Check Hb post-transfusion?

[talaxandra]

We're having a little dissent at work tonight about how long to wait after a transfusion before taking a repeat FBE. At present the different positions are:

- at least half an hour

- an hour

- four hours

We'll be taking AM bloods regardless, but have a slip for an overnight FBE, too. Opinions?

[Penelope_Pitstop, BSN, RN]

Just adding to the discussion of PRBC's transfusions......how many of you give lasix between units if giving more than one unit of PRBC's?

It depends on the patient. If you've just received a unit, your lungs are clear, pressure's hanging around 90s and you're slightly tachy...I don't think you need the Lasix before your second unit.

[Flo., BSN, RN]

Our standard is 1 hr post transfusion than again in the AM.

Lasix is not a standard order, we give it based on the pt's condition.

[jennybean14, BSN]

The usual where I worked was 4 hours on med/surg, but the doctor orders it when they want it.

All depends on what's going on.

[nursing6207]

Brings up a debate at my hospital. Lab techs absolutely REFUSE to draw blood for anything while a pt is receiving a blood transfusion. I've had a MD's order for now troponins, or a scheduled troponin while a pt was receiving a transfusion and lab made me get an order that it was ok to draw while pt was receiving transfusion. I was livid with the lab tech that day bc she walked into the pts room (I was in the room) saw the blood and instead of explaining herself she walked out. I had to call the lab to figure out why she did not draw the blood and explain As a nurse we are to follow MD orders and if they cannot be done for whatever reason we need an explanation so we can notify the physician.

[Darknights]

From College of American Pathologists 2008

Q. How long should you wait after a unit of blood has been transfused before drawing a complete blood count, or doing other lab work, to ensure accurate test results?

A. Optimum timing of post-transfusion phlebotomy is critical for ensuring meaningful laboratory testing results, and medical judgment is required in making this determination. Several factors must be considered, including the type and amount of blood product given, purpose of the test (that is, the question it is intended to answer), and clinical setting.

In general, it is best to perform phlebotomy when the patient’s circulatory system is in homeostasis. A patient who is bleeding or undergoing blood product transfusion, or both, is not in a steady state. Whenever possible, samples for laboratory testing should be postponed until bleeding has stopped and transfusion is complete. One obvious exception to this rule, however, would be the setting of massive transfusion, during which monitoring certain laboratory values, such as cell counts and coagulation parameters, is essential to guide ongoing therapy. Variables such as patient blood volume, cardiac output, renal function, and volume of blood products transfused affect how quickly homeostasis is achieved following transfusion.

For the evaluation of post-transfusion increments in hemoglobin, hematocrit, and platelet counts, a practical approach is to draw blood samples within 10 to 60 minutes after completing transfusion, as this time interval is aimed at measuring peak recovery.1 Results determined from blood samples drawn later than 60 minutes post-transfusion are increasingly affected by confounding conditions, such as splenic sequestration, sepsis, and consumption.1,2 If the intent is to determine the extent of such confounding processes on red cell and platelet counts, one should combine a 10-minute post-transfusion sample with sequential samples drawn at one hour and 24 hours post-transfusion.

Alterations in chemistry test results following transfusion are not usually a concern in the low-volume transfusion setting. However, assay results may be affected for varying periods following transfusion of large amounts of blood products, as seen in massive transfusion, red cell, or plasma exchange—particularly if the recipient has impaired hepatic or renal function. Banked storage of red cells results in elevated plasma levels of hemoglobin, potassium, LDH, and iron in the blood unit that may, particularly in the metabolically impaired patient, be reflected in the post-transfusion laboratory values. In addition, citrate anticoagulant present in blood products may result in transient hypocalcemia in the recipient.3 Therefore, following large-volume transfusions or exchanges, waiting 12 to 24 hours before drawing samples for chemistry assays will provide results that are more reflective of the patient’s underlying metabolic state.

References

Choo Y. The HLA system in transfusion medicine. In: McCullough J, ed. Transfusion Medicine. New York, NY: McGraw–Hill Book Co;1998:401.

Legler TJ, Fischer I, Dittman J, et al. Frequency and causes of refractoriness in multiply transfused patients. Ann Hematol. 1997;74:185–189.

Brecher ME, ed. Technical Manual. 15th ed. Bethesda, Md.:AABB;2005;649–650.

[Darknights]

Medical Laboratory Observer 2007

Q How long after the completion of a blood-product transfusion can blood for a complete blood count be drawn?

A The objective in obtaining accurate post-transfusion blood counts is to obtain a sample that is a homogeneous mixture of patient and donor cells. If the patient is receiving blood because of an acute hemorrhage, (i.e., from a trauma or during surgery), homogeneity of the circulating blood will not occur until all hemorrhaging has been stopped. How long this takes depends on a multitude of variables including the condition of the patient's heart, kidneys, and circulatory system; the patient's pre-transfusion blood volume; and the age and volume of the transfused cells.

Nevertheless, physicians who are transfusing patients often want to know the effect of an infusion immediately. Except in trauma cases in which the patient's condition is changing rapidly and must be monitored frequently, cell counts drawn during a transfusion provide little useful information. Once all donor cells have been transfused, however, it is conceivable that accurate cell counts can be obtained immediately after transfusion. In light of the many variables that contribute to donor-cell distribution, waiting an hour after the transfusion may provide more accurate results if time allows. (1) Such determinations should be made by the physician on a case-by-case basis.

Drawing post-transfusion blood for chemistry tests, however, temporarily raises the level of several chemistry analytes for prolonged periods. Because up to 25% of the cells in a donor unit can be hemolyzed during storage, specimens drawn after transfusion can have elevated levels of plasma hemoglobin, potassium, LD, and serum iron. (2,3) Depending on the patient's kidney function and other variables, these levels can remain elevated up to 24 hours.

--Dennis J. Ernst MT(ASCP)

Director

Center for Phlebotomy Education

Coalition for Phlebotomy Personnel Standards

References

1. Becan-McBride K, Eisenbrey A, Haraden L. Venipuncture after transfusion. Adv Med Lab Prof. 1999;17(2):4.

2. Narayanan S. The Preanalytic Phase An Important Component of Laboratory Testing. Am J Clin Pathol. 2000;113:429-452.

3. Myhre B. Iron values after transfusion. Tips on specimen transfusion. Montvale, NJ: Medical Economics;1997.

[Darknights]

Why do you want to take blood to check Haemoglobin post transfusion? Your Red Cross states:

Unless the recipient is bleeding or hemolyzing, and

provided the transfused red cells are compatible,

the post-transfusion hemoglobin can be accurately

predicted from the patient’s estimated blood volume,

baseline red cell volume (=blood volume X venous

hematocrit X 0.91) and transfusion volume.

Hemoglobin alone should not be the stimulus for a decision to transfuse.

From the American Red Cross Transfusion Guidelines:

Red blood cells are indicated for patients with a

symptomatic deficiency of oxygen-carrying capacity or

tissue hypoxia due to an inadequate circulating red cell

mass. They are also indicated for exchange transfusion

(e.g., for hemolytic disease of the newborn) and red cell

exchange (e.g., for acute chest syndrome in sickle cell

disease).

Patients must be evaluated individually to determine

the proper transfusion therapy, taking care to avoid

inappropriate over- or under- transfusion. Transfusion

decisions should be based on clinical assessment and

not on laboratory values alone.

Red blood cells should not be used to treat anemia that

can be corrected with a non-transfusion therapy (e.g.

iron therapy). They also should not be used as a source of

blood volume, or oncotic pressure or to improve wound

healing, or sense of well being.

The function of a RBC transfusion is to augment

oxygen delivery to tissues. Hemoglobin levels during

active bleeding are imprecise measures of tissue

oxygenation. Adequate or inadequate fluid resuscitation

can significantly alter the measured hemoglobin

concentration. In addition, a number of factors must be

considered besides the blood hemoglobin level such

as oxygenation in the lungs, blood flow, hemoglobin-

oxygen affinity and tissue demands for oxygen.

Consequently, the adequacy of oxygen delivery must be

assessed in individual patients, particularly in patients

with limited cardiac reserve or significant atherosclerotic

vascular disease. If available, mixed venous O

2 levels, O2 extraction ratios, or changes in oxygen consumption

may be helpful in assessing tissue oxygenation.

patients (see above). The effects of anemia must be

separated from those of hypovolemia, although both

can impede tissue oxygen delivery. Blood loss of greater

than 30% of blood volume causes significant clinical

symptoms but resuscitation with crystalloid alone is

usually successful in young healthy patients with blood

loss of up to 40% of blood volume (e.g., 2- liter blood

loss in an average adult male). Beyond that level of

acute blood loss after adequate volume resuscitation,

acute normovolemic anemia will exist. However, oxygen

delivery in healthy adults is maintained even with

hemoglobin levels as low as 6-7 g/dL. Thus up to 40%

of the blood volume in a bleeding, otherwise healthy

young adult can be replaced with crystalloid without the

need for red cell transfusion.

In support of a conservative red cell transfusion policy in

critical care is a multicenter, randomized, controlled trial

comparing a transfusion trigger of 7 g/dL with a trigger

of 9 g/dL in normovolemic critically ill patients. Overall

30-day mortality was similar in the two groups and in

the subset of more seriously ill patients. However, in less

acutely ill or younger patients, the restrictive strategy

resulted in lower 30-day mortality.

In support of considering cardiovascular status in the

decision to transfuse red cells is a retrospective study

of transfusion in elderly patients with acute myocardial

infarction which showed lower short-term mortality

when patients were transfused with a hemoglobin as

high as 10 g/dL.

This recent article suggests there is a lot of inappropriate transfusing of RBC's occurring. Also interesting how much can be taken for phlebotomy during an ICU stay. No wonder they need transfusions!

http://www.east.org/tpg/SCCMrbc.pdf

ClinLab Navigator - Transfusion

Each unit increases an adult's (70kg) hemoglobin 1g/dL and hematocrit 3%. Follow up measurement of the recipient's hemoglobin and/or hematocrit can be performed between 15 minutes and 24 hours post-transfusion. The optimal time interval for assessment is 15 minutes. Hemoglobin levels obtained at 24 hours post-transfusion are 10% higher than values obtained after 15 minutes.

One unit can replace a blood loss of 500mLs.

American Red Cross Practice Guidelines for Blood Transfusion

Each unit contains approximately 42.5-80 g of

hemoglobin or 128-240 mL of pure red cells, depending

on the hemoglobin level of the donor, the starting

whole blood collection volume, and the collection

methodology or further processing. When leukoreduced,

RBC units must retain at least 85% of the red cells in the

original component.

Each unit of Red Blood Cells contains approximately 147-

278 mg of iron, most in the form of hemoglobin.

[Darknights]

And if you've read all that.......can anyone remember how much blood loss is required to have malaena (not spelling errors. We spell haem, malaena etc differently down under)?

I have an idea it is about one unit but I'm not confident that it is right.

[Darknights]

Oh, and Frusemide......all elderly heart failure patients have their transfusion over three hours rather than our standard one hour. They have an order for IV Frusemide between units if a clinical review by the administering nurse finds them becoming overloaded.

[Darknights]

Although this is an Aussie publication I don't think our measurements of blood volumes etc are too different to you. I found this interesting because it has quite a few actual examples of transfusion incidents. Amazing how delayed some reactions can be.

http://www.health.qld.gov.au/qhcss/qbmp/documents/faq.pdf

[nerdtonurse?, BSN, RN]

With us, it's 4 hours, unless the patient is unstable (heavy GI bleed, for example). Then we get the blood in as fast as possible, recheck between the units, and keep transfusing. The problem with the 1 hr check is like the literature states, that's your highest possible reading. While some people are very reactive to Lasix, some aren't, and the real fun starts if you've got someone who's on dialysis and anuric....you've got to balance volume replacement with not drowning them. If you want to see what the patient is actually going to retain, it's 4 hours.

[Deb123j]

Oh, and Frusemide......all elderly heart failure patients have their transfusion over three hours rather than our standard one hour. They have an order for IV Frusemide between units if a clinical review by the administering nurse finds them becoming overloaded.

You give your PRBC's in one hour!!! Unless it's an emergency, we run PRBC's for 3-4 hours. Lasix is given depending on the pt and lung sounds. Re-checking Hgb in either 1 or 4 hours, depending on the circumstances.

FYI - usually 1 unit bumps up the Hbg 1 pt.