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Cards In This Set
| Front | Back |
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What are 3 clinical reasons for a (true) abnormal blood gas result?
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1. Patient is not getting enough O2 (airway blocked, COPD) 2. Patient is not getting rid of enough CO2
3. Patient has renal problems |
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How are blood gas results affected when there is a delay in sample processing (> 30 mins from time of collection)?
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Due to cellular respiration: pCO2 increases, pO2 decreases, pH decreases
Also potassium is increased due to continual leakage from the RBCs, and glucose is decreased due to glycolysis. |
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What is the ~ pO2 & pCO2 of atmospheric (room) air?
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PO2 = ~ 150 mmHg
pCO2 = ~ 1 mmHg |
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What is the pKa of the bicarbonate buffer system? What is the approximate pH when there is a 20:1 ratio of bicarb to H2CO3?
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PKa = 6.1
pH = 7.4 |
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What is the normal reference range for arterial pH? pO2? pCO2?
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PH 7.35 - 7.45
pO2 80 - 100 mmHg pCO2 35 - 45 mmHg |
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When the body undergoes an acidosis, how does the respiratory system try to compensate?
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Hyperventilates to decrease pCO2
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What is deoxyhemoglobin? How many molecules of O2 is hemoglobin capable of carrying?
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Hemoglobin that is not bound to O2.
Hg can carry up to 4 molecules of O2. |
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What is carboxyhemoglobin? Is the bond reversible?
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Hemoglobin bound to CO (carbon monoxide). Yes it is reversible, but very difficult! Hg prefers CO 200 x more than O2.
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What is methemoglobin (met-Hg)? Can it be reversed/"fixed"?
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Hemoglobin with oxidized iron Fe3+ (ferric); can't carry O2;
Can force reduce the Fe3+ iron into Fe2+ ferrous iron via methemoglobin reductase enzyme found in RBCs. |
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What is sulfhemoglobin? Can it be reversed?
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Hemoglobin bound to sulfur. Can NOT be reversed (irreversible bond); remains until the RBC finishes it's life cycle.
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Name some chemistry analytes that would be increased if there is a delay in centrifugation (>2 hr after collection)
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Potassium, LD, Phosphorus, Mg all will continue to leak out of RBCs.
Ammonia, creatinine, ALT, AST |
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Name some chemistry analytes that would be decreased if there is a delay in centrifugation.
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Glucose, ionized calcium, bicarb
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What is the formula to calculate RCF?
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RCF = 1.12 x r (mm) x (RPM/1000)^2
or RCF = 1.118 x 10^ -5 x radius (cm) x RPM^2 (from wiki) |
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What chemistry analytes are increased due to hemolysis?
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Potassium, LD, AST, ALT, IRON, AMMONIA*, Mg, Phosphorus, Protein
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What chemistry analyte is falsely elevated due to patient smoking before collection?
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Ammonia
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