B4.038 - Interpreting Arterial Blood Gas Prework 3

Question 1

step 1 of diagnosing acid base issues

Answer 1

step 1 - what is pH (7.35-7.45)

Question 2

how do you differentiate if someones disorder is primarily respiratory or metabolic?

Answer 2

respiratory - high or low pCO2 (more than 40 or low) with compensatory bicarb changes

metabolic - changes in HCO3- primarily with compensatory pCO2

Question 3

how do you know if a respiratory disturbance is acute or chronic

Answer 3

acute - an increase in pCO2 shifts the equilibrium between CO2 and HCO3 to increase HCO3. This occurs almost immediately

chronic - the kidneys respond by retaining HCO3 this takes a few days to fully occur)

Question 4

what do COPD patients have as far as balance

Answer 4

high HCO3- to compensate for the acidosis they usually have from low ventilation

Question 5

describe acute respiratory alkalosis

Answer 5

decrease in pCO2 shifts the equilibrium between CO2 and pCO2 to decrease the HCO3- this occurs very quickly

Question 6

what is winters formula

Answer 6

PCO2 = 1.5 x HCO3 + 8

it tells you if the respiration is adquately compensating for metabolic alidocis

Question 7

if the actual measured pCO2 is much greater than whats expected according to Winters formula what does that mean

Answer 7

the respiratory system is not fully compensating for the metabolic acidosis and a respiratory acidosis is concurrently present

Question 8

in emphysema what is pCO2 like

Answer 8

usually elevated, if they have metabolic acidosis the body wants to blow oc CO2 but becaue of emphysema they will have metabolic acidosis and secondary respiratory bc of lack of compensatory ability

Question 9

when do you calculate anion gap

Answer 9

if there is metabolic acidosis

Question 10

what is the equation for anion gap

Answer 10

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

Question 11

what is a normal anion gap

Answer 11

12

Question 12

what is the electroneutrality principle

Answer 12

for every molecule of unmeasure anion present, one molecule of bicarbonate is lost

Question 13

if there is an anion gap metabolic acidosis and there are other metabolic derangements present what equation do you use to find corrected HCO3

Answer 13

Corrected HCO3 = measured CO3 + (anion gap - 12)

Question 14

what is a delta gap

Answer 14

corrected HCO3

Question 15

if corrected HCO3 is less than normal (22) what does that mean

Answer 15

There is an additional metabolic disorder present

Question 16

what does a correcte HCO3 over 26 mean

Answer 16

there is an additional metabolic alkalosis