Outcome of surgery on the elderly could be affected by red blood cell count

Jun 13 2007

Researchers in the United States have found that older patients about to undergo major surgery, who have either a high or low red blood cell count, are more at risk for heart attacks or even death following the operation.

According to the researchers their study is the first to demonstrate that even mildly abnormal levels of red blood cells could be detrimental to elderly men undergoing major surgery.

Lead author Dr. Wen-Chih Wu of the Providence Veterans Affairs Medical Center and Brown University in Rhode Island, says the study sheds new light on the potential risks from a common problem among the elderly.

Some experts have previously suggested that very high or very low levels of red blood cells could present a risk prior to surgery, so Dr. Wu and his team were eager to examine that premise and determine at what point abnormal blood counts become a risk factor.

The majority of patients facing surgery will receive a routine blood screening called a hematocrit; a reading with too low red blood cells suggests anemia, while one that is too high suggests the presence of a condition called polycythemia, but until now it has been unclear whether slightly abnormal readings pose any risk.

For the study the researchers examined 310,311 military veterans, mostly men, aged 65 or older who underwent major non-cardiac surgery between 1997 and 2004, whose blood was screened before surgery.

The researchers then checked on how the patients were 30 days after surgery.

They found there was a 1.6 percent increase in the risk of death for every percentage point of deviation from the normal range for red blood cells.

Dr. Wu says they now know there is a risk and when that risk starts to creep up, but it remains unclear what to do about it.

Dr. Wu says if abnormal levels of red blood cell counts are evident before surgery the underlying source needs to be investigated as sometimes they may be correctable.

Experts however advise against rushing to treat patients, especially anemia patients, without more study, as some widely used anemia drugs are known to carry a higher risk of death and blood clots.

The study was funded by the U.S. Department of Veterans Affairs and is published in the current issue of the Journal of the American Medical Association.