Abnormal Red Blood Cells

Many Heart Patients Anemic After Too Many Blood Tests in Hospital

Often, this anemia persists for a month or more after discharge and could spell worse outcomes -- even death -- down the line, according to a study in the Aug. 8 online edition of the Archives of Internal Medicine .

"This is not just a lab abnormality," said study senior author Dr. Mikhail Kosiborod, a cardiologist with St. Luke's Hospital Mid-America Heart & Vascular Institute in Kansas City, Mo. "These patients actually feel worse after they leave the hospital. Mortality is higher, too."

People with anemia have too-low numbers of the red blood cells that carry critical oxygen to different parts of the body.

The researchers had previously found that about half of heart attack patients who are admitted to the hospital with normal red blood cell, or hemoglobin, counts actually leave with new anemia.

But the majority of these patients had no bleeding complications that could account for the condition.

That led Kosiborod and his colleagues to hypothesize that it was due to the amounts of blood drawn for routine diagnostic tests.

"Drawing blood in a hospital is typically a very common occurrence, particularly in the intensive care unit," said Kosiborod, who is also an associate professor of medicine at the University of Missouri in Kansas City.

The study authors looked at electronic medical records for almost 18,000 patients who'd had a heart attack at one of 57 U.S. hospitals.

While all had normal hemoglobin levels when they were admitted, 20 percent developed moderate-to-severe anemia by the time they left the hospital.

The risk of anemia rose 18 percent for each 50 milliliters (mL) drawn.

"That was probably somewhat more than what we initially expected to find," Kosiborod said.

The average patient had 173.8 mL of blood drawn for testing, or about half a unit of whole blood. That was about 100 mL higher than the blood drawn in patients who didn't develop moderate-to-severe anemia, according to the researchers.

There were also differences in the amount of blood drawn from hospital to hospital.

"Because we see such a significant variation, chances are that one of the reasons for the variation is hospital-based processes of care," Kosiborod said. "Some hospitals draw more blood than others."

Fortunately, the authors have identified a couple of seemingly simple fixes to this problem.

One option would be to use smaller pediatric tubes to draw the blood rather than adult-sized tubes.

Medicine Science » Spur Cell Anemia

The inherited disorders associated with significant acanthocytosis are characterized by an association with neuromuscular disorders. These diseases are presented together in this article because of the common hematologic feature of peripheral blood acanthocytosis.

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The lipid bilayer contains nearly equal quantities (molar ratio 0.9-1) of unesterified cholesterol and phospholipids that are asymmetrically distributed between the outer and inner leaflets. Phosphatidylcholine (30% of phospholipids) and sphingomyelin (30%) are found mainly in the outer layer, whereas phosphatidylethanolamine (28%) and phosphatidylserine (14%) reside in the inner layer.

Although the cholesterol contents of the membrane are in equilibrium with the plasma-free cholesterol, the uneven distribution of phospholipids is maintained by both passive and active processes. Most acanthocytic disorders are associated with acquired abnormalities of the outer leaflet of the lipid bilayer. However, some rare conditions have normal lipids and abnormal membrane proteins.

In severe liver disease, free cholesterol in red blood cells equilibrates with abnormal lipoproteins containing a high free cholesterol-to-phospholipid ratio, resulting in the preferential expansion of the outer leaflet and the development of the spur cell shape. A decrease occurs in polyunsaturated versus saturated and monounsaturated fatty acid content in red blood cells of patients with cirrhosis. This abnormality is more pronounced in patients with spur cell anemia, resulting in the alteration of the red blood cell shape and a decrease of their fluidity. An increase in the proteolytic activity of the erythrocyte membrane is also reported in spur cell anemia. The significance and role of this abnormality in changing the shape of the red blood cell shape and in hemolysis are unknown.

The plasma of some of these patients exhibits decreased activity of lecithin cholesterol acyltransferase, resulting in increased free cholesterol in the outer layer of the red blood cell membrane as a direct consequence of its increased concentration in the plasma. After acquiring these abnormalities in the plasma, the red blood cells undergo a remodeling process in the spleen, which gives them the spheroidal shape with longer and more irregular projections.

Red blood cell membranes, structure, function, clinical implications

The Merck/Merial Manual of Pet Health

Soft Matter: Lipid bilayers and red blood cells

Schalm's veterinary hematology

Understanding Nutrition