Biomedical subjects

M Abdulatif

Publications and source records attributed to M Abdulatif.

At least 19 recordsLinked to original sources

PubMed2001

Edrophonium antagonism of cisatracurium-induced neuromuscular block: dose requirements in children and adults.

This randomized, controlled study compared edrophonium dose requirements to antagonize cisatracurium-induced neuromuscular block in children and adults. Sixty children, aged two to 10 years, and 60 adults aged 20 to 60 years, all subjects ASA physical status 1 or 2, having propofol, fentanyl and isoflurane-N2O anaesthesia, were studied. Cisatracurium 0.1 mg x kg(-1) was given for muscle relaxation. Neuromuscular block was monitored with accelerometry. Edrophonium 0.1, 0.2, 0.4 or 1 mg x kg(-1) or no anticholinesterase (controls) was given by random allocation to antagonize 90% neuromuscular block in each of the study groups (n=12). Atropine 5 to 10 microg x kg(-1) was given according to edrophonium dose. Onset time of cisatracurium-induced block in children was mean (SD) 2.4 (0.8) versus 4.1 (2.3) minutes in adults, P<0.01. The times to 10% spontaneous recovery of the first twitch (T1) were respectively, 28.4 (5.2) and 41.8 (6.1) minutes in children and adults, P<0.01. Spontaneous and antagonist assisted neuromuscular recovery was more rapid in children. Adequate neuromuscular recovery (train of four (TOF) ratio 80%) was achieved in children at 3 and 10 minutes after edrophonium 1.0 mg kg(-1) and 0.4 mg x kg(-1), respectively. A TOF ratio of 80% was not achieved, within 10 minutes, with any of the four dose levels of edrophonium in adults. The dose of edrophonium to achieve a TOF ratio of 80% (ED(TOF-80)) after 5 and 10 minutes in children were, respectively, mean (SD) 0.85 (0.38) and 0.38 (0.19) mg x kg(-1). The equivalent ED(TOF-80) in adults was outside the edrophonium dose range studied.

Adult↗

PubMed1997

Blood flow and mivacurium-induced neuromuscular block at the orbicularis oculi and adductor pollicis muscles.

We have studied the pattern of blood flow and pharmacodynamic profile of mivacurium-induced block at the adductor pollicis and orbicularis oculi muscles. We studied 30 adult patients anaesthetized with fentanyl, thiopentone, nitrous oxide-isoflurane, and mivacurium 0.2 mg kg-1. Neuromuscular transmission was monitored with accelerometry (TOF Guard, Biometer, Denmark). Blood flow was measured at the two muscles with the use of a laser Doppler flowmeter (Laserflo BPM2, Vasamedics, USA). All patients developed 100% neuromuscular block at the adductor pollicis muscle. Mean maximum neuromuscular block at the orbicularis oculi was 96.4 (SD 3.5)% (ns). Onset time, time required for 25% and 75% recovery of the first twitch in the train-of-four (T1), and a train-of-four ratio (T4/T1) of 90% at the orbicularis oculi were respectively, mean 130.4 (SD 28.5) s, 9.1 (3.2) min, 16.2 (3.9) min and 20.2 (4.3) min and were significantly shorter than the corresponding values at the adductor pollicis: 202.7 (37.2) s, 12.9 (3.9) min, 21.1 (5.1) min and 30.8 (7.4) min. For a given T1, there was significantly less train-of-four fade (T4/T1) at the orbicularis oculi than at the adductor pollicis muscle during recovery. Blood flow was comparable at the two muscles before induction of anaesthesia. Thiopentone significantly increased thenar muscle blood flow from 2.9 (1.5) to 12.3 (6.8) ml 100 g-1 min-1, with a further increase to 22.7 (8.0) ml 100 g-1 min-1 after isoflurane (P < 0.001). Blood flow at the orbicularis oculi was not altered by thiopentone or isoflurane and was consistently lower than that at the adductor pollicis muscle. We conclude that the different pharmacodynamic profiles of mivacurium-induced block at the orbicularis oculi and adductor pollicis muscles were not related primarily to a difference in blood flows.

Adult↗

PubMed1996

Rocuronium priming of atracurium-induced neuromuscular blockade: the use of short priming intervals.

STUDY OBJECTIVE: To evaluate the effects of priming doses of rocuronium on the duration of priming interval and on the outcome of priming sequence using rocuronium-atracurium combination. DESIGN: Three phase, randomized, controlled study. SETTING: Inpatient anesthesia in a university hospital. PATIENTS: 144 ASA physical status I and II patients, 19 to 57 years of age, weighing 50 to 90 kg, and undergoing low-risk elective surgery. INTERVENTIONS: Phase I, two equal groups (n = 12) of adult patients anesthetized with propofol, fentanyl, and nitrous oxide (N2O), received a priming dose of rocuronium 0.1 mg/kg or vecuronium 0.015 mg/kg. Phase II included six equal groups (n = 12): Groups 1, 2, and 3 received a priming dose of rocuronium 0.1 mg/kg and atracurium 0.42 mg/kg for intubation. The priming intervals were, respectively, 1, 1.5, or 2 minutes in Groups 1, 2, and 3. Groups 4, 5, and 6 received, respectively, a bolus dose of rocuronium 0.6 mg/kg, atracurium 0.5 mg/kg, or succinylcholine 1 mg/kg. Intubation was performed at maximum block. Phase III included four equal groups (n = 12). A priming dose of rocuronium 0.1 mg/kg (Group 1) or a placebo (Groups 2, 3, and 4) was given to awake patients. Anesthesia was induced during the one-minute priming interval. Intubating doses of atracurium 0.42 mg/kg, rocuronium 0.6 mg/kg, atracurium 0.5 mg/kg, or succinylcholine 1 mg/kg were given to Groups 1, 2, 3, and 4, respectively. Intubation was attempted 1 minute after intubating doses were administered. MEASUREMENTS AND MAIN RESULTS: Adductor pollicis response to train-of-four stimulation was recorded mechanically in Phases I and II only. The priming interval after rocuronium 0.1 mg/kg was in the range of 1 to 2 minutes. Priming doses of rocuronium resulted in significant acceleration in the onset time of intubating doses of atracurium, irrespective of the duration of the priming interval. The onset times [mean (SD)] following rocuronium-atracurium sequence in Groups 1, 2, and 3 were, respectively, 67 (17), 73 (14), and 66 (18) seconds and were comparable with the onset of bolus doses of rocuronium and succinylcholine. In Phase II, good to excellent intubating conditions were obtained in 41% to 58% of patients included in Groups 1 through 5. Excellent to good intubating conditions were obtained in all patients (100%) who received succinylcholine. In Phase III, good to excellent intubating conditions were obtained in 91% of patients who received recuronium-atracurium sequence. Symptoms of muscle weakness were not reported. CONCLUSIONS: Priming doses of recuroniums 0.1 mg/kg reduce the priming interval to 1 minute, allow early induction of anesthesia, eliminate patient discomfort, and accelerate the onset time of altracurium with intubating conditions comparable with succinylcholine and rocuronium.

Adult↗

PubMed1996

Edrophonium antagonism of intense mivacurium-induced neuromuscular block in children.

We have studied the time course of recovery after administration of edrophonium during intense mivacurium block in children aged 2-10 yr, using thumb acceleration in response to train-of-four (TOF) stimulation. Forty-three children receiving alfentanil, propofol, nitrous oxide, isoflurane anaesthesia and mivacurium 0.2 mg kg-1 were allocated randomly to one of three groups. Patients in group 1 (n = 15) received edrophonium 1 mg kg-1, 2 min after maximum block (intense block group). At the time of administration of edrophonium in this group, there was no response to TOF stimulation (100% block) and the post-tetanic count was 10.7 (range 0-20). Patients in group 2 received the same dose of edrophonium after 10% recovery of the first twitch (T1) in the TOF (conventional reversal). Patients in group 3 (n = 13) recovered spontaneously. All patients developed complete suppression of twitch height in response to the bolus dose of mivacurium. All recovery times were measured from the point of maximum block after mivacurium. Mean time for 25% recovery of T1 (clinical duration) was 3.8 (SD 1.1) min in the intense block group. This was significantly shorter than the conventional reversal (8.3 (2.4) min) and spontaneous recovery (9.2 (3.5) min) groups (P < 0.001). The times for 75% and 90% recovery of T1 were shorter in the intense block group (9.4 (2.8), 12.3 (4.2) min) compared with the conventional (13.1 (3.8), 17.3 (4.8) min) and spontaneous recovery (14.9 (4.5), 17.9 (5.2) min) groups (P < 0.01). Total recovery time required for 70% recovery of the TOF ratio (T4/T1) was 8.8 (2.4) min in the intense block group. This was significantly shorter than the conventional reversal (11.9 (3.2) min) (P < 0.05) and spontaneous recovery (17.1 (4.0) min) groups (P < 0.001). Conventional reversal was associated with a shorter total recovery time compared with spontaneous recovery (P < 0.01). The recovery index (time interval between T1 25% and 75%) was comparable in groups 1-3 (5.5 (2.0), 4.8 (2.1) and 5.7 (1.4) min respectively). Ten minutes after development of maximum block, the numbers of patients who recovered adequately (TOF ratio 70% or more) were, respectively, 12 (80%), 8 (53%) and 1 (8%) in groups 1-3. We conclude that edrophonium antagonized intense (no response to TOF stimulation) mivacurium-induced block in children, with significant reduction in the recovery times of T1 and TOF ratio compared with conventional reversal and spontaneous recovery.

Anesthesia, General↗

PubMed1996

Dose-response relationships for neostigmine antagonism of rocuronium-induced neuromuscular block in children and adults.

Dose-response relationships for the antagonism of intermediate-acting neuromuscular blocking agents have not been evaluated previously in children. We have examined the dose-response relationships for neostigmine antagonism of 90% rocuronium-induced neuromuscular block in children and adults, during nitrous oxide-1 MAC of isoflurane anaesthesia. We studied 40 children, aged 2-10 yr, and 50 adults, aged 18-60 yr; all received a single bolus dose of rocuronium 0.6 mg kg-1 and accelerometry was used to monitor neuromuscular transmission. When the first twitch of the train-of-four (TOF) response (T1) recovered to 10% of its control (T0), one of five doses of neostigmine 0, 5, 10, 20 or 50 micrograms kg-1 was given by random allocation to each of the study groups (n = 8 children and n = 10 adults). Recovery of T1 and TOF ratio (T4/T1%) was recorded for 10 min after initial administration of neostigmine. Onset time of rocuronium-induced block was faster in children than in adults (mean 64.6 (95% confidence intervals 57.7-71.5) s vs 83.7 (70.7-96.6) s; P < 0.05). The time to 10% recovery of T1/T0 was shorter in children than in adults (25.4 (22.9-27.9) min vs 38.8 (36.1-41.4) min; P < 0.001). Spontaneous and antagonist-assisted recovery were more rapid in children than in adults. Adequate recovery (T4/T1 of 80%) occurred in children at 4, 5 and 8 min after neostigmine 50, 20 and 10 micrograms kg-1, respectively. Adequate recovery was not produced in adults by any dose of neostigmine within 10 min. The effective doses of neostigmine required to achieve a TOF ratio of 80% (ED80) after 10 min in children and adults were, respectively, 7.10 (5.2-9.8) micrograms kg-1 and 56.56 (45.5-71.9) micrograms kg-1 (P < 0.001). There was no advantage in administering doses of neostigmine greater than 20 micrograms kg-1 to antagonize 90% rocuronium-induced neuromuscular block in children. In contrast, it appeared prudent to use neostigmine 50 micrograms kg-1 or more for adequate antagonism of a similar degree of block in adults.

Adolescent↗

PubMed1995

Surgeon-controlled mivacurium administration during elective caesarean section.

We have compared the dose requirements and recovery characteristics of a continuous mivacurium infusion given by the anaesthetist to maintain 95-100% block at the hand muscles with that of a surgeon-controlled, on-demand dosing technique based on the direct assessment of abdominal muscle tone during elective Caesarean section. Twenty-four full term pregnant patients were included. A rapid-sequence induction using thiopentone 3-5 mg.kg-1 and succinylcholine 1 mg.kg-1 was used. Anaesthesia was maintained with fentanyl, N2O and isoflurane 0.5%. The mechanomyographic response of the adductor pollicis muscle to supramaximal train-of-four (TOF) ulnar nerve stimulation was recorded. Muscle relaxation was achieved initially with mivacurium 0.1 mg.kg-1 followed either by a continuous infusion of mivacurium to maintain 95-100% block at the adductor pollicis muscle (n = 12) or by surgeon-controlled relaxation (SCR) technique using a syringe pump for patient-controlled analgesia to administer on-demand doses of mivacurium 0.05 mg.kg-1 (n = 12). The lockout interval was three minutes and the maximum hourly dose of mivacurium allowed was 0.6 mg.kg-1. The total doses of mivacurium (mean +/- SD) were 23.2 +/- 10.4 and 12.4 +/- 3.5 mg in the infusion and SCR groups, P < 0.01. On-demand, surgeon-controlled doses of mivacurium were injected at a mean of T1 42.3 +/- 36%. At the end of surgery, T1 and TOF ratio were respectively 16.7 +/- 13%, 5 +/- 10% and 48 +/- 37%, 30 +/- 24% in the infusion and SCR groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗

PubMed1995

Recovery characteristics after early administration of anticholinesterases during intense mivacurium-induced neuromuscular block.

The time course of recovery after early administration of anticholinesterases during intense mivacurium-induced block was evaluated by recording the mechanomyographic response of the adductor pollicis to post-tetanic count (PTC) and train-of-four (TOF) ulnar nerve stimulation. Seventy-two adult patients receiving thiopentone, fentanyl, nitrous oxide, isoflurane anaesthesia and mivacurium 0.15 mg kg-1 were allocated randomly to one of six equal groups according to the type of anticholinesterase and intensity of block at which antagonism was attempted. Groups 1, 3 and 5 received neostigmine 0.07 mg kg-1, while groups 2, 4 and 6 received edrophonium 1 mg kg-1. At the time of administration of antagonist there was no response to PTC in groups 1 and 2, a PTC of 1 or more was detectable in groups 3 and 4 and the first twitch of the TOF (T1) had recovered to 10% in the conventional antagonism groups (5 and 6). The longest clinical duration (CD) values (time from administration of mivacurium to T1 25%) were encountered in groups 1, 5 and 6 and were 17.4 (7.9), 19.7 (3.4) and 21.4 (4.8) min, respectively. CD was reduced significantly in groups 2, 3 and 4 and values were 13.9 (3.5), 13.7 (3.5) and 13.8 (3.3) min, respectively. Recovery indices (RI) (time interval between T1 25% and 75%) were 13.8 (7.3), 6.3 (1.4), 4.6 (1.8), 6.0 (2.1), 3.7 (2.2) and 4.8 (3.1) min in groups 1-6, respectively and was prolonged with neostigmine antagonism at PTC 0 (group 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Dose-response studies of the interaction between mivacurium and suxamethonium.

We have determined the effect of pretreatment with mivacurium on the potency of suxamethonium and the effect of prior administration of suxamethonium on the potency of mivacurium. We studied 100 ASA I or II patients during thiopentone-fentanyl-nitrous oxide-isoflurane anaesthesia. Neuromuscular block was recorded as the evoked thenar mechanomyographic response to train-of-four stimulation of the ulnar nerve (2 Hz at 12-s intervals). Single dose-response curves were determined by probit analysis. Pretreatment with mivacurium had a marked antagonistic effect on the development of subsequent depolarizing block produced by suxamethonium. The dose-response curves for suxamethonium alone and after pretreatment with mivacurium did not deviate from parallelism, but those constructed after mivacurium were shifted significantly to the right (P < 0.0001). The calculated doses producing 50% depression of T1 (ED50) were 86 (95% confidence intervals 83-88) and 217 (208-225) micrograms kg-1 for suxamethonium alone and after mivacurium, respectively. This study also demonstrated that prior administration of suxamethonium did not appear to influence either the slope of the regression lines or the potency of mivacurium. Combining the results of this study with a previous study (mivacurium ED50 = 20.8 (20.3-21.3) micrograms kg-1 during isoflurane-nitrous oxide anaesthesia), we suggest that the potency of mivacurium did not differ from that observed after suxamethonium (17.4 (16.9-17.9) micrograms kg-1).

Adolescent↗

PubMed1994

Thenar muscle blood flow and neuromuscular effects of vecuronium in patients receiving balanced or isoflurane anaesthesia.

We have tested the hypothesis that isoflurane potentiates non-depolarizing neuromuscular block via an increase in muscle blood flow. Anaesthesia was induced with thiopentone 4-5 mg kg-1 in 30 adult male patients of ASA physical status I or II and was maintained with 70% nitrous oxide in oxygen supplemented with either a bolus dose of fentanyl 4 micrograms kg-1 followed by an infusion of 1 microgram kg-1 h-1 (balanced anaesthesia group, n = 15) or 1.1% end-tidal isoflurane (isoflurane group, n = 15). Vecuronium 0.1 mg kg-1 was given for neuromuscular block. The force of contraction of the adductor pollicis of the thumb in response to ulnar nerve stimulation was recorded. Thenar muscle blood flow was measured continuously with a laser Doppler flowmeter. Times required for the first twitch in the train-of-four (T1) to recover to 25%, 75% and 90% of its control value were mean 26.3 (SD 5), 35.3 (10), 43.5 (7) min and 39.2 (15), 53 (12.5), 61.2 (10) min in the balanced anaesthesia and isoflurane groups, respectively (P < 0.01). Recovery index (time between T1 25% and 75%) was prolonged significantly in the isoflurane group. Administration of thiopentone significantly increased thenar muscle blood flow from 2.6 (1.9) and 2.2 (1.5) ml min-1/100 g to 19.2 (14) and 21.7 (16) ml min-1/100 g in the balanced anaesthesia and isoflurane groups, respectively (P < 0.001). The addition of fentanyl (balanced) or isoflurane to the anaesthetic mixture produced further increases in thenar muscle blood flow to reach, respectively, 26.2 (16) and 26.8 (13.6) ml min-1/100 g during steady state anaesthesia. Thenar muscle blood flow was comparable in the two groups throughout the study. We conclude that isoflurane prolonged vecuronium-induced neuromuscular block. This prolongation was not related primarily to increase in muscle blood flow.

Anesthesia, General↗

PubMed1994

Interactions between mivacurium and atracurium.

We have studied the interaction between atracurium and mivacurium. The dose-response relationships of atracurium, mivacurium and their combination were studied in 96 ASA I or II patients during thiopentone-fentanyl-nitrous oxide-isoflurane (1.2% end-tidal) anaesthesia. Neuromuscular block was recorded as the evoked thenar mechanomyographic response to train-of-four stimulation of the ulnar nerve (2 Hz at 12-s intervals). The dose-response curves were determined by probit analysis. Isobolographic and algebraic (fractional) analyses were used to assess quantitatively the combined effect of equipotent doses of atracurium and mivacurium and to define the type of interaction between these drugs. Isobolograms were constructed by plotting single drug ED50 points on the dose co-ordinates and a combined ED50 point in the dose field. The calculated doses producing 50% depression (ED50) of the first twitch height were 50.5 (95% confidence intervals 48.9-52.1) and 20.8 (20.3-21.3) micrograms kg-1 for the atracurium and mivacurium groups, respectively. Isobolographic and fractional analyses of the atracurium-mivacurium combination demonstrated zero interaction (additivism). An additional 26 patients anaesthetized with thiopentone-fentanyl-nitrous oxide-isoflurane were allocated randomly to receive either atracurium 0.5 mg kg-1 (n = 13) or mivacurium 0.15 mg kg-1 (n = 13). Additional maintenance doses of mivacurium 0.1 mg kg-1 were administered to patients in both groups, whenever the first twitch recovered to 10% of control. The duration of the first maintenance dose of mivacurium to 10% recovery of the first twitch was greater (P < 0.0005) after atracurium (25 (21.8-28.5) min) than after mivacurium (14.2 (11.9-16.6) min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Sodium nitroprusside induced hypotension: haemodynamic response and dose requirements during propofol or halothane anaesthesia.

This study was designed to investigate the influence of anaesthesia induced and maintained with propofol on the haemodynamic effects and the dose requirements of SNP during the course of induced hypotension. Twenty-four adult ASA physical status I patients undergoing middle ear surgery were randomly assigned to receive anaesthesia with either morphine, thiopentone, d-tubocurarine, halothane 0.6% end-tidal and N2O 70% in oxygen (group I n = 12), or morphine, propofol, d-tubocurarine, propofol infusion 108 micrograms.kg-1.min-1 and N2O in oxygen (group 2 n = 12). Mean arterial blood pressure (MAP) was reduced to 60-65 mmHg in all patients using a continuous infusion of sodium nitroprusside (SNP) 0.01%. Propofol produced a significant (17%) reduction in the MAP before institution of SNP infusion. This was related to a 24% reduction in the systemic vascular resistance index (SVRI). In the halothane group SVRI was significantly reduced during SNP infusion. Halothane anaesthesia was associated with significant reflex tachycardia in response to SNP induced hypotension. Eight patients in the halothane group (66%) required propranolol 0.5-3 mg to control tachycardia. Propofol anaesthesia attenuated significantly the reflex tachycardia in response to SNP induced hypotension. Two patients in the propofol group (16%) required 0.5 mg propranolol to control reflex tachycardia. The mean SNP dose requirements were 7.25 +/- 1.6 and 2.1 +/- 1.4 micrograms. kg-1.min-1 in the halothane and propofol groups, respectively (P < 0.0001). None of the patients in the two groups developed rebound hypertension following SNP withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

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 micrograms/kg during fentanylthiopental-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) microgram/kg [mean (95% confidence intervals)], respectively. Corresponding ED50 and ED80 values for endrophonium were 84.1 (72.9-96.9) and 233 (215.7-253.3) microgram/kg, respectively. These values corresponded to neostigmine:edrophonium potency ratios of 9.89 (7.4-12.3) and 13.4 (11.8-14.9) for first twitch ED50 and ED80 height, respectively. The calculated doses producing 50% (ED50) recovery of the TOF ratio at 10 min were 18.8 (17.5-20.2) and 271.3 (246.5-298.6) microgram/kg for neostigmine and edrophonium, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Isobolographic and dose-response analysis of the interaction between pipecuronium and vecuronium.

We have studied the neuromuscular effects of pipecuronium, vecuronium and their combination in 130 ASA group I or II patients. Patients were anaesthetized with 0.8% halothane and 60% nitrous oxide in oxygen. Neuromuscular block was recorded as the evoked thenar mechanomyographic response to train-of-four stimulation of the ulnar nerve (2 Hz at 10-s intervals). The dose-response curves were determined by probit analysis. The calculated doses producing 50% depression of the first twitch height were 15.6, 16.9 and 15.0 micrograms kg-1 for the pipecuronium, vecuronium and pipecuronium-vecuronium combination groups, respectively. Isobolographic and algebraic (fractional) analyses were used to assess quantitatively the combined neuromuscular effect of pipecuronium and vecuronium and to define the type of interaction between these drugs. The interaction between pipecuronium and vecuronium was found to be additive.

Adolescent↗

PubMed1993

Dose-response relationships for edrophonium and neostigmine antagonism of mivacurium-induced neuromuscular block.

We have studied the dose-response relationships for neostigmine and edrophonium during antagonism of neuromuscular block induced by mivacurium chloride. Sixty-four ASA group I or II adults were given mivacurium 0.15 mg kg-1 during fentanyl-thiopentone-nitrous oxide-isoflurane anaesthesia. Train-of-four stimulation (TOF) 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-1 or neostigmine 0.005, 0.01, 0.02, or 0.05 mg kg-1 was administered by random allocation. Neuromuscular function in another 16 subjects was allowed to recover spontaneously. Spontaneous recovery from 90% mivacurium block to 95% twitch height and TOF ratio 0.75 occurred within 15 min. This study demonstrated that the dose-response curves for these two drugs for antagonism of neuromuscular block (first twitch and train-of-four ratio) were parallel. The doses of neostigmine required to achieve 50% (ED50) and 70% (ED70) recovery of the first twitch after 10 min were 2 (1.5-2.5) micrograms kg-1 and 4.7 (4.1-5.4) micrograms kg-1 (mean (95% confidence intervals)), respectively. Corresponding ED50 and ED70 values for edrophonium were 2.8 (0.75-10.2) micrograms kg-1 and 9.2 (3.6-23.6) micrograms kg-1, respectively. These values corresponded to neostigmine:edrophonium potency ratios of 1.4 (0.4-2.4) and 1.95 (0.9-2.9) for first twitch ED50 and ED70 height, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Dose-response relationships for edrophonium and neostigmine antagonism of rocuronium bromide (ORG 9426)-induced neuromuscular blockade.

BACKGROUND: Rocuronium 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. METHODS: Sixty-four ASA physical status 1 or 2 adults were given 0.6 mg/kg rocuronium bromide during thiopental-fentanyl-nitrous oxide-isoflurane 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. RESULTS: The 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). CONCLUSIONS: Under 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.

Adult↗

PubMed1991

Neostigmine and edrophonium for reversal of pipecuronium neuromuscular blockade.

Neostigmine 0.06 mg.kg-1 or edrophonium 1 mg.kg-1 were administered to two groups of 15 patients each for antagonism of pipecuronium-induced neuromuscular block at 20% spontaneous recovery of the first twitch (T1) of the train-of-four (TOF) stimulation. The mean onset of action (+/-SEM) of edrophonium (18.1 +/- 2.4 sec) was significantly more rapid (P less than 0.01) than that of neostigmine (47.6 +/- 4 sec), as were the times taken to attain a TOF ratio of 0.25 and 0.5. Nevertheless, the reversal time (time taken from the end of injection of the antagonist until TOF ratio value had reached 0.75) was significantly shorter (P less than 0.01) in the neostigmine than in the edrophonium group (499.3 +/- 62 vs 767 +/- 52 sec respectively). The TOF ratio ten minutes after reversal was greater in the neostigmine group than in the edrophonium group (P less than 0.01), 0.78 +/- 0.02 vs 0.68 +/- 0.02 min respectively. At that time, 33% (5 out of 15) and 80% (12 out of 15) patients failed to be reversed adequately (TOF ratio of 0.75) after neostigmine 0.06 mg.kg-1 and edrophonium 1 mg.kg-1, respectively. Administration of one additional dose (one-third of the initial dose) of the same antagonist resulted in adequate antagonism in the remaining five patients in the neostigmine group and in nine patients in the edrophonium group. Two such doses were required in the remaining three patients in the latter group. The mean total dose of neostigmine and edrophonium employed in this study was 0.067 +/- 0.002 and 1.3 +/- 0.05 mg.kg-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

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.

Adult↗

PubMed1991

Comparative effects of pipecuronium and tubocurarine on plasma concentrations of histamine in humans.

We have examined the effects of a rapid bolus dose of pipecuronium 0.1 mg kg-1 or tubocurarine 0.5 mg kg-1 on plasma histamine concentration, heart rate and arterial pressure in 20 patients (n = 10 in each group). Anaesthesia was induced with thiopentone 6 mg kg-1 i.v. and maintained with 70% nitrous oxide and halothane in oxygen. Neuromuscular blocking drugs were administered 4 min after administration of thiopentone. Venous blood samples were obtained before induction, 1 min after thiopentone and 1, 3 and 5 min after the administration of the neuromuscular blocking drugs. Tubocurarine caused 240% and 210% increases in plasma concentration of histamine at 1 and 3 min, respectively. These changes were significant (P less than 0.05) at 1 min and associated with a decrease in mean arterial pressure and an increase in heart rate. None of the 10 patients receiving pipecuronium had a significant change in plasma concentration of histamine or in haemodynamic variables.

Adult↗