High Frequency Oscillatory High Frequency Oscillatory Ventilation of the Ventilation of the

Large Pediatric and Adult Large Pediatric and Adult PatientPatient

Jason Higgins, BS, RRTJason Higgins, BS, RRT

HFOV Clinical Sales SpecialistHFOV Clinical Sales Specialist

Cardinal Health/VIASYSCardinal Health/VIASYS

ObjectivesObjectives

• Brief history of HFOVBrief history of HFOV• Who will benefit from HFOVWho will benefit from HFOV• When should you initiate HFOVWhen should you initiate HFOV• How do you initiate HFOVHow do you initiate HFOV

• Oxygen strategiesOxygen strategies• Ventilation strategiesVentilation strategies

• When do you discontinue HFOVWhen do you discontinue HFOV

A Brief History of HFVA Brief History of HFV

1990 2001

HFOV Approved For Use In Neonates

1982

1991

1987

P-V Curve using Lung CT in ARDS

1985

Animal Studies -Role of P-V in

Lung Injury

HFOV in Animals

1993

FDA Approval of 1010 HFV

Ventilator Strategies and Inflammatory

Mediators

1997

APRV

HFOV Adults

1977

Klain & Smith HFJV

1995

HFOV Approved For

Use in Peds

3100A Ventilator3100A Ventilator

•Approved in 1991 for Neonatal Application for the treatment of all forms of respiratory failure

•Approved in 1995 for Pediatric Application, with no upper “weight limit”

•For treating selected patients failing conventional ventilation

High Frequency Oscillatory High Frequency Oscillatory VentilationVentilation

High Frequency Oscillatory High Frequency Oscillatory VentilationVentilation

3100B Ventilator3100B Ventilator

•Approved for sale outside the US in 1998 for patients weighing > 35 kg failing CMV

•Approved September 24, 2001 by the FDA for sale in the US

High Frequency Oscillatory High Frequency Oscillatory VentilationVentilation

IS THERE A DIFFERENCE BETWEEN THE 3100A AND

THE 3100B?

3100 A3100 A 3100 B3100 B

Piston centering adjustable

Piston centering

connected to I:E Ratio

Limit Adjust Button

No Limit Adjust Button

WhoWho Will benefit fromWill benefit from

HFOV 3100B?HFOV 3100B?

Normal Chest RadiographNot-So-Normal Chest Radiograph

HFOV 3100BHFOV 3100B

• Only Pathology studied to date has been Only Pathology studied to date has been ARDSARDS

• Questions about management of adults Questions about management of adults with massive airleak?with massive airleak?

• Questions about management of Questions about management of Respiratory Failure based on any other Respiratory Failure based on any other disease processdisease process

The American – European The American – European Consensus Criteria for ARDSConsensus Criteria for ARDS

< 18 mmHg or no

Clinical evidence

Of left atrial

hypertension

Bilateral

Infiltrates on

Frontal chest

Radiograph

PaO2/FiO2

< 200 torr

(regardless of

PEEP level)

Acute onset

Pulmonary Artery

Occlusion Pressure

Chest RadiographOxygenationTiming

ARDS Pulmonary Injury ARDS Pulmonary Injury SequenceSequence

• Phase 1 Early Exudative ProcessPhase 1 Early Exudative Process

• Phase 2 Proliferative (Day 5-10)Phase 2 Proliferative (Day 5-10)

• Phase 3 Fibrotic (Day 10-14)Phase 3 Fibrotic (Day 10-14)

Acute Respiratory Distress Acute Respiratory Distress SyndromeSyndrome

• 150,000 cases / year150,000 cases / year• 75,000 deaths / year75,000 deaths / year• $5,000,000,000 / year$5,000,000,000 / year• No curative treatment on the horizonNo curative treatment on the horizon

Ware and Matthay NEJM 342 (18): 1334

Etiology of ALI / ARDSEtiology of ALI / ARDS

Direct CausesDirect Causes• AspirationAspiration• PneumoniaPneumonia• EmboliEmboli• Near DrowningNear Drowning• Reperfusion Reperfusion

InjuryInjury• Inhalation InjuryInhalation Injury

Indirect Causes

• Sepsis

• Shock/Trauma

• Pancreatitis

• Overdose

• Transfusion

• Drug OD

• CP Bypass

Ventilator Induced Lung InjuryVentilator Induced Lung Injury

• All forms of positive pressure ventilation All forms of positive pressure ventilation (PPV) can result in ventilator induced lung (PPV) can result in ventilator induced lung injury (VILI)injury (VILI)

• VILI is the result of a combination of the VILI is the result of a combination of the following processesfollowing processes

•BarotraumaBarotrauma•VolutraumaVolutrauma•AtelectraumaAtelectrauma•BiotraumaBiotrauma

Slutsky, Chest, 1999

BarotraumaBarotrauma• High airway pressures during PPV can cause lung High airway pressures during PPV can cause lung

overdistension with gross tissue injuryoverdistension with gross tissue injury• This injury can allow the transfer of air into the This injury can allow the transfer of air into the

interstitial tissues at the proximal airwaysinterstitial tissues at the proximal airways• Clinically, barotrauma presents as pneumothorax, Clinically, barotrauma presents as pneumothorax,

pneumomediastinum, pneumopericardium, and pneumomediastinum, pneumopericardium, and subcutaneous emphysemasubcutaneous emphysema

Slutsky, Chest, 1999

VolutraumaVolutrauma• Lung overdistension can cause diffuse alveolar Lung overdistension can cause diffuse alveolar

damage at the pulmonary capillary membranedamage at the pulmonary capillary membrane• This may result in increased epithelial and This may result in increased epithelial and

microvascular permeability, thus, allowing fluid microvascular permeability, thus, allowing fluid filtration into the alveoli (pulmonary edema)filtration into the alveoli (pulmonary edema)

• Excessive end-inspiratory alveolar volumes are the Excessive end-inspiratory alveolar volumes are the major determinant of volutraumamajor determinant of volutrauma

AtelectraumaAtelectrauma• Mechanical ventilation at low end-expiratory volumes Mechanical ventilation at low end-expiratory volumes

may be inefficient to maintain the alveoli openmay be inefficient to maintain the alveoli open

• Repetitive alveolar collapse and reopening of the Repetitive alveolar collapse and reopening of the under-recruited alveoli result in atelectraumaunder-recruited alveoli result in atelectrauma

• The quantitative and qualitative loss of surfactant may The quantitative and qualitative loss of surfactant may predispose to atelectraumapredispose to atelectrauma

BiotraumaBiotrauma

• In addition to the mechanical forms of injury, PPV In addition to the mechanical forms of injury, PPV activates an inflammatory reaction that perpetuates activates an inflammatory reaction that perpetuates lung damagelung damage

• Even ARDS from non-primary etiologies will Even ARDS from non-primary etiologies will result in activation of the inflammatory cascade result in activation of the inflammatory cascade that can potentially worsen lung function that can potentially worsen lung function

• This biological form of trauma is known as This biological form of trauma is known as biotraumabiotrauma

Lung Inflation Patterns on

multi-Scan CT

30 kg Pig

Post Saline Lavage

PCV

mPaw 13 cmH20

PEEP 5 cmH20

Lung Inflation Patterns on

multi-Scan CT

30 kg Pig

Post Saline Lavage

PCV

mPaw 23 cmH20

PEEP 15 cmH20

Pressure and Volume Swings

INJURY

INJURY

During CMV, there are swings between the zones of injury from inspiration to

expiration

Pressure and Volume Swings

INJURY

INJURY

CMVCMV

During CMV, there are swings between the zones of injury from inspiration to

expiration

WhyWhy Should you treat ARDS Should you treat ARDS

with HFOV?with HFOV?

Pressure and Volume Swings

INJURY

INJURY

During HFOV, the entire cycle operates in the “safe window” and avoids the injury

zones

Pressure and Volume Swings

INJURY

INJURY

HFOVHFOV

During HFOV, the entire cycle operates in the “safe window” and avoids the injury

zones

Breaking the Cycle!!Breaking the Cycle!!Lung Recruitment & ProtectionLung Recruitment & Protection

• GoalGoal• Nearly constant alveolar volumeNearly constant alveolar volume• Nearly constant alveolar pressureNearly constant alveolar pressure• Lower peak airway pressureLower peak airway pressure

• MethodMethod• High Frequency Oscillatory High Frequency Oscillatory

VentilationVentilation

• Optimal Lung Volume Optimal Lung Volume

““Open up the lung… Open up the lung… and keep it open!”and keep it open!”

1992BurkhardLachmann

HFOV and Lung Recruitment

mPaw 15 cmH2O

Pre-recruitment

mPaw 15 cmH2O

Post-recruitment

Alexandre Rotta, M.D. 2004

Recruitment of lavaged animal

lung using increasing

levels of mPaw

Lung Recruitment using HFOV

Ventilator Induced Lung Ventilator Induced Lung Injury Injury (VILI)(VILI)

• BaroBarotraumatrauma• extralveolar air caused by structural extralveolar air caused by structural

disruption due to high airway pressure disruption due to high airway pressure which is often the result of large lung which is often the result of large lung volumes and not high airway pressure per volumes and not high airway pressure per se. se. "Barotrauma is Volutrauma" Dreyfuss D, et al."Barotrauma is Volutrauma" Dreyfuss D, et al.

• VoluVolutraumatrauma• regional lung overdistension caused by regional lung overdistension caused by

overinflation and uneven expansion of the overinflation and uneven expansion of the lungslungs

• AtelecAtelectraumatrauma• shear forces generated during cyclic shear forces generated during cyclic

closure and reopening of terminal airways.closure and reopening of terminal airways.

• BioBiotraumatrauma• activation of effector cells to release activation of effector cells to release

inflammatory mediators due to physical inflammatory mediators due to physical stresses associated with mechanical stresses associated with mechanical ventilation.ventilation.

Ventilator Induced Lung Ventilator Induced Lung Injury Injury (VILI)(VILI)

WhenWhen Do you initiateDo you initiate

HFOV?HFOV?

Thinking of starting HFOV??? Don’t wait too late!!!

Current Trends in Conventional Current Trends in Conventional Ventilation StrategiesVentilation Strategies

• ARDSnet Study (6 ml/kg)ARDSnet Study (6 ml/kg)• High PEEP lower Vt strategiesHigh PEEP lower Vt strategies

• PC-Inverse RatioPC-Inverse Ratio• APRV/Bi-Level APRV/Bi-Level • HFOVHFOV• Therapeutic ModalitiesTherapeutic Modalities

• Lung Recruitment ManeuversLung Recruitment Maneuvers• Kinetic TherapyKinetic Therapy

• If FIO2 > .60 - .70 and PEEP > 10 – 14 cmH2O while not being able to maintain SpO2 > 88%

• Unable to maintain Pplat < 30 cmH2O

• mPaw on CV is > 24 cmH2O

• Patient requiring paralysis for oxygenation

• Earlier intervention better

When Should HFOV be When Should HFOV be Initiated?Initiated?

Open Lung Ventilation

0 10 20 30 40

0

0.4

0

.8

1.2

1

.6

normal

ARDS

airway pressure (cm H2O)

volu

me

abo

ve F

RC

(lit

ers)

lower inflectionpoint

upper inflectionpoint

Alveolar Volumetric ChangesAlveolar Volumetric Changes

Insp.

Exp.

Conventional HFOV

Insp. Exp.~ ~

HowHow Do you initiateDo you initiate

HFOV?HFOV?

Let’s try HFOV!!!Let’s try HFOV!!!

mPaw

PHz

Theory of OperationTheory of Operation

• Controls for Oxygenation and Ventilation are Controls for Oxygenation and Ventilation are mutually exclusivemutually exclusive

• Oxygenation is primarily controlled by the Oxygenation is primarily controlled by the Mean Airway Pressure (mPaw) and the FiOMean Airway Pressure (mPaw) and the FiO22

• Ventilation is primarily determined by the Ventilation is primarily determined by the stroke volume (Delta-P) and the frequency of stroke volume (Delta-P) and the frequency of the ventilator.the ventilator.

HFOV = Super CPAPHFOV = Super CPAP

FiO2 is set with FiO2 is set with

blenderblender

Mean Airway Pressure Mean Airway Pressure (mPaw)(mPaw)

Power KnobPower Knob

Amplitude (Amplitude (∆∆P)P)

Frequency Frequency (Hz)(Hz)

Bias FlowBias Flow

Oxygen StrategiesOxygen Strategies

Mean Airway Pressure (mPaw)Mean Airway Pressure (mPaw)

FiO2 is set with blenderFiO2 is set with blender

Oxygenation – Clinical TipsOxygenation – Clinical Tips

• Initiate HFOVInitiate HFOV• FiO2 of 1.0FiO2 of 1.0• mPaw of 5 cmHmPaw of 5 cmH22O greater than mPaw on CMVO greater than mPaw on CMV

• Increase mPaw by 1-4 cmHIncrease mPaw by 1-4 cmH22O to achieve O to achieve optimal lung volumeoptimal lung volume

• Optimal lung volume is determined by Optimal lung volume is determined by increasing SpOincreasing SpO22 while maintain FiO while maintain FiO22 or or weaning FiOweaning FiO22

• Diaphragm Diaphragm T8-T9 on CXR T8-T9 on CXR• Maintain mPaw while weaning FiOMaintain mPaw while weaning FiO22 to < .60 to < .60

Oxygenation – Clinical TipsOxygenation – Clinical Tips

• Follow CXR to assess lung expansionFollow CXR to assess lung expansion• If diaphragm is round and between T8-T9, If diaphragm is round and between T8-T9,

continue to wean FiOcontinue to wean FiO22

• If diaphragm is flattened and greater than T-9, If diaphragm is flattened and greater than T-9, wean mPaw by 1 cmHwean mPaw by 1 cmH22O and reassess CXRO and reassess CXR

• Should be able to wean FiOShould be able to wean FiO22 to < .60 in first 12 to < .60 in first 12 hours hours • If unable to reach FiOIf unable to reach FiO22 .60, consider .60, consider

recruitment maneuver by increasing mPaw recruitment maneuver by increasing mPaw (sustained inflation)(sustained inflation)

Oxygenation – Clinical TipsOxygenation – Clinical Tips

• Ensure adequate intravascular volume and cardiac outputEnsure adequate intravascular volume and cardiac output• Consider volume loading or initiate inotropesConsider volume loading or initiate inotropes

• Improves V/Q matchingImproves V/Q matching• High intrathoracic pressures can impede venous return High intrathoracic pressures can impede venous return

and adversely affect cardiac outputand adversely affect cardiac output• Closely monitor hemodynamic statusClosely monitor hemodynamic status• Utilize pulse oximeters and transcutaneous COUtilize pulse oximeters and transcutaneous CO22 monitors monitors

to set appropriate HFOV settings in between ABGsto set appropriate HFOV settings in between ABGs

Oxygenation StrategiesOxygenation Strategies

mPaw until SpO2 stabilizes 88 - 94% and mPaw until SpO2 stabilizes 88 - 94% and begin to begin to FiO2 to 60%FiO2 to 60%

• Avoid hyperinflation on CXR Avoid hyperinflation on CXR

• Optimize preload, myocardial functionOptimize preload, myocardial function

CLINICAL TIPS-– Must have adequate mPaw and

hemodynamic performance– Perfusion must be matched to ventilation

for adequate oxygenation– Chest x-rays and oximetry are necessary

OxygenationOxygenation

OxygenationOxygenation

PVR is increased with:– Atelectasis

– Loss of support for extra-

alveolar vessels –Over expansion

– Compression of alveolar capillary bed

The lung must be recruited, but guard against over expanding

Ventilation StrategiesVentilation Strategies

Ventilation StrategiesVentilation Strategies

• Alveolar ventilation during CMV is defined as:

F x Vt

• Alveolar Ventilation during HFV is defined as:

F x Vt 2 (squared)

• Therefore, changes in stroke volume delivery (as a function of Delta-P, Freq., or % Insp. Time) have the most significant affect on CO2 elimination

Amplitude (Amplitude (∆∆P) Power KnobP) Power Knob

SensorMedics 3100BSensorMedics 3100B

• Electrically powered, electronically controlled piston-diaphragm oscillator

• mPaw of 5 - 55 cmH2O

• Pressure Amplitude from 8 - 130 cmH2O

• Frequency of 3 - 15 Hz• % Inspiratory Time 30% - 50%

• Flow rates from 0 - 60 LPM

Primary Control for PaCOPrimary Control for PaCO22

• Amplitude (Amplitude (∆∆P)P)

• The power knob regulates the force with which the The power knob regulates the force with which the piston moves from baselinepiston moves from baseline

• The degree of deflection of the piston (amplitude) The degree of deflection of the piston (amplitude) determines the tidal volumedetermines the tidal volume

• This deflection is clinically demonstrated as the This deflection is clinically demonstrated as the “wiggle” seen in the patient“wiggle” seen in the patient

• The wiggle factor can be utilized in assessing the The wiggle factor can be utilized in assessing the patientpatient

Alveolar ventilation during CMV is defined as:

F x Vt Alveolar Ventilation during HFV is defined as:

F x Vt 2

Therefore, changes in stroke volume delivery (as a function of Delta-P, Freq., or % Insp. Time) have the most significant affect on CO2 elimination

Ventilation Strategies

• CWF- adjust Power Setting to target PaCO2 CWF- adjust Power Setting to target PaCO2 between 45-55 or normalize pHbetween 45-55 or normalize pH

• Increase the amplitude in 5 cmH2O increments Increase the amplitude in 5 cmH2O increments until the max Delta-P is reached, then decrease the until the max Delta-P is reached, then decrease the frequencyfrequency

• Some find that as they increase the amplitude 15-20 Some find that as they increase the amplitude 15-20 cmH2O with no positive effect, consider ET tube cmH2O with no positive effect, consider ET tube deflation and/or decreasing the frequency by 1 Hz deflation and/or decreasing the frequency by 1 Hz provides the desired effect.provides the desired effect.

• Allow permissive hypercarbia if indicated, Allow permissive hypercarbia if indicated, keeping pH>7.20keeping pH>7.20

VentilationVentilationThe amplitude is the primary control of ventilation. It is created by the distance that the piston moves, resulting in a volume displacement and a visual CHEST Wiggle.

It may also be described as the peak-to-trough swing across the mean airway pressure.

The power controls the force with which the piston moves

Amplitude AttenuationAmplitude Attenuation

Amplitude AttenuationAmplitude Attenuation

Frequency (Hertz)Frequency (Hertz)

Secondary control of PaCO2 is the set Frequency

Hertz (Hz): A unit of frequency equal to one cycle per secondHertz (Hz): A unit of frequency equal to one cycle per secondTherefore, 1 Hz equals 60 breaths/minuteTherefore, 1 Hz equals 60 breaths/minute

Initial Frequency SettingsInitial Frequency Settings

• Guidelines for setting the initial frequencyGuidelines for setting the initial frequency

• Adjustments in frequency are made in steps Adjustments in frequency are made in steps of of 1 Hz1 Hz

10 to 15 HzNeonates

7 to 9 HzPediatrics

5 to 6 HzAdults

FrequencyPatient Weight

FrequencyFrequency

• To evaluate the effects of changes in To evaluate the effects of changes in frequency with regards to COfrequency with regards to CO22

elimination, let us look at 2 different elimination, let us look at 2 different frequenciesfrequencies• 4 Hz4 Hz• 8 Hz8 Hz

Time X

4 Hz

8 Hz

FrequencyFrequency

Lets consider a time interval of X

Time X

4 Hz

8 Hz

The lower the frequency setting, the larger the volume displacement.

FrequencyFrequency

Time X

4 Hz

8 Hz

The higher the frequency setting, the smaller the volume displacement.

FrequencyFrequency

Time X

Therefore, lower frequencies have a larger volume displacement and improved CO2

elimination.

FrequencyFrequency

Secondary control of PaCO2 is the frequency

The frequency controls the time allowed (distance) for the piston to move

Therefore, the lower the frequency setting, the greater the volume displacement, and the higher the frequency setting, the smaller the volume displacement

VentilationVentilation

Ventilation StrategyVentilation Strategy

• If COIf CO22 retention persists, retention persists, decreasing cuff pressure to allow decreasing cuff pressure to allow gas to escape around the ET tubegas to escape around the ET tube

• This will move the fresh gas This will move the fresh gas supply from the wye connector to supply from the wye connector to the tip of the ET tubethe tip of the ET tube

• Adjust mPaw or flow to increase Adjust mPaw or flow to increase mPaw by 5 – 7 cmH2O, Deflate mPaw by 5 – 7 cmH2O, Deflate cuff to drop mPaw to ordered cuff to drop mPaw to ordered mPawmPaw

• Adequate sedation, analgesia and paralysis• Set mPaw 5 cmH2O above mPaw on CMV

• Consider Alveolar Recruitment Maneuver• Begin at “POWER” of 4 and adjust P to

achieve CWF to Mid Thigh• Set Hz at 5 - 6 (Adults), 7-9 (Pediatrics)

• unless compartment syndromes, obesity, etc• Set % IT at 33% and BF 30 Liters/minute or

greater• Consider ETT cuff leak

How Should HFOV be How Should HFOV be Initiated?Initiated?

WhenWhen Do you discontinueDo you discontinue

HFOV?HFOV?

• Wean FiOWean FiO22 for SpO for SpO22 of 88 - 92% of 88 - 92%• Target FiOTarget FiO22 .40-.60, may decrease mPaw in .40-.60, may decrease mPaw in

increments of 1- 3 cmHincrements of 1- 3 cmH22O, once FiOO, once FiO22 < .60 < .60• Monitor lung volume with CXRMonitor lung volume with CXR

• Amplitude (Amplitude ( P) is weaned by increments of 5 P) is weaned by increments of 5 cmHcmH22O for desired PaCOO for desired PaCO22

• Once optimal frequency is found, leave the Once optimal frequency is found, leave the frequencyfrequency

• However you may increase the frequency to raise However you may increase the frequency to raise the PaCO2the PaCO2

““Patience, Patience, Patience!!”Patience, Patience, Patience!!”

HFOV - Weaning StrategyHFOV - Weaning Strategy

• Conversion from HFOV to CMV• When FiO2 is < .40, mPaw is weaned to 20-24

cmH2O, patient can generally cross back over to CMV

• Improved CXR• Target mPaw on CMV equal to HFOV mPaw

• PC, Vt 6 ml/kg, PEEP >10 cmH2O, rate 15-20, I:E ratio of 1:2 or 1:1

HFOV - Weaning StrategyHFOV - Weaning Strategycontinued...continued...

PRVC, f 24, Vt 5 ml/kg, PRVC, f 24, Vt 5 ml/kg, PEEP 20 cmHPEEP 20 cmH22O, FiOO, FiO22 1.0, 1.0,

I-time 1 sec, mPaw 30 cmHI-time 1 sec, mPaw 30 cmH22O O

ABG’s 7.31/44/55/22 (OI 42)ABG’s 7.31/44/55/22 (OI 42)

HFOV, mPaw 35 cmH2O, HFOV, mPaw 35 cmH2O, ∆∆P 50 P 50 cmH2O, Frequency 4 Hz, FiO2 1.0, cmH2O, Frequency 4 Hz, FiO2 1.0,

I-time 33%I-time 33%

ABG 7.31/45/231/21 (OI 14)ABG 7.31/45/231/21 (OI 14)

Low Vt and Low Vt and High PEEP High PEEP

HFOVHFOV

HFOV works!!!!HFOV works!!!!

3. Set up CV to achieve mPaw close to 20 cmH2O (e.g. PCV TV 6 ml/kg, 1:1, PEEP > 10 cmH2O, rate 20)

4. Wean conventionally (normalize I:E in 10% increments, reduce PEEP to <8, breathing trials)

5. Anticipate prolonged neuromuscular weakness

HFOV - Weaning StrategyHFOV - Weaning Strategycontinued...continued...

HFOV-Tools for SuccessHFOV-Tools for Success

• If considering HFOV, establish If considering HFOV, establish institutional criteria for considerationinstitutional criteria for consideration

• Adequate training of Adequate training of medical , medical , nursingnursing and and respiratory care staffrespiratory care staff

• Patience, patience, patience!!Patience, patience, patience!!

Clinical Strategies

• mPaw can be increased 1-2 cmH2O until optimal lung volume is reached, where an increase in SaO2 that allows a decrease in FiO2 to < 60%; CXR shows the diaphragms are at T-9.

• If starting with a frequency too high, unacceptable CO2 levels may result and suggest that the 3100B will not work.

• Remember that the PaCO2 may initially climb for many patients before it stabilizes and begins to come back down.

Amplitude Selection• Start at Power of “4” and adjust until the “wiggle” Start at Power of “4” and adjust until the “wiggle”

extends to the mid level of patient’s thigh.extends to the mid level of patient’s thigh.

• Adjust Amp in increments of 5 cm HAdjust Amp in increments of 5 cm H22OO

• Subjectively follow the wiggleSubjectively follow the wiggle

• Objectively follow transcutaneous COObjectively follow transcutaneous CO22

and Pand PaaCOCO22

• Remember, the goal is not to achieve ‘normal’ Remember, the goal is not to achieve ‘normal’ PPaaCOCO22 and pH, but to minimize VALI. and pH, but to minimize VALI.

“Wiggle Factor”• Reassess after positional changesReassess after positional changes

• If chest oscillation is diminished or absent consider:If chest oscillation is diminished or absent consider:

• decreased pulmonary compliancedecreased pulmonary compliance

• ETT disconnectETT disconnect

• ETT obstructionETT obstruction

• severe bronchospasmsevere bronchospasm

• If the chest oscillation is unilateral, consider:If the chest oscillation is unilateral, consider:

• ETT displacement (right mainstem)ETT displacement (right mainstem)

• pneumothoraxpneumothorax

Clinical Assessment

Sedation/Neuromuscular Blockade• Transitioning a patient from CMV to Transitioning a patient from CMV to

HFOV typically indicates that the patient’s HFOV typically indicates that the patient’s respiratory distress has worsened.respiratory distress has worsened.

• To facilitate ‘capturing’ the patient, To facilitate ‘capturing’ the patient, additional sedation may be required.additional sedation may be required.

• Neuromuscular blockade may be required.Neuromuscular blockade may be required.

• As the patient improves, discontinue the As the patient improves, discontinue the paralysis and wean the sedation as paralysis and wean the sedation as tolerated.tolerated.

Auscultation• Listen to the lung fields to primarily assess the Listen to the lung fields to primarily assess the

presence and symmetry of piston sounds.presence and symmetry of piston sounds.

• Asymmetry may indicate improper ETT Asymmetry may indicate improper ETT placement, pneumothorax, heterogeneous placement, pneumothorax, heterogeneous gross lung disease, or mucus plugging.gross lung disease, or mucus plugging.

• Pause the piston to perform a cardiac exam and Pause the piston to perform a cardiac exam and assess heart sounds.assess heart sounds.

• With the piston paused you have placed With the piston paused you have placed the patient in a CPAP mode and will have the patient in a CPAP mode and will have maintained Pmaintained Pawaw..

Chest Radiographs• Typically obtain a chest radiograph 1 hour Typically obtain a chest radiograph 1 hour

after initiating HFOV and then Q12-24 after initiating HFOV and then Q12-24 hours.hours.

• AssessAssess

• ETT placementETT placement• Rib expansion (goal is Rib expansion (goal is 9 ribs) 9 ribs)• Pneumothorax / airleak syndromePneumothorax / airleak syndrome• Change in lung diseaseChange in lung disease

Suctioning• Indications:Indications:

• Routine suctioning to ensure the ETT remains Routine suctioning to ensure the ETT remains patentpatent

• Frequency of suctioning varies by institution.Frequency of suctioning varies by institution.

• Our policy is every 12 to 24 hours and prn.Our policy is every 12 to 24 hours and prn.

• Decreased/absent wiggleDecreased/absent wiggle

• Possibly from mucus plugs/secretionsPossibly from mucus plugs/secretions

• Decrease in SDecrease in SppOO22 or transcutaneous O or transcutaneous O22 level level

• Increase in transcutaneous COIncrease in transcutaneous CO22 level level

• Suctioning de-recruits lung volumeSuctioning de-recruits lung volume

• May be minimized but not fully eliminated with May be minimized but not fully eliminated with closed suction system.closed suction system.

• May require a sustained inflation recruitment May require a sustained inflation recruitment maneuver following suctioning.maneuver following suctioning.

Sustained Inflation (LRM)• A sustained inflation is a lung recruitment maneuver.A sustained inflation is a lung recruitment maneuver.

• There are several ways in which to perform a LRM There are several ways in which to perform a LRM maneuver. maneuver.

• The piston is paused (thus leaving the patient in The piston is paused (thus leaving the patient in CPAP) and the PCPAP) and the Paw aw is increased by 8-10 cm His increased by 8-10 cm H22O for O for

30-60 seconds. 30-60 seconds.

• Once the LRM maneuver is completed, the piston is Once the LRM maneuver is completed, the piston is restarted.restarted.

• Potential complications:Potential complications:

• PneumothoraxPneumothorax

• CV compromise / altered hemodynamicsCV compromise / altered hemodynamics

When To Utilize A LRM Maneuver• When initiating HFOV to recruit lungWhen initiating HFOV to recruit lung

• After a disconnect or loss of FRC/PAfter a disconnect or loss of FRC/Pawaw

• After suctioning (even with a closed suction system)After suctioning (even with a closed suction system)

• Inability to wean FInability to wean FiiOO22

• When considering increasing PWhen considering increasing Pawaw

• A recruitment maneuver may recruit lung allowing A recruitment maneuver may recruit lung allowing you to maintain the baseline Pyou to maintain the baseline Pawaw and, thus, not and, thus, not

increase support.increase support.

Potential Complications of HFOV

• The higher intrathoracic pressures with HFOV may The higher intrathoracic pressures with HFOV may decrease RV preload and require volume decrease RV preload and require volume administration administration ± inotropic support.± inotropic support.

• PneumothoraxPneumothorax

• Migration/displacement of ETTMigration/displacement of ETT

• BronchospasmBronchospasm

• Acute airway obstruction from mucus plugging, Acute airway obstruction from mucus plugging,

secretions, hemorrhage or clotsecretions, hemorrhage or clot..

Clinical Assessment

• Chest x-raysChest x-rays• Obtain the first x-ray at the (1) Obtain the first x-ray at the (1)

hour mark to determine the hour mark to determine the lung volume at that time. Paw lung volume at that time. Paw may need to be re-adjusted may need to be re-adjusted accordingly.accordingly.

• Always obtain a CXR , if Always obtain a CXR , if unsure as to whether the unsure as to whether the patient is hyper-inflated or has patient is hyper-inflated or has de-recruited the lung.de-recruited the lung.

Clinical Assessment

• Chest x-raysChest x-rays• Stopping the piston is not Stopping the piston is not

necessary.necessary.• Do not remove the patient Do not remove the patient

from HFOV .from HFOV .• A respiratory therapist, nurse A respiratory therapist, nurse

of physician should be at of physician should be at bedside to assure the security bedside to assure the security of the airway and the patient’s of the airway and the patient’s positionposition..

Clinical Assessment• Chest Wiggle factor (CWF) must be Chest Wiggle factor (CWF) must be

evaluated upon initiation and followed evaluated upon initiation and followed closely after that. closely after that. • CWF absent or becomes diminished is CWF absent or becomes diminished is

a clinical sign that the airway or ET a clinical sign that the airway or ET tube is obstructed. tube is obstructed.

• CWF present on one side only is an CWF present on one side only is an indication that the ET tube has slipped indication that the ET tube has slipped down a primary bronchus or a down a primary bronchus or a pneumothorax has occurred. Check pneumothorax has occurred. Check the position of the ET tube or obtain a the position of the ET tube or obtain a CXR.CXR.

• Reassess CWF following any position Reassess CWF following any position change.change.

Clinical Assessment

• Cardiac Function:Cardiac Function:• Mean Arterial PressureMean Arterial Pressure• Pulse PressurePulse Pressure• Heart rateHeart rate• Capillary re-fillCapillary re-fill• CVPCVP• Swan-GanzSwan-Ganz• ECHO for cardiac ECHO for cardiac

functionfunction

Clinical Assessment

• AuscultationAuscultation• Heart sounds may be heard by Heart sounds may be heard by

stopping the piston stopping the piston • GI sounds may be heard by GI sounds may be heard by

stopping the piston for a brief stopping the piston for a brief momentmoment

• Lung sounds may be heard by Lung sounds may be heard by stopping the piston if patient is stopping the piston if patient is breathing spontaneously.breathing spontaneously.• Caution: Eliminate Caution: Eliminate disconnects to listen to the disconnects to listen to the lungs to prevent de-recruiting lungs to prevent de-recruiting the lungthe lung

Patient Care • Suctioning

– Indicated by decreased or absence CWF, decrease in O2 saturation, or an increase in TcCO2.

– Remember that each time the patient is disconnected from HFOV, they will potentially de-recruit lung volume.

– Closed suction catheters may mitigate de-recruitment, and you may have to adjust the

delta P to compensate for the attenuation of the delta P due to the right angle adapter

– It may be necessary to temporarily Paw

Patient Care • SuctioningSuctioning

• If using a closed suction If using a closed suction catheter remember to:catheter remember to:• Remove the suction Remove the suction catheter all the way from catheter all the way from the ET tube.the ET tube.

• Use both oximetry and Use both oximetry and TcCOTcCO22 to monitor the to monitor the patient for potential patient for potential disconnects. If the disconnects. If the patient disconnects patient disconnects between the adapter between the adapter and ET tube, there may and ET tube, there may be sufficient pressure to be sufficient pressure to prevent the low pressure prevent the low pressure alarm from sounding.alarm from sounding.

Patient Care• Bronchodilator Therapy Bronchodilator Therapy

• Patients who are actively wheezing or Patients who are actively wheezing or have RADhave RAD

• administration via bagging- try to administration via bagging- try to coordinate with suctioningcoordinate with suctioning

• IV terbutaline for patients who do not IV terbutaline for patients who do not tolerate disconnectstolerate disconnects

Patient Care

• May turn periodicallyMay turn periodically• Protect the airway when turning the Protect the airway when turning the

headhead• May lay on back, stomach, or sideMay lay on back, stomach, or side• May lay on any surface with the May lay on any surface with the

exception of an air mattress, i.e., gel, exception of an air mattress, i.e., gel, sheepskin, etc.sheepskin, etc.

• Caution turning frequently if you have Caution turning frequently if you have to disconnect from ventilator initiallyto disconnect from ventilator initially

Lung Recruitment with HFOV

PCV (mPaw 30)

HFOV (mPaw 35)

Tip: decreasing P (at constant power setting) may indicate improving lung volume

TTake Home Messagesake Home Messages

• Ventilation Strategies Ventilation Strategies dodo affect patient outcomes affect patient outcomes• Volume and pressure swings promote lung injury Volume and pressure swings promote lung injury

and mediator releaseand mediator release• Identify patients at risk for developing VILI Identify patients at risk for developing VILI

earlyearly• Before the fibroproliferative stage of ARDSBefore the fibroproliferative stage of ARDS

• Alternative support such as HFOV offers lung Alternative support such as HFOV offers lung protection that may improve outcomes for protection that may improve outcomes for patients with ARDSpatients with ARDS

SummarySummary

• Treatment of ARDS continues to evolveTreatment of ARDS continues to evolve• The study and understanding of contributing The study and understanding of contributing

factors to ARDS continuesfactors to ARDS continues• Past development and clinical study of HFOV has Past development and clinical study of HFOV has

given a good foundation to move forwardgiven a good foundation to move forward• HFOV has been shown to be effective tool in HFOV has been shown to be effective tool in

treatment of ARDStreatment of ARDS

YOUR ACTIONS ALWAYS INFLUENCE YOUR ACTIONS ALWAYS INFLUENCE SOMEONE!!SOMEONE!!

Questions??Questions??

Feel free to contact me at any time Feel free to contact me at any time

jason.higgins@viasyshc.comjason.higgins@viasyshc.com

HFOV Patient Care