Abnormal Red Blood Cell Count Spells Trouble in Surgery

ByABC News
March 24, 2008, 12:14 AM

Mar. 23 -- TUESDAY, June 12 (HealthDay News) -- Older men who have too few or too many red blood cells have a higher risk of dying after surgery than those who have the right amount, suggests new research.

The study found that the optimal hematocrit (a measure of red blood cells) for men over 65 was between 39 percent and 53.9 percent, and for every point above or below that normal range, a person's risk of dying within 30 days of non-heart-related surgery increased by 1.6 percent. That means someone with a preoperative hematocrit of 30 had a 14.4 percent higher risk of death than someone with a normal hematocrit level.

"When an elderly man undergoes non-cardiac surgery with a higher than normal or lower than normal red blood cell count, that poses a higher risk of postoperative cardiac events and death," said study author Dr. Wen-Chih Wu, a staff cardiologist and researcher at the Providence Veterans Affairs Medical Center, and an assistant professor of medicine at the Warren Alpert Medical School at Brown University in Providence, R.I.

Wu doesn't believe these findings can be applied to other populations, such as women or younger people. He said that's because older men often have a higher risk of heart disease and may be unaware when they go into surgery that they have underlying heart disease. To compensate for low levels of red blood cells -- which carry oxygen throughout the body -- the heart has to work harder, said Wu. Older people are also more at risk of having other underlying diseases, such as kidney disease, gastrointestinal bleeding or cancer, all of which can affect red blood cell levels.

The current study, which appears in the June 13 issue of the Journal of the American Medical Association, examined data from 310,311 veterans over the age of 65 who had non-cardiac surgeries. The study participants were nearly all male, and most were in their 70s. Forty-three percent had a hematocrit of less than 39 percent prior to surgery, while 0.2 percent had polycythemia, or a high hematocrit, before surgery.