1. Dyspnea, Hypoxemia & Respiratory Failure 2012 Pulmonary Medicine Introductory Course 4 th year Workshop Dr. Samir Nusair, MD Dr. Nissim Arish, MD

2. Definition: Dyspnea is an abnormally uncomfortable awareness of breathing ATS definition: Subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity. The experience derives from interactions among multiple physiological, psychological, social, and environmental factors and may induce secondary physiological and behavioral responses 2012

3. Differential Diagnosis of Dyspnea Pulmonary veins Pulmonary arteries Y HEART LUNGS 2012

4. Approach to the Patient with Dyspnea History Physical Examination Diagnostic Testing –chest x-ray –ECG, echocardiography –pulmonary function tests –pulse oximetry, arterial blood gases 2012

5. SatO 2 vs. PaO 2 SatO 2 –reflects the % of Hgb which binds O 2 PaO 2 –reflects the driving pressure for oxygen in blood => Both factors combined determine oxygen content (תכולה)in blood 2012

6. Hypoxia vs. Hypoxemia: Hypoxia: the reduction of oxygen availability in tissues Hypoxemia: arterial oxygen tension (PaO 2 ) < 60mmHg, or arterial oxygen saturation (SaO 2 ) < 90% 2012

8. Hypoxemia: Mechanisms Extrapulmonary: Low Inspired O 2 (high altitude) Hypoventilation (kyphoscoliosis, sedation) Pulmonary: Ventilation Perfusion Mismatch –Shunt (pulmonary A-V fistula) –Diffusion Impairment (ILD, pulm vascular dis) 2012

9. Arterial Blood Gases Normal Values PO 2 75-100 mmHg PCO 2 35-45 mmHg 2012

10. Arterial Blood Gases Normal Values PO 2 75-100 mmHg PCO 2 35-45 mmHg PO 2 can be expected to change depending on: Ambient conditions Alveolar ventilation, reflected by the PCO 2 ! 2012

11. Alveolar-Arterial Oxygen Gradient A-a gradient = P A O 2 - P a O 2 A – Alveolar a – arterial 2012

12. Alveolar-Arterial Oxygen Gradient A-a gradient = P A O 2 - P a O 2 A – Alveolar a – arterial A-a gradient is a measure of oxygen transfer at the alveolar- capillary level 2012

13. Alveolar Gas Equation A-a gradient = P A O 2 - P a O 2 A – Alveolar a – arterial 2012

14. Alveolar Gas Equation A-a gradient = P A O 2 - P a O 2 P A O 2 = F i O 2 x (P B – P H 2 O ) – P a CO 2 /R A – Alveolar a – arterial F I O 2 – Fractional oxygen content in inspired air P B - Barometric pressure PH 2 O – Water vapor pressure R – Respiratory quotient 2012 # P a CO 2 /R reflects O 2 removal from alveoli

15. P A O 2 = F i O 2 x (P B – P H 2 O ) – P a CO 2 /R A – Alveolar a – arterial F I O 2 – Fractional oxygen content in inspired air P B - Barometric pressure PH 2 O – Water vapor pressure R – Respiratory quotient Alveolar Gas Equation 0.21700470.8 2012

16. Alveolar Gas Equation P A O 2 = 137 – P a CO 2 /0.8 A-a gradient = 137 – P a CO 2 /0.8 - P a O 2 Assumptions: 1.Room air (F i O 2 = 0.21 ) 2.Altitude of Jerusalem (P B = 700) 3.Normal renal function (R = 0.8) 4.At rest (R = 0.8) 2012

17. A-a Gradient Upper limit of normal A-a gradient = 4 + ¼ age 2012

18. Case #1 28 yr. old male, found lying in the street, brought in by ambulance –PO 2 65 mmHg –PCO 2 49 mmHg –Sat O 2 92% What is the A-a gradient? 2012

19. Case #1 28 yr. old male, found lying in the street, brought in by ambulance –PO 2 65 mmHg –PCO 2 49 mmHg –Sat O 2 92% –A-a O 2 10 mmHg (predicted = 11) 2012

20. Case #1 28 yr. old male, found lying in the street, brought in by ambulance –PO 2 65 mmHg –PCO 2 49 mmHg –Sat O 2 92% –A-a O 2 10 mmHg (expected = 11) Pin-point pupils. Needle-marks on arm. Diagnosis: heroin overdose Treated with naloxone – excellent response 2012

21. Case #2 60 yr. old male, sudden onset of dyspnea 48h after hip replacement surgery –PO 2 72 mmHg –PCO 2 30 mmHg –Sat O 2 94% What is the A-a gradient? 2012

22. Case #2 60 yr. old male, sudden onset of dyspnea 48h after hip replacement surgery –PO 2 72 mmHg –PCO 2 30 mmHg –Sat O 2 94% –A-a O 2 27.5 mmHg (predicted=19) 2012

23. Case #2 60 yr. old male, sudden onset of dyspnea 48h after hip replacement surgery –PO 2 72 mmHg –PCO 2 30 mmHg –Sat O 2 94% –A-a O 2 27.5 mmHg (predicted=19) CT Pulmonary Angiogram: multiple pulmonary emboli 2012

24. –PO 2 72 mmHg –PCO 2 30 mmHg –Sat O 2 94% –A-a O 2 27.5 (high) –PO 2 65 mmHg –PCO 2 49 mmHg –Sat O 2 92% –A-a O 2 10 (normal) Pulmonary Emboli Morphine Overdose Extra-pulmonary disorder:Pulmonary disorder: Case #1 Case #2 2012

25. Is hypoxemia a result of parenchymal or extraparenchymal lung disease? A means of follow-up Alveolar-Arterial Oxygen Gradient: Application 2012

26. PO 2, PCO 2 A-a gradientInterpretation Normal “Normal” or Abnormal AbnormalPulmonary Abnormality AbnormalNormalExtra- pulmonary Abnormality Alveolar-Arterial Oxygen Gradient: Interpretation 2012

27. Alveolar-Arterial Oxygen Gradient: Interpretation Causes of Increased Alveolar-Arterial Oxygen Difference Increased right-to-left shunt Anatomic Intrapulmonary Increased ventilation-perfusion mismatch Impaired diffusion Increased inspired partial pressure of oxygen Decreased mixed venous partial pressure of oxygen Shift of oxyhemoglobin dissociation curve 2012

28. A-a Gradient F i O 2 must be known accurately to calculate A-a gradient correctly! Use appropriate P B R (respiratory quotient) increased in renal failure, exercise 2012

29. Diagnostic Procedures in Pulmonology: Fiberoptic bronchoscopy Pleurocentesis Closed Pleural Biopsy 2012

30. Fiberoptic Bronchoscopy 2012

31. Fiberoptic Bronchoscopy: Diagnostic Inspection of the bronchial tree –Ostia of sub-segmental bronchi Bronchoalveolar lavage Endobronchial biopsy –Forceps –Brush Transbronchial biopsy –Forceps (lung parenchyma) –Needle (lymph nodes) 2012

37. Bronchoalveolar Lavage (BAL) BAL serves for alveolar sampling Procedure: –Bronchoscope is wedged at a distal point in the bronchial tree –Saline is instilled through the bronchoscope –Fluid is collected for analysis 2012

38. BAL fluid analysis Differential cell count (normal>85% macrophages) Pathogens / cytological signs of infection Malignant cells Foreign Bodies (Asbestos, Silica) 2012

39. Diffuse Infiltrates in Immunocompromised Host

40. Chest 2000 2012

41. Fiberoptic Bronchoscopy: Therapeutic Bronchial toilet Restoration of airway patency –Laser photo-coagulation / resection –Electro-cautery –Stent deployment –Brachy-radiotherapy –Foreign body removal 2012

42. Endobronchial brachytherapy 2012

43. Laser photoresection 2012

44. Endobronchial Electrcautery 2012

45. Endobronchial stents 2012

46. Pleurocentesis 2012

47. Pleurocentesis 2012

48. Abram’s Pleural Biopsy Needle 2012

51. !! בהצלחה 2012