Cardiac question

Helps me to think of renal failure as stemming from either prerenal, renal (intrinsic), or postrenal etiology.

Prerenal causes are related to decreased perfusion of the kidney - usually either cardiovascular issues or extracellular volume depletion. (50%-80% of acute renal failure)

Intrinsic renal etiology means that the problem lies in pathology of the kidney itself, such as glomerulonephritis, lupus, or Goodpasture's syndrome.

A postrenal cause means that the kidney is not diseased and is being adequately perfused, but there's an obstruction somewhere down the line (ureters, bladder, urethra).

Renal failure could come from any surgery, as people are NPO prior and then tend to lose fluids intro-operatively.

Notes from my renal lecture:

Prerenal renal failure: Conditions that diminish blood flow to the kidneys. Decreased blood flow leads to decreased perfusion and filtration. Caused by anything that causes intravascular volume depletion: dehydration, hemorrhage, heart failure, shock, burns.

Examples: Hypovolemia, acute blood loss, cardiogenic shock.

Volume depletion (prerenal) is the most common cause of acute renal failure, accounting for 70% of all cases.

Low blood pressure--Intratubular pressure will exceed the glomerular hydrostatic pressure, and glomerular filtration will cease. Low, no urinary output.

SS: hypotension, orthostatic hypotension, tachycardia, urinary output 1.1, BUN > 18, lethargy.

Treatment: reverse the underlying cause--establish normal intravascular volume, increase blood pressure, maintain cardiac output.

What will be the treatment? Hydration with intravenous fluids.

IV fluid bolus of 500 - 1000cc NS over an hour period. Treat heart failure. Stop hemorrhage. This form of ARF is reversible in most cases if caught early enough.

Prevention is the best treatment!!! Early interventions to restore circulating volume, improve cardiac output, reestablish blood pressure may prevent progression to renal failure.

Prerenal disease, if not promptly treated, can lead to kidney damage (intrarenal disease). Prolonged, untreated hypoperfusion can lead to severe ischemic injury ("shocked" kidney) and damage to nephrons.

I would likely say that if it is an emergency repair then perfusion to the kidney has been compromised by shock. Even short intervals of hypotension can lead to renal ischemia.

Also, if they clamped the aorta during surgery for any length of time then blood flow again to the renal beds was impaired.

Also, and i always go back to this when i'm looking at someone with 'renal failure'...their state prior to the procedure is very important.

Did they get dye for a ct scan? If so there's a big reason especially with diabetes.

what is the baseline. Remember creatinine is a product of muscle mass. The little old lady with a creatinine of 1.0 already has renal failure she just doesn't have the muscle to generate enough creatinine to reveal itself.

Renal failure is more concerning when the creat. goes from 0.8 or so to 1.2 or thereabout rather than those who started with a creat of 1.9 and and it goes to 2.3. the degree of renal failure is different in those two cases.

As a nurse your 5th VS should be urinary output. Do not wait till the end of the shift to see if your patient urinated. It's a huge thing and unfortunately the I and O is often delegated to a CNA who may not report that only 100 cc was made in an 8 hour period.'

Sorry for the rant...i spent hours on ARF and usually it is completely avoidable.