Internal Monitoring Tubes
and Hospital Induced Anemia
These tubes are invasive, meaning that doctors have to insert them into certain arteries and large veins to monitor the blood pressure and the dynamics of the blood flow through the heart and lungs. Monitoring blood pressure in the arteries requires that a catheter be placed in one of the arteries of the wrist, arm, or leg. The nurse or doctor attaches this catheter to a fluid-filled bag via a plastic tube and keeps it under high pressure to prevent hemorrhage. The nurses and doctors also use these catheters to obtain blood samples for testing. While on one hand it is good to avoid multiple needle sticks for blood samples, this presents a high risk for hospital induced anemia (or iatrogenic anemia, as health-care professionals sometimes call it) because the nurse or doctor must allow some of the blood to flow out in order to avoid testing a mixture of blood and intravenous fluid.
Hospital induced anemia is a major problem among the critically ill. ICU patients require many blood tests every eight hours. Those with arterial lines have about 20 cc of blood removed every three to four hours for blood gas analysis and arterial line calibration. The result of all this is that hospital personnel are draining too much blood from critically ill people. One would almost think that medieval bloodletting was still in vogue. Hospital induced anemia is a serious problem because the victims are already weak and cannot afford such blood loss. The result of this kind of anemia is having insufficient amounts of oxygen circulating to the vital organs, resulting in damage to the brain, heart, lungs, liver, and kidneys. This condition also slows healing of surgical wounds and worsens problems associated with poor circulation.
The amazingly sad thing about hospital induced anemia is that medical researchers have recognized it in the medical literature for at least the past twenty years. The solution is simply to use smaller test tubes. Laboratory personnel don't need large blood samples - they only use about 10 percent of the blood drawn for testing. The other 90 percent winds up as medical waste. The only way to protect the patient from this situation is to tell the charge nurse that you are aware of the possibility of too much blood being drawn for testing and you would like to monitor the situation. The more that patients and family members remind nurses of the risk of damaging events, the more diligent nurses are likely to become in preventing them. If you or a loved one has an arterial or central venous line from which blood is to be drawn for testing, you might want to tell the nurse that you have been reading about hospital induced anemia and have a couple of questions. Here is what you might ask:
. How much blood do you intend to draw out to flush the line for each test?
. Is it possible to group all the routine blood tests at specific times to reduce the amount of blood loss for flushing the line?
. How much blood will you draw out for test samples?
. Wouldn't the smaller pediatric (child-size) test tubes provide enough of a sample?
. Are you going to monitor the blood test results for any signs of anemia?
Hospital induced anemia was the problem with Maria P., a sixtyeight-year-old who entered the hospital for a gall bladder removal. She went to the surgical ICU after surgery and stayed there for twelve days for control of diabetes, high blood pressure, and congestive heart failure. The day that the doctors transferred Maria to the stepdown unit, she went into respiratory crisis and cardiac arrest. The nurses and physicians responded within seconds, and they stabilized her within three minutes of the arrest. Although her heart and lungs were functioning, they could not awaken her. She had brain damage beyond repair and remained in a coma for eight months before she died.
The family's attorney asked me to investigate why there was so much brain damage after the textbook performance in reviving the patient. This was indeed a fascinating mystery. The answer was in the gradual and unnoticed deterioration in the blood count of red blood cells, hemoglobin, and hematocrit. She had significant blood loss anemia, but there was no record of any active bleeding, and there was no problem maintaining her blood pressure. Finally, having written about hospital induced anemia in my master's thesis back in 1988, I started to calculate the amount of blood lost to the number of blood tests and arterial line calibrations Maria had had. It turned out that the nurses and physicians were unwittingly draining about 250 milliliters of blood from the patient every day for twelve days. In healthy adults, this would not have been significant, but Maria's ailing body was unable to compensate. Thus she became anemic, and her heart, brain, lungs, and other vital organs lacked sufficient oxygen. Taking samples with smaller tubes that are already available on all pediatric floors and units could have prevented this tragedy.