Document Detail


Oxygen reverses deficits of cognitive function and memory and increased heart rate induced by acute severe isovolemic anemia.
MedLine Citation:
PMID:  11964594     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Erythrocytes are transfused to improve oxygen delivery and prevent or treat inadequate oxygenation of tissues. Acute isovolemic anemia subtly slows human data processing and degrades memory, increases heart rate, and decreases self-assessed energy level. Erythrocyte transfusion is efficacious in reversing these effects of acute anemia. We tested the hypothesis that increasing arterial oxygen pressure (Pao2) to 350 mmHg or greater would supply sufficient oxygen to be equivalent to augmenting hemoglobin concentration by 2-3 g/dl and thus reverse the effects of acute anemia. METHODS: Thirty-one healthy volunteers, aged 28 +/- 4 yr (mean +/- SD), were tested with verbal memory and standard, computerized neuropsychologic tests before and twice after acute isovolemic reduction of their hemoglobin concentration to 5.7 +/- 0.3 g/dl. Two sets of tests were performed in randomized order at the lower hemoglobin concentration: with the volunteer breathing room air or oxygen. The subject and those administering the tests and recording the results were unaware which gas was administered. As an additional control for duration of the experiment, 10 of these volunteers also completed the same tests on a separate day, without alteration of hemoglobin concentration, at times of the day similar to those on the experimental day. Heart rate, mean arterial blood pressure, and self-assessed sense of energy were recorded at the time of each test. RESULTS: Reaction time for digit-symbol substitution test increased, delayed memory was degraded, mean arterial pressure and energy level decreased, and heart rate increased at a hemoglobin concentration of 5.7 g/dl (all P < 0.05). Increasing Pao2 to 406 +/- 47 mmHg reversed the digit-symbol substitution test result and the delayed memory changes to values not different from those at the baseline hemoglobin concentration of 12.7 +/- 1.0 g/dl, and decreased heart rate (P < 0.05). However, mean arterial pressure and energy level changes were not altered with increased Pao2 during acute anemia. CONCLUSION: The authors confirmed that acute isovolemic anemia subtly slows human reaction time, degrades memory, increases heart rate, and decreases energy level. The findings of this study support the hypothesis that increasing Pao2 to 350 mmHg or greater by breathing oxygen reverses all of these effects of acute anemia except for decreased energy.
Authors:
Richard B Weiskopf; John Feiner; Harriet W Hopf; Maurene K Viele; Jessica J Watson; Joel H Kramer; Rachel Ho; Pearl Toy
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Anesthesiology     Volume:  96     ISSN:  0003-3022     ISO Abbreviation:  Anesthesiology     Publication Date:  2002 Apr 
Date Detail:
Created Date:  2002-04-19     Completed Date:  2002-05-02     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  871-7     Citation Subset:  AIM; IM    
Affiliation:
Department of Anesthesia, University of California, San Francisco, California 94143-0648, USA. weiskopf@anesthesia.ucsf.edu
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MeSH Terms
Descriptor/Qualifier:
Acute Disease
Adult
Anemia / physiopathology,  psychology*
Blood Viscosity
Cognition Disorders / drug therapy*
Female
Heart Rate / drug effects*
Hemoglobins / analysis*
Humans
Male
Memory / drug effects*
Oxygen / blood,  therapeutic use*
Grant Support
ID/Acronym/Agency:
1 P50 HL54476/HL/NHLBI NIH HHS; 5 MO1 RR-00079/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Hemoglobins; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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