VIDEO: Hemoglobin Drift after Surgery

Today we will be discussing post-operative hemoglobin drift. In the first few days after a major surgery, downward trends or “drifts” in hemoglobin levels are common but not well understood.

In a recent study published in TRANSFUSION, Dr. Frank and his colleagues retrospectively examined data from 11 common surgeries and over 3100 patients to determine the predictors of hemoglobin drift.

They found that surgeries requiring greater amounts of IV fluid and blood, such as spinal fusions and major pancreatic surgeries had the most post-operative hemoglobin drift.

Dr. Frank reports on the major findings:

“Larger and more invasive surgical procedures had about a 2.5 g/dL downward hemoglobin drift over the first 3 post-operative days, followed by a smaller upward drift of about 0.6 g during the diuresis phase of the post-operative period.”

The smaller, upward drift of hemoglobin can impact transfusion decisions. Dr. Hannon, who wrote an editorial on the subject, points out:

“If a patient is near a bottom on day number two or three but it is known by the care providers that the patient is then going to start an upward drift in hemoglobin that may stop or delay a transfusion.”

In order to provide the best patient care and to transfuse only when necessary, all members of the post-operative care team need to take into account multiple clinical variables including comorbidities, the overall fluid balance, hemodynamic stability, and the predicted hemoglobin drift, not just isolated hemoglobin values.

Although the exact causes of hemoglobin drift are not well understood, Dr. Frank speculates that bleeding after surgery, excess fluid and hemodilution, larger than necessary blood draws for lab tests, reduced erythropoiesis, and a shortened life span of transfused red blood cells may be contributing factors.

We’ll be back with another edition of Transfusion News on June 30th.  Thanks for joining us.


1. Grant MC, Whitman GJ, Savage WJ, Ness PM, Frank SM. Clinical predictors of postoperative hemoglobin drift. Transfusion 2014;54:1460-1468.
2. Hannon T. Do you Catch My Drift? Transfusion 2014;54:1448-1449.


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