Types of Hypoxia Lecture Notes

Definition of Hypoxia

• Hypoxia: Inadequate oxygen delivery to tissue cells.
• Key organs affected include the brain and heart.

Identifying Stages of Hypoxia

Early Stages

• Mnemonic: RAT
  • R: Restlessness
  • A: Anxiety
  • T: Tachycardia (heart rate > 100 beats per minute)
  • T: Tachypnea (accelerated respiration)

Late Stages

• Mnemonic: BEDC
  • B: Bradycardia (heart rate < 60 beats per minute)
  • E: Extreme restlessness
  • D: Dyspnea (shortness of breath)
  • C: Cyanosis (bluish skin cast indicating inadequate oxygen)

Types of Hypoxia

1. Hypoxic Hypoxia

• Also known as Hypoxemic Hypoxia.
• Causes:
  • High altitudes: Reduced oxygen pressure in the atmosphere.
  • Pulmonary diseases: Such as chronic obstructive pulmonary disease (COPD), asthma.
  • Ventilation-perfusion mismatch: Altered ventilation or perfusion.
  • Pneumothorax: Air in pleural space compressing lungs.

2. Ischemic (Stagnant) Hypoxia

• Cause: Reduced blood flow to tissues
• Conditions:
  • Atherosclerosis: Occlusion of blood vessels.
  • Congestive heart failure: Reduced cardiac output.

3. Anemic Hypoxia

• Cause: Low or abnormal hemoglobin or red blood cells.
• Types of anemia:
  • Aplastic
  • Hemolytic
  • Iron deficiency
  • Sickle cell

4. Histotoxic Hypoxia

• Cause: Cells unable to use oxygen despite normal delivery.
• Commonly due to cyanide poisoning which inhibits mitochondrial cytochrome oxidase.

Treatment of Hypoxia

Hypoxic Hypoxia

• Supplemental oxygen: Treat with caution in COPD patients.

Ischemic Hypoxia

• Thrombolytic drugs: Tissue plasminogen activator (TPA), warfarin, or surgical intervention.
• Congestive Heart Failure: Use digoxin and supplemental oxygen.

Anemic Hypoxia

• Blood transfusions: Depending on anemia type.
• Supplemental oxygen: Increases dissolved oxygen.

Histotoxic Hypoxia

• Cyanide poisoning treatment: Hydroxocobalamin, sodium thiosulfate.

Carbon Monoxide Poisoning

• High-pressure oxygen: Use hyperbaric oxygen chambers to displace carbon monoxide from hemoglobin.

Conclusion

• Understanding different types of hypoxia is crucial for proper diagnosis and treatment.
• Early recognition of signs is critical to prevent long-term damage to vital organs like the brain and heart.

Note: Be cautious with oxygen therapy in patients with lung diseases to avoid respiratory arrest.