Accelerated reversal of atracurium blockade with divided doses of neostigmine

Edrophonium priming alters the course of neuromuscular recovery from a pipecuronium neuromuscular blockade

This study was designed to investigate the effect of divided administration of edrophonium on the course of neuromuscular recovery from a pipecuronium neuromuscular blockade. During thiopentone-nitrous oxide-halothane anaesthesia 48 patients were given pipecuronium 70 micrograms.kg-1. Patients were randomly assigned to one of four groups (n = 12 in each) to receive either edrophonium 1 mg.kg-1 (Groups I and II) or edrophonium 0.75 mg.kg-1 (Groups III and IV). In Groups I and III (single-dose groups), edrophonium was administered as a single bolus dose. In Groups II and IV (divided-dose groups) edrophonium was administered as an initial dose of 0.25 mg.kg-1 followed three minutes later by either 0.75 or 0.50 mg.kg-1 respectively. Reversal was attempted at 20% spontaneous recovery of twitch height. Administration of edrophonium in divided doses (Groups II and IV) accelerated the reversal of the pipecuronium neuromuscular blockade. At ten minutes post-reversal, train-of-four (TOF) ratio recovery reached 0.75 or more in 12 (100%) and in ten (83%) patients in Groups II and IV respectively. Similarly, times to attain a TOF of 0.75 (SEM) were shorter in the divided-dose groups than in the single-dose groups (P less than 0.05), being 354.5 (38.7) and 398.3 (49.1) sec in Groups II and IV vs 705.4 (66.6) and 651.2 (54.3) sec in Groups I and III respectively. Time was counted from the first administration of edrophonium. It is concluded that administration of edrophonium in divided doses produced a faster reversal of residual pipecuronium-induced neuromuscular blockade than single bolus administration. Also, administration in divided doses reduced the requirements of edrophonium needed for reversal of pipecuronium neuromuscular blockade.

Edrophonium priming for antagonism of atracurium neuromuscular blockade

Edrophonium administered in divided doses has been reported to accelerate antagonism of neuromuscular blockade, i.e., a "priming" effect. Since measured onset times can be affected by the type of stimulation used, this effect was studied using both train-of-four (TOF) and single twitch (ST) stimulation. During thiopentone-nitrous oxide-enflurane anaesthesia 20 adults were given atracurium 0.5 mg.kg-1. Both ulnar nerves were stimulated with TOF every 12 sec until one per cent recovery of first twitch (T1). At this time, ST stimulation was applied to one arm, selected at random. When the mean value of T1 and ST reached ten per cent of control, edrophonium, 1 mg.kg-1, preceded by atropine was given either as a single dose, or in two doses consisting of 0.2 mg.kg-1 followed by 0.8 mg.kg-1 three minutes later. No statistically significant differences were observed between T1 and ST for the next ten minutes, whether edrophonium had been given in single or divided doses. Giving edrophonium in divided doses did not improve recovery significantly, measured with either T1, ST or train-of-four ratio (T4/T1). Five minutes after the first administration of edrophonium, T1 was (mean +/- SEM) 86 +/- 3 and 86 +/- 2 per cent control in the single and divided dose groups respectively. Corresponding values for ST were 89 +/- 1 and 89 +/- 2 per cent (NS), and for TOF, 49 +/- 3 and 57 +/- 3 per cent (NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Train-of-four ratio after antagonism of atracurium with edrophonium: influence of different priming doses of edrophonium

This study was designed to investigate the effect of different priming doses of edrophonium on the relationship between the the recovery of the first twitch of the train-of-four (T1) and train-of-four (TOF) ratio. This relationship was studied after the administration of the full dose of the antagonist in all groups. Edrophonium 1.0 mg.kg-1 was administered either in a single bolus dose (Group I, controls) or in an initial dose of 0.05, 0.1, 0.15 or 0.2 mg.kg-1 followed one minute later by the remainder of the 1.0 mg.kg-1 dose in Groups II to V. Reversal was attempted at the ten per cent spontaneous recovery of twitch height (T1) from atracurium-induced neuromuscular blockade. Of all the groups studied, Group V had a significantly greater recovery in the TOF ratio at any given T1 value. When first twitch tension (T1) had recovered to 100 per cent of the control, it was found for the same tension that the TOF ratio was greater in Group V, being 0.75 compared to 0.63, 0.65, 0.65 and 0.64 in Groups I to IV respectively. The implication is that this differential ability to reverse fade (or prejunctional activity) may be involved in the acceleration of recovery.

"Priming" with neostigmine: failure to accelerate reversal of single twitch and train-of-four responses

Train-of-four stimulation can shorten the apparent onset time of neuromuscular blocking drugs. This study was designed to verify whether the same occurred with neostigmine-assisted recovery, and whether this apparent acceleration could explain the previously reported effectiveness of the priming technique for reversal agents. Fourteen adults received atracurium, 0.5 mg.kg-1, during a thiopentone-nitrous oxide-enflurane anaesthetic. The ulnar nerves of both arms were stimulated with train-of-four stimulation every 12 seconds until 1 per cent recovery of first twitch, at which time stimulation in one arm was switched to single twitch. When mean first twitch height reached 10 per cent of control, neostigmine, 0.04 mg.kg-1, was administered either as a single bolus, or as a "priming" dose of 0.01 mg.kg-1, followed 3 min later by 0.03 mg.kg-1. No statistically significant differences were observed between single twitch in one arm and first twitch height of the train-of-four in the other arm for the next 10 min. With priming, first twitch height was 45 +/- (SEM) 5 per cent at 5 min and 85 +/- 6 per cent at 10 min, compared with 72 +/- 5 per cent (p less than 0.05) and 91 +/- 2 per cent (NS) respectively without priming. Train-of-four ratio was 28 +/- 3 per cent at 5 min and 65 +/- 5 per cent at 10 min with priming, versus 53 +/- 4 per cent (P less than 0.05) and 73 +/- 3 per cent (NS) respectively without priming.(ABSTRACT TRUNCATED AT 250 WORDS)

Priming with anti-cholinesterases--the effect of different priming doses of edrophonium

The effect of different priming doses of edrophonium were studied in 77 patients divided into seven groups (n = 11 in each). Edrophonium 1.0 mg.kg-1 was administered either in a single bolus dose (Group I; controls) or in an initial dose of 0.05, 0.1, 0.15, 0.2, 0.25 or 0.3 mg.kg-1 followed one minute later by the remainder of the 1.0 mg.kg-1 dose in Groups II to VII respectively. Reversal was attempted at ten per cent spontaneous recovery of twitch height (T1) from atracurium-induced neuromuscular blockade. Increasing the size of the priming dose from 0.05 to 0.2 mg.kg-1 resulted in a stepwise increase (p less than 0.05) in recovery of T1 and train-of-four (TOF) ratio. Higher priming doses (0.25 and 0.3 mg.kg-1) were not associated with further improvement in T1 and TOF recovery. Reversal time, that is the time taken from the first injection of edrophonium until the TOF ratio value had reached 0.75 was significantly faster (p less than 0.01) following priming with edrophonium 0.2 mg.kg-1 (Group V) when compared to Groups I, II, III, IV and VI. Reversal times were also significantly faster in Groups IV and VI when compared to the control group. It is concluded that 0.2 mg.kg-1 appears to be the optimal priming dose for administration of edrophonium in divided doses.

Priming with anti-cholinesterases--the effect of different combinations of anti-cholinesterases and different priming intervals

This study was designed to investigate the effect of different combinations of neostigmine and edrophonium when administered in divided doses and the effect of different intervals (priming intervals) between the doses. Seventy-two patients divided into 12 groups (n = 6 in each) were included in the study. An initial dose of neostigmine 0.012 mg.kg-1 or edrophonium 0.2 mg.kg-1 was administered, followed at different priming intervals (1, 2 or 3 min) by either edrophonium 0.8 mg.kg-1 or neostigmine 0.048 mg.kg-1 for antagonism of atracurium-induced neuromuscular blockade. Reversal was attempted at 10 per cent spontaneous recovery of twitch height. Adequate reversal of neuromuscular block (train-of-four ratio of 0.75) was achieved in all patients. Significant (p less than 0.05) acceleration of the recovery index (time taken for the twitch height to recover from 25 to 75 per cent of control) and reversal time (time taken from the end of injection of the priming dose until TOF ratio value had reached 0.75) was obtained in groups which received edrophonium-edrophonium combination. Recovery indices and reversal times were found to be significantly shorter (p less than 0.05) with a 1 min priming interval. In two additional groups of patients premedicated and anaesthetized as the others equipotent mixtures of the antagonists were administered as a single bolus dose. Reversal times were significantly longer (p less than 0.05) when compared to those given the same amounts of the combination but in divided doses with a 1 min priming interval.(ABSTRACT TRUNCATED AT 250 WORDS)