Blood Gases Flashcards
Tube type used for blood gases.
Heparinized, plastic syringe.
What type of sample (anaerobic/aerobic) is needed for pH and blood gas studies?
Anaerobic.
How will CO2, pH, and O2 be affected by an opened sample?
↑ pH
↑ O2
↓ CO2 and pCO2
How will CO2, pH, and O2 be affected by the sample not being put on ice right away?
↑ CO2
↓ pH
↓ O2
In metabolic acidosis, the primary gas in deficit is..
HCO3.
What conditions could cause metabolic acidosis to occur?
DKA, renal disease, diarrhea, late salicylate poisoning.
In metabolic acidosis, what are the compensatory mechanisms used for the lungs and kidneys?
Primarily respiratory - Hyperventilation - ↓pCO2 Some renal - ↑ excretion of H - Reabsorption of HCO3
What are common lab findings for metabolic acidosis?
↑pH, HCO3, CO2, and pCO2; acidic urine.
In metabolic alkalosis, there is an excess of ___.
Bicarbonate (HCO3).
Metabolic alkalosis is seen in what conditions?
Vomiting, K depletion, diuretic therapy, and Cushing’s Syndrome.
What types of respiratory compensatory mechanisms are used for a patient in metabolic alkalosis?
Primarily respiratory: hypoventilation, ↑ retention of CO2.
What types of renal compensatory mechanisms are used for a patient in metabolic alkalosis?
Some renal: ↓ excretion of H; ↑ excretion of HCO3.
What are common lab findings for a patient in metabolic alkalosis?
↑ pH, HCO3, CO2, and pCO2.
In respiratory acidosis, patients primarily have excess ___.
CO2.
Respiratory acidosis is seen in what conditions?
Emphysema, pneumonia, and rebreathing air (paper bag).
What renal compensatory mechanisms are used for a patient in respiratory acidosis?
↑ H excretion; HCO3 reabsorption.
What are common lab findings in patients with respiratory acidosis?
↓ pH, and ↑ HCO3, CO2, and pCO2.
For a patient in respiratory alkalosis, the primary deficit is ___.
CO2.
Respiratory alkalosis is commonly seen in what conditions?
Hyperventilation and early salicylate poisoning.
What renal compensatory mechanisms are used for a patient in respiratory alkalosis?
↓ H excretion.
What are common lab findings in patients with respiratory alkalosis?
↑ pH and HCO3; ↓ pCO2 and CO2.
If pCO2 is opposite of pH, it is a likely indication of…
respiratory condition.
If HCO3 and pH are going in the same direction, it is likely an indication of…
metabolic condition.
When a patient has known alkalosis/acidosis and the pH returns to normal, what is likely the cause?
Full compensation occured.
If main compensatory mechanism kicked in, but pH is still out of normal range, what likely occurred?
Partial compensation occured.
Primary respiratory dysfunction results in change in ___ (seesaw); main compensation is HCO3 (metabolic).
pCO2.
Primary metabolic dysfunction results in change in ___ (swing); main compensation is pCO2 (respiratory).
HCO3.
Define Base Excess/Deficit.
Defined as the amount (dose) of acid/base needed to return pH to normal.
What two blood gasses are used to determine the Base Excess/Deficit calculation?
pH and pCO2.
A positive base excess (↑pH) is an indication of…
Metabolic alkalosis.
A negative base excess (↓pH) is an indication of…
metabolic acidosis.
pH reference range.
7.35 - 7.45.
pCO2 reference range.
35 - 45 mmHg.
HCO3 reference range.
22 - 26 mmol/L.
pO2 reference range.
85 - 105 mmHg.
