Clinical Practice Guideline

for

ANEMIA AND BLOOD LOSS

Developed for the

Aerospace Medical Association

by their constituent organization

American Society of Aerospace Medicine Specialists

 

Overview: Anemia is a common problem affecting much of the world’s population, especially in developing countries.  Half of all cases worldwide are due to iron deficiency, particularly in the very young, those with poor nutrition, and women of childbearing age.  For American women ages 20-49, the prevalence is estimated to be as high as 11%.  Other less common etiologies include hemoglobinopathies, abnormal red cell membranes, and disturbed B12 or folate absorption.

 

Blood loss can be caused by internal or external hemorrhage as well as blood donation.  Blood donation is a common practice and is, in fact, promoted to the general and military populations through programs sponsored by the American Red Cross and Armed Services Blood Program.

 

Bone marrow donation is also known as Stem Cell Harvest or Peripheral Blood Stem Cell Harvest.  Civilians and military members may volunteer to donate bone marrow for either matched relatives or donor matches through the National Marrow Donor Program or C.W. Bill Young Department of Defense Marrow Donor Program. 

 

Aeromedical Concerns: Irrespective of the cause, anemia or blood volume loss can reduce tissue oxygenation and compromise organ function manifesting as fatigue, generalized weakness, decreased stamina, lightheadedness, chest pain, and decreased Gz tolerance.  Physical exertion and hypoxia can further compromise function and overwhelm the body’s capacity to compensate for the anemia.  In younger patients, these symptoms may not be recognized until the hemoglobin is less than 7 or 8 g/dL.  More elderly patients may recognize these symptoms at hemoglobin levels of 9 to 11 g/dL while patients with chronic disease or gradual loss of red cell mass may report being asymptomatic at levels down to 5 to 6 g/dL.  These clinical observations are based on patient data usually at low altitudes without extreme occupational exposures or duties.

 

For a patient with any baseline hemoglobin level, the above-noted symptoms will be more pronounced in the setting of acute blood loss, particularly if it is accompanied by loss of intravascular blood volume.  A patient may tolerate up to 20% of acute blood volume loss with no cardiovascular compromise.  In a recent study, it was found that the body replaces blood volume at an average of 36 days following a 550 cc whole blood donation.  One study compared the changes in cardiovascular parameters and symptoms between donors who underwent sham, 1-unit, and 2-unit blood donations.  There were no statistically significant differences between the groups.  Nonetheless, it is still important to ensure that aviators do not exhibit any signs or symptoms of anemia.  As a result, acute blood loss between 200-400ml (including blood donation) requires grounding for at least 72 hours.  When the flyer is clinically stable and otherwise fit for returning to flying duties, there is no reason to draw bloodwork following blood loss less than 400 ml or blood donation.  As long as the flyer is feeling well, there is almost never a need to visit the FSO before resuming aviation duties.

 

Bone marrow (Stem Cell) donation is a more involved process than blood donation.  Marrow may be donated via two methods.  The first method involves actual harvest of stem cells from the donor bone marrow.  In this method, patients are admitted to the hospital and may stay anywhere from 8 to 36 hours.  Marrow is collected from the posterior-superior iliac spines or the sternum.  The most common post-procedure symptoms include pain at the donor site (77%), fatigue (38%), nausea (25%), vomiting requiring intravenous medications (8%), and fever (5%).  In order to accelerate recovery, some patients will choose to have autologous blood transfusions, but the overwhelming majority of patients never need a transfusion of any kind after donating bone marrow.  Most women and some men also take oral iron replacement upon discharge.  Pain resolves, on average, in 5.5 days with a range of 1 to 25 days.  Full recovery of pre-procedure hemoglobin levels was observed at 3 months for males and 1 month for females.  The authors noted that more females took iron supplementation than males in that study.

 

A second technique of bone marrow stem cell collection is peripheral blood stem cell (PBSC) apheresis.  PBSC apheresis is accomplished in an outpatient setting.  With this collection method, the donor is given granulocyte colony-stimulating factors (GCSF) approximately one week before the collection.  Once the donor’s WBC count is sufficiently raised, stem cells are harvested from either an IV placed in the donor’s arms or through a central catheter placed in the chest wall.  The collection, similar in nature to a platelet donation, can usually be completed in 1-2 apheresis settings.  The donor has minimal discomfort with this procedure and the side effects are limited to those of the GCSF administration.  There is no prolonged anemia or recovery.  The donor may have an elevated WBC for a few weeks following the donation. 

 

Aviators who donate bone marrow should be removed from flying status until the following parameters have been met:

 

Oral iron supplements are compatible with flying status after successful ground testing.    No waiver is required following bone marrow donation for military aviators.

 

Medical Work-up: Complete history of the anemia to include all treatments.  Current labs to include complete blood cell count with red blood cell indices, peripheral smear, and reticulocyte count must be performed and annotated.

 

Aeromedical Disposition:

 

Air Force: In the US Air Force, evaluations are recommended for hematocrit values below 40% in men and 35% in women.  The exact nature of the work-up should be guided by a thorough history and physical but typically should include a complete blood cell count with red blood cell indices, peripheral smear, and reticulocyte count.  Results from these may indicate the need for evaluation of iron or B12 stores, hemoglobin electrophoresis, or possibly bone marrow biopsy.

 

Army: Anemia is discussed in three different APLs in the Army: Anemias/Acquired (Including Iron Deficiency Anemia), Anemias/Congenital and Anemia/Acute Blood Loss.  Minimum standards for hematocrit in the Army are 40% for males and 37% for females (USAF standards are 40% and 35% respectively).  The work-up for anemias other than that associated with blood donation focuses on discovering the etiology, whether genetic as with the Thalassemias, or anatomic as with blood loss due to colon disease.

 

Continued use of iron, folate and B12 supplementation or other medications (e.g. thyroid supplements) require waiver.  AR 40-8 Temporary Flying Restrictions due to Exogenous Factors discusses donation of blood products.  Army aircrew may not routinely donate blood or plasma more than two times per year.  Following blood donation (200cc or more), aircrew will be restricted from flying duty for 72 hours.  Following plasma donation, aircrew members will be restricted from flying duty for 24 hours.  Bone marrow donors must be cleared by a flight surgeon or APA for return to flight status.

 

Navy: The standards for aviation are derived from healthy aviators, not from hospital patients.  Hence, flyers’  “abnormal” values are generally still within most hospital norms.  Acceptable values for hematocrit are 40-52% in males and 37-47% in females. If the average of three hematocrits (from three separate blood draws, not from the same sample analyzed three times) falls below the normal range but between 38.0% and 39.9% for males (35.0% - 36.9% for females) a work up is initiated, to include thorough history, focused physical, CBC with RBC indices, iron studies, chemistry panel, liver function panel, and thyroid stimulating hormone (TSH).  If history, physical exam, and all labs are within normal limits, the member is PQ and no waiver is required.

 

Civilian: In civil aviation, an evaluation should ensue in any airman who presents with symptoms of an acute or chronic anemia.  In general, if the cause for the anemia is determined and felt to be not a result of a medically disqualifying illness, an individual is allowed to pilot an aircraft as long as their hemoglobin is equal to or greater than 10 gms%.  Flight personnel should be grounded for a period of 24 hr. after donating blood and they should not be permitted to engage in flight above FL 350 for a period of 72 hours after donating blood.  In general, anemias of infection, blood loss, or of a dietary deficiency need to be given serious consideration for return to aviation duties after completion of appropriate therapy.

 

Waiver Experience:

 

Air Force: Review of the Air Force AIWWTS database in Oct 08 revealed 180 individuals listed as having anemia, 22 (12%) were disqualified.  Of those individuals who were disqualified, 12 (55%) were disqualified for coexisting diagnoses and 2 (9%) were disqualified for incomplete work-ups.  The 7 (31%) patients who actually had a definitive diagnosis of iron deficiency or thalassemia were disqualified for not achieving appropriate hematocrit levels.  The one remaining case was a disqualification secondary to complications from sickle cell crisis.  Waiver criteria include a stable or increasing hematocrit above 32% and a clear etiology (or exclusion of the non-iron deficiency anemias).  Among the specific diagnoses most commonly listed were iron deficiency, thalassemia minor, sickle cell trait, anemia from blood loss (through the genitourinary or gastrointestinal tracts), spherocytosis, history of anemia following medical or surgical treatment, and B12 deficiency.  .

 

Army: The Aviation Epidemiological Data Repository was sampled from fiscal years 2004-2008 looking at the unique number of pilots per year.  There were 14,800 rated personnel processed during this period.  With regard to anemia, there were 3 suspended cases and 20 waiver granted cases.

 

Navy: Review of Navy data from approximately 1986-2011 revealed 1,486 individuals evaluated for waiver with a diagnosis of Anemia.  For 950 of these the most recent waiver recommendation was favorable.  145 of those were Air Traffic Controllers, 361 were Naval Aircrew, 2 were UAV crewmembers, 136 were Naval Aviators, SG1, 3 were SG2, 9 were SG3, 85 were Naval Flight Officers, 29 were Naval Flight Surgeons, 118 were Student Naval Aviators, and 39 were Student Naval Flight Officers.

 

Civilian:  As of Jun 2009, there were a total of 519 aviators listed under the Path Codes 966 and 967 that were issues certificates.  The breakdown was 79 first class, 103 second class and 337 third class certificates.

 

ICD9 Codes for Anemia, Blood Loss, and Marrow Donations

280

Iron Deficiency Anemia

281

Other deficiency anemias

282

Hereditary hemolytic anemias

283

Acquired hemolytic anemias

284

Aplastic anemia & other bone marrow failure syndromes

285

Other and unspecified anemias

 

References:

 

American Red Cross Donation Services.  Available at: http://www.redcross.org/donate/give/.  Accessed on October 31, 2008.

 

Armed Services Blood Program.  Available at: http://www.militaryblood.dod.mil/. Accessed on October 31, 2008.

 

Cecil Medicine. 23rd Edition, Goldman L and Ausiello D, editors. New York, Saunders Elsevier. 2008.

 

Clinical Aviation Medicine. Rayman RB, Hastings JD, Kruyer WB, Levy RA. New York, Castle Connolly Graduate Medical Publishing, LLC. 2000.

 

C.W. Bill Young Department of Defense Marrow Donor Program. Available at: http://www.dodmarrow.org/Pages/about/about_program.htm.  Accessed on October 31, 2008.

 

Gandini A et al.  Unrelated allogenic bone marrow donation: short- and long-term follow-up of 103 consecutive volunteer donors.  Bone Marrow Transplantation. 1998;28:369–374.

 

Iron Deficiency – United States, 1999 – 2000. Morbidity and Mortality Weekly Report. 2002;51(40):897-899.

 

National Marrow Donor Program.  Available at: http://www.marrow.org/.  Accessed on October 31, 2008.

 

Pottgiesser T, Specker W, Umhau M, et al.  Recovery of hemoglobin mass after blood donation. Transfusion. 2008.

 

Smith KJ, James DS, Hunt WC, et al.  A randomized, double-blind comparison of donor tolerance of 400 ml, 200 mL, and sham red cell donation. Transfusion. 1996;36(8):674-680.

 

Williams’ Hematology, 7th Ed., Lichtman MA et al (ed.).  New York, McGraw-Hill, Inc. 2006.

 

 

 

Prepared by Drs. Kevin Bohnsack and Dan Van Syoc

September 17, 2011