R.M. Lindsay

REDUCTION OF THROMBUS FORMATION ON DIALYSER MEMBRANES BY ASPIRIN AND RA 233

Abstract Thrombus formation, despite efficient heparin anticoagulation, takes place on the dialysis membranes of the Gambro-Alwall dialyser, causing a high blood-loss to the patient. This thrombus formation is associated with a fall in the patients platelet-count over the course of dialysis. To test the hypothesis that platelet retention on these membranes is an early step in the reaction leading to thrombus formation, a double-blind trial of anti-platelet agents (aspirin and a pyrimido-pyrimidine compound [RA 233]) was carried out. These agents significantly lowered platelet-adhesiveness, reduced the fall in platelet-count over the duration of dialysis, abolished the significant fall in plasminogen level seen during placebo therapy, and reduced the dialyser blood-loss. The results of the trial support the initial hypothesis and also suggest that these anti-platelet agents may be valuable in preventing thrombotic disease.

A Method for the Measurement of Platelet Adhesiveness by Use of Dialysis Membranes in a Test‐Cell

Summary. As part of a study of the thrombogenic properties of dialysis membranes a test‐cell has been devised in which the retention of platelets in the presence of different membranes can be measured. This provides a test for platelet adhesiveness which in certain aspects is more sensitive and reproducible than a glass bead column technique. The normal range for platelet adhesiveness was found to be 31 ± 9% using whole blood and 19 ± 3% using platelet‐rich plasma. The platelet adhesiveness value was largely independent of the packed red cell volume but was, in part, dependent upon the presence of adenosine diphosphate. The membrane test‐cell system was sensitive enough to demonstrate a constant and significant fall in platelet adhesiveness following salicylate ingestion. It was convenient in use as blood anticoagulated with 3.8% sodium citrate allowed delays of up to 1 hr without influencing the result. Heparin was found to have an inhibitory effect on platelet adhesiveness. The use of twin test‐cells allowed platelet adhesion to two different dialysis membranes to be studied simultaneously. It was found that fewer platelets adhered to Cuprophan PT 150 membranes than to PT 300 membranes suggesting that PT 150 membranes may be less thrombogenic in vivo.

SUCCESSFUL TREATMENT OF THREE CASES OF VERY SEVERE BARBITURATE POISONING

Abstract Summarn Three self-poisoned patients with extremely high serum-barbiturate levels (phenobarbitone 58 mg. per 100 ml., butobarbitone 15 mg. per 100 ml., and cyclobarbitone 14·8 mg. per 100 ml.) were successfully treated by prolonged haemodialysis and forced diuresis (combined, in one case, with peritoneal dialysis) besides standard supportive measures. The blood-levels are the highest ever recorded for these barbiturates. These cases illustrate the principles of management in very severe barbiturate intoxication.

Acute renal failure in the cold-agglutination syndrome.

Abstract Two cases of primary atypical pneumonia with resulting cold-agglutination syndrome are described. The organisms responsible were Myco - plasma pneumoniœ in one patient and an adenovirus in the other. Both developed acute renal failure which was successfully managed by haemodialysis in one case and peritoneal dialysis in the other. The importance of warming to a physiological level transfused blood and the dialysate used for peritoneal dialysis or haemodialysis is emphasised.

CLINICAL SIGNIFICANCE OF RENAL HÆMODYNAMICS IN ACUTE MYOCARDIAL INFARCTION

Abstract Renal blood-flow has been recorded in patients with acute myocardial infarction using a radioisotope technique—it was found to be normal in normotensive myocardial-infarction patients but significantly reduced in hypotensive myocardial-infarction patients. The importance of the reduction in the renal blood-flow was assessed by the measurement of intrinsic renal function. Reduction in renal blood-flow after myocardial infarction was associated with the development of acute reversible intrinsic renal failure. It is suggested that monitoring of renal function and the institution of the appropriate therapy in the early stages of acute reversible intrinsic renal failure should be an integral part of the management of patients with acute myocardial infarction.

A SCORING SYSTEM FOR ASSESSING PATIENTS ON REGULAR DIALYSIS

Abstract A prognostic scoring system for patients on regular dialysis is described. In this system twenty-two clinical or biochemical variables are scored -1, 0, 1, 2, 5, 10, or 20, a high score denoting a bad prognosis. The total score enables a patient to be classed in one of four categories A-D. A second system, taking note of social and economic factors, is under consideration.