Hemodialysis Theory and Principles

Practice flashcards covering neuropathy, fluid dynamics, ultrafiltration rates, and infection control in hemodialysis.

What is Neuropathy and what are its signs and symptoms?

Neuropathy is nerve damage that occurs in the peripheral areas of the body. Signs and symptoms include numbness, burning, pins and needles sensations, weak muscles, and erectile dysfunction in men.

What is Pruritis and what are its common causes?

Pruritis is a form of pain characterized by itching. Its causes include dry skin, allergic reaction to a medication or chemical, and mineral bone disease.

Describe the three steps of the 'waterfall effect' during fluid shift in dialysis.

1. Dialysis pulls some water out of the blood. 2. Water between the cells (extracellular space) shifts into the blood (vascular space). 3. Water inside the cells (intracellular space) shifts into the space between the cells (extracellular space).

What is the formula for Ultrafiltration Rate (UFR) and its suggested limit for plasma refill?

The UFR is measured in $\text{mL/kg/hr}$. The suggested plasma refill rate is between $5$ and $10\,\text{mL/kg/hr}$.

What is organ stunning and how can it be avoided?

Organ stunning occurs when blood volume shrinks and blood pressure drops. It can be avoided by lowering the UFR, longer treatments, cooler dialysate, and oxygen.

What is the maximum UFR threshold monitored by Medicare?

Medicare monitors to ensure UFRs are kept below $13\,\text{mL/kg/hr}$.

How does convection increase the removal of wastes in dialysis?

Convection increases waste removal by dragging solutes through the dialyzer membrane with the water, a process known as solvent drag.

Where are more solutes dragged through the dialyzer during convection and why?

More solutes are dragged through the arterial end of the dialyzer because it has the highest concentration of wastes.

In terms of fluid dynamics, how do pre-pump and post-pump pressures differ in the blood circuit?

Pre-pump pressure is usually negative because the pump is pulling blood from the patient. After the pump, the pressure is positive because the pump is pushing the blood to the dialyzer.

What components are included in the dialysis blood circuit?

The circuit includes the blood pump, blood tubing, heparin pump, dialyzer, and safety monitors.

How does positive blood pressure change as it passes through the dialyzer?

The highest positive pressure is in the arterial header of the dialyzer. Pressure decreases as blood passes through, leaving the least positive pressure as it leaves via the venous header.

Where is negative dialysate pressure highest in the dialyzer?

Dialysate pressure is highest (most negative) at the venous end of the dialyzer.

What is adsorption in the context of dialysis?

Adsorption is a build up of a blood protein, making a thin layer inside the dialyzer membrane. This film can slow the rate of diffusion and osmosis, making treatment less efficient.

What is the statistical significance of infection for hemodialysis patients?

Infection is the third most common cause of death in patients on hemodialysis.

What are the potential sources of pathogen spread in a dialysis setting?

Pathogens can be spread by team members, patients, visitors, water, equipment, dialysate, and air.