No release of cardiac troponin I during major orthopedic surgery after acute normovolemic hemodilution.
BACKGROUND
Normovolemic hemodilution is a well-accepted method for intraoperative blood salvage. However, some controversy exists concerning the possible risk of myocardial fiber injury as consequence of the reduced oxygen content. Laboratory diagnosis of perioperative myocardial fiber injury is difficult, since biochemical markers are elevated postoperatively due to the surgical trauma. Cardiac troponin I (cTnI) is a new, highly sensitive and specific marker for the detection of myocardial injury. The aim of our study was to investigate whether normovolemic hemodilution in patients with major orthopedic surgery (13 hemodiluted patients, 15 control) induces a release of cTnI.


METHODS
cTnI as a highly specific and sensitive cardiac parameter, as well as total creatine kinase (CK), creatine kinase isoenzyme MB mass (CKMB mass) and myoglobin were measured after induction of anesthesia, after normovolemic hemodilution, prior to retransfusion of blood components, 3 h after surgery, and on the first and third postoperative days.


RESULTS
Prior to retransfusion of blood components the hematocrit was decreased to 25.4 +/- 1.2% (mean +/- SEM; range: 18%-34%) in the control group and to 20.2 +/- 0.8% (mean +/- SEM; range: 17%-24%) in the hemodilution group. Total CK, CKMB mass as well as myoglobin concentration increased significantly in both groups, reaching their maxima within the first day of surgery. In contrast, cTnI was below the detection limit of assay (< 0.5 micrograms/L) at any time.


CONCLUSIONS
We suggest that pre- and intraoperative hemodilution to a hematocrit of approximately 20% by maintaining normovolemia does not induce myocardial fiber injury in patients without preexisting cardiac diseases.
Hobisch-Hagen
P
P
Clinic for Anesthesia and General Intensive Care Medicine, University of Innsbruck, Austria.
Schobersberger
W
W
Falkensammer
J
J
Luz
G
G
Innerhofer
P
P
Frischhut
B
B
Puschendorf
B
B
Mair
J
J
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001804:Blood Transfusion, Autologous; D001810:Blood Volume; D003402:Creatine Kinase / Q000097:blood; D005500:Follow-Up Studies; D006400:Hematocrit; D006438:Hemodilution / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D007430:Intraoperative Care; D007431:Intraoperative Complications; D007527:Isoenzymes; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D017202:Myocardial Ischemia / Q000209:etiology; D009206:Myocardium / Q000378:metabolism*; D009211:Myoglobin / Q000097:blood; D019637:Orthopedic Procedures; D012307:Risk Factors; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
D015415:Biomarkers; D007527:Isoenzymes; D009211:Myoglobin; D019210:Troponin I; D003402:Creatine Kinase