1. PBL RESPIRATORY SYSTEM ARTERIAL BLOOD GASES DR M NAEEM AFZAL MBBS, MCPS, FCPS, DIP-DIABETES (UK) ASSISTANT PROFESSOR EAST MEDICAL WARD KING EDWARD MEDICAL UNIVERSITY/MAYO HOSPITAL, LAHORE

2. What we are going to learn today Application of ABGs in cardiorespiratory problems Understanding Hypoxia due to AV shunts Understanding Hypoxia due to Pulmonary edema

3. Pre-test Questionnaire

4. Why exchange is different for two gases? Physiology of respiratory membranes Pathological changes in respiratory membranes

5. Factors affecting alteration of gas exchange Blood flow Air flow Respiratory membrane

6. Case Scenario A middle aged gentleman who is hypertensive, diabetic and smoker presents in ER with rapidly worsening shortness of breath. His examination shows bibasilar crepitations indicative of extra fluid in alveoli of lungs.

7. Problem What will happen to gas exchange? What will be the pathophysiology behind impaired gas exchange? Can you give more examples of shunt?

8. What will happen to gas exchange? Decreased Why? Fluid in lungs alveoli will impair the gas exchange

9. What will happen to gas exchange? Both gases or one gas? Type 1 respiratory failure

10. What will be the pathophysiology behind impaired gas exchange? Blood will flow but it will not be oxygenated V/Q Ratio?

11. Can you give more examples of shunt?

12. 2 nd Case scenario An elderly lady who has been operated for hip joint replacement one week ago, suddenly develops sharp excruciating chest pain on right side of chest along with shortness of breath? Examination shows tachycardia, tachypnea, and mild cyanosis. All findings are indicative of pulmonary embolism.

13. Problems? What will happen to gas exchange? What will be pathophysiological mechanism of impaired gas exchange?

14. What will happen to gas exchange? Both gases or one gas? Type 1 respiratory failure

15. What will be pathophysiological mechanism of impaired gas exchange? Air will come but gases will not be exchanged V/Q ratio

16. Arterial Blood Gases Type 1 respiratory failure Effect on other gas Renal compensation

17. Post test Questionnaire Application of knowledge 2 different scenarios

18. Summarization Shunt Dead space Type 1 respiratory failure