nursing outcome
Acid-Base Balances
Staff Education
Awesome Student
Why is it important?
The balance between and acids and bases in the body is essential the the function of the human body.
A slight change in the acids or bases can be life threatening.
A patient could be respiratory acidosis, respiratory alkalosis, metabolic acidosis, or metabolic alkalosis.
The kidneys and lungs work together to help correct these imbalances.
Let's look at the normal lab values and symptoms of each…
Lab Values
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
PaO2 – 70 – 100 mmHg
SaO2 – 93 – 98%
HCO3- - 22 – 26 mmol/L
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Compensation
Fully Compensated – If the pH is normal
Partially Compensated – If all three lab values are abnormal
Uncompensated – if PaCO2 or HCO3 is normal and the other is abnormal
Respiratory Alkalosis
Symptoms:
Hyperventilation
Tachycardia
Hypokalemia
Decrease or normal BP
Numbness & tingling of extremities
Hyper reflexes & muscle cramping
Seizures
Increase anxiety & irritably
PH:
PaCO2:
HCO3-: Normal
Causes:
Hyperventilation
(anxiety, PE, fear)
Mechanical Ventilation
Respiratory Acidosis
Symptoms:
Hypoventilation – hypoxia
Rapids, shallow respirations
Decrease BP
Headache
Hyperkalmia
Dysrhythmias ( increase K+)
Drowsiness, dizziness, disorientation
Muscle weakness, hyperreflexia
PH:
PaCO2:
HCO3-: Normal
Causes:
Respiratory depression
Airway obstruction
Decrease alveolar capillary
Metabolic Alkalosis
Symptoms:
Restlessness followed by lethargy
Dysrhythmias (tachycadia)
Compensatory hypocentilation
Confusion (decrease LOC, dizzy, irritable)
Nausea, vomiting, diarrhea
Tremors, muscle cramps, tingling of fingers and toes
hypokalmia
PH:
PaCO2: Normal
HCO3-:
Causes:
Sever vomiting
Excessive GI suctioning
Diuretics
Excessive NaHCO3
Metabolic Acidosis
Symptoms:
Headache
Decrease BP
Hyperkalemia
Muscle twitching
Warm, flushed skin
Nausea, vomiting
Decreased muscle tone & reflexes
Kussmaul respirations
PH:
PaCO2: Normal
HCO3-:
Causes:
Increase H+ production
Decrease H+ elimination
Decrease HCO3 production
Increase HCO3 elimination
Dehydration, kidney failure, aspirin poisoning
Let’s look at the table (tic tac toe method)
| Acid | Normal | Base | |
| pH | < 7.35 | 7.35 – 7.45 | > 7.45 |
| pCO2 | > 45 | 35 - 45 | < 35 |
| HCO3- | < 22 | 22 - 26 | > 26 |
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Let’s practice!
A person was admitted in a coma. Analysis of the arterial blood gave the following values: PCO2 16 mm Hg, HCO3- 5 mmol/L and pH 7.1. What is the underlying acid-base disorder?
| Acid | Normal | Base |
| pH | ||
| HCO3- |
PCO2
Metabolic Acidosis – partially compensated
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
HCO3- - 22 – 26 mmol/L
10
Practice question
2. In a man undergoing surgery, it was necessary to aspirate the content of the upper gastrointestinal tract. After surgery, the following values were obtained from an arterial blood sample: pH 7.55, PCO2 52 mm Hg and HCO3 40 mmol/L. What is the underlying disorder?
| Acid | Normal | Base |
| pH | ||
| PCO2 | HCO3 |
Metabolic Alkalosis – partially compensated
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
HCO3- - 22 – 26 mmol/L
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Practice question
3. A student is nervous for a big exam and is breathing rapidly, what do you expect..
| Acid | Normal | Base |
**Do you remember the symptoms of each acid-base imbalances?
Respiratory Alkalosis
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
HCO3- - 22 – 26 mmol/L
Think stress what can lead to anxiety… hyperventilation
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Practice question
4. A patient’s arterial blood gas results are pH 7.48, PaCO2 38, HCO3 30. What acid-base imbalances are they presenting with
| Acid | Normal | Base |
Metabolic Alkalosis – partially compensated
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
HCO3- - 22 – 26 mmol/L
pH – base
paCO2 – base
HCO3 - base
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Practice question
5. A patient in the ED requires arterial blood gases to be drawn. Results come back as pH 7.31, PaCO2 50 mmHg, HCO3 22. What is the patient's acid-base imbalance and the compensation that defines this.
| Acid | Normal | Base |
Respiratory Acidosis, Uncompensated
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
HCO3- - 22 – 26 mmol/L
pH – acid
Hco3 – normal
Pacos - acid
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Practice question
6. ABG results come back on a patient you are caring for. pH 7.47, PaCO2 48 mmHg, HCO3 30. What is the patients compensation and acid-base imbalance?
| Acid | Normal | Base |
Metabolic alkalosis, compensated
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
HCO3- - 22 – 26 mmol/L
Ph – base
Paco2 – acid
Hco3 - base
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Can you remember the normal Values?
PH – 7.35 - 7.45
PaCO2 – 35 – 45 mmHg
PaO2 – 70 – 100 mmHg
SaO2 – 93 – 98%
HCO3- - 22 – 26 mmol/L
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PH –
PaCO2 –
PaO2 –
SaO2 –
HCO3-
Try this one on your own...
You the nurse are caring for a patient on the medical surgical unit. Arterial blood gases are order and received. The results come back as; pH 7.52, PCO2 24, PO2 85, and HCO3 24. What is acid – base imbalance is your patient experiencing?
Respiratory Alkalosis – uncompensated
Ph – base
Pco2 – base
Hco3 – normal
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Refrences
15.5 Acid-Base Balance – Nursing Fundamentals (pressbooks.pub)
Microsoft Word - Some Multiple Choice Questions and their key answers.docx (ksu.edu.sa)