Adequate Muscle Relaxation Research Articles

Electroconvulsive Therapy Complicated by Insecticide Ingestion

The patient attempted suicide, first with a flurazepam overdose, then with clonazepam. Nine days prior to his admission with us, the patient attempted suicide by drinking dimpylate (Diazenon), a commonly available household insecticide, for which he was hospitalized. We chose to treat the patient with electroconvulsive therapy. After preoxygenation, in accordance with proscribed standards, a defasciculating dose of D-tubocurarine, 3 mg was given intravenously followed by methohexital 60 mg and succinylcholine, 120 mg, given intravenously 2 minutes later. Assisted ventilation was required for 1 hour before neuromuscular blockade was completely reversed. Because of the prolonged effect of succinylcholine, a pseudocholinesterase deficiency was suspected. It was concluded that the patient's prolonged response to succinylcholine resulted from the ingestion of dimpylate, which is a pseudocholinesterase inhibitor. For subsequent ECT treatments, the patient required only 20-30 mg of succinylcholine for adequate muscle relaxation. Serial measurements of pseudocholinesterase revealed an almost normal level, 6.8 IU/liter, by the time of discharge 3 weeks later

Studies on Lorazepam as a Premedicant for Thiopental Anaesthesia in the Dog

Four mg of lorazepam was given intravenously 5 min prior to thiopental anaesthesia in 5 clinically healthy dogs weighing 14 +/- 2 kg and aged about 10-12 months. Animals required only 7.0 +/- 1.5 ml of 5% thiopental sodium to achieve surgical anaesthesia which lasted about 30.4 +/- 3.3 minutes. There was adequate muscle relaxation and loss of pedal and palpebral reflexes. Five min after administration of lorazepam, there was no appreciable change in various cardiopulmonary dynamics. However, there was moderate arterial hypertension, tachycardia and arterial hypoxemia 15 min after the onset of the thiopental anaesthesia. There was no respiratory depression. The lorazepam-thiopental combination was also attempted in 16 clinical cases varying from repair of fractures of long bones (9), mammary tumour (2), ear haematoma (1), ear cropping (1), tail gangrene (2) and rectal prolapse (1). This combination of anaesthesia proved extremely useful for orthopaedic surgery as the muscle relaxation was adequate and reduction of the fractured ends was comparatively easier.

Rib cage and diaphragm-abdomen compliance in humans: effects of age and posture.

The influence of age and posture on compliance of the rib cage (Crc) and diaphragm-abdomen (Cab) compartments of the chest wall was studied in 61 healthy adults (33 men, 28 women) aged 24-75 yr. Chest wall compliance (Cw) was measured by the weighted spirometer technique; Crc and Cab were derived from the slope of the relaxation line of the thoracoabdominal system obtained with two pairs of linearized magnetometers. While Cw was being measured, we monitored electrical activity of the abdominal external oblique muscle with a concentric needle electrode and thoracoabdominal configuration. In 52 subjects, the electromyogram did not show any abdominal muscle activity and the end-expiratory level never departed from the relaxed thoracoabdominal configuration, thus suggesting adequate respiratory muscle relaxation. Aging was associated with significant decreases in Crc and Cab. In the upright posture Crc decreased from 0.164 +/- 0.041 (mean +/- SD) l/cmH2O in the younger subjects (24-39 yr) to 0.114 +/- 0.027 l/cmH2O in the older subjects (55-75 yr). Cab concomitantly fell from 0.032 +/- 0.012 l/cmH2O to 0.020 +/- 0.007 l/cmH2O. These reductions were statistically significant (P less than 0.05-0.01) and were also present in the supine posture. Shifting from the seated to the supine posture did not cause any significant change in Cw but was invariably associated with a decrease in Crc and an increase in Cab.(ABSTRACT TRUNCATED AT 250 WORDS)

Pipecuronium Bromide (Arduan)—A New Long-acting Non-depolarizing Neuromuscular Blocking Drug

Summary In many respects, pipecuronium is similar to pancuronium. Its neuromuscular blocking potency is equal to or slightly greater than that of pancuronium and, consequently, its routine use in clinical practice should follow the existing general pattern for pancuronium. A dose of 0.05 mg/kg following intubation with suxamethonium will provide adequate muscle relaxation for 40–50 minutes. For intubation, however, the dose should be increased to 0.08–0.1 mg/kg which will give satisfactory intubating conditions in 2.5–3 minutes and adequate surgical relaxation for 80–120 minutes. As with pancuronium, cumulative effects after repeated doses and potentiation of inhalation anaesthetic agents—particularly by enflurane—can be expected. Therefore, maintenance doses should be one-quarter of the initial dose or less, and should be administered at 40–50-minute or 60–70-minute intervals following the use of low (0.05 mg/kg) or high (0.1 mg/kg) initial doses, respectively. When using potent inhalation anaesthetics, the size of maintenance doses should be decreased further (one-fifth to one-sixth of the initial dose) or the time interval between them prolonged. Pipecuronium appears to be free from histamine-releasing properties. The most important advantage of this compound in comparison with other long-acting drugs like pancuronium or alcuronium is that it is devoid of circulatory effects. These properties, if confirmed in widespread clinical use, will make pipecuronium the drug of choice for long operations, particularly in patients with cardiovascular disease. It should not, however, by used in patients with renal or hepatic disease until more information on its pharmacokinetics in such patients becomes available. The availability of pipecuronium bromide will not remain limited to eastern European countries for long. Recently, Gedeon Richter Ltd (Hungary) licensed Organon Teknika (Belgium) to manufacture and market pipecuronium in western Europe, the USA and in a number of other countries. The ampoules currently used contain 4 mg of the freeze-dried agent that should be dissolved in 2 ml solvent. Arduan should be stored in the refrigerator at 4°C and should be used shortly after dissolving the powder.

Chest wall stiffness in patients with chronic respiratory muscle weakness.

Using the weighted spirometer technique we studied chest wall compliance (Cw) in 16 nonobese patients with chronic weakness of the respiratory muscles and 20 healthy control subjects. In order to evaluate the validity of the technique, while Cw was being measured, we monitored thoracoabdominal configuration with 2 pairs of linearized magnetometers and electrical activity of the external oblique with a concentric needle electrode in 3 healthy subjects and 4 patients; in addition, we recorded in 3 subjects the electrical activity from the intercostal muscles and diaphragm throughout the procedure. The method was reproducible within 5.8% and provided Cw values that compared well with those yielded by the relaxation technique. In each subject, the weight-induced shifts in end-expiratory lung volume showed a very good linear correlation with the changes in transrespiratory pressure at end-expiration (r greater than or equal to 0.91). In addition, in none of the subjects tested did the electromyograms reveal any intercostal, diaphragmatic, or abdominal muscle activity at end-expiration, nor did the end-expiratory level ever show a significant departure from the relaxed thoracoabdominal configuration, thus suggesting adequate respiratory muscle relaxation. The reduction in inspiratory muscle force in the patients ranged from 17 to 94% of predicted (mean +/- SE, 43 +/- 6). The decrease in vital capacity, total lung capacity, and functional residual capacity averaged 59, 34, and 15% of predicted, respectively. Both the patient and the control groups showed a large interindividual variability regarding Cw. It varied from 0.117 to 0.258 L/cm H2O (mean +/- SE, 0.162 +/- 0.012) in the patients and from 0.163 to 0.366 L/cm H2O (mean +/- SE, 0.248 +/- 0.013) in the healthy subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Systemic vascular responses to atracurium during enflurane-nitrous-oxide anesthesia in humans.

Systemic circulatory responses to atracurium (0.2 and 0.4 mg/kg) were studied in 15 healthy (ASA I or II) adult patients during enflurane (1.0 to 1.25% inspired) and nitrous oxide (70% inspired) anesthesia. All patients were premedicated with intramuscular morphine (10-15 mg) and glycopyrrolate (0.2 mg). Compared with control measurements during enflurane-nitrous oxide anesthesia, heart rate, cardiac and stroke index, central venous pressure, and systemic mean arterial pressure remained unchanged at 2, 5, and 10 min after administration of both doses of atracurium. Systemic vascular resistance was minimally decreased (7% compared to control) (0.01 less than P less than 0.05) at 10 min following both doses of atracurium. No patient demonstrated a decrease in systemic mean arterial pressure greater than 6 mmHg. The authors conclude that atracurium in doses which produce adequate skeletal muscle relaxation during steady-state enflurane anesthesia produces no clinically significant alteration in hemodynamic variables.

Anesthesia for Thymectomy in Myasthenis Gravis - A case report

Anesthesiologists are called upon to undertaker, or to assist in the management of severe respiratory and circulatory or other surgical procedures to be performed on myasthenic subjects. Consequently the well-trained anesthesiologists must be sufficiently familiar with the diagnosis and teatment of myasthenia gravis to carry on the therapy. A case of anesthesia for thymectomy in myasthe gravis was experienced. During operation, 0.1% succinylcholine in dripp method was given for adequate muscle relaxation and no respiratory problems were encountered postoperatively.

USE OF ATRACURIUM DURING GENERAL SURGERY MONITORED BY THE TRAIN-OF-FOUR STIMULI

The use of atracurium in 25 patients undergoing general surgical procedures is described, neuromuscular function being monitored by the "train-of-four" stimuli. An initial dose of atracurium 0.5 mg kg-1 proved to be clinically acceptable, giving good conditions for endotracheal intubation and adequate muscle relaxation for about 40 min. Comparison of the results with those from 15 patients given suxamethonium 50 mg showed that atracurium in this dosage took longer to produce complete ablation of the twitch responses but that it lasted longer (about 40 min). Incremental doses of atracurium (of 0.2 mg kg-1) gave relaxation for about 30 min and there was no evidence of a cumulative effect. Reversal of the neuromuscular block with neostigmine was prompt and adequate. Using simple clinical means no evidence of an important change in heart rate or arterial pressure was found. There were no adverse reactions to the drug.

Intérêt d'un mélange ternaire d'anesthésiques locaux dans l'anesthésie péridurale pour opération césarienne urgente: dans 125 observations

125 caesarean operations are conducted under peridural anaesthesia with a mixture of local anaesthetics containing per milliliter : 2.5 mg of bupivacaine, 2.5 mg of etidocaine, 12.5 mg of lidocaine, and 5.10 −6 epinephrine. The dose injected is 23.37 ± 1.98 ml, the volume necessary for blocking a metamer being 1.18 ± 0.10 ml/segment. Satisfactory analgesia is obtained in 119 cases (95.2 p. cent), with adequate muscle relaxation in all cases. Block anaesthesia occurrs after 5.81 ± 0.67 min, last 197 ± 62 min, and enable incision after 8.80 ± 2.55 min with extraction of the infant after 13.72 ± 2.85 min in 25 « extremely urgentcases. Apgar is 8.98 ± 1.62 after one minute and 9.68 ± 1.31 after five minutes. These results proove that under perfect circumstances it is possible to get out the baby in about ten minutes.

Pancuronium Pharmacokinetics in Patients with Liver Cirrhosis

The serum and urinary concentrations of pancuronium were measured in 14 surgical patients with cirrhosis and 12 patients free from liver disease undergoing abdominal surgery. A two-compartment open model was used in the pharmacokinetic analysis of the data. A two-fold increase in both the distribution half-life (T½α) from 11 min to 24 min and in the elimination half-life (T½β) from 114 min to 208 min was observed in patients with cirrhosis. In these individuals, the total apparent volume of distribution of pancuronium was increased by 50%. Plasma clearance of pancuronium was decreased by 22%. No significant difference was found in the urinary excretion and biotransformation pattern of pancuronium. These results suggest that there is a risk of prolonged duration of action of pancuronium in patients with cirrhosis. In these patients, the initial dose to achieve adequate muscle relaxation is high and simultaneously there is slow disappearance of pancuronium from plasma. These alterations are mainly a consequence of the increase in the distribution volume of pancuronium in patients with cirrhosis.

PANCURONIUM PHARMACOKINETICS IN PATIENTS WITH LIVER CIRRHOSIS

The serum and urinary concentrations of pancuronium were measured in 14 surgical patients with cirrhosis and 12 patients free from liver disease undergoing abdominal surgery. A two-compartment open model was used in the pharmacokinetic analysis of the data. A two-fold increase in both the distribution half-life (T 1/2 alpha) from 11 min to 24 min and in the elimination half-life (T 1/2 beta) from 114 min to 208 min was observed in patients with cirrhosis. In these individuals, the total apparent volume of distribution of pancuronium was increased by 50%. Plasma clearance of pancuronium was decreased by 22%. No significant difference was found in the urinary excretion and biotransformation pattern of pancuronium. These results suggest that there is a risk of prolonged duration of action of pancuronium in patients with cirrhosis. In these patients, the initial dose to achieve adequate muscle relaxation is high and simultaneously there is slow disappearance of pancuronium from plasma. These alterations are mainly a consequence of the increase in the distribution volume of pancuronium in patients with cirrhosis.

CLINICAL IMPRESSIONS OF ENFLURANE

Enflurane was used in 150 non-selected patients and was found to be a most satisfactory inhalation anaesthetic. Induction and recovery times were rapid and these characteristics, together with its rather pleasant smell, made it readily acceptable to the patient. Although such features suggest that it would be an ideal agent for children, very high concentrations of enflurane were required to produce adequate anaesthesia in infants and small children. Normal sinus rhythm continued following the injection of adrenaline during enflurane anaesthesia and adequate muscle relaxation was obtained for lower abdominal surgery. The degree of metabolic breakdown of enflurane is considerably less than with other inhalation agents and, if this is reflected in terms of minimal renal and hepatic toxicity, there is every reason to believe that enflurane may be preferable to the volatile anaesthetics currently in use.

Clinical Evaluation of Etidocaine in Continuous Caudal Analgesia for Pelvic Floor Repair and Post-Operative Pain Relief

A randomized double-blind trial compared 1-0% etidocaine and 1-5% lignocaine (both with 1/200,000 adrenaline), for caudal anaesthesia for pelvic floor repair. Etidocaine was highly effective for the surgical procedure, with rapid onset of action, adequate muscle relaxation and longer duration of action. Its use for post-operative analgesia may be hindered by the concomitant immobilization of the legs. The problem of tachyphylaxis with etidocaine needs further investigation.

The use of meperidine in peroral endoscopies.

The growing number of peroral endoscopies necessitates the perfection of a convenient method of anesthesia or analgesia particularly suitable for these procedures. Intravenous thiopental (Pentothal) in combination with one of the muscle-relaxing agents is one of the best methods available. However, this combination necessitates the services of an experienced anesthetist and requires hospitalization of the patient. On the other hand, the usual local anesthesia alone, although sufficiently analgetic locally, frequently renders the examination very inconvenient for the patient. It is on account of these difficulties that physicians often hesitate to refer their patients for endoscopy as a routine procedure, especially in the case of non-hospitalized patients. Ideally, the successful performance of endoscopies requires a general analgetic drug whose effect is of short duration, producing adequate muscle relaxation which at the same time leaves the patient sufficiently awake in order to cooperate, and which also has a wide margin of safety