Infusion of Atracurium in Neonates, Infants and Children

Abstract

The doses of atracurium (by infusion) required to maintain steady-state (90-95%) neuromuscular block were assessed in 75 children aged 9 days to 17 yr during balanced anaesthesia. Following the intubating dose of atracurium 0.4 mg kg-1 and after the recovery of single twitch to 5-10% of control (monitored by evoked EMG of hypothenar muscle), an infusion of atracurium 0.5 mg kg-1 h-1 was started. In 22 of the patients this initial rate resulted in the desired steady state; 32 patients required one, and 21 required two or more adjustments in rate. The mean single twitch value at steady-state was 6.6 +/- 0.3% (SEM), which is equal to 93% neuromuscular block. The infusion requirement to maintain the steady state neuromuscular block in all paediatric patients more than 1 month old was constant (0.53 +/- 0.01 mg kg-1 h-1). The infusion requirement of neonates up to 1 month old was 25% less (0.40 +/- 0.02 mg kg-1 h-1; P = 0.003). A significant correlation (n = 75, r = 0.76, P less than 0.001) was found between the infusion rate (mg m-2 h-1) and the logarithm of the body surface area.

The effects of age, isoflurane and sevoflurane on atracurium in lambs

“…The dose‐response relationship of atracurium is age‐dependent in humans (Brandom et al. 1984, 1985, 1986; Meretoja & Kalli 1986; Kalli & Meretoja 1988), and is similar to that of other neuromuscular blocking agents. The observed differences between neonates, infants and adults are typically attributed to decreasing extracellular fluid volume and, therefore, the drug’s apparent volume of distribution (Brandom et al.…”

Anaesthesia for lambs undergoing spinal surgery: a case series

“…First, responses to injectable drugs were similar to those recorded in adult sheep 419 in this laboratory indicating that some injectable drugs may be safely used in young ruminants-at least those whose clinical activity does not depend on enzymatic elimination. Atracurium undergoes spontaneous molecular degradation in vivo so its duration of action is independent of enzyme function, and has been used in human neonates (Kalli 1988, Meakin 1988. There is no information on the disposition of ketamine in sheep although its duration of action depends on redistribution, and hepatic function in humans, horses, dogs and primates, and on renal excretion in cats and rats (Wright 1982).…”

“…Signs of residual weakness point to 're-curarization' or the re-instatement of neuromuscular block as the cause of death. However, atracurium demonstrates non- Clutton, Murison & Funnell cumulative pharmacokinetic properties in human infants (Kalli 1988) and the presence of facial muscle activity immediately before arrest refutes this possibility (facial muscles are most sensitive to neuromuscular blocking agents). Increased movement in response to edrophonium injection would have confirmed the presence of residual neuromuscular blockade at this time.…”

Suspected toxicity of atracurium in the neonate

“…Atracurium is used in a number of UK neonatal units as medication for intubation (5). Previous groups have suggested that neonates are more sensitive to atracurium than infants and also that a lower body temperature may increase sensitivity (4,6,7).…”