Pulmonary Pearls

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Review of common pulmonary medical problems
Edward Omron MD, MPH, FCCP
Pulmonary Medicine
Morgan Hill, CA 95037

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  • There are 3 reasones why one should obtain a blood gas:
  • This is a typical printout from a blood gas report:
  • Recall altitiude Recall RS Allows to assess properly if the lungs are transferring loxygen appropriately into the blood
  • Pulmonary Pearls

    1. 1. Pulmonary Pearls Edward Omron MD, MPH Pulmonary/Critical Care Medicine
    2. 2. History <ul><li>74 year-old woman presents with 4 days cough, chills, dyspnea and fever </li></ul><ul><li>Hemoptysis with right sided pleuritic chest pain x2 days </li></ul><ul><li>Unable to walk due to dyspnea </li></ul><ul><ul><li>35 pack year tobacco use </li></ul></ul><ul><ul><li>Assisted care facility </li></ul></ul><ul><ul><li>Recent hospital admission for complicated UTI treated with levofloxacin </li></ul></ul>
    3. 3. Physical Exam <ul><li>Respiratory distress </li></ul><ul><li>Temp 101.8 F </li></ul><ul><li>Heart Rate 110 </li></ul><ul><li>Blood pressure 80/55 mm Hg </li></ul><ul><li>Dullness to percussion on right side with crackles </li></ul>
    4. 4. Initial Tests <ul><li>ECG: Sinus Tachicardia with LVH </li></ul><ul><li>WBC: 18,600 </li></ul><ul><li>Creatinine: 1.5, BUN 47 </li></ul><ul><li>ABG </li></ul><ul><ul><li>pH 7.32 </li></ul></ul><ul><ul><li>PaCO2 = 47 mm Hg </li></ul></ul><ul><ul><li>PaO2 = 58 mm Hg on 4 L NC </li></ul></ul>
    5. 5. ER Chest X-RAY
    6. 6. What is the most likely pathogen in this patient? <ul><li>S pneumoniae </li></ul><ul><li>H influenzae </li></ul><ul><li>S aureus </li></ul><ul><li>P aeroginosa </li></ul><ul><li>K pneumoniae </li></ul><ul><li>M tuberculosis </li></ul><ul><li>Other </li></ul>
    7. 7. Initial Treatment in the ER <ul><li>Right IJ central venous access </li></ul><ul><li>Fluid bolus 1 Liter 0.9% NS </li></ul><ul><li>Oxygen converted to 40% venturi mask </li></ul><ul><li>Bipap on the way </li></ul><ul><li>Albuterol / Atrovent neb treatments </li></ul><ul><li>Transduced CVP < 8 mm Hg after fluid bolus and second 1 L 0.9% NS given </li></ul>
    8. 8. What antibiotic regimen would you prescribe in the ER? <ul><li>Beta Lactam </li></ul><ul><li>Respiratory quinolone </li></ul><ul><li>3 rd Generation Cephalosporin+macrolide </li></ul><ul><li>3 rd Generation Cephalosporin+ respirotory quinolone </li></ul><ul><li>Carbopenem+ aminoglycoside </li></ul><ul><li>Vancomycin+ respiratory quinolone </li></ul><ul><li>Vancomycin + extended spectrum penicillin + aminoglycoside </li></ul><ul><li>Zyvox, Zosyn, levafloxacin </li></ul><ul><li>Other </li></ul>
    9. 9. Initial antibiotics given in the ER <ul><li>Ceftriaxone 2 gram and levafloxacin 750 mg </li></ul><ul><li>Rationale: </li></ul><ul><ul><li>Most likely diagnosis was thought to be CAP (Strep pneumo + H influ) </li></ul></ul><ul><ul><li>Atypical pathogen coverage for legionella </li></ul></ul>
    10. 10. Follow Up <ul><li>Urine legionella antigen negative </li></ul><ul><li>Sputum: gram + cocci in clusters 4+ which later grew out MRSA </li></ul><ul><li>Blood Cultures: MRSA, PVL+ or CA-MRSA </li></ul><ul><li>Community Acquired MRSA </li></ul>
    11. 11. Community Acquired MRSA Sensitivity in this patient <ul><li>Oxacillin Resistant </li></ul><ul><li>Fluoroquinolone Intermediate </li></ul><ul><li>Macrolide Resistant </li></ul><ul><li>Cephalosporin Resistant </li></ul><ul><li>Vancomycin Sensitive </li></ul><ul><li>Clindamycin Sensitive </li></ul><ul><li>Linezolid Sensitive </li></ul><ul><li>Septra Sensitive </li></ul>
    12. 12. CA-MRSA Pneumonia <ul><li>MRSA is an increasing threat in all forms of pneumonia </li></ul><ul><li>CA-MRSA is the newest threat to hospitalized patients with pneumonia </li></ul><ul><li>“ Superbug” </li></ul><ul><ul><li>Enhanced antibiotic resistance </li></ul></ul><ul><ul><li>Higher mortality than MSSA strains </li></ul></ul><ul><ul><li>Expresses multiple virulence factors </li></ul></ul>
    13. 13. CA-MRSA: 48 hours of destruction Admission 48 hours later
    14. 19. Healthcare Acquired Pneumonia <ul><li>Empiric regimen </li></ul><ul><ul><li>Vancomycin 1.5 gm IV </li></ul></ul><ul><ul><li>Zosyn 3.375-4.5 grams q6 or Fortaz 1.5 gm to 2 gm q8 </li></ul></ul><ul><ul><li>Tobramycin 5 mg/kg once daily </li></ul></ul><ul><ul><li>Pharmacy to DOSE! </li></ul></ul><ul><ul><li>ID or Pulmonary to de-escalate therapy next day. </li></ul></ul>
    15. 20. 59 yo with dyspnea and increased work of breathing <ul><li>ABG: pH = 7.27, PCO2= 56, PaO2 = 60 </li></ul><ul><li>Pulse 125, RR = 32, BP= 120/80, Sat 90% RA </li></ul><ul><li>WBC 17K, BUN = 30, Creat 1.2 </li></ul><ul><li>Conversational dyspnea but alert and oriented </li></ul><ul><li>Where should this patient go? </li></ul><ul><ul><li>ICU </li></ul></ul><ul><ul><li>Monitored Bed </li></ul></ul><ul><ul><li>Floor </li></ul></ul><ul><li>How should we manage the airway? </li></ul>
    16. 21. CXR
    17. 22. COPD Management Non-invasive ventilation <ul><li>Very useful in acute exacerbation especially with dynamic hyperinflation and muscle failure. </li></ul><ul><li>Can be tried even in hypercapneic narcosis. </li></ul><ul><li>Night time use for severe COPD with hypercapnia may be of benefit if tolerated. </li></ul>
    18. 23. <ul><li>Non-invasive ventilation </li></ul><ul><ul><li>Hypercapneic failure PCO2> 45 mg Hg </li></ul></ul><ul><ul><ul><li>BIPAP: Initial 10 IPAP/ 5 EPAP cm H2O with FIO2 bleed in to maintain sats at 90%, humidified </li></ul></ul></ul><ul><ul><li>Hypoxic and Hypercapneic ventilatory Failure </li></ul></ul><ul><ul><ul><li>Bipap: Initial 10 IPAP /10 EPAP cm H2O with FiO2 Bleed in to maintain sats at 90%, humidified </li></ul></ul></ul><ul><ul><li>Congestive Heart Failure </li></ul></ul><ul><ul><ul><li>CPAP at 10 cm H2O with FIO2 Bleed in to maintain sats at 90%, humidified </li></ul></ul></ul>
    19. 24. COPD Management <ul><li>For Acute Exacerbations </li></ul><ul><ul><li>Injudicious administration 02 in CO2 retaining pts may cause acute rise in PaCO2. </li></ul></ul><ul><ul><ul><li>Loss of alveolar hypoxemic vasoconstriction causes flooding of vasculature with alveolar CO2 </li></ul></ul></ul><ul><ul><ul><li>NOT LIKELY “loss of hypoxemic drive.” </li></ul></ul></ul><ul><ul><ul><ul><li>Appears as such because sudden rise in PaCO2 causes narcosis. </li></ul></ul></ul></ul><ul><ul><ul><li>Titrate to 90% at all times </li></ul></ul></ul><ul><ul><li>Avoid respiratory depressants </li></ul></ul>
    20. 25. Severe COPD Normal
    21. 26. Severe COPD Normal
    22. 27. ABG INDICATION <ul><li>Oxygenation </li></ul><ul><li>Ventilation </li></ul><ul><li>Acid-Base Status </li></ul><ul><li>The most sensitive indicator of physiologic stress irrespective of etiology </li></ul>
    23. 28. Blood Gas Report( Arterial ) <ul><li>pH (No Units) 7.35-7.45 </li></ul><ul><li>PaCO 2 (mm Hg) 35-45 </li></ul><ul><li>PaO 2 (mm Hg) 110 - 0.5(age) </li></ul><ul><li>HCO 3 - (mmol/L): calc. 22-26 </li></ul><ul><li>B.E. (mmol/L) -2 to 2 </li></ul><ul><li>O 2 saturation: calc. >90% </li></ul>
    24. 29. Changes in PO 2 and PCO 2 as oxygen moves from atmosphere to arterial blood
    25. 30. <ul><li>Alveolar arterial O2 gradient </li></ul><ul><ul><li>The difference in oxygen pressure between alveolar air and arterial blood </li></ul></ul><ul><ul><li>INCREASE in alveolar / arterial pressure gradient indicates either lung disease or a problem with oxygen transfer </li></ul></ul><ul><ul><li>PAO 2 calculated from Alveolar Air Equation </li></ul></ul><ul><ul><li>PaO 2 derived from a blood gas report </li></ul></ul>
    26. 31. ANALYSIS OF OXYGENATION <ul><li>Alveolar Gas Equation </li></ul><ul><ul><li>PAO 2 = FIO 2 (P B - 47) - 1.2(PaCO 2 ) </li></ul></ul><ul><ul><li>PAO 2 defines upper limit of PaO 2 </li></ul></ul><ul><ul><li>FIO 2 is 21% at all altitudes </li></ul></ul><ul><ul><li>Factor 1.2 determined by RQ </li></ul></ul><ul><ul><li>Water vapor pressure = 47 mm Hg </li></ul></ul><ul><ul><li>PAO 2 = 150 - 1.2(PaCO 2 ) at room air </li></ul></ul><ul><ul><li>PAO 2 = 102 </li></ul></ul>
    27. 32. Alveolar-Arterial Oxygen Difference <ul><li>A-aDo 2 = PAO 2 -PaO 2 (from ABG) </li></ul><ul><li>Insight in the patients state of gas exchange </li></ul><ul><ul><li>If elevated, defect in gas exchange </li></ul></ul><ul><ul><li>Proper interpretation of the PaO 2 </li></ul></ul>
    28. 33. Changes in PaO 2 and PAO 2 with age
    29. 34. Arterial Oxygen Values <ul><li>Age L.L. PaO2 U.L. A-aDo2 </li></ul><ul><li>20 84 17 </li></ul><ul><li>30 81 21 </li></ul><ul><li>40 78 24 </li></ul><ul><li>50 75 27 </li></ul><ul><li>60 72 31 </li></ul><ul><li>Max A-aDo2 = 2.5 + Age/5 </li></ul><ul><li>Hypoxemia PaO2 < 70 (relative) </li></ul>
    30. 35. Changes in P(A-a)O 2 with FIO 2
    31. 36. Causes of a low PaO 2 <ul><li>P(B): Altitude </li></ul><ul><li>Alveolar Hypoventilation(Nl A-a Do2) </li></ul><ul><li>V/Q mismatch </li></ul><ul><li>Shunt </li></ul><ul><li>Diffusion Impairment </li></ul><ul><li>Decreased mixed / central venous O 2 content </li></ul>
    32. 37. <ul><li>A 73 yo is brought to the emergency room comatose. The family states she had become confused and had swallowed an excess number of sleeping pills. ABG while breathing room air (FIO 2 = 0.21) shows the PaO 2 , is 42 mm Hg, the PaCO 2 , is 75 mm Hg, and the pH is 7.10. Why is her PaO 2 reduced? </li></ul>
    33. 38. Alveolar Hypoventilation <ul><li>No increase in P(A-a)O2 gradient </li></ul><ul><li>PAO 2 = 150-1.2 (75) = 60 </li></ul><ul><li>A-a gradient = 60 – 42 = 18 Nl </li></ul><ul><li>PaO2 +PCO2 = 120 </li></ul>
    34. 39. Pulse Oximetry <ul><li>Binding sites for O 2 are heme groups </li></ul><ul><li>OXYGEN SATURATION </li></ul><ul><ul><li>% of all heme sites saturated with O2 </li></ul></ul><ul><li>Measures the difference in the light absorbance characeteristics between Oxy Hb and Deoxy Hb </li></ul><ul><li>SpO2 = Oxy Hb x 100 </li></ul><ul><li>Oxy Hb + Deoxy Hb </li></ul><ul><li>ABG SaO2 is a calculated value from PaO2 </li></ul>
    35. 40. Pulse Oximetry Whole Blood PaO2 SaO2 SpO2: Pulse Oximetry ABG
    36. 41. Problem <ul><li>28 yo pt with fevers,chills, SOB,cough </li></ul><ul><ul><li>Taking Dapsone for PCP prophylaxis </li></ul></ul><ul><ul><li>ABG: PaO2 90, PaCO2 35.2, pH 7.43, SaO2 100% </li></ul></ul><ul><ul><li>Pulse oximeter 89% </li></ul></ul><ul><ul><li>PCP Pneumonia, started on Septra, Clinda, and Prednisone </li></ul></ul><ul><ul><li>ABG: PaO2 378, PaCO2 of 35, pH 7.42, SaO2 100% </li></ul></ul><ul><ul><li>Pulse Oximeter 83% </li></ul></ul><ul><ul><li>Whats Happening? </li></ul></ul>
    37. 42. Methemoglobin <ul><li>Oxidation of Fe++ to Fe+++ state </li></ul><ul><li>Met-Hb depresses the SpO2 reading </li></ul><ul><li>Dapsone is an oxidant </li></ul><ul><li>Met-Hb depresses the SpO2 to 80’s </li></ul><ul><ul><li>Further increases in Met-Hb do not depress SpO2 </li></ul></ul><ul><li>Methylene Blue administration is Rx </li></ul>
    38. 44. Co-oximetry <ul><li>SpO2 = Oxy-Hb </li></ul><ul><li>Oxy-Hb+Deoxy-Hb+CO-Hb+Met-Hb </li></ul>
    39. 45. Oximetry <ul><li>54 yo WM with headaches, dyspnea and a Kerosene heater at home </li></ul><ul><ul><li>ABG: PaO2 = 89, PaCO2 = 38, pH = 7.43 </li></ul></ul><ul><ul><li>SaO2 from ABG= 98% </li></ul></ul><ul><ul><li>Pulse Oximetry = 98% </li></ul></ul><ul><ul><li>Whats the problem? </li></ul></ul>
    40. 46. Oximetry <ul><li>Carboxyhemoglobin: Hb +CO </li></ul><ul><ul><li>Does not affect PaO2 or pulse oximetry </li></ul></ul><ul><ul><li>P.O. reads CO as oxyhemoglobin </li></ul></ul><ul><ul><li>Need co-oximetry if suspected </li></ul></ul><ul><li>Follow Up: </li></ul><ul><ul><li>PaO2 = 79, PaCO2 = 31, SpO2 = 53%, pH =7.36 </li></ul></ul><ul><ul><li>CO-Hb46% </li></ul></ul>

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