23. Compensating for Respiratory and Metabolic Disturbances

Question 1

Two rules for compensation?

Answer 1

Compensation will never get me back exactly to normal

compensation must be made by other system

Question 2

If there a respiratory acidosis, how would you compensate?

Answer 2

Use kidneys (metabolic) to release HCO3 to bring down concentration of H+ so the pH will increase

Question 3

Glomerulus filters plasma for raw materials, then goes to proximal convoluted tubule where bulk operations in nephron occurs. Nephron takes back what it needs (glucose, proteins, etc). What is the next step?

Answer 3

The loop of Henle: concentrates interstitium, and lastly, the distal convoluted tubule and collecting duct make final adjustments/tuning to blood (ex absorb more sodium or water) *** acid base balancing occurs here for respiratory problems!!!

Question 4

Why is the distal convoluted tubule and collecting duct important for respiratory acid/alkalosis?

Answer 4

Cells here are able to secrete HCO3 or H+ as conditions demand

Question 5

If acidotic the DCT/CD cells will do what?

Answer 5

Move H+ ion to urine and take HCO3 and move it back to the blood, compensating for respiratory acidosis (plasma HCO3 levels will increase)

Question 6

If respiratory alkalosis the DCT/CD cells will do what?

Answer 6

HCO3 will go to the urine and the H+ will go to the blood, so the HCO3 plasma levels will be lower and the pH will become more acidic

Question 7

Is the problem is acute, there will be no compensation, if the problem is chronic, ?

Answer 7

There will be compensation

Question 8

What is the equation for acute respiratory acidosis to calculate the expected [HCO3]?

Answer 8

Expected [HCO3] = 24 + ((PaCO2-40)/10)

Question 9

What is the equation for chronic respiratory acidosis to calculate the expected HCO3 that will be compensating?

Answer 9

Expected [HCO3] = 24 + 4x((PaCO2-40)/10)

Question 10

What is the equation for acute respiratory alkalosis to calculate the expected HCO3 (will decrease)?

Answer 10

Expected HCO3 = 24 - 2((40 - PaCO2)/10)

Question 11

What is the equation for CHRONIC respiratory alkalosis to calculate the expected HCO3?

Answer 11

HCO3= 24- 5((40-PaCO2)/10)

Question 12

Peripheral chemoreceptors are sensitive to H+ which is being altered by ?

Answer 12

the metabolic disturbance, so peripheral are major players

Question 13

If there is an increase of H+ in the blood, the peripheral chemoreceptors will do what?

Answer 13

Increase ventilation to blow off more CO2 and reduce the PaCO2 and bring up pH

(opposite for when there is less H+)

Question 14

If I have metabolic alkalosis, there will be less activation of the chemorecptors and?

Answer 14

a decrease in ventilation to retain CO2, increasing H+, decreasing pH

Question 15

What is the equation for metabolic acidosis to calculate expected PaCO2?

Answer 15

(1.5[HCO3]+8) +/- 2

if between the certain range, the determine the compensation is adequate

Question 16

What is the equation for metabolic alkalosis to calculate expected change PaCO2 to determine if respiratory compensation is adequate?

Answer 16

(0.5 to 1.0) x changeHCO3

if between this range, compensation is adequate

Question 17

Why do we ask if compensation is adequate? (2)

Answer 17

1. respiratory response will be quick and occur before the condition can be chronic
2. Resp system can only influence only a small part of total HCO3, so it never gets the pHa as close to normal as might be expected (switched)

Question 18

What are some causes of chage in HCO3?

Answer 18

Renal problems
GI tract secretes lots of HCO3 and H+, so vomitting and diarrhea
too much tums

Question 19

The anion gap equation is base on the rule that positive and negatively charged anions balance themselves out. What is the equation?

Answer 19

Anion gap= [Na+] - ([Cl-]+[HCO3-])

Question 20

From results of anion gap: if acid is made that is not measured by tests, the acid will ?

Answer 20

consumed HCO3 because of the HCO3 role as a buffer

Question 21

What is the normal anion gap?

Answer 21

equal to or less than 12

Question 22

An elevated anion gap means?

Answer 22

There are unmeasured chemicals presents

MUDPILES
methanol
uremia
diabetic ketoacidosis
paraldehyde
isoniazid/iron
lactic acidosis
ethylene glycol
salicylates (aspirin)

Question 23

Osmolarity of blood can be measured how?

Remember normal osmolarity is 290mOsmoles/L

Answer 23

Osmolarity = (2xserumNa) + (BUN/2.8) + (glucose/18)