Evidence for Myocardial Defects Under Extreme Acute Normovolemic Hemodilution With Hydroxyethyl Starch and Lactated Ringer's Solution

Abstract

Acute normovolemic hemodilution (ANH) has been proposed to avoid the risks of allogenic transfusion. In reference to its cellular effects, ANH reports in the literature are scarce. Using electron microscopy (EM), we evaluated the effects of ANH on cardiac function and myocardial structure. Twenty-five dogs were prospectively randomized to a control group (n = 5) or to undergo ANH with 6% hydroxyethyl starch (HES; n = 10) or lactated Ringer's solution (LR; n = 10) administered, respectively, at a ratio of 1:1 or 1:3 to the volume of blood removed. Animals were gradually hemodiluted to a hematocrit of 10%, which was accomplished in 80 min. Pulmonary artery catheter and echocardiography were used to evaluate cardiac function. Myocardial samples were taken after the last time point for electron microscopy analysis. Data were obtained during five different stages of ANH, with a mean 20-min interval between each time point. Cardiac index increased significantly in both groups during ANH. A significant decrease in oxygen delivery and oxygen consumption, as well as an increase in oxygen extraction was verified in the LR group. Echocardiography demonstrated a decline in systolic function in the LR group at the end of the experiment. Electron microscopy analysis of the myocardium revealed slight lesions in cardiac cells in the HES group, and moderate-to-significant lesions in the LR group. In this animal species, ANH with HES resulted in better preservation of cardiac function, which was demonstrated by maintenance of systolic function and oxygenation parameters. Minor loss of cellular integrity with HES, in the presence of very low levels of hemoglobin, reinforces these findings.

Blood Tranfusion in Critically Ill Patients: State of the Art

“…Alternative methods of conservation include meticulous hemostasis in surgical patients, 129 erythropoietin administration, 130,131 use of factor VIIa 132 or desmopressin, 133 use of hemodilution, 134 reduction of phlebotomy losses, and reduction of trigger.…”

Impact of Acute Normovolemic Hemodilution in Organ and Cell Structure

“…Such studies, performed with different species and various situations, demonstrated critical hematocrit levels between 10 and 15% (Fraga et al, 2005;Hiebl et al, 2010;van Bommel et al, 2002). In a study performed with dogs submitted to continuous hemodilution with lactated Ringer´s solution, a decrease in heart function (ejection fraction and fractional shortening) was observed when hemoglobin levels reached 3.5 g/dL.…”

“…In a study performed with dogs submitted to continuous hemodilution with lactated Ringer´s solution, a decrease in heart function (ejection fraction and fractional shortening) was observed when hemoglobin levels reached 3.5 g/dL. Also, at this hemoglobin level, oxygen delivery decreased to the point of impairing oxygen consumption (Fraga et al, 2005).…”

“…In an experimental study with dogs submitted to ANH, volume replacement with 6% hydroxyethyl starch 200/0.5 maintained heart contractility at hematocrit levels as low as 10%, while replacement with lactated Ringer's to the same target yielded significant decrease in contractility, with reduction in systolic function, as defined by ejection and shortening fractions. Furthermore, analysis of the myocardial ultrastructure revealed loss in its cellular integrity in the group treated with lactated Ringer´s solution (Fraga et al, 2005).…”

Estudo prospectivo randomizado comparando duas técnicas de expansão volêmica em cirurgia de artroplastia total de quadril: hidroxietilamido (130/0,4) e Ringer lactato

“…Tem sido sugerido que o HES 130/0,4 pode reduzir a resposta inflamatória em pacientes submetidos a cirurgias abdominais de grande porte quando comparado à solução cristalóide (Ringer lactato) (Lang et al, 2003 (Karanko et al, 1987;Boldt, 2000) No nosso meio, a utilização do HES é bastante estudada, do ponto de vista experimental, em técnicas de hemodiluição normovolêmica aguda quanto aos seus efeitos no coração (Fraga et al, 2005), nos pulmões e nos diferentes órgãos . Esses estudos demonstraram que os amidos são superiores aos cristaloides em preservar, durante a hemodiluição, a estrutura celular e orgânica dos órgãos estudados.…”