and general anesthesia.06/2013; 3(2). DOI:10.1007/s40140-013-0014-9
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ABSTRACT: Satisfactory recovery from nondepolarizing neuromuscular block is currently defined as return of the train-of-four ratio at the adductor pollicis muscle to a value of 0.90 or greater. Studies in volunteers demonstrate that train-of-four ratios of 0.70–0.80 are associated not only with subjective symptoms of weakness, but also dysfunction of the muscles of airway patency and swallowing. There is ample evidence that a sizeable proportion of patients who receive nondepolarizing neuromuscular blocking agents return to postanesthesia care units with undetected postoperative residual neuromuscular block (postoperative muscle weakness). However, until recently, outcome studies that demonstrate that postoperative weakness may be associated with adverse patient outcomes have been lacking. This review is an attempt to collate the available data that suggest that even modest levels of residual block have untoward clinical consequences.06/2013; 3(2). DOI:10.1007/s40140-013-0009-6
- International Anesthesiology Clinics 02/2006; 44(2):77-90. DOI:10.1097/00004311-200604420-00005