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Letters to the Editor: Letter to the Editor

Residual Neuromuscular Block Should, and Can, Be a “Never Event”

El-Orbany, Mohammad MD; Ali, Hassan H. MD, MA (Hons); Baraka, Anis MD, FRCA (Hon); Salem, M. Ramez MD

Author Information
doi: 10.1213/ANE.0000000000000090
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To the Editor:

In their recent study, Murphy et al.1 reported about one-third of patients arrived to the postanesthesia care unit (PACU) with a train-of-four ratio (TOFR) <0.9; however, this is not a new finding. In their classic article investigating the causes of death associated with anesthesia and surgery, Beecher and Todd2 described increased mortality in patients receiving curare as “curare deaths.” Although they did not specifically attribute the increased mortality to residual neuromuscular block (RNMB), it seems inescapable that, in fact, Beecher and Todd2 were describing one of the earliest outcome studies, drawing attention to postoperative RNMB. In the late 1970s, Viby-Mogensen et al.3found the incidence of patients arriving to the PACU with a TOFR <0.7 to be 42%. The incidence of RNMB has, since then, been persistently high despite the use of intermediate duration neuromuscular blockers.4 Addressing this long-neglected problem should be a priority safety concern because it may lead to serious clinical consequences in the PACU.1

We therefore urge universal adoption of objective (quantitative) monitoring of neuromuscular transmission as a standard guiding tracheal extubation (TE) decision.5,6 It is ironic that RNMB is defined in terms of a TOFR, but TE is still performed without a device that measures and displays the TOFR.

We also recommend that both clinical and evoked responses to different patterns of nerve stimulation (not only TOFR) should be used to ascertain adequate neuromuscular recovery before TE.6,7 Unfortunately, a wide discrepancy exists currently between anesthesiologists’ perception of the occurrence of the problem and the actual incidence of >30%. In a recent survey, 80% of the respondents reported that they never encountered a single clinically significant RNMB, and 60% thought the incidence to be <1%.8 Obviously, this false perception needs to be addressed, and practitioners should become more aware of the problem.

In view of the multiple accumulating reports, including that by Murphy et al.,1 demonstrating the persisting high incidence of RNMB, we ask all anesthesia societies (national and international) to urgently create practice guidelines/standards governing the clinical management and monitoring of neuromuscular blockade. Until such guidelines are published and implemented, the incidence of adverse events related to RNMB in the PACU will continue to surpass all other PACU anesthetic-related morbidities.

A new culture of considering RNMB as one of the “never events”9 should prevail, and anesthesia societies should encourage practitioners to achieve a goal of zero incidents.

Mohammad El-Orbany, MD

Department of Anesthesiology

Medical College of Wisconsin

Milwaukee, Wisconsin

[email protected]

Hassan H. Ali, MD, MA (Hons)

Department of Anesthesiology

Harvard Medical School at Massachusetts General Hospital

Boston, Massachusetts

Anis Baraka, MD, FRCA (Hon)

Department of Anesthesiology

American University of Beirut

Beirut, Lebanon

M. Ramez Salem, MD

Department of Anesthesiology

Advocate Illinois Masonic Medical Center

Chicago, Illinois


1. Murphy GS, Szokol JW, Avram MJ, Greenberg SB, Shear T, Vender JS, Gray J, Landry E. Postoperative residual neuromuscular blockade is associated with impaired clinical recovery. Anesth Analg. 2013;117:133–41
2. Beecher HK, Todd DP. A study of the deaths associated with anesthesia and surgery: based on a study of 599, 548 anesthesias in ten institutions 1948-1952, inclusive. Ann Surg. 1954;140:2–35
3. Viby-Mogensen J, Jørgensen BC, Ording H. Residual curarization in the recovery room. Anesthesiology. 1979;50:539–41
4. Hayes AH, Mirakhur RK, Breslin DS, Reid JE, McCourt KC. Postoperative residual block after intermediate-acting neuromuscular blocking drugs. Anaesthesia. 2001;56:312–8
5. El-Orbany M. Objective monitoring of neuromuscular block should become the standard of care. Acta Anaesthesiol Scand. 2009;53:837
6. Baraka A. “Neostigmine-resistant curarization”. Middle East J Anesthesiol. 2013;22:131–4
7. Ali HH. Criteria of adequate clinical recovery from neuromuscular block. Anesthesiology. 2003;98:1278–80
8. Naguib M, Kopman AF, Lien CA, Hunter JM, Lopez A, Brull SJ. A survey of current management of neuromuscular block in the United States and Europe. Anesth Analg. 2010;111:110–9
9. Green J, Butterworth J. “Never” events: anesthesiology’s dirty little secret. Anesth Analg. 2013;117:1–2
© 2014 International Anesthesia Research Society