Airway pressure release ventilation (APRV) in PICU: Current evidence. Chor Yek Kee Sarawak General Hospital

Transcription

1 Airway pressure release ventilation (APRV) in PICU: Current evidence Chor Yek Kee Sarawak General Hospital

2 Outline Brief introduction of APRV History of APRV Common confusion in APRV Features of APRV and how it works Evidences of APRV Future of APRV

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4 Natural High Frequency Ventilation

5 Natural APRV Blowhole of dolphin

6 Natural APRV

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9 Intrinsic lung pathology reduced FRC APRV open up lung at FRC Healthy lung at normal FRC ,.,. ; High level CPAP Extrinsic compressing factor reduced FRC APRV maintained FRC by counter extrinsic pressure High level CPAP

10 Constant Vs Intermitent Recruitment Open the lung and keep it open Never let the lung collapse Lachmann B : Intensive Care Medicine 1992 Joshua Satalin : Ann Transl Med 2016

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13 Mode of ventilation Percentage APRV 1.6% Conventional 75.2% HFPV 16.4% Non-invasive 8.5% 59 PICU from North America and Europe, Cross sectional study 2007

14 2013 survey 88 respiratory therapist 4 countries United State Canada Saudi Arabia United Arab Emirates

15 History of APRV

16 APRV is a new way to administer simultaneously a supportive level of CPAP and assist CO2 elimination (1987)

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18 APRV Setting P High P Low T High T Low Pressure during CPAP phase Pressure during release phase Time during CPAP phase Time during Release Phase % CPAP Percent CPAP

19 APRV is a new way to administer simultaneously a supportive level of CPAP and assist CO2 elimination (1987)

20 Tremendous variation in setting of APRV Impossible to assess efficacy of a single strategy since almost none of the APRV setting were identical

21 APRV Strategies Fixed ( F-APRV) Personalised P-APRV T High CPAP < 90% of total cycle time. T Low Fixed T Low, not base on changing of lung mechanic P Low P low is set > 0 cmh2o T High T Low P Low CPAP > 90% of total cycle time T low is set by the changes in the lung mechanic by analysing the slope of the expiratory flow curve P low is set at 0 cmh2o

22 APRV BIPAP Christine and Down et al. Airway Pressure Release Ventilation. CCM 1987 Baum M et al : BIPAP- a new form of augmented ventilation. Anaesthetist : 1989

23 Superficially similar BUT Fundamentally different

24 Inspiratory and Expiratory ratio (I:E ratio) BIPAP APRV > 2 : 1 Extreme inversed ratio FUNCTIONAL FIXED 1 : 1

25 APRV is named in various way and can be set in machine with BIPAP mode 1. APRV ( Dragger Evita, Savina and V series, Hamilton G5 ) 2. Bi-Vent ( Maquet Servo-I ) 3. BiLevel ( Engstrom carestation, Puriton Bennett 840 & 980, Covidien) 4. APRV/BiPhasic ( Viasys Avea ) 5. DuoPAP ( Hamilton )

26 WHY APRV?

27 Features of APRV Elevated CPAP Level Time Pressure Release Spontaneous breathing

28 High Level CPAP in APRV Open the lung and keep it open Prolonged CPAP ( P High )--- recruiting the lung Never let the lung collapse Minimal release duration ( T Low ) preventing lung collapse

29 Pressure-volume curve of the lung during inflation and deflation. Pressure-volume curve of the lung during inflation and deflation. Francesca Facchin, and Eddy Fan Respir Care 2015;60: (c) 2012 by Daedalus Enterprises, Inc. Francesca Facchin, and Eddy Fan Respir Care 2015;60:

30 How does elevated CPAP recruit the lung in APRV?

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32 Pores of Kohn Intra Alveolar communication Fowley and Habashi et al AACN 2001

33 How does high CPAP level changes lung volume? Changing in alveolar volume? changing alveolar numbers

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37 inflate Numbers of alveoli Size of the alveoli Alveoli wall length/ microstrain

38 Mother and Daughter hypothesis Increasing the numbers of ( less strained) alveoli

39 Group C Group B Group A -- Sham Group B -- LTV Group C --APRV Tidal volume 10 ml/kg PEEP 5 cmh2o Rate 12 bpm FiO2 = 21% Low tidal volume group Tidal volume 4 to 6 ml/kg PEEP according to PEEP/FiO2 table APRV with tidal volume of 10 ml/kg

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41 APRV Pressure-volume and Pulmonary curve of the lung during vascular inflation and deflation. resistance Francesca Facchin, and Eddy Fan Respir Care 2015;60: Francesca Facchin, and Eddy Fan Respir Care 2015;60: (c) 2012 by Daedalus Enterprises, Inc.

42 PVR and Safe Zone Correlation

43 Toronto Sick Kid ( 2007 to 2009) Prospective crossover cohort study Recruited 20 patients : 9 TOF and 11 cavo-pulmonary shunt Measure lung perfusion and cardiac output

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46 Elevated CPAP Level Gradually recruit lung to achieve FRC via collateral respiration Reduction of micro-strain to the alveoli that prevent ventilator induced lung injury At FRC, improve pulmonary perfusion and oxygen delivery

47 Features of APRV Elevated CPAP Level Time Pressure Release Spontaneous breathing

48 Intermitent release ( T low ) Setting T PEFR ( EEFR/PEFR ) 50 to 75% with P Low of 0 cmh20 Determine the amount of end expiratory lung volume ( EELV) that is retained. Maintained alveolar stability

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51 Expiratory flow pattern of different pathology with PEEP of 0 cmh2o a - normal lung b - restrictive c - obstructive PEFR = Peak expiratory flow rate EELV = End expiratory lung volume Lung will collapse if expiratory time is too short in restrictive lung e.g. ARDS

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53 More restrictive lung shorter T Low

54 Despite P low is 0 cm H2O Actual tracheal pressure never reach 0 cmh2o (Green line) AutoPEEP which maintain alveolar stability

55 APRV ventilation at T-PEFR 75% There is only 10% of variation of alveolar volume between end inspiration and release phase at injured animal lung model

56 Normal alveoli No stain Alveoli duct and alveoli sac Alveolus

57 Injured rat model

58 Time Pressure Release Titration based on lung mechanic that maintained stability of lung At T-PEFR of 75%, there is significant reduce in conducting airway microstrain

59 Features of APRV Elevated CPAP Level Time Pressure Release Spontaneous breathing

60 Spontaneous breathing at APRV Spontaneous breathing enhance cardiopulmonary and organ perfusion benefit. Spontaneous breathing without pressure support favor gas distribution to dependent area

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62 APRV

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64 Wide variety of APRV setting have all been used in literature making comparison between studies difficult PubMed Search 1987 to 2015 Excluding NIV, review, editorials and case studies (52 articles) 60 Study designs are mainly Cossover Randomized prospective Retrospective case control Retrospective review 28 human studies 32 animal studies

65 1. None of the studies reviewed showed a worse outcome using APRV as compared with CPPV 2. Many studies showing significant benefits in cardiopulmonary variables 3. P-APRV personalized, adaptive mechanical breath may prove more efficacious at treating and preventing ARDS than the current standard of care 4. More studies are needed using consistent and well-defined settings to identify the optimal APRV breath necessary to maximize lung protection

66 Let s see

67 APRV in Neonate

68 APRV in Premature Piglet

69 APRV in Paediatric

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71 Halt the progression of ARDS using APRV?

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73 Systemic review 16 articles 66,199 patients

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75 What is actually happening out there?

76 15 questions survey regarding clinical management strategies with APRV Started January 4, 2016 Total 60 respondent from 60 different hospital. 74% of these hospital use APRV as initial rescue strategy for patient failing conventional ventilator. Respiratory Care June 2017

77 Respiratory Care June 2017, respcare.05494

78 Respiratory Care June 2017, respcare.05494

79 Respiratory Care June 2017, respcare.05494

80 Amato et NEJM 2015

81 Amato et NEJM 2015

82 Conclusion from current evidence 1. Tremendous variation in setting of APRV, most of the study regarding the setting were physiology concept, animal data and small clinical trial 2. Impossible to assess efficacy of a single strategy since almost none of the APRV setting were identical. 3. Studies compare between APRV and CPPV did not show worse outcome but showing significant benefit in cardiopulmonary variables. 4. Personalized APRV (P-APRV) may prove more efficacious at treating and preventing ARDS. 5. APRV reduces sedation and neuromuscular blocker requirements

83 Thank you