A Simple Rule for Hemoglobin / Hematocrit (Hgb/Hct)

Many patients have a low hemoglobin (Hgb) and Hematocrit (Hct) level.  In most cases these patients will be anemic when they show up for their "Elective" cardiac surgical procedure.  Our goal then becomes focused on finding the cause for the anemia:  is it iron-deficiency, chronic disease, hemodilution, or mechanical loss.

But, how do you evaluate inconsistencies in the Hgb and Hct?  To help evaluate a patient's red blood cell (RBC) panel, remember the rule of three.

The Hct should be three times the Hgb, and the Hgb should be three times the RBC.

RBC X 3 = Hgb X 3 = Hct

    this formula is especially helpful when assessing a patient's low Hct as a result of fluid volume overload.  If the Hct is greater than three times the Hgb, then the patient is dehydrated.  If the Hct is less than three times the Hgb, the patient is hemodiluted.

In order to validate your suspicions, look at the Sodium (Na+) ion and Blood Urea Nitrogen (BUN) values.  The Na+ and BUN will also be elevated if the patient is dehydrated, and low if the patient is hemodiluted.

Heartpumper, Inc. '04