Renal Physiology and AKI (Week 5): pH, BP, Diuretics, Clinical AKI Flashcards
are ones that are in gas form, and this means carbon dioxide, CO2.
Volatile acids
Can’t be expired. They are excreted by the kidneys.
Fixed acids
help blunt the change in pH that would occur from adding acid or alkali to a solution.
Buffers
What are an important intracellular buffer?
Proteins
What are an important extracellular buffer?
Bicarbonates
Proteins and bicarbonate, work instantly. They prevent
major swings in pH, but they do not get rid of the _________________
acid or base
What can lead to acidosis?
Increasing the hydrogen ion concentration
Where does bicarbonate reabsorption occur?
Proximal Tubules
(w/ little remaining for reabsorption in the loop of Henle and distal segments)
There are two main
buffers in the kidney:
phosphate and ammonia.
Why may cattle develop metabolic alkalosis with kidney failure?
Because cattle normally have renal bicarbonate excretion
Don’t treat with bicarb unless the pH is less than ______
7.1
the medical term used to describe having too much sodium in the blood
hypernatremic
The main ways the
kidney controls it is via ________ , which maintains renal perfusion and promotes correction of HYPOtension, and via pressure natriuriesis, which dumps sodium and water to correct
HYPERtension
RAAS
________________ is determined by cardiac output and total peripheral resistance, which is how tight the vessels are around the blood they contain.
Blood Pressure
_____________ is determined by heart rate and the stroke volume, which is the amount of blood pumped out of the heart with each heart beat
Cardiac Output
______________ is common with kidney disease
Hypertension
Equation for blood
pressure
BP = TPR x SV x HR
What are the most common causes of AKI?
ischemia and nephrotoxins
Seizures are not a common sign of ____________ , unless it is very severe AKI, or a puppy with renal dysplasia
kidney disease
Why don’t we usually measure GFR in patients with AKI?
Because GFR may be rapidly changing with AKI
(T/F) An acute diagnosis of kidney disease is not the same as acute kidney disease
True
Frequently the finding in a _________ patient is normal to slightly enlarged kidneys with no other distinguishing features
AKI
generally block the action of one of the transporters in the kidney, generally something related to decreasing sodium reabsorption.
Chemical Diuretics
alter the gradient for water reabsorption
Osmotic diuretics
is a loop diuretic because it works in the loop of Henle. Most of the side effects relate to the clinical effect – blocking reabsorption of potassium along with sodium, and excessive volume loss, but ototoxicity is another potential side effect seen at extremely high doses
furosemide
Drug that blocks aldosterone
Spironolactone
What does aldosterone do?
reabsorb sodium and secrete potassium
What happens if you block aldosterone?
You reabsorb less sodium, and if more sodium stays in the ultra-filtrate, more water stays, and you have a larger volume of urine
Potassium-sparing Diuretics:
Spironolactone, epleronone, amiloride, and triamterene
Unlike furosemide and thiazides, Spironolactone keeps the …
potassium levels from getting too low
Diuretics to increase urine output ___________ the outcome of AKI.
do NOT improve
is an osmotic diuretic that can be used if the patient hydration status is close to normal, but should be avoided with severe overhydration or dehydration.
Mannitol
The mean arterial pressure should be maintained above ________________ , or the systolic pressure above _________________
60 to 80 mm Hg, 80 to 100 mm Hg
In order to get rid of acid from the body, the kidneys must:
Both reabsorb filtered bicarbonate and secrete hydrogen ions
How do the kidneys help control blood pressure?
- Low blood volume stimulates renin release which stimulates angiotensin formation, which constricts blood vessels, increasing blood pressure
- An increase in blood volume increases glomerular filtration, which increases urine volume to decrease blood volume which decreases blood pressure
- Low blood volume stimulates renin release which stimulates angiotensin formation, which stimulates aldosterone which causes sodium retention which causes water retention and thus increases blood pressure
Administration of furosemide to an animal with AKI may:
Increase urine volume
