Red blood cell physiology in critical illness.
OBJECTIVE
Reduction in red blood cell mass, as well as structural and functional alterations of erythrocytes, occurs in critical illness. This review discusses these changes in red blood cell physiology, emphasizing the pathogenesis of anemia in intensive care unit patients.


METHODS
Studies published in biomedical journals.


CONCLUSIONS
Anemia in intensive care unit patients resembles the anemia of chronic disease, being characterized by diminished erythropoietin production relative to decreased hematocrit, altered iron metabolism, and impaired proliferation and differentiation of erythroid progenitors in the bone marrow. Inflammatory mediators play a major role in the development of insufficient erythropoiesis and altered iron metabolism. Furthermore, a proinflammatory milieu promotes structural and functional alterations of erythrocytes, impairing their deformability and possibly impairing microvascular perfusion. Collectively, these changes in red blood cell physiology can impair oxygen transport to tissues and, thereby, might contribute to the development of multiple organ failure in critical illness.
Scharte
Marion
M
Klinik und Poliklinik für Anästhesiologie und operativ Intensivmedizin, Universitätsklinikum Münster, Muenster, Germany.
Fink
Mitchell P
MP
D000740:Anemia / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D003422:Critical Care / Q000379:methods*; D004912:Erythrocytes / Q000378:metabolism*; D015672:Erythroid Precursor Cells / Q000502:physiology; D004921:Erythropoietin / Q000378:metabolism; D006461:Hemolysis / Q000502:physiology; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D007501:Iron / Q000378:metabolism; D009780:Occult Blood; D018962:Phlebotomy / Q000009:adverse effects
D004921:Erythropoietin; D007501:Iron