Airway

1. Chapter 7 Airway

2. Case History You respond to a motor vehicle crash. On arrival, you find a demolished vehicle with a 40-year-old unresponsive, cyanotic male slumped over the wheel of his car. He is making gurgling noises as he breathes shallowly at a rate of 8 times per minute. Blood and loose teeth are in the upper airway.

3. Analysis of the Case • Rapid extrication with immobilization of cervical spine • Airway: jaw thrust, suction, oropharyngeal airway • Mouth-to-mask or bag-valve-mask with supplemental oxygen, or flow-restricted, oxygen-powered ventilator • Continuously monitor signs of adequate ventilation and oxygenation

4. Overview • Management of the airway and ventilation represent the first and most critical steps in most serious emergencies. • Humans are oxygen-dependent organisms. • Three critical priorities • Airway • Breathing • Oxygenation

5. Assess the Airway, Breathing, Circulation in Every Patient • Assess for adequate vs. inadequate breathing to determine if the patient needs treatment to: • Maintain airway • Support ventilation • Supplement oxygenation

6. Airway Interventions • Manual techniques • Head tilt/chin lift • Jaw thrust • Mechanical techniques • Oropharyngeal airways • Nasopharyngeal airways • Suction

7. Ventilation Interventions • Mouth-to-mask • Bag-valve-mask • Flow-restricted oxygen-powered ventilator

8. Oxygen Interventions • Supplemental oxygen for patient with adequate ventilation • Nonrebreather • Nasal cannula (when patient cannot tolerate mask) • Blow-by oxygen for children (when patient cannot tolerate mask) • Positive pressure • Mouth-to-mask with supplemental oxygen • Bag-valve-mask with supplemental oxygen • Flow-restricted oxygen-powered ventilator

9. Review of Anatomy and Physiology • Three main functions of respiratory system • Delivery of oxygen from atmosphere to blood • Removal of carbon dioxide from the blood to the atmosphere • Creation of voice

10. Structures and Function • Nose • Pharynx • Epiglottis and larynx • Trachea • Bronchi and bronchioles • Alveoli

11. Lungs • Two cone-shaped organs consisting of: • Bronchi, bronchioles, and alveoli • Suspended in thoracic cavity and separated by mediastinum • Surrounded and protected by ribs thoracic spine, sternum, clavicle, and muscles • Outer surface of lungs and inner surface of thoracic cavity lined with pleura

12. Elasticity of the Lungs • Lungs have natural tendency to collapse – “elasticity.” • Lungs fill thoracic cavity because of relative “negative” pressure between pleura. • Pneumothorax disturbs relationship; lung collapses

13. Muscles of Breathing • Cause chest movement that results in air exchange • Quiet breathing involves two muscles: • Diaphragm • External intercostals

14. Inspiration (Active Process) • Diaphragm increases inferior-superior diameter of chest cavity • External intercostals increase anterior-posterior, lateral dimensions • Increase in size results in more volume, less pressure relative to atmosphere, and air rushes in. • Inspiration continues until pressure within lung and atmosphere equalizes.

15. Expiration (Passive Process) • Respiratory muscles relax and elastic recoil of lungs. • Chest cavity decreases in size - less volume, pressure increases relative to atmosphere. • Air exits airway until atmosphere and chest pressure are equal.

16. Accessory Muscles of Breathing • Needed for forceful breathing • Key sign of respiratory distress • Accessory muscles of inspiration increase the size of chest cavity by further lifting rib cage and increasing diameter • Inspiratory muscles – scalene (neck), sternocleidomastoids, parasternal (chest)

17. Accessory Muscles of Expiration • Assist in forcefully evacuating air • Pull down on ribs and compress abdominal contents into diaphragm • Expiratory muscles — internal intercostals and abdominal muscles • Active accessories indicate respiratory distress, signs include bulging neck muscles, retraction between ribs, abdominal distention.

18. Respiratory Volumes • Minute volume • The amount of air delivered to the lungs each minute • Equals tidal volume times the number of breaths per minute • Normal minute volume for an adult • Tidal volume (approx 500 mL/breath) x respiratory rate (normal range is 12-20/minute) • Example: MV = 500 mL/breath x 12 breaths/min or 6000 mL/min

19. Using Minute Ventilation An unresponsive male has respirations of 6 per minute and no noticeable chest rise. Is his minute ventilation adequate to support life?

20. Using Minute Ventilation • Provide rescue breathing to the patient with hypoventilation. • How do you gauge adequate volume per breath? What is the tidal volume? • How many breaths a minute should be administered? • What is the minute ventilation?

21. Ventilation • Adequate ventilation • Respiratory rate of 12 - 20 with visible chest rise • Alert mental state, muscle tone, and moving air • Normal skin color • Inadequate ventilation (respiratory failure) • Very slow ventilation • Very rapid ventilation with minimal or no chest rise • Altered mental state, poor muscle tone, poor air flow, cyanosis

22. Alveolar-Capillary Exchange • Diffusion • Movement of gases from an area of higher concentration to an area of lower concentration • Oxygen and carbon dioxide diffuse at the lungs and at the tissues. • Lungs: oxygen moves from the alveoli (higher) to the blood (lower) • Tissues: oxygen moves from the blood (higher) to the tissues (lower) • Fluid in the alveoli can impair diffusion and lead to hypoxia.

23. Clinical Application Nerve agents, such as sarin, cause muscle paralysis and excessive secretions, including in the lungs. Victims die a respiratory death, from hypoventilation and/or “drowning in their own secretions.”

24. Neuroregulation of Breathing • CNS monitors • Carbon dioxide, oxygen, and pH • Directs respiratory muscles to rate and depth of ventilation, as needed • Carbon dioxide primary drive for normal person • Patients with COPD • Oxygen may be primary drive for COPD • Use caution when administering oxygen • Be prepared to provide positive-pressure ventilation if a COPD patient begins to hypoventilate.

25. Infant and Child Considerations • Mouth and nose —smaller • Obstructed more easily • More space taken up by tongue • Lower tidal volumes • More prone to gastric inflation

26. Adequate Breathing • Rhythm • Regular • Irregular • Quality • Breath sounds — present and equal • Chest expansion — adequate and equal • Minimum effort of breathing • Depth (tidal volume) – visible chest rise

27. Adequate Breathing Rate • Adult — 12-20/minute • Child — 15-30/minute • Infant — 25-50/minute

28. Important Terms • Respiratory distress • Respiratory failure • Respiratory arrest

29. Respiratory Distress • Shortness of breath • Agitation or restlessness • Active accessory muscle use • Retractions • Cyanotic skin • Increased pulse rate • Increased respiratory rate

30. Noisy Breathing • Crowing • Audible wheezing • Gurgling • Snoring • Stridor • A harsh sound heard during breathing • Upper airway obstruction

31. Respiratory FailureInadequate Breathing • Depressed mental state (e.g., responsive to voice, responsive to pain, or unresponsive) • Rate – very fast or very slow • Rhythm — irregular • Quality • Breath sounds — diminished or absent • Chest expansion — unequal or inadequate • Depth (tidal volume) — inadequate/shallow • Cyanotic skin color

32. Inadequate Breathing • Rate — outside of normal ranges • Rhythm — irregular • Quality • Breath sounds — diminished or absent • Chest expansion — unequal or inadequate • Increased effort of breathing — use of accessory muscles — predominantly in infants and children • Depth (tidal volume) — inadequate/shallow

33. Respiratory Arrest Definition: Complete cessation of breathing

34. Airway Interventions • Manual techniques • Head tilt/chin lift • Jaw thrust • Mechanical techniques • Oropharyngeal airways • Nasopharyngeal airways • Suctioning

35. Opening the Airway • Head tilt/chin lift • Jaw thrust (if injury to the neck is suspected)

36. Techniques of Suctioning • Body substance isolation • Purpose • Remove blood, liquids, and food particles from the airway • Some units are inadequate for removing solid objects • Suction immediately when a gurgling sound is heard

37. Soft (French) • Useful for suctioning the nasopharynx • When rigid device is not possible • Inserted only as far as the base of the tongue

38. Suctioning Issues • Suction for no more than 15 seconds at a time (less in infants and children). • Secretions that cannot be removed quickly • Log roll, clear manually • If patient produces frothy secretions as rapidly as suctioning can remove: • Suction for 15 seconds • Artificially ventilate for 2 minutes • Suction for 15 seconds • Continue in that manner • Rinse catheter and tubing as needed.

39. Airway Adjuncts and Techniques

40. Oropharyngeal Airway • Measure the airway.

41. Oropharyngeal Airway • Insert airway upside down, with the tip facing the roof of the patient’s mouth. • Rotate device into position. • Alternate method: Hold the tongue down and forward with a tongue depressor and insert airway directly.

42. Nasopharyngeal Airway • Measure from tip of nose to tip of ear. Look at diameter of nostril.

43. Nasopharyngeal Airway Insert airway with bevel toward base of nose or septum.

44. Positive-Pressure Ventilation • Required for patients in respiratory failure and respiratory arrest • Characteristics of effective positive-pressure ventilation • Rate appropriate for age • Adult – One breath every 5-6 seconds • Children and infants – One breath every 3-5 seconds • Chest rise observed with each breath

45. Positive-Pressure Ventilation • Characteristics of effective positive-pressure ventilation (continued) • Each breath delivered slowly • Over 1 to 2 seconds for adults • Over 1 to 1.5 second for children and infants • Oxygen saturation is greater than 93%, if pulse oximeter is used.

46. Positive-Pressure VentilationOrder of Effectiveness • Mouth-to-mask • Two-person bag-valve-mask • Flow-restricted, oxygen-powered ventilation device • One-person bag-valve-mask

47. Mouth-to-Mask • Allows for good seal and for direct feedback to the rescuer

48. Bag-Valve-Mask • Oxygen reservoir • Self-refilling bag • Valve to allow oxygen inlet flow of 15 L/min • Valve to make it nonrebreather • If pop-off valve, ability to disable if necessary when high resistance encountered

49. Bag-Valve-Mask • Bag capacity — approximately 1,600 mL • Single rescuer may have difficulty maintaining an airtight seal. • Result — May provide less volume than mouth-to-mask

50. Bag-Valve-Mask • Select correct mask size (adult, infant or child). • Position thumbs over top half of mask. • Place index and middle fingers over bottom half. • Place apex of mask over bridge of nose. • Lower mask over mouth and upper chin. • If mask has large round cuff, position center port over mouth.