Renal failure

[Munkeh]

Why do some people go into respiratory failure as a cause of acute renal failure happening?

[theprof]

I'll start by saying that as you're probably aware, most people go into renal failure as a result of respiratory failure!

Anyhow, the reason respiratory failure does occur in some patients is basically down to electrolyte abnormalities in the body due to the renal failure. Potassium and Magnesium are the main electrolytes involved, but others also play a part.

The electrolyte imbalance seriously compromises fluid clearance from the lungs. In turn, the build-up of fluid leads to the respiratory failure.

If you need a more complex explanation, let me know.

[Munkeh]

Hey thanx theprof. Im a icu nurse just recently strated working there, im doing a respiratory self teaching pack.......i always thought that the reason people go into respiratory faliure who have renal faliure is due to metobolic acidosis?! Don't the kidney produce sodium bicarbonate to buffer up excess Ph in the blood?? So if someone has renal failure do they stop producing soduim bicarb... i could just be talking a load of nonsense! lol!

[theprof]

Yes, you�re absolutely right - the reason that respiratory failure occurs is because of metabolic acidosis. This metabolic acidosis occurs because renal failure affects the ability of the kidneys to produce bicarbonate.

Renal failure also results in the inability of the kidneys to regulate other electrolytes, fluid and the acid-base balance in the body. This included the inability to concentrate the urine whilst maintaining an electrolyte homeostasis. In turn, this leads to volume and electrolyte overload, caused by salt and water intake exceeding losses and excretion leading to pulmonary uraemia and pulmonary oedema. These conditions are potentially fatal. Respiratory acidosis occurs as a result of the pulmonary oedema.

Bicarbonate production is reduced or prevented altogether in renal failure so it�s not possible to buffer against the fall in metabolic pH.

Bicarbonate therapy is not without its own problems. Concentrated solutions can cause extracellular fluid volume expansion, which can cause pulmonary oedema itself. Isotonic solutions can be unpredictable. The only certain methods of correcting acidosis are haemodialysis or haemofiltration.

Sorry, I was a bit vague earlier � I�d have gone into more detail if I�d known you were a nurse!