Arterial blood gases section 3

Question 1

respiratory acid base disorders are compensated by

Answer 1

metabolic mechanisms
ex. if you have respiratory acidosis, then your body will use the metabolic ability to lower bicarbonate level and bring levels back to normal.

Question 2

metabolic acid base disorders are compensated by

Answer 2

respiratory mechanisms
ex. if you have metabolic acidosis, then your body will use the respiratory ability to lower bicarbonate level and bring levels back to normal.

Question 3

compensation
respiratory
metabolic

Answer 3

Onset/full effect
30 mins/12-24 hours
6 - 12 hours/3-5 days
compensatory responses do not bring it all the way back to normal pH, but close

Question 4

In respiratory alkalosis or acidosis, its important to determine if patient has experienced this disorder on an

Answer 4

acute or chronic basis because the onset of the compensatory response. these respiratory disorders are using metabolic system to compensate so its going to take even more time to fully compensate.
if someone has had it for day 5/6/7, then you use respiratory acidosis chronic equation
but if someone is at day 1, we are using acute equation because we are just starting to manifest from that metabolic response.

Question 5

primary metabolic disorder: is actual Paco2 = expected paco2?

Answer 5

yes = simple acid base disorder
no
-actual PaCO2 > expected = concurrent respiratory acidosis
-actual PaCO2 < expected = concurrent respiratory alkalosis
SO a concurrent respiratory acidosis will increase PaCO2

Question 6

primary respiratory disorder: is actual HCO3- = expected HCO3-?

Answer 6

yes = simple acid base disorder
no
-HCO3- < expected = concurrent metabolic acidosis
-HCO3- > expected = concurrent metabolic alkalosis

Question 7

how to calculate expected in order to find out if the patient has mixed or simple?
7.25/28/209/14

Answer 7

40 - expected PaCO2 = 1.3 (24-14)
40 is the average of PaCO2 and 24 is the average for HCO3-. 14 is actual value of patient. =27. very close to 28, so not mixed, just primary metabolic acidosis.

Question 8

physiological electroneutrality

when bicarbonate is altered what is the consequence?

Answer 8

for amount of cationic charge you have, you should have equal anionic charge. cationic charge is primary represented as Na, K, and unmeasured cations. should be equal with Cl-, hco3-, and unmeasured anions.
when bicarbonate decreases, the chloride levels increase to maintain electric neutrality or the level of unmeasured anions increase

Question 9

the height of the bar

Answer 9

determines electroneutrality. height has to stay the same to remain electrically neutral.

Question 10

anion gap

Answer 10

measures unmeasured anions
[Na] - [cl-] - [hco3-]
normal anion gap is 8-12 mEq/L
ex. if its 10, the amount of chloride you have is increased bc you know hco3- has increase so you must have a compensatory increase somewhere in order to maintain electroneutrality

Question 11

unmeasured anions

Answer 11

albumin, p, organic anions

Question 12

unmeasured cations

Answer 12

k, ca, mg

Question 13

metabolic acidosis 2 anion gap graphs

Answer 13

-high anion gap metabolic acidosis
increase in unmeasured anions
-non-anion gap (hyperchloremic) metabolic acidosis
no increase in unmeasured anions, but Cl increases

Question 14

(patient with metabolic acidosis ONLY) for HIGH anion gap, calculate
if its equal to 1?

Answer 14

change in anion gap/ change in bicarbonate hco3-
if its equal to 1, they have moved to equal extents. that means however much the bicarbonate has decreased, the unmeasured anions have increased, so cl has remained unchanged.

Question 15

less than 1 anion gap

Answer 15

anion gap has changed less than your bicarbonate has changed. so cl must have changed a little bit. represents concurrent non anion gap (hyperchloremic) metabolic acidosis

Question 16

greater than 1 anion gap

Answer 16

anion gap has changed more than your bicarbonate has changed.
represents concurrent metabolic alkalosis.