Gastrointestinal Bleeding – Part 2
Regardless of whether a patient passes blood from the mouth or the rectum, the first step that is undertaken is to examine the patient. The heart rate, blood pressure, and temperature should be obtained. Almost all physicians will have blood samples taken as well. These are usually checked for
the hemoglobin and hematocrit, which are indirect measures of how much red blood cell mass is in the patients arteries and veins. The “H and H” however, can be misleading in a rapid bleed as it can take 12 hours for these values to equilibrate.
In addition, most physicians will send a blood sample to the laboratory in preparation of a possible transfusion. They will order either a “type and screen” or a “type and cross”. When the lab takes a blood sample and types it they are checking to see what the major blood group a patient is in. For example, patients can be blood types A, B, AB, or O. The also check the Rh status of the patient which can be either + or -. The “screen” part checks for the presence of other antibodies or proteins in the patient’s blood that might cause a less severe transfusion reaction if mismatched blood was given.
Most laboratories can do a type and screen on a blood sample in about an hour. At the end of the type and screen the blood bank will know the profile of the patient’s blood but will not set aside any units of blood that are in reserve for that particular patient. If it is decided later that a transfusion is needed for a patient with only a type and screen, there will be addtitional time required to actually match up the patients profile to a unit or units of blood.
In a type and cross, the same things are done in a type and screen, but it addition, the blood bank will go through their stored blood and look for units that match the patient’s blood and will actually tag these units as immediately available. In effect, there are units of blood sitting on a refrigerator shelf with a patient’s name on it. If a patient who has a completed type and cross requires a transfusion, the blood is available much more rapidly than if only a type and screen had been done.
It is much more costly to do a type and cross than a type and screen. However, in patients with brisk gastrointestinal bleeds, experienced physicians will go straight to the type and cross and will request units be set up in bunches of 4 or 6 units.
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