A randomized prospective analysis of alteration of hemostatic function in patients receiving tranexamic acid and hydroxyethyl starch (130/0.4) undergoing off pump coronary artery bypass surgery.

Postoperative hemorrhagic complications is still one of the major problems in cardiac surgeries. It may be caused by surgical issues, coagulopathy caused by the side effects of the intravenous fluids administered to produce plasma volume expansion such as hydroxyl ethyl starch (HES). In order to thwart this hemorrhagic issue, few agents are available. Fibrinolytic inhibitors like tranexamic acid (TA) may be effective modes to promote blood conservation; but the possible complications of thrombosis of coronary artery graft, precludes their generous use in coronary artery bypass graft surgery. The issue is a balance between agents that promote coagulation and those which oppose it. Therefore, in this study we have assessed the effects of concomitant use of HES and TA. Thromboelastogram (TEG) was used to assess the effect of the combination of HES and TA. With ethical committee approval and patient's consent, 100 consecutive patients were recruited for the study. Surgical and anesthetic techniques were standardized. Patients fulfilling our inclusion criteria were randomly allocated into 4 groups of 25 each. The patients in group A received 20 ml/kg of HES (130/0.4), 10 mg/kg of T.A over 30 minutes followed by infusion of 1 mg/kg/hr over the next 12 hrs. The patients in group B received Ringer's lactate + TA at same dose. The patients in the Group C received 20 ml/kg of HES. Group D patients received RL. Fluid therapy was goal directed. Total blood loss was assessed. Reaction time (r), α angle, maximum amplitude (MA) values of TEG were assessed at baseline, 12, 36 hrs. The possible perioperative myocardial infraction (MI) was assessed by electrocardiogram (ECG) and troponin T values at the baseline, postoperative day 1. Duration on ventilator, length of stay (LOS) in the intensive care unit (ICU) were also assessed. The demographical profile was similar among the groups. Use of HES increased blood loss significantly (P < 0.05). Concomitant use of TA reduced blood loss when used along with HES. r value was prolonged at 12 hours in all the groups and α angle was reduced at 12 hours in all the groups, where as MA value was reduced at 12 th hour in the HES group compared to the baseline and increased in TA + HES group. These findings were statistically significant. No significant change in Troponin T values/ ECG, duration of ventilation and LOS ICU was observed. No adverse events was noticed in any of the four groups. HES (130/0.4) used at a dose of 20 ml/kg seems to produce coagulopathy causing increased blood loss perioperatively. Hemodilution produced by fluid therapy seems to produce Coagulopathy as observed by TEG parameters. Concomitant use of TA with HES appears to reverse these changes without causing any adverse effects in patients undergoing OPCAB surgery.

Use of albumin as a risk factor for hospital mortality among burn patients in Brazil: non-concurrent cohort study / Uso de albumina como fator de risco para mortalidade intra-hospitalar em pacientes portadores de queimaduras no Brasil: coorte histórica não concorrente

CONTEXT AND OBJECTIVE: Among burn patients, it is common to use colloidal substances under the justification that it is necessary to correct the oncotic pressure of the plasma, thereby reducing the edema in the burnt area and the hypotension. The aim here was to assess the risk of hospital mortality, comparing the use of albumin and crystalloid solutions for these patients. DESIGN AND SETTING: Non-concurrent historical cohort study at Faculdade de Medicina de Marília; within the Postgraduate program on Internal and Therapeutic Medicine, Universidade Federal de São Paulo; and at the Brazilian Cochrane Center. METHODS: Burn patients hospitalized between 2000 and 2001, with registration in the Hospital Information System, who received albumin, were compared with those who received other types of volume replacement. The primary outcome was the hospital mortality rate. The data were collected from files within the Datasus software. RESULTS: 39,684 patients were included: 24,116 patients with moderate burns and 15,566 patients with major burns. Among the men treated with albumin, the odds ratio for the risk of death was 20.58 (95 percent confidence interval, CI: 11.28-37.54) for moderate burns and 6.24 (CI 5.22-7.45) for major burns. Among the women, this risk was 40.97 for moderate burns (CI 21.71-77.30) and 7.35 for major burns (CI 5.99-9.01). The strength of the association between the use of albumin and the risk of death was maintained for the other characteristics studied, with statistical significance. CONCLUSION: The use of albumin among patients with moderate and major burns was associated with considerably increased mortality.

CONTEXTO E OBJETIVO: Em pacientes queimados é comum o uso de substâncias coloidais sob justificativa de que é necessário corrigir a pressão oncótica do plasma, reduzindo o edema na área queimada e a hipotensão. O objetivo foi avaliar o risco de mortalidade hospitalar, comparando o uso de albumina e soluções cristaloides para esses pacientes. TIPO DE ESTUDO E LOCAL: Estudo coorte histórico não concorrente na Faculdade de Medicina de Marília, no Programa de Pós-Graduação em Medicina Interna e Terapêutica da Universidade Federal de São Paulo e no Centro Cochrane do Brasil. MÉTODOS: Pacientes queimados hospitalizados entre 2000 e 2001, registrados no Sistema de Informações Hospitalares e que receberam albumina foram comparados com aqueles que receberam outros tipos de reposição volêmica. O desfecho primário foi a taxa de mortalidade hospitalar. Os dados foram coletados dos arquivos do programa Datasus. RESULTADOS: Foram incluídos 39.684 pacientes: sendo 24.116 pacientes com queimaduras moderadas e 15.566 pacientes com queimaduras graves. Entre os homens tratados com albumina, o odds ratio para o risco de morte foi 20,58 (intervalo de confiança IC 95 por cento 11,28-37,54) para queimaduras moderadas e 6,24 (IC 5,22-7,45) para queimaduras graves. Entre as mulheres, esse risco foi de 40,97 para queimaduras moderadas (IC 21,71-77,30) e 7,35 para queimaduras graves (IC 5,99-9,01). A força da associação entre o uso de albumina e o risco de morte foi mantida para as outras características estudadas, com significância estatística. CONCLUSÃO: O uso de albumina entre pacientes com queimaduras moderadas e graves foi associado a aumento considerável da mortalidade.

Efeitos cardiovascular e metabólico da reposição volêmica com hidroxietilamido 130/0, 4 em felinos domésticos com hipovolemia induzida / Cardiovascular and metabolic effects of volemic expansion with hydroxyethyl starch 130/0, 4 in domestic cats with induced hypovolemia

O objetivo deste estudo foi comparar os efeitos da expansão volêmica produzida pelo hidroxietilamido 130/0,4 (HES 130/0,4) ou pelo sangue em gatas com hipovolemia induzida. Foram utilizadas 12 gatas adultas, sem raça definida (SRD), com peso médio de 2,85±0,28kg e hígidas. Os animais foram induzidos à anestesia geral com isofluorano a 5V por cento, intubados e conectados a um sistema sem reinalação de gases. Após a instrumentação, os animais foram mantidos sob anestesia com isoflurano em 1,3V por cento e mantidos em ventilação mecânica, ciclada a pressão. Em seguida, foi induzida a hipovolemia por meio da retirada de 30ml kg-1 de sangue da artéria femoral. Após 60 minutos da estabilização do paciente, os tratamentos foram iniciados. No grupo hidroxietilamido (GH, n=06), os animais receberam, como reposição volêmica, o hidroxietilamido 130/0,4 no mesmo volume de sangue retirado e, no grupo sangue (GS, n=06), os animais receberam o próprio sangue retirado, sendo considerado grupo controle. A pressão arterial sistólica, a diastólica e a média e a pressão venosa central aumentaram após a reposição volêmica em ambos os grupos. Observou-se, para o GH, aumento da PaCO2 no T15, no T30 e no T60. Houve redução do pH no T30 e no T45 e de íons Na+ no T90 para GH. A restauração das pressões arteriais com a administração de HES 130/0,4 foi similar ao grupo controle. A reposição volêmica com HES 130/0,4 produz aumento acentuado da PVC; e o uso do HES 130/0,4 em gatas submetidas à hipovolemia não produziu alterações clinicamente significativas no equilíbrio ácido-básico.

The aim of this study was to compare the volemic expansion effects produced by hydroxyethyl starch 130/0.4 (HES 130/0.4) or blood, in female cats with induced hypovolemia. Twelve healthy adult female cats, crossbreed and weighing an average of 2.85±0.28kg were used. They were induced into general anesthesia with isofluorane at 5V percent, intubated and connected to a non-rebreathing system. After instrumentation, the animals were maintained under anesthesia with isofluorane at 1.3V percent and maintained on pressure cycled mechanic ventilation. Afterwards, hypovolemia was induced by withdrawal of 30ml kg-1 of blood from the femoral artery. After 60 minutes of stabilization of the patient, the treatments were initiated. In the hydroxyethyl starch group (GH, n=06) the animals received hydroxyethyl starch 130/0.4 as volemic expansion at the same volume of blood withdrawed, in the blood group (GS, n=06) the animals received their own withdrawed blood, being considered the control group. The systolic, diastolic and mean arterial pressures and central venous pressure increased after volemic expansion in both groups. An increase of PaCO2 at T15, T30 and T60 in GH was observed. In addition, there was reduction of pH at T30 and T45 and Na+ ions at T90 in GH. The arterial pressure restoration with the use of HES 130/0.4 was similar to the control group; the volemic expansion with HES 130/0,4 produces accentuated increase of CVP; the use of HES 130/0,4 in female cats submitted to hypovolemia did not produce clinically significant alterations in acid-base equilibrium.

Safety of acute normovolemic haemodilution with hydroxyethyl starch during intracranial surgery.

The effect of acute normovolemic haemodilution on haemodynamics, serum osmolality and coagulation parameters was studied in 20 patients undergoing intracranial surgical procedures. After induction of anaesthesia, 740+/-153 ml of blood was collected and the same was replaced with an equal volume of 6% hexaethyl starch. Heart rate (HR), blood pressure (BP), central venous pressure (CVP) and end tidal carbon dioxide tension (Et CO2) were monitored for 45 min. Haemoglobin concentration (Hb), haematocrit (Hct), serum osmolality (Osm), bleeding time (BT), prothrombin time (PT) and platelet count were determined before and 45 min after haemodilution. Hb and Hct were significantly lower following haemodilution (13.1+/-1.8 and 10.3+/-1.7 g/dL for Hb and 38.0+/-4.6%. and 30.1+/-4.5% for Hct). There was no significant change in the HR, BP and Et CO2 throughout the study period. CVP increased marginally from 35 to 45 min but was within normal limits. There was no significant change in serum osmolality, bleeding time and prothrombin time following haemodilution. Platelet count decreased following haemodilution but the values were within normal limits. The brain relaxation, as assessed by a semiquantitative scale, was satisfactory in all cases. None of the patients developed intraoperative brain swelling. In conclusion, acute normovolemic haemodilution with hexaethyl starch is tolerated well haemodynamically. It does not cause changes in serum osmolality which can increase brain oedema. It has no adverse effect on intraoperative haemostasis. It is a safe technique to decrease homologous blood transfusion during intracranial surgery.

Substitutos do plasma / Plasma substitutes

A preocupaçao constante com as complicaçoes advindas da transfusao indiscriminada de sangue, notadamente as doenças transmissíveis e também a falta de uma reserva sangüínea razoável para uma reposiçao emergencial, fizeram com que houvesse um grande impulso no sentido de se buscar uma soluçao alternativa para as perdas sangüíneas e plasmáticas. O objetivo do presente estudo é fazer uma revisao sobre as soluçoes em uso com esta finalidade, seus aspectos fisiopatológicos, complicaçoes e restriçoes ao seu emprego.

Title Extracorporeal Circulation Combined with Hypothermia and Hemodilution Technique

A hypothermic, low flow perfusion, using 5% dextrose in water as the priming fluid in the pump-oxygenator, was carried out to observe oxygen consumption, blood pH changes, and CO2 tension during the bypass period. A low oxygen consumption which was approximately one third of the preperfusion value, was observed during the total by-pass period. This is believed to be due to the effect of low flow rates employed, hypothermia and low CO2 tension observed in these animals. The pH of the arterial blood and the partition of the total CO2 remained within a fairly normal range. There was a marked reduction in CO2 tension during the bypass period. Its harmful effect on the oxyhemoglobin dissociation curve and cerebral circulation was discussed. The hemodilution attendant to the use of 5% dextrose in water as the priming fluid is considered insignificant.