To the Editor:—
The recent article 1
and editorial 2
regarding acceleromyography findings of residual paralysis hours after neuromuscular blockade (NMB) raised several questions and proposed sweeping conclusions based on results found in extubated patients on arrival in the PACU, transferred by competent anesthesiologists. The type of anesthesia and the time from discontinuation is unknown. No patient was examined prior to use of NMB for preexistent abnormalities, and it does not appear that any of the study patients required or were given reversal agents, despite the “findings” of residual NMB. I suspect that all recovered successfully and without complaint, making the relevance of “acceleromyographic quantification of residual effects” clinically irrelevant. The editorial invokes “evidence-based practice,” but the “evidence” lies outside the realm of practice. Evidence should have clinical consequence. The newest mantra of medicine was ignored:outcome-based
. Also, because the study was not randomized and double-blind, it may be too soon to make these sweeping recommendations.
Universal reversal is offered as if no adverse effects are associated with such drugs: Hypersalivation, nausea, asystole, bradycardia and tachycardia, laryngospasm, negative pressure pulmonary edema and failure to reverse or recognize such, prolonged apnea after succinylcholine for reintubation, and so forth are potential reversal side effects. These acceleromyographic findings are extremely difficult/impossible to quantify, using the clinically commonplace mechanomyogram tactile and visual methods. 3
Increased utilization of complex monitoring devices is also proposed, as if no shortcomings are introduced—don’t forget the costs and time involved in applying/acquiring devices and to verifying/failing to verify complete reversal! No scientific test will ever replace the clinical ability to comprehensively evaluate the patient’s ability to breathe and maintain an airway or clinical experience to appreciate pharmacodynamics in medicine. Recovery
is a composite of dissipation of the clinical effects of all
anesthetic agents, as well as the imposition of the surgical events: Indeed, frequently patients remain intubated because of surgical trespass, narcotics, sedatives, or preoperative/perioperative infirmity.
How many study patients with residual NMB needed reversal, were reversed, or failed recovery without reversal, and based on what criteria? Did the residual effects disappear after reversal agents, and when? How did age, core temperature, body mass index, NMB agent used, and patient satisfaction correlate to the findings of individual’s residual NMB hours after a single dose? Did the abdominal wound inhibit head lift in your patients, as it does in mine, and how did you control for this? How is this study clinically relevant: what were the outcomes? A great deal of neuromuscular and pharmacokinetic reserve is evident in many healthy, muscular patients yet not evident in debilitated geriatric patients, who will need complete reversal. Do we need pharmacologic reversal in every patient and can these tests actually measure clinical reversal in ALL patients? Are we recommending obligate reversal to eliminate acceleromyograph findings or clinical respiratory compromise, and what side effects will obligate reversal and acceleromyograph monitoring incur? Sometimes the enemy of “good” is “better.”
Paul M. Kempen, M.D., Ph.D.
1. Debaene B, Plaud B, Dilly, M-P, Donati F: Residual paralysis in the PACU after a single intubating dose of nondepolarizing muscle relaxant with an intermediate duration of action. A nesthesiology 2003; 98: 1042–8
2. Eriksson LI: Evidence-based practice and neuromuscular monitoring: It’s time for routine quantitative assessment. A nesthesiology 2003; 98: 1037–9
3. Dorsch JA, Dorsch SE: Vigilance aids and monitors, Understanding Anesthesia Equipment, 3rd edition, Baltimore, Williams and Wilkins, 1994, pp 609–92
© 2004 American Society of Anesthesiologists, Inc.