Neuromuscular blockade in the elderly patient

Abstract

Neuromuscular blockade is a desirable or even essential component of general anesthesia for major surgical operations. As the population continues to age, and more operations are conducted in the elderly, due consideration must be given to neuromuscular blockade in these patients to avoid possible complications. This review considers the pharmacokinetics and pharmacodynamics of neuromuscular blockade that may be altered in the elderly. Compartment distribution, metabolism, and excretion of drugs may vary due to age-related changes in physiology, altering the duration of action with a need for reduced dosage (eg, aminosteroids). Other drugs (atracurium, cisatracurium) have more reliable duration of action and should perhaps be considered for use in the elderly. The range of interpatient variability that neuromuscular blocking drugs may exhibit is then considered and drugs with a narrower range, such as cisatracurium, may produce more predictable, and inherently safer, outcomes. Ultimately, appropriate neuromuscular monitoring should be used to guide the administration of muscle relaxants so that the risk of residual neuromuscular blockade postoperatively can be minimized. The reliability of various monitoring is considered. This paper concludes with a review of the various reversal agents, namely, anticholinesterase drugs and sugammadex, and the alterations in dosing of these that should be considered for the elderly patient.

Profile of sugammadex for reversal of neuromuscular blockade in the elderly: current perspectives

“…Aging is also associated with decreased muscle blood flow and vascular conductance in the elderly. 12 , 31 Vascular function changes with aging include impaired endothelial function (eg, impaired formation and activation of nitric oxide) and altered reactivity of vascular smooth muscle to sympathetic activity. Age-related structural and functional alterations in the vascular system may explain age-associated reductions in muscle blood flow.…”

“…Advancing age is associated with increased sensitivity to the central nervous system effects of benzodiazepines; propofol, which requires a 40%–50% lower dose in patients aged >65 years; inhalational anesthetic agents; opioids, especially remifentanil; and local anesthetics. 17 , 32 In the field of NM pharmacology, possible changes in receptor biological features (eg, ligand affinity and kinetics), perhaps occurring simultaneously with altered blood flow to muscles, 12 , 17 has been suggested to occur in elderly patients. 33 , 34 These changes involve slower release of NMBAs from receptors, delayed recovery of receptors, and possibly altered receptor expression at the NM junction.…”

“…As a result, lipophilic drugs will have a higher volume of distribution in the elderly, which may lead to more extensive redistribution and a longer elimination half-life of lipophilic drugs. 9 , 12 …”

“…Plasma albumin concentration tends to decrease with age, and structural protein changes occur with age that lead to decreased efficiency of albumin binding, to as little as 20% by the age of 70 years. 9 , 12 …”

“…Therefore, NMB in the elderly should be routinely monitored and completely reversed before awakening patients at the end of anesthesia. 9 – 12 Differences between young and elderly patients with respect to antagonism of NMB by acetylcholinesterase inhibitors have been reported. Young et al noted prolonged duration of action of neostigmine in aged patients (32±10 vs 11±2 minutes, P <0.05), 13 confirming previous data (42±10 vs 13±14 minutes in older vs younger patients, P <0.01).…”