Sugammadex Reversal of Profound Vecuronium Block
A Critical Appraisal of Quantitative Research
The purpose of this specific study is to compare the neuromuscular block reversal rates and effects for sugammadex, a selective relaxant binding agent, with neostigmine. In many types of surgery, there appears to be a benefit for the patient to be kept in a state of profound relaxation throughout the entire procedure. Anesthesiologists are usually hindered in this goal through the surgery in its entirety because of the inability of standard agents to rapidly reverse such profound neuromuscular block. This forces anesthesiologists to restrict the level of neuromuscular block near the end of surgery (Lemmens, El-Orbany, Berry & Martin, 2010). Since sugammadex has the potential to decrease the time necessary to reduce neuromuscular block, there is an opportunity for it to aid anesthesiologists by allowing them to extend the duration of the profound relaxation later into a procedure.
This study was built around the framework that sugammadex has been shown to successfully reverse rocuronium induced profound blocks to a train of four ration of .9 relatively quickly. The concept of interest here, then, is whether or not these properties of sugammadex can translate into faster block reversals when using vecuronium, which is more potent than rocuronium (Lemmens, El-Orbany, Berry & Martin, 2010). Furthermore, the conceptual interest includes the existence of any serious adverse effects in doing so. The sample size was ninety-four patients spread randomly across eight centers in the United States. Originally it was planned that fifty-two patients receive sugammadex and the rest receive neostigmine. The population consisted of adults with American Society of Anesthesiologist (ASA) class I-IV receiving general endotracheal anesthesia for elective surgery requiring neuromuscular blockade both for induction and maintenance. They were further limited to general surgery in the supine position. Patients were excluded if they had a neuromuscular condition, history of malignant hyperthermia, significant renal dysfunction, an allergy to narcotics, muscle relaxants or other medications used during general anesthesia. Exclusions also included pregnant and breastfeeding women and women who were of childbearing age and not under adequate birth control. The sample size was further reduced when it was determined by the data and safety board discontinued the neostigmine group due to the marked difference in efficacy. There was also one instance of a patient receiving rocuronium instead of vecuronium. The final sample size was forty-six patients receiving sugammadex and thirty-six receiving neostigmine.
The sample size does appear to be representative of the general population in terms that it was conducted throughout the United States and that the population was more female. There were several biases in the sampling method, in terms of limiting the patient population in terms of comorbidities, allergies, and limiting the procedures to general elective surgery. Another bias was the limitation of only using vecuronium and sevoflurane.
This was a phase III safety-assessor blinded study across several different institutions utilizing the same procedures. The procedure was to place Train-of-Four (TOF) monitor on the arm at the ulnar nerve with a transducer affixed to the volar aspect of the distal phalanx of the thumb. This was placed on the arm that contained the intravenous line for drug delivery and calibrated in the operating room. The TOF was to have repetitive stimulation every fifteen seconds at the ulnar nerve until the end of anesthesia or at least until the TOF ratio was 0.9. There were no variables actively defined in the article except to point out that the same procedure was used to minimize variability. This being there is variability because TOF interpretation is very subjective. In this study the attending...
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