ABG's Flashcards
Assessment and Care of Patients with Acid-Base Imbalances
What is pH
balance of acids and bases in body fluids
What is the normal Arterial pH balance
7.35 to 7.45
What is the normal Venous pH balance
7.31 to 7.41
What is the normal pCO2
35-45 mmHg
What is the normal HCO3
22-26 mEq/L
What pH levels can be fatal
pH <6.9 or >7.8 usually fatal
Respiratory system more sensitive to which imbalance
acid-base changes; can begin compensating in seconds to minutes
Kidneys are more powerful in what?
result in rapid changes in ECF composition; fully triggered for imbalance of several hours to days
What are the types of Acid-Base Imbalances
Metabolic acidosis
Respiratory acidosis
Metabolic alkalosis
Respiratory alkalosis
Acid-Base Mnemonic—ROME
Respiratory
Opposite
Alkalosis ↑ pH ↓ PaCO2
Acidosis ↓ pH ↑ PaCO2
Metabolic
Equal
Acidosis ↓ pH ↓ HCO3
Alkalosis ↑ pH ↑ HCO3
Laboratory Assessment:
Metabolic Acidosis
pH <7.35
Bicarbonate <21 mEq/L
Pao2 normal
Paco2 normal or slightly decreased
Serum potassium high
Respiratory Acidosis
Respiratory function is impaired, causing problems with O2 and CO2
Retention of CO:
Respiratory depression
Inadequate chest expansion
Airway obstruction
Reduced alveolar-capillary diffusion
Hallmark of respiratory acidosis:
Decreased Pao2 with rising Paco2
Laboratory Assessment:
Respiratory Acidosis
pH <7.35
Pao2 low
Paco2 high
Serum bicarbonate variable
Serum potassium levels elevated (if acute acidosis)
Serum potassium levels normal or low (if renal compensation present
Acidosis: Patient-Centered Collaborative Care
History
CNS changes
Neuromuscular changes
↓ Muscle tone, deep tendon reflexes
Cardiovascular changes
Early: ↑ Heart rate, cardiac output changes
Worsening: Hyperkalemia; ↓ heart rate; T wave peaked and QRS widened; weak peripheral pulses; hypotension
Respiratory changes
Kussmaul respiration
Skin changes (metabolic and respiratory acidosis)
Warm, dry, and pink (vasodilation)
Psychosocial assessment
Interventions: Metabolic Acidosis
Hydration
Drug therapy
Insulin to treat DKA
Antidiarrheals
Bicarbonate (only with low serum level)
Interventions: Respiratory Acidosis
Focus is on improving ventilation and oxygenation, maintaining patent airway
Drug therapy
Bronchodilators
Anti-inflammatories
Mucolytics
Oxygen therapy
Pulmonary hygiene
Ventilation support
Prevention of complications
Metabolic Alkalosis
Base excess – Excessive intake bicarbonates, carbonates, acetates, citrates
Acid deficit – Prolonged vomiting, excess cortisol, hyperaldosteronism, thiazide diuretics, prolonged NG suction
Hallmark of base excess acidosis:
ABG result with ↑ pH and ↑ bicarbonate level with normal O2 and CO2 levels
Respiratory Alkalosis
Hyperventilation – Anxiety, fear, improper vent settings, stimulation of central respiratory center due to fever, CNS lesion, salicylates
Hallmark of respiratory alkalosis:
ABG result with ↑ pH coupled with low CO2 level
O2 and bicarbonate usually normal
Alkalosis: Patient-Centered Collaborative Care
Assessment (same for metabolic and respiratory alkalosis)
Hypocalcemia
Hypokalemia
CNS changes – Positive Chvostek’s and Trousseau’s signs
Neuromuscular changes – Tetany-twitching of facial muscles
Cardiovascular changes
Respiratory changes
Interventions: Alkalosis
Prevent further losses of hydrogen, potassium, calcium, chloride ions
Restore fluid balance
Monitor changes, provide safety
Modify or stop gastric suctioning, IV solutions with base, drugs that promote hydrogen ion excretion
