The different versions of autologous blood transfusion have rekindled interest in a generally valid ‘minimum acceptable hemoglobin concentration’ of patients around or below 10 g Hb/dl. The adequate Hb concentration capable of covering the oxygen demands of the body depends on several variables measurable at the bedside: oxygen consumption VO2, arterial oxygen tension paO2 body temperature, arterial and mixed venous pH, and cardiac output CO as the most important compensatory variable in anemia. Because of the strain imposed on the myocardium and the coronary circulation, anemia should not raise CO to more than twice the resting value, i.e. < 101/ min. Similarly, the mixed venous pO2, as an indicator of tissue oxygenation. should not fall below 35 mmHg. With these two restrictions, we studied the relationships of the above-mentioned parameters . in a computer-supported model. Under otherwise similar conditions, pvO2 falls with an increase in VO2, a decrease in paO2, a decrease in the temperature, an increase in pH, and a decrease in CO. A resting and slightly acidotic patient without other impediments of his cellular oxygen supply – e.g. the patient on chronic hemodialysis – tolerates a Hb level of 6–7 g/dl with a pvO2 barely exceeding 35 mmHg and a CO approximately 50% above baseline. By contrast, the hypermetabolic and hypoxemic intensive care patient needs Hb levels in the low normal range, i.e. 12–13 g/dl, especially if he is also alkalotic. A generally valid ‘minimum acceptable hemoglobin level’ does not exist; the adequate Hb concentration is an individual characteristic needing careful attention. The patient in greatest need of his hemoglobin as a natural safety margin against an oxygen deficit with its potentially lethal sequelae is the critically ill without access to critical care.

Keywords:
Autotransfusion, Hemoglobin levels, Impact variables, Compensatory mechanisms, Computer program
This content is only available via PDF.
© 1989 S. Karger AG, Basel
1989
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.