1. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Chapter 44 Initiating and Adjusting Invasive Ventilatory Support

2. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.2 Learning Objectives  Discuss the goals of ventilatory support.  Describe how to choose an appropriate ventilator to begin ventilatory support.  Explain how to select an appropriate mode of ventilation given a patient’s specific condition and ventilatory requirements.

3. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.3 Learning Objectives (cont.)  Choose appropriate initial ventilator settings, based on patient assessment.  Describe how to assess a patient after initiation of ventilation.  Explain how to adjust the ventilator on the basis of the patient’s response.

4. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.4 Introduction to Ventilatory Support  Aims to maintain tissue oxygenation and remove CO 2  Supports or replaces normal ventilatory pump  Moves air in and out of lungs, or “ventilates”  Provides sophisticated life support  Initiation requires sound clinical judgment

5. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.5 All of the following are characteristics of ventilatory support, except: A.Increases quality of life B.Helps maintain tissue oxygenation C.Supports or replaces normal ventilatory pump D.Helps in removal of CO 2

6. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.6 Diagnoses Requiring MV  Most common: acute respiratory failure (74%) followed by exacerbation COPD, coma, NMD

7. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.7 Goals of Mechanical Ventilation  Primary goals  Adequate alveolar ventilation (V A )  Maintain tissue oxygenation FIO 2, PEEP, MAP  Restore acid-base balance  Reduce WOB and myocardial work  Provide PEEP/CPAP to recruit lung  Lung protective strategy: Small V T and appropriate PEEP levels Maintain P plat < 30 cm H 2 O

8. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.8 Goals of MV (cont.)

9. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Goals of Mechanical Ventilation 9

10. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.10 Initial Ventilator Setup  Many decisions to make:  Are indications present?  Use noninvasive or invasive ventilation?  Type and method to establish airway?  Pressure or volume ventilation?  Partial or full ventilatory support?  Mode of ventilation?  Select appropriate ventilator settings for mode.  Set appropriate alarm and backup values.

11. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.11 Pressure-Control versus Volume- Control Ventilation  Pressure ventilation  Includes : pressure assist/control (PA/C), SIMV, PRVC, VS, and airway pressure release ventilation (APRV).  Volume ventilation  Essentially include : volume assist/control (VA/C) and synchronized intermittent mandatory ventilation (SIMV).

12. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Controlled Ventilation 12

13. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.13 Full vs. Partial Ventilatory Support  Full support does not require patient work  Patient is either passive or simply triggers the breath to initiate inspiration allowing the ventilator to perform vast majority of work of breathing  Partial support does require patient effort  Implies only a percentage of work of breathing is provided by ventilator. Normally, when partial ventilatory support is indicated SIMV, PSV, VS and PAV or NAVA are modes of choice

14. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.14 A/C Ventilation  Patient-triggered or time-triggered CMV  Typically VC-CMV used (see Box 44-5)  Advantages include Ensured minimum safe level of ventilation Patient can increase rate above that set To ⇓ WOB must ensure sensitivity and flow are set adequate to meet patient needs

15. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.15 Control Ventilation  True control ventilation, patient cannot trigger breath  Should be avoided  Apnea achieved by sedation or paralytics  Advantages  Elimination of WOB (rest-fatigued muscles)  Total control, allows use of inverse I:E ratio  Disadvantages  Need for sedatives and possibly paralytic drugs

16. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.16 All of the following are advantages of assist/control ventilation, except: A.Ensured minimum safe level of ventilation B.Patient can trigger a breath above the set rate C. ⇓ Work of breathing D.Allows full control ventilation

17. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.17 Intermittent Mandatory Ventilation (IMV)  May be used as means of providing partial or full ventilatory support. Modern ventilators use synchronized IMV or SIMV  Volume or pressure ventilation (typically VC)  Machine breaths: time or patient triggered  PSV used to ⇓ WOB for spontaneous breaths  SIMV may delay weaning compared to spontaneous breathing trials or PSV

18. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.18 Intermittent Mandatory Ventilation (IMV) (cont.)

19. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.19 Pressure Support Ventilation (PSV)  Assists spontaneous breaths to set PSV level  Patient triggered, pressure limited, flow cycled  May ⇓ WOB and improve patient–ventilator synchrony

20. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.20 All of the following are characteristics of the SIMV mode, except: A.Used as a means of providing partial or full ventilatory support B.Has better outcomes in the initial phases of ventilatory support than other modes. C.Machine breaths are time triggered D.SIMV may delay weaning compared to PSV

21. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.21 High-Frequency Ventilation  Respiratory rates range from about 3 hertz or 180/min to about 8 hertz or 480/min, and very small V T that may approach anatomic deadspace  Gas transport can occur by  Bulk flow, Taylor dispersion, pendelluft, asymmetric velocity profiles, molecular diffusion  HFV superiority not established  HFJV may work best with large air leaks.  HFO may work best with infant RDS.

22. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.22 Initial Setup VC-A/C or VC-SIMV  V T and RR  Determine V E normally 80–100 ml/kg/min IBW  Initial V T 6–8 ml/kg IBW with RR 12–16 beats/min  V T 4–6 ml/kg IBW for ALI or ARDS  In all patients ⇓ V T as needed to keep P plat <28 cm H 2 O, increase RR to maintain CO 2  See Table 44-7 for suggested initial settings.

23. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.23 Initial Setup: Trigger Sensitivity  Set to least possible while avoiding auto- triggering  Pressure trigger: -0.5 – -1.5 cm H 2 O  Flow trigger is generally more sensitive and should be set at 1 to 2 L/min  Set based on specific ventilator  If leak is present, revert to pressure triggering to avoid autocycling

24. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.24 Initial Setup: Trigger Sensitivity (cont.)

25. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.25 All of the following are factors that can affect trigger sensitivity and prolong ventilator response time, except: A.Low trigger sensitivity B.Auto-Peep C.Increase circuit deadspace D.Increase in patient lung compliance

26. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.26 Inspiratory Flow, Time, and I:E Ratio: Volume Ventilation  Most ventilators allow you to set either flow or I T (I T %), as well as V T, and RR  Whether with flow or I T control adjust to get I T of ~0.6–1.0 s I:E ratio of 1:2 or less The above usually correspond with a peak flow of 40–80 L/min  Adjust flow to meet or exceed patients’ inspiratory flow requirements.  Low flow tends to increase patient WOB.

27. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.27 Inspiratory Flow, Time, and I:E Ratio: Volume Ventilation (cont.)

28. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.28 Flow Waveform  VC breaths flow can be set (ventilator dependent):  PC or PSV breaths are always decelerating  PC with adequate I T, flow reaches zero  PSV flow cycled at preset or adjusted 5%-85% of PF

29. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Flow Waveform 29

30. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.30 Inspiratory Hold or Pause  Use with caution as increases MAP and may impede venous return  Brief hold may improve distribution of ventilation and oxygenation  Other uses  Controversial use with aerosol treatments  I pause 0.5–2 second obtain P plat (to derive C L and R aw )  I pause for inspiratory chest radiograph

31. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.31 An inspiratory hold can be used for all of the following, except: A.To measure CL and Raw B.Assists in use of aerosol treatments C.Decrease MAP D.Used for inspiratory chest x-rays

32. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.32 Oxygen Percentage (F I O 2 )  If unsure, start with 100% O 2  Titrate rapidly on clinical progression and SpO 2  Previous gases, stable patients, diseases responsive to oxygen, start on 50–70% O 2  Postoperative, COPD, emphysema, chronic bronchitis, drug overdose without aspiration, or neuromuscular disease and postoperative patients with normal lungs  Monitor closely, particularly SpO 2, adjust as required

33. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.33 PEEP/CPAP  Initially PEEP 5 cm H 2 O “physiologic”  Higher PEEPs used to improve/maintain FRC and oxygenation  High FIO 2, PaO 2 50–60 mm Hg consider use  To treat: ALI, ARDS, pulmonary edema, etc.  In high FRC conditions may use to offset auto- PEEP and gas trapping.  Try to minimize auto-PEEP.  Ensure that set PEEP does not ⇑ 80% of measured auto-PEEP.

34. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. PEEP/CPAP 34

35. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.35 Open Lung Strategy, Recruitment Maneuvers, & PEEP  ALI/ARDS patients  Start PEEP at 10-15 cm H 2 O. Maintains open lung  PC to target V T 4–8 ml/kg IBW  Increase RR to maintain acceptable PaCO 2 and pH of 7.25–7.35 (permissive hypercapnia but OK pH)  Lung recruitment  Thought to avoid or reduce VILI

36. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.36 Rise Time (Slope) & Alarms  Set rise time to avoid excessive overshoot while meeting patient’s flow requirements  Alarms must be set tight enough to warn of problems without being nuisance.  Pressure limit: VC set 10–15 cm H 2 O > PIP If PIPs too high, can remedy by  ⇓ peak flow or VT  ⇑ I T or changing flow waveform  See Figure 44-15 for summary of initial settings

37. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Pressure Rise Time 37

38. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.38 Adjusting Ventilatory Support  All adjustments are based on patient assessment and clinical data.

39. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.39 Oxygenation Concentration  Target : PaO 2 60–80 mm Hg, SaO 2 >90%  Simple formula to determine O 2 needs: Initial (PaO 2 /FIO 2 ) = Desired (PaO 2 /FIO 2 )  100% in initial patient settings, titrated in decrements of 20% or less  Once the desired PaO 2 and saturation are reached, decrements of 5–10%  Titrate using ABGs or pulse oximetry or both.

40. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Oxygen Concentration 40

41. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.41 PEEP/CPAP  Minimum PEEP (popular)  Least PEEP to achieve adequate oxygenation PaO 2  60 mm Hg on FIO 2 < 0.6  Optimal PEEP based on O 2 delivery (DO 2 )  DO 2 = Q T  CaO 2 (Q T = cardiac output)  PEEP is increased by 2 cm H 2 O until DO 2 ⇓ Best PEEP exceeded go back 2 cm H 2 O Note Table 44-10 for an example of determining optimal PEEP.

42. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.42 PEEP/CPAP  Compliance-titrated PEEP  C ST will increase with increased PEEP until overdistention occurs (see Table 44-10). Use with caution- cardiac compromise may occur prior to overdistention  PEEP titrated with PV curves  Static or slow curves may identify LIP PEEP adjusted to 2 cm H 2 O above LIP  See Figure 44-11

43. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. PEEP/CPAP 43

44. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.44 Which of the following is true about determining oxygen concentration? A.Target : PaO 2 180–200 mm Hg, SaO 2 =100% B.Simple formula to determine O 2 needs: Initial (PaO 2 /FIO 2 ) = Desired (PaO 2 /FIO 2 ) C.21% in initial patient settings, increase in increments of 20% or less D.Once the desired Pao 2 and saturation are reached, increase in increments of 5–10%

45. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.45 PEEP Tables  ARDSnet study FIO 2 -PEEP table (see Box 44-8)  FIO 2 -PEEP settings adjusted together to obtain adequate oxygenation PaO 2 60–80 mm Hg, SpO 2 >90%

46. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.46 Other Oxygenation Techniques  Bronchial hygiene  Sitting patient up, getting out of bed, walking  30–45º elevation of head reduces risk of VAP  Postural drainage, adequate humidification, and bronchodilator therapy may be beneficial

47. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.47 Other Oxygenation Techniques  Prone positioning  May improve PaO 2 and decrease shunt fraction  May reduce mortality in severe ARDS if used early  Mechanism may be In ARDS, dorsal lung injury  Supine: most gas and blood flow to dorsal injured areas, so shunt increases  Proning: most gas and blood to dependent areas where healthy lung tissue is so better ventilation and perfusion matching  Serious complications, use cautiously

48. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.48 Ventilation  Alveolar ventilation is determined by RR, V T, and deadspace (V Dphys ), described by: V A = (V T – V Dphys )RR  Adequacy of V A is best assessed by PaCO 2 ; if PaCO 2 rises, V A is inadequate and vice versa PaCO 2 = (0.863  VCO 2 )/V A  Ventilator adjustments to V A can predict changes in CO 2........

49. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.49 Ventilator Adjustments to Alter PaCO 2  Rate change only, with no change in VCO 2 or V Dphys : Initial PaCO 2(1)  f (1) = Desired PaCO 2(2)  f (2)  V T change only, with no change in VCO 2 or V Dphys : Initial PaCO 2(1)  V T(1) = Desired PaCO 2(2)  V T(2)..

50. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. Ventilator Adjustments to Alter PaCO 2  Adding 6 inches mechanical deadspace generally adds 2–3 mm Hg PaCO 2  All above predictions probably will not be met if the patient alters their breathing pattern (V T or f). 50

51. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.51 Adjusting Tidal Volume & Rate  V T specific to patient condition, with a P plat <28 cm H 2 O  Larger V T set for patients with normal lungs  Smaller V T set for patients with ALI/ARDS

52. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.52 Adjusting Rate in Apneic Patient  Precise control of PaCO 2 can be achieved  Formula predicts what RR adjustment affects will be on PaCO 2, with no change in VCO 2 or V Dphys : Initial Desired PaCO 2(1)  f (1) = PaCO 2(2)  f (2)  Patient’s RR is 18 beats/min, PaCO 2 is 50 mm Hg. If a PaCO 2 of 40 were desired, the RR be set at what value? 50  18 = 40  f (2) = Adjust rate to 22 or 23 beats/min.

53. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.53 Which of the following is appropriate for determining patient settings on volume control ventilation? A.VT specific to patient condition, with a P plat greater than 28 cm H 2 O B.Smaller VT set for patients with normal lungs C.Larger VT set for patients with ALI/ARDS D.Initial VT for patient with normal lungs should be 6-8 mL/kg

54. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.54 Adjusting V T in Apneic Patient  If V T is altered, it changes PaCO 2 predictably.  V T change only, with a constant VCO 2 and V Dphys : Initial Desired PaCO 2(1)  V T(1) = PaCO 2(2)  V T(2)  80-kg (IBW) patient has V T 600 ml and PaCO 2 of 30 mm Hg, but the desired PaCO 2 is 40 mm Hg 30  600 = 40  V T(2) = 450 ml.

55. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.55 Control of Pa CO 2 in SIMV  Select appropriate V T based on patient’s IBW and condition; for most patients, 6–8 ml/kg IBW.  PSV adjusted to minimize WOB for spontaneous breaths  Eliminate accessory muscle use and retractions  Once appropriate V T and PSV levels are set, use SIMV rate control to adjust PaCO 2

56. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.56  Select appropriate V T based on patient’s IBW and condition; for most patients, 8–10 ml/kg IBW.  Set rate to ensure safe minimum level of ventilation  Patient with intact respiratory drive will trigger the ventilator at a rate that sets an appropriate PaCO 2  Patient may hyperventilate by setting a very rapid rate  Caused by pain, anxiety, need for suction, etc.  Correct underlying problem; use sedation and analgesics with care A/C Mode Volume Ventilation & PaCO 2

57. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.57 PCV & PaCO 2  PaCO 2 can be adjusted by PC level or RR  Increasing PC level increases the delivered V T which reduces PaCO 2 Be careful to keep pressure <28 cm H 2 O.  RR is more often increased to reduce PaCO 2. If I T is held constant, V T will be constant If I T % or I:E ratio are held constant, the I T will decrease, which may decrease V T, so be careful.  Easy to see if V T has been affected by looking at the graphics package (see Figure 44-13).

58. Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. PCV & PaCO 2 58