Med Surg: Exam 1- Introduction to ABGs (Arterial Blood Gases)

•are a series of tests used to measure the acidity (pH) and levels of oxygen (O2) and carbon dioxide (CO2) in the blood.

•These tests are crucial in assessing a patient's lung function and overall oxygenation status.

What are ABGs?

•1. pH: Measures the acidity or alkalinity of the blood.

•2. PaCO2: Partial pressure of carbon dioxide, indicates respiratory function.

•3. HCO3: Bicarbonate, indicates metabolic function.

•4. PaO2: Partial pressure of oxygen, indicates oxygenation status.

what are the 4 key components of ABGs?

•1. pH: 7.35 - 7.45

•2. PaCO2: 35 - 45 mmHg

•3. HCO3: 22 - 26 mEq/L

•4. PaO2: 80 - 100 mmHg

what are the normal lab values for an ABG?

A condition where the lungs can’t remove enough CO₂, causing blood pH to drop (<7.35, acidic).

What is respiratory acidosis?

Airway obstruction, drug overdose, pneumonia, ARDS.

What are the acute causes of respiratory acidosis?

COPD, neuromuscular disorders (e.g., Guillain-Barré), obesity hypoventilation.

What are the chronic causes of respiratory acidosis?

ABG: ↓ pH (<7.35), ↑ PaCO₂ (>45 mmHg); plus chest X-ray, pulmonary function tests, electrolytes.

How is respiratory acidosis diagnosed?

Improve ventilation (bronchodilators, oxygen, mechanical ventilation), treat underlying cause (e.g., antibiotics), monitor ABGs and electrolytes.

What is the treatment plan for respiratory acidosis?

Assess respiratory rate, ABGs, mental status, lung sounds; position for optimal ventilation, suction as needed, administer meds, monitor vitals.

What are key nursing interventions for respiratory acidosis?

Excessive breathing (hyperventilation) causes low CO₂, increasing blood pH (>7.45, alkaline).

What is respiratory alkalosis?

Pulmonary: hypoxemia, pneumonia, asthma, PE.
Non-pulmonary: anxiety, fever, pain, pregnancy, CNS disorders, high altitude, salicylate toxicity.

Causes of respiratory alkalosis?

ABG: ↑ pH (>7.45), ↓ PaCO₂ (<35 mmHg); electrolytes ↓ K⁺, ↓ Ca²⁺; ECG may show arrhythmias.

How is respiratory alkalosis diagnosed?

Treat underlying cause, encourage slow controlled breathing (e.g., paper bag if appropriate), adjust ventilator settings, correct electrolytes.

Treatment plan for respiratory alkalosis?

Assess: RR, ABGs, anxiety, neuro signs.
Diagnosis: ineffective breathing, anxiety, risk electrolyte imbalance.
Intervention: breathing coaching, relaxation, monitor vitals/labs.
Evaluation: stable ABGs, reduced symptoms, effective coping.

Nursing process for respiratory alkalosis?

Body accumulates too much acid or loses too much base, lowering blood pH (<7.35).

What is metabolic acidosis?

Increased acid: DKA, lactic acidosis.
Loss of bicarbonate: diarrhea, GI fistulas.
Decreased acid excretion: renal failure, toxins (methanol, ethylene glycol).

Causes of metabolic acidosis?

ABG: ↓ pH, ↓ HCO₃⁻ (<22 mEq/L); plus serum lactate, electrolytes, urinalysis, ECG for arrhythmias.

How is metabolic acidosis diagnosed?

Treat cause (e.g., insulin for DKA), give fluids, sodium bicarbonate if severe, monitor ABGs, electrolytes, cardiac rhythm.

Treatment plan for metabolic acidosis?

Assess Kussmaul respirations, confusion, hypotension; diagnose risk for decreased CO, impaired tissue perfusion; interventions: monitor vitals, meds/fluids, mental status; evaluate ABGs, vitals, alertness.

Nursing process for metabolic acidosis?

Excess base or loss of acid raises blood pH (>7.45).

What is metabolic alkalosis?

Acid loss: vomiting, NG suction.
Excess base: antacids, bicarbonate.
Other: diuretics, hypokalemia, Cushing’s syndrome.

Causes of metabolic alkalosis?

Monitor electrolytes (K⁺, Cl⁻), assess for signs of neuromuscular irritability (tetany, tingling), correct underlying cause, monitor ABGs and vitals.

Nursing considerations for metabolic alkalosis?