Anesthetic implications of prolonged QT interval syndromes

The prolonged QT interval syndromes consist of two forms, one congenital and one acquired. The congenital form is probably due to an imbalance in the sympathetic nervous system supply to the heart. It is a preventable cause of sudden death both at an early age and during anesthesia. Recognition of congenital forms of prolonged QT interval and treatment with beta-adrenergic blockers have reduced the mortality. Special care in the perioperative period is necessary to prevent anesthetic-related deaths. The acquired form has many causes. These may be present preoperatively or they may occur intraoperatively. It is important that patients with ALQTS are recognized early and the underlying cause treated.     

Quantitation of apo-, mono-, and diferric transferrin by polyacrylamide gradient gel electrophoresis in patients with disorders of iron metabolism

We have developed a polyacrylamide gradient gel electrophoretic method to quantitate apo-, mono-, and diferric transferrin based upon differences in their molecular size. Purified transferrin saturated to different extents (3% to 98%) with iron showed proportions of the three forms as predicted from an approximately random distribution of iron between the two metal-binding sites. The iron distributions in sera of 14 normal individuals similarly correlated with the predicted values. In contrast, 22 of 43 patients with diseases associated with abnormalities in iron or transferrin metabolism had a disproportionate increase in monoferric transferrin. This abnormality occurred in seven of nine patients who had received bone marrow transplants, seven of 14 with chronic liver disease, and eight of nine menstruating women with probable iron deficiency anemia. Interestingly, 11 patients with malabsorption or chronic renal disease had normal iron distributions. The finding of abnormal distributions of iron on transferrin suggests that gradient gel analysis may be a useful tool for studying the physiologic mechanisms controlling iron utilization.     

Vagotomy and pyloric dilatation in chronic duodenal ulceration.

A total of 101 patients suffering from duodenal ulcer underwent truncal vagotomy (TV) combined with pyloric dilatation (PD). They were followed up over six years, and the results were found to compare favourably with those in patients who underwent alternative surgical measures. Before any revisionary surgery 79 patients were classified as Visick grades I plus II. The incidence of recurrent ulceration was 4%. Side effects were noticeably less common than in patients in whom a drainage procedure had been performed, and overall results were compared with those reported for groups of patients treated by proximal gastric vagotomy. The combination of TV and PD is commended on account of its simplicity, safety, and effectiveness at a time when medical treatment for duodenal ulcer is becoming more specific and increasingly effective.     

THE EFFECT OF THE CALCIUM ION ANTAGONIST 8-(N,N-DIETHYLAMINO)-OCTYL-3,4,5-TRIMETHOXYBENZOATEON MALIGNANT HYPERPYREXIA-SUSCEPTIBLE PORCINE SKELETAL MUSCLE

In malignant hyperpyrexia susceptible (MHS) porcine skeletal muscle, a low concentration (100 mumol/l) of the calcium ion antagonist 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate (TMB-8) inhibited KCl-induced contractures, but potentiated contractures induced by halothane, caffeine and succinylcholine. Higher concentrations of TMB-8 (333 mumol/l to 1 mmol/l) contracted MHS muscle, but had little effect on muscle tension in control preparations. Treatments which inhibit excitation-contraction coupling abolished TMB-8-induced hyper-reactivity in MHS muscle. TMB-8 (50 mumol/l and 1 mmol/l) did not alter 45Ca2+ levels in actively loaded microsomal preparations from MHS swine. These results suggest that in malignant hyperpyrexia the primary abnormality occurs proximal to the release of calcium from the sarcoplasmic reticulum, probably at the level of excitation-contraction coupling.     

Intraocular pressure reduction in chronic simple glaucoma by continuous infusion of dilute pilocarpine solution.

Ten hospital outpatients with bilateral chronic simple glaucoma received a single drop of 2% pilocarpine to one eye and a continuous infusion of 0.1 % pilocarpine at a flow rate of 0.01 ml/min to the other eye (both solutions were at pH 7.2). On another occasion the treatments were reversed. Measurements of intraocular pressure (IOP) and pupil diameter were made at 30 min intervals for 2 hours. The continuous infusion of dilute solution was as effective as the single drop of more concentrated solution in reducing IOP and in constricting the pupil; the drop was somewhat faster in producing its effect.