Blood Gas and Acid Base Flashcards
Why do you not want a venous sample for blood gas?
does not give direct measurement of arterial oxygenation
How do you properly collect a sample for blood-gas?
use a heparinized syringe and fill it completely to prevent diffusion of gases into air space at the top of the tube
How do you store a sample collected for blood-gas?
store at room temp. for up to 30 mins. before changes in acid-base will be seen
changes in PO2 will occur in 12 mins.
if analysis cannot be performed immediately, place sample in a 4 degree water bath for no longer than 3 hrs
At physiologic pH of ____ 95% of potential CO2 gas is in the form of _______.
At physiologic pH of 7.4, 95% of potential CO2 gas is in the form of bicarbonate.
When analyzing HCO3 and PCO2 for Acid-Base eval., which refers to metabolic changes and which refers to respiratory changes?
HCO3- : metabolic
PCO2 : respiratory
Compensatory changes are in response to primary acid-base changes. Primary acid-base changes go with/against the direction of pH.
Primary acid-base changes go WITH the direction of pH.
What is Base Excess/Base Deficit?
Metabolic non-respiratory component that reflects acid-base regulating ability of the kidneys (HCO3-) and the blood (hemoglobin) buffer system.
Base Excess =
Alkalosis
Base Deficit =
Acidosis
Metabolic Compensatory Mechanisms…for each 1mEq/L change in HCO3-, you expect…
0.7mmHg change in pCO2 in the same direction
Acute Respiratory Acidosis..for each 1mmHg change in pCO2, you expect…
0.15mEq/L change in HCO3-
Chronic Respiratory Acidosis…for each 1mmHg change in pCO2, you expect…
0.35mEq/L change in HCO3-
Acute Respiratory alkalosis…for each 1mmHg change in pCO2, you expect..
0.25mEq/L change in HCO3-
Chronic Respiratory alkalosis…for each 1mmHg change in pCO2, you expect…
0.55mEq/L change in HCO3-
What does blood gas measure?
pH pO2 pCO2 HCO3- O2 Sat.
