Why is Vascular Access for Hemodialysis Needed?

This is because it is necessary to establish a reliable access that can be repeatedly punctured and has sufficient blood flow for hemodialysis to proceed smoothly.

Types of Vascular Access

It is divided into long-term vascular access (including autologous arteriovenous fistula and artificial arteriovenous fistula) and temporary vascular access (including long-term double-lumen catheter and temporary double-lumen catheter).

Introduction to Vascular Access

1. Long-term vascular access:

1. Autologous arteriovenous fistula:

It is composed of patients’ own blood vessels. The advantages include fast healing after puncture, low chance of obstruction, infection and blood coagulation, and it is the first choice for long-term hemodialysis access. The surgeon connects the arteries and veins at the far end of the upper extremity of the patient to create a vascular access that allows more venous blood flow and dilates the blood vessels. Vascular access is usually created on the non-dominant arm (left hand).

Possible complications of autogenous arteriovenous fistulas include:

• The thrombus obstructs the fistula and cannot be used.
• Because excessive arterial blood is drained into the fistula, the amount of peripheral blood supply is reduced, resulting in arterial steal syndrome with peripheral ischemia.
• Infection.
• Aneurysm formation may result in rupture or bleeding of the fistulas.
• Venous hypertension causes edema of the limbs with fistulas.

2. Artificial arteriovenous fistula:

Artificial arteriovenous fistulas are needed when the patient's vessels are not well enough for arteriovenous fistula. Patterns include linear or annular artificial fistula implantation. In principle, consider the position of the non-dominant left hand first. Common complications are similar to autologous arteriovenous fistulas. Besides, the incidence of complications is higher than autologous arteriovenous fistula.

2. Temporary vascular access (double-lumen catheter)

1. Long-term double lumen catheter (Permcath)

Silica-based catheters are inserted surgically and fixed to subcutaneous tunnels by a ring at the back end. The catheter is usually placed in the internal jugular vein, with its top in the lower end of the superior vena cava or the right atrium. A chest X-ray will be taken on the day after implantation to make sure the right position of the catheter, which can be used immediately after implantation if the wound is good. Under good maintenance, the expiration date of the catheter is about 6 months. Infection or catheter obstruction is the most frequent causes which leading to long-term double-lumen catheter failure.

2. Temporary double-lumen catheter

The catheter is placed by a physician in the ward or hemodialysis room. It is usually placed in the femoral vein of the in the groin and inner thighs for emergency and short-term hemodialysis. The infection rate and obstruction rate are high, so the duration of placement should not exceed 2 weeks.