Donor Health Screening Donor Suitability Evaluation Phlebotomy Post Donation Care and Adverse Donor Reactions · 8 頁
[[p.1]] 3 The blood transfusion centers should ensure the following: 1. The donor is safe and will not suffer from any adverse reactions as a result of blood donation. 2. Also, the blood transfusion center should ensure that, the donated unit will not cause any adverse consequences for the recipient. DONOR SCREENING In order to provide safety to the donor and also to the recipient with quality blood, donor health screening is very essential. Many organizations use photographic identification of the donors for accurate identification and this can prevent early whole blood donation, i.e. before three months. After registration, the blood donor is provided with explana- tory information about the blood donation process. This covers the screening process, phlebotomy, self-deferral and donor confidentiality. The donor is counseled regarding donor criteria for donor selection. After the information and counseling procedure, the donor answers questionnaire designed to safeguard the donor himself and also the recipient who receives his blood. The donor has to answer the “Yes or No” questions. The donor signs the consent form. He agrees for his unit of blood being tested for transfusion transmitted infections and being informed about the positive results. Donor Health Screening, Donor Suitability Evaluation, Phlebotomy, Post-Donation Care and Adverse Donor Reactions 30 [[p.2]] Donor Health Screening, Donor Suitability Evaluation 31 DONOR HEALTH HISTORY AND DONOR SAFETY The blood donors must be in good health. After the donation process, the volume lost is mostly replaced within a few hours and completely within 48–72 hours. Iron stores and red cells are replaced within 7–8 weeks. Thus, blood donation is limited to once in three months to allow the donor with sufficient time for absorption of dietary iron to prevent himself from develop- ing iron deficiency anaemia. Open-ended questions may be asked to know the overall health of the donor. Specific questions relating to cardiac disease, lung disease, liver disease, blood disease, pregnancy and history of cancer may be asked. Donors with medical history are not permitted to donate. Donors on medication may indicate some medical problem with donor, e.g. a donor on antibiotics signifies infection in a donor or some medication of donor can affect the recipient, e.g. donors on aspirin can have anti-platelet effect. Weight of the donor is important for calculation of blood to be drawn. Standards allow donation of 13% of circulating volume of blood. Thus, a person who weighs 50 kg can donate 450 mL of whole blood and a person who weighs 45 kg can donate 350 mL of blood. Age of the donor must be 18 years or more (some countries like USA and Scotland age of 17 years is acceptable). DONOR HEALTH HISTORY AND RECIPIENT SAFETY The most of the questions asked are relating to protect the recipient from infectious diseases originating from the donor. The blood borne diseases such as: 1. HIV-1 and HIV-2 2. Viral hepatitis B and C 3. Malaria 4. Syphilis 5. Babesiosis 6. Chagas disease 7. West Nile virus (WNV) [[p.3]] 32 Essentials of Blood Banking and Transfusion Medicine Some of these are permanently deferred and some temporarily deferred for prescribed period of time after treatment. Note: Refer to topic on TTDs. DONOR PHYSICAL EXAMINATION Donor physical examination is to evaluate donor’s vital signs which are checked before donation. 1. Pulse rate and rhythm 2. Blood pressure 3. Temperature 4. Venipuncture sites Individuals with a fever, high blood pressure (generally higher than 180/100 mm of Hg), very high or very low heart rate or an irregular heart beat are not permitted to donate blood. The donor’s pulse of 60 to 100/min. is acceptable. Athletic donors with pulse of 50/minute is acceptable. The donor’s blood pressure of systolic 100–140 mm of Hg and diastolic of 60 to 90 mm of Hg is arbitrarily acceptable. Donor’s temperature of more than normal is not acceptable. Elevated temperature signifies potential source of infectious agent to a recipient. Inspect the arm for infections, scars and venipuncture site for any signs of drug abuse. To make sure that blood is not drawn from anaemic donor, the haemoglobin of the donor has to be 12.5 gm% or more and haematocrit has to be 38%. CONFIDENTIAL UNIT EXCLUSION (CUE) Some of the donors donate under pressure of their peers, friends or relatives. In such occasions, in some countries an opportunity is given to the donors to exclude units confidentially. A confidential unit exclusion form is given to the donors and such units are not used for transfusion and are discarded. Some countries do not follow this CUE. [[p.4]] Donor Health Screening, Donor Suitability Evaluation 33 Steps for Donor Suitability Evaluation The steps of donor suitability evaluation are as follows. PHLEBOTOMY The phlebotomist has to follow the following guidelines of WHO best practices in phlebotomy3 for drawing blood: Step 1. Identify donor and label blood collection bag and test tubes • Ask the donor to state his/her full name. • Ensure that: The blood collection bag is of the correct type; The labels on the blood collection bag and all its satellite bags, sample tubes and donor records have the correct donor name and number; The information on the labels matches with the donor’s information. [[p.5]] 34 Essentials of Blood Banking and Transfusion Medicine Step 2. Select the vein • Select a large, firm vein, preferably in the antecubital fossa, from an area free from skin lesions or scars. • Apply a tourniquet or blood pressure cuff inflated to 40–60 mm Hg, to make the vein more prominent. • Ask the donor to open and close the fist a few times. Step 3. Disinfect the skin • If the site selected for venipuncture is visibly dirty, wash the area with soap and water, and then wipe it dry. • One-step procedure (recommended—takes about one minute): Use a product combining 2% chlorhexidine gluconate in 70% isopropyl alcohol; cover the whole area and ensure that the skin area is in contact with the disinfectant for at least 30 seconds; allow the area to dry completely. • Two-step procedure (if chlorhexidine gluconate in 70% isopropyl alcohol is not available, use the following procedure—takes about two minutes): Step 1—use 70% isopropyl alcohol; cover the whole area and ensure that the skin area is in contact with the disinfectant for at least 30 seconds; allow the area to dry completely. Step 2—use tincture iodine (more effective than povidine iodine) or chlorhexidine (2%); cover the whole area and ensure that the skin area is in contact with the disinfectant for at least 30 seconds; allow the area to dry completely. • Whichever procedure is used, DO NOT touch the venipunc- ture site once the skin has been disinfected. Step 4. Perform the venipuncture Perform venipuncture using a smooth, clean entry with the needle and the needle should be cut off at the end of the proce- dure rather than re-capped. • Ask the donor to open and close the fist slowly every 10–12 seconds during collection. Step 5. Monitor the donor and the donated unit • Closely monitor the donor and the venipuncture site throughout the donation process—look for sweating, pallor [[p.6]] Donor Health Screening, Donor Suitability Evaluation 35 or complaints of feeling faint that may precede fainting; development of a haematoma at the venipuncture site; changes in blood flow that may indicate the needle has moved out of the vein, and needs to be repositioned. • About every 30 seconds during the donation, mix the collec- ted blood gently with the anticoagulant, either manually or by keeping on continuous mechanical mixing instrument. • Remove the tourniquet or release blood pressure cuff after the procedure is complete. Step 6. Remove the needle and collect samples • Collect blood samples for laboratory testing. • Cut off the needle using a sterile pair of scissors. POST-DONATION CARE After a blood donation, following care has to be taken and some instructions have to be given 1. Donor care: After the blood has been collected: • Ask the donor to remain in the chair and relax for a few minutes (10 minutes); • Inspect the venipuncture site; if it is not bleeding, apply a bandage to the site; if it is bleeding, apply further pressure and raise the arm. • Ask the donor to sit up slowly and ask how the person is feeling. • Before the donor leaves the donation room, ensure that the person can stand up without dizziness and without drop in blood pressure. • If donor feels dizzy, ask him/her to lie down. • If fainting and bleeding persists, see that the physician attends him/her. • Inform the staff immediately if any unexpected reactions occur. • Offer the donor some refreshments: Donor should eat and drink before leaving the place. • Ask the donor to drink more fluids for next four hours. • Ask the donor not to smoke or ride/drive vehicle for at least one and a half hours after blood donation. [[p.7]] 36 Essentials of Blood Banking and Transfusion Medicine 2. Blood unit and samples • Transfer the blood unit to a proper storage container according to the blood centre requirements and the product. • Ensure that collected blood samples are stored and delivered to the laboratory with completed documenta- tion, at the recommended temperature, and in a leak- proof, closed container. ADVERSE DONOR REACTIONS Although the donation process is safe and uncomplicated, occasional adverse donor reactions may occur. These can be reduced or avoided by proper donor selection and care. Donors who suffer adverse donor reactions, they may not or they are less likely to donate again. Haematoma formation occurs in 2–3% of the donors. Causes are: 1. Poor or failed venipuncture 2. Needle puncturing the vein twice during the donation 3. Inadequate pressure after the donation In such instances: 1. Apply pressure and a firm bandage 2. Reassure the donor 3. Give relevant contact information to the donor, in case the donor has any further inquiries. 4. Local application of thrombophobe ointment may be advised. Vasovagal episodes and soft tissue injuries (bruises and haematomas at the venipuncture site) are the most common donor reactions. These occur in 1% of the donors. This is due to hypothalamic response resulting in bradycardia, vomiting, sweating, arterial dilatation and a low blood pressure. The majority of these are minor and donor recovers immediately. If fainting occurs after completion of the donation procedure advise rest, elevate foot end, monitor pulse and blood pressure and give plenty of oral fluids. For such donors reassurance should be provided so as to again donate. If symptoms occur [[p.8]] Donor Health Screening, Donor Suitability Evaluation 37 during bleeding procedure, stop bleeding and monitor the vitals. Provide foot end elevation. Fluids may be given orally or IV, if necessary. With severe reactions, donor should not donate again. Young and first time donor are likely to have adverse donor reactions. Causes for vasovagal episodes are: 1. Anxiety 2. Lowered blood volume and other associated causes: • Hypoglycaemia • Lack of fluids • Poor sleep 3. Atmosphere in donation room (hot or humid) Signs and symptoms for vasovagal episodes are: 1. Staring 2. Sighing 3. Pallor or sweating 4. Slow pulse 5. Drop in blood pressure 6. Vomiting 7. Loss of consciousness (occasionally) 8. Convulsions (occasionally)