Renal Replacement Therapy & Dialysis

50 question-and-answer flashcards covering principles, modalities, complications, and management strategies of renal replacement therapy and dialysis.

What transport process in dialysis moves small molecules (<500 Da) down a concentration gradient?

Diffusion

Which mechanism is the main means of eliminating urea and creatinine during dialysis?

Diffusion

In ultrafiltration, what substance is primarily transported across the membrane?

Water

The rate of ultrafiltration is chiefly determined by which gradient?

Pressure gradient across the membrane

What dialysis transport process drags solutes with water under pressure and is nicknamed “solvent drag”?

Convection

Convection is especially useful for removing particles of what general molecular-weight range?

Mid- to large-weight solutes (>500–1,000 Da)

Which dialysis modality employs both diffusion and convection for solute/fluid removal?

Hemodialysis (HD)

For patients with CKD stage V, hemodialysis is usually required for how long?

Lifelong, unless they receive a kidney transplant

Emergent hemodialysis used in acute kidney injury (AKI) is typically __.

Temporary

How many times per week do most in-center hemodialysis patients receive treatment?

Three times per week (e.g., Monday/Wednesday/Friday or Tuesday/Thursday/Saturday)

Home hemodialysis is commonly performed how many times weekly?

Five to six times per week

Which long-term vascular access for HD is generally preferred because of superior blood flow, durability, and lower infection risk?

Arteriovenous (AV) fistula

Approximately how long does an AV fistula need to mature before first use?

1–2 months

What is an AV graft in the context of dialysis access?

A synthetic conduit surgically connecting an artery to a vein

AV grafts usually require how long before they can be cannulated?

2–3 weeks

Which dialysis access device can be used immediately but has the highest complication and shortest survival rates?

Central venous catheter

Removing fluid too rapidly during HD can lead to which acute complication?

Intradialytic hypotension

What is the first-line bolus therapy for hypotension during HD?

Normal saline 100–250 mL

Which oral α-agonist is often given 30 minutes before HD to prevent hypotension?

Midodrine 2.5–10 mg orally

Name an oral prodrug of norepinephrine that may be given 1 hour before HD to prevent hypotension.

Droxidopa 100–600 mg orally

Besides medications, list one non-pharmacologic strategy to prevent HD-induced hypotension.

Prolong the dialysis session or omit antihypertensive doses on dialysis days

How are catheter-related infections in HD generally managed?

Antibiotics (and catheter removal if indicated)

Which thrombolytic agent can be instilled at 2 mg/2 mL per lumen to clear a clotted HD catheter?

Alteplase

What reteplase dose is used intraluminally for HD catheter thrombosis?

0.4 units in 0.4 mL per lumen, aspirated after 20–30 min

Why do all HD patients need water-soluble vitamin supplements?

HD removes water-soluble vitamins, causing deficiency

Regular multivitamins are NOT recommended for HD patients because they __.

Do not contain adequate amounts of water-soluble vitamins lost during dialysis

In peritoneal dialysis, what cavity holds the dialysate?

The peritoneal cavity

The semipermeable membrane in PD is formed by what anatomical structure?

The peritoneal membrane lining the abdomen

Which transport mechanism dominates solute removal in PD?

Diffusion (with some ultrafiltration for fluid)

What osmotic agent in most PD solutions can cause glucose load and hyperglycemia?

Dextrose

Name one strategy to manage hyperglycemia caused by PD solutions.

Add intraperitoneal insulin or switch to icodextrin (a glucose polymer)

Cloudy effluent with or without abdominal pain in a PD patient suggests what complication?

Peritonitis

What is the preferred route for antibiotics when treating PD-associated peritonitis?

Intraperitoneal administration

Purulent drainage at the PD catheter exit site most likely indicates __.

Catheter-related infection

Continuous ambulatory peritoneal dialysis (CAPD) requires the patient to perform exchanges how?

Manually throughout the day

Automated peritoneal dialysis (APD) utilizes what piece of equipment to perform exchanges?

An automated cycler

During APD, individual dwell times are typically how long?

1–2 hours

Over the same time period, which modality removes drugs more efficiently—HD or PD?

Hemodialysis removes drugs more efficiently

Which modality carries a higher risk of intradialytic hypotension—HD or PD?

Hemodialysis

Systemic anticoagulation is routinely required for which dialysis modality?

Hemodialysis

Does peritoneal dialysis require a central venous line?

No

Which dialysis modality is generally simpler for a patient to self-administer?

Peritoneal dialysis

Hemodialysis can be used for AKI management, whereas PD generally __.

Is not used for acute kidney injury

Which modality usually demands more total daily time from the patient—PD or thrice-weekly HD?

Peritoneal dialysis

In diffusion, how does molecular size influence transport speed across the membrane?

Larger molecules diffuse more slowly

Another name for convection in dialysis, emphasizing solute drag, is __.

Solvent drag

What pump in an HD machine propels blood through the extracorporeal circuit?

Blood pump

Which component in the HD circuit monitors arterial-line pressure for safety?

Arterial pressure monitor

What device detects air before blood returns to the patient during HD?

Air detector

Which pump delivers dialysate on the other side of the HD membrane?

Dialysate pump

What is currently the most commonly used treatment modality for end-stage renal disease (ESRD)?

Hemodialysis

What two transport mechanisms together account for solute and fluid removal during hemodialysis?

Diffusion and convection