Acute isovolemic anemia impairs central processing as determined by P300 latency

Department of Laboratory Medicine, University of California, San Francisco, San Francisco, California, United States
Clinical Neurophysiology (Impact Factor: 3.1). 05/2005; 116(5):1028-32. DOI: 10.1016/j.clinph.2004.12.009
Source: PubMed


Acute anemia slows the responses to clinical tests of cognitive function. We tested the hypothesis that these slowed responses during acute severe isovolemic anemia in healthy unmedicated humans result from impaired central processing.
A blinded operator measured the latency of the P300 peak in nine healthy volunteers at each volunteer's baseline hemoglobin concentration (Hb), and again after isovolemic hemodilution to Hb 5 g/dL. At both Hb concentrations, the P300 latency was measured twice: with the blinded subject breathing air or 100% oxygen, administered in random order.
Anemia increased P300 latency significantly from baseline values (P < 0.05). Breathing oxygen during induced anemia resulted in a P300 latency not different from that at baseline when breathing air (P = 0.5) or oxygen (P = 0.8).
Impaired central processing is, at least in part, responsible for the slowed responses and deficits of cognitive function that occur during acute isovolemic anemia at Hb 5-6 g/dL.
The P300 latency appears to be a potential measure of inadequate central oxygenation. In healthy young adults with acute anemia, erythrocytes should be transfused to produce Hb>5-6 g/dL. As a temporizing measure, administration of oxygen can reverse the cognitive deficits and impaired central processing associated with acute anemia.

Download full-text


Available from: Harriet Hopf, Mar 08, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objectives Understand the timing, extent, and the immediate goals for the initial fluid resuscitation in trauma victims, individualized to specific patients. Review the factors influencing choice of fluid for the initial and ongoing resuscitation. Discuss factors influencing the decision for initiating transfusion therapy, choice of blood products, immediate and delayed risks and benefits of transfusion therapy. Become familiar with the current state of therapies intended for the most severely injured patients, including recombinant factor VIIa and massive blood transfusion protocols. Initial evaluation of an acutely volume-depleted trauma patient will include a primary and secondary survey according to Advanced Trauma Life Support® protocol, an estimate of blood volume deficit (Table 6.1), rate of the ongoing blood loss, and an evaluation of cardiopulmonary reserve and coexisting hepatic or renal dysfunction [1]. The overriding priority of trauma management is to maintain or restore vital organ perfusion and oxygenation above critical levels at an early stage, and to restore perfusion and oxygenation to normal levels as soon as it becomes appropriate. This is best achieved by stopping the bleeding and repleting intravascular volume. Perfusion pressure and oxygenated blood flow to vital organs are important determinants of outcome. Management priorities in an acutely bleeding trauma patient include ventilation and oxygenation (see Chapter 2), assessment of perfusion, estimation of volume replacement requirements, establishment or verification of adequate intravenous (IV) access (see Chapter 4), measurement of blood pressure, placement of electrocardiogram (ECG), pulse oximeter and capnograph, and laboratory studies.
    Preview · Article · Jan 2008
  • [Show abstract] [Hide abstract]
    ABSTRACT: L’anémie est une complication fréquente chez les patients cérébrolésés. Elle est souvent considérée comme un facteur aggravant le développement de lésions cérébrales secondaires. Néanmoins, le niveau optimal d’hémoglobine à maintenir dans ce contexte est actuellement inconnu, et les effets des transfusions de globules rouges chez les patients atteints de traumatisme crânien grave, d’hémorragie sousarachnoïdienne ou d’accident vasculaire cérébral sont discutés: ils peuvent améliorer le transport local d’oxygène mais aussi être grevés de différentes complications. Le but de cette revue est de décrire les connaissances actuelles dans le domaine de l’anémie et des transfusions chez le patient cérébrolésé.
    No preview · Article · Nov 2013 · Réanimation
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Erythrocytes are transfused to treat or prevent imminent inadequate tissue oxygenation. 2,3-diphosphoglycerate concentration decreases and oxygen affinity of hemoglobin increases (P50 decreases) with blood storage, leading some to propose that erythrocytes stored for 14 or more days do not release sufficient oxygen to make their transfusion efficacious. The authors tested the hypothesis that erythrocytes stored for 3 weeks are as effective in supplying oxygen to human tissues as are erythrocytes stored for less than 5 h. Nine healthy volunteers donated 2 units of blood more than 3 weeks before they were tested with a standard, computerized neuropsychological test (digit-symbol substitution test [DSST]) on 2 days, 1 week apart, before and after acute isovolemic reduction of their hemoglobin concentration to 7.4 and 5.5 g/dl. Volunteers randomly received autologous erythrocytes stored for either less than 5 h ("fresh") or 3 weeks ("stored") to return their hemoglobin concentration to 7.5 g/dl (double blinded). Erythrocytes of the alternate storage duration were transfused on the second experimental day. The DSST was repeated after transfusion. Acute anemia slowed DSST performance equivalently in both groups. Transfusion of stored erythrocytes with decreased P50 reversed the altered DSST (P < 0.001) to a time that did not differ from that at 7.4 g/dl hemoglobin during production of acute anemia (P = 0.88). The erythrocyte transfusion-induced DSST improvement did not differ between groups (P = 0.96). Erythrocytes stored for 3 weeks are as efficacious as are erythrocytes stored for 3.5 h in reversing the neurocognitive deficit of acute anemia. Requiring fresh rather than stored erythrocytes for augmentation of oxygen delivery does not seem warranted.
    Full-text · Article · Jun 2006 · Anesthesiology
Show more