Published in:
01-06-2018 | Neuromuscular Blockade (GS Murphy, Section Editor)
Neostigmine: Mechanism of Action, Dosing, and Factors Determining Adequacy of Recovery Following Administration
Published in: Current Anesthesiology Reports | Issue 2/2018
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Purpose of Review
The endpoint of adequate neuromuscular recovery allowing for safe extubation has been revised several times. A train-of-four (TOF) ratio of at least 0.9 measured at the adductor polices muscle is required to exclude clinically relevant residual paralysis. In particular, upper airway muscle integrity, the hypoxic ventilatory response, and swallowing are still impaired at shallow degrees of residual paralysis. The aim of this review is to evaluate the efficacy of neostigmine in achieving this higher benchmark.
Recent Findings
Recent findings suggest that (a) the administration of neostigmine should be delayed until advanced degrees of pre-reversal recovery have occurred (i.e., T1 > 25% or the fourth response to TOF stimulation), or recovery intervals over 15 min have to be accepted; (b) small concentrations of neostigmine (i.e., 20–30 μg/kg) are effective in antagonizing shallow degrees of residual paralysis; and (c) the appropriate administration of neostigmine (i.e., dosing based on monitoring) reduces postoperative complications and improves neuromuscular recovery.
Summary
When 40–70 μg/kg neostigmine are administered at the return of 1–4 TOF responses, a recovery interval over 20 min can be expected. Increasing the dose of neostigmine will not further accelerate this interval, but it may increase the risk of paradoxical effects (i.e., the reappearance of fade). A shorter recovery interval is obtained when neostigmine-based reversal is given at more advanced spontaneous pre-reversal neuromuscular recovery.