Cardiac implications of amlodipine-dantrolene combinations.

Purpose: Cardiac disorders, cardiac arrest and ventricular fibrillation in the most severe cases, have been observed after the administration of dantrolene to patients treated by verapamil for coronary artery disease. This study was designed to examine the interaction of dantrolene with amlodipine, a dihydropyridine.

Methods: In 12 anaesthetized, open-chest pigs, the effects of the interaction have been studied on heart rate, atrioventricular conduction, monophasic action potential duration, intraventricular conduction time, left ventricular dP/dt max and mean blood pressure.

Bupivacaine hastens the ischemia-induced decrease of the electrical ventricular fibrillation threshold.

Myocardial ischemia sensitizes the cardiotoxic effects of bupivacaine, especially the propensity to ventricular fibrillation. To investigate this sensitization and to elucidate its mechanism, the influence of bupivacaine alone, or associated with ischemia, was studied on electrical fibrillation threshold in anesthetized, open chest pigs. Determination of fibrillation threshold was performed with impulses of 100 ms duration at the rate of 180 bpm, in the absence of ischemia and at the end of increasing periods of ischemia (30, 60, 120, 180 s) obtained by complete occlusion of the left anterior descending coronary artery close to its origin.

[Surgery for epidermolysis bullosa in children: value of the association of inhalation anesthesia and locoregional anesthesia].

Due to the cutaneous and mucosal fragility associated with epidermolysis bullosa, this disease is a source of various practical problems for the anaesthesiologist concerning the surgical posture, the monitoring of vital functions, the airways control and the vascular access, as all these procedures may worsen, sometimes dramatically, the lesions in these young patients, still in a precarious health state. Basing on published studies and their own experience, the authors have used in these patients a combined locoregional and general anaesthesia. The latter was obtained with isoflurane, administered in the non intubated and spontaneously breathing patient through a closed surgical isolation container (Vi-Drape), including the patient's head and ventilated with a ventilator generating a PEEP for long procedures.

Enhancement by ischemia of the risk of cardiac disorders, especially fibrillation, in regional anesthesia with bupivacaine.

The impairment of intraventricular conduction by bupivacaine may result in reentrant arrhythmias including ventricular fibrillation. The concentrations responsible for serious accidents are high (5.0 to 8.

[Gastroesophageal reflux with combined caudal and halothane anesthesia in children].

Sixteen children, aged 2 to 5 years and ranked ASA 1, were included in this study assessing gastro-oesophageal reflux occurring under halothane anaesthesia, before and during, caudal anaesthesia. They were scheduled for surgery below the umbilicus lasting 1 to 5 h. After premedication with oral hydroxyzine (2 mg.

Adverse interaction between bupivacaine and halothane on ventricular contractile force and intraventricular conduction in the dog.

Regional anesthesia with bupivacaine in pediatric patients is often accompanied by light levels of halothane general anesthesia. To determine the potential cardiotoxicity of these two drugs when used together, we defined the interaction between moderate plasma bupivacaine concentrations (1270-1760 ng/mL) and halothane (end-tidal concentrations, 0.5%-1.

Possible role of drug interactions in bupivacaine-induced problems related to intraventricular conduction disorders.

Clinically, bupivacaine has depressant effects on intraventricular conduction that may lead to serious atrioventricular blocks or reentrant arrhythmias at plasma levels below those required to produce these effects experimentally (2-3 micrograms/ml instead of 8-10 micrograms/ml). The difference could be due to drugs present in the blood at the time of regional anesthesia that similarly inhibit conduction. This hypothesis was examined in 30 anesthesized, closed-chest dogs by measuring conduction time in the ventricular contractile fibers as well as effective refractory period under pacing at a constant, relatively high (180 beats/minute) rate.

Ventricular and atrial electrophysiological effects of a IC antiarrhythmic drug, cibenzoline, in the innervated dog heart. Role of sodium and calcium channels.

The effects of cibenzoline, rightly known as a sodium channel inhibitor (class IC antiarrhythmic drug), were investigated in anaesthetized, closed-chest dogs, on conduction in the contractile fibres, ventricular and atrial, the His-Purkinje system and the atrioventricular node. In ventricular muscle, conduction time was measured between base and apex by two endocavitary electrodes. The other conduction times were obtained from the recording of the His bundle potentials.

Potentiation by mild hypothermia of ventricular conduction disturbances and reentrant arrhythmias induced by bupivacaine in dogs.

High concentrations of bupivacaine and profound hypothermia individually cause intraventricular conduction disturbances and reentrant arrhythmias. The effects of the combination of relatively low concentrations of bupivacaine and mild hypothermia are unknown and are the subject of this study. Three groups (n = 10-12) of dogs anesthetized with thiopental-chloralose were treated as follows: group 1, bupivacaine + hypothermia; group 2, bupivacaine alone; group 3, hypothermia alone.

Effects of isoproterenol and propranolol on pharmacologically induced depression of intraventricular conduction.

The cardiac adrenergic system is known to have practically no influence on conduction velocity in the ventricles under normal conditions. The effects of isoproterenol and propranolol were investigated on depression of intraventricular conduction induced by a class IC antiarrhythmic drug, cibenzoline, in anaesthetized, closed-chest dogs. In addition to electrocardiogram for measurement of QRS duration in sinus rhythm, conduction time was measured in the ventricular contractile tissue between an electrode advanced to the apex and a pacing electrode near the base, at 400- and 200-ms pacing periods.

[Caudal anesthesia in pediatric surgery. Pharmacokinetic study and clinical significance].

In 1987, 758 caudal anaesthesia allowed the execution of 41% of all our department's operations. Urological, genital, inguinal and lower limbs surgery were the most frequent. The injection into the extradural space through the hiatus sacralis always included the mixture of lidocaine with bupivacaine to speed up the beginning of the operation.

[Locoregional anesthesia in pediatrics].

Local anaesthesia may consist of a sensitive and a motor blockade. It is essentially used in human clinic for the sensitive blockade which is induced. All techniques or nearly are possible in regional anaesthesia for children if they are practised with discernment by a physician accustomed to the same techniques in adults.

Haemodynamic effects of high plasma concentrations of bupivacaine in the dog.

The threshold concentrations responsible for circulatory collapse were experimentally investigated by intravenously infusing the drug at high rates (0.2 and 0.3 mg kg-1 min-1 over 20 min, and 0.

[Systemic toxicity of local anesthetics. Pharmacokinetic and pharmacodynamic factors].

Local anaesthetics can have systemic adverse effects, mostly affecting the central nervous system and the heart. The physicochemical characteristics of the different local anaesthetics are recalled, for they determine the relationship between structure, activity and toxicity. The pharmacokinetic factors involved in the toxic effects of local anaesthetics, whether the drug is given in a single extravascular dose or, accidentally, within a blood vessel, are discussed.

[Phenoperidine: pharmacology and use in pediatric resuscitation].

Phenoperidine is mainly metabolised in the liver, and has a biliary and urinary elimination. Because its analgesic effects are fast and prolonged, this drug is often used in pediatric intensive care units, due to its interesting pharmacologic properties (mild cardiac and respiratory depression).

[Coagulopathy and anemia caused by anticonvulsants].

Long-term antiepileptic polytherapy regularly induces some slight impairment of haemostasis without clinical manifestations, but serious clinical disorders may appear, even in the absence of over-dosage. In the case reported here the patient was undergoing surgery for correction of scoliosis. Preoperative laboratory tests only showed a slight decrease of fibrinogen and a moderate lengthening of thrombin time; there was no anaemia.

Electrophysiological study in the dog of the risk of cardiac toxicity of bupivacaine.

The risk of toxic effects on the heart of bupivacaine following several kinds of locoregional anaesthesia has been investigated in the dog in situ heart by determining conduction time and effective refractory period in the various parts of the conduction system and the ventricular muscle, as well as the discharge rate of the sinus node. Bupivacaine, i.v.

[Diaphragmatic hernia: the role of perioperative resuscitation].

Twenty-nine newborn infants with diaphragmatic hernia have been received in a neonatal intensive care unit over a seven year period. In three cases, clinical signs appeared after the first day: they all survived. Six infants died before surgery: five of them had major pulmonary hypoplasia.

Protection against ventricular and atrial fibrillation by sotalol.

Sotalol is not only a beta blocker but a class III antiarrhythmic drug. Its possible antifibrillatory activity was therefore investigated in both the ventricles and atria of dog heart in situ, since vulnerability to fibrillation is not the same in both these parts of the myocardium. Fibrillation threshold was measured concurrently with the duration and amplitude of monophasic action potential, the effective refractory period, the conduction time in the contractile fibres, and after fibrillation had been triggered the fibrillation rate.

[Peranesthetic monitoring of ventilation in children: value of capnometry].

Continuous measurement of the end-expiratory partial pressure of carbon dioxide (PETCO2) during anaesthesia has been proposed for non-invasive monitoring of arterial PCO2 (PaCO2). The values and the stability of the difference (PaCO2-PETCO2) during anaesthesia were studied for two ventilatory settings in eight children with healthy lungs and normal cardiac function undergoing minor surgery. PaCO2 values were all within a physiological range (30.