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Fatal & Near-Fatal Asthma

Fatal & Near-Fatal Asthma. Rising to the challenge. Robert Donovan MD FACEP Medical Director PHI California Chief of Staff Doctors Medical Center. Asthma. Asthma in Ancient Times. Ebers Papyrus. Maimonides. “No magic cure for asthma”

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Fatal & Near-Fatal Asthma

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  1. Fatal & Near-Fatal Asthma Rising to the challenge Robert Donovan MD FACEPMedical Director PHI CaliforniaChief of Staff Doctors Medical Center

  2. Asthma

  3. Asthma in Ancient Times Ebers Papyrus

  4. Maimonides • “No magic cure for asthma” • “Asthma often starts with a common cold during the rainy season” • “The air pollution in Cairo may in part be responsible”

  5. Cairo Insert obligatory vacation photo here Cairo is here!

  6. Pathophysiology of Asthma

  7. Inflammatory cells in asthma • Mast cells • Eosinophils • Macrophages • Activated T lymphocytes

  8. Autopsy Findings in Fatal Asthma  smooth muscle wall thickness inflammation

  9. Severe Asthma • 5% to 10% of asthmatics • Pts. are particularly hard to manage • Still poorly understood

  10. Severe Asthma

  11. + Skin Tests +++ Skin Tests Severe Asthmatics

  12. Female gender Poor management skills Smoking/drugs/alcohol Prior severe attacks Age > 40 Ability to sense & respond to airway stimulus

  13. Is it truly asthma?

  14. Precipitants of Near Fatal Asthma • Air pollution • Viral URIs • Non-compliance • Emotional stress • Weather changes • Heavy allergen exposure

  15. How Near-Fatal Asthma presents 10% - Quickly 90% - Slowly…

  16. Physical Exam • Dyspneic, scared, and diaphoretic • Sitting upright or tripod, tachycardic and tachypneic, and using accessory muscles. • Auscultation reveals diffuse wheezing or, worse, no breath sounds at all.

  17. Measure Peak Flow? • FEV1 usually low, often can’t be measured • Although it might be helpful, ill patients won’t even try • Failure to FEV1 – not good!

  18. Lab Findings • WBC might be  In allergic patients, the % eosinophils might be  • Serum K+ is often low •  lactate is common • ? high-dose catecholamine therapy • ? increased production by respiratory muscles and decreased clearance due to circulatory failure

  19. ? ABG ? • Blood gas might help • Supplemental O2 generally will correct hypoxia • CO2 might be  or  • A steadily rising PaCO2  impending respiratory collapse • Changes in the pH might be the most help

  20. Management Anticipate bad things happening IV, O2, monitoring Bronchodilators Corticosteroids Plan for ICU Admission Adjunctive and Experimental Therapy

  21. Albuterol • Mainstay Bronchodilator • MDI’s don’t work • Side effects are tolerable

  22. Atrovent (ipratropium) • Atrovent (with high-dose albuterol) may improve bronchodilation • Dose of 0.5 mg delivered by nebulization q 1 hour • In our ED, routinely added to full-strength Albuterol nebulizer

  23. Corticosteroids in Near-Fatal Asthma • Essential Treatment • Effects may be within 1-2 hours although a response may not be apparent for days • Possible role for inhaled corticosteroids in addition

  24. Magnesium • Interferes with calcium-mediated smooth muscle contraction • Decreases acetylcholine release from parasympathetic nerve endings • Can cause hypotension and loss of deep tendon reflexes. • 2 grams IV over 20 minutes

  25. BiPAP? • Might be worth a trial • Some supporters • If you can get the patient to keep it on…..

  26. Ketamine Case Presentation • 47 yo male: Hx Asthma, Smoker, Depression, COPD • Began with productive cough  yellow/green sputum • Treated in ER; released • Returned 1 hour later – much worse • Tripod, tachypneic, 87% sats. • Initial ABG pH 7.42 pCO2 46 PO2 96% (with o2) • Worsened despite treatment; intubated • Got even worse • difficult to ventilate • high peak airway pressures >80 cmH2O • pH 7.04; pCO2 91; pO2 86% on 100% FiO2.

  27. KetamineStarted

  28. Other Possibilities • Theophylline • Heliox (70% Helium 30% Oxygen) • IV montelukast • IV terbutaline • Cardio-Pulmonary Bypass

  29. What if things worsen? Intubation!

  30. Intubation • 100% O2 • Get back-up airways out • Best person does it • Do full RSI • Decompress the stomach • Keep them paralyzed • DON’T put them on a ventilator! (at first) • You take over the initial bagging of the patient

  31. Dynamic Hyperinflation Premature Ventilator = Death

  32. Normal Lung Dynamics

  33. Dynamic Hyperinflation

  34. Dynamic Hyperinflation • Barotrauma • Hemodynamic compromise from  intrathoracic pressure • Decreased venous return •  Pulmonary vascular resistance • Decreased cardiac output

  35. Ways to identify Dynamic Hyperinflation • High Peak airway pressure • Presence of Intrinsic positive end-expiratory pressure (autoPEEP) • High Plateau Pressure • Clinical

  36. If BP and  Airway Pressure • Think tension pneumothorax or DHI stacking • Immediately disconnect pt. from vent and slowly bag, or not at all • If due to DHI, BP should quickly • If no change, needle both sides of the chest – now!

  37. How to Minimize DHI • Do what it takes to ensure enough time to exhale • Ways to increase expiratory phase include: • Increasing the inspiratory flow rate in order to decrease inspiratory time - good • Decreasing the Tidal Volume. - better • Decreasing the respiratory rate - best

  38. Tidal Volume: 1 liter Resp. Rate : 10 Insp. Flow : 60 Liters/min Insp/Exp. Ratio = 1:5 Expiration time : 5 seconds Tidal Volume: 1 liter Resp. Rate : 10 Insp. Flow : 120 Liters/min Insp/Exp. Ratio = 1:11  Expiration time : 5.5 seconds

  39. Tidal Volume: 1 liter Resp. Rate : 10 Insp. Flow : 60 Liters/min Insp/Exp. Ratio = 1:5 Expiration time : 5 seconds Tidal Volume: 1 liter Resp. Rate : 6 Insp. Flow : 60 Liters/min Insp/Exp. Ratio = 1:9  Expiration time : 9 seconds

  40. VentilatorKnobology

  41. Goal - Avoid Hypoxia • Aim for SaO2 >90% - 95% • For the short term– keep the patient sedated and paralyzed • PEEP is generally not useful • Be aware of theoretical concerns of too much oxygen promotes free radicals

  42. How I determine a respiratory rate • Use your Stethoscope !! • Don’t be surprised with rates of 6-10 breaths per minute at first • Start the ventilator at this rate, use stethoscope to determine increases in rate

  43. Goal – Minimize Volu-trauma • Aim for Tidal Volume 0f 8 to 10 ml/kg.min • Aim for rate of 10 – 12 breaths per minute Tidal Volume (TV) * Breathing Rate =Minute Volume (E)10 ml/kg.min * 12/min = 120 ml/kg.min

  44. Oxygen • B-2 Agonists • IV Steroids/MgSO4 • “Extras” • Be watchful • If intubated: • Slow & Low • Add ketamine

  45. Robert Donovan MD FACEP Fatal & Near Fatal Asthma doctor@donovans.com

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