ABSTRACT
The onset and time course of action of rocuronium in normal children and children receiving anticonvulsant drugs for prolonged periods was characterized. A single bolus dose of 0.6 mg.kg-1 rocuronium was administered i.v. to seven nonepileptic patients on no medication, and eight patients on chronic anticonvulsant therapy consisting of either phenytoin, carbamazepine, or both who were age and weight matched. Neuromuscular transmission was monitored by the evoked compound electromyography of the thenar muscles using train of four stimulation every 20 s. Recovery times of the first twitch to 10%, 25%, 50%, 75% and 100% of baseline values and recovery index were obtained. The onset times were 1.05+/-0.5 and 1.41+/-0.5 min for the control and anticonvulsant groups respectively and were not significantly different. Children receiving chronic anticonvulsant therapy had significantly shorter recovery index than the control group (control 10.4+/-5.1 min, anticonvulsant 4.8+/-1.7 min, P<0.05). Furthermore, the duration of recovery to 10%, 50%, 75% and 100% of baseline T1 values was less in the anticonvulsant drug group. Our data confirm resistance to rocuronium in children on chronic anticonvulsant drugs.
Subject(s)
Androstanols/administration & dosage , Anticonvulsants/therapeutic use , Neuromuscular Blockade , Neuromuscular Nondepolarizing Agents/administration & dosage , Analysis of Variance , Anesthesia Recovery Period , Carbamazepine/therapeutic use , Case-Control Studies , Child , Drug Interactions , Electric Stimulation , Electromyography/drug effects , Epilepsy/drug therapy , Evoked Potentials, Motor/drug effects , Humans , Injections, Intravenous , Muscle Contraction/drug effects , Muscle, Skeletal/innervation , Neuromuscular Junction/drug effects , Phenytoin/therapeutic use , Rocuronium , Synaptic Transmission/drug effects , Thumb/innervation , Time FactorsABSTRACT
BACKGROUND: Cardiovascular stability is an important prerequisite for any new volatile anesthetic. We compared echocardiographically derived indices of myocardial contractility during inhalation induction with sevoflurane and halothane in children. METHODS: Twenty children were randomized to receive either halothane or sevoflurane for inhalation induction of anesthesia. No preoperative medications were given. Myocardial contractility was evaluated at baseline and at sevoflurane and halothane end-tidal concentrations of 1.0 minimum alveolar concentration (MAC) and 1.5 MAC. RESULTS: There were no differences between groups in patient age, sex, physical status, weight, or height. Equilibration times and MAC multiples of sevoflurane and halothane were comparable. Vital signs remained stable throughout the study. Left ventricular end-systolic meridional wall stress increased with halothane but remained unchanged with sevoflurane. Systemic vascular resistance decreased from baseline to 1 MAC and 1.5 MAC with sevoflurane. Halothane depressed contractility as assessed by the stress-velocity index and stress-shortening index, whereas contractility remained within normal limits with sevoflurane. Total minute stress and normalized total mechanical energy expenditure, measures of myocardial oxygen consumption, did not change with either agent. CONCLUSIONS: Myocardial contractility was decreased less during inhalation induction of anesthesia with sevoflurane compared with halothane in children. Although the induction of anesthesia with sevoflurane or halothane was equally well tolerated, the preservation of myocardial contractility with sevoflurane makes it an attractive alternative for inducing anesthesia in children.
Subject(s)
Anesthesia, Inhalation , Anesthetics, Inhalation/pharmacology , Ethers/pharmacology , Halothane/pharmacology , Methyl Ethers , Myocardial Contraction/drug effects , Child , Child, Preschool , Echocardiography , Female , Hemodynamics/drug effects , Humans , Male , Random Allocation , SevofluraneABSTRACT
Major advances have occurred in the management of MH since this disorder was first described. Despite the initially high mortality, deaths secondary to MH have dramatically decreased over the past 15 years, which is due in large part to the discovery of efficacious therapy. It is also a result of ever-increasing awareness and appreciation of the syndrome by physicians, other health care providers, and patients. Research has provided many answers to questions about the pathologic mechanisms of this disorder, and an animal model exists for testing new therapies; however, many questions remain. It is hoped that future investigations such as advances in genetic mapping may provide a specific, noninvasive method of predictive testing. It is possible that a complete understanding of MH and its mechanisms could teach us more about the ways anesthetic agents work. For now, identifying individuals at risk, rigorously avoiding exposure to potential anesthetic triggering agents in MH-susceptible patients, and promptly recognizing and treating unexpected MH episodes are the primary means of reducing morbidity and mortality from MH. Interested and informed clinicians and families are the patient's best allies against MH.
Subject(s)
Anesthesia/methods , Malignant Hyperthermia/diagnosis , Malignant Hyperthermia/therapy , Adolescent , Adult , Biopsy , Caffeine , Child , Child, Preschool , Clinical Protocols , Counseling , Halothane , Humans , Male , Malignant Hyperthermia/epidemiology , Malignant Hyperthermia/physiopathology , Patient Education as Topic , Risk FactorsABSTRACT
Aminoglycosides in aquarium water produce a temporary impairment of sensitivity in the lateral line organ of fish. If Ca++ ions are supplied at the same time, the impairment in lateral line sensitivity can be alleviated in a dose-dependent manner. This mechanism appears to be based on competitive antagonism.
Subject(s)
Auditory Threshold/drug effects , Calcium Chloride/pharmacology , Fishes/physiology , Hair Cells, Auditory/drug effects , Models, Biological , Neomycin/toxicity , Animals , Auditory Threshold/physiology , Calcium Chloride/administration & dosage , Dose-Response Relationship, Drug , Female , Hair Cells, Auditory/physiology , Male , Neomycin/antagonists & inhibitorsABSTRACT
The effect of neomycin and streptomycin on the lateral line system of fishes was studied behaviourally by testing the animal's ability to localize a wave source. Increasing doses of both substances produce increasing loss of lateral line reactions, up to total inexcitability. The toxicity of both antibiotics was very similar. Lateral line sensitivity recovered 1-3 days after antibiotic removal.
Subject(s)
Ear, Inner/drug effects , Neomycin/toxicity , Streptomycin/toxicity , Animals , Cyprinodontiformes , Ear, Inner/physiopathology , Female , Hair Cells, Auditory/drug effects , Hair Cells, Auditory/physiology , Male , Sound Localization/drug effects , Sound Localization/physiologyABSTRACT
The effect of neomycin and streptomycin on the lateral line system of fishes was studied behaviourally by testing the animal's ability to localize a wave source. Increasing doses of both substances produce increasing loss of lateral line reactions, up to total inexcitability. The toxicity of both antibiotics was very similar. Lateral line sensitivity recovered 1-3 days after antibiotic removal.