Cross Species - Blood Gas Analysis Flashcards
what is the difference in information obtained from running a blood gas on arterial vs venous blood?
arterial - information on pulmonary function through pO2 & pCO2, venous - info on acid-base status
pO2 is only evaluated on what type of blood gas samples?
arterial sample
how should a sample be collected for running a blood gas sample?
collected into a heparinized syringe & immediately capped to prevent alterations from air exposure - run immediately
how does pCO2 & HCO3 determine pH derangements?
pCO2 determines respiratory derangements in pH & HCO3 determines metabolic derangements in pH
what is the normal canine/feline range for pH on a blood gas?
7.35-7.45
what is the normal equine range for pH on a blood gas?
7.36-7.43
what is the normal bovine range for pH on a blood gas?
7.36-7.46
what is the normal canine/feline range for pCO2 on a blood gas?
35-45
what is the normal equine range for pCO2 on a blood gas?
36-46
what is the normal bovine range for pCO2 on a blood gas?
35-44
what is the normal canine/feline range for base excess on a blood gas?
plus or minus 6
what is the normal canine/feline range for arterial pO2 on a blood gas?
95
what is the normal equine range for HCO3 on a blood gas?
24-31
what is the normal equine range for base excess on a blood gas?
plus or minus 4
what is the normal equine range for arterial pO2 on a blood gas?
94
what is the normal bovine range for arterial pO2 on a blood gas?
92
what is the normal bovine range for HCO3 on a blood gas?
22-30
what is the normal bovine range for base excess on a blood gas?
negative 1.4 to nine
what does a blood gas test measure?
pH, pCO2, HCO3, & pO2 only on arterial samples
what is the first step in evaluating blood gas results? what does an increased pH mean? a decreased pH?
determine acid-base disturbance by looking at pH - pH under 7.35 is acidemia & over 7.45 is alkalemia
after assessing pH on a blood gas, what do you do next?
determine if the primary disturbance is metabolic or respiratory by looking at pCO2 & HCO3
what values indicate a respiratory acidosis on blood gas?
pH under 7.35, pCO2 greater than 45
what values indicate a respiratory alkalosis on blood gas?
pH greater than 7.45, pCO2 less than 35
what values indicate a metabolic acidosis on blood gas?
pH less than 7.35, HCO3 less than 20
what values indicate a metabolic alkalosis on blood gas?
pH greater than 7.45, HCO3 greater than 24 & BE greater than 6
how is an anion gap calculated?
(Na + K) - (HCO3 + Cl) - it is the difference between unmeasured cations & unmeasured anions
what does an increased anion gap indicate?
increased unmeasured anions (lactic acid, ketoacids, uremic acids)
why is it important to remember that the body NEVER overcompensates when evaluating a blood gas result?
a change in pH must be due to the PRIMARY acid-base disturbance
what is an example of respiratory compensation in a patient with metabolic acidosis?
decreased pCO2
T/F: degree of compensation provides information about the chronicity of a primary problem
TRUE
what is the timeline for respiratory compensation for metabolic disturbances?
rapid, minutes to hours - can take 24 hours for complete compensation
what is the timeline for metabolic compensation for respiratory disturbances?
takes longer - complete compensation takes 3-5 days
what clues should make you think of a mixed disturbance?
pH doesn’t move in expected direction for primary disturbance
what is a mixed acid-base disturbance?
when two abnormalities cause a change in blood pH
what are the top causes of metabolic acidosis?
increased lactate (canine GDV, hypoperfusion, equine colic, endotoxemia, & rumen overload), DKA in dogs & cats, & acute or chronic renal failure
what are the top causes of metabolic alkalosis?
vomiting (gastric outflow tract or duodenal obstruction causing loss of HCl in small animals), sweating/myopathy in horses, & displaced abomasum/torsion in cattle
what are the top causes of respiratory acidosis?
upper airway obstruction, hypoventilation (CNS disease), & neuromuscular disease
what are the top causes of respiratory alkalosis?
hypoxemia, pulmonary disease, excessive panting/hyperventilation, & canine hyperadrenocorticism
what are the most common acid-base disturbances?
metabolic acidosis & respiratory alkalosis
glucose measured off of abdominal effusion indicates septic effusion with what values?
serum glucose more than 20 mg/dL higher than abdominal effusion suggests septic effusion
what cage side analyzer is used for blood glucose in cats & dogs that is more accurate that human analyzers?
alphatrak blood glucose meter
what does increased lactate indicated?
tissue hypoxia due to decreased oxygen availability (cardiac disease, hypoperfusion, & shock), & non-hypoxemic causes such as GDV, neoplasia, sepsis, & DKA
what is the normal value for blood lactate?
less than 2mmol
T/F: a significant increase in lactate is associated with being a negative prognostic indicator
TRUE
if abdominal effusion lactate is higher than blood lactate, what should you be concerned with?
septic etiology
what is serum amyloid a? how is it used in equine medicine?
acute phase protein that increases rapidly with significant inflammation with a short half life that makes it useful for monitoring for infectious diseases & response to treatment
when are increases in cardiac troponin levels seen in horses?
myocarditis, sepsis, rattlesnake envenomation, & toxins
what does an increase in cardiac troponin indicate?
myocardial injury - short half life & very sensitive
what cage side analyzer is used to measure glucose in horses?
human glucometers or alphatrak
what is the CMT test used for in cattle?
used to assess somatic cells in milk from individual cows
what is a normal CMT result?
75% WBC (neutrophils most common) & 25% epithelial cells
healthy cows have less than how many somatic cells in their milk?
should be under 100,000
T/F: SCC increase in cows with mastitis & is useful to watch when diagnosing a cow with subclinical mastitis
TRUE
what is BHB in cows? what samples do you measure it off of?
beta-hydroxybutyrate - measures ketones in milk, urine, or blood
what is the normal canine/feline range for HCO3 on a blood gas?
20-24
