Inadequate neuromuscular blockade common during surgery
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This suggests that "more effective strategies to prevent and/or manage residual neuromuscular blockade are required to minimize the impact on the patient and health care provider," she said.
The incidence of postoperative residual neuromuscular blockade was 19% for patients with a TOF ratio less than 0.6 at tracheal extubation, 12% with a ratio of 0.6-0.7, 9% with a ratio of 0.7-0.8, 16% with a ratio of 0.8-0.9, and 44% with a ratio of 0.9 or greater. The incidence of residual blockade was 8% for patients with a TOF ratio less than 0.6 upon arrival to the PACU, 7% with a ratio of 0.6-0.7, 14% with a ratio of 0.7-0.8, 16% with a ratio of 0.8-0.9, and 56% with a ratio of 0.9 or greater.
In the United States, neostigmine, an acetylcholinesterase inhibitor, is the most common means of reversing neuromuscular blocking agents, according to Scott Devine, Ph.D., of Merck. Giving neostigmine too early can be ineffective, and giving it too late might induce skeletal muscle weakness.
He and his associates analyzed data from the Anesthesia Quality Institute’s National Anesthesia Clinical Outcomes Registry (NACOR) on 113,276 procedures utilizing rocuronium or vecuronium that were reversed with neostigmine in 2010-2012. The reversal agent was given a mean of 63 minutes after the last dose of a neuromuscular blocking agent, 7 minutes before surgical site closure, 14 minutes prior to emergence, and 29 minutes before the end of anesthesia time, though each administration time had a wide range, he reported.
A substantial number of patients would have spontaneously recovered from the effects of the neuromuscular blockers after 63 minutes, suggesting that neostigmine often may be given later than needed, he said. If neostigmine is given 7 minutes before surgical site closure, reversal of neuromuscular blockade could be well underway, resulting in increased muscle tension during surgical site closure, which could increase the risk of complications such as dehiscence or postsurgical hernias, he added.
The large variability in practice may be due to multiple factors and deserves further research, he said.
Merck, which markets a neuromuscular blockade agent, sponsored the studies and supplied at least one investigator for each study.
sboschert@frontlinemedcom.com On Twitter @sherryboschert
