State whether this will cause acidosis or alkalosis:
1. Pulmonary edema
2. sepsis
3. severe diarrhea
4. vomiting
5. Hypoxia
6. salicylate OD
7. chest trauma
1. acid
2. acid
3. acid
4. base
5. base
6. acid
7. acid
What value of pCO2 is considered high?
>45
If pt. is in respiratory acidosis, what will the kidneys retain to compensate?
HCO3
What kind of breathing will you assess for with respiratory acidosis?
Hypoventilation:
- depth of ventilation
- restlessness, disorientation
- hypoxemia
T or F: in chronic respiratory acidosis, when a PCO2 >50, you should not give too much O2.
true: the patient is hypoxic, and it is their major stimulus for ventilation. Unless the person is in a emergent situation, giving too much O2 will stop the respiratory drive
What will pCO2 be in respiratory alkalosis? Is the cause hypo or hyperventilation?
<35mm Hg
Hyperventilation
In respiratory alkalosis, will the kidneys excrete or retain HCO3?
excrete
Lightheadedness, anxiety, restlessness, can all lead to resp. alkalosis or acidosis?
alkalosis
In metabolic acidosis, what will the HCO3 be? will it be high or low?
Low: <22-26
DKA, shock, ESRD can all cause...
Metabolic acidosis
What will you assess for with metabolic acidosis?
Breathing?
LOC?
K+?
Cardiac?
Rapid breathing
Drowsy and disorientated
Hyperkalemia
Dysrhythmia
NaHCO3 may be given for this:
C.
Will HCO3 be high or low with metabolic alkalosis? what will the values be?
High: >26
Severe vomiting, gastric suctioning, high-dose diuretic can all cause what?
Metabolic alkalosis
In metabolic alkalosis, will you assess for hypo or hyperkalemia?
Hypo
What is the easiest way to identify the primary cause of acid-base imbalance?
Look at which value (CO2 or HCO3) is most abnormal
What imbalance is this?
pH: 7.33
PaCO2: 67
PaO2: 47
HCO3: 37
pH is low
PaCO2 is high
HCO3 is high
Respiratory acidosis, partially compensated
By using the ROME (Respiratory Opposite Metabolic Equal) mnemonic, the respiratory component (PaCO2) is going in the opposite direction as the pH—thus, the patient has respiratory acidosis. Because the HCO3 is elevated, the patient is partially compensating.
What imbalance is this?
pH: 7.18
PacO2: 38
PaO2: 70
HCO3: 15
pH is low
PaCO is normal (35-45)
HCO3 is low (22-26)
Metabolic acidosis
The metabolic component is going the same direction as the pH.
The CO2 is normal, so there is no compensation.
If the response of an abnormal acid-base brings pH into the 7.35 or 7.45 range, the disorder is said to be...
compensated
What imbalance is this?
pH: 7.6
PaCO2: 30
PaO2: 60
HCO3: 22
pH is high
CO2 is low
O2 is low
HCO3 is normal
Respiratory alkalosis
the respiratory component is going the opposite direction as the pH.
The HCO3 is normal so there is no compensation
What imbalance is this?
pH: 7.58
CO2: 35
O2: 75
HCO3: 50
pH is high
CO2 is normal
O2 is low
HCO3 is high
Metabolic component is going the same direction as the pH
The CO2 is normal, showing no compensation
What imbalance is this?
pH 7.28
CO2: 28
O2: 70
HCO3: 18
pH is low
CO2 low
O2 low
HCO3 low
Metabolic acidosis, partially compensated
the metabolic component is going the same direction as the pH, thus metabolic acidosis
Because CO2 is also low, but the pH is not yet back to normal, there is partial compensation
pH 7.2
CO2: 58
O2: 59
HCO3: 24
pH is low
CO2 is high
O2 is low
HCO3 is normal
Pt. has uncompensated respiratory acidosis with hypoxemia.
tx: treating any underlying respiratory infections, bronchodilator, corticosteroid, hydration, breathing exercises, O2, and mechanical ventilation if RR deteriorates
pH: 7.39
CO2: 38
PO2: 44
HCO3: 24
pH normal
CO2 normal
O2 low
HCO3
Hypoxemic respiratory failure. ALL ABGs are normal except PaO2.
tx:
- O2, mobilizations of secretions
- positive-pressure ventilations via endo intubation if necessary
- IV fluids and meds if necessary
pH 7.2
PaCO2: 28
PaO2: 81
HCO3: 18
pH low
CO2: low
O2 normal
HCO3 low
decreased pH and HCO3 indicates metabolic acidosis with compensation.
Most common cause is DKA, which is treated with insulin
In case of starvation, carbs are provided
If d/t renal failure, dialysis may be used
pH: 7.57
PaCO2: 46
PO2: 87
HCO3: 38
pH high
CO2 slightly high
O2 normal
CO3 high
pH and HCO3 are elevated showing metabolic alkalosis
slightly elevated CO2 shows some compensation.
causes: severe vomiting or excessive gastric suctioning, duiretic therapy, low K, excessive intake of sodium bicarbonate
Tx: K+ supplement for low K+, d/c diuretics if cause, treat vomiting
A patient with an acid-base imbalance has an altered potassium level. The nurse recognizes that the potassium level is altered because
a.Potassium is returned to extracellular fluid when metabolic acidosis is corrected.
b.Hyperkalemia causes an alkalosis that results in potassium being shifted into the cells.
c.Acidosis causes hydrogen ions in the blood to be exchanged for potassium from the cells.
d.In alkalosis, potassium is shifted into extracellular fluid to bind excessive bicarbonate.
Answer: c
Rationale: Changes in pH (hydrogen ion concentration) will affect potassium balance. In acidosis, hydrogen ions accumulate in the intracellular fluid (ICF), and potassium shifts out of the cell to the extracellular fluid to maintain a balance of cations across the cell membrane. In alkalosis, ICF levels of hydrogen diminish, and potassium shifts into the cell. If a deficit of H+ occurs in the extracellular fluid, potassium will shift into the cell. Acidosis is associated with hyperkalemia, and alkalosis is associated with hypokalemia.
A patient has the following ABG results: pH 7.48, PaO2 86 mm Hg, PaCO2 44 mm Hg, HCO3 29 mEq/L. When assessing the patient, the nurse would expect the patient to have
4
a.Muscle cramping
b.Warm, flushed skin
c.Respiratory rate of 36
d.Blood pressure of 94/52
Answer: a
Rationale: The patient is experiencing metabolic alkalosis (elevated pH and elevated HCO3). Clinical manifestations of metabolic alkalosis include hypertonic muscles and cramping and reduced respiratory rate. Hypotension and warm, flushed skin may occur with respiratory acidosis.