In Reply:‐We thank the Drs. Bevan for their kind remarks, and we agree with most of their comments. However, their final conclusions regarding cost considerations are probably premature. As noted in our Table 2, the times to the first train‐of‐four (TOF) measurement in the postanesthesia care unit (PACU) for pancuronium (30.0 min) versus mivacurium (19.7 min) required an asterisk. [1
] These intervals represent whichever came first, the initial TOF value noted in the PACU or the time until the TOF ratio reached a value of 0.90 (as measured in the operating room [OR]). Thus, 52 of 56 patients who received pancuronium had neuromuscular monitoring that continued into the PACU. Only 15 of the 35 patients who received mivacurium required such follow‐up evaluation. Consequently, it probably is not correct to assume that 10 min of OR time was “saved” with the mivacurium group.
If the average clinical anesthetist was routinely able to accurately quantitate residual block and defer discharge from the OR until satisfactory recovery of neuromuscular function (TOF greater or equal to 0.70) was present, then we suspect that short‐ to intermediate‐acting relaxants would provide real savings in OR recovery time. Unfortunately, subjective evaluation of the extent of TOF fade is notoriously imprecise. Once the TOF ratio exceeds a ratio of 0.40, most clinicians are unable to detect that any fade exists. [2,3
] In the “real world” as Bevan's data [4
] nicely demonstrate, after antagonism of pancuronium‐induced neuromuscular blockade, 15 min is insufficient time to guarantee satisfactory return of neuromuscular function.
Aaron F. Kopman, M.D.; Jennifer Ng, M.D.; Lee M. Zank, M.D.; George G. Neuman, M.D.; Pamela S. Yee, M.D.
Department of Anesthesiology; St. Vincents Hospital and Medical Center
153 West 11th Street; New York, NY 10011
(Accepted for publication February 5, 1997.)
1. Kopman AF, Ng J, Zank LM, Neuman GG, Yee PS: Residual postoperative paralysis: Pancuronium versus mivacurium, does it matter. Anesthesiology 1996; 85:1253-9.
2. Viby-Mogensen J, Jensen NH, Engbaek J, Ording H, Skovgaard LT, Chraemmer-Jorgensen B: Tactile and visual evaluation of the response to train-of-four stimulation. Anesthesiology 1985; 63:440-3.
3. Kopman AF, Mallhi MU, Justo MD, Rodricks P, Neuman GG: Antagonism of mivacurium-induced neuromuscular blockade in humans. Edrophonium dose requirements at threshold train-of-four count of 4. Anesthesiology 1994; 1394-400.
4. Bevan DR, Smith CE, Donati F: Postoperative neuromuscular blockade: a comparison between atracurium, vecuronium, and pancuronium. Anesthesiology 1988; 69:272-6.
© 1997 American Society of Anesthesiologists, Inc.