20 July 2025 : Review article
Advances in Neuromuscular Monitoring Techniques in Anesthesiology: A 2025 Perspective
Łukasz Grabarczyk
ABDEF 1*
DOI: 10.12659/MSM.948980
Med Sci Monit 2025; 31:e948980
Table 1 Neuromuscular blockade monitoring in special use populations.
| Population | Pharmacokinetics and pharmacodynamics | Choice of muscle relaxants | Use of reversal agents | Monitoring neuromuscular function |
|---|---|---|---|---|
| Pregnant women []34 | Increased plasma volume [up to 45%] → decrease in plasma protein levels → binding of drugs rocuronium or pancuronium to plasma proteins decreased → increased concentration of the free, active form.A 50–60% increase in glomerular filtration rate with hepatic blood flow unchanged → altered drug concentrations in the blood | Rocuronium: fast onset of action (about 25%) and a prolonged duration of action during pregnancy; not associated with malignant hyperthermia, hyperkalemia, or vagal blockade, does not increase intracranial or intraocular pressure.Vecuronium: weak placental penetration; prolonged duration during pregnancy and the puerperium; minimal impact on the cardiovascular system | Sugammadex is an effective agent for reversing rocuronium | Continuous and quantitative neuromuscular monitoring required |
| Renal impairment []36 | Prolonged elimination of muscle relaxants due to reduced kidney function → prolonged drug action → increased risk of accumulation → dosage adjustments and careful monitoring required | Choose cisatracurium and atracurium which undergo Hofmann elimination (a non-renal pathway) | Renal impairment affects the clearance of certain reversal agents, such as neostigmine. Consider sugammadex (used safely in patients with varying degrees of renal function, with caution and dosing adjustments) []76 | Enhanced monitoring – preferably AMG on adductor pollicis muscle |
| Neuromuscular diseases []37 | Increased sensitivity to these agents | Non-depolarizing muscle relaxants should be used at reduced doses | Standard doses may be insufficient or excessive, depending on the patient’s condition and the muscle relaxant used | detailed evaluation of the patient’s neuromuscular status, respiratory function, and cardiac health (function tests); continuous monitoring using quantitative devices; Extended observation in a setting equipped to manage potential respiratory complications |
| Hepatic diseases []38 | Decreased protein synthesis → lower plasma protein binding → increased free fraction of the drug → enhanced therapeutic effects. Impaired hepatic metabolism and biliary excretion → prolonged half-life → drug accumulation → prolonged neuromuscular blockade | Cisatracurium preferred due to predictable metabolism via Hofmann elimination and ester hydrolysis; rocuronium may exhibit reduced clearance and prolonged action | Sugammadex, primarily excreted unchanged by the kidneys, is a potentially safer option in patients with hepatic dysfunction [].Safety and efficacy of traditional anticholinesterases (eg, neostigmine) may be altered76 | Liver dysfunction may alter the metabolism of neuromuscular blocking agents and reversal agents, necessitating vigilant monitoring to ensure patient safety |
| Acid-base balance impairments []39 | Decreased pH increases potency of non-depolarizing muscle relaxants resulting in prolonged duration of action. Increased pH reduces the effectiveness of these agents, necessitating higher doses to achieve the desired neuromuscular blockade | Agents less sensitive to pH variations, such as cisatracurium, are preferred | Acidosis can diminish the effectiveness of anticholinesterase agents like neostigmine, potentially leading to inadequate reversal of neuromuscular blockade. Adjust dosing or consider alternative reversal strategies | Continuous and quantitative neuromuscular monitoring required |
| Patients with cancer | Chemotherapy and radiotherapy can lead to liver and kidney damage, which affects the metabolism and excretion of muscle relaxants. Some cytostatics, such as cyclophosphamide, can inhibit cholinesterase activity, leading to prolonged effects of depolarizing muscle relaxants such as succinylcholine, increasing the risk of prolonged apnoea. Paradoxically, unexpected resistance to rocuronium and atracurium has also been reported in a patient with colorectal cancer due to a paraneoplastic syndrome []77 | Muscle relaxants whose metabolism is independent of hepatic and renal function, such as cisatracurium, which undergoes Hofmann elimination, are recommended.Due to altered pharmacokinetics and pharmacodynamics, individual dose adjustment of muscle relaxants is necessary | Efficacy of neostigmine may be reduced in patients with reduced cholinesterase activity following chemotherapy.Sugammadex is effective in reversing the blockade induced by aminosteroid muscle relaxants such as rocuronium []. Its elimination is predominantly renal, which may be important in patients with impaired renal function following cancer therapy76 | Peripheral nerve stimulation and monitoring of muscle response allows the degree of neuromuscular blockade to be accurately assessed |
| AMG – acceleromyography. | ||||