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Biomedical subjects

M Naguib

Publications and source records attributed to M Naguib.

At least 37 records · Page 2Linked to original sources

Response to atracurium and mivacurium in a patient with Charcot-Marie-Tooth disease.

PURPOSE: We studied the neuromuscular effects of both atracurium and mivacurium in a patient with Charcot-Marie-Tooth disease (CMTD) during nitrous oxide-oxygen-alfentanil-propofol anaesthesia. Neuromuscular blockade was monitored electromyographically. Train-of-four stimulation (2 Hz @ 20 sec intervals) was delivered to the ulnar nerve throughout the period of observation. CLINICAL FEATURES: A 17-yr-old man with the diagnosis of CMTD was presented twice for two different orthopaedic surgical procedures. The CMTD had been diagnosed since childhood. Neurological examination revealed distal wasting of the upper and lower limbs, generalised absence of reflexes and decreased sensation in a stocking distribution. In both anaesthetics, induction was carried out with alfentanil and propofol, and anaesthesia was maintained with nitrous oxide in oxygen, alfentanil and propofol infusion. The patient demonstrated a normal response to both atracurium and mivacurium. Onset time and the maximum block attained after atracurium and mivacurium were 240 and 210 sec, and 97% and 99% inhibition of T1 (the first twitch of TOF stimulation), respectively. Recovery of T1 to 10% of the control value occurred 30 and 11.5 min after the administration of atracurium and mivacurium, respectively. The patient made uneventful recoveries after both anaesthetics. CONCLUSION: There was no evidence of prolonged response to atracurium and mivacurium in our patient with CMTD.

Adolescent↗

Central venous pressure from common iliac vein reflects right atrial pressure.

PURPOSE: To determine whether central venous pressure at the common iliac vein reflects right atrial pressure in adult patients. METHODS: In this prospective, non-blinded study 26 mechanically-ventilated adult patients were studied. Simultaneous pressure readings were obtained from the right atrium (TCVP) and the common iliac vein (ACVP). RESULTS: There was a correlation between TCVP and ACVP (r = 0.987; P < 0.0001). The mean difference between TCVP and ACVP was 0.93 mm Hg. And the limits of agreement were: -1.93 to 1.77 mm Hg. CONCLUSION: Venous pressure recorded from the common iliac vein reflects that in the right atrium. Adopting a femoral route for central venous pressure measurement may avoid some of the complications associated with the subclavian route.

Adolescent↗

Perioperative antinociceptive effects of tramadol. A prospective, randomized, double-blind comparison with morphine.

PURPOSE: To compare the efficacy of tramadol and morphine for intra- and postoperative analgesia in patients undergoing laparoscopic cholecystectomy. METHODS: In a prospective, randomized, double-blind study 100 patients were allocated randomly into two groups. Ten minutes before induction of anaesthesia, patients in group 1 received 100 mg tramadol and those in group 2 received 10 mg morphine i.v. Anaesthesia was induced with 5 mg.kg-1 thiopental and was maintained with O2, N2O plus isoflurane with additional doses of tramadol or morphine as decided by the attending anaesthetist. Postoperatively, patients in group 1 and group 2 received tramadol and morphine, respectively, from a patient-controlled analgesia (PCA) device. Pain, analgesic consumption, vital signs and side effects were recorded postoperatively for 24 hr. RESULTS: Intraoperative consumption of tramadol and morphine were 137 +/- 37 and 12.2 +/- 3 mg, respectively. Compared with morphine, patients receiving tramadol had higher blood pressures and required greater mean ETisQ to control haemodynamic variables (P < 0.05). Postoperatively, there were no differences in observer pain score or visual analogue pain score during the first 24 hr between groups except at 30, 45, and 90 min where patients in the tramadol group reported higher pain scores (P < 0.05). The cumulative, 24 hr PCA consumption was 111 +/- 93 and 7.5 +/- 6.6 mg of tramadol and morphine, respectively. CONCLUSIONS: There was no difference between the use of tramadol and morphine to treat pain after laparoscopic cholecystectomy from 90 min after the end of surgery. Morphine was more effective than tramadol as an intraoperative analgesic.

Adolescent↗

Post-pubescent to mature fathers: increase in progeny quality?

In the mouse, offspring born from mature fathers exhibit better behavioural performances (for spontaneous activity in both sex and learning capacity in males) than those born from post-pubescent fathers. These behavioural variations are not accompanied by other obvious modifications. They could correspond to what has been observed in man relating to the results in a psychometric test undergone by male progeny born from very young to mature fathers. These data and those which show a decrease in mental performance in rats and human males born from mature to senescent fathers suggest the participation of some genetic factors in these phenomena.

Aging↗

Comparative clinical pharmacology of rocuronium, cisatracurium, and their combination.

BACKGROUND: The comparative clinical pharmacology of cisatracurium and rocuronium and their combinations has not been reported. In this study, the authors compared the relative potency and the clinical profile and characterized the interaction of both drugs. METHODS: Two hundred twenty adults classified as American Society of Anesthesiologists physical status I and anesthetized with propofol-fentanyl-nitrous oxide were studied. In part 1, the neuromuscular-blocking effects of cisatracurium and rocuronium were assessed after administration of bolus doses of 20-50 microg/kg and 100-300 microg/kg, respectively. In part 2, we compared the time course of 1xED50, 1, 1.5, and 2xED95 doses of both drugs (where ED50 and ED95 are, respectively, the doses producing 50% and 95% depression of the first twitch height [T1]). In part 3, equieffective combinations of both drugs were studied to characterize their interaction. RESULTS: The calculated ED50 values and their 95% confidence intervals were 111 (107-115) and 26.2 (25.8-26.5) microg/kg [corrected] for rocuronium and cisatracurium, respectively. Compared with equipotent doses of cisatracurium, rocuronium had a faster onset, and a faster spontaneous T1 and train-of-four recovery times that were significant except at maximum recovery with the 2xED95 dose. The interaction between rocuronium and cisatracurium was synergistic, and the time profile of the combination group was different from that of the single-dose groups. CONCLUSIONS: Cisatracurium is four to five times more potent than rocuronium. Rocuronium had a faster onset of action, a shorter clinical duration, and a faster spontaneous recovery rate compared with equipotent doses of cisatracurium.

Adult↗

Adverse effects of neuromuscular blockers and their antagonists.

Among all the drugs used for general anaesthesia, neuromuscular blockers appear to play a prominent role in the incidence of severe adverse reactions. It now seems likely that most serious adverse drug reactions occurring during anaesthesia are immunological in type. The frequency of life-threatening anaphylactic or anaphylactoid reactions occurring during anaesthesia has been estimated to be between 1 in 1000 and 1 in 25,000 anaesthetic procedures, with the neuromuscular blockers being involved in 80% of cases. The mortality from such serious reactions is reported to be in the range of 3.4 to 6%. The highly immunogenic drug, suxamethonium chloride (succinylcholine), was found to be the most hazardous agent. Drug-specific immunoglobulin E antibodies to suxamethonium chloride and other neuromuscular blockers have been demonstrated. This sensitivity to neuromuscular blockers seems to be a long-lasting phenomenon. During anaesthesia, the clinical features of an allergic reaction are often masked. Tachycardia and circulatory collapse may be the only signs of an allergic reaction, and they are easily misdiagnosed. Bronchospasm is reported to be present in about 40% of cases. Successful management of these patients includes stabilisation during the acute reaction and avoidance of future reactions. The latter is based on the identification of the causative drug and potentially cross-reacting compounds. The use of suxamethonium chloride is associated with many other adverse effects, such as fasciculations, myalgia, potassium release, changes in the heart rate, increases in intragastric and intraocular pressures, and malignant hyperthermia. Because of the dangers of hyperkalaemic cardiac arrest after suxamethonium chloride administration in children with unrecognised muscular dystrophy, there have now been moves to limit the use of this drug in children. Although neuromuscular blockers are designed to specifically block nicotinic cholinergic receptors at the neuromuscular junction, many bind to muscarinic cholinergic receptors on ganglia and smooth muscle, and alter parasympathetically mediated heart rate and airway calibre. Most benzylisoquinolinium muscle relaxants can induce histamine release, especially when they are administered rapidly, which can lead to disturbances of cardiovascular function. In addition, nondepolarising neuromuscular blockers have been implicated in causing generalised weakness following their long term administration to patients on an intensive care unit. The problem with these adverse drug reactions is their unpredictable nature. Therefore, prompt recognition with appropriate therapy can help to improve the outcome.

Anaphylaxis↗

Adverse effects and drug interactions associated with local and regional anaesthesia.

Systemic and localised adverse effects of local anaesthetic drugs usually occur because of excessive dosage, rapid absorption or inadvertent intravascular injection. Small children are more prone than adults to methaemoglobinaemia, and the combination of sulfonamides and prilocaine, even when correctly administered, should be avoided in this age group. The incidence of true allergy to local anaesthetics is rare. All local anaesthetics can cause CNS toxicity and cardiovascular toxicity if their plasma concentrations are increased by accidental intravenous injection or an absolute overdose. Excitation of the CNS may be manifested by numbness of the tongue and perioral area, and restlessness, which may progress to seizures, respiratory failure and coma. Bupivacaine is the local anaesthetic most frequently associated with seizures. Treatment of CNS toxicity includes maintaining adequate ventilation and oxygenation, and controlling seizures with the administration of thiopental sodium or benzodiazepines. Cardiovascular toxicity generally begins after signs of CNS toxicity have occurred. Bupivacaine and etidocaine appear to be more cardiotoxic than most other commonly used local anaesthetics. Sudden onset of profound bradycardia and asystole during neuraxial blockade is of great concern and the mechanism(s) remains largely unknown. Treatment of cardiovascular toxicity depends on the severity of effects. Cardiac arrest caused by local anaesthetics should be treated with cardiopulmonary resuscitation procedures, but bupivacaine-induced dysrhythmias may be refractory to treatment. Many recent reports of permanent neurological complications involved patients who had received continuous spinal anaesthesia through a microcatheter. Injection of local anaesthetic through microcatheters and possibly small-gauge spinal needles results in poor CSF mixing and accumulation of high concentrations of local anaesthetic in the areas of the lumbosacral nerve roots. In contrast to bupivacaine, the hyperbaric lidocaine (lignocaine) formulation carries a substantial risk of neurotoxicity when given intrathecally. Drugs altering plasma cholinesterase activity have the potential to decrease hydrolysis of ester-type local anaesthetics. Drugs inhibiting hepatic microsomal enzymes, such as cimetidine, may allow the accumulation of unexpectedly high (possibly toxic) blood concentrations of lidocaine. Reduction of hepatic blood flow by drugs or hypotension will decrease the hepatic clearance of amide local anaesthetics. Special caution must be exercised in patients taking digoxin, calcium antagonists and/or beta-blockers.

Adult↗

Adverse effects of neuromuscular blockers and their antagonists.

Among all the drugs used for general anesthesia, neuromuscular blockers appear to play a prominent role in the incidence of severe adverse reactions. It now seems likely that most serious adverse drug reactions occurring during anesthesia are immunological in type. The frequency of life-threatening anaphylactic or anaphylactoid reactions occurring during anesthesia has been estimated to be between 1 in 1000 and 1 in 25,000 anesthetic procedures, with the neuromuscular blockers being involved in 80% of cases. The mortality from such serious reactions is reported to be in the range of 3.4 to 6%. The highly immunogenic drug, suxamethonium chloride (succinylcholine), was found to be the most hazardous agent. Drug-specific immunoglobulin E antibodies to suxamethonium chloride and other neuromuscular blockers have been demonstrated. This sensitivity to neuromuscular blockers seems to be a long-lasting phenomenon. During anesthesia, the clinical features of an allergic reaction are often masked. Tachycardia and circulatory collapse may be the only signs of an allergic reaction, and they are easily misdiagnosed. Bronchospasm is reported to be present in about 40% of cases. Successful management of these patients includes stabilisation during the acute reaction and avoidance of future reactions. The latter is based on the identification of the causative drug and potentially cross-reacting compounds. The use of suxamethonium chloride is associated with many other adverse effects, such as fasciculations, myalgia, potassium release, changes in the heart rate, increases in intragastric and intraocular pressures, and malignant hyperthermia. Because of the dangers of hyperkalemic cardiac arrest suxamethonium chloride administration in children with unrecognised muscular dystrophy, there have now been moves to limit the use of this drug in children. Although neuromuscular blockers are designed to specifically block nicotinic cholinergic receptors at the neuromuscular junction, many bind to muscarinic cholinergic receptors on ganglia and smooth muscle, and alter parasympathetically mediated heart rate and airway calibre. Most benzylisoquinolinium muscle relaxants can induce histamine release, especially when they are administered rapidly, which can lead to disturbances of cardiovascular function. In addition, nondepolarising neuromuscular blockers have been implicated in causing generalised weakness following their long term administration to patients on an intensive care unit. The problem with these adverse drug reactions is their upredictable nature. Therefore, prompt recognition with appropriate therapy can help to improve the outcome.

Anaphylaxis↗

Effects of dyadic vocal interactions on other conspecific receivers in nightingales.

During vocal interactions birds can time their song output so that their songs overlap those of a conspecific. Such overlapping is usually interpreted as a directed signal of arousal or as a signal of readiness to escalate contests. Inevitably, these interactions can often be heard by other conspecifics. To investigate if these conspecifics would perceive and use information derived from listening to others' interactions we conducted playback experiments in the field on male territorial nightingales, Luscinia megarhynchos. We tested whether asymmetric interactions, in which one bird overlaps the song of another individual, influences the behaviour of additional, passive conspecific receivers. To test the influence of song overlapping on a third individual, each subject received one playback treatment in which two intruders were simulated by a dual speaker playback design. Songs broadcast from one loudspeaker overlapped those from the other loudspeaker. Subjects responded more intensely at the side of the overlapper than at the side of the loudspeaker from which the song that was overlapped was broadcast. These differences in response persisted in a second test in which songs of only one of the formerly interacting rivals were played. The results suggest that, even if song overlapping is a signal directed towards the singer whose song is overlapped, this information is perceived and used by additional receivers. Such information on rivals' behaviour during an interaction might help an individual decide which strategies to adopt in possible future interactions with these conspecifics.Copyright 1997 The Association for the Study of Animal Behaviour

Journal Article↗

Comparison of suxamethonium and different combinations of rocuronium and mivacurium for rapid tracheal intubation in children.

The use of suxamethonium in children is associated with undesirable side effects. The synergistic effect of a rocuronium-mivacurium combination can be considered as an acceptable alternative to suxamethonium in clinical practice. The calculated ED50 of the rocuronium-mivacurium mixture was only 62% of the predicted value assuming a purely additive interaction. The use of this combination has not been evaluated in children. In this two-part study, we assessed the intubating conditions and pharmacodynamics of suxamethonium, rocuronium, mivacurium or a rocuronium-mivacurium combinations in children. We studied 120 ASA I children of both sexes, aged 3-10 yr. Children were premedicated with trimeprazine 2 mg kg-1 orally, and received fentanyl 2 micrograms kg-1 and propofol 2 mg kg-1 for induction of anaesthesia. They were allocated randomly to receive one of the following drugs or drug combinations: suxamethonium 1.0 mg kg-1, mivacurium 0.2 mg kg-1, rocuronium 0.6 or 0.9 mg kg-1, mivacurium 0.1 mg kg-1 with rocuronium 0.3 mg kg-1 or mivacurium 0.15 mg kg-1 with rocuronium 0.45 mg kg-1. In part 1, 60 s after administration of the neuromuscular blocking drug or drug combination, tracheal intubation was performed in 60 children by mimicking rapid sequence induction, and intubating conditions were evaluated by a blinded investigator according to a standard score. In part 2, neuromuscular monitoring was established before administration of neuromuscular blocking agent(s) and the time from injection of drug or drug combination until complete ablation of T1 (onset) and recovery of T1 to 25% (duration) were recorded in another 60 children. The frequency of distribution of excellent or good intubating conditions in the higher dose of rocuronium and the combination groups were similar to those in the suxamethonium group, but significantly different (P < 0.05) from those in the mivacurium group. Mean onset time was faster in the suxamethonium (55.1 (SD 11.4) s), rocuronium 0.9 mg kg-1 (70.5 (37.7) s), mivacurium 0.1 mg kg-1 with rocuronium 0.3 mg kg-1 (67 (35.9) s) and mivacurium 0.15 mg kg-1 with rocuronium 0.45 mg kg-1 (55 (26.7) s) groups compared with the mivacurium 0.2 mg kg-1 (116 (26.8) s) and rocuronium 0.6 mg kg-1 (97.9 (29) s) groups. This study demonstrated that the combination of rocuronium 0.45 mg kg-1 and mivacurium 0.15 mg kg-1 could possibly be considered as an acceptable alternative to suxamethonium when rapid sequence induction of anaesthesia is indicated in children because it provides uniform excellent intubating conditions and complete neuromuscular block in < 60 s.

Androstanols↗

Characterization of muscarinic receptor subtypes that mediate antinociception in the rat spinal cord.

UNLABELLED: Spinal cholinergic receptors are involved in mediating antinociceptive effects. To characterize the receptor subtypes modulating nociceptive transmission, we first determined the antinociceptive effects of intrathecally administered muscarinic agonists (McN-A-343 and carbachol) and a cholinesterase inhibitor (neostigmine) in rats. The antagonist potencies of muscarinic antagonists with different preferences for muscarinic receptors [atropine, pirenzepine (M1), methoctramine (M2), and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP; M3)] were then examined for McN-A-343, carbachol, and neostigmine. After determining the time of peak effect for each antagonist, the just maximally effective (JME) dose of each agonist was given in conjunction with one of the several doses of the antagonists. The three agents produced a dose-dependent increase in paw withdrawal latency, with the following 50% effective dose and the following JME doses: neostigmine 6 and 14 nmol, carbachol 29 and 110 nmol, and McN-A-343 354 and 630 nmol. The rank of order of potency (and median infective dose in nanomoles) for the antagonists was: neostigmine = (atropine 14 > 4-DAMP 44 > > methoctramine > 137, and pirenzepine > 236); carbachol = (pirenzepine 0.5 = atropine 0.6 > 4-DAMP 5 > > methoctramine > 137); McN-A-343 = (pirenzepine 0.5 > atropine 3 > 4-DAMP 6 > > methoctramine > 137). Our results suggest that the M1 and possibly the M3 muscarinic receptors mediate spinal antinociception in the rat. IMPLICATIONS: Spinal muscarinic agonists, such as carbachol and the cholinesterase inhibitor neostigmine, induce a potent analgesia in the rat. Using selective receptor antagonists, we have shown that these effects are likely mediated by spinal M1 and/or M3 receptor subtypes.

Analgesics↗

Retrolabyrinthine vestibular nerve section: a current appraisal.

We report our experience (1987-1993) with Meniere's disease patients treated with a retrolabyrinthine vestibular neurectomy. The current literature was reviewed and our results have been compared with those of previous reports. The overall success rate for vertigo relief was 96.7%, with no serious or permanent complications resulting from the procedure. The technical elements of the operation, as they apply to our approach and those of others, have been analyzed, with special attention given to the anatomical features of the region and their influence on success or failure. We conclude that the retrolabyrinthine approach for vestibular nerve section remains a safe and highly successful technique which merits continued use.

Adult↗

Clinically significant drug interactions with general anesthetics--incidence, mechanims and management.

The frequency of adverse drug interactions increases disproportionately with the increase in the number of drugs given to patients. It was shown that 40% of patients given 16 drugs experienced an adverse drug interaction, compared with 5% of patients given fewer than 6 drugs. The magnitude of the drug interaction problem increases substantially in anesthetised patients because of: (i) the increased use of multiple drugs in the preoperative and intraoperative periods; and (ii) the growing population of geriatric patients who, in addition to having diminished drug metabolising capacity, are often prescribed multiplied medications for concomitant medical illness. Drug interactions with volatile and intravenous anesthetics can be divided into those that are pharmacokinetic and pharmacodynamic in nature. Pharmacokinetic interactions occur when the absorption, distribution, metabolism or excretion of a drug is altered by the coadministration of a second drug. Pharmacodynamic interactions involve a change in the pharmacological effect of a drug as a result of the action of second drug at receptor sites.

Anesthetics, Inhalation↗

Prophylactic antiemetic therapy with ondansetron, tropisetron, granisetron and metoclopramide in patients undergoing laparoscopic cholecystectomy: a randomized, double-blind comparison with placebo.

PURPOSE: Postoperative nausea and vomiting (PONV) is a distressing adverse effect of general anaesthesia. The aim of the current study was to compare the antiemetic activity of different 5-hydroxytryptamine3 receptor antagonists with that of metoclopramide and placebo. METHODS: In a prospective, randomized, double-blind study we have compared the antiemetic activity of the prophylactic administration of ondansetron 4 mg, tropisetron 5 mg and granisetron 3 mg with that of metoclopramide 10 mg and placebo in 132 patients undergoing laparoscopic cholecystectomy. All study drugs and placebo were given as a short iv infusion ten minutes before the induction of anaesthesia. Perioperative anaesthetic care was standardized in all patients. Nausea and vomiting were assessed by direct questioning of the patient at 1, 4, 9, 12, 18 and 24 hr after recovery from anaesthesia. If patients experienced nausea and/or vomiting, rescue antiemetic treatment (metoclopramide 10 mg iv) was administered. RESULTS: For the 24-hr recovery period after surgery, the percentages of emesis-free patients were 65.5%, 52%, 48%, 29.2% and 27.6% in the ondansetron, granisetron, tropisetron, metoclopramide and placebo groups, respectively. Prophylactic antiemetic treatment with ondansetron resulted in a lower incidence (P = 0.02) of PONV than with metoclopramide or placebo. The times at which rescue antiemetic was first received were longer (P < 0.01) in ondansetron group than in the placebo and metoclopramide groups. There were no statistical differences between ondansetron, tropisetron and granisetron groups. CONCLUSIONS: Ondansetron, when given prophylactically resulted in a significantly lower incidence of PONV than metoclopramide and placebo. Metoclopramide was ineffective.

Adult↗

Multivariate determinants of the need for postoperative ventilation in myasthenia gravis.

PURPOSE: Following transsternal thymectomy, up to 50% of patients may require postoperative ventilation. The aim of this study was to identify the variables most useful in predicting the myasthenic patient who needs postoperative mechanical ventilation. METHODS: We applied multivariate discriminant analysis to preoperative physical, historical, laboratory and intraoperative data of 51 myasthenic patients who underwent transcervical-transsternal thymectomy to select those variables most useful in predicting the postoperative need for mechanical ventilation. The receiver operating characteristic (ROC) curve was also used to describe the discrimination abilities and to explore the trade-offs between sensitivity and specificity of the model. RESULTS: Discriminant analysis identified seven risk factors that correlated with the need for postoperative ventilation: FVC, FEF25-75%, MEF50% and their percentages of the predicted values, as well as, sex. The model correctly predicted the actual ventilatory outcome in 88.2% of patients. The area under the ROC curve verified that our model correctly predicted the actual ventilatory outcome with a probability of 88.2%. CONCLUSIONS: This model can be used for predicting the need for postoperative mechanical ventilation in myasthenia gravis patients.

Adolescent↗

Edrophonium and human plasma cholinesterase combination for antagonism of mivacurium-induced neuromuscular block.

We have compared the reversal characteristics of mivacurium after administration of an edrophonium-plasma cholinesterase (PCHE) combination with that produced by each antagonist alone. Forty ASA I adults were given mivacurium 0.15 mg kg-1 during fentanyl-thiopentone-nitrous oxide-isoflurane anaesthesia. TOF stimulation was applied to the ulnar nerve every 12 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height (T1) reached 10% of its initial control value, patients were allocated randomly to one of four groups (n = 10 in each). Neuromuscular function in patients in group 1 (control group) was allowed to recover spontaneously. Patients in groups 2-4, respectively, received edrophonium 1 mg kg-1 (group ED), exogenous PCHE equivalent to activity present in 25 ml kg-1 of human plasma (group PCHE) or edrophonium 1 mg kg-1 with exogenous human PCHE equivalent to the activity present in 25 ml kg-1 of human plasma (combination group). The time to attain a TOF ratio of 0.75 in the combination group was 4.6 (SD 0.9) min. This was shorter (P < 0.01) than that observed in patients in the control (16.8 (3.3) min), ED (8.9 (3.6) min) and PCHE (9.3 (1.6) min) groups. There was no difference in recovery indices between groups ED and PCHE. We have demonstrated that the edrophonium-PCHE combination significantly accelerated recovery of mivacurium-induced block compared with that observed with the use of individual antagonists.

Adolescent↗