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Biomedical subjects

S R Tosone

Publications and source records attributed to S R Tosone.

7 recordsLinked to original sources
PubMed1998

Hematologic and economic impact of aprotinin in reoperative pediatric cardiac operations.

BACKGROUND: Aprotinin consistently reduces blood loss and transfusion requirements in adults during and after cardiac surgical procedures, but its effectiveness in children is debated. We evaluated the hemostatic and economic effects of aprotinin in children undergoing reoperative cardiac procedures with cardiopulmonary bypass. METHODS: Control, low-dose aprotinin, and high-dose aprotinin groups were established with 15 children per group. Platelet counts, fibrinogen levels, and thromboelastographic values at baseline and after protamine sulfate administration, number of blood product transfusions, and 6-hour and 24-hour chest tube drainage were used to evaluate the effects of aprotinin on postbypass coagulopathies. Time needed for skin closure after protamine administration and lengths of stay in the intensive care unit and the hospital were recorded prospectively to determine the economic impact of aprotinin. RESULTS: Coagulation tests performed after protamine administration rarely demonstrated fibrinolysis but did show significant decreases in platelet and fibrinogen levels and function. The thromboelastographic variables indicated a preservation of platelet function by aprotinin. Decreased blood product transfusions, shortened skin closure times, and shortened durations of intensive care unit and hospital stays were found in the aprotinin groups, most significantly in the high-dose group with a subsequent average reduction of nearly $3,000 in patient charges. CONCLUSIONS: In children undergoing reoperative cardiac surgical procedures, aprotinin is effective in attenuating postbypass coagulopathies, decreasing blood product exposure, improving clinical outcome, and reducing patient charges.

Adolescent↗
PubMed1997

A comparison of the hemodynamic effects of amrinone and sodium nitroprusside in infants after cardiac surgery.

The phosphodiesterase inhibitor amrinone (AMR) increases cardiac output in children after cardiac surgery. In vitro, amrinone has both positive inotropic and vasodilatory effects. However the relative contribution of these effects to the increases in cardiac output observed clinically is unclear, and it has not been demonstrated that amrinone offers a hemodynamic advantage above that of pure vasodilators in infants. We compared the hemodynamic effects of AMR and sodium nitroprusside (SNP) in 10 infants after cardiac surgery. Cardiac index (CI) was measured by thermodilution after SNP administration, titrated to decrease mean blood pressure (MBP) by 20%, and then after a 1.5-mg/kg bolus dose of AMR. Each patient served as his or her own control. Preload, as measured by left atrial pressure and transesophageal echocardiography (in eight patients), was kept constant throughout the protocol. Both SNP and AMR caused significant decreases in MBP and systemic vascular resistance index (SVRI). However, only AMR resulted in a significant increase in CI. The ratio of fractional increase in CI to fractional absolute decrease in MBP was significantly greater for AMR than SNP, indicating greater efficacy for AMR in the treatment of low cardiac output syndrome and suggesting that, in infants after cardiac surgery, AMR has clinically relevant positive inotropic effects.

Amrinone↗
PubMed1997

Functional maturity of the coagulation system in children: an evaluation using thrombelastography.

There are quantitative deficiencies in the coagulation system for at least the first 6 mo of life. Clinical experience, however, does not indicate an increased risk of excessive bleeding during surgical procedures. Thrombelastography, a test providing a functional evaluation of coagulation, was used to assess the hemostatic system of pediatric patients under 2 yr of age. Thrombelastographic data were obtained from 237 healthy pediatric patients less than 2 yr of age undergoing elective noncardiac surgery. Five groups were distinguished: under 30 days, 1-3 mo, 3-6 mo, 6-12 mo, and 12-24 mo. Thrombelastography revealed no defects in coagulation when these groups were compared to each other or to adults, indicating a functionally intact hemostatic process even in neonates. Indeed, children less than 12 mo of age were found to initiate and develop clot faster than adults, with the coagulation process slowing to adult rates after 1 yr of age. In addition to defining functional integrity, our data represents a set of pediatric control thrombelastographic values that have not been previously reported and that may become important in understanding coagulation changes that accompany disease states and surgery in pediatric patients.

Age Factors↗
PubMed1997

Predicting and treating coagulopathies after cardiopulmonary bypass in children.

UNLABELLED: Coagulopathies in children after cardiopulmonary bypass (CPB) are complex. There are very limited data correlating coagulation tests with postoperative bleeding. We evaluated coagulation changes after CPB and after the administration of coagulation products to 75 children. Baseline coagulation tests were obtained and repeated after protamine administration, after transfusion of individual coagulation products, and on arrival in the intensive care unit (ICU). Regression analysis demonstrated no baseline coagulation test to predict postoperative chest tube drainage. Weight and duration of CPB were determined to be the only predictors of bleeding. Further analyses demonstrated that children <8 kg had more bleeding and required more coagulation products than children >8 kg. Postprotamine platelet count and fibrinogen level correlated independently with 24-h chest tube drainage in children <8 kg, whereas postprotamine platelet count and thrombelastographic values did so in patients weighing >8 kg. Platelet administration alone was found to restore effective hemostasis in many patients. With ongoing bleeding, cryoprecipitate improved coagulation parameters and limited blood loss. Fresh-frozen plasma administration after platelets worsened coagulation parameters and was associated with greater chest tube drainage and more coagulation product transfusions in the ICU. Objective data to guide post-CPB component therapy transfusion in children are suggested. IMPLICATIONS: Children <8 kg can be expected to have more severe coagulopathies, require more coagulation product transfusions, and bleed more after cardiopulmonary bypass. Correlations between coagulation tests and postoperative chest tube drainage are defined. Platelets and, if necessary, cryoprecipitate optimally restore hemostasis. Fresh-frozen plasma offers no benefits in correcting postcardiopulmonary bypass coagulopathies in children.

Anticoagulants↗
PubMed1983

Hemodynamic responses to nifedipine in dogs anesthetized with halothane.

The interaction of nifedipine and halothane was examined in 19 dogs. Nifedipine (10 micrograms/kg) was infused over 2 min in animals anesthetized with either 1% or 2% halothane. The predominant hemodynamic effect of nifedipine was a short-lived reduction (less than 15 min) in mean blood pressure accompanied by a decrease in systemic vascular resistance. During 2% halothane anesthesia hypotension mean blood pressure was greater (P less than 0.05) 15 and 30 min after nifedipine than during 1% halothane. Nifedipine hypotension was initially (2 min) associated with a 23% increase in heart rate and a 22% increase in cardiac output in animals anesthetized with 1% halothane, but during 2% halothane there was no change in heart rate. Changes in dP/dt and contractile force were minimal after nifedipine in both groups. The clinical implications of this study are that nifedipine given during halothane anesthesia may be associated with significant hypotension and that higher concentrations of halothane attenuate the reflex compensatory increase in heart rate. Doses of halothane and nifedipine must be chosen cautiously when the drugs are used together.

Anesthesia, Inhalation↗