RESPIRATORY ACID-BASE IMBALANCES
The body has the remarkable ability to maintain plasma pH within a narrow range of 7.35–7.45. It does so by means of chemical buffering mechanisms involving the lungs and kidneys. Although simple acid-base imbalances (e.g., respiratory acidosis) do occur, mixed acid-base imbalances are more common (e.g., the respiratory acidosis/metabolic acidosis that occurs with cardiac arrest).
RESPIRATORY ACIDOSIS (PRIMARY CARBONIC ACID EXCESS)
Respiratory acidosis (elevated PaCO2 level) is caused by hypoventilation with resultant excess carbonic acid (H2CO3). Acidosis can be due to/associated with primary defects in lung function or changes in normal respiratory pattern. The disorder may be acute or chronic.
Compensatory mechanisms include (1) an increased respiratory rate; (2) hemoglobin (Hb) buffering, forming bicarbonate ions and deoxygenated Hb; and (3) increased renal ammonia acid excretions with reabsorption of bicarbonate.
Acute respiratory acidosis: Associated with acute pulmonary edema, aspiration of foreign body, overdose of sedatives/barbiturate poisoning, smoke inhalation, acute laryngospasm, hemothorax/pneumothorax, atelectasis, adult respiratory distress syndrome (ARDS), anesthesia/surgery, mechanical ventilators, excessive CO2 intake (e.g., use of rebreathing mask, cerebral vascular accident [CVA] therapy), Pickwickian syndrome.
Chronic respiratory acidosis: Associated with emphysema, asthma, bronchiectasis; neuromuscular disorders (such as Guillain-Barré syndrome and myasthenia gravis); botulism; spinal cord injuries.
CARE SETTING
This condition does not occur in isolation, but rather is a complication of a broader health problem/disease or condition for which the severely compromised patient requires admission to a medical-surgical or subacute unit.
RELATED CONCERNS
Plans of care specific to predisposing factors/disease or medical condition, e.g.:
Cerebrovascular accident (CVA)/stroke
Chronic obstructive pulmonary disease (COPD) and asthma
Craniocerebral trauma (acute rehabilitative phase)
Eating disorders: obesity
Alcohol: acute withdrawal
Spinal cord injury (acute rehabilitative phase)
Surgical intervention
Ventilatory assistance (mechanical)
OTHER CONCERNS
Fluid and electrolyte imbalances
Metabolic acidosis
Metabolic alkalosis
Patient Assessment Database
Dependent on underlying cause. Findings vary widely.
ACTIVITY/REST
May report: Fatigue, mild to profound
May exhibit: Generalized weakness, ataxia/staggering, loss of coordination (chronic), to stupor
CIRCULATION
May exhibit: Low BP/hypotension with bounding pulses, pinkish color, warm skin (reflects vasodilation of severe acidosis)
Tachycardia, irregular pulse (other/various dysrhythmias)
Diaphoresis, pallor, and cyanosis (late stage)
FOOD/FLUID
May report: Nausea/vomiting
NEUROSENSORY
May report: Feeling of fullness in head (acute—associated with vasodilation)
Headache, dizziness, visual disturbances
May exhibit: Confusion, apprehension, agitation, restlessness, somnolence; coma (acute)
Tremors, decreased reflexes (severe)
RESPIRATION
May report: Shortness of breath; dyspnea with exertion
May exhibit: Respiratory rate dependent on underlying cause, i.e., decreased in respiratory center depression/ muscle paralysis; otherwise rate is rapid/shallow
Increased respiratory effort with nasal flaring/yawning, use of neck and upper body muscles
Decreased respiratory rate/hypoventilation (associated with decreased function of respiratory center as in head trauma, oversedation, general anesthesia, metabolic alkalosis)
Adventitious breath sounds (crackles, wheezes); stridor, crowing
TEACHING/LEARNING
Refer to specific plans of care reflecting individual predisposing/contributing factors.
Discharge plan
DRG projected mean length of inpatient stay: 4.9 days
May require assistance with changes in therapies for underlying disease process/condition
Refer to section at end of plan for postdischarge considerations.
DIAGNOSTIC STUDIES
ABGs: PaO2: Normal or may be low. Oxygen saturation (SaO2) decreased.
PaCO2: Increased, greater than 45 mm Hg (primary acidosis).
Bicarbonate (HCO3): Normal or increased, greater than 26 mEq/L (compensated/chronic stage).
Arterial pH: Decreased, less than 7.35.
Electrolytes: Serum potassium: Typically increased.
Serum chloride: Decreased.
Serum calcium: Increased.
Lactic acid: May be elevated.
Urinalysis: Urine pH decreased.
Other screening tests: As indicated by underlying illness/condition to determine underlying cause.
NURSING PRIORITIES
1. Achieve homeostasis.
2. Prevent/minimize complications.
3. Provide information about condition/prognosis and treatment needs as appropriate.
DISCHARGE GOALS
1. Physiological balance restored.
2. Free of complications.
3. Condition, prognosis, and treatment needs understood.
4. Plan in place to meet needs after discharge.
The body has the remarkable ability to maintain plasma pH within a narrow range of 7.35–7.45. It does so by means of chemical buffering mechanisms involving the lungs and kidneys. Although simple acid-base imbalances (e.g., respiratory acidosis) do occur, mixed acid-base imbalances are more common (e.g., the respiratory acidosis/metabolic acidosis that occurs with cardiac arrest).
RESPIRATORY ACIDOSIS (PRIMARY CARBONIC ACID EXCESS)
Respiratory acidosis (elevated PaCO2 level) is caused by hypoventilation with resultant excess carbonic acid (H2CO3). Acidosis can be due to/associated with primary defects in lung function or changes in normal respiratory pattern. The disorder may be acute or chronic.
Compensatory mechanisms include (1) an increased respiratory rate; (2) hemoglobin (Hb) buffering, forming bicarbonate ions and deoxygenated Hb; and (3) increased renal ammonia acid excretions with reabsorption of bicarbonate.
Acute respiratory acidosis: Associated with acute pulmonary edema, aspiration of foreign body, overdose of sedatives/barbiturate poisoning, smoke inhalation, acute laryngospasm, hemothorax/pneumothorax, atelectasis, adult respiratory distress syndrome (ARDS), anesthesia/surgery, mechanical ventilators, excessive CO2 intake (e.g., use of rebreathing mask, cerebral vascular accident [CVA] therapy), Pickwickian syndrome.
Chronic respiratory acidosis: Associated with emphysema, asthma, bronchiectasis; neuromuscular disorders (such as Guillain-Barré syndrome and myasthenia gravis); botulism; spinal cord injuries.
CARE SETTING
This condition does not occur in isolation, but rather is a complication of a broader health problem/disease or condition for which the severely compromised patient requires admission to a medical-surgical or subacute unit.
RELATED CONCERNS
Plans of care specific to predisposing factors/disease or medical condition, e.g.:
Cerebrovascular accident (CVA)/stroke
Chronic obstructive pulmonary disease (COPD) and asthma
Craniocerebral trauma (acute rehabilitative phase)
Eating disorders: obesity
Alcohol: acute withdrawal
Spinal cord injury (acute rehabilitative phase)
Surgical intervention
Ventilatory assistance (mechanical)
OTHER CONCERNS
Fluid and electrolyte imbalances
Metabolic acidosis
Metabolic alkalosis
Patient Assessment Database
Dependent on underlying cause. Findings vary widely.
ACTIVITY/REST
May report: Fatigue, mild to profound
May exhibit: Generalized weakness, ataxia/staggering, loss of coordination (chronic), to stupor
CIRCULATION
May exhibit: Low BP/hypotension with bounding pulses, pinkish color, warm skin (reflects vasodilation of severe acidosis)
Tachycardia, irregular pulse (other/various dysrhythmias)
Diaphoresis, pallor, and cyanosis (late stage)
FOOD/FLUID
May report: Nausea/vomiting
NEUROSENSORY
May report: Feeling of fullness in head (acute—associated with vasodilation)
Headache, dizziness, visual disturbances
May exhibit: Confusion, apprehension, agitation, restlessness, somnolence; coma (acute)
Tremors, decreased reflexes (severe)
RESPIRATION
May report: Shortness of breath; dyspnea with exertion
May exhibit: Respiratory rate dependent on underlying cause, i.e., decreased in respiratory center depression/ muscle paralysis; otherwise rate is rapid/shallow
Increased respiratory effort with nasal flaring/yawning, use of neck and upper body muscles
Decreased respiratory rate/hypoventilation (associated with decreased function of respiratory center as in head trauma, oversedation, general anesthesia, metabolic alkalosis)
Adventitious breath sounds (crackles, wheezes); stridor, crowing
TEACHING/LEARNING
Refer to specific plans of care reflecting individual predisposing/contributing factors.
Discharge plan
DRG projected mean length of inpatient stay: 4.9 days
May require assistance with changes in therapies for underlying disease process/condition
Refer to section at end of plan for postdischarge considerations.
DIAGNOSTIC STUDIES
ABGs: PaO2: Normal or may be low. Oxygen saturation (SaO2) decreased.
PaCO2: Increased, greater than 45 mm Hg (primary acidosis).
Bicarbonate (HCO3): Normal or increased, greater than 26 mEq/L (compensated/chronic stage).
Arterial pH: Decreased, less than 7.35.
Electrolytes: Serum potassium: Typically increased.
Serum chloride: Decreased.
Serum calcium: Increased.
Lactic acid: May be elevated.
Urinalysis: Urine pH decreased.
Other screening tests: As indicated by underlying illness/condition to determine underlying cause.
NURSING PRIORITIES
1. Achieve homeostasis.
2. Prevent/minimize complications.
3. Provide information about condition/prognosis and treatment needs as appropriate.
DISCHARGE GOALS
1. Physiological balance restored.
2. Free of complications.
3. Condition, prognosis, and treatment needs understood.
4. Plan in place to meet needs after discharge.
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