NEUROMUSCULAR BLOCKADE (GS MURPHY, SECTION EDITOR)
Should Neuromuscular Blockade Be Routinely Reversed?
Published online: 14 April 2018
Springer Science+Business Media, LLC, part of Springer Nature 2018
Purpose of review The purpose of this article is to present the consequences and incidence of residual paralysis and define
solutions to reduce the risk of its occurrence.
Recent findings Small degrees of residual paralysis, defined as a train-of-four (TOF) ratio < 0.9, may increase the risk of
postoperative respiratory complications and influence outcomes following surgery. Routine monitoring of neuromuscular block
can allow the detection of incomplete neuromuscular recovery and is an important factor in the prevention of residual paralysis.
Administration of neostigmine or sugammadex to reverse residual paralysis should be based on the degree of spontaneous
recovery. Sugammadex acts much faster than neostigmine and can even reverse deep levels of neuromuscular blockade.
Summary Meticulous management of neuromuscular blockade, including routine reversal of the effects of muscle relaxants, is
essential in avoiding residual block and associated complications.
Keywords Residual paralysis
Neuromuscular blocking agents
Despite important advances in knowledge relating to dosing,
monitoring, and reversal of neuromuscular blockade, the rou-
tine use of reversal agents remains debated. Meanwhile, the
incidence and the occurrence of respiratory complications dur-
ing residual paralysis remain highly underestimated. In 2010,
most respondents from the USA (64.1%) and Europe (52.2%)
considered the incidence of clinically significant postoperative
residual neuromuscular weakness to be < 1% . However,
the clinician should be aware that the lingering effects of neu-
romuscular blockade may last well beyond surgery and can
have significant clinical consequences.
Does Residual Paralysis Exist?
Every physician should understand that neuromuscular
blocking agents (NMBAs) do not have the same effect on all
muscles of the body. The diaphragm and the abdominal wall
muscles are among the more resistant muscles to NMBA;
thus, recovery from neuromuscular block is significantly
faster at these respiratory muscles than at the adductor pollicis.
Studies have demonstrated that tidal volume can be preserved
even at a train-of-four count of 0. Initially, a train-of-four
(TOF) ratio of 0.7 at the adductor pollicis was considered a
safe threshold assuring recovery from neuromuscular block
because ventilation had returned to control values obtained
before administration of a NMBA. This belief was supported
by a study from Berg et al. who were able to demonstrate that
during pancuronium-induced neuromuscular blockade, pa-
tients with a TOF ratio less than 0.7 had milder or even severe
episodes of desaturation in the PACU and were more likely to
develop postoperative pulmonary complications . As a con-
sequence, some clinicians still consider that routine reversal
from neuromuscular block, before extubation of the patient, is
unnecessary when tidal volume and minute ventilation have
recovered to normal values.
Nevertheless, respiratory function depends on more than
adequate recovery of the diaphragm.
This article is part of the Topical Collection on Neuromuscular Blockade
* Claude Meistelman
Department of Anesthesiology, Hopital Maisonneuve-Rosemont,
Université de Montréal, 5415 Boulevard de l’Assomption,
Montréal, QC H1T 2M4, Canada
Department of Anesthesiology and Intensive Care Medicine, Hopital
de Brabois, Université de Lorraine, rue du Morvan,
54500 Vandoeuvre, France
Current Anesthesiology Reports (2018) 8:150–156