I am not a big fan of ordering daily labs. It's expensive. It's labor intensive. It's uncomfortable. It wakes up the patient leading to reduced satisfaction with their hospital experience. Now we learn that that too many blood draws in the hospital may be harming our patients. We already know that moderate to severe hospital acquired anemia (HAA) during acute myocardial infarction (AMI) is associated with a higher mortality. As a standard rule of thumb, almost all patients admitted to the hospital will experience a 2g/dL drop in their hemoglobin. You don't believe me? Look at your patient's trend line the next time you round on them. I suspect a lot of this drop is from bone marrow suppression due to acute illness and dilution from intravenous hydration.
Now we need to add phlebotomy as a modifiable risk factor for the development of HAA. The journal Archives of Internal Medicine recently published an interesting study titled: Diagnostic Blood Loss From Phlebotomy and Hospital-Acquired Anemia During Acute Myocardial Infarction. What was the conclusion? Diagnostic blood loss from hospital phlebotomy may be independently associated with the development of hospital acquired anemia (HAA), which is known to increase mortality after heart attack. As doctors, we have a responsibility to stop making our patients anemic from blood draws. When we draw too much blood, we risk harming our patients.
If the lab isn't going to change our management, we shouldn't order the lab. We don't need to follow a WBC count of 20K every day for the sake of watching it trend down. It doesn't matter. The patient's clinical history and physical should do just fine. In this study, over 17,000 acute myocardial patients from 57 hospitals between 2000 and 2008 were studied who weren't anemic on admission. About 20% of these patients developed moderate to severe hospital acquired anemia during their hospital stay (defined as a hemoglobin dropping from normal to <11g/dL). What did they find? For every 50mL of blood drawn, the risk of moderate to severe hospital acquired anemia increased by 18%. That means we are increasing their risk of mortality ever time we draw a BMP to follow a stable potassium or creatinine level. They also noted a significant variation in the blood letting among hospitals which suggests a lack of systems processes and/or a hospital culture that that is harming our patients. I suspect one could even find large variations between hospitalists too.
For the patients that developed hospital acquired anemia during their stay, the mean average blood letting was an accumulated 173.8 ml of blood, or about half a unit of blood. Just over one in ten patients lost an entire unit of blood from diagnostic blood draws. So what do we do about it? How do we reduce mortality in our AMI patients as it relates to hospital acquired anemia? That's easy.
- Pay it forward. Transfuse at will. For every vial you take, give one back. Don't be shy. We have lots of blood at the Medicare National Bank.
- Recommend all our heart attack patients pick up smoking or smoke more during their hospital stay. Initiate exceptions to the hospital smoking ban in the interest of our patient's safety. That will raise their resting hemoglobin and may prevent HAA from setting in.
- Shut down your in-house lab and refer everything to a send out lab. The farther you send it out, the longer it will take to get back and the less lab that will be drawn.
- Set your critical hemoglobin at 11 g/dL. You won't have a single doctor ordering a CBC. Ever.
If you all have any other great ideas on how we can save our patients from dying in the hospital, I'd love to hear your thoughts.