One Arm, Two Procedures, Three Tubes
Ms. Tran, 58, has orders for a 12-lead ECG and a stat draw of light blue (PT/INR), gold/SST (BMP), and lavender (CBC) tubes. Two years ago she had a right modified radical mastectomy with axillary node dissection and has chronic lymphedema in that arm. Her left antecubital fossa has a running IV of 0.9% normal saline, and she has a pacemaker generator in the left upper chest. She has a documented allergy to adhesive tape. She tells you, 'Just use the right arm - the left one's sore, and they always have trouble there anyway.' The nurse is charting at the desk.
1. She has asked for the right arm. Where do you draw, and in what order, with what technique?
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The right arm is not available, and this is not negotiable. After axillary node dissection, the arm has impaired lymphatic drainage; venipuncture there risks chronic lymphedema and infection. That restriction is lifelong, and 'the last person did it' does not make it safe.
Left arm, with a plan for the IV:
- Best choice is a vein in the left hand or forearm below the IV site, or ask the nurse to pause the infusion briefly. Drawing above a running line risks dilution. Never draw coagulation studies from a line containing heparin.
- Use a 21-gauge butterfly for these three tubes; a 23-gauge on a multi-tube draw invites hemolysis.
Order of draw:
- Discard tube (2–5 mL, non-additive). With a butterfly, air in the tubing would otherwise underfill the citrate tube.
- Light blue - fill exactly to the line and invert 3–4 times. An underfilled citrate tube has the wrong blood-to-anticoagulant ratio and falsely prolongs the PTT.
- Gold/SST - invert, allow full clot time.
- Lavender - invert gently; never shake.
2. How do you set up the ECG given the pacemaker, the mastectomy, and the tape allergy?
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Prep: alcohol rub, dry, clip hair if needed rather than shaving, no lotion. Use hypoallergenic electrodes and no tape on the skin - if something must be secured, use paper tape or secure it to the lead wire, not the skin.
Limb leads: place them on the shoulders and hips (or upper arms and lower legs) rather than the chest. Keep the left-arm lead off the pacemaker generator site in the left upper chest; the right-sided leads should avoid the mastectomy scar and the lymphedematous arm.
Precordial leads: V1–V6 in standard positions, shifting slightly to avoid scar or irradiated tissue. Document any deviation from standard placement - a shifted lead changes the tracing and the reader needs to know.
Pacemaker considerations:
- Keep the electrodes at least a few centimeters from the generator.
- Expect pacing spikes; many machines filter or miss them, so tell the interpreting clinician that the patient has a pacemaker and note it on the tracing.
- Compare with any prior ECG - a baseline is more useful than one isolated strip.
- A pacemaker is not a reason to skip the ECG, but it is a reason to label it.
3. She insists on the right arm again and says the last tech had no problem. How do you respond, and what if she refuses the left arm entirely?
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Explain in plain language, once: 'The lymph nodes under that arm were removed with the surgery, so fluid cannot drain the way it should. A needle stick there can cause permanent swelling or an infection that is very hard to treat. I am not refusing to help you - I am refusing to hurt you.'
Then solve the real problem: her left arm is sore and has been a hard stick. Warm the arm, look at the hand and forearm veins, ask the nurse about a topical anesthetic if ordered, and consider whether the nurse or the IV team should do this draw.
If she refuses the left arm entirely:
- Do not draw from the right arm. Consent does not make a harmful act safe, and a prior tech's choice is not a policy.
- Stop, notify the nurse, and let the ordering provider and nurse discuss alternatives - a port or central line draw, or rescheduling.
- Document the refusal, what you explained, who was notified, and the time. Do not deceive her, do not draw while she is distracted, and do not document a result you did not obtain.