Acid Base Balance 1

Module 1: Acid-Base Balance

Learning Outcomes:

  • Analyze respiratory acidosis and respiratory alkalosis.

  • Describe Acid-Base conditions and determine differences.

  • Identify causes and conditions associated with acid-base imbalances and how to correct these imbalances.

  • Compare risk factors and prevention of acid-base imbalances.

  • Identify clinical manifestations of acid-base imbalances.

  • Identify nursing interventions directed at maintaining acid-base balance.

  • Interpret Arterial Blood Gas (ABG) results.

  • Differentiate care of patients with respiratory acidosis and alkalosis across the lifespan.

Acid-Base Balance

  • pH of Arterial Blood: The normal pH range for arterial blood is between 7.35 and 7.45.

    • Acidic Conditions: pH < 7.35 (Acidosis)

    • Alkaline Conditions: pH > 7.45 (Alkalosis)

    • Survival pH Range: pH between 6.8 and 8.0 is critical for survival.

Analyzing Arterial Blood Gas Results

  • Normal Arterial Blood Gas Values:

    • pH: 7.35 - 7.45

    • PCO2 (Partial pressure of carbon dioxide): 35-45 mmHg

    • HCO3 (Bicarbonate): 22-26 mEq/L

    • Types of Imbalances:

    • Respiratory (related to lungs)

    • Metabolic (related to kidneys)

Respiratory Acidosis

  • Definition: Respiratory acidosis occurs in conditions that impair alveolar ventilation, leading to an increase in CO2 (hypercapnia) and a decrease in O2 (hypoxemia).

  • Characteristics:

    • pH < 7.35

    • Can be either acute or chronic.

  • Causes:

    • Hypoventilation

    • Respiratory depression (due to anesthesia or overdoses)

    • Airway obstruction

    • Alveolar capillary diffusion issues (e.g., pneumonia, COPD, ARDS, PE)

    • Retention of CO2 by lungs.

Clinical Manifestations of Respiratory Acidosis

  • Symptoms include:

    • Hypoventilation and hypoxia

    • Rapid, shallow respirations

    • Physiological Responses:

    • Decreased blood pressure

    • Skin/mucosa appearing pale to cyanotic

    • Headaches

    • Hyperkalemia, which may induce dysrhythmias

    • Mental status changes: drowsiness, dizziness, disorientation, muscle weakness, and hyperreflexia associated with increased potassium levels

Risk Factors for Respiratory Acidosis

  • Underlying respiratory conditions (e.g., COPD)

  • Use of opioids

  • Foreign body aspiration

  • Chest trauma

  • Neurological conditions such as multiple sclerosis and stroke.

Nursing Interventions for Respiratory Acidosis

  • Monitor for level of consciousness and signs of respiratory distress.

  • Implement proper positioning and ambulation to improve ventilation.

  • Utilize airway clearance techniques.

  • Prepare to administer respiratory treatments or oxygen therapy.

  • Hold respiratory depressants such as opioids and sedatives.

  • Administer antibiotics for any infections.

  • Monitor potassium levels carefully.

Pharmacologic Therapy for Respiratory Acidosis

  • Narcotic Overdose Treatment: Use opioid receptor antagonists, such as Naloxone.

  • Bronchodilators may be administered based on the patient's condition.

  • Antibiotics for treating respiratory infections.

Lifespan Considerations for Respiratory Acidosis

  • Infants and Children:

    • Increased risk factors include asthma, pneumonia, airway obstruction, head trauma, and poisoning.

    • Clinical manifestations are generally similar to those in adults.

  • Older Adults:

    • Risk factors may include COPD, chest wall abnormalities, and respiratory muscle weakness.

Nursing Process for Managing Respiratory Acidosis

  • Primary Focus: Improving breathing patterns and maintaining patent airway.

  • Thorough observations and patient interviews regarding current symptoms, health history, substance use, chronic conditions, and smoking history.

  • Complete physical examinations and assess mental status or level of consciousness, skin color, nail beds, vital signs, and pulse oximetry readings.

Diagnosis

  • Potential problems include:

    • Impaired airway clearance

    • Anxiety

    • Ineffective breathing pattern

    • Decreased cardiac output

    • Inadequate gas exchange.

  • Desired Outcomes May Include:

    • Maintain airway patency with an oxygen saturation greater than 92%.

    • Demonstrate effective breathing patterns.

    • Show improved mental status.

    • Normalize arterial blood gas (ABG) values.

Implementation of Nursing Interventions

  • Frequent assessment of:

    • Respiratory status and oxygen saturation levels

    • Level of consciousness

    • Administer oxygen therapy and execute airway clearance methods

    • Proper positioning and medication administration.

  • Evaluation: Assess improvement in mental status, including alertness and orientation.

    • Review trends in ABG and oxygen saturation (SpO₂) for signs of stabilization or improvement.

    • Confirm normalization of respiratory rate and pattern characteristics.

    • Ensure that the airway remains clear, and assess that the patient is breathing more easily and effectively.

Exemplar 1.D: Respiratory Alkalosis

  • Overview:

    • Respiratory alkalosis is caused by increased alveolar ventilation, often characterized by hyperventilation which leads to hypocapnia.

    • Defined by a pH > 7.45 and can also be either acute or chronic.

Pathophysiology and Etiology of Respiratory Alkalosis

  • Risk Factors Include:

    • Extreme anxiety disorders

    • Mechanical ventilation settings

    • Fever or sepsis

    • High altitude

    • Central nervous system disorders

    • Pain

    • Salicylate intoxication

    • Alcohol intoxication.

Clinical Manifestations of Respiratory Alkalosis

  • Neurological Symptoms: Lightheadedness, confusion, seizures, or even coma in severe cases.

  • Neuromuscular Symptoms: Tingling or numbness in the extremities (paresthesia), muscle cramps, and tetany.

  • Psychological Symptoms: Anxiety and restlessness.

Interventions for Respiratory Alkalosis

  • Provide emotional support by creating a calm environment for the patient.

  • Encourage appropriate breathing patterns, including voluntary breath-holding.

  • Promote rebreathing of exhaled carbon dioxide to correct hyperventilation.

  • Monitor electrolyte values, especially potassium and calcium.

  • Prepare to administer medications such as antianxiety agents as needed.

Lifespan Considerations for Respiratory Alkalosis

  • Older Adults:

    • More vulnerable to respiratory distress and chest pain.

    • They may require compensatory kidney excretion and should use pharmacotherapy cautiously.

    • Treatment outcomes depend on the nature of the illness and the promptness of diagnosis and management.