Block 2 Unit 4- Arterial Blood Gas Flashcards
What is an ABG?
An ABG is a blood test that measures the acid-base balance (pH) and the levels of oxygen (O2) and carbon dioxide (CO2) from an artery.
Newborn and Infants (0‐12 months old) will have the same normal values as adults. T or F?
False, Newborn and Infants (0‐12 months old) will have different normal values
What is the normal value for pH?
7.35-7.45
What is the normal value for PaO2?
80-100 mmHg
What is the normal value for PaCO2?
35-45mmHg
What is the normal value for HCO3?
22-26 mEq/L
What is the normal value for BE?
-2 to +2
What 2 body systems are responsible for controlling pH levels in the blood by regulating the acid-base balance?
respiratory and renal
How does the respiratory system maintains normal blood pH levels?
The respiratory system maintains normal blood pH levels by the regulation of carbondioxide (CO2‐) through exhalation.
When CO2‐ levels increase in the body, what does the respiratory system do to combat it and how?
the respiratory system changes breathing rates. By increasing or decreasing the respiratory rate, the lungs can regulate changes in blood pH levels within minutes.
How does the renal system assists with regulation of acid‐base balance?
The system assists with regulation of acid‐base balance through the excretion of hydrogenions (H+) in the urine and the return of bicarbonate (HCO3‐) to the blood.
What is Bicarbonate?
Bicarbonate is a base that acts as a buffer in the blood; CO2 and HCO3 work together to balance the pH.
How long does it take the body to make bicarbonate?
It can take several hours or even days for the renal system to regulate changes in blood pH levels.
If a patient’s pH is less than 7.35, the patient is in?
Acidosis
If the patient’s pH is more than 7.45, the patient is in?
alkalosis
Changes in the PaCO2 level reflect what?
lung function.
If the CO2 is high or low this means that the problem comes from a respiratory issue. If the CO2 is normal, then the problem is metabolic
the PaCO2 and pH are inversely related. T or F?
True
If the HCO3‐ is less than 22 mEq/L your patient
is in?
acidosis
If the HCO3‐ is greater than 26 mEq/L, then your patient is in?
alkalosis
What does ROME stand for?
stands for…
Respiratory Opposite, Metabolic, Equal.
If the HCO3- is normal, the PaCO2 value will be trending in the “opposite” direction of the pH‐ this will represent?
either respiratory acidosis/alkalosis
If the PaCO2 is normal, the HCO3- will be trending in the “equal” or same direction as the pH‐ this will represent?
either metabolic acidosis/alkalosis
The SaO2 is an important indicator of oxygenation. It is a direct measurement of oxygen that is attached to?
hemoglobin
If the PaO2 is less than __mmHg, or the SaO2 is less than__%, the patient has hypoxia
80, 95
the pH is not within or close to the normal ranges, this indicates?
a partial‐compensation
If the pH is back within normal ranges this indicates?
a full‐compensation
A non‐compensated or uncompensated abnormality usually represents what?
an acute change occurring in the body;
What is wrong with this patient?
They have Respiratory Acidosis
In respiratory acidosis, the patient will have what?
a below normal pH (acidosis) and high PCO2 (Retention by the lungs).
What are some of causes of respiratory acidosis?
• Hypoventilation
• Respiratory infection
• Severe airflow obstruction as in COPD or asthma
• Neuromuscular disorders
• Massive pulmonary edema
• Pneumothorax
• Central nervous depression
• Spinal cord injury
• Chest wall injury
During respiratory acidosis, what happens to the kidneys?
They will be drowsy and disoriented because kidneys don’t work properly and cannot remove potassium from the body or if you take certain medicines. Which can cause lethal dysrythmias
What happens with Metabolic Acidosis?
In metabolic acidosis, the patient is unable to get rid of acid or conserve base. The pH and HCO3‐ will both be below normal and trending the same way.
What are some causes of metabolic acidosis?
Renal failure
Diabetic ketoacidosis (DKA)
Lactic acidosis
Sepsis
Shock
Diarrhea
Drugs and toxins such as Ethylene glycol & Methanol
Metabolic acidosis causes hyperkalemia which results in what type of concentration that is elevated in relation to total body stores?
They will be hyperkalemia because, electroneutrality is maintained in part by the movement of intracellular potassium into the extracellular fluid.
Thus, metabolic acidosis results in a plasma potassium concentration that is elevated in relation to total body stores.
Why will a patient have decreased LOC with metabolic acidosis?
They will have a change in level of consciousness (LOC) because the patient becomes dehydrated from the loss of fluid from the causes: DKA, diarrhea, or shock
Why will a patient have decreased BP with metabolic acidosis?
They will be hypotensive because there is decreased cardiac output, arterial dilatation with hypotension, altered oxygen delivery to name a few causes.
What happens during respiratory alkalosis?
the patient will lose CO2 from the lungs through hyperventilation with deep, rapid respirations.
This will cause a high pH and a low PaCO2 in the patient.
What is wrong with this patient?
They have respiratory alkalosis
What’s wrong with this patient?
They have metabolic acidosis
What are some causes of respiratory alkalosis?
Causes of respiratory alkalosis include hyperventilation, pain, anxiety, early stages of pneumonia or pulmonary embolism (PE), hypoxia, brainstem injury, severe anemia, & excessive mechanical ventilation.
What is wrong with this patient?
They have metabolic alkalosis
What is metabolic alkalosis?
A decrease in acid or an increase in base will cause the metabolic alkalosis.
This will cause a high pH and a high HCO3‐ in the patient.
What are some specific Sx of metabolic alkalosis?
This patient will be restless because of decreased LOC, dizziness and irritability
This patient will be tachycardic because from dehydration from severe vomiting and diuretics
What are the Tx goals for Respiratory Acidosis?
improve ventilation through the use of bronchodilators, mechanical ventilation, administration of supplemental oxygen, suctioning
What are the Tx goals for Respiratory Alkalosis?
slowing the breathing rate, treating anxiety (may need an anxiolytic), pain relief, breathing into a paper bag allows a patient to re‐ breathe CO2. Mechanical ventilation correction should be done by a Provider or Respiratory Therapist
What are the Tx goals for Metabolic Acidosis?
treating diarrhea/vomiting with intravenous fluids or intravenous sodium bicarbonate, administer antibiotics for sepsis, and consider hemodialysis to reverse renal failure.
What are the Tx goals for Metabolic Alkalosis?
replacing electrolytes for imbalances and replace fluids to treat dehydration.
Lab values:
pH 7.56
paCo2 20
HCO3 20
respiratory alkalosis, partially compensated
Lab values:
pH 7.23
paCo2 37
HCO3 18
metabolic acidosis, uncompensated
Lab values:
pH 7.31
paCo2 34
HCO3 21
metabolic acidosis, partially compensated
Lab values:
pH 7.50
paCo2 32
HCO3 24
respiratory alkalosis, uncompensated
Lab values:
pH 7.46
paCo2 36
HCO3 32
metabolic alkalosis, uncompensated
Lab values:
pH 7.52
paCo2 48
HCO3 28
metabolic alkalosis, partially compensated
Lab values:
pH 7.25
paCo2 60
HCO3 27
respiratory acidosis partially compensated
Lab values:
pH 7.55
paCo2 47
HCO3 30
metabolic alkalosis, partially compensated
Lab values:
pH 7.20
paCo2 49
HCO3 25
respiratory acidosis, uncompensated
Lab values:
pH 7.30
paCo2 36
HCO3 16
metabolic acidosis, uncompensated
Lab values:
pH 7.41
paCo2 26
HCO3 17
respiratory alkalosis, fully compensated
Lab values:
pH 7.39
paCo2 48
HCO3 28
respiratory acidosis, fully compensated
Lab values:
pH 7.22
paCo2 49
HCO3 24
respiratory acidosis, uncompensated
Lab values:
pH 7.37
paCo2 33
HCO3 17
metabolic acidosis, fully compensated
Lab values:
pH 7.22
paCo2 49
HCO3 28
respiratory acidosis, partially compensated
Lab values:
pH 7.42
paCo2 32
HCO3 18
respiratory alkalosis, fully compensated
