Respiratory System and Oxygenation

• Oxygen is a clear, odorless gas, making up 21% of the air and crucial for living cells to function.
• Lack of oxygen can result in cell, tissue, and organism death.
• Cellular metabolism produces carbon dioxide, which the body must remove to maintain acid-base balance.
• Oxygen delivery and carbon dioxide removal require integrated hematologic, cardiovascular, and respiratory systems.

Key Definitions

• Oxygenation is the process of delivering oxygen to body tissues and cells.
• Respiration is the exchange of gas between an individual and the environment.
• Ventilation involves air movement in and out of the lungs.
• Diffusion is gas movement from an area of higher concentration to a lower one.

Physiology of the Respiratory System

• Respiration involves four components:
  • Ventilation (breathing): Air movement into and out of the lungs.
  • Alveolar-capillary gas exchange: Diffusion of oxygen and carbon dioxide between alveoli and pulmonary capillaries.
  • Transport: Oxygen and carbon dioxide transport between tissues and lungs.
  • Gas Exchange: Movement of oxygen and carbon dioxide between systemic capillaries and tissues.

Structure of the Respiratory System

• Structurally divided into the upper and lower respiratory systems.

Pulmonary Ventilation

• Ventilation occurs through breathing: inspiration (inhalation) and expiration (exhalation).
• Adequate ventilation depends on:
  • Clear airways
  • An intact central nervous system (CNS) and respiratory center
  • An intact thoracic cavity
  • Adequate pulmonary compliance and recoil.

Transport of Oxygen and Carbon Dioxide

• Oxygen is transported from the lungs to the tissues, while carbon dioxide is transported from tissues back to the lungs.
• Most oxygen (97%) combines with hemoglobin in red blood cells (RBCs), forming oxyhemoglobin.
• Factors affecting oxygen transport rate:
  • Cardiac output
  • Number of erythrocytes and blood hematocrit
  • Exercise

Respiratory Regulation

• Respiratory regulation uses neural and chemical controls to maintain oxygen, carbon dioxide, and hydrogen ion concentrations.
• The nervous system adjusts alveolar ventilation rate to maintain constant PO2 and PCO2.
• The respiratory center is located in the medulla oblongata and pons of the brain.

Factors Affecting Respiratory Function

• Age
• Environment
• Lifestyle
• Health status
• Medication
• Stress

Conditions Affecting the Airway

• Airway obstruction can occur in upper or lower respiratory passageways.
• Upper airway obstruction (nose, pharynx, or larynx) can be caused by:
  • Foreign objects like food
  • The tongue falling back into the oropharynx during unconsciousness
  • Secretions collecting in passageways

Breathing Patterns

• Eupnea: Normal, quiet, rhythmic, and effortless respiration.
• Tachypnea: Rapid respiration, associated with fever, metabolic acidosis, pain, and hypoxemia.
• Bradypnea: Abnormally slow respiration, seen with drugs like morphine, metabolic alkalosis, or increased intracranial pressure.
• Apnea: Absence of breathing.
• Hypoventilation: Inadequate alveolar ventilation.
• Kussmaul’s breathing: Hyperventilation due to metabolic acidosis, attempting to eliminate acid via CO2.
• Hyperventilation: Can occur due to stress or anxiety.

Irregular Breathing Rhythms

• Cheyne-Stokes respirations: Rhythmic waxing and waning of respirations with periods of apnea, commonly caused by chronic diseases, increased intracranial pressure, or drug overdose.
• Biot’s (cluster) respirations: Shallow breaths interrupted by apnea, seen in clients with CNS disorders.
• Orthopnea: Difficulty breathing unless sitting upright or standing.
• Dyspnea: Difficulty breathing or feeling short of breath (SOB).

Conditions Affecting Diffusion

• Impaired diffusion affects blood gas levels, especially oxygen.
• Hypoxemia: Reduced oxygen levels in the blood
• Hypoxia: Insufficient oxygen anywhere in the body.
• Cyanosis: Bluish discoloration of the skin, nail beds, and mucous membranes due to reduced hemoglobin-oxygen saturation.

Conditions Affecting Transport

• The cardiovascular system transports oxygen to tissues and carbon dioxide from cells to the lungs.
• Decreased cardiac output (e.g., congestive heart failure or hypovolemia) affects tissue oxygenation.

Clinical Manifestation of Hypoxia

• Rapid pulse
• Rapid, shallow respirations and dyspnea
• Restlessness or light-headedness
• Flaring of the nares
• Substernal or intercostal retractions
• Cyanosis

Nursing Management

• Assessment: Includes history, physical examination, and review of diagnostic data.

Nursing History

• Includes data about:
  • Current and past respiratory problems
  • Lifestyle
  • Cough, sputum, or pain
  • Medications for breathing

Physical Examination

• Inspection
• Palpation
• Percussion
• Auscultation
• Observe rate, depth, rhythm, and quality of respirations, noting the client’s position for breathing,inspect for variations in thorax shape.
• Barrel chest is frequently found with clients who have emphysema.

Diagnostic Studies

• Sputum specimens, throat cultures, visualization procedures
• Venous and arterial blood specimens
• Pulmonary function tests
• Measurement of arterial blood gases

Nursing Diagnosis

• Ineffective Airway Clearance related to inability to clear secretions or obstructions
• Ineffective Breathing Pattern related to inadequate ventilation
• Impaired Gas Exchange related to excess or deficit in oxygenation and/or carbon dioxide elimination
• Activity Intolerance related to insufficient energy for daily activities

Planning

• Maintain a patent airway
• Improve comfort and ease of breathing
• Maintain or improve pulmonary ventilation and oxygenation
• Improve the ability to participate in physical activities