1. Copyright © 2006 by Mosby, Inc. Slide 1 Chapter 45 Respiratory Failure

2. Copyright © 2006 by Mosby, Inc. Slide 2 Mechanical Ventilation  Mechanical ventilation may be delivered by:  Endotracheal tube (most common)  Tracheostomy  Face mask  Cuirass-type device

3. Copyright © 2006 by Mosby, Inc. Slide 3 Mechanical Ventilation  Ventilator modes include:  Assist-control (A/C)  Synchronized intermittent mandatory ventilation (SIMV) With or without pressure support (PS) With or without pressure support (PS)  Less commonly used modes include: SIMV alone SIMV alone Inverse-rate ventilation (IRV) Inverse-rate ventilation (IRV) Airway pressure release ventilation (APRV) Airway pressure release ventilation (APRV)

4. Copyright © 2006 by Mosby, Inc. Slide 4 Mechanical Ventilation  The goal of mechanical ventilation is to totally or partially replace the gas exchange function of the lungs—with as few complications as possible

5. Copyright © 2006 by Mosby, Inc. Slide 5 Mechanical Ventilation  The objectives of mechanical ventilation are to:  Improve and maintain alveolar ventilation  To ensure adequate CO 2 and pH homeostasis, oxygenation, and lung inflation  To reduce the work of breathing

6. Copyright © 2006 by Mosby, Inc. Slide 6 Mechanical Ventilation  Achievement of these objectives  Reverses acute respiratory acidosis with hypoxemia Also called acute ventilatory failure with hypoxemia Also called acute ventilatory failure with hypoxemia  Relieves patient discomfort  Reverses or prevents atelectasis  Reverses muscle fatigue  Stabilizes the chest wall  Allows sedation and/or neuromuscular blockade  Decreases systemic or myocardial oxygen consumption

7. Copyright © 2006 by Mosby, Inc. Slide 7 Etiology and Pathogenesis  Four conditions that commonly require mechanical ventilation  Acute respiratory failure (ARF)—74% Also called acute ventilatory failure (AVF) Also called acute ventilatory failure (AVF)  Exacerbation of chronic obstructive pulmonary disease (COPD)—16%  Coma—7%  Neuromuscular disease—3%

8. Copyright © 2006 by Mosby, Inc. Slide 8 Etiology and Pathogenesis  The causes of ARF include the following:  Postoperative complications  Sepsis  Trauma  Pneumonia  Heart failure  ARDS  Aspiration  Others (miscellaneous)

9. Copyright © 2006 by Mosby, Inc. Slide 9 Etiology and Pathogenesis  All of the clinical scenarios described in Chapter 9 may (and do, if left untreated) lead to respiratory failure  It is crucial that the RCP be able to recognize the clinical scenarios caused by:  The six most common anatomic alterations of the lungs (see Chapter 9), and  The respiratory disorders that produce them (see Table 45-1) page 540

10. Copyright © 2006 by Mosby, Inc. Slide 10 Figure 9-7. Atelectasis clinical scenario.

11. Copyright © 2006 by Mosby, Inc. Slide 11 Figure 9-8. Alveolar consolidation clinical scenario.

12. Copyright © 2006 by Mosby, Inc. Slide 12 Figure 9-9. Increased alveolar-capillary membrane thickness clinical scenario.

13. Copyright © 2006 by Mosby, Inc. Slide 13 Figure 9-10. Bronchospasm clinical scenario (e.g., asthma).

14. Copyright © 2006 by Mosby, Inc. Slide 14 Figure 9-11. Excessive bronchial secretions clinical scenario.

15. Copyright © 2006 by Mosby, Inc. Slide 15 Figure 9-12. Distal airway and alveolar weakening clinical scenario.

16. Copyright © 2006 by Mosby, Inc. Slide 16 Box 45-1. Conditions That May Develop in the Hospital and Complicate the Management of Patients Receiving Mechanical Ventilation CCardiovascular events AAcute respiratory distress syndrome PPulmonary embolism/infarction PPneumothorax NNeuropsychiatric complications EElectrolyte and fluid imbalance UUpper airway obstruction MMalnutrition OOxygen toxicity NNonsense data IInfection AAtelectasis

17. Copyright © 2006 by Mosby, Inc. Slide 17 Table 45-1.

18. Copyright © 2006 by Mosby, Inc. Slide 18 Table 45-1., cont.

19. Copyright © 2006 by Mosby, Inc. Slide 19 Overview of the Cardiopulmonary Clinical Manifestations Associated with ACUTE RESPIRATORY FAILURE  At the right side of each of the clinical scenarios (see Figures 9-7 though 9-12) is an overview of the signs and symptoms of the various diseases that, when allowed to proceed to their “worst case scenario,” end in acute respiratory failure  The following are clinical manifestations of acute respiratory failure that are indications for mechanical ventilation

20. Copyright © 2006 by Mosby, Inc. Slide 20 Clinical Manifestations of Acute Respiratory Failure  Somnolence proceeding to coma  An indication of alveolar hypoventilation  Severe and worsening hypoxemia  Excessive work of breathing  Inadequate lung expansion

21. Copyright © 2006 by Mosby, Inc. Slide 21 Clinical Indicators Clinical Indicators  Respiratory acidosis (acute ventilatory failure)   Pa CO 2,  pH,  PaO 2,  Sp O 2  Agitation, tachycardia, pulse >120, A-aO 2,  Pa O 2 /FI O 2,  shunt fraction, venous admixture

22. Copyright © 2006 by Mosby, Inc. Slide 22 Clinical Indicators Clinical Indicators  Dyspnea,  ventilatory effect,  physiologic dead space,  respiratory rate, diaphoresis, use of accessory muscles, abdominal paradox  Atelectasis,  ventilatory capacity,  maximum inspiratory pressure,  maximum voluntary ventilation

23. Copyright © 2006 by Mosby, Inc. Slide 23 The Fifth Protocol— General Management The Fifth Protocol— General Management  Do any contraindications to invasive mechanical ventilation exist?  Patient’s wishes to the contrary  Needless prolongation of the patient’s life

24. Copyright © 2006 by Mosby, Inc. Slide 24 Ventilator Management and Ventilator Weaning Modes  More than 90% of patients requiring ventilatory support in the United States are ventilated with assist/control alone  Or in combination with PS ventilation  Initial tidal volume (V T ) settings  6 to 10 ml/kg ideal body weight  5 to 6 ml/kg for recent “lung protective strategies”

25. Copyright © 2006 by Mosby, Inc. Slide 25 Ventilator Management and Ventilator Weaning Modes  In routine cases, 10 to 12 ml/kg is used routinely  Tidal volumes as great as 16 ml/kg have been used to minimize atelectasis in acute neuromuscular diseases  And initial PEEP setting of 5 cm H 2 O is used in most cases  However, PEEP should not be used in patients with acute brain injury, and cautiously in COPD patients

26. Copyright © 2006 by Mosby, Inc. Slide 26 Ventilator Management and Ventilator Weaning Modes  Except in patients with anoxic brain or myocardial injuries, permissive hypercapnia is allowed  V T and RR are adjusted to achieve the predetermined pH and plateau pressure goals  The inspiratory flow is set above spontaneous breathing patient demand

27. Copyright © 2006 by Mosby, Inc. Slide 27 Ventilator Management and Ventilator Weaning Modes  Use of other protocols  Bronchopulmonary hygiene therapy protocol  Hyperinflation therapy protocol  Aerosolized medication protocol

28. Copyright © 2006 by Mosby, Inc. Slide 28 Disorder: Normal Lung Mechanics —but Patient Has Apnea  Disease characteristics  Normal compliance and airway resistance  Ventilator mode  Volume ventilation in the AC or SIMV mode  Or pressure ventilation—either PRVC or PC  Tidal volume and respiratory rate  10 to 12 ml/kg  6 to 10 bpm 6 to 10 bpm when SIMV mode is used 6 to 10 bpm when SIMV mode is used Table 9-3 Common Ventilatory Management Strategies

29. Copyright © 2006 by Mosby, Inc. Slide 29 Normal Lung Mechanics, cont.  Flow rate  60 to 80 L/min  I:E ratio  1:2  FIO 2  Low to moderate  General goals and/or concerns  Care to ensure plateau pressure of 30 cm H 2 O or less  Smaller tidal volumes (<7 ml/kg) should be avoided because atelectasis can develop Table 9-3 Common Ventilatory Management Strategies, cont.

30. Copyright © 2006 by Mosby, Inc. Slide 30 Disorder: Chronic Obstructive Pulmonary Disease (COPD)  Disease characteristics  High lung compliance and high airway resistance  Ventilator mode  Volume ventilation in the AC or SIMV mode  Or pressure ventilation—either PRVC or PC  Noninvasive positive pressure ventilation (NPPV) is good alternative  Tidal volume and respiratory rate  Good starting point: 10 ml/kg and 10 to 12 bpm  A small tidal volume (5-8 ml/kg) and 8 to 10 bpm with increased flow rates to allow adequate expiratory time Table 9-3 Common Ventilatory Management Strategies, cont.

31. Copyright © 2006 by Mosby, Inc. Slide 31 COPD, cont.  Flow rate  60 L/min  I:E ratio  1:2 or 1:3  FIO 2  Low to moderate  General goals and/or concerns  Air-trapping and auto-PEEP can occur when expiratory time is too short  ↑ Expiratory time to offset auto-PEEP  May ↑ inspiratory flow up to 100 L/min to ↑ expiratory time  May ↓ V T or rate to ↑ expiratory time  Do not overventilate COPD patients with chronically high Pa CO 2 levels Table 9-3 Common Ventilatory Management Strategies, cont.

32. Copyright © 2006 by Mosby, Inc. Slide 32 Disorder: Acute Asthmatic Episode  Disease characteristics  High airway resistance  Ventilator mode  SIMV mode is recommended—to offset air-trapping  Tidal volume and respiratory rate  Good starting point: 8 to 10 ml/kg  Rate of 10 to 12 bpm  When air-trapping is extensive, a lower tidal volume (5-6 ml/kg) and slower rate may be required Table 9-3 Common Ventilatory Management Strategies, cont.

33. Copyright © 2006 by Mosby, Inc. Slide 33 Acute Asthmatic Episode, cont.  Flow rate  60 L/min  I:E ratio  1:2 or 1:3  FIO 2  Start at 100% and titrate downward per SpO 2 and ABGs  General goals and/or concerns  In severe cases, the development of auto-PEEP may be inevitable  With controlled ventilation, a small amount of PEEP to offset auto-PEEP may be cautiously applied Table 9-3 Common Ventilatory Management Strategies, cont.

34. Copyright © 2006 by Mosby, Inc. Slide 34 Disorder: Acute Respiratory Distress Syndrome  Disease characteristics  Diffuse, uneven alveolar injury  Ventilator mode  Volume ventilation in the AC or SIMV mode  Or pressure ventilation—PRVC or PC  Tidal volume and respiratory rate  Typically started at low tidal volumes and higher rates 8 ml/kg and adjusted downward to 6 ml/kg or 4 ml/kg 8 ml/kg and adjusted downward to 6 ml/kg or 4 ml/kg Respiratory rate as high as 35 bpm Respiratory rate as high as 35 bpm Table 9-3 Common Ventilatory Management Strategies, cont.

35. Copyright © 2006 by Mosby, Inc. Slide 35 Acute Respiratory Distress Syndrome, Cont.  Flow rate  60 to 80 L/min  I:E ratio  1:1 or 1:2  Do what is necessary to meet a rapid respiratory rate  FIO 2  Less than 0.6 if possible  General goals and/or concerns  Goal is to limit transpulmonary pressures  30 cm H 2 O of less if possible  PEEP is usually needed to prevent atelectasis  Permissive hypercapnia may be allowed Table 9-3 Common Ventilatory Management Strategies, cont.

36. Copyright © 2006 by Mosby, Inc. Slide 36 Disorder: Postoperative Ventilatory Support  Disease characteristics  Often normal compliance and airway resistance  Ventilator mode  SIMV with pressure support  Or AC volume ventilation  Or pressure ventilation—either PRVC or PC  Tidal volume and respiratory rate  Good starting point: 10 to 12 ml/kg  Rate of 10 to 12 bpm However, larger tidal volumes (12-15 ml/kg) and slower rates (6-10 bpm) may be used to maintain lung volume However, larger tidal volumes (12-15 ml/kg) and slower rates (6-10 bpm) may be used to maintain lung volume Table 9-3 Common Ventilatory Management Strategies, cont.

37. Copyright © 2006 by Mosby, Inc. Slide 37 Postoperative Ventilatory Support, Cont.  Flow rate  60 L/min  I:E ratio  1:2  FIO 2  Low to moderate  General goals and/or concerns  PEEP or CPAP of 3 to 5 cm H 2 O may be applied to offset atelectasis Table 9-3 Common Ventilatory Management Strategies, cont.

38. Copyright © 2006 by Mosby, Inc. Slide 38 Disorder: Neuromuscular Disorder  Disease characteristics  Normal compliance and airway resistance  Ventilator mode  Volume ventilation in the AC or SIMV mode  Or pressure ventilation—either PRVC or PC  Tidal volume and respiratory rate  Good starting point: 12 to 15 ml/kg  Rate of 10 to 12 bpm Table 9-3 Common Ventilatory Management Strategies, cont.

39. Copyright © 2006 by Mosby, Inc. Slide 39 Neuromuscular Disorder, cont.  Flow rate  60 L/min  I:E ratio  1:2  FIO 2  Low to moderate  General goals and/or concerns  PEEP of 3 to 5 cm H 2 O may be applied to offset atelectasis Table 9-3 Common Ventilatory Management Strategies, cont.

40. Copyright © 2006 by Mosby, Inc. Slide 40 Classroom Discussion Case Study: Acute Respiratory Failure