J. Koscielny E Jung H. Kiesewetter A. HaaB (Eds .)

Hemodilution With 91 illustrations and 79 tables

With contributions by

B. Angelkort, R. Bach, G. Berg, B. Bertram, L. Bette, A. Birk, J. Blume, H. Băhme, I. Bulik, I. Decker, J. Dyckmans, S. Erlenwein, H. Fărster, M. Gerhards, A. HaaB, G. Hamann, L. Heilmann, T. Holbach, R. Hubertus, F. Jung, U. Kăsser, H. Kiesewetter, W Kolepke, J. Koscielny, G. Leipnitz, C. Mrowietz, M. Reim, H. Schieffer, W Schimetta, J. Schwab, J. Simon, S. Spitzer, M. Stoll, T. Tormann, J. Treib, W Vogel, P. Waldhausen, E. Wenzel, H.-J. Wilhelm and S. Wolf

Springer-Verlag Berlin Heidelberg GmbH

Dr. med. J. Koscielny

Prof. Dr. med., Dr.-Ing. H. Kiesewetter

Priv.-Doz., Dr.-Ing. F. Jung

Abteilung fi.ir Klinische Hamostaseologie und Transfusionsmedizin Universitatskliniken W-6650 Homburg/Saar

Prof. Dr. med. A. HaaB

Universitatsnervenklinik - Neurologie Universitatskliniken W-6650 Homburg/Saar

ISBN 978-3-540-55352-6 ISBN 978-3-662-07748-1 (eBook) DOI 10.1007/978-3-662-07748-1

Library of Congress Cataloging Cataloging-in-Publication Data

Hemodilution 1 J. Koscielny ... [et al.]. Includes bibliographical references and index. ISBN 978-3-540-55352-6 1. Hemodilution. 1. Koscielny, J. (Jiirgen) [DNLM: 1. Blood Circulation- Physiology. 2. Hemodilution. WG 166 H489] RC671.5.H4546 1992 616.1'06-dc20 DNLM/DLC for Library of Congress

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© Springer-Verlag Berlin Heidelberg 1992 Originally published by Springer-Verlag Berlin Heidelberg New York in 1992

The use of general descriptive names, trade marks, etc. in this publication. cvcn if the former are not especially identified, is not to hc takcn as a sign that such names, as understood by the Trade marks and Merchandisc Marks Act. may accordingly be used by anyone.

Produc! Liability: The publisher can give no guarantce for information about drug dosage and application thereof contained in this book. In cvery individual case the respective user must check its accuracy by consulting othcr pharmaceutical litera ture.

27/3145/5 4 3 2 1 O- Printed on acid-free paper

Acknowledgment

We are especially grateful to Fresenius AG, Bad Homburg, for supporting this research. Special tribute must also be extended to Dr. Elder Granger, Chief, Department of Medicine, Landstuhl Army Regional Medical Center, who kindly reviewed the English version of this book.

Contents

Abbreviations Used XV

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIX

1 Iron Metabolism

1.1 1.2

2 2.1

2.1.1 2.1.2

2.1.3

2.1.4

2.1.5

2.1.6

2.1.7

J. KosciELNY and H. KIESEWETTER .................... . Theoretical Principles ............................ . Estimation of Hemodilution Intervals ................ .

Clinical Experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hemodilution in Peripheral Arterial Occlusive Disease H. KIESEWETTER, B. ANGELKORT, J. BLUME, F. JUNG, S. SPITZER, M. GERHARDS, and E. WENZEL ...................... . Patients ...................................... . Dilution in the Case of Decreased Hematocrit Values H. KIESEWETTER, J. BLUME, F. ]UNG, s. SPITZER, M. GERHARDS, and E. WENZEL ................................. . Hydroxyethyl Starch or Dextran H. KIESEWETTER, F. JuNG, J. BLVME, and M. GERHARDS ..... Rheologically Adjusted Therapy H. KIESEWETTER, and F. JuNG ....................... . Bag Plasmapheresis as Useful Addition H. KIESEWETTER, J. BLUME, F. ]UNG, M. GERHARDS, G. LEIPNITZ, S. SPITZER, and E. WENZEL ............... . Dilution in Multimorbid Patients H. KIESEWETTER, J. BLUME, F. JUNG, s. SPITZER, R. BACH, A. BIRK, H. ScHIEFFER, and E. WENZEL ............... . Dilution in Patients with PAOD (Stages II-IV) and Coronary Heart Disease H. BăHME and I. BuuK ........................... .

2.1.8 General Conclusions

1 1 3

7

7 7

8

10

13

16

19

21

H. KIESEWETTER, B. ANGELKORT, and H. BăHME . . . . . . . . . . . 23

2.2 Hemodilution in Patients with Ischemie Heart Disease

2.2.1 2.2.2 2.2.3

R. BACH, s. ERLENWEIN, w. VOGEL, J. DYCKMANS, G. BERG, H. ScHIEFFER, and L. BETTE ........................ . Patients ...................................... . Isovolemic Single Dilution ......................... . Conclusions ................................... .

2.3.1 Hemodilution in Ischemie Cerebral Infarction from a Neurologic Point of View

24 25 25 26

A. HAASS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

VIII Contents

2.3 Hemodilution in Ischemie Cerebral Infarction from a Geriatrie Point of View J. ScHWAB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

2.3.2 Hemodilution in Ischemie Cerebral Infarction from an Internalist and Point of View H. KIESEWETIER and B. ANGELKORT . . . . . . . . . . . . . . . . . . . 32

2.4 Hypervolemic Hemodilution in High-Risk Pregnancies L. HEILMANN.................................... 34

2.4.1 Open Study Comparing Colloidal Solutions: Low Molecular Weight Dextran, 10% Haes 20010.5, and Human Albumin 20% . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.4.2 Randomized Prospective Study Comparing Low Molecular Weight Dextran and 10% Haes 200/0.5 in Women with Suspected Placental Insufficiency . . . . . . . . . . . . . . . . . . . . . 35

2.4.3 Double-Blind Study with Naftidrofuryl and 10% Haes 200/0.5 in Women with Fetal Growth Retardation . . . . . . . . . . . . . . 36

2.4.4 Prospective Study with 10% Haes 200/0.5 in Women with Fetal Growth Retardation and lsolated Plasma Volume Contraction 37

2.4.5 Comparison of Two 10% Hydroxyethyl Starches 200/0.5 with Regard to Starch Accumulation in the Placenta . . . . . . . . . . 38

2.4.6 Use of 10% Haes 200/0.5 for Perioperative Thrombosis Prophylaxis in Cesarian Section . . . . . . . . . . . . . . . . . . . . . . 40

2.4.7 Summary of Therapeutic Recommendations . . . . . . . . . . . . . 41

2.5 Hemodilution in Venous Circulatory Disturbances of the Retina S. WoLF, R. BERTRAM, and M. REIM . . . . . . . . . . . . . . . . . . . 42

2.5.1 Hemodilution in Acute Arterial Circulatory Disturbances of the Retina S. WoLF and M. REIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

2.6 Hemodilution in ldiopathic Sudden Hearing Loss H.-J. WILHELM and R. HusERTus . . . . . . . . . . . . . . . . . . . . . 46

2.6.1 Results.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

2.6.2 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

2.7 Perioperative Hemodilution J. SIMON, T. ToRMANN, and T. HoLBACH 48

2. 7.1 Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2. 7.2 Hypervolemic Single Dilution . . . . . . . . . . . . . . . . . . . . . . . 49

2. 7.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Contents IX

3 Hemodilution in Cerebral Circulatory Disturbances: lndications, Performance, Additional Drug Treatment, and Alternatives

:u 3.1.1 3.1.2

3.1.3

A. HAAss. M. STOLL, and J. TREm ................... . Classification of Ischemie Strokes ................... . Aetiological Classification of Ischemie Strokes .......... . Classification of Strokes by Clinica! Stage and Duration of Neurologic Deficit .............................. . Pathophysiological Classification of Acute Ischemie Strokes .

53 53 53

55 55

3.2 Hemorheological Risk Factors as a Basis for Hemodilution . . 58 3.2.1 Hematocrit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 3.2.1.1 Clinica! Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 3.2.2 Plasma Viscosity ami Erythrocyte Aggregation . . . . . . . . . . . 62

3.3

3.3.1 3.3.2

3.3.3 3.3.4 3.3.5

3.3.6

3.4 3.4.1 3.4.2 3.4.3 3.4.4

3.4.5

3.4.6 3.4.7

3.4.8 3.4.9

3.5

3.5.1 3.5.2 3.5.3

Pathophysiologic Basis of Circulatory Disturbances in Acute Ischemie Cerebral lnfarction ....................... . Cerebral Autoregulation .......................... . Acute Disturbed Microcirculation as a Further Attempt at Hemodilution .................................. . Ischemie Penumbra .............................. . Pathophysiologic Basis of Hemodilution ............... . Effect of lso- and Hypervolemic Hemodilution on Cardiac Output and Circulation in thc Penumbra .............. . lndications for Hemodilution ....................... .

Hemodilution in Acute Ischemie Cerebral lnfarction ...... . Optimal Hematocrit ............................. . Hemodilution Studics ............................ . Dcscription of Dextran and Hydroxyethyl Starch Solutions .. Metabolism and Elimination of Plasma Substitutes anei the Consequcnces for the In Yivo Effect ................. . Hemorheologic ami Hemostatic Effects of Dextran 40 and Hydroxyethyl Starch Solutions ...................... . Hemodilution and lntracranial Pressure ............... . lnitiation of Therapy ami Acute Treatment of Ischemie Cerebral lnfarctions ............................. . Long-Term Hemodilution Treatment .................. . Additional Drug Trcatment ........................ .

Clinica! Rcsults of a Double-Blind, Placebo-Controlled, Randomized lso- and Hypervolemic Hemodilution Study A. HAAss. 1. DECKER. G. HAMANN, M. STOLL, and U. KĂSSER Patients and Mcthods ............................ . Results ....................................... . Discussion .................................... .

63 63

65 66 67

70 74

76 76 76 83

85

87 95

97 102 102

106 106 106 110

X Contents

3.6 Other Special Therapeutic Methods A. HAAss, M. STOLL, and J. TREm . . . . . . . . . . . . . . . . . . . . 111

3.6.1 Fibrinolysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

3.6.2 Complete Heparinization . . . . . . . . . . . . . . . . . . . . . . . . . . 113 3.6.3 Calcium Antagonists and Other Substances . . . . . . . . . . . . . 114

4 Comparison of lso- and Hypervolemic Hemodilution with Haes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

4.1 Single Dilution in Healthy Individuals J. KosciELNY, H. F6RSTER, W. KoLEPKE, and F. JuNG . . . . . . . . 115

4.1.1 Course of Infusion and Measurement . . . . . . . . . . . . . . . . . . 115 4.1.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

4.2 Multiple Dilution in PAOD II H. KmsEWETTER, J. BLUME, A. BIRK, and F. JuNG . . . . . . . . . 157

4.3 Summary H. KmsEWETTER, J. KosciELNY, and F. JuNG . . . . . . . . . . . . . . 160

4.4 Practicat Comments on Hemodilution J. KoscmLNY and H. KmsEWETTER . . . . . . . . . . . . . . . . . . . . . 164

4.5 Possible Side Effects of a Haes Infusion and Their Treatment H. KmsEWETTER, P. WALDHAUSEN, W. ScHIMETTA, H.-J. WILHELM, and J. KoscmLNY . . . . . . . . . . . . . . . . . . . . . 165

4.6 Hemodilution Şchemes B. ANGELKORT, R. BACH, A. HAASS, L. HEILMANN' H. KIESEWETTER, J. KoscmLNY, M. REIM, H.-J. WILHELM, and S. WoLF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

5 Methods F. JuNG, H. KmsEWETTER, C. MRowmTz, and S. WoLF . . . . . . 185

5.1 Colloidal and Protein Chemistry Parameters . . . . . . . . . . . . . 185 5.2 Hemorheologic and Blood Picture Parameters . . . . . . . . . . . 188 5.3 Metabolic Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

5.4 Measurement of Oxygen Partial Pressure and 0 2 Saturation . 195 5.5 Measurement of Blood Flow and Pressure . . . . . . . . . . . . . . 198 5.6 Laser Doppler Flux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

5.7 Oxygen Transport Capacity . . . . . . . . . . . . . . . . . . . . . . . . . 205

5.8 Capillary Hematocrit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

List of Contributors

Angelkort, B., Prof. Dr. med. Medizinische Klinik Nord im Klinikzentrum Nord der Stădtischen Kliniken Dortmund, Miinster Str. 240, 4600 Dortmund

Bach, R., Dr. med. Medizinische Klinik und Poliklinik, Innere Medizin III, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Berg, G., Dr. med. Medizinische Klinik und Poliklinik, Innere Medizin III, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Bertram, B., Dr. med. Augenklinik der Medizinischen Fakultăt RWTH Aachen, PauwelsstraBe, 5100 Aachen

Bette, L., Prof. Dr. med. (t) Medizinische Klinik und Poliklinik, Innere Medizin III, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Birk, A., Dr. med. Zentrum fiir GefăB- und Kreislauferkrankungen, 5100 Aachen

Blume, J., Dr. med. Gemeinschaftspraxis fiir Angiologie, Katschof 3, 5100 Aachen

Bohme, H., Prof. Dr. med. Institut fiir GefăBerkrankungen, Zentralkrankenhaus Gauting, Unterbrunner Str. 85, 8035 Gauting/Miinchen

Bulik, I., Dr. med. Institut fiir GefăBerkrankungen, Zentralkrankenhaus Gauting, Unterbrunner Str. 85, 8035 Gauting/Miinchen

Decker, I., Dr. med. Universitătsnervenklinik- Neurologie, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Dyckmans, J., Dr. med. Medizinische Klinik und Poliklinik, Innere Medizin III, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

XII List of Contributors

Erlenwein, S., Abteilung fiir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Forster, H., Praf. Dr. med. Zentrum fiir Anaesthesiologie und Wiederbelebung, Klinikum der Johann Wolfgang Goethe-Universităt, 6000 Frankfurt am Main 70

Gerhards, M., Dipl.-Ing. Zentrum fiir GefăB- und Kreislauferkrankungen, 5100 Aachcn

HaaB, A., Praf. Dr. med. Universitătsnervenklinik- Neurologie, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Hamann, G., Dr. med. Universitătsnervenklinik - Neurologie, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Heilmann, L., Praf. Dr. med. Stadtkrankenhaus Rtisselsheim, Abteilung fiir Gynăkologie und Geburtshilfe, August-Bebel-Str. 59, 6090 Ri.isselsheim

Holbach, T., Dr. med. Abteilung fi.ir Chirurgie, St. Elisabeth-Krankenhaus, 6648 Wadern/Saar

Hubertus, R., Abteilung ftir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Jung, F., Priv.-Doz., Dr.-Ing. Abteilung fiir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Kăsser, U., Dr. med. Abteilung ftir Kardiologie, Robert-Bosch-Krankcnhaus, 7000 Stuttgart 50

Kiesewetter, H., Praf. Dr. med., Dr.-Ing. Abteilung fiir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Kolepke, W., Dr. med. Abteilung fiir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Koscielny, J., Dr. med. Abteilung fi.ir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

List of Contributors XIII

Leipnitz, G., Dr. med. Abteilung flir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saar\andes, 6650 Homburg/Saar

Mrowietz, C., Dipl.-Ing. Abteilung fiir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Reim. M., Prof. Dr. med. Augenklinik der Medizinischen Fakultăt RWTH Aachen, PauwelsstraBc, 5100 Aachen

Schieffer, H., Prof. Dr. med. Medizinische Klinik und Poliklinik, Innere Medizin III, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Schimetta. W., Dr. rer. nat. Abteilung flir ,Jnfusionen und klinische Ernăhrung", Laevosan Gesellschaft m. b. H., Estermannstr. 17, A-4020 Linz

Schwab, J .. Dr. med. Abteilung flir Geriartrie, Jakobi Krankenhaus, 4440 Rheine

Simon. J., Dr. med. Fachabteilung flir Anăsthesie, Caritas-Krankenhaus Dillingen, 6638 Dillingen/Saar

Spitzer. S., Dr. med. Medizinische Klinik und Poliklinik, Innere Medizin III, Universitătsk\inik des Saarlandes, 6650 Homburg/Saar

StoiL M .. Dr. med. Universitătsnervenklinik -Neurologie, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Tormann. T., Dr. med. Institut flir Anăsthcsie, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Treib, J., Universitătsncrvcnklinik- Neurologie, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

VogeL W., Dr. med. Medizinische Klinik und Poliklinik, Innere Medizin III, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

XIV List of Contributors

Waldhausen, P., Dr. med. Abteilung fiir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Wenzel, E., Prof. Dr. med. Abteilung fiir Klinische Hămostaseologie und Transfusionsmedizin, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Wilhelm, H.-J., Dr. med. Klinik und Poliklinik fiir Hals-Nasen-Ohren-Kranke, Universitătsklinik des Saarlandes, 6650 Homburg/Saar

Wolf, S., Dr. med. Dr.-Ing. Augenklinik der Medizinischen Fakultăt RWTH Aachen, PauwelsstraBe, 5100 Aachen

Abbreviations Used

a a-amyl ABO ADP Albumin ART ASA ATP AV AVP BF BFcca BFcap BGA BSR c CAO Ca O~ Ca02chcm CaO~phys CAT CBF CBV ccs CHD Cm CMRO~

co CPP CT cvc CVP d dia DBV DrH E ECL EDTA EF F FIBc FC GFR

Bunsen's solubility cocfficient a-amylase activity arterial branch occlusion adenosine diphosphate albumin concentration in serum arm retina time ( time) acetylsalicylic acid adenosine triphosphate atrioventricular arteriovenous passage time mean blood flow mean blood flow in the common carotid artery mean capillary blood flow blood gas analysis blood sedimentation rate concentration central arterial occlusion oxygen content of the whole arterial blood oxygen content of chemically bound circulating oxygen oxygen content of physically dissolved circulating oxygen computer-assisted tomogram cerebral blood flow cerebral blood volume Canadian Cardiovascular Society coronary heart disease mean erythrocyte count per micrometer capillary cerebral mctabolic rate cardiac output cerebral perfusion pressure computed tomography central vein catheter central venous pressure erythrocyte column diarneter diastolic dyc bolus vclocity duration of reactive hyperernia erythrocyte erythrocyte colurnn length ethylcnediarninetetraacetic acid ejection fraction female free iron-binding capacity visual acuity to count fingers glornerular filtration rate

XVI

Hacs Hb Hbcap Het Hctcap HD hyp HR ICB ICP IM Io ISO

Lactate LDF LG M MA VIS MCHC MCV Md MICRO MW MMn MMw 11after

11pg

l1bcforc

NW NYHA OEF p pC02 pH p.i. p02 p02-art p02-IM p02-cap p02-tc p02-tca pOrtcb p02-tcf pOrven PAI PAOD PEG

Abbreviations Used

hydroxyethyl starch hemoglobin concentration hemoglobin concentration in the microvascular system systemic hematocrit hematocrit in the microvascular system (capillary hematocrit) hemodilution hypervolemic heart rate intracranial bleeding intracranial pressure intramuscular p02 (M. tibialis anterior) scatter intensity isovolemic plasma lactate concentration laser Doppler flux visual acuity to perceive gleam of light ma le mobile artery anei vein imaging systems mean corpuscular hemoglobin concentration mean corpuscular volume median microcirculatory disturbance molecular weight mean molecule number mean molecule weight erythrocytc count after hemodilution in the erythrocyte column missing number of erythrocytes in the plasma gap erythrocyte count before hemodilution in the erythrocyte column wcight of the newborn New York Heart Association oxygen extraction rate significance level carbon dioxide partial pressure pH value in blood (arterial) post infusion (after the end of infusion) oxygen partial pressure arterial oxygen partial pressure intramuscular oxygen partial pressure in tibialis anterior m. capillary oxygen partial pressure transcutaneous oxygen partial pressure anterior antebrachial oxygen partial pressure ( transcutaneous) transconjunctival oxygen partial pressure dorsopedal oxygen partial pressure ( transcutaneous) venous oxygen partial prcssure plasminogen activator inhibitor peripheral artcrial occlusive disease pneumoencephalography

PET Pla Plb PM Protein PR PRIND PTT PU PV PW Pyruvatc r RCF RIND RR SD SEM sTA sys SAE SAH SEA SER so~ SPECT SSSG O Te t-PA T TC TIBc TIA UI V

V rest

vWF VE X

Ahbreviations Used XVII

positron cmission tomogram/graphy plasma gap lcngth after hemodilution plasma gap lcngth beforc hemodilution pcrinatal mortality total scrum protein platclct rcactivity index according to Grotemeyer prolongcd rcvcrsiblc ischemie neurological deficit partial thromboplastin timc pcrfusion unit (unit of laser Doppler method) plasma viscosity wccks of prcgnancy pyruvatc conccntration in plasma crythrocytc columnar radius ristocctin cofactor rcvcrsiblc ischemie ncurological deficit blond prcssure (mcasurcd according to Riva Rocci) standard dcviation standord crror of thc mean spontancous thromhocytc aggregation systolic subcortical atcriosclerotic encephalopathy suharachnoid hemorrhage standardizcd crythrocyte aggregation index standardizcd crythrocytc rigidity index oxygcn saturation singlc photon cmission computed tomogram/graphy Scandinavian Strokc Study Group oxygcn transport capacity of arterial blood tissuc plasminogen activator thrombocytc thrombocytc count total iron hinding capacity transitory ischemie attack unbound iron binding capacity (serum iron) mcan capillary crythrocyte velocity mcan maximum capillary erythrocyte velocity after 3 min of ischcmia mcan capillary erythrocytc velocity at rest von Willcbrandt factor ccll volume of an crythrocyte mcan valuc

lntroduction

Hemodilution is a therapy for vascular diseases. In patients suffering from arterial occlusivc diseases. hemodilution is often of clinica! use if the systcmic hematocrit value is 45'Yo or higher.

In addition to its use in cerebral [10, 97, 131,278,348, 351], retina! [209, 210, 397, 3981. otogcnic [3921, and peripheral circulatory disturbances [6, 55, 175, 176, 177. 228. 258, 266, 302, 3881, hemodilution is often employed in gynecology in the case of placental restricted circulation [124], in cardiology in the case of coronary (ischemie) hcart diseasc [178, 234] and reccntly in the case of cardiac insufficiency [226, 3521 with hyperviscosity.

In 1989 cardiovascular diseases were involved in 50% of deaths in the Federal Republic of Gcrmany (342 700), being the most frequent cause of death. Almost 40% of thcsc patients dicd of coronary hcart disease [349]. In recent years empirica! studies have confirmed the connection between classical risk factors and blood tluidity [5, 188, 233]. The Aachen study [188] also found a significant frequency of pathologically increascd rheologic parameters in vascular diseascs with corresponding risk factors [191]. The incidence of arterial occlusion is doublcd even in cases of slightly restricted blood fluidity [191, 197]. For blood flow in lcss perfuscd arcas blood fluidity may even become a limiting factor [190, 195, 322].

lncrcased hematocrit and hemoglobin content of blood have also been identificd as risk factors for vascular diseases in other epidemiologic studies [30, 38. 166. 345]. Trcatmcnt aimed at reducing hematocrit in circulatory distur­bances bas heen practiced sincc antiquity [21]. A reduction in hematocrit is, in fact, identica! with a reduction in oxygen carriers, that is, the oxygen capacity ( oxygen content) of the blood. On the othcr hand. it causes an in crease in blood fluidity and thcreforc dccreases thc apparent blood viscosity. The results of experimental animal and clinica! studies suggest that the reduction in viscosity overcompensates the loss in oxygen capacity, leading to a hematocrit value betwecn 38% and 42% in patients with circulatory disturbances and thereby even increasing thc oxygen transport rate (oxygen transport capacity) [41, 105, 189, 278].