1 / 18

Respiratory Failure

Respiratory Failure. Kenney Weinmeister M.D. Definition. Demand overwhelms the capacity of the system Hypoxemia: PaO2 < 60 mmHg Hypercarbia: PaCO2 > 49 mmHg. Alveolar-arterial Oxygen Tension Difference. PAO2 = FIO2 x atmos. pres. - PaCO2/R PAO2 = 150 - PaCO2/0.8

shirina
Download Presentation

Respiratory Failure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Respiratory Failure Kenney Weinmeister M.D.

  2. Definition • Demand overwhelms the capacity of the system • Hypoxemia: PaO2 < 60 mmHg • Hypercarbia: PaCO2 > 49 mmHg

  3. Alveolar-arterial Oxygen Tension Difference • PAO2 = FIO2 x atmos. pres. - PaCO2/R • PAO2 = 150 - PaCO2/0.8 • P(A-a) O2 gradient = 2.5 + 0.21 x age (yr)

  4. Duration of Hypercarbia • Acute minutes to hours • Acute Change in pH = .008 x change PCO2 • Chronic days • Chronic Change in pH = .003 x change PCO2 • Mixed • Change in pH is >.003 <.008

  5. Hypoxemic Respiratory Failure • Hypoventilation • Normal A-a gradient • V/Q mismatch • Elevated A-a gradient • Significantly improves with !00% oxygen • Right to left shunts • Elevated A-a gradient • Does not significantly improve with 100% oxygen

  6. Hypercapnic Respiratory Failure • Hypoventilation • Extrapulmonary disorders • Severe V/Q mismatch

  7. Extrapulmonary Respiratory Failure • Hypoxemic with normal A-a gradient • Hypercarbic acute or chronic • CNS • PNS • Respiratory muscles • Chest Wall • Pleura • Upper Airways

  8. Central Nervous System Causes of Respiratory Failure • Drugs • Hypothyroidism • Brainstem injury or tumor • Primary alveolar hypoventilation • Central sleep apnea

  9. Spinal cord Tetanus Strychnine ALS Guillain Barre Synd. Shellfish Bilateral phrenic nerve palsy Diptheria Pseudocholinesterase deficiency Myasthenia Gravis Eaton-Lambert Botulism Organophosphate poisoning Peripheral Nervous System Causes of Respiratory Failure

  10. Respiratory Muscle Dysfunction • Muscular dystrophies • Myotonic dystrophies • Polymyositis • Periodic paralysis • Electrolyte disorders

  11. Chest Wall and Pleural Disorders • Kyphoscoliosis • Obesity hypoventilation • Flail chest • Fibrothroax • Thoracoplasty • Ankylosing spondylitis

  12. Acute epiglottitis Acute laryngeal edema Anaphylaxis Trauma Foreign body aspiration Retropharyngeal hemorrhage Bilateral vocal cord paralysis Tracheal stenosis Tracheomalasia Tumors Upper Airway Obstruction

  13. Pulmonary Causes of Respiratory Failure • Lower airway • Asthma, COPD • Parenchymal • Pulm. Edema, infections, interstitial lung dz • Pulmonary vasculature • PE, Primary pulmonary hypertension

  14. Options for Ventilation • Noninvasive positive pressure ventilation • Invasive positive pressure ventilation • Negative pressure ventilation

  15. Noninvasive Positive Pressure Ventilation • Continuous positive airway pressure • Hypoxemia • Functional airway obstruction • Bilevel positive airway pressure • Hypercarbia • COPD • Neuromuscular or chest wall disorders

  16. Invasive Positive Pressure Ventilation • Acute decompensation • Fail NIPPV • Mechanical Airway obstruction • Protect airway

  17. Negative Pressure Ventilation • Chronic respiratory failure • Neuromuscular disease • No functional airway obstruction

  18. Conclusion • Differentiate type of respiratory failure • Hypoxemic vs hypercarbia • Hypoventilation vs V/Q mismatch • Determine if chronic or acute • Most often acute respiratory failure due to V/Q mismatch

More Related