1. Prevention and Treatment of Ventilator-Induced Lung Injury with
HFJV
Watch this space for explanations of at least some of the slides. If you are viewing this as a web page, you may use your left mouse button to actuate animation.
Dawn Rost BS, RRT-NPS
Clinical Specialist
Bunnell Inc.

2. Objectives What is Jet Ventilation, What makes it Unique?
When and Why does it work Better Than other Modes of Ventilation?
How can you Apply HFJV most Effectively?

3. High Frequency Ventilator
LifePulse
High Frequency Ventilator
“The Jet”
Bunnell Hotline

4. “WhisperJet” Patient Box
Here is a picture of our new Patient Box. Its primary feature is that it is very quiet.
I’m very quiet…

5. HFJV in Tandem with CMV Ventilation Oxygenation PEEP Jet CMV
LifePort adapter

6. Jet Ventitlation
The LifePulse is Pressure-Limited, Time-Cycled, like most simple conventional ventilators
The LifePulse becomes a Jet Ventilator once Flow Reaches the LifePort ETT Adapter
The Jet delivers Small VTs at Rapid Rates via jet nozzle Utilizing the Bernoulli Principle

7. “LifePort” ETT Adapter
Pressure Monitoring Line
15-mm Connector
Jet Injection Port
Jet Port Cap
ET Tube Connector
The second key to reducing tidal volumes is the Jet nozzle contained in our little ET tube adapters. The LifePort allows the Jet to be used with conventional ET tubes.

8. LifePort Adapter
Pressure
Monitoring
Port
Jet
Port
Inspired gas is injected down the ETT in high velocity spurts
PIP is measured here and filtered to estimate PIP at the tip of ETT
The PIP measured by the LifePort adapter is filtered to produce the same PIP that one would measure at the distal tip of a Hi-Lo Jet ET tube.

9. VT = 1 mL/kg VD = 2 mL/kg Flow Streaming
They swirl down the airways, splitting at bifurcations, always seeking the path
of least resistance in the center of the airways.
CO2
The Patient Box and LifePort adapter create flow streaming in the airways. We still have convection and diffusion just like we have during normal breathing and conventional ventilation. The convective element of the process is just using much smaller tidal volumes delivered at correspondingly higher rates, and diffusion is enhanced by almost continuously moving higher PO2 gas closer to the alveoli.
VT = 1 mL/kg
VD = 2 mL/kg

10. Flow Streaming Maintaining a Brief I-time :
Ensures that VT Remains Independent of Rate
Enables longer Expiratory Times
Makes Distribution of Ventilation Dependent on RAW
These are the most important differences between the two HFV modalities. What guidance can we gain from focusing on the differences between HFJV and HFOV.

11. HFJV Inhalation and Exhalation
The path of least resistance for exhaled gas is around the inhalation gas streaming in, along airway walls.
CO2
This flow pattern moves secretions towards ETT.
The Patient Box and LifePort adapter create flow streaming in the airways. We still have convection and diffusion just like we have during normal breathing and conventional ventilation. The convective element of the process is just using much smaller tidal volumes delivered at correspondingly higher rates, and diffusion is enhanced by almost continuously moving higher PO2 gas closer to the alveoli.

12. Servo Pressure Servo Pressure is the Driving Pressure for HFJV
It is Feedback Controlled by the Jets Micro-Processor to Adjust Gas Flow
Monitored PIP is Maintained at Set PIP

13. Servo Pressure = driving pressure that provides Flow
Understanding Servo Pressure
Servo Pressure = driving pressure that provides Flow
Servo pressure changes as lung volume changes
Servo Pressure Increases
Servo Pressure Decreases
Volume Increases
Volume Decreases
Servo pressure changes = early warning of patient changes.
Rising Servo Pressure is usually good news. Falling Servo Pressure is always bad news, or at least something that must be attended to such as suctioning.
INCREASES
DECREASES
Improved compliance
Worsened compliance
and/or resistance (bronchospasm)
and/or resistance
Tension pneumothorax
Increased airleak
Tubing leaks
Patient needs suctioning

14. HFJV: Easy to Use The Jet has only 3 controls TI PIP Rate
Usually held Constant at Minimum of .020 seconds
PIP
Rate
PIP & Rate Control Minute Volume & PCO2

15. Conventional Ventilator Role
CMV’s affect on PO2 is limited to:
Utilization of 0 – 10 bpm, Depending upon the Need for Alveolar Recruitment, and
Raising the PEEP to Maintain MAP for Proper Lung Volume and Alveolar Stability

16. Alveolar Recruitment & PaO2
PIP
PEEP
I-time
.020
Rate
420 CV
HFJV
CPAP 4 20
no sustained recruitment
Lung
Volume
Recruitment only happens when enough PEEP is used as Dr. Allison Froese demonstrated for us with her experiments using bunnies in a body box. The rabbits underwent saline lavage to create the model for RDS. When ventilated with the Jet post-lavage, the Jet’s small tidal volumes could be seen on the plethysmograph’s strip chart, but there was no sustained recruitment of lung volume when the conventional ventilator was in CPAP at 4 cm H2O. On 100% oxygen, we could only get a PaO2 of 50 torr.
PaO2 < 50
time

17. Recruiting with Inadequate PEEPV
PIP
PEEP
I-time
.020
Rate
420 CV
HFJV 3
2.0 4 20 30
PEEP is too low!
no sustained recruitment
Then Dr. Froese demonstrated that IMV breaths alone also cannot affect alveolar recruitment when she set the conventional ventilator to deliver long (2-sec I-time), big (PIP = 30 cm H2O) breaths when she pressed the manual breath button. The temporary recruitment afforded by the big breaths could not be sustained at a PEEP of 4.
Time

18. Lung Injury occurs at both ends of the P/V curve
Critical Opening Pressure
Critical Closing Pressure
Over time, babies will experience some degree of lung injury if you are unable to wean.
Increasing PIP to address a high PaCO2 will increase further the risk of lung injury.
HFJV may be indicated.

19. Recruiting Lung Volume with IMV Breaths
HFJV CV
Rate
420 6
PIP 20 20
Higher PEEP
enables recruitment!
PEEP 8 8
I-time
.020
0.4 VL
gradual recruitment
Now, see what happened when Dr. Froese raised the PEEP to 8 cm H2O and set more typical background IMV at 5-10 bpm using the same PIP as the Jet was using. It only took a few minutes before the strip chart from the body box illustrated full lung volume recruitment. The rabbit’s PaO2 went from 50 to 500 torr after only ten minutes on these settings.
Time

20. What a difference adequate PEEP makes!
Low Optimal V
Lung
time V
Again, the X-Y recorder illustrates why we achieved success using higher PEEP. The lung maintained a higher and higher FRD when the PEEP kept the lungs above the critical closing pressure of the alveoli.
Now, there is a trap here: what do you do when you achieve success like this in the NICU? What typically happens when you make a ventilator change, and the patient suddenly improves? Doesn’t someone at the bedside say: “Oh, the baby likes these settings! Let’s just leave the ventilators on these settings for now…” ? 4 8 30 P

21. CMV Limitations
CMV (“Sigh” breaths) are most useful for alveolar recruitment, but contra-indicated when airleaks are present
Once oxygenation improves, sigh breaths should be discontinued because they increase the risk of causing airleaks

22. Rate PIP TI PEEP
CMV:
HFJV:

23. HFJV vs. CV vs. HFOV
One has to understand how lungs work, as well as how HFJV works, to appreciate and predict why HFJV works when other approaches don’t
These are the most important differences between the two HFV modalities. What guidance can we gain from focusing on the differences between HFJV and HFOV.

24. Ventilating Premature Lungs
Distal airway rather than primitive alveolus are the most compliant part of the respiratory tract.
Distal airway disruption :
PIE
Pneumothorax
other bad stuff

25. What we would like to happen:
Ventilating Premature Lungs
What really happens:
What we would like to happen:

26. PRESSURE WAVEFORM COMPARISON20 15 CV
Tracheal Pressure
cm H2O 10
HFOV 5
HFJV
0.2
0.4
0.6
0.8
seconds
Time
MAP

27. CHOKE POINTS may develop when:
airways lack structural strength
the chest is squeezed
gas is sucked out of the airway
Active exhalation promotes gas trapping by creating choke points..

28. Back-pressure (higher PEEP/Paw) splints airways open, allowing gas to enter and exit.+
Paw
One has to use higher PEEP or mean airway pressure to mitigate the airway collapsing effect of active exhalation even in normal lungs.

29. Consequences of Active Exhalation
There is a limit to how much Paw can be reduced without causing gas trapping.

30. Consequences of Passive Exhalation
There is a limit to how fast you can ventilate without causing gas trapping. Remember I:E

31. HFJV Rate I : E 600 bpm 1 : 4 420 bpm 1 : 6 360 bpm 1 : 7
When else would lowering I:E ratio would be helpful/ What disease process? PIE
HFOV is fixed at 33% inspiratory time or 1:2 I:E

32. HFJV vs. CV vs. HFOV Consider the injured lung…
These are the most important differences between the two HFV modalities. What guidance can we gain from focusing on the differences between HFJV and HFOV.

33. Pulmonary Interstitial Emphysema
Restrictive Lung Disorder
Tension PIE restricts
alveolar expansion.
Interstitial gas
increases airway
resistance upstream
from leak site.
The pathophysiology of PIE is perfect for treatment with HFJV, because of the airway restriction that occurs upstream of the site of injury.

34. NON-HOMOGENEOUS LUNG DISEASE
PIE
RDS
High airway resistance limits Jet ventilation
of injured regions.
Atelectatic areas with more patent airways get more Jet ventilation.
Raw Problem
When the high-velocity HFJV breaths are delivered to lungs with PIE, the high velocity tidal volumes will not penetrate into the injured parts of the lungs because airway resistance there is too high. By default, the HFJV breaths will preferentially go where there is lower airway resistance, which in the case of premature infants will be where RDS is more of a problem. This is the perfect way to distribute gas in such lungs, where we want to avoid ventilating the damaged part of the lungs, and we want more gas to go towards areas that are under inflated.
C L Problem
With HFJV: less gas to PIE areas, more gas to RDS areas.

35. “In CV, nearly 100% of set PIP reached the distal airways”
Comparison of HFV and CV in Mechanical Ventilation of a Neonatal Heterogeneous Lung Disease Model  Hills SR, Bunnell JB  Department of Bioengineering, University of Utah and Bunnell Inc, Salt Lake City, UT, USA Snowbird 2008
“In CV, nearly 100% of set PIP reached the distal airways”

36. All Sensors Pressure Sensor
Honeywell AWM43600V
Flow Sensor
All Sensors Pressure Sensor
This is a schematic diagram of the lung model to show the placement of the flow and pressure sensors, the number of generations in the model etc.
7 bifurcation generations and 8 airway generations.

37. Heterogeneous Lung Model
This is the model we developed to mimic the extremes of airway resistances in the lungs of a premature baby with PIE.

38. Gas Distribution in Heterogeneous Lung Model
Peak Pressures (cmH2O)
Peak Flows
(SLPM)
Airway Caliber:
Large
Small
CMV
PIP=35 35 33
0.54
0.51
HFJV 19
9.9
3.91
0.59
Bunnell LifePulse; rate=420bpm, I-time=0.02sec
CV (Bear Cub BP2001; rate=50bpm, I-time=0.4sec) using peak inspiratory pressures (PIP) of 35 with positive end expiratory pressures (PEEP) of 5 cmH2O.

39. Minute Volumes (mL/min)
Gas Distribution in Heterogeneous Lung Model
Tidal Volumes (mL)
Minute Volumes (mL/min)
Airway Caliber:
Large
Small
CMV
PIP=35
4.2
3.9
210
194
HFJV
1.2
0.4
524
185
Volumes through larger tubes ~ 3x those through smaller tubes.

40. PIE Study Conclusions
HFJV leads to the resolution of PIE more frequently than does CV
HFJV results in more rapid improvement of PIE than does CV
HFJV provides better gas exchange at lower airway pressures compared to CV
HFJV does not increase the incidence of important complications
HFJV improves survival in babies with PIE
Given physics of Jet ventilation and the pathophysiology of PIE, one would expect good results from a randomized controlled study, and that is exactly what happened in the latter half of the 1980s. Had we known how to manage PEEP better in those days, the results would have been even better.
(Keszler M, Donn SM, Bucciarelli RL, et al., 1991)

41. Common Jet Applications
Non-Homogenous Lung Disorders:
RDS complicated by PIE, PTX, etc.
Meconium aspiration and other pneumonias (excessive secretions)
ARDS / Acute lung injury in PICUs
BPD / Chronic Lung Disease in NICUs

42. Other Jet Applications
Respiratory failure with hemodynamic compromise (PPHN, cardiac anomalies, etc.)
Congenital Diaphragmatic Hernia and Pulmonary Hypoplasia

43. Nitric Oxide Delivery with the Jet
iNO Vent
Jet CV
"T" into
GAS OUT
tubing
To insert iNO adapters, cut green Jet tubing here and here.
" T " in iNO Vent flow
sensor / delivery system
LifePort adapter
" T "
connector
Sampling line to analyzer

44. Eric Coates, MD Neonatology Fellow
Short Term Outcomes of Near Term Neonates with Pulmonary Hypertension Treated with Inhaled Nitric Oxide and either High Frequency Oscillatory Ventilation or High Frequency Jet Ventilation
Eric Coates, MD
Neonatology Fellow
J Perinatol Jun 26. EPUB

45. Brenner Children’s Hospital (BCH)

46. Primary Outcomes: HFOV/iNO v. HFJV/iNO

47. Multivariate Analysis: Need for ECMO
Odds Ratio
95% CI
HFOV/iNO v. HFJV/iNO
12.5
a/A Oxygen Ratio ≥ 0.1
0.08
12 fold greater risk of needing ECMO if
HFOV/iNO BCH compared to if
HFJV/iNO used when controlling for a/A oxygen ratio

48. Summary
Patients treated with HFJV/iNO at BCH were less likely to need ECMO, even after controlling for a/A oxygen ratio at baseline

49. Limitations Small sample size Single institution
Retrospective data collection
Missing data points
Differences in severity of illness
Unidentifiable changes in care over the 2 epochs

50. Users Guide to Optimizing HFJV
7 Steps to Success
Users Guide to Optimizing HFJV

51. Lung Protective Ventilation* with HFJV
Recruitment
IMV from Conventional Vent
Positive End-Expiratory (PEEP) & Mean Airway Pressure (MAP)
Stabilization
Protection
HFJV – Most Gentle Ventilation

52. #1 Step to Success “Plan Ahead”
When will you start HFJV?

53. #1: Start Early When everything else has failed? When HFOV has failed?
When “Lung Protective CMV” has failed?
When NCPAP has failed?

54. Utah Valley MC Criteria*
Whenever PIE or other air leaks appear
Whenever excessive secretions (pneumonias, MAS) appear
Whenever ventilated patients have cardiac output problems
Whenever HFOV fails (i.e., when RDS starts evolving into CLD)
* 1990

55. #2 Step to Success “Start HFJV with Rational Settings”
Choose an HFJV Rate to Match Patient Size and Condition

56. The Smaller and stiffer the Lungs, the Faster You Can Go
Higher HFJV Rates
The Smaller and stiffer the Lungs, the Faster You Can Go

57. Lowering HFJV Rates Lowering Jet Rate Lengthens E-Time
Ti is remains set at .02 seconds
Remember that Exhalation is Occurring through Obstructed Airways
May Encourage Spontaneous Breathing
May Hasten Extubation

58. HFJV Rate I : E
600 bpm : 4
: 6
: 7
: 9
: 12
When else would lowering I:E ratio would be helpful/ What disease process? PIE

59. BPD / Pulmonary Hyperinflation
Consider a model alveolus sur-rounded by interstitial emphysema.
Where is the gas trapped?
Will lowering PEEP help?
Or will it just make matters worse?
Try using no IMV, moderate PEEP, and low HFJV rate.

60. HFJV for Chronic Lung Disease
Children’s of LA Retrospective Study*:
10 Infants with CLD & Pneumonia/Sepsis, > 4 weeks old, on 100% O2 and HFOV
* Friedlich et al, J. Maternal-Fetal & Neonatal Medicine 2003; 13:

61. HFJV after HFOV for CLD Hrs on HFJV - 1 2 9 24 FiO2 0.97 0.81 0.62
0.54
MAP 14 11
9.3
9.0
O.I.* 29 18 10
9/10 survived and discharged on O2 .
* O.I. = MAP x %O2 / PO2

62. #3 Step to Success “Make a commitment to MAP!”
Preserve existing lung volume & oxygenation by not allowing MAP to fall at HFJV initiation

63. Monitor CMV with Jet in Standby Mode
Active
PIP PEEP
PIP PEEP
MAP
MAP
PEEP
LifePort adapter

64. Don’t let the MAP fall when initiating HFJV !!
MAP and HFJV
Don’t let the MAP fall when initiating HFJV !! CV
HFJV = Gentle Ventilation
MAP
PEEP
You must raise PEEP to maintain MAP for Stabilization / Oxygenation.
Pressure swings from Jet
Whether coming from CV of HFOV, take note of the monitored MAP from the HFJV prior to start-up and match.
Increase PEEP to match.
Time

65. Monitoring HFOV with the Jet
Jet in Standby Mode
PIP
PEEP
MAP
LifePort adapter

66. Monitoring Manual Ventilation with the Jet
Jet in Standby Mode
PIP
PEEP
MAP
LifePort
ETT adapter

67. Adjust HFJV PIP to manage PaCO2
#4 Step to Success
Adjust HFJV PIP to manage PaCO2

68. ∆P (PIP - PEEP) creates VT
HFJV Controls PaCO2
∆P (PIP - PEEP) creates VT 2
VCO2
≈ f x VT
HFJV VT ≈ 1 mL/Kg
≈ 10x smaller than CMV VTs

69. #5 Step to Success “Find & Set Optimal PEEP”
Use CMV “sigh” breaths to find optimal PEEP

70. General Rules: CMV breaths recruit; PEEP stabilizes
Push CMV => CPAP mode whenever SaO2 is stable
Any time SaO2 drops when you lower CMV rate, MAP is too low; so raise PEEP!

71. Find & Set Optimal PEEP V P
Start HFJV, lower CV rate to 5, and keep alveoli from collapsing by maintaining MAP with increased PEEP :
Assume you’re using CV with PEEP = 5, MAP = 9: 8
MAP 9
Maintain HFJV at this PEEP level, weaning FiO2 to maintain target SaO2 until FiO2 ~ 30%.
Then switch CV to CPAP mode to test PEEP.
Maintain CV = 5 bpm
& adjust FiO2 to stabilize SaO2 at 90%.
Does SaO2 fall when 5 IMV breaths CPAP?
If SaO2 falls, increase PEEP as necessary to keep SaO2 stable with HFJV + CPAP. V
PEEP 5 7 25 P

72. #6 Step to Success “Stay on Track”
Monitor Servo Pressure,
Pulse Oximetry, and
Transcutaneous PCO2
Be patient!

73. Monitor Servo Pressure
If S.P. you may need to wean PIP
to keep PaCO2 and pH in target range
If S.P. you may need to suction, re-position ETT, or treat bronchospasms or pneumothoraces……
If ever in doubt, call us: HFJV, available 24/7/365

74. #7 Step to Success “Don’t bail out early!”
Wean to nasal CPAP

75. As oxygenation improves:
Wean big breaths first
(Get CV into CPAP mode)
Wean FiO2 before PEEP/MAP

76. As ventilation improves
Reduce HFJV PIP first
Reduce HFJV Rate to encourage spontaneous breathing

77. More time
for
exhalation
HFJV Rate
I:E Ratio
600 bpm
1 : 4
420
1 : 6
360
1 : 7
300
1 : 9
When else would lowering I:E ratio would be helpful/ What disease process? PIE
240
1 : 12
Patient is on CPAP
> 90% of the time!

78. It’s time to extubate when…
Patient is breathing spontaneously.
HFJV PIP < 15, PEEP < 8, FiO2 < 0.3 20
Set Nasal CPAP = HFJV MAP P 15
cm H2O 10 5
0.0
0.5
1.0
1.5
2.0
Time, seconds

79. *Society of Critical Care Medicine
Mantra of SCCM*
Learn It
32 years of research
90,000 infants
HFJV
Improve It
Deliver It
24 years of clinical applications
How we deliver it
has improved dramatically over all these years!
Measure It
*Society of Critical Care Medicine

80. HFJV works especially well:
to prevent lung injury
to treat airleaks & other lung injuries
to treat non-homogeneous lung disease
to clear excessive airway secretions (MAS)
when respiratory failure is accompanied by hemodynamic problems (PPHN, CDH, cardiac anomalies, post cardiac surgery, etc.)

81. Critical Closing Pressure
Reacting appropriately to Servo Pressure changes will enable continuous Lung Protective HFJV.
Critical Closing Pressure
Gentle, open-lung, lung-protective ventilation … V P

82. Bunnell Inc. HOTLINE 800-800-4358 Website www.bunl.com
Remember KISS-
KEEP IT SIMPLE SILLY