Despite better recovery of neuromuscular function after sugammadex compared to neostigmine, some patients are still partially paralyzed in the PACU. (Image source: Thinkstock)
Despite better recovery of neuromuscular function after sugammadex compared to neostigmine, some patients are still partially paralyzed in the PACU. (Image source: Thinkstock)

Most anesthesia providers in this country, and in Japan, do not monitor neuromuscular function despite evidence that quantitative neuromuscular monitoring is associated with a lower risk of morbidity, including muscle weakness, critical respiratory events and length of PACU stay. Pity the patient who wakes up feeling weak after surgery because the anesthesia provider is unwilling to spend a few extra dollars or yen.  We pay so much attention to PONV, but patients are probably just as dismayed about feeling weak after surgery.

Would postoperative weakness be less if sugammadex rather than neostigmine were used, even without the use of intraoperative neuromuscular function monitoring?  In the study “Reversal with Sugammadex in the Absence of Monitoring Did Not Preclude Residual Neuromuscular Block,” Dr. Yoshifumi Kotake, Department of Anesthesiology and Perioperative Care, Toho University Ohashi Medical Center, Ohashi, Meguro, Tokyo, Japan, and colleagues examined postoperative residual weakness in the PACU after the use of either sugammadex or neostigmine at the end of surgery.

There were about 100 patients in each group.  The patients in the neostigmine group were studied between October 2009 and February 2010, and patients in the sugammadex group were studied between November 2010 and March 2011.  Patients received either sevoflurane or propofol for maintenance of anesthesia.  Rocuronium was used for paralysis.  The anesthesiologist caring for the patient determined the neostigmine dose.  Patients in the sugammadex group received 2 mg/kg of the drug if patients bucked, breathed spontaneously or moved an extremity or 4 mg/kg if there were no signs of such activity.  In the PACU, accelerographic response of the adductor pollicis muscle to a 50-mA train-of-four stimulation was measured.

The incidence of a train-of-four ratio less than 0.9 was 24% in the neostigmine group and 4% after sugammadex; incidence of a train-of-four ratio less than 1 was 67% in the neostigmine group and 46% in the sugammadex group.  Use of sevoflurane in the neostigmine reversal group was associated with more residual muscle weakness; in the sugammadex group, the longer the interval between administration of the last dose of rocuronium and measurement of train-of-four ratio was associated with a lower incidence of train-of-four ratio < 1.

Even with use of sugammadex, without the use of intraoperative neuromuscular function monitoring, some patients in the PACU have residual weakness.  This study did not compare patients at similar times, type of anesthesia was not standardized, and neither type nor length of surgery was standardized.  Also, more sugammadex could have been used. Finally, it’s not clear what type of surgery patients underwent and whether paralysis was actually needed.

As noted by Drs. Mohamed Naguib (Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio;), Sorin J. Brull (Department of General Anesthesia, Mayo Clinic College of Medicine, Jacksonville, Florida) and Hal R. Arkes (Department of Psychology, The Ohio State University, Columbus, Ohio) in the accompanying editorial “Reasoning of an Anomaly: Residual Block After Sugammadex,” given the current cost of sugammadex, 6 doses of the drug could more than pay for a nerve stimulator.  More to the point: “Physicians have been trained to ‘do no harm,’ which is consistent with the willingness of practitioners to eschew any harmful therapy. But, are we not potentially imposing harm on our patients by not monitoring the adequacy of recovery from neuromuscular blocking drugs?

It may well be that until and unless every clinician personally experiences a complication in a patient as a result of residual neuromuscular block, the ‘benefit’ of changing routine practice to perioperative objective monitoring will not be appreciated. Are we doomed to repeat history?”