Monitoring Neuromuscular Blockade Often Overlooked

Aaron F. Kopman, MD

To the Editor

I am not a constant reader of the APSF Newsletter so perhaps I’ve missed the APSF’s position on this topic; nevertheless, I think it represents a subject worthy of APSF attention. As a supposed “authority” on the clinical use of neuromuscular blocking agents (NMBA), I still come across clinicians who opine, “I haven’t used a peripheral nerve stimulator (PNS) in 20 years and I see no reason to start now.” On a recent visit to a well respected academic medical center, the anesthesiologist in charge of pediatric anesthesia told me that he never uses PNS units since they “don’t work in kids.”

While a recent editorial opinion (Anesthesiology 2003;98:1037-9) certainly does not support these ideas, I am unaware of any published clinical guidelines by organizations such as the APSF or the ASA on the subject. I think the time has come for these societies to clearly state that the administration of nondepolarizing relaxants in the absence of neuromuscular monitoring represents substandard care.

In a letter to a correspondent, I noted in part. . .

“I agree that there are only limited outcome data (Acta Anaesthesiol Scand 1997;41:1095-1103) to suggest that patients who arrive in the PACU with TOF ratios of 0.50, for example, have a significantly increased morbidity or mortality compared to individuals who have attained a TOF ratio > 0.80. To prove this thesis would require a rather massive project that is not likely to be funded. However, anesthesiology as a specialty has been lauded for the drop in anesthesia risk, which has been documented over the last 20 years. Improvements in monitoring have been cited as a major determinant of this perceived improvement in outcome. Nevertheless, there is little evidence-based data that clearly show that pulse oximetry or capnography in fact reduces overall morbidity. Yes, anecdotal reports abound, but the same can be said for the use of objective neuromuscular monitoring.

“When I was a resident (over 40 years ago) we did not have or routinely use electrocardiography, pulse oximetry, capnography, anesthetic agent monitors, or cerebral-function physiologic monitors. Nor did we miss them. Now I would feel naked without them. Do I use the TOF-Watch or the Datex M-NMT module in every case where nondepolarizing blocking drugs are administered? No. However, I sincerely believe that this monitoring modality should be routinely available to the anesthesiologist. My experience suggests that it is a great pedagogical tool. What it teaches is that clinical judgment is often wrong.”

Aaron F. Kopman, MD
New York, NY