15.2 Nerve, Arterial, Hematoma & Related Injuries

15.2 Nerve Injury, Arterial Puncture, Lymphedema, Hematoma & Related Injuries

Quick Answer: Stop immediately for electric/shooting pain (possible nerve). For arterial puncture, remove the needle and hold firm prolonged pressure. Never use a fistula arm or a mastectomy-side arm without physician approval. Stay inside acceptable antecubital and approved alternate sites, limit pediatric volumes, and treat every hematoma as a signal to stop probing.

Domain VI-F asks you to prevent and manage procedure-related harm. These complications are rarer than vasovagal reactions but carry higher legal and clinical stakes. The RPT exam rewards site selection judgment as much as "what to do after it happens."

Nerve Injury

Cutaneous sensory nerves — the lateral and medial antebrachial cutaneous nerves, which run superficially beside the cephalic and basilic veins — are the ones most often injured during venipuncture. The deeper median nerve (a mixed motor and sensory nerve near the basilic/brachial region) is struck less often but causes far more serious injury. Either can be contacted by the needle tip or compressed by a hematoma.

Classic patient report: sudden sharp, electric, burning, or shooting pain that may radiate down the forearm into the hand or fingers—often out of proportion to a normal stick. Numbness or tingling may follow.

Correct response:

1. Stop the attempt immediately—do not redirect or dig.
2. Remove the needle and activate safety.
3. Apply pressure to the site.
4. Document the patient's exact words and symptoms.
5. Notify the nurse/provider; advise the patient that symptoms should be evaluated if they persist.
6. Do not attempt another stick in the same tract.

Prevention: Prefer the median cubital and cephalic veins when available; approach the basilic with caution because of proximity to the median nerve and brachial artery. Keep the needle angle shallow (commonly about 15–30 degrees for antecubital venipuncture), avoid excessive lateral probing ("fishing"), and never stick blindly. The ventral (palm-side) wrist is a high-risk nerve zone and is not an acceptable routine site.

Arterial Puncture

Accidental arterial entry usually involves the brachial artery (deep to the basilic area) or, less often, the radial artery at the wrist if an inappropriate site is chosen.

Response: Remove the needle at once. Apply firm, direct pressure for a prolonged period—many facilities specify at least 5 minutes (longer if the patient is on anticoagulants) and then recheck. Do not use the specimen for tests that require venous blood unless the lab specifically accepts and labels an arterial sample (routine chemistry panels are typically venous). Notify the clinician; monitor for expanding hematoma, numbness, or cool distal extremity—escalate if perfusion is questioned.

Exam trap: Do not apply a loose gauze and walk away. Arterial bleeds need sustained pressure and observation.

Hematoma

A hematoma is blood leaking into tissues around the puncture. Causes include:

• Needle going through the back wall of the vein
• Excessive probing
• Failure to release the tourniquet before needle withdrawal
• Inadequate post-draw pressure or early bending/heavy use of the arm
• Fragile veins (elderly, steroid use, coagulopathy)

Management: Discontinue the attempt if a hematoma forms during the stick. Apply firm pressure, then a pressure bandage per policy; cold pack may reduce swelling after bleeding is controlled. Warn the patient about expected bruising color changes and when to seek care (expanding mass, severe pain, numbness, signs of infection).

Large hematomas can secondarily compress nerves—another reason not to "push through" a blowing vein.

Lymphedema and Mastectomy Rules

After axillary lymph node dissection or mastectomy, the ipsilateral arm is at risk for lymphedema (chronic swelling from impaired lymphatic drainage). Venipuncture, IV starts, and blood pressure cuffs on that side can worsen or trigger swelling and infection risk.

Standard rule taught for certification exams:

• Do not draw blood from the arm on the side of a mastectomy / lymph node dissection unless a physician has specifically authorized it (for example, when both sides are affected and a documented exception exists).
• Prefer the opposite arm. If bilateral mastectomy, follow written orders / facility policy (often hand veins or physician-directed site).
• Ask during assessment: "Have you had breast surgery, lymph nodes removed, or swelling in either arm?"

Treat lymphedema itself as a hard stop for that limb—do not stick edematous tissue.

Fistula, Graft, and Other Restricted Arms

An AV fistula or graft used for hemodialysis is a surgically created high-flow access. It is never a phlebotomy site.

Drawing from a fistula can damage the access, cause prolonged bleeding, and threaten the patient's dialysis lifeline—this is a classic "never event" style exam item.

Collecting Outside Acceptable Areas

Acceptable adult venipuncture sites are primarily the antecubital fossa veins (median cubital preferred, then cephalic, basilic with caution) and approved alternate sites such as dorsal hand veins when antecubital sites are unsuitable. Capillary sites follow separate maps (finger for adults/older children; medial/lateral plantar heel for infants).

Generally unacceptable for routine phlebotomy:

• Ventral wrist / anterior wrist (nerves and tendons)
• Feet and legs in adults without physician order (clot risk, especially in diabetics)
• Femoral vein (not a phlebotomist's independent site)
• Arm with fistula, significant edema, infection, or rash at the site
• Sites above an IV without following policy

If you cannot obtain blood from acceptable sites after allowed attempts (often two), stop and escalate—do not invent a risky site.

Iatrogenic Anemia and Neonatal Volume Limits

Iatrogenic anemia means anemia caused by medical blood loss—repeated laboratory draws. Critically ill adults can lose significant volume over days; neonates and infants are most vulnerable because total blood volume is small.

Approximate physiology useful for exams:

• Neonatal/infant blood volume is often estimated around 80–100 mL/kg (varies by age).
• Safe sampling limits in pediatric research and hospital policy commonly fall near 1–5% of total blood volume in 24 hours, with many U.S. facilities using charts based on mL per kg (examples in published guidelines include maxima on the order of about 2–3 mL/kg in a day—always follow your institution's posted chart).

Phlebotomist responsibilities:

• Use the smallest appropriate tubes and combine tests when the lab allows add-ons from one draw.
• Prefer capillary microsamples when ordered and clinically appropriate.
• Check cumulative volumes for NICU/pediatric patients before collecting large panels.
• Never "extra fill" tubes "just in case."
• Communicate with nursing when orders would exceed the day's limit so providers can prioritize tests.

A 2 kg neonate may have only ~160–200 mL total blood volume; removing several milliliters repeatedly quickly becomes a transfusion-driving loss.

Putting It Together: Decision Table

RPT Exam Focus

VI-F items often mix recognition (what the complication looks like) with site rules (mastectomy, fistula, wrist). When two answers both sound caring, choose the one that stops harm and follows the anatomic restriction. Explanations on the exam will track content—nerve pain means stop; arterial means pressure; restricted arms mean choose another site—not vague "reassure the patient and continue."