LITERATURE REVIEW Frederick W. Campbell, MD, Editor

SCIENTIFIC ARTICLES

Sigel D, Hulley SV, Black DM, et al: Diuretics, serum and intracellular electrolyte levels, and ventric- ular arrhythmias in hypertensive men. J Am Med Assoc 267:1083-1089,1992

In a randomized controlled trial, 233 hypertensive men received hydrochloorthiazide alone, with potassium replacement, with potas- sium and magnesium replacement, with triamterene, or placebo. Twenty-four-hour Holter monitoring, and serum and intracellular (leukocyte) potassium and magnesium levels were recorded. Se- rum potassium levels were 0.4 mmol/L lower in the hydrochloorthi- azide group than in the placebo group. This differente was not affected by supplementation. The prevalente of ventricular arrhyth- mias was not affected by randomized treatment. Blood cel1 magne- sium and potassium levels were not reduced by diuretic therapy or related to arrhythmias. Electrolyte supplements did prevent the occasional occurrence of marked hypokalemia. Al1 12 men who developed hypokalemia I 3.0 mmol/L were among the hydrochlor- thiazide alone group. There was a twofold increase in the preva- lente of arrhythmias when hypokalemia was present. Monitoring potassium values after starting diuretic therapy, rather than em- piric supplementation, is indicated.

Boldt J, Zickmann B, Scholz HS, et al: Heparin management dwing cardiac surgery with respect to various blood-conservation techniques. Surgery 111: 260-265,1992

To determine the influence of blood-conservation strategies on heparin anticoagulation and neutralization during cardiac surgery, patients undergoing coronary bypass surgexy were randomly di- vided into six groups. Blood conservation was achieved by cel1 saver, hemofiltration, acute normovolemic hemodilution, and plas- mapheresis, alone or in combination. Hemodilution and plasma- pheresis were performed after induction of anesthesia but before surgery. After heparinization (300 U/kg), there were no differ- ences in plasma heparin levels or activated clotting time measure- ments in the six patient groups, although anti-thrombin 111 and fibrinogen levels were moderately reduced in the cell-saver group. Clinical heparin neutralization was obtained in al1 groups by administration of protamine sulphate. Heparin rebound did not occur. Postoperative blood loss was greatest in the cell-saver patients. These blood-conservation strategies did not affect heparin- protamine management.

Lavee J, Savion N, Smolinsky A, et al: Platelet protection by aprotinin in cardiopulmonary bypass: Electron microscopic study. Ann Thorac Surg 53:477- 481,1992

Twenty patients undergoing complicated cardiac operations received aprotinin (total dose, 6 to 7 x 106 KIU) or placebo before and during cardiopulmonary bypass. Platelet count and aggrega-

tion on extracellular matrix assessed by scanning electron micros- copy were measured preoperatively, at termination of bypass, and 90 minutes after. At both postbypass periods, al1 10 aprotinin- treated patients revealed normal platelet aggregation unchanged from preoperative levels (grade 3.5 on a scale of 1 to 4). Placebo- treated patients showed markedly abnormal aggregation (grade 1.4). Platelet counts were similar in both groups. Postoperative bleeding and blood requirement were significantly lower in aproti- nin-treated patients.

Wagne JS, Lin CY, Hung WT, et al: Thromboelasto- gram fails to predict postoperative hemorrhage in cardiac patients. Ann Thorac Surg 53:435-439,1992

NO single variable from routine coagulation tests or thromboelas- tography correlated with the amount of postoperative chest tube drainage in 101 patients undergoing cardiac operation. Throm- boelastograms (TEG) and routine tests resulted in a similar incidence of false-negative results in patients who developed excessive hemorrhage, 46% and 52%, respectively. Thirty-seven patients had abnormal preoperative thromboelastograms. Com- mon prebypass abnormalities were clotting factor deficiency and fibrinolysis. Abnormal thromboelastograms in 34 patients after bypass most commonly demonstrated hypercoagulability and fibrin- olysis. Only two of 18 patients with TEG-described fibrinolysis after cardiopulmonary bypass experienced excessive hemorrhage.

Davies GG, Wells DG, Mabee TM, et al: Platelet- leukocyte plasmapheresis attenuates the deleterious effects of cardiopulmonary bypass. Ann Thorac Surg 53:274-277,1992

Plasmapheresis was performed prior to cardiopulmonary bypass in 32 patients undergoing myocardial revascularization. Approxi- mately 25% of circulating platelets and 11% of circulating leuko- cytes were harvested for reinfusion after bypass. Compared to a historica1 control group, platelet and leukopheresis reduced postop- erative chest tube drainage (788 v 425 mL), decreased homologous bloed administration, and improved pulmonary function (postoper- ative Pa02 94 mmHg v 119 mmHg).

Edmonds HL Jr, Griffiths LK, van der Laken J, et al: Quantitative electroencephalographic monitoring during myocardial revascularization predicts postop- erative disorientation and improves outcome. J Tho- rac Cardiovasc Surg 103:555-563,1992

Quantitative EEG monitoring detected episodes of apparently perfusion-related cerebral cortical dysfunction and predicted post- operative disorientation (29% incidence) in 48 patients undergoing myocardial revascularization and hypothermie cardiopulmonary bypass. Electroencephalogram (EEG) monitoring was performed using conventional 19-lead EEG and CIMON Queeg analysis to measure relative low-frequency power. One-half of the intraopera-

Journal of Cardiofhoracic and VascularAnesthesia, Vol 6, NO 5 (October), 1992: pp 633-635 633