Interventional Radiology Procedures: Tunneled Hemodialysis Catheter Placement (Indications For Hemodialysis)

OVERVIEW

While the actual placement of a tunneled hemodialysis catheter is a technical procedure conducted by interventional radiologists, it is important to understand the basics of why such a catheter is needed in the first place. This begins with understanding the indications for hemodialysis. 

A fundamental piece of medical knowledge is understanding the indications for patients to receive dialysis (image source).
FUNDAMENTAL PREMISE BEHIND DIALYSIS

Before covering too many specifics, it is important to appreciate that fundamentally the role of dialysis is compensate for a loss of renal function. This can take many different forms and can occur over various different timeframes, however the base principle remains the same. The renal system performs important physiological tasks, and when it becomes compromised, dialysis can be used to make sure that the patient’s life is not put in jeopardy from the loss of renal function.

The renal system is very important in performing a wide range of physiological tasks in the human body. When it becomes impaired, dialysis may be required to compensate for the loss of renal function (image source).
ABSOLUTE/ URGENT INDICATIONS FOR DIALYSIS

Let us begin with some of the urgent indications for dialysis. These are the ones that are not ambiguous, and when detected require that all parties involved make sure that the patient is able to receive dialysis.

UREMIA AND ASSOCIATED SIGNS/SYMPTOMS/CONDITIONS

A large role of the kidneys is to exert waste products like uric acid. When the amount of uric acid in the serum increases patients may become symptomatic as a result. Here are some of the manifestations that can be absolute/urgent indications for initiating dialysis.

  • Uremic pericarditis
  • Uremic pleurites
  • Uremic encephalopathy: sometimes this may be a decline in mental status in a patient with elevated BUN which has no other explanation.

SEVERE HYPERKALEMIA

An important role of the kidneys is to excrete potassium from the serum. In the absence of their function serum levels of potassium can reach dangerous levels. Generally speaking when concentrations rise above 6.5 mEq/L  and can not be controlled by medical management then patients may require emergency dialysis to correct electrolyte abnormalities immediately.

Sometimes a patient’s hyperkalemia may not be too severe in the moment, however given a loss of renal function combined with rapidly rising potassium levels dialysis may need to be initiated emergently.

SEVERE METABOLIC ACIDOSIS

The renal system is also responsible for maintaining (in part) the acid base balance in the body. A commonly used threshold for diagnosing severe metabolic acidosis can be a serum ph of <7.1 in the setting of known renal impairment, and this can be an urgent indication to initiate dialysis.

SEVERE OR REFRACTORY FLUID OVERLOAD

In the absence of proper renal function, patients will be unable to excrete fluid from the body expediently and can very easily become fluid overloaded. This is especially challenging when the medical management for certain conditions caused by loss of renal function (i.e. hyperkalemia) involves giving patients large volumes of IV fluids.

Sometimes the patient will require dialysis simply to just remove off excess fluid that may need to be removed quickly, or fluid that has not been able to be removed with medical management.

COMMON INDICATIONS FOR DIALYSIS

The themes revolving around common indications for dialysis are related to the urgent/absolute indications discussed above. They include:

  • Declining nutritional status: uremia can manifest by causing nausea, vomiting, and anorexia in certain populations of patients. This is actually a very common reason to initiate dialysis in patients with chronic kidney disease.
  • Fatigue/malaise: aslo a byproduct of uremia in certain patient populations.
  • Persistent/refractory volume overload: in certain patients it may be more practical to begin treating volume status with dialysis given impaired renal function. C
  • Mild cognitive impairment: it can be difficult to ascertain why a patient may have cognitive impairment sometimes, and in certain contexts patients with chronic renal disease may have dialysis initiated to exclude the possibility that uremia is responsible for changes in mental status.
  • Refractory acidosis, hyperkalemia, and hyperphosphatemia that is difficult to control with medical management alone: at a certain point patients with chronic kidney disease may not have these conditions effectively controlled with medical management alone and can require the initiation of dialysis.

 

Page Updated: 03.31.2019