Lecture on Blood Gases and Arterial Blood Gas Analysis

Introduction

• Presenter: Armando Huran
• Platform: Biology and Medicine videos
• Topics: Blood gases, oxygen, and carbon dioxide concentrations in the lungs, blood, and tissues.

Partial Pressure of Gases

Atmospheric Gases

• Oxygen Partial Pressure: ~160 mm Hg
• Carbon Dioxide Partial Pressure: ~0.3 mm Hg

Inspiration and Expiration

• Inspiration:
  • Oxygen: ~120 mm Hg
  • Carbon Dioxide: ~27 mm Hg
• Expiration:
  • We don't use all inhaled oxygen.
  • Only a small amount of carbon dioxide is produced.

Role of Plants

• Plants use carbon dioxide to produce oxygen through photosynthesis.

Gas Exchange in the Lungs

Alveoli and Blood Flow

• Alveoli: Terminal respiratory tract structures.
• Pulmonary Arteries: Carry deoxygenated blood to alveoli.
• Pulmonary Veins: Transport reoxygenated blood back to the heart.

Detailed Gas Exchange Process

• In the Alveoli:
  • Oxygen moves from alveoli to blood.
  • Carbon dioxide moves from blood to alveoli.
• Partial Pressures in Alveoli:
  • Oxygen: ~100 mm Hg
  • Carbon Dioxide: ~40 mm Hg

Pulmonary Artery and Vein Details

• Pulmonary Artery:
  • Oxygen Partial Pressure: ~40 mm Hg
  • Carbon Dioxide Partial Pressure: ~46 mm Hg
• Pulmonary Vein:
  • Oxygen Partial Pressure: ~100 mm Hg
  • Carbon Dioxide Partial Pressure: ~40 mm Hg

Systemic Circulation

• Systemic Arteries:
  • Carry oxygenated blood to tissues.
  • Oxygen Partial Pressure: ~100 mm Hg
  • Carbon Dioxide Partial Pressure: ~40 mm Hg

Tissues

• Tissue Gas Exchange:
  • Oxygen Partial Pressure: <40 mm Hg
  • Carbon Dioxide Partial Pressure: >45 mm Hg

Arterial and Venous Blood Gas Analysis

Arterial Blood Gas (ABG)

• Measures:
  • pH: 7.35 - 7.45
  • Oxygen Partial Pressure: 80 - 100 mm Hg
  • Carbon Dioxide Partial Pressure: 35 - 45 mm Hg
  • Bicarbonate (HCO3-): 22 - 26 mEq/L
• Indications:
  • Acidosis or alkalosis.
  • Respiratory vs. metabolic issues.
  • Hemoglobin saturation: ~98%

Venous Blood Gas Analysis

• Measures:
  • pH: 7.38 - 7.43
  • Oxygen Partial Pressure: 35 - 40 mm Hg
  • Carbon Dioxide Partial Pressure: 41 - 52 mm Hg
  • Bicarbonate: 24 - 28 mEq/L
• Hemoglobin Saturation: ~75%

Conclusion

• Cycle of Blood Gases: Oxygen is used and carbon dioxide is produced by tissues; blood returns to the heart and lungs for reoxygenation.
• Importance of Plants: Utilize exhaled carbon dioxide and release oxygen.
• End Note: Emphasis on understanding blood gases and arterial blood gas analysis.

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• Video conclusion: Thank you for watching.