Mohamed Abdulatif

Caudal Neostigmine, Bupivacaine, and Their Combination for Postoperative Pain Management After Hypospadias Surgery in Children

In a randomized, double-blinded study, we examined the analgesic efficacy of caudal neostigmine, bupivacaine, or a mixture of both drugs in 60 children. After the induction of general anesthesia, children were allocated randomly into three groups (n = 20) to receive a caudal injection of either 0.25% bupivacaine 1 mL/kg, with or without neostigmine 2 &mgr;g/kg, or neostigmine 2 &mgr;g/kg in normal saline 1 mL/kg. Intraoperatively, children receiving caudal bupivacaine or a bupivacaine/neostigmine mixture maintained hemodynamic stability, required less inhaled anesthetics, and had a shorter recovery time compared with the caudal neostigmine alone. Postoperatively, the caudal bupivacaine/neostigmine mixture resulted in superior analgesia compared with the other two groups. Recovery to first rescue analgesic times were (mean ± sd) 22.8 ± 2.9 h, 8.1 ± 5.9 h, and 5.2 ± 2.1 h in the bupivacaine/neostigmine, bupivacaine, and neostigmine groups, respectively (P < 0.001). In addition, the bupivacaine and neostigmine groups received more doses of paracetamol than the bupivacaine/neostigmine group to maintain adequate analgesia in the first 24 postoperative h. Postoperative vomiting occurred in 25%, 10%, and 30% in the caudal bupivacaine/neostigmine, bupivacaine, and neostigmine groups, respectively (P < 0.01). We conclude that caudal neostigmine 2 &mgr;g/kg provides postoperative analgesia comparable to caudal bupivacaine in children undergoing hypospadias repair surgery.

Rapid tracheal intubation with atracurium - a comparison of priming intervals

Abstractdetermine the optimal interval between the administration of the priming dose and the intubating dose, atracurium was given to 44 patients either in a single dose of 0.5 mg.kg-1 or in an initial dose of0.06mg.kg-1 followed two, three or five minutes later with 0.44 mg.kg-1.When atracurium was given as a single bolus of 0.5 mg. kg-1 the time to 100 per cent twitch suppression (onset time) was90.9 ± 36 (mean ± SD) seconds. When the priming interval was two minutes, the onset time of the intubating dose was 76.6 ± 42.2 seconds (p = NS). But when the priming interval was three or five minutes, the onset timeswere42.2 ± 16.5(p<0.01)and52.6 ± 28.8(p < 0.05) seconds respectively.Waiting for five minutes after the administration of the priming dose did not improve the intubating conditions. It is concluded that three minutes appears to be the optimal time interval for the administration of atracurium in divided doses. When a priming dose of atracurium is given three minutes before the intubating dose, it can provide an alternative to succinylcholine for rapid endotracheal intubation.RésuméAfin de déterminer l’ interval optimal entre I’administration de la dose d’amorce et de la dose d’intubation, de I’atracurium a été administré è 44 patients soit en une dose unique de 0.5 mg.kg-1, ou en une dose initiale de 0.06mg.kg-1 suivi de deux, trois, ou cinq minutes plus tard de 0.44 mg.kg-1.Quand I’atracurium a été donné comme dose unique de 0.5 mg.kg-1 le temps d’abolition à 100 pour cent de la réponse au twitch (temps d’installation) était de 90.0 ± 36 (moyenne ± SD) secondes. Lorsque I’intervalle d’amorce etait de deux minutes, le temps d’installation de la dose d’intubation était de 76.6±42.2 secondes (p = NS). Et lorsque I’intervalle d’amorce était de trois ou cinq minutes, les intervalles d’installation étaient de 42.2 ± 16.5 (p<0.01) et 52.6±28.8 (p<0.05) secondes respectivement.Une attente supérieure à cinq minutes après I’administration de la dose d’amorce n’a pas amélioré d’avantage les conditions d’intubation.Il est conclu que trois minutes apparaissent comme étant I’intervalle de temps optimal pour Vadministration de iatracurium à dose divisée. Quand une dose d’amorce d’atracurium est donnée trois minutes avant la dose d’intubation elle peut fournir une alternative à la succinyl-choline pour une intubation endotrachéal rapide.

Priming with atracurium: improving intubating conditions with additional doses of thiopental.

The effects of different intubating doses of atracurium on the time of onset, and the effect of an additional dose of thiopental on intubating conditions, were studied in 72 patients divided into six groups (n = 12 in each). Stratified sampling was used to obtain an even sex distribution. Groups I, III, and V (controls) received atracurium as a single bolus dose of 0.4, 0.5 or 0.6 mg/kg respectively. Groups 11, IV, and VI received an initial (priming) dose of 0.05 mg/kg followed 3 min later by 0.35, 0.45, or 0.55 mg/kg respectively. The time of onset, that is the time from the intubating dose to complete suppression of the train-of-four (TOF) response, was significantly accelerated after administration of atracurium in divided doses. Increasing the intubating dose of atracurium after an initial 0.05 mg/kg from 0.35 to 0.55 mg/kg did not result in further significant acceleration of the onset time, but resulted in prolongation of the duration of neuromuscular blockade. When divided doses of atracurium were given, administration of 2 mg/kg thiopental (in addition to the 5 mg/kg used for induction) before the injection of the intubating dose resulted in improvement of intubating conditions as reflected by statistically significant changes in intubating scores. This result was probably due to the increase by thiopental in the depth of anesthesia. Therefore, when thiopental is given as supplement, the priming technique can be made to provide better conditions for tracheal intubation in less than 90 sec.

Dose-response Relationships for Edrophonium and Neostigmine Antagonism of Rocuronium Bromide (org 9426)-induced Neuromuscular Blockade

BackgroundRocuronium bromide (ORG 9426) Is a new nondepolarizing muscle relaxant with a rapid onset but an intermediate duration of action. The dose-response relationships for neostigmine and edrophonium were studied during antagonism of neuromuscular block induced by rocuronium bromide. MethodsSixty-four ASA physical status 1 or 2 adults were given 0.6 mg/kg rocuronium bromide during thiopental-fentanyl-nitrous oxide-isoilurane anesthesia. Train-of-four (TOF) stimulation was applied to the ulnar nerve every 10 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height reached 10% of its initial control value, edrophonium (0.1, 0.2, 0.4, or 1 mg/kg) or neostigmine (0.005, 0.01, 0.02, or 0.05 mg/kg) was administered by random allocation. Neuromuscular function in another eight subjects was allowed to recover spontaneously. Assisted recovery was defined as actual recovery minus mean spontaneous recovery in patients who were not given antagonists. ResultsThe dose-response curves for neostigmine- and edrophonium-assisted antagonism of rocuronium bromide neuromuscular blockade for the single twitch and TOF ratio were not parallel. The doses of neostigmine required to achieve 50% and 80% recovery (ED50 and ED80, respectively) of the first twitch after 10 min were 0.017 (0.001) and 0.033 (0.001) mg/kg (mean (standard error of estimate for the mean)), respectively. Corresponding ED50 and ED80 values for edrophonium were 0.161 (0.001) and 0.690 (0.001) mg/kg, respectively. These values corresponded to neostigmine:edrophonium potency ratios of 9.5 (0.56) and 21 (0.67) for first twitch ED50 and ED80 height, respectively. The calculated doses producing ED50 of the TOF ratio at 10 min were 0.017 (0.001) and 0.469 (0.001) mg/kg for neostigmine and edrophonium, respectively. These values corresponded to a potency ratio of 27.5 (1.66). ConclusionsUnder the conditions described in this study, if reversal was attempted at 10% first twitch recovery, edrophonium was less capable than neostigmine of reversing fade (potency ratio of 19.2 and 27.5 at 5 and 10 min, respectively) than first twitch (potency ratio of 6.7 and 9.5 at 5 and 10 min, respectively) during antagonism of rocuronium bromide-induced blockade. Edrophonium was found to be less effective than neostigmine at reversing rocuronium bromide-induced TOF fade.

Priming with anticholinesterases — the effect of different combinations of anticholinesterases 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 < 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 < 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 < 0.05) when compared to those given the same amounts of the combination but in divided doses with a 1 min priming interval.It is concluded that the administration of edrophonium in divided doses (0.2 mg-kg-1 followed one minute later by 0.8 mg-kg-1) is the best combination of those studied for the antagonism of profound (90 per cent depression of TJ) neuromuscular blockade induced by atracurium. With this technique of administration, a TOF ratio of 0.75 can be obtained in about 4 min.RésuméLa présente étude a été conçue afin ďinvestiguer les effets de différentes combinaisons de néostigmine et ďédrophonium lorsqu’administrés en doses fractionnées ainsi que ľeffet des différents intervals (interval ďamorce) entre les doses. Soixante-douze patients divisés en 12 groupes (n = 6 pour chaque groupe) ont été inclus dans ľétude. Une dose initiale de néostigmine 0.012 mg-kg-1 ou ďédrophonium 0.2 mg-kg-1 a été administrée suivie, à des intervals ďamorce différents (1,2 ou 3 minutes), par soit ľédrophonium 0.8 mg-kg-1 ou la néostigmine 0.048 mg-kg-1 afin ďantagoniser le blocage neuromusculaire induit par ľatracurium. La décurarisation a été tentée après une récupération spontanée de dix pour cent de la hauteur du twitch. Un antagonisme adéquat du bloc neuromusculaire (rapport de ľondée-de-quatre (TOF) de 0.75) a été obtenu chez tous les patients. Une accélération significative (p < 0.05) de ľindice de recouvrement (temps pris pour que la hauteur du twitch retourne de 25 à 75 pour cent du contrôle) et le temps ďantagonisme (temps pris à partir de la fin de ľinjection de la dose ďamorce jusqu’à ľobtention ďun rapport TOF de 0.75) ont été obtenus dans les groupes avant reçu la combinaison ďédrophoniumédrophonium. Les indices de récupération et les temps ďantagonisme ont été trouvés significativement plus courts (p < 0.05) après une minute ďinverval ďamorce.Dans deux groupes additionnels de patients prémédiqués et anesthésiés comme les autres, des mélanges équipotents ďantagonistes ont été administrés en une dose unique. Les temps ďantagonisme ont été trouvés significativement plus longs (p < 0.05) en comparaison à ceux qui ont reçu la même quantité de mélanges en doses fractionnées avec un interval ďamorce de une minute.Il est conclut que I’administration ďédrophonium à doses fractionnées (0.2 mg-kg-1 suivi une minute plus tard par 0.8 mg-kg-1) est la meilleure combinaison pour le groupe étudié afin ďantagoniser un bloc neuromusculaire profond (une dépression de 90 pour cent de 77) induit par ľatracurium. Avec cette technique ďadministration un rapport TOF de 0.75 peut être obtenu dans approximativement quatre minutes.

Accelerated reversal of atracurium blockade with divided doses of neostigmine

The hypothesis that administration of neostigmine in divided doses might accelerate the antagonism of neuromuscular blockade was investigated. Neostigmine 0.05 mg.kg-1 was administered either in a single bolus dose (Group I, n = 16) or in an initial dose of 0.01 mg-kg-1 followed three minutes later by 0.04 mg-kg-1 (Group II, n = 16) for antagonism of atracurium-induced blockade. Reversal was attempted at 10 per cent spontaneous recovery of twitch height. The mean time (±SD)from the first injection of the drug until the train-of-four (TOFj ratio value had reached 0.75 was significantly shorter in Group II (p < 0.05) than in Group I (391.8 ± 83.3 and 468.6 ± 150.3 seconds respectively). The rate of TOF ratio recovery was 2.5 times faster after neostigmine administration in divided doses.It is concluded that administration of neostigmine in divided doses, as described in this study, produced a significantly faster reversal of residual atracurium-induced neuromuscular blockade as compared to a single bolus administration.RésuméL’hypothèse que l’administration de neostigmine à doses divisées peut accélérer l’antagonisme du block neuromusculaire était investiguée. La néostigmine 0.05 mgkg-1 était administrée soit en bolus unique (Group I, n = 16) ou en une dose initiale de 0.01 mg.kg-1 suivi trois minutes plus tard de 0.04 mg.kg-1 (Group 11, n = 16) pour l’antagonisme d’un block induit par l’atracurium. Le renversement du block était tenté lorsqu’on a observé le recouvrement spontané de dix pour cent dans la hauteur de twitch. Le temps moyen ( ± SD) à partir de la première injection du médicament jusqu’à l’obtention d’une ondée de quatre (TOF) de 75 pour cent était significativement plus cour dans le groupe II (p < 0.05) que dans le Groupe I (391.8 ± 83.3 et 468.6 ± 150.3 secondes respectivement). Le taux de recouvrement de l’ondée de quatre (TOF) était 2.5 fois plus rapide après l’administration de neostigmine à dose divisée.On conclue que l’administration de néostigmine à doses divisées, telle que décrites dans cette étude, produit un antagonisme significativement plus rapide du block neuromusculaire induit par l’atracurium comparativement à l’administration de la néostigmine en un bolus unique.

Priming with anticholinesterases — 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 (TI) 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 < 0.05) in recovery of TI and train-of-four (TOF) ratio. Higher priming doses (0.25 and 0.3 mg-kg-1) were not associated with further improvement in TI 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 < 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.RésuméĽeffet de différentes doses ďamorce ďédrophonium a été étudié chez 77 patients divisés en sept groupes (n = 11). Ľédrophonium 1.0 mg-kg-1 a été administré soit en une dose unique (Groupe I, contrôle) ou en une dose initiale de 0.05, 0.1, 0.15, 0.2, 0.25 ou 0.3 mg-kg-1 suivi une minute plus tard par le restant de la dose de 1.0 mg-kg-1 pour les Groupes II à VII. Ľantagonisme a été tenté après une récupération spontanée à dix pour cent de la hauteur de twitch (TI) après un bloc neuromusculaire induit par ľatracurium. Ľaugmentation de la dose ďamorce de 0.05 à 0.2 mg-kg-1 a produit une augmentation de plus en plus accrue (p < 0.05) dans la récupération de TI et du rapport de ľondée-de-quatre (TOF). La plus grande dose ďamorce (0.25 et 0.3 mg-kg-1) n’était pas associée avec de plus grandes améliorations dans la récupération de TI et TOF. Le temps ďantagonisme, qui représente le temps du début de la première injection ďédrophonium jusqu’à ľobtention ďun rapport de TOF de 0.75 était significativement plus rapide (p < 0.01) après la dose ďamorce ďédrophonium de 0.2 mg-kg-1 Groupe V) en comparaison Groupe I, II, III, IV et VI. Les temps ďantagonisation étaient aussi significativement plus rapides dans les groupes IV et VI comparativement groupe contrôle. On conclut que la dose de 0.1 mg-kg-1 apparaît optimale comme dose ďamorce pour ľadministration de ľédrophonium en doses fractionnées.

Dose-Response Relationships for Edrophonium and Neostigmine Antagonism of Pipecuronium-Induced Neuromuscular Block

We have studied the dose‐response relationships for neostigmine and edrophonium during antagonism of neuromuscular block induced by pipecuronium bromide. Fifty‐six ASA physical status I or II adults were given pipecuronium 70 pg/kg during fentanyl‐thiopental‐nitrous oxide‐halothane anesthesia. Train‐of‐four (TOF) stimulation was applied to the ulnar nerve every 10 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height reached 20% of its initial control value, edrophonium (0.125, 0.25,0.75, or 1 mg/kg) or neostigmine (0.015,0.03,0.045, or 0.06 mg/ kg) was administered by random allocation. Neuromuscular function in another seven subjects was allowed to recover spontaneously. This study demonstrated that the dose‐response curves for these two drugs for reversal of first twitch and TOF ratio were not parallel. The doses of neostigmine required to achieve 50% (ED50) and 80% (ED80,) recovery of the first twitch after 10 min were 8.5 (7.3‐9.7) and 17.4 (16,2‐18.7) pg/kg [mean (95% confidence intervals)], respectively. Corresponding ED50 and ED[80], values for edrophonium were 84.1 (72.9‐96.9) and 233 (215,7‐253.3) ug/kg, respectively. These values corresponded to neostigmineiedrophonium potency ratios of 9.89 (7.4‐12.3) and 13.4 (11.8‐14.9) for first twitch ED[50], and ED[80], height, respectively. The calculated doses producing 50% (ED[50],) recovery of the TOF ratio at 10 min were 18.8 (17.5‐20.2) and 271.3 (246,5‐298.6) pg/kg for neostigmine and edrophonium, respectively. These values corresponded to a potency ratio of 14.4 (12,8‐15,9). We conclude that both edrophonium and neostigmine were able to reverse a pipecuronium neuromuscular block although their dose‐response curves were not parallel.

The pattern of train-of-four fade after atracurium: influence of different priming doses

This study was designed to investigate the effect of three different priming doses of atracurium—0.06, 0.07, and 0.08 mg/kg—followed 3 min later by the remainder of a 0.5 mg/kg dose on the relationship between the depression in the first twitch of the train-of-four (T1) and train-of-four (TOF) fade. This relationship was studied after the administration of the full dose of the relaxant in all groups. Of all the priming doses, 0.08 mg/kg atracurium, when followed 3 min later by 0.42 mg/kg atracurium, had a significantly greater fade in the TOF ratio at any given T1 value. This may indicate significant prejunctional activity. Acceleration of the onset of neuromuscular blockade was, however, evident in all groups that received atracurium in divided doses. The implication is, therefore, that prejunctional activity may not contribute significantly to the acceleration of onset of neuromuscular blockade after administration of atracurium in divided doses, as described in this study.

Multiple electrocardiographic anomalies during anaesthesia in an athlete

A 22-year-old athlete was scheduled for a minor surgical procedure under general anaesthesia. During anaesthesia, his electrocardiogram demonstrated multiple episodes of dysrhythmias including complete bundle branch block, atrioventricular (AV) block, isorhythmic atrioventricular dissociation with junctional rhythm. Administration of atropine 1.0 mg IV terminated the last episode of dysrhythmias. Postoperatively, a resting 12-lead electrocardiogram showed first degree AV block, ST-segment elevation and prominent U waves. A 24 hour Holter recording demonstrated first degree atrioventricular block, episodes of marked sinus arrhythmias and one episode of sinus tachycardia at a rate of 152 beats ·min-1. Treadmill stress testing revealed peak achieved heart rate of 200 beats·min-1 without ischaemia. These findings collectively indicated athletic heart syndrome. Implications of athletic heart syndrome for the anaesthetist are reviewed and discussed.RésuméUn athlète de 22 ans était cédulé pour une procédure chirurgicale mineure sous anesthésie générale. Lors de ľanesthésie, ľélectrocardiogramme a démontré de multiples épisodes ďarythmie incluant un bloc de branche complet, un bloc AV, une dissociation atrioventricular isorythmique avec un rythme jonctionnel. Ľadministration Ľatropine 1.0 mg IV mit fin à la dernière épisode de dysrythmie. En période postopératoire, un électrocardiogramme à 12 dérivations a démontré un bloc AV du premier degré, une élévation du segment ST ainsi qu’une onde U proéminente. Un Holter de 24 heures a démontré un bloc AV du premier degré, des épisodes marqués ďarythmie sinusale et un épisode de tachycardie sinusale avec une fréquence de 152 battements/minute. Un électro ďeffort n’a pas démontré ďischémie avec une fréquence maximale de 200 battements/minute. Ces trouvailles nous indiquent collectivement la présence ďun syndrome du cœur athlétique. Les implications de ce syndrome du cœur athlétique pour ľanesthésie sont revues et discutées.