Hemodialysis

A hemodialysis patient's vascular access is their lifeline — and the wrong blood pressure cuff placement or missed bruit can end it. Knowing which access type dictates which nursing actions is a guaranteed NCLEX topic.

Three types of vascular access exist for hemodialysis: arteriovenous fistula (AVF), arteriovenous graft (AVG), and central venous catheter (CVC). The AVF is the gold standard — a surgical anastomosis of a native artery to a vein, typically in the nondominant forearm (radiocephalic). It requires 2–6 months to mature before use but has the lowest infection and clotting rates. The AVG uses synthetic tubing to bridge artery and vein, can be used within 2–4 weeks, but clots and infects more often. The CVC (typically internal jugular) is used for urgent or temporary access and carries the highest infection risk. For AVF and AVG, you assess patency every shift by palpating for a thrill (continuous vibration) and auscultating for a bruit (whooshing sound). Absence of either signals clotting — notify the provider immediately. The access arm is strictly protected: no blood pressures, no venipunctures, no tourniquets, no restrictive clothing or jewelry. Elevate the extremity post-operatively to reduce swelling. Teach the patient to perform hand exercises (squeezing a rubber ball) to promote AVF maturation.

Key Distinctions

A thrill is felt (palpation), a bruit is heard (stethoscope) — students reverse these constantly. Don't confuse AVF maturation time (2–6 months) with AVG usability (2–4 weeks); the NCLEX tests which access is available soonest. The internal jugular vein is preferred over the subclavian for CVC placement because subclavian catheters risk central venous stenosis, which can compromise future AVF creation in that extremity.

Clinical Pearl

No BP, no sticks, no squeeze on the access arm — treat it like the patient's most valuable possession, because it is.

Procedure & Complications

Hemodialysis removes waste and excess fluid by pumping blood through an extracorporeal circuit across a semipermeable membrane against dialysate. A typical session runs 3–4 hours, three times per week. The most common intradialytic complication is hypotension, caused by rapid ultrafiltration removing fluid faster than it can shift from interstitial to intravascular space. Nursing response: stop ultrafiltration, place the patient in Trendelenburg (unless contraindicated), and administer a normal saline bolus per protocol. Dialysis disequilibrium syndrome occurs when urea is cleared from blood faster than from brain tissue, creating an osmotic gradient that pulls water into the brain — presenting as headache, nausea, seizures, and altered LOC, most commonly during first treatments or when BUN is very high. Other complications include muscle cramps (from rapid fluid and electrolyte shifts), air embolism (sudden dyspnea, chest pain — clamp the line, position patient on left side in Trendelenburg), and blood loss from circuit disconnection. Heparin is used throughout the session to prevent clotting in the circuit, so monitor for bleeding from the access site, gums, and mucous membranes. Post-treatment, monitor weight (expect 0.5–1.5 kg loss per session), vital signs, and access site.

Key Distinctions

Don't confuse dialysis disequilibrium syndrome (cerebral edema from rapid urea clearance — headache, seizures) with uremic encephalopathy (gradual confusion from untreated uremia). Students mix up air embolism positioning (left side, Trendelenburg to trap air in right ventricle) with pulmonary embolism positioning (elevate HOB). Hypotension during dialysis is treated with saline and stopping ultrafiltration — not by discontinuing the entire treatment.

Clinical Pearl

Air in the line? Think LEFT and LOW — turn the patient onto the left side, head down. Trapping air in the right ventricle keeps it out of the lungs.