Effects of acute normovolemic hemodilution on cardiac troponin I and myocardial enzyme / 中华麻醉学杂志

ABSTRACT

ve To investigate the effects of acute normovolemic hemodilution on cardiac troponin I (CTnl) and myocardial enzyme. Methods Twenty-nine ASA I-II patients undergoing hepatectomy or bilateral hip replacement were randomly divided into two groups: hemodilution group (H , n=15) and control group (C, n=14) . The patients were premedicated with diazepam and scopolamine. Left radial artery was cannulated for intra-arterial pressure monitoring and the letting of blood. Right internal jugular vein was cannulated for fluid administration and CVP monitoring. Anesthesia was induced with midazolam 0.15-0.30mg?kg-1 , fentanyl 4?g?kg-1 and vecuronium 0.08-0.1mg?kg-1 and maintained with infusion of midazolam (0.03-0.10 mg?kg-1?h-1), fentanyl (0.15-2.0?g?kg-1?h-1) and vecuronium (0.5-1.0?g?kg-1?min-1). After tracheal intubation the patients were mechanically ventilated with 100% O2 and PETCO2 was maintained at 35-45 mmHg. 15 min after induction of anesthesia hemodilution was started. Blood was withdrawn from radial artery and collected until Hct was reduced to 25%-28% . Ringer's lactate solution and hydroxyethyl starch (HES 6%) were simultaneously infused to maintain blood volume. Blood samples were taken before anesthesia, before blood transfusion, 4h after surgery and on the 1st postoperative day for determination of blood CTnI, CK and CK-MB activities. Results The demographic data including age and body weight were not significantly different between the two groups. Prior to blood transfusion Hct was reduced to 20.33% ?1.91 % in group H and 29.64%?1.78% in group C. CK increased significantly at 4h after operation and on the 1st postoperative day; CK-MB increased significantly on the 1st postoperative day. The difference between the two groups was not significant. CTnI showed little change during and after operation in both groups.Conclusions Our study suggests that hemodilution to 20% Hct does not result in myocardial injury in patients without preexisting cardiopulmonary disease as long as normal blood volume is maintained and patient suffers nohypoxia.