Challenges of the oncology draw

Jan. 1, 2011

Because obtaining blood from cancer patients presents unique challenges, MLO invited three experts to discuss solutions:

Dennis J. Ernst, MT(ASCP), director, Center for Phlebotomy Education, Corydon, IN; Andra Hill, medical laboratory assistant, Calgary Laboratory Services, Calgary, Alberta, Canada; and Lionel Lee, laboratory assistant, Calgary Laboratory Services at the Peter Lougheed Centre, in Calgary.

Challenge #1: Veins are difficult to find. Ernst's solution: Chemotherapy is tough on the vasculature of the circulatory system. Oftentimes patients' veins are fragile, small in diameter, and difficult to anchor. For those who draw from this population, a combination of the right equipment and the right technique is essential for a successful puncture. Small veins require small needles. Hence, use needles no larger than 23-gauge. Because oncology patients have varying degrees of muscle loss, their veins are not supported by tissue and have a tendency to roll. Therefore, anchoring veins properly is essential. Anchoring, however, should not involve anchoring above and below the intended puncture site. Placing the index finger above the site puts the collector at risk of an accidental needlestick. Instead, anchor firmly from below the intended puncture site. Extend the elbow fully so that the veins rise to the uppermost part of the antecubital area to facilitate palpation. If the patient is arthritic or has limited range of motion in the joint, however, do not employ this technique. Rather, extend the arm as much as possible without hurting the patient.

Challenge #2: Veins are hard to access. Ernst's solution: Oncology patients' fragile veins are prone to collapse, so be sure to select the right equipment for the puncture. Use syringes and 23-gauge needles or 23-gauge butterfly needles with syringes attached to control the negative pressure applied to the vein's interior. If a tube holder is used instead of a syringe, the full vacuum of the tube is likely to collapse the fragile veins. Once accessed, use only gentle pulling pressure on the plunger of the syringe to avoid vein collapse. Should the vein collapse anyway, release the plunger, allow the vein to refill, and pull back even more gently until sufficient sample has been obtained. Collectors who draw from oncology patients often get smaller quantities of blood than they had hoped for. Make sure phlebotomy trays and outpatient draw stations are stocked with a wide variety of smaller volume tubes to help ensure the volume collected can be evenly distributed to multiple tubes without any of them being underfilled.

Challenge #3: Veins are tiny or do not exist. Lee's solution: Oncology patients present this challenge due to chemotherapy and weight loss associated with cancer. Patients lose a lot of their fatty tissues, causing their upper extremities (hands and fingers) to feel cold. To overcome this challenge, warm the phlebotomy location areas. Use a heel warmer or hot blanket, available in some hospital wards, to wrap up the patient's hand from the fingers to above the elbows and if possible, ask the patient to warm his hands under running warm water. Advise patients to wear warm clothing when they go to the lab for blood collections.

Challenge #4: Prolonged bleeding from venipuncture sites. Ernst's solution: Depending on the type of cancer, oncology patients may be depleted of platelets. As a result, venipuncture sites can continue to bleed long after the draw is complete. Never release a patient until you are assured bleeding has stopped. Hold the site as long as necessary. Also consider providing patients with post-venipuncture care instructions, such as not using the arm to lift anything and not cradling a purse in the bend of the arm. Either of these motions can reopen the puncture, resulting in a hematoma and related complications.

Challenge #5: Patients' hands are swollen. Lee's solution: Hands become swollen due to edema or IV fluid escaping into the interstitial area around a needle-poke site. Press the intended phlebotomy location with at least one or two fingers. This helps to push the fluids away, thus making the veins visible.

Challenge #6: Mastectomy patients. Hill's solution: Only the side that does not have a mastectomy can be used. Since the allowed arm is used for both chemotherapy and phlebotomy, the veins can be scarred and hardened. Try to use a vein that has not been used for chemotherapy. Patients who want to “save” their good veins for treatments will often request this. Veins left to work with are small and not a phlebotomist's first choice: the basilic vein or hand veins. In the case of a patient with a double mastectomy, you cannot draw blood from either arm without permission from the ordering physician. Sans approval, do a foot poke.

Challenge #7: Oncology patients can be high acuity. Ernst's solution: Few patient populations require as much compassion and patience as oncology patients. Chemotherapy can be so debilitating that merely positioning them to the best advantage can be a challenge. They may not even have enough strength to clench a fist. All of this makes them a phlebotomist's greatest challenge. It takes a special person with solid training to draw from this population successfully, compassionately, and consistently.

See related article Advances in technology improving safety and efficiency in blood-sample draw

Karen Lynn is a freelance medical writer.