Fl 3

Definition: Acid–Base Balance refers to the regulation of hydrogen ion (H⁺) concentration in the body fluids.
pH Measurement:
  - pH Scale:
    - Low pH → Acidic
    - High pH → Alkaline (Basic)
Normal Arterial Blood pH: 7.35 – 7.45
- pH < 7.35 = Acidosis - pH > 7.45 = Alkalosis
Normal Survival Range: 6.8 – 7.8
- pH values outside this range can be fatal.

Fluid | Approximate pH | Nature
  - Gastric juice: 1 – 3 (Strongly acidic)
  - Urine: ~6 (Slightly acidic)
  - Arterial blood: 7.35 – 7.45 (Slightly alkaline)
  - Venous blood: ~7.37 (Slightly more acidic than arterial)
  - Cerebrospinal fluid: ~7.32 (Slightly acidic)
  - Pancreatic fluid: 7.8 – 8.0 (Alkaline)

Buffer Systems (First Line of Defense)
   - Response Time: Seconds (fastest)
   - Function: Maintain pH by binding or releasing H⁺ ions, acting like sponges.
   - Main Buffers:
     - Bicarbonate–Carbonic acid buffer system
     - Phosphate buffer system
     - Protein buffer system (e.g., Albumin, Globulins)
     - Hemoglobin buffer (binds H⁺ in red blood cells)
   - When pH ↓ (acidic): Buffers bind excess H⁺
   - When pH ↑ (alkaline): Buffers release H⁺
Respiratory System (Second Line of Defense)
   - Response Time: Minutes
   - Mechanism: Regulates carbon dioxide (CO₂), which acts as an acid.
     - CO₂ ↑ → pH ↓ (acidosis)
     - CO₂ ↓ → pH ↑ (alkalosis)
   - CO₂ removal: via exhalation
   - Respiratory Compensation:
     - If acidotic: Increase respiratory rate/depth (hyperventilation) → blows off CO₂
     - If alkalotic: Slow breathing → retains CO₂
   - Controlled by: respiratory center in the brainstem.
Renal System (Third Line of Defense)
   - Response Time: Hours to Days (slowest)
   - Mechanism: Kidneys regulate H⁺ and HCO₃⁻.
     - When acidic: Excrete H⁺; retain HCO₃⁻
     - When alkaline: Retain H⁺; excrete HCO₃⁻
   - Provides: Long-term acid–base balance.

Two main types: Acidosis & Alkalosis
  - Each type is classified as either:
    - Respiratory (due to CO₂ imbalance)
    - Metabolic (due to HCO₃⁻ imbalance)
  - Onset:
    - Acute (sudden)
    - Chronic (develops over time)

Definition: Decrease in bicarbonate (HCO₃⁻) or accumulation of acid.
Causes:
  - Overproduction of acid:
    - Diabetic ketoacidosis (DKA)
    - Starvation/Malnutrition → fat breakdown → ketones
    - Lactic acidosis
  - Loss of base (HCO₃⁻):
    - Severe diarrhea (loss of lower GI fluids)
    - Renal failure (inability to excrete acids)
ABGs:
  - pH ↓ (< 7.35)
  - HCO₃⁻ ↓ (< 22 mEq/L)
  - CO₂ ↓ (if lungs compensate via hyperventilation)
Compensation:
- Lungs increase breathing rate → blow off CO₂ (Kussmaul respirations)
Signs & Symptoms:
  - Weakness, drowsiness, disorientation, confusion
  - Warm, dry skin
  - Nausea, vomiting
  - Deep, rapid breathing (Kussmaul’s respirations)
  - Hyperkalemia (K⁺ shifts out of cells)
  - Hypotension, dysrhythmias
  - Severe cases → coma
Nursing Interventions:
  - Monitor ABGs, electrolytes, EKG
  - Monitor for K⁺ elevation
  - Ensure airway, administer O₂ as needed
  - Treat underlying cause:
    - DKA → insulin & fluids
    - Renal failure → dialysis
    - Diarrhea → fluid replacement
  - Administer Sodium Bicarbonate if prescribed

Definition: Retention of excess CO₂ due to inadequate ventilation.
Causes:
  - Hypoventilation from:
    - COPD
    - Pneumonia, atelectasis
    - Airway obstruction
    - Respiratory depression (narcotics, anesthesia, head trauma)
    - Over-sedation
ABGs:
- pH ↓ (< 7.35) - PaCO₂ ↑ (> 45 mmHg)
- HCO₃⁻ ↑ with renal compensation (if chronic)
Signs & Symptoms:
  - Hypoventilation, shallow breathing
  - Confusion, lethargy, headache, drowsiness
  - Weakness, blurred vision
  - Hyperkalemia
  - Tachycardia, dysrhythmias
  - Hypoxia, cyanosis
  - Severe cases → coma
Nursing Interventions:
  - Assess airway and breathing
  - Reposition → Semi- or High-Fowler’s
  - Encourage deep breathing & coughing
  - Administer O₂ therapy
  - Use bronchodilators as ordered
  - Monitor ABGs, K⁺ levels, respiratory rate
  - If due to narcotic overdose: Administer Narcan (naloxone)
  - Assist with ventilation support if needed
Potential Nursing Diagnoses:
  - Ineffective Airway Clearance
  - Impaired Gas Exchange
  - Decreased Cardiac Output
  - Risk for Injury (CNS depression)

Definition: Increase in HCO₃⁻ or decrease in acids.
Causes:
  - Loss of acid:
    - Vomiting, gastric suctioning
  - Excess base intake:
    - Antacids (e.g., Alka-Seltzer, baking soda)
    - Excess bicarbonate therapy
  - Hypokalemia: Diuretic use or burns (K⁺ loss)
ABGs:
  - pH ↑ (> 7.45)
  - HCO₃⁻ ↑ (> 26 mEq/L)
  - CO₂ ↑ (respiratory compensation with possible hypoventilation)
Signs & Symptoms:
  - Irritability, confusion, dizziness
  - Hypertonic muscles, tetany, seizures
  - Dysrhythmias (hypokalemia-related)
  - Shallow breathing; possible apnea
Nursing Interventions:
  - Assess respiratory pattern & LOC
  - Correct electrolyte imbalance (replace K⁺, Cl⁻)
  - Stop gastric suctioning if excessive
  - Administer IV fluids (Normal Saline)
  - Monitor ECG, ABGs, serum electrolytes
  - Treat cause (e.g., hold antacids, correct vomiting)

Definition: Excessive excretion of CO₂ due to hyperventilation.
Causes:
  - Anxiety, fear, pain
  - Fever, infection
  - Hypoxia
  - Over-ventilation (mechanical ventilation)
  - CNS disease
ABGs:
  - pH ↑ (> 7.45)
  - CO₂ ↓ (< 35 mmHg)
  - HCO₃⁻ ↓ (renal compensation if chronic)
Signs & Symptoms:
  - Rapid respirations (hyperventilation)
  - Lightheadedness, dizziness
  - Paresthesia (tingling of fingers, toes)
  - Tinnitus (ringing in ears)
  - Numbness, blurred vision
  - Nausea, dry mouth
  - Anxiety, confusion
Nursing Interventions:
  - Encourage slow, controlled breathing
    - Example: guide breathing with eye contact or use a paper bag for rebreathing
  - Reduce anxiety; provide calm environment
  - Monitor O₂ saturation and ABGs
  - Administer O₂ if hypoxic
  - Monitor electrolytes, especially K⁺, Ca²⁺
  - Adjust ventilator settings if mechanically ventilated
  - Allow rest periods, semi-Fowler’s position
Potential Nursing Diagnoses:
  - Ineffective Breathing Pattern
  - Risk for Impaired Gas Exchange
  - Fluid Volume Deficit

Condition | pH | PaCO₂ | HCO₃⁻ | Main Cause
  - Metabolic Acidosis | ↓ | ↓ or Normal | ↓ | DKA, diarrhea
  - Respiratory Acidosis | ↓ | ↑ | Normal or ↑ | COPD, hypoventilation
  - Metabolic Alkalosis | ↑ | ↑ or Normal | ↑ | Vomiting, antacids
  - Respiratory Alkalosis | ↑ | ↓ | Normal or ↓ | Hyperventilation

Assess airway, breathing, circulation
Monitor ABG values, electrolytes, and neurological changes
Identify & correct underlying cause
Provide O₂ support, fluids, or medications as indicated
Ensure patient safety: confusion, weakness → fall precautions
Education about medication effects, breathing techniques, and diet (if relevant)