Every two seconds, someone in the U.S. requires a blood transfusion—a life-sustaining process where donated blood or blood components are given to individuals experiencing blood loss due to medical conditions, injuries, or surgical procedures.
An expert in transfusion medicine explains the reasons why some patients require blood transfusions and how the process works.
- Blood transfusions are essential for individuals with anemia, cancer, clotting disorders, and those experiencing traumatic injuries.
- The transfusion process typically takes up to four hours for a single unit of blood, with careful monitoring for reactions.
- While generally safe, potential side effects include mild allergic reactions and, rarely, more serious complications like incompatible blood reactions.
- Rigorous testing ensures blood safety, screening for infectious diseases and compatibility with the recipient’s blood type.
- Consistent blood donations are crucial to maintaining an adequate supply and saving lives.
“Some people, like cancer patients receiving chemotherapy, may need regular transfusions over many months, while a patient suffering from a severe traumatic injury, such as a car accident or gunshot wound, may need dozens of units of blood urgently,” says Dr. Elizabeth Stone, assistant attending physician in transfusion medicine and cellular therapy at NewYork-Presbyterian/Columbia University Irving Medical Center. “There’s no substitute for blood, and if we don’t have a constant supply from healthy donors, patients may not get the lifesaving treatments they need.”
What circumstances typically necessitate a blood transfusion for a patient? The most frequent reason is severe anemia—a deficiency of red blood cells hindering oxygen transport throughout the body. However, a wide range of medical conditions can lead to the need for a transfusion.
These include patients undergoing cancer treatment with chemotherapy or immunosuppressants, who may require platelet transfusions to prevent bleeding. Individuals with clotting disorders, or those taking anticoagulants, might need plasma transfusions to restore blood clotting ability before surgery. And, of course, patients experiencing rapid blood loss from trauma or critical illness often require immediate blood replacement to survive.
During a scheduled transfusion, it can take up to four hours to administer a single unit of blood—roughly 12 ounces. Healthcare providers intentionally avoid rapid transfusions, particularly in patients with cardiac or kidney disease, to prevent circulatory overload. The initial 15 minutes involve a slow infusion rate, closely monitored for any adverse reaction. A patient’s vital signs are checked before, at 15 minutes, and periodically throughout the process. Most patients tolerate transfusions well, experiencing no significant discomfort.
In cases of severe trauma with acute blood loss, a unit of blood can be transfused in as little as a minute or two, prioritizing life-saving intervention while carefully monitoring the patient.
The process itself shouldn’t be painful. A small needle is used to access a vein, which may cause initial discomfort. Patients might feel slightly chilled, as red blood cells are stored refrigerated. Any pain or unusual sensations during a transfusion should be immediately reported to the care team.
Common side effects are typically mild allergic reactions, such as hives or itching, easily managed with allergy medication. Some patients may experience a fever due to residual white blood cells in the blood unit, or chills. If a fever develops, the transfusion is halted for further evaluation.
Serious reactions are rare, but can occur if incompatible blood is transfused. Each person has a blood type—A, B, AB, or O—and is either Rh positive or Rh negative. Receiving compatible blood is critical. Furthermore, patients who have received prior transfusions or been pregnant may develop antibodies against red blood cell antigens. In these cases, blood negative for those antigens is used, with additional testing to ensure safety. Type O negative blood is the universal donor, used in emergencies, but thorough compatibility checks are always performed.
An acute hemolytic transfusion reaction, though extremely rare due to these safeguards, can occur if the wrong blood is given and can be fatal if not promptly treated. Delayed reactions can occur weeks after a transfusion, with symptoms like dark urine, jaundice, fever, and back pain.
The risk of transmitting infectious diseases is low, thanks to a two-part screening process. Donors are first screened with questionnaires assessing behavioral risk factors. Then, every blood donation is tested for HIV, Hepatitis B, and Hepatitis C. In New York, seasonal testing also occurs for mosquito- and tick-borne illnesses like West Nile virus and babesiosis.
Maintaining a consistent blood supply relies heavily on donations. Blood cannot currently be manufactured in a lab, and shortages can severely impact patient care. Healthcare professionals and patients alike are grateful for those who donate.
