Residual Neuromuscular Blockade
Residual neuromuscular block is perhaps most accurately defined as the presence of signs or symptoms of muscle weakness in the postoperative period after the intraoperative administration of an NMBD.
Muscle relaxants have revolutionized anesthesiology, and are routinely used to:
- improve intubating conditions
- decrease the risk of patients´laryngeal and vocal cord trauma
- optimize surgical conditions
- facilitate mechanical ventilation
Incomplete recovery from paralysis at the time of extubation is a patient safety risk.
Every year millions of patients are affected by postoperative respiratory complications. In US alone, more than 100.000 patients annually are at risk of adverse events associated with undetected residual neuromuscular blockade. Clinical studies show that residual neuromuscular block at the end of anesthesia increases the incidence of critical respiratory events. The currently accepted definition for “adequate recovery” from neuromuscular block is the return of the train-of-four (TOF) ratio to, or above 0.9 (90%). It has been shown that this level of recovery restores the most of the functional integrity of the muscles involved in airway protection, but even at this level of recovery, the normal response to hypercarbia (carbon dioxide retention) is blunted. The basic principle for preventing residual neuromuscular block is quantitative neuromuscular monitoring.
Why Monitor Neuromuscular Blockade?
When NMT monitoring is absent, inadequate, or inaccurate, there is an increased risk of:
- pulmonary aspiration
- airway obstruction
- adverse respiratory events (hypoxia, atelectatis, pneumonia, etc)
- pharyngeal dysfunction
- prolonged post anesthesia stays
- unpleasant postoperative symptoms including muscle weakness
Monitoring the effects of neuromuscular blocking drugs ensures their appropriate intra-operative use and helps prevent residual neuromuscular weakness.
The avoidable clinical challenge- Prevent the Preventable
Murphy GS, Brull SJ. Residual neuromuscular block: lessons unlearned. Part I: definitions, incidence, and adverse physiologic effects of residual neuromuscular block. Anesth Analg. 2010;111(1):120‐128
Murphy GS et al. Residual neuromuscular blockade and critical respiratory events in the postanesthesia care unit. Anesth Analg 2008; 107:130-7
Bissinger et al. Postoperative residual paralysis and respiratory status:a comparative study of pancuronium and vecuronium. Physiol Res 2000;49:455-62
Berg H et al. Residual neuromuscular block is a risk factor for postoperative pulmonary complications. A prospective , randomized, and blinded study of postoperative pulmonar complications after atracurium, vecuronium and pancuronium. Acta Anaesthesiol Scand 1997;41:1095-103.
Butterly A et al, Postoperative Residual Curarization from inter-mediate acting neuromuscular blocking agents delays recovery from discharge. BR J Aneast; 2010 Sep; 105(3):304-9
Martinez-Ubieto J et al, Prospective study of residual neuromuscular block and postoperative respiratory complications in patients reversed with neostigmine vs sugammadex. Minerva Anesthesiol. 2016;82(7):735-742
Brull SJ, Naguib M, Miller RD. Residual neuromuscular Block; rediscovering the obvious. Anesth Analg. 2008; 107:11-14
Saager L, Maiese EM, Bash LD, et al. Incidence, risk factors and consequences of residual neuromuscular block in the United States: The prospective, observational, multicenter RECITE-US study. J Clin Anesth. 2019;55:33-41
Niederman MS et al. The cost of treating Community-Acquired Pneumonia. Clin Ther.1998;20:820-37