The Quest for Optimal Mechanical Ventilation or Scientific Rationale for HFJV and Its Application Strategies

J. Bert Bunnell, ScD Bunnell Inc. & University of Utah

Personal Disclosure

I have a vested interest in Bunnell Inc., and my pride is very dependent on the acceptance of HFJV, so I am biased.

You should be skeptical of everything I say!

Outline & Objectives

Explain High Frequency Ventilation (HFV) • how and why it works • how HFJV differs from HFOV • how specific HFV device characteristics determine potential success in treating patients with various pathophysiologies.

Outline & Objectives

Discuss scientific basis for strategies to treat various cardiopulmonary pathophysiologies such as RDS, pneumonia, CDH, PPHN, and cardiac anomalies where

prevention

of lung injury is paramount.

Outline & Objectives

Discuss scientific basis for strategies to treat the various pulmonary pathophysiologies such as airleaks (PIE, PTX, BPF, etc.), MAS, bronchiolitis, and chest trauma with HFJV vs HFOV and CMV, where

treatment

of lung injury is necessary.

Outline & Objectives

Questions are welcome any time . . .

My Background

I am a biomedical engineer with degrees in chemical engineering and clinical training in neonatology and pediatric pulmonology.

I witnessed how mechanical ventilation damages premature lungs from the earliest days of mechanical ventilation (1970s).

Goals of mechanical ventilation: 1. Assist ventilation without causing lung injury (aka, prevention).

2. Treating lung injury when it occurs (aka, rescue).

3. Facilitate adequate oxygenation while avoiding hyperventilation unless indicated (e.g., for better pulmonary perfusion in cardiac cases).

Assumptions for preventing lung injury*: avoid

volutrauma

by using smallest V T avoid

barotrauma

by using minimal ∆P avoid

atelectrauma

by keeping the lungs open (maintaining appropriate FRC) avoid inflammatory

biotrauma

by minimizing mechanical and oxidative stress * Arthur S. Slutsky, Lung Injury Caused by Mechanical Ventilation,

Chest.

1999;116:9S-15S.

Lung Protective Ventilation

Recruitment Stabilization Protection Get alveoli open Keep them open Ventilate as gently as possible

Lung Protective Ventilation

Recruitment Stabilization Protection Get alveoli open Keep them open CMV with appropriate PEEP Ventilate as gently as possible HFV Minimize V T and PIP

Loudspeaker = Constant Volume Generator R aw = min. ∆P / V • Minimum Pressure Forced Oscillations (Dubois) ~ 8 Hz in Adults Increasing frequency

This phenomenon indicates that: 1. We might be able to ventilate patients independent of C L , which would most helpful for treating RDS.

2. R AW is the primary factor affecting HFV delivery, which we can use to our advantage in treating lung injury.

Reducing the Volume-Cost of Ventilation 12 10 Conventional Ventilation 8 6 4 Constant Minute Volume (theoretical; zero deadspace) HFPPV

anatomic deadspace

2 0 30 60 90 120 180 240 300 360 420 480 540 600 Frequency (bpm) * Each data point represents a tidal volume that produced PCO 2 = 40 torr.

Bunnell JB, Karlson KH, Shannon DC. Am Rev Resp Dis. 1978;117(Part 2):289.

Various Forms of HFV

HFPPV: High Frequency Positive-Pressure Ventilation HFJV: High Frequency Jet Ventilation HFOV: High Frequency Oscillatory Ventilation HPFM: Hocus Pocus Friggin’ Magic

Physiologic Basis for Rapid, Small Tidal-Volume Breathing Henderson was intrigued by the shallow breathing of panting dogs in 1915.

He wondered how dogs could pant indefinitely without becoming hypoxic or hypercapnic.

So, he designed an experiment to find out.

“Flow Streaming”

He then stuck his tongue over the end of the tube to stop the flow. Diffusion took over as flow stopped, and the effect disappeared.

Henderson filled his mouth with tobacco smoke and blew it into a glass tube in one quick puff.

Engineers call this phenomenon

transitional flow,

because it is moving from laminar to turbulent flow. I call it

flow streaming;

what we try to create with our Jet nozzles.

Conventional Ventilator

High-Frequency Flow-Interrupting Valve

High Frequency Jet Ventilation

Servo-Controlled HFJV Flow Jet Nozzle PEEP Valve CMV Flow PEEP & CMV PIP

HFJV V T

~

0.5 mL/kg

Patient

CV V T

~

4 – 10 mL/kg

Exhaust

Inhalations are active. Exhalations are passive. Spontaneous breathing is enabled by the CMV, which can also help with alveolar recruitment.

The Life Pulse “Jet ” Video operating instructions: www.bunl.com

LifePort ETT Adapter

Pressure Monitoring Line 15-mm Connector Jet Injection Port Jet Port Cap ET Tube Connector

LifePort ETT Adapter

15mm Adapter for CV circuit Pressure Monitoring Port Jet Gas Delivery Port ETT to Patient

So, be ready to suction!

The train of tiny V T s moves high pO 2 gas close to alveoli, while not pushing CO 2 – rich gas ahead of it, thereby reducing effective V D .

Path of least resistance for exhaled gas is around the gas streaming in, along airway walls.

Flow Streaming Tracheal Esophageal & other Fistulae.

HFJV gas streams into the airways with high velocity. It swirls down the airways, splitting at bifurcations, always seeking the path of least resistance.

Fresh gas dissects through the dead space, shooting past upper airway leaks.

Successful high frequency ventilation is achieved via good working knowledge of: 1. lung mechanics 2. pathophysiology, and 3. characteristics of specific HFV devices After 30 years of experience, our knowledge has grown exponentially . . .

Investigational Use of HFJV

Attending physician thought the baby was going to die. (1983)

Serendipity

In 1983, preterm babies who developed PIE always died.

We attributed our success with PIE to our smaller tidal volumes and lower airway pressure. WE WERE WRONG.

PIE pathophysiology, which Dr. Jackie Coalson* patiently explained to me, makes it ideally suited to HFJV.** * Univ. of Texas, San Antonio, Dept. of Pathology ** Dr. Kurt Albertine updated my understanding years later.

Pulmonary Interstitial Emphysema Restrictive Lung Disorder Tension PIE restricts alveolar expansion.

Obstructive Interstitial gas increases airway resistance upstream from injury, increasing its T C gas trapping.

It is counter-productive to ventilate lung units affected by PIE.

NON-HOMOGENEOUS LUNG DISEASE High R aw limits HFJV ventilation of injured regions.

Atelectatic areas with more patent airways get more HFJV ventilation.

PIE High R AW (Longer Time Constants) RDS Low C L (Shorter Time Constants)

•

Once HFJV was FDA approved (1988) for rescuing babies with PIE and other airleaks, Jet users set out to prove that HFJV could also prevent lung injury . . .

•

That’s what everyone wanted to do in the first place.

•

Once HFOV was FDA approved (1992) for preventing lung injury, Oscillator users set out to prove HFOV could also rescue injured babies . . .

•

Even early HFV adopters were hesitant to use such a disruptive technology on babies they thought they could save the old fashioned way (CMV).

Both camps had something to learn.

HFJV users had to learn

why

HFOV was successful with RDS (i.e., alveolar recruitment; MAP).* This knowledge not only enabled us to prevent lung injury, it greatly improved our success with PIE. * Dr. Alison Froese, Dept. of Anesthesiology, Kingston, ON

Alveolar Recruitment & PaO

2

Rate PIP PEEP I-time HFJV 420 20 4 .020

CV CPAP 0 4 Lung Volume PaO 2 < 50 time

The Role of CMV during HFJV

Ventilation HFJV PIP Rate Humidifier Manual Breath Button Oxygenation CMV PIP Rate Pressure Monitoring CV Flow ≈ 5 Lpm LifePort adapter Jet Flow ≈ 1 Lpm

V L

Recruiting with Inadequate PEEP

Rate PIP PEEP I-time HFJV 420 20 4 .020

CV 3 30 4 2.0

PEEP is too low!

Time

Recruiting Lung Volume with IMV Breaths

Rate PIP PEEP I-time HFJV 420 20 8 .020

CV 6 20 8 0.4

Higher PEEP enables recruitment!

V L Time

PaO 2 after Alveolar Recruitment

PaO 2 = 500 Lung Volume Rate PIP PEEP I-time HFJV 420 20 8 .020

CV CPAP 0 8 time

Lung Protective Ventilation

Recruitment Stabilization Protection Get alveoli open Keep them open Ventilate as gently as possible

What About HFJV vs. HFOV?

HFJV and HFOV Major Differences 1. How they control and manage I-time, PIP, exhalation, and V T 2. Jet nozzle vs. oscillating diaphragm 3. How much flow they use (efficiency) 4. Jet used in tandem with CMV to enable spontaneous breathing, alveolar recruitment, and PEEP / MAP control.

5. Patient interface (ETT connection)

HFV Device Differences

HFOV: active exhalation; fixed I:E; V T dependent on Rate, flow ≈ 10-20 Lpm.

HFJV: passive exhalation; adjustable I:E and I-time, V T jet flow ≈ independent of Rate, 1 Lpm (NICU).

Differences have physiologic consequences.

High Frequency Oscillation

Oscillating Piston or Diaphragm

PEEP Valve

HFOV Flow Patient Exhaust

Must use higher MAP. Spontaneous breathing is impeded.

Consequences of Active Exhalation • • • gas is sucked out of the airway pressure drops upstream of alveoli airways lack structural strength

+ + +

“Choke Point” Pressure outside > pressure inside airways

+ + + + + + + + + + + + +

Back-pressure (higher PEEP/MAP) splints airways open, allowing gas to enter and exit.

+ + +

HFOV works best when increased MAP works.

+ + + + + +

Oxygenation and Ventilation are Decoupled during HFV - Oxygenation depends on alveolar recruitment and stabilization (MAP).

- Ventilation is accomplished by HFV.

V

T

Controls PaCO

2

During HFV V

CO2 ≈

f

x

V

T 2 V T is most important, even though HFJV V T < 1 mL/Kg.

∆P (PIP - PEEP) creates V T .

R AW impedes V T delivery to injured areas. I-time enables delivery of V T .

Keys to treating lung injury*: Use the shortest I-time possible (reduces gas trapping and ventilation of lung areas that are already injured).

Alleviate gas trapping (use longer E-time).

Use smallest possible V T , minimal ∆P, and

optimal

mean airway pressure.

HFOV

Rate 15 Hz 10 Hz 8 Hz 6 Hz T I T E I:E 0.022 0.044 1: 2 0.033 0.067 1: 2 0.042 0.084 1: 2 0.056 0.111 1: 2 4 Hz

HFJV

660 bpm 420 bpm 0.083 0.167 1: 2 0.020 0.071 1: 4 0.020 0.122 1: 6 360 bpm 0.020 0.147 1: 7 300 bpm 240 bpm 0.020 0.180 1: 9 0.020 0.230 1: 12 Typically held constant Typically held constant

HFOV

Rate 15 Hz 10 Hz 8 Hz 6 Hz T I T E I:E 0.022 0.044 1: 2 0.033 0.067 1: 2 0.042 0.084 1: 2 0.056 0.111 1: 2

HFJV

4 Hz 660 bpm 0.083 0.167 1: 2 0.020 0.071 1: 4 420 bpm 0.020 0.122 1: 6 360 bpm 0.020 0.147 1: 7 300 bpm 240 bpm 0.020 0.180 1: 9 0.020 0.230 1: 12 Changing Rate changes T I and thereby V T . V T I V T depends on ,

not

MIN Rate.

changes with Rate.

HFOV HFJV

Rate 15 Hz 10 Hz 8 Hz 6 Hz T I T E I:E 0.022 0.044 1: 2 0.033 0.067 1: 2 0.042 0.084 1: 2 0.056 0.111 1: 2 More time to get gas in 4 Hz 600 bpm 0.083 0.167 1: 2 0.020 0.080 1: 4 420 bpm 0.020 0.122 1: 6 360 bpm 0.020 0.147 1: 7 300 bpm 240 bpm 0.020 0.180 1: 9 0.020 0.230 1: 12 More time to get gas out

Why do we need all this flexibility?

BPD / Pulmonary Hyperinflation

Where is the gas trapped?

Consider a model alveolus surrounded by interstitial gas.

Will lowering PEEP / MAP help?

Or will it just make matters worse?

Lowering PEEP may compromise functioning alveoli with no improvement of hyperinflation.

Try using no CMV, moderate PEEP, and low HFJV rate (240 bpm, I:E = 1:12) to give trapped gas more time to get out.

What patients present the biggest challenge to HFVs and CMVs?

• Typical settings for both HFJV and HFOV will not work for the most severe PIE, MAS, and BPD babies. • CMVs got many such patients into their predicaments.

• Patients with injured lungs require longer E-times to enable complete expiration (treat hyperinflation).

• HFVs at low rates sometimes work, but there are other issues that must be addressed (MAP, I-time & E-time).

T I I T E HFJV 360 300 240 * More time to get gas in Good for various degrees of RDS + PIE *** *** *** ** More time to get gas out Good for various degrees of MAS & BPD, PICU kids *** Still enough time to get gas out as well

Hypoplastic Left Heart Syndrome (complicated by CLD & sepsis) On HFOV 2 wks; here on MAP 16, 5 HZ,  P 45, 55% FiO2.

Switched to Jet On HFJV 4 hrs; here on MAP 14, 7 HZ,  P 22, 45% FiO2.

HFJV can ventilate patients when all else fails. Term baby with ABCA3, a fatal surfactant deficiency.

Kelligar Neal at 9 yrs, playing Elton John’s piano in Vegas.

Three months on HFJV before she got new lungs in St. Louis, MO.

www.kelligar.com

Please become an organ donor.

Some hospitals: HFJV > 200 babies/yr • Micro-preemies as soon as they fail nCPAP • All PIE / RDS, other air leaks, CDH, MAS, PPHN, pneumonias, cardiac surgery niños • PICU: bronchiolitis, acute lung injuries, ARDS w/ or w/o pulmonary hypertension, bronchospasm, and/or ↑ ICP (i.e., niños who need better control of PaCO 2 • Overall, 1 new baby/hr HFJV

After 40 years of research and 30 years treating > 100,000 infants and children, we have refined and condensed our HFJV guidelines to a few key concepts.

1. Establish criteria for initiating HFJV and stick to them.

2. Apply principles of lung protective ventilation (recruit, stabilize, and ventilate gently).

3. Consider lung mechanics and pathophysiology.

Common HFV Mistakes

1. Not recruiting and maintaining proper lung volume 2. Inadequate understanding of HFV device operation & limitations 3. Applying HFV too late 4. Discontinuing HFV too soon

24/7 Hotline: 800-800 HFJV

www.bunl.com

Put it on your cell phone!

Typical advice from our Hotline: - Optimize MAP via PEEP, especially when FiO 2 > 50% - Adjust PIP as needed following PEEP titration - If lungs are hyperinflated: lower rate to 360, 300, 240 as needed to eliminate inadvertent PEEP - Minimize CMV support except for alveolar recruitment - For hypercapnea when PIP > 35 cm H 2 O: increase I-time as needed in steps (0.026, 0.030, 0.034)

Servo Pressure

Servo Pressure is the Jet’s internal driving pressure that controls V MIN .

It is feedback controlled by Jet’s microprocessor to adjust

gas flow

so monitored PIP = set PIP.

JET VALVE

ON OFF

SERVO PRESS MAP 3.0

12.9

ALARMS RESET READY SILENCE UPPER LIMIT LOWER LIMIT UPPER LIMIT LOWER LIMIT Upper and lower alarm limits are automatically set around SERVO PRESS and MAP. These limits can be manually adjusted for sensitivity after they are automatically set.

Therefore, you choose to what degree you want to be alerted to changes in patient’s lung mechanics.

Monitor Servo Pressure

• If S.P. (GOOD) you may need to wean PIP to keep PaCO 2 and pH in target range. • If S.P. (BAD) you may consider suctioning, re-position ETT, or treat bronchospasms or pneumothoraces… • If in doubt, call us: 1-800-800-HFJV, available 24/7; everyone can benefit from coaching once in a while...

As ventilation improves:

1. Reduce HFJV PIP.

2. Reducing HFJV Rate also works, and it encourages spontaneous breathing.

HFJV Rate 600 bpm 540 480 420 360 300 240 I : E 1 : 4 1 : 5 1 : 5.3

1 : 6 1 : 7.3

1 : 9 1 : 11.5

More time for spontaneous breathing!

As oxygenation improves:

1. Wean big breaths first.

(Get CMV into CPAP mode.) 2. Wean FiO 2 before PEEP/MAP.

Last Step to Success Wean to nasal CPAP

It’s time to extubate when…

20 Patient is breathing spontaneously.

HFV P is not causing much chest wiggle. FiO 2 < 0.3 and MAP ~ 8 or less Set Nasal CPAP = HFJV MAP

P

cm H 2 O 15 10 5 0.0

0.5

2.0

1.0

Time, seconds 1.5

In Conclusion…

HFV is inherently safer than CMV with one exception: it is easy to hyperventilate patients.

• • Carefully monitor PaCO 2 movement seems excessive.

When should HFV be used?

My Bias: 1. HFOV should be used early; it is not an ideal rescue ventilator.

2. HFJV is a great rescue ventilator, but it should also be used early.

HFJV is easy to use if: • Plan ahead (Who will you “Jet?”) • Lung-Protective Ventilation • Follow HFJV Guidelines • Call 24/7 Hot-Line for support

HFJV advantages: 1) Uses smallest tidal volumes 2) Uses least airway/alveolar pressure; excellent way to deliver NO 3) Helps clear excessive airway secretions 4) Helps ventilation/perfusion matching in non homogeneous lung disease 5) CMV helps you find and maintain optimal PEEP 6) Helps get infants extubated more quickly

Familiarize yourself with

www.bunl.com

HFJV Protects Lungs!

www.bunl.com

[email protected]

- 800-800-HFJV (4358) (Available 24/7) “My future’s so bright, I gotta wear shades.”

4-Step Startup

How to transition to HFJV from CMV or HFOV quickly, easily, and successfully.

Step 1: Startup Decisions

• Establish startup protocol • Most importantly: Who to HFJV CDH, pneumonia, preterm RDS PIE, PTX, other air leaks MAS / PPHN, BPD, ARDS cardiac surgery babies

Startup HFJV Settings

• Rate: 420 bpm if patient is preterm, or slower he is larger or suffering from a lung condition that may cause gas trapping (e.g., MAS, PIE, BPD).

• PIP: equal to or a few cm H 2 O less than current CMV or HFOV PIP.

• I-time: 0.020 sec.

CMV Settings

• Adjust CMV for gentle alveolar recruitment using 5 bpm.

•

This setting is temporary.

• Goal: CMV rate ~ 0 bpm (CPAP) once we find optimal PEEP in Step 3.

Startup CMV PEEP

• Raise PEEP by 2 cm H 2 O when transitioning from CMV in order to preserve MAP and lung volume. • Adjust PEEP as necessary to maintain same or slightly lower MAP when transitioning from HFOV.

CMV HFJV

CMV HFJV You must raise PEEP to maintain MAP PEEP (Fight PEEPaphobia!) Time This a general recommendation, even for air leaks, but if PaCO 2 in the Step 2.

Step 2: Fine-Tune Ventilation (PaCO

2

)

• Raise or lower HFJV PIP as necessary to decrease or increase PaCO 2 .

• HFJV PIP is less hazardous than CMV PIP because of smaller V T size and duration.

Step 3: Use IMV to help find & set Optimal PEEP

• Optimal lung volume requires optimal PEEP / MAP.

• Goal: FIO2 < 0.30.

Note: This step is not appropriate for cardiac patients with relatively normal lungs where PEEP may need to be minimized, and CMV at 5 bpm may be required to help keep the lungs open.

Trap

• • If oxygenation improves when you turn up IMV, there is a natural inclination to keep using IMV. --

Don’t do it! lung injury!

If you appreciate pressure-volume loops, you will appreciate that PEEP was too low.

• Raise PEEP; stop IMV. It is safer to use optimal PEEP / MAP with no IMV.

Step 4: Document Baseline Values

• Blood gases • Pulse oximetry, trancutaneous CO 2 • Servo Pressure

HFJV can hyperventilate patients with low mean airway pressure. - Infants with congenital heart disorders with passive pulmonary blood flow (Glenn and Fontan procedure patients). See Dr. Meliones’ lecture on www.bunl.com

.

- PICU patients with head trauma and crushed chest injuries.

Why isn’t everyone using HFJV?

HFJV is a disruptive technology (i.e., it changes how people do things), and many people resist change.

No one

sets

expiratory time.

Set Rate and T I to create T E and accommodate

expiratory

time-constants: T E = 1 / Rate - T I I:E = 1: T E / T I

Rate T I T E I:E HFJV 600 420 360 300 240 * More time to get gas in 0.020 0.080 1: 4 0.020 0.122 1: 6.1

Good for RDS Good for various degrees of RDS + PIE *** *** *** ** More time to get gas out Good for various degrees of MAS & BPD, PICU kids *** Still enough time to get gas out as well

HFJV Rate T I T E I:E 420 0.020 0.122 1: 6 420 0.024 420 0.028 420 0.034

20% 40% 70%

0.118

3%

0.114

7%

0.108

11%

1: 5 1: 4 1: 3

Not so scary

Scary!

Lung Protective Ventilation

Recruitment Stabilization Protection Get alveoli open Keep them open CMV with appropriate PEEP Ventilate as gently as possible HFJV HFV Minimize V T , PIP, and MAP

Common HFV Mistakes

1. Inadequate understanding of HFV devices and how to match settings to specific pathophysiologies 2. Applying HFV too late, or not at all 3. Discontinuing HFV too soon

CASE HISTORY

7-year old, previously healthy, 25-kg girl experienced severe crushed-chest injury in a movie theater lobby. It was opening night for “Titanic,” and large concrete dividers connected by chains were being used to control the crowd. A divider tipped over and fell on her.

DIAGNOSIS

• • • • Bilateral Pneumothoraces Subcutaneous Emphysema Lacerated Liver Tracheal Tear

Intraoperative Findings

• • Large tear of membranous trachea involving right and left mainstem bronchi Prolonged and difficult surgery

Initial Mechanical Ventilation

• Ventilation extremely difficult both intra- and post-operatively.

• Extremely poor compliance.

• HFOV (SensorMedics 3100A): PCO 2 ↑ 285 and pH ↓ 6.65

Other modes attempted with Siemens Servo 300 C (Siemens-Elema, Sweden) PRVC: V T < 10 cc/kg, PEEP +5, Rate 25-35. Result = PIP > 60.

Pressure Control: PIP 35 - 40, Rates up to 140. Result = V T < 25 cc (< 1 mL/kg) and PaCO 2 > 200.

IN EXTREMIS!!

• • pH from 6.80 - 6.65

PCO 2 from 195 to 285 mm Hg • • Frequent desaturations Hemodynamic instability: fluid resuscitation and dopamine 20 mg/kg/min.

• ECMO: too unstable to transport!

•

HFJV Trial ?

HFV Rate: 240 • CV Rate: 30 • CV PIP HFV PIP: 60 + • PEEP / CPAP: 10 14 42

HFJV Results

1hr - 15 min: PaCO 2 285 72 pH 6.65 7.21

2hr - 10 min: PaCO 2 26 mmHg pH 7.52

RECOVERY

Day 6:

Changed to conventional ventilation

Day 8:

Repeat bronchoscopy revealed good healing of tear w/o granuloma or tracheitis

Day 10:

Chest tubes out

Day 11:

Extubated

Day 16:

Discharged home

HFJV Rate 600 bpm 540 480 420 360 300 240 I : E 1 : 4 1 : 5 1 : 5.3

1 : 6 1 : 7.3

1 : 9 1 : 11.5

∆P (PIP - PEEP) creates V T so it should not change with Rate. V CO2 ≈ f x V T 2 Some patients need more time for exhalation.

HFJV and HFOV Waveform Attenuations

20 15 PIP falls dramatically MAP falls slightly PEEP stays constant CMV 10 5 0 0 10 Airway Generations MAP MAP PEEP PIP falls dramatically MAP stays constant PEEP rises 20

How HFJV Rate PaCO

2 • May increase Rate to reduce PaCO 2 if patient is preterm with no evidence of gas trapping. • Must decrease Rate if gas trapping is indicated by inadvertent PEEP or hyperinflation on chest xray.

CMV Flow

X X

Patient PEEP Valve PEEP & CMV PIP Exhaust

Rate T I T E I:E HFJV 600 420 360 300 240 * More time to get gas in 0.020 0.080 1: 4 0.020 0.122 1: 6.1

Good for RDS Good for various degrees of RDS + PIE *** *** *** ** More time to get gas out Good for various degrees of MAS & BPD, PICU kids *** Still enough time to get gas out as well

LifePort Adapter

Jet Port Inspired gas is injected down the ETT in high velocity spurts.

Pressure Monitoring Port PIP is measured here and filtered to estimate PIP at the tip of ETT.

1. Barotrauma - too much pressure (PIP/MAP) 2. Volutrauma - tidal volumes are too big 3. Atelectrauma - alveoli are allowed to collapse

Atelectrauma Inadequate recruitment and maintenance of lung volume

The only type of lung injury not inherently addressed by HFV PEEP / MAP set too low

P-V curves produced from ex-vivo, non perfused rat lungs before & after 2 hrs of ventilation with 4 distinct strategies: No PEEP Inadequate PEEP Appropriate PEEP Control (no CMV) = before ventilation Δ = after 2 hours

Slutsky, A. S. Chest 1999;116:9-15S-a

It is most important to

optimize

PEEP rather than try to minimize it. (Atelectrauma!)

My Background

I will discuss unlabeled uses of HFV.

• • • I am a biomedical engineer, trained to: solve problems approach solutions from basic engineering & physiologic principles recognize value and limitations of clinical trials

Mea Culpa

• • • I am an old plodder: been trying to figure out mechanical ventilation of babies since 1971 conceived HFV in 1975 still learning how to master it I am slow, but I haven’t given up.

My Job: Get you comfortable with HFJV.

1. Discuss how and why HFJV and HFOV work and don’t work 2. Explain when and why HFJV might work better than HFOV 3. Introduce HFJV startup protocol 4. Discuss how to optimize HFJV 5.

Answer questions…

Your Job: Ponder, Plan Ahead

1. Should you implement HFJV?

2. Who will you treat with HFJV?

3. When will you start?

4. What strategies will you use?

So, how does HFV fit into this picture?

How can I be so audacious?

1.

2.

I’m old. I’m tired of dancing around the obvious (to me).

I’m confident. I have been doing this for 40 years. 3. HFJV has been used to help save > 100,000 patients. 4. One new patient goes on HFJV somewhere once every hour.

Learning and training never ends: animal studies in Australia (Jane Pillow) hospital training programs (work both ways) 24/7 Hotline supports users / collects data

Managing Difficult Patients

PaCO 2 too high?

F I O 2 too high?

What is your strategy?

What is Servo Pressure?

What does chest xray show?

Where do you have PEEP set?

HFJV is easy to use if: • Plan ahead (Who will you “Jet?”) • Lung-Protective Ventilation • 4-Step Startup Protocol • Follow HFJV Guidelines • Call 24/7 Hot-Line for support