Lesson 05
- 1. Lesson 5 Airway, Oxygenation, and Ventilation
- 2. Objectives As a result of active participation in this lesson you should be able to: Recognize the need for early management of airway, oxygenation, and ventilation in trauma patients Discuss advantages, disadvantages, indications, and contraindications of basic and advanced methods and devices for management of the trauma patient’s airway, oxygenation, and ventilation Discuss the need for on-going assessment of the trauma patient’s airway, oxygenation, and ventilation
- 3. Scenario It is a pleasant spring morning. You and your partner have been dispatched to a residence to assist a man injured by a falling tree. As you approach the residence, a middle-aged man directs you to the back yard where you see two men kneeling next to a third man, who is sitting on the ground, leaning against a large fallen tree.
- 4. Scenario The men had been cutting down a tree damaged in a storm. As the tree fell, the injured man was unable to get out of the way. The trunk of the tree missed him, but he was hit by a large branch and knocked to the ground. His co-workers cut the branch away before your arrival.
- 5. Scenario: Scene Size-Up What are the considerations for scene safety? What are the potential injuries associated with this mechanism?
- 6. Scenario: General Impression The patient is awake with labored ventilations and an increased respiratory rate. One of the co-workers is holding a towel to the patient’s right posterior chest, just below the scapula. There is a moderate amount of blood on the towel and on the patient’s shirt.
- 7. Scenario: Primary Survey Awake, anxious Shallow, labored ventilations; rate faster than normal Skin is cool, radial pulse is rapid
- 8. Scenario: Primary Survey What do the findings suggest? Is there evidence of compromised respiration?
- 9. Scenario: Critical Thinking What is happening to this patient? What else do we need to know from the primary survey?
- 10. Scenario: Primary Survey Breath sounds are decreased on the right side There is an open wound to the right posterior chest External bleeding is controlled No air is entering the wound It appears that a 1-inch (2.5-cm) diameter stick is broken off in the wound
- 11. Respiratory Compromise A state of impaired ventilation and/or oxygenation resulting in inadequate cellular oxygenation to meet metabolic needs Cells have different levels of sensitivity to hypoxia Brain cells begin to die in 4 to 6 minutes without oxygen Organ Tolerance to Ischemia
- 12. Ventilation and Respiration Fick concept Airway, ventilation, oxygenation, and circulation are all needed for respiration to occur
- 13. Ventilation and Respiration Ventilation Adequate movement of air into and out of the lungs Oxygenation Delivery of O 2 to the cells via RBCs
- 14. Ventilation and Respiration Respiration External = ventilation Internal = the use of O 2 by the cells to form ATP for energy and convert lactic acid to H 2 O and CO 2 , which can be eliminated through ventilation
- 15. Respiratory Anatomy and Physiology Upper airway Nose Mouth Pharynx
- 16. Respiratory Pathophysiology Upper airway obstruction Tongue Teeth, bone, soft tissue Blood Vomit Foreign body
- 17. Assessment: Airway Level of consciousness General appearance and level of distress Air movement Breathing Ability to speak Work of breathing Noisy ventilations
- 18. Airway Management: Essential Skills Manual clearing of the airway Manual maneuvers Head-tilt chin-lift Jaw thrust Suction Basic adjuncts Oropharyngeal airway Nasopharyngeal airway
- 19. Airway Management Dual lumen/ nonvisualized airways Combitube Laryngeal mask airway
- 20. Airway Management Endotracheal airways Placement under direct laryngoscopy Pharmacologically assisted intubation Face-to-face intubation Blind nasotracheal placement Digital placement Retrograde intubation
- 21. Airway Management Surgical airways Used in “can’t intubate, can’t ventilate” scenarios Needle cricothyrotomy Surgical cricothyrotomy
- 23. Respiratory Anatomy and Physiology Lower airway Epiglottis Larynx Trachea Bronchi Lungs
- 24. Respiratory Anatomy and Physiology Lower airway Lungs Bronchi Bronchioles Alveoli
- 25. Respiratory Anatomy and Physiology Ventilation Air moves in and out of the lungs Requires Intact conducting airways Intact chest wall Contact between visceral and parietal pleura Intact neurological function Intact diaphragm
- 26. Respiratory Anatomy and Physiology Ventilation Tidal volume × respiratory rate = minute volume
- 27. Respiratory Anatomy and Physiology Average adult tidal volume = 500 mL 150 mL remains in the airway above the level of the alveoli and is not available for gas exchange Adult respiratory rate = 12–20 RR of 14 × 500 mL tidal volume = 7000 mL/minute at rest 4900 mL is available for gas exchange 2100 mL never reaches the alveoli
- 28. Respiratory Anatomy and Physiology Ventilation Hypoventilation = inadequate minute volume Trauma increases need for oxygen delivery and carbon dioxide elimination
- 29. Respiratory Pathophysiology Neurological Traumatic brain injury High spinal cord injury Conducting airways Lacerated or obstructed trachea or bronchi Chest wall Flail chest
- 30. Respiratory Pathophysiology Pleural contact Pneumothorax Open Closed Tension Hemothorax
- 31. Assessment: Ventilation General appearance and level of distress Air movement Depth of ventilation Respiratory rate Evidence of tension pneumothorax Blunt or penetrating trauma to the thorax Chest excursion and symmetry Breath sounds Later: pulse oximetry, end-tidal CO 2 monitoring
- 32. Scenario Our patient’s ventilatory rate is increased to 24 per minute
- 33. Critical Thinking Example Minute volume 300 mL × 24 bpm = 7200 mL/minute
- 34. Critical Thinking However: Only 3600 mL is available for gas exchange Remaining 3600 mL never reaches the alveoli Trauma patients have increased oxygen demands
- 35. Ventilation: Management Needle chest decompression for tension pneumothorax Stabilization of flail segment Pocket mask Bag-valve-mask
- 36. Ventilation: Management Bag-valve device with nonvisualized airway or endotracheal tube Manually triggered (oxygen powered) ventilation device High-pressure oxygen delivery via needle cricothyrotomy (percutaneous transtracheal ventilation)
- 37. Respiratory Pathophysiology Decreased ATP (energy) for cell membrane function Low pH results in release of cellular enzymes that autodigest cells Cellular edema Loss of intravascular volume
- 38. Respiratory Anatomy and Physiology Oxygenation Pulmonary circulation Capillary-alveolar interface
- 39. Respiratory Anatomy and Physiology Capillary-alveolar interface = the respiratory membrane
- 40. Oxygenation: Pathophysiology Impaired pulmonary or systemic circulation Pulmonary embolism Shock Increased distance for gas diffusion across the respiratory membrane Pulmonary contusion Pulmonary edema Inability of RBCs to off-load oxygen Alkalosis CO poisoning
- 41. Oxygenation: Assessment Mechanism General appearance Cyanosis Airway Ventilation Circulatory compromise
- 42. Scenario Recall Mechanism General appearance Increased respiratory rate Decreased tidal volume Increased heart rate Decreased breath sounds
- 43. Scenario: Critical Thinking What is/are the likely cause(s) of the patient’s respiratory compromise? How do you know?
- 44. Assessment: Critical Thinking What factors may affect a patient’s ability to respond to and compensate for respiratory compromise? Age Preexisting medical conditions
- 45. Management: Airway, Ventilation, and Oxygenation Prehospital care providers must address all physical and physiological causes of inadequate cellular respiration Patent airway Adequate Rate and depth of ventilation Inspired oxygen/on-loading Circulation of RBCs Off-loading Elimination of carbon dioxide
- 46. Management: Science Studies have shown a tendency toward patient hyperventilation by prehospital personnel Hyperventilation Increases intrathoracic pressure, which impedes blood return to the heart, reducing cardiac output Reduces CO 2 How are your ventilation techniques?
- 47. Management: Science Endotracheal intubation does not necessarily improve patient survival over the use of BVM ventilations RSI does not necessarily benefit patients
- 48. Management: Airway, Ventilation, and Oxygenation Guiding principles What is the cause of respiratory compromise in this patient? What is the care for this problem? Where/how can the patient get this care? What can be done between now and the time the patient reaches definitive care?
- 49. Guiding principles The best airway management and ventilation technique is the one that provides adequate ventilation and oxygenation with the fewest complications Management: Airway, Ventilation, and Oxygenation
- 50. Compromised oxygenation may be occurring before signs and symptoms are pronounced Proper management improves the oxygenation of RBCs, improves the delivery of RBCs to the tissues, and off-loading of oxygen at the cellular level What is the proper management? Management: Airway, Ventilation, and Oxygenation
- 51. Scenario: Airway What are the patient’s airway needs?
- 52. Scenario: Ventilation Does the patient require assisted ventilations?
- 53. Scenario: Oxygenation What guides the administration of oxygenation for this patient?
- 54. Scenario: Circulation What can be done to improve the patient’s circulation?
- 55. Transport Considerations Transport without delay does not mean “scoop and run.” Anything that can be done to immediately improve cellular oxygenation must be done. How do decisions differ based on transport time?
- 56. Scenario: Secondary Survey After beginning transport you perform a secondary survey Minor lacerations and abrasions to the upper extremities No additional injuries to the chest Breath sounds remain decreased on the right Abdomen is soft and nontender No apparent injuries to the pelvis or lower extremities
- 57. Scenario: Secondary Survey Vital signs RR 28 SaO 2 92% on 15 liters O 2 HR 116 Blood pressure 132/90
- 58. Complications: Inadequate Airway, Ventilation, and Oxygenation Prehospital care can make a difference in the patient’s eventual outcome Failure to maintain the airway and inadequate ventilation and oxygenation lead to tissue hypoxia Overly aggressive ventilation leads to increased intrathoracic pressure, poor preload, and inadequate perfusion
- 59. Minimizing Complications What is the best airway for the patient?
- 60. Scenario: On-going Assessment Breath sounds remain decreased on the right Respiratory rate 28 SaO 2 90% on 15 liters O 2 Heart rate 118 Blood pressure 134/90
- 61. Scenario: Outcome Chest x-ray film confirmed a 70% right pneumothorax A chest tube was inserted in the ED The impaled stick was surgically removed A lacerated bronchus required surgical repair A right pulmonary contusion evolved postoperatively The patient was released when the pulmonary contusion resolved sufficiently to allow adequate oxygenation on room air
- 62. Summary Respiratory compromise is a state of impaired ventilation and/or oxygenation resulting in inadequate cellular oxygenation to meet metabolic needs.
- 63. Summary Prehospital care providers must address all physical and physiological causes of inadequate cellular respiration. How do we do this?
- 64. QUESTIONS?
Editor's Notes
- #6: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, if participants respond with a list of potential injuries, follow up with a questions such as “What makes you say that?” This verifies understanding of the mechanism of injury. Key Points: Primary scene safety consideration is the stability of the tree. The mechanism is suspicious for blunt and penetrating trauma; particularly at the point of impact of the tree branch. Trauma to the spine is possible, as well as injuries to the thoracic and abdominal organs.
- #9: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, if participants respond with an answer of “Yes,” follow up with a question such as “What makes you say that?” This verifies understanding of how the patient’s signs and symptoms relate to ventilatory compromise. Key Points: Assessment is a process of seeking evidence of potential problems, including evidence of impaired respiration. Participants should note the following: The patient is awake and able to speak only 2 to 3 words without a breath. (LOC, airway, breathing) The patient is exhibiting labored ventilations (general impression) Based on the mechanism of injury and general impression, there is ventilatory compromise. External bleeding is minor, but internal bleeding cannot be ruled out and shock is a possibility. Compromised ventilation results in hypoxia and acidosis, which can kill the patient rapidly.
- #10: Key Points: Understanding what is happening to the patient is critical to understanding how respiratory compromise kills and what prehospital care providers must do to intervene in the process. The patient’s airway is patent, but he is having labored ventilations. He has an injury to the chest, therefore we suspect an injury to the chest wall and/or lung or compromised pleural contact are interfering with ventilation. Ventilatory (breathing) assessment is not complete until the chest and lungs have been assessed by inspection, palpation, and auscultation.
- #11: Key Points: Compromises to airway, breathing, and circulation are treated in the primary survey. What does this patient need right now? What else do we need to know? Transition: Discussion of pathophysiology follows.
- #12: Instructor Notes: It is critical that participants understand this basic definition of respiratory compromise. Key Points: The patient’s ventilations are compromised. The patient is working harder to achieve an adequate minute volume. As the patient’s ability to compromise diminishes, his cells will not receive enough oxygen to produce an adequate amount of energy for them to function.
- #13: Key Points: The terms ventilation and respiration are often used interchangeably, but physiologically, they are not the same.
- #14: Key Points: A patent airway is a prerequisite to adequate ventilation. Ventilation does not necessarily result in oxygenation, in and of itself. The air entering the lungs must contain an adequate concentration of oxygen. The oxygen must be able to cross the alveoli and attach to hemoglobin in RBCs. The RBCs must be delivered to the cellular level. The oxygen must be able to disassociate from the hemoglobin at the cellular level.
- #15: Key Points: Lactic acid is a product of cellular metabolism. Without oxygen, it cannot be converted to water and carbon dioxide for elimination, resulting in acidosis. Oxygen is also needed for ATP production. Without sufficient oxygen, ATP is depleted and cells cannot do their work. If oxygen depletion is severe enough, cells die.
- #17: Key Points: The most common cause of airway obstruction is the tongue.
- #18: Key points: An unresponsive patient cannot protect his or her airway. Unresponsiveness may be due to airway obstruction. Airway obstruction may be secondary to unresponsiveness. No air movement will be present with a complete airway obstruction. In a patient with respiratory effort, a partial airway obstruction may result in noisy breathing. Gurgling – liquids Snoring – tongue Stridor – upper airway obstruction Wheezing – lower airway obstruction
- #19: Key Points: A quick inspection should be performed to assess the oropharynx for food, avulsed teeth, or other material that may need to be manually cleared from the airway. Manual maneuvers relieve and prevent airway obstruction caused by the tongue.. With suspected cervical spinal injury, the jaw thrust is used rather than the head-tilt/chin-lift Suction is needed to remove blood, fluid, and vomit from the airway. The airway must be clear before ventilating of the patient begins. Basic adjuncts assist in preventing the tongue from occluding the airway, but do not relieve the need to maintain proper head position. Aspiration of vomit, fluid, or blood and gastric distension are still possible with basic adjuncts — but a good BLS airway is better than a poor ALS airway.
- #20: Key Points: Nonvisualized airways are an EMT-Basic skill in many states. Nonvisualized airways require less skill maintenance and provide better, though not complete, protection of the airway from aspiration and gastric insufflation. Nonvisualized airways do not require hyperextension of the neck for placement. Prolonged attempts at insertion lead to worsening hypoxia.
- #21: Key Points: Intubation has long been considered the gold standard for airway management. Poor initial training (lack of intubation opportunities) and inadequate skill maintenance lead to decreased competence in intubation. Prolonged attempts worsen hypoxia. A good BLS airway is better than a poor ALS airway.
- #22: Key Points: Surgical airways are used only when an adequate airway cannot be established by any other means. Needle cricothyrotomy leads to inadequate exhalation and overinflation of the chest, impairing ventilation and gas exchange. It is an extremely short-term measure. Provides for adequate ventilation; potential for complications, such as false passage and hemorrhage.
- #24: Key Points: Larynx houses the vocal cords. Trachea divides into right and left main stem bronchi at the carina.
- #25: Key Points: Gas exchange occurs only at the alveolar level.
- #26: Key Points: Ventilation is triggered by increasing levels of CO 2 and (secondarily) by decreasing levels of O 2 . When chemoreceptors detect changes in gas levels, nerves conduct impulses to the respiratory center, which sends impulses to the diaphragm and intercostal muscles. When the diaphragm and intercostal muscles contract, the size of the thoracic cavity increases, creating a vacuum by which the adherent pleural layers expand the lung, decreasing pressure inside the lung and allowing air to flow into the lungs. At the end of inspiration, the diaphragm and intercostal muscles relax, making the thoracic cavity smaller, increasing the pressure inside the lungs, and forcing air to flow out of the lungs. However, air will flow from higher to lower pressure through the path of least resistance. An opening in the chest wall that is 2/3 the size of the tracheal diameter will allow air to flow into the thoracic cavity, where it separates the visceral and parietal pleura.
- #28: Key Points: The respiratory dead space includes all the parts of the airway above the alveoli.
- #29: Key Points: Shock and problems with airway, ventilation, and oxygenation compound each other.
- #32: Key points: Severe ventilatory compromise is apparent by the general appearance. Assess for hypoventilation by considering both the volume and rate of breathing. Assist ventilations immediately if needed. Are there immediately life-threatening causes of hypoventilation that can be addressed in the field? Tension pneumothorax Flail chest
- #34: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, if participants respond with an answer of “Yes,” follow up with a question such as “What makes you say that?” This verifies understanding of how the patient’s signs and symptoms relate to ventilatory compromise.
- #35: Key Points: Recall that with normal rate and tidal volume, 4900 mL is available for gas exchange; this patient has only 3600 mL available for gas exchange. An increased rate can compensate for a decreased volume only to a point. Is the patient neurologically capable of ventilation? Are the conducting airways intact? Is the chest wall intact? Are the pleura in contact with each other?
- #38: Key Points: Consequences of anaerobic metabolism include: Dysfunction of cell membranes such that potassium and lactic acid leave the cell and enter the interstitial fluid, resulting in hyperkalemia and acidosis. pH (acidosis) causes the release of cellular enzymes that destroy cells, ultimately resulting in organ damage, organ death, and patient death. The sodium and water enter the cell resulting in cellular edema and loss of intravascular fluid. The low process of anaerobic metabolism must be reversed by ensuring that oxygenated red blood cells reach the capillaries that supply the body’s cells.
- #39: Key Points: Right atrium Right ventricle Pulmonary artery Lungs Capillary-alveolar interface Pulmonary vein Left atrium Left ventricle Systemic circulation
- #40: Key Points: Gas exchange requires an adequate amount of oxygen reaching the alveoli. An adequate number of red blood cells reaching the pulmonary capillaries. A short diffusion distance across the respiratory membrane. Factors that can increase the diffusion distance and decrease gas exchange: Pulmonary contusion Trapped alveolar air (COPD) Pulmonary edema ARDS
- #44: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. This verifies understanding of the cause of respiratory compromise. Key Points: Penetrating trauma is evident; the mechanism also strongly suggests pulmonary contusion due to blunt trauma. Blood from injured pulmonary capillaries enters the interstitial space between the capillaries and the alveoli, increasing the distance for gas exchange. Gas exchange may not be occurring in injured portions of the lung. There is no evidence of flail chest (3 or more adjacent ribs each broken in 2 or more places). The penetrating injury is allowing air from the lung to enter the pleural space and compress the lung tissue, causing atelectasis (collapsed alveoli). At this point, there is no evidence of a tension pneumothorax. Although there is an opening in the chest wall, it is occluded by a foreign body. Air is not entering the wound. Simple pneumothorax is likely; gas exchange is impaired due to atelectasis. There also may be blood from an injured vessel entering the pleural space, which may result in hemothorax. This would both compromise ventilation and result in blood loss that may be significant.
- #45: Key Points: Age: the chemoreceptors in the elderly are less sensitive to decreases in oxygen and increases in carbon dioxide. Respiratory rate may not be increased despite inadequate oxygen delivery to the tissues. Preexisting medical conditions Patients with cardiovascular and pulmonary disease cannot compensate well.
- #47: Key Points: Reduced carbon dioxide levels leads to cerebral vasoconstriction.
- #51: Key Points: Anaerobic metabolism is occurring before signs and symptoms are evident. Management requires definitive treatment of the cause, as well as restoration of tissue perfusion. Airway Ventilation Oxygenation Circulation
- #52: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, ask how a suggested intervention will address the patients needs and/or why that intervention is a better choice than other interventions. This verifies understanding of the need to address the underlying pathophysiology of respiratory compromise with interventions. Key Points: The patient is awake and able to speak. He does not need an airway intervention at this point. Since shock, including shock due to respiratory compromise, is progressive and we cannot definitively treat this patient, the airway warrants on-going assessment.
- #53: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, ask how a suggested intervention will address the patients needs and/or why that intervention is a better choice than other interventions. This verifies understanding of the need to address the underlying pathophysiology of respiratory compromise with interventions. Key Points: The patient’s respiratory rate is 24 We also need to consider the depth of ventilation to determine adequacy of ventilation. The patient’s tidal volume is decreased from normal, but does not yet require assisted ventilations. Once the ventilatory rate exceeds 30, the tidal volume may be inadequate. He does not yet need assistance, but is approaching the point where ventilatory assistance should be considered We cannot definitively treat this patient, therefore the need for ventilatory assistance must be continually assessed
- #54: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, ask how a suggested intervention will address the patients needs and/or why that intervention is a better choice than other interventions. This verifies understanding of the need to address the underlying pathophysiology of respiratory compromise with interventions. Key Points: Anaerobic metabolism occur prior to outward indications This patient is exhibiting signs of compensation, including an increased respiratory rate The increased respiratory rate is an indication of inadequate cellular oxygenation This patient needs oxygen The goal is to maintain an oxygen saturation level of at least 95% The best way to accomplish this is to provide the patient with 12 to 15 liters per minute of oxygen via a non-rebreathing mask
- #55: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, ask how a suggested intervention will address the patients needs and/or why that intervention is a better choice than other interventions. Key Points: The patient’s circulatory status is stable for now, but the mechanism of injury is consistent with the potential for internal hemorrhage and shock. The circulatory status must be monitored through on-going assessment
- #56: Instructor Notes: Solicit responses from participants rather than supply the information yourself. Ask follow-up questions as needed. For example, ask how a suggested intervention will address the patients needs and/or why that intervention is a better choice than other interventions.
- #58: Instructor Notes: Is the patient’s tissue oxygenation adequate?
- #60: Key Points: The best airway management and ventilation technique is the one that provides adequate ventilation and oxygenation with the fewest complications.
- #61: Instructor Notes: Is the patient stable?