Acid-Base Balance
Body maintains balance through:
1. Buffer
2. Respiratory system
3. Renal system
Normal Arterial Blood Gases Values
pH - 7.35-7.45
PaCO2 - 35-45 mmHg
Bicarbonate - 22-26 mEq/L
PaO2 - 80-100 mmHg
SaO2 - >95%
Base excess - +/- 2
Respiratory Acidosis
Patho: increased CO2 retention from hypoventilation, compensatory response is an increase in bicarbonate
retention by the kidneys.
Causes:
● Respiratory muscle weakness
● Pulmonary edema
● viral respiratory infection; severe pneumonia
● inadequate chest expansion (COPD)
● broken ribs
● airway obstruction
● Atelectasis
● Opioids, sedative meds, and anxiolytics
● Mechanical hypoventilation
*carbonic acid excess when the person HYPOventilates (this leads to a buildup of CO2)
Assessment:
● Tachycardia, tachypnea
● Rapid shallow breathing
● Anxiety, restlessness, confusion (due to oxygen levels dropping), coma
● Decreased BP
● Ventricular fibrillation r/t hyperkalemia
● Warm, flushed skin
● Hypoventilation with hypoxia
Lab Findings:
● Decreased pH (less than 7.35pH)
● Increased PaCO2 (greater than 45mmHg)
● Bicarbonate normal if uncompensated (22-26 mEq/L) increased bicarbonate if compensated (greater
than 26mEq/L)
Nursing Interventions: Goal to improve ventilation
, ● Goal: improve ventilation
● Monitor for signs of respiratory distress
● Airway/O2
● Breathing
● Position: Fowler
● Clear mucous: turn, cough, and deep breathe
● Hydration
● Meds: bronchodilators; antibiotic
● Prepare for endotracheal intubation and mechanical ventilation if CO2 level > 50 mmHg
Respiratory Alkalosis
Patho: carbonic acid deficit occurs with HYPERventilation or an increase in respiratory rate or volume
Causes:
● Hyperventilation
● Hypoxemia from acute pulmonary disorders (pneumonia, pulmonary embolus)
● Liver failure
● Pain, anxiety, some CNS disorders
● Pulmonary fibrosis
● Exercise
● Fever causes increased metabolism, resulting in overstimulation of the respiratory system
Lab Findings:
● Increased pH (greater than 7.45pH)
● Decreased PaCO2 (less than 35mmHg)
● Bicarbonate normal - uncompensated; bicarbonate decreased - compensated
Clinical Manifestations:
● Dizziness, light-headedness, confusion, HA
● Tachycardia
● Dysrhythmias r/t hypokalemia from compensation
● NVD
● Epigastric pain
● Tetany, numbness, tingling
● Hyperreflexia, seizures
● Hyperventilation
Nursing Interventions:
Body maintains balance through:
1. Buffer
2. Respiratory system
3. Renal system
Normal Arterial Blood Gases Values
pH - 7.35-7.45
PaCO2 - 35-45 mmHg
Bicarbonate - 22-26 mEq/L
PaO2 - 80-100 mmHg
SaO2 - >95%
Base excess - +/- 2
Respiratory Acidosis
Patho: increased CO2 retention from hypoventilation, compensatory response is an increase in bicarbonate
retention by the kidneys.
Causes:
● Respiratory muscle weakness
● Pulmonary edema
● viral respiratory infection; severe pneumonia
● inadequate chest expansion (COPD)
● broken ribs
● airway obstruction
● Atelectasis
● Opioids, sedative meds, and anxiolytics
● Mechanical hypoventilation
*carbonic acid excess when the person HYPOventilates (this leads to a buildup of CO2)
Assessment:
● Tachycardia, tachypnea
● Rapid shallow breathing
● Anxiety, restlessness, confusion (due to oxygen levels dropping), coma
● Decreased BP
● Ventricular fibrillation r/t hyperkalemia
● Warm, flushed skin
● Hypoventilation with hypoxia
Lab Findings:
● Decreased pH (less than 7.35pH)
● Increased PaCO2 (greater than 45mmHg)
● Bicarbonate normal if uncompensated (22-26 mEq/L) increased bicarbonate if compensated (greater
than 26mEq/L)
Nursing Interventions: Goal to improve ventilation
, ● Goal: improve ventilation
● Monitor for signs of respiratory distress
● Airway/O2
● Breathing
● Position: Fowler
● Clear mucous: turn, cough, and deep breathe
● Hydration
● Meds: bronchodilators; antibiotic
● Prepare for endotracheal intubation and mechanical ventilation if CO2 level > 50 mmHg
Respiratory Alkalosis
Patho: carbonic acid deficit occurs with HYPERventilation or an increase in respiratory rate or volume
Causes:
● Hyperventilation
● Hypoxemia from acute pulmonary disorders (pneumonia, pulmonary embolus)
● Liver failure
● Pain, anxiety, some CNS disorders
● Pulmonary fibrosis
● Exercise
● Fever causes increased metabolism, resulting in overstimulation of the respiratory system
Lab Findings:
● Increased pH (greater than 7.45pH)
● Decreased PaCO2 (less than 35mmHg)
● Bicarbonate normal - uncompensated; bicarbonate decreased - compensated
Clinical Manifestations:
● Dizziness, light-headedness, confusion, HA
● Tachycardia
● Dysrhythmias r/t hypokalemia from compensation
● NVD
● Epigastric pain
● Tetany, numbness, tingling
● Hyperreflexia, seizures
● Hyperventilation
Nursing Interventions:
