What does platelets mean?Platelets by Apheresis is a Clinical Center Home Page.
Plateletpheresis is the process of collecting platelets, a component of blood involved in blood clotting.The method of collecting the platelets, which is performed by a device used in blood donation, is referred to as the term specifically.Platelet transfusion can be a life-saving procedure in preventing or treating serious injuries from bleeding and hemorrhage in patients who have disorders with low platelet count.This process can be used to treat disorders with high platelet counts.
People with leukemia, multiple myeloma, AIDS, hypersplenism, ITP, bone marrow transplant, radiation treatment, organ transplant or surgeries are usually given platelet transfusions.If you have thrombotic thrombocytopenic purpura, platelet transfusions should be avoided because they can make your symptoms worse.It should be avoided in people withHIT or DIC.
If a central venous catheter is being placed, or less than 50,000 L if a lumbar puncture is required, platelets should be used.[2]
Not all platelets are collected by automated apheresis.There are several advantages to separating the platelets from the whole blood at the time of collection.The first advantage is that platelets from a single donation are not enough to give to an adult patient.They must be pooled from several donors to create a single transfusion, and this complicates processing and increases the risk of diseases that can be spread in transfused blood, such as human immunodeficiency virus.There is a citation needed.
The chance of a successful transfusion is improved by collecting the platelets from a single donor.Being able to get a full dose from a single donor is more convenient than finding multiple compatible donors.
Plateletpheresis products are easier to test for than other types of blood products.Pooling of whole blood platelets can be done in an open system where the containers are connected in a way that will expose the platelets to air, and the pooled platelets must be transfused promptly so that there is no time to grow.
Expense of equipment used for collection is one of the problems with apheresis.Whole blood platelets can be made from blood donations that are also used for packed red blood cells and plasma components.
Those with leukemia, AIDS, or with aplastic anemia are recipients in this category.If indicated, one thrombapheresis concentrate should be given until the recovery of platelet function.Spontaneous bleeding occurs when platelets 10,000/L."dry" bleeding is the result of petechiae and ecchymoses only.They won't suffer fatal events if they first have "wet" bleeding.In those with no bleeding or only "dry" bleeding, the threshold for transfusion should be between 5,000 and 10,000/L.The threshold of 20,000/L should be used for people with a high risk of bleeding.The threshold for active bleeding is 50,000/L.An unconfirmed, but helpful, way to determine if a patient is making new platelets is to measure "reticulated" platelets.
The recipients of this category include people with drug-related thrombocytopenia.Platelet transfusions are not recommended for this group of patients because the underlying cause is the destruction of platelets and any newly transfused platelets will also be destroyed.When the immune system destroys the platelets, they may be used in emergency bleeding situations.There are more studies that need to be done.
Disorders of platelet function can be congenital or acquired.Most of these disorders are mild and can be treated with desmopressin.Transfusion isn't necessarily required.If there is a more severe disorder such as Glanzmann thrombasthenia, large amount of platelets may be needed.The number of transfusions may be reduced if the patients are given human factor VIIa.
Cardiopulmonary bypass surgery can result in the destruction of a large amount of the patient's platelets.There are controversial indications for transfusion in such patients.General guidelines only recommend giving desmopressin to patients who are bleeding excessively.
Aspirin is the most common of these.clopidogrel and ticlopidine are commonly prescribed for patients with acute coronary syndromes.Bleeding can be serious when surgery is done after the administration of these drugs.Transfusion is not clear-cut and one has to use clinical judgement in these cases.
The amount of platelets infused and the patient's body surface area are related to the platelet count.The values are usually less than expected.
The value of the CCI is closer to 10,000/L.If the CCI is less than 5,000/L, patients are said to have "refractoriness" to platelet transfusion.
Apheresis is the separation of individual blood components.The earliest forms of thrombapheresis involve the separation of the platelets from the whole blood.Since each blood bag contains a relatively small number of platelets, it can take as many as a dozen blood bags to accumulate a single unit.The risks of the transfusion are greatly increased by this.A "platelet concentrate" is a collection of platelets separated from whole blood.
Automatic thrombapheresis allows blood donors to give a portion of their platelets while keeping their red blood cells.No more than three units of platelets can be taken from a donor.As more suitable donors are recruited, the occurrence of triples has been increasing.
The shelf life of platelets is just 5 days.Some centers are experimenting with 7 day platelets, but this requires additional testing and the product is far more effective when fresh.
Many blood donation organizations don't collect red blood cells because it takes a long time for the human body to replenish its loss.Some centers defer further platelet donations until the red blood cells can be replenished.
In most cases, the blood is returned to the donor.A portion of the donor's blood can be collected in a separate blood bag in certain locations.In Australia, platelets and blood could be collected from an 88 kilogram donor.
White blood cells are collected as an unwanted component with the platelets due to their higher relative density.White blood cells from one or several donors will be collected along with the platelets, since it takes up to 3 liters of whole blood to generate a dose of platelets.A man has about 6 liters of blood.Rejection problems can occur if all of the incidentally collected white blood cells are transfused with the platelets.White blood cells can be removed by the process of leuko reduction.
White blood cells were removed from the blood at the time of the transfusion.It takes a trained person about 10 minutes to assemble the equipment, and this is not the safest or most efficient means of filtration because dead white blood cells can break up into smaller fragments that can still cause a dangerous response from the immune system.Simple filters can lead to increased risks of infections and loss of platelets.thrombapheresis machines can remove white blood cells.
A dose of platelets comes with about 210 white blood cells.This can cause serious damage to the patient's health.As little as 5106 white blood cells can be found in a dose of single-donor platelets.
There are two types of apheresis.In North America and Europe, platelet-rich plasma and buffy coat are used.
Many cancer patients are unable to generate enough platelets of their own, so when they are able to donate, they go to them.
The basic principles of automatic platelet apheresis are the same as in the manual procedure, but the whole procedure is performed by a computer-controlled machine.The unwanted components can be returned to the donor safely if the blood is processed in a sterile single-use centrifuge.The apheresis machine can repeat the draw-centrifuge-return cycle to get more platelets.Most platelet donations are done in blood centers, rather than at mobile blood drives, due to the bulk of the machine.
The safety of both donor and recipient is protected by each country's rules.A platelet donor needs to weigh at least 100 lbs and have a platelet count of 150 x109/L.[3]
One unit has a lot of platelets.It takes 2 liters of blood to produce one unit of platelets.It only takes one liter of blood to produce a unit for regular donors with higher platelet counts.Some people who can give whole blood may not be able to donate because their veins are too small.Each donor's veins are evaluated by blood centers.
A donor has about four liters of blood, which accounts for 8% of body weight.Only 50% of a donor's platelets are ever taken in one sitting, and they can only be used for three days.
Depending on the donor's health condition, most newer apheresis machines can separate a maximum donation of platelets in about 60 to 120 minutes.
The donor is taken into the donation room and sits in a chair next to the machine after a short physical examination.The technician inserts a catheter into a vein in the arm after cleaning one or both arms.One arm is used to draw blood and the other to return it.The process takes about one to two hours, during which blood is pulled into the machine, mixed with an anti-coagulant, spun around, and returned to the donor."Double needle" procedures using both arms tend to be shorter since the blood is drawn and returned through different catheters, and with " single needle " procedures a set volume is pulled and processed in the first part of the cycle.The donor's blood is drawn and returned.
Blood pressure changes, problems with vein access, and the effects of the anticoagulant on the donor's calcium level are three types of side effects that come from the donation of platelets.The effects of blood pressure changes can be nausea, fatigue, and dizziness.Venous access problems can cause a bruise.A supply of calcium antacid tablets is kept close by while donating.During the donation process, donor's levels of calcium and active calcium ion drop because the anticoagulant works by binding to the calcium in the blood.Since calcium enables the function of the nervous system, nerve-ending-dense areas (such as the lips) are susceptible, at least during the donation process.Unusually low calcium can cause more serious problems such as nerve irritation and tetany.Acute hypocalcaemia is usually caused by low calcium levels prior to donation.Increasing calcium intake in the days leading up to donation can help reduce hypocalcaemia.Apheresis donors are usually not allowed to sleep during the long donation process so that they can be monitored.There is a citation needed.
The donor must not take aspirin or other anti-platelet medications for at least 36 to 72 hours prior to donating.Guidelines vary by center.platelets can be prevented from adhering to clot bleeding by taking aspirin.The taking of any NSAID for 36 hours prior is forbidden by some blood centers.