Acid-Base Disorders Flashcards
PCO2
partial plasma for CO2
what values are found in an ABG?
pH, HCO3, PCO2
when do you do the Allen test?
prior to drawing blood
why do we order an ABG?
assess respiratory (ventilation) and metabolic (renal) and electrolyte homeostasis
- manage ventilator
- pre-op assessment
- acute/critical illness assessment
why do we use radial instead of femoral artery?
it is a cleaner site
what does the allen test accomplish?
identifies if the ulnar artery will compensate for the radial artery if you block it while taking the sample
-ensures patency
what kind of test tube will you use to get a blood gas?
green top (heparin)
how quickly should your blood gas sample get to the lab?
ASAP or place on ice
one or two sticks?
you may use lidocaine to numb the area prior to drawing blood from the RA
positive Allen test means
ulnar artery is not patent and you cannot use that hand (7-10 seconds return)
contraindications for RA
no palpable pulse cellulitis or open infection AV fistula severe coagulopathy positive Allen test
what are the potential complications of drawing a blood gas?
arterial occlusion
penetration of other important structures nearby
what is the normal pH of arterial blood?
7.4
what is the normal pH of venous blood and interstitial fluid
7.35 (has extra CO2 released from nearby tissues that makes it more acidic)
what is the normal pH of intracellular fluid
estimated to be between 6.0-7.4
what is considered acidosis?
<7.35
what is considered alkalosis?
> 7.45
what are the lower and upper limits of pH that support life?
6.8<8.0 (more than a few hours at the high and low end will end life)
where is Hydrogen found most?
intracellular (which makes cells more acidic)
what is the alkaline substance in the body?
HCO3