PHL+118+Week+3+2024

Primary goal: obtain venous blood quickly, safely, and with minimal patient discomfort.
Upper extremities are safest & easiest because veins are superficial, well-anchored, and away from major nerves/arteries.

Median cubital vein
• Lies in the antecubital fossa (inner elbow).
• Large, well-anchored, seldom rolls → first-choice site.
• Typically positioned over the bicipital aponeurosis, protecting the brachial artery & nerve.
Cephalic vein
• Runs along the lateral (thumb) side of forearm.
• Easier to access in obese patients.
• More superficial → may roll; proper anchoring is critical.
Basilic vein
• Medial (pinky) side, close to brachial artery & median nerve.
• Use only when other sites unavailable; increased risk of arterial puncture or nerve injury.

Brachial, radial, & ulnar arteries, plus the deep palmar arch, course near these veins.
Understanding 3-D location decreases inadvertent arterial puncture.

Hematoma: may yield hemolyzed/contaminated sample; painful; risk of further bleeding.
Scar or extensive burn: impaired circulation, altered skin integrity, painful, poor healing.
Edema: diluted specimen; difficult to locate vein; risk of fluid leakage.
Fistula or vascular graft (dialysis pts): NEVER use without explicit nephrology order.
Post-mastectomy arm: lymphatic compromise → infection & lymphedema risk.
Arm with active IV infusion
• If unavoidable, draw below the IV cannula & confirm no transfusion is running.
• Document that specimen may be slightly diluted.

Capillaries = microscopic vessels connecting arterioles & venules; site of $\text{O}<em>2$ / $\text{CO}</em>2$ exchange.
Capillary blood resembles arterial blood (oxygen-rich) yet contains venous characteristics—useful for POCT.

Preferred: fleshy pad of 3rd (middle) or 4th (ring) finger, non-dominant hand, slightly off-center.
Acceptable: Earlobe (less common today).
Avoid:
• Thumb (callused)
• Index finger (dense nerve endings)
• 5th finger (thin tissue, bone proximity).
Keep puncture ≥ 2 mm distal to nail bed; never through visible injury/infection.

Medial & lateral plantar surface of the heel (birth – 12 months).
Hold infant securely; legs dependent to enhance blood flow.
Warm heel 3–5 min with moist towel ≤ $42\ ^\circ\text{C}$ ( $108\ ^\circ\text{F}$ ).
NO adhesive bandage if <2 yrs (choking hazard).

Hand hygiene.
Gather supplies (spring-loaded or manual lancet, alcohol pad, gauze, micro-hematocrit tube, clay sealer, gloves, sharps container, documentation tools).
Identify & consent patient; seated or supine.
Don gloves.
Select site → warm by brisk rubbing.
Clean with alcohol; air-dry to prevent hemolysis.
Remove lancet shield; anchor finger/heel; swift puncture (avoid center of finger pad).
Dispose lancet immediately (sharps).
Wipe first drop (tissue fluid contamination).
Collect free-flowing second drop into micro-tube; may gently massage (do NOT milk aggressively → hemolysis).
Seal tube end with clay.
Apply gauze; patient maintains pressure until bleeding stops.
Bandage if appropriate (not for infants).
Assess dizziness/vasovagal response.
Remove gloves, perform hand hygiene.
Document: date, time, site, patient tolerance, specimen labeling.

Small needle with plastic “wings” attached to 6–12 inch tubing.
Gauge options: 21, 23, 25 (smaller number = larger bore).
• $25\text{ G}$ ↑ risk haemolysis.

Cost: ~ $\$70–80$ per 50 vs $\$30–40$ for 48 straight needles.
↑ risk of hemolysis with very small gauges (may compromise K⁺, LDH, CBC values).
Not first-line in cost-sensitive settings; use justified by patient safety/comfort.

Many sets include in-line safety slide or retractable needle to meet OSHA needlestick standards.