Continuous Positive Airway Pressure

1. Continuous Positive Airway Pressure For EMT Providers State Education & Training Committee December 2012

2. The student will be able to correctly utilize service specific CPAP devices in a respiratory compromised patient [img]http://hammondems.com/images/d_1976.jpg Goal

3. Objectives • At the completion of this training, the BLS provider will: • Describe respiratory anatomy and physiology • Verbalize understanding of respiratory disorders / illnesses • Appreciate the benefits and limitations of CPAP in alleviating patient symptoms • List indication and contraindications for use.

4. Anatomy and Physiology of Respiration

5. Nose / Mouth Trachea Mainstem Bronchi Secondary Bronchi Tertiary Bronchi Bronchioles Terminal Bronchiole Alveoli Diaphragm http://www.uni.edu/schneidj/webquests/spring04/offtowar/respiratory.html Respiratory Physiology

6. Negative Pressure • Respiration driven by process of negative intrathoracic pressures • Negative pressure • Initiates inhalation and acquisition of O2 • Assists to increase intrathoracic blood flow • Hemodynamic Effects • Equalization of pressures • initiates exhalation and elimination of CO2

7. Cartilage structures give way to smooth muscle May divide up to 25 times before reaching terminal bronchioles Bronchi / Bronchioles • http//medicalpicturesinfo.com/bronchial-tree/

8. Alveoli • Expand and contract with breathing • Contact with pulmonary capillary beds for gas exchange • Inside surface coated with surfactant • Prevents aveoli from sticking together • Keeps alveoli open • Atelectasis

9. http://www.teachpe.com/anatomy/respiratory_system.php Mechanics of Respiration

10. Lung volume at end of normal exhalation Muscles of respiration are completely relaxed http://www.lakesidepress.com/pulmonary/htm Functional Residual Capacity

11. Gas Exchange • http://www.uic.edu/classes/bios/bios100/lectures/circ.htm

12. Oxygenation • Process of getting oxygen to end organs and tissues • Inhaled through lungs • Picked up from alveoli on RBCs • Off-loaded in exchange for CO2 • Measured by pulse oximetry (SpO2)

13. Ventilation • Process to eliminate carbon dioxide (waste product of energy production) • Carried back through venous blood • Eliminated through exhalation • Measured by capnography

14. Capnography • The capnogram wave form begins before exhalation and ends with inspiration. Exhalation comes before inhalation • http://www.lusotech.com.br/catalogo/continuous-waveform-capnography

15. Capnography Waveform • http://medicscribe.com/:ffeb_network_search_context=blog/amp;s=pain/management

16. Respiratory Disorders

17. Respiratory Disorders A combination of many disease processes responsible for emergencies related to ventilation, diffusion and perfusion.

18. Respiratory Distress • Subjective indication of some degree of difficulty breathing • Causes • Upper or lower airway obstruction • Inadequate ventilation • Impaired respiratory muscle function • Impaired nervous system • Trauma • Bronchitis, pneumonia, cancer

19. Respiratory Failure • Clinical state of inadequate oxygenation, ventilation or both. • Often end-stage of respiratory distress • Signs: • Tachypnea (early) • Bradypnea or apnea (late) • Increased, decreased, or no respiratory effort • Tachycardia (early) • Bradycardia (late) • Cyanosis • Altered Mental Status

20. Mechanism of Heart Failure • Frequently a chronic, yet manageable condition • Left ventricle fails to work as effective pump • Blood volume backs up into pulmonary circulation • Most often caused by: • Volume overload • Pressure overload • Loss of myocardial tissue • Impaired contractility

21. Pulmonary Edema • Cardiac and respiratory system impairment • Acute and critical emergency • Filling of lungs with fluid • Washes away surfactant • Creates pink froth in sputum • Prevents alveoli from expanding • Significantly reduces or eliminates ability for gas exchange to occur

22. Asthma • Reactive airway disorder • Exacerbation precipitated by extrinsic or intrinsic factors • Characterized by reversible bronchial smooth muscle contraction, increased mucus production and inflammatory airway changes • Persistent signs and symptoms can indicate a tenfold increase in the work of breathing

23. Evolution of asthma attack Mucus thickens and accumulates plugging airways Mucosal edema develops Muscle spasms constrict small airways Breathing becomes labored Exhalation becomes difficult http://asthma-ppt.com/asthma-pictures.html Asthma

24. Caution

25. Chronic Obstructive Pulmonary Disease • Obstructive lung disease • Triad of distinct diseases that often coexist • Asthma • Chronic bronchitis • Emphysema • Traditionally refers to patients with combination of chronic bronchitis and emphysema

26. Chronic Bronchitis • Bronchi become filled with excessive mucus • Alveoli are not affected • Diffusion of gas remains relatively normal • Patients develop low oxygen pressures (PO2) and hypoventilation • Hypoventilation leads to high levels of CO2 and low levels of O2

27. Results from pathological changes in the lung Permanent abnormal enlargement of air spaces beyond terminal bronchioles Collapse of the bronchioles Destruction of the alveoli http://health.allrefer.com/health/chronic-obstructive-pulmonary-disease-emphysema.html Emphysema

28. Patients have some resistance to airflow, primarily on exhalation Hyper-expansion caused by air trapped in the alveoli Breathing becomes an active process Sanders, M.J. (2005) Paramedic Textbook (3rd ed.) St. Louis: Mosby-Elsevier Emphysema

29. Emphysema • Bleb formation • Risk of pneumothorax • Interior airway pressure • CO2 Retention • Potential worsening with CPAP

30. Continuous Positive Airway Pressure

31. The use of CPAP prehospitally reduces the need for intubation by 30% and reduces mortality by 20% • Annals of Emergency Medicine, September 2008

32. Non-invasive ventilation Continuous O2 delivered at a set positive pressure throughout the respiratory cycle www.ems1.com/cpap-for-ems CPAP

33. Positive Pressure • PUSHES air into the chest • Overcomes airway resistance • Bag valve mask • Demand valve • Intubation / mechanical ventilation • CPAP

34. Effects of CPAP • Increases functional residual capacity • Increases alveolar surface area available for gas exchange • Increases oxygen diffusion across alveolar membranes • Reduced work of breathing

35. How CPAP Works • Maintains constant level of airway pressure • Keeps alveoli open (asthma, COPD) • Moves fluid into vasculature (pulmonary edema) • Improves gas exchange • Buys time for medications to work

36. Indications • Severe Respiratory Distress / Respiratory Failure • Accessory muscle use? • Persistent hypoxia despite appropriate / aggressive oxygen therapy? • Marked increased work of breathing? • Inability to speak full sentences? • Differentiate Pulmonary Edema versus other Respiratory Disorder

37. Contraindications • Respiratory rate < 10 breaths / minute • Systolic blood pressure < 100 mmHg • Confusion • Inability to understand directions and cooperate with application of CPAP • History of pneumothorax • History of recent tracheo-bronchial surgery • Active nausea or vomiting • Despite antiemetic therapy by paramedics

38. Limitations • CPAP is not a mechanical ventilator • Tight mask seal can create claustrophobic response • Consider allowing patient to self-seal (hold own mask) until initial benefits recognized • CPAP is powered by on-board oxygen supply

39. Oxygen Utilization Oxygen Demand

40. Summary Pre-hospital studies have proven the effectiveness of CPAP in treating patients with severe respiratory distress, regardless of disease process.

41. ANY QUESTIONS

42. Special Thanks To: Peter Canning for time and effort in initial development of program David Bailey for contributions of supplemental information to enhance presentation Richard Sanders for development of glossary of terms Nancy Brunet for final project coordination

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44. Practical Skills Session