When the smallest thing matters SLE5000 HFOV Presented by SAYU ABRAHAM.

When the smallest thing matters

SLE5000HFOV

Presented

by SAYU ABRAHAM


High Frequency Ventilation

• Defined by FDA as a ventilator that delivers more than 150 breaths/min.

• Delivers a small tidal volume, usually less than or equal to anatomical dead space volume.

• While HFV’s are frequently described by their delivery method, they are usually classified by their exhalation mechanism (active or passive).


Differences between HFOV and CMV

CMV HFOV

Rates 0 - 150 180 - 900

Tidal Volume 4 - 20 ml/kg 0.1 - 5 ml/kg

Alv Press 0 - > 50 cmH2O 0.1 - 5 cmH2O

End Exp Vol Low Normalized


High Frequency Ventilation• Types of HFV’s Approved for use in both Neonates and

Pediatrics• SLE5000 HFOV• SensorMedics 3100A HFOV• Bird Volumetric Diffusive HFPPV

• Types of HFV’s Approved for use in Neonates Only• Bunnell Life Pulse HFJV• Infrasonics Infant Star (discontinued) HFFI


SLE5000

• Electrically powered, electronically controlled

• Conventional and HFOV ventilator

• Paw of 3 - 35 mbar• Delta P from 4 – 180

mbar• Frequency of 3 - 20 Hz• I:E Ratio 1:1• Active exhalation


“HFOV”:SLE 2000

Insp. Line Resistor (Trigger sensibility)

Exp. Valve Block

Bias flow 5l/min

Rotating jet

Peep adjustment


Indications of HFOVNeonatal

RDS/HMDAir leak syndromes

MASPPHNCDH


Ventilator Induced Lung Injury

• Barotrauma

• Volutrauma

• Stretch Injury

• Biochemical Injury


Absence of Surfactant

Atelactasis

Tidal Breathing

High Distending Pressures

Airway Stretch / Distortion

Cellular Membrane Disruption

Edema / Hyaline Membrane Formation

Higher FIO2 , Volumes, Pressures

Volutrauma, Barotrauma, Biotrauma

PIE, BPD

Pulmonary Injury Sequence of the neonatal patient:


Pulmonary Injury Sequence

• If we cannot prevent the injury sequence , then the target goal is to interrupt the sequence of events.

• High Frequency Oscillation does not reverse injury, but will interrupt the progression of injury.



Premature baboon model

Coalson J. Univ Texas San Antonio


Pulmonary Injury Sequence

• There are two injury zones during mechanical ventilation• Low Lung Volume

Ventilation tears adhesive surfaces

• High Lung Volume Ventilation over-distends, resulting in “Volutrauma”

• The difficulty is finding the “Sweet Spot”

Froese AB, Crit Care Med 1997; 25:906



• HFOV with Surfactant as Compared to CMV with Surfactant in the Premature Primate– HFOV resulted in

• Less Radiographic Injury

• Less Oxygenation Injury

• Less Alveolar Proteinaceous Debris

Jackson C AJRCCM 1994; 150:534

Alveolar Protein

0%

5%

10%

15%

20%

25%

30%

CM

V

CM

V-S

HF

OV

HF

OV

-S

Mode

Per

cen

t D

ebri

s


HFOV


Theory of Operation

• Oxygenation is primarily controlled by the Mean Airway Pressure (Paw) and the FiO2

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


HFOV effectively decouples:

Oxygenation & Ventilation


HFOV Principle:Pressure curves CMV / HFOV


Principles of the SLE5000 HFOV

“Super-CPAP” system to maintain lung volume


Optimized Lung Volume Strategy:

Increase Lung Volume above critical opening pressure to the Optimum and keep it there in

Inspiration and Expiration.

Benefits: - homogenous gas distribution- reduced regional atelectasis- maximized gas exchange area and pulmonary blood flow

- better matching of ventilation/perfusion- reduction of intrapulmonary shunting - reduced Oxygen exposure


Optimized Lung Volume Strategy:

Decrease Tidal Volumes to less or equal to dead space and increase frequency.

Benefits: - enhanced gas exchange due to combined gas transport mechanisms

- no excessive volume swings- reduced regional over-inflation and stretching

- reduced Volutrauma


Oxygenation

• The Paw is used to inflate the lung and optimize the alveolar surface area for gas exchange.

• Paw = Lung Volume


CDP =Lung Volume

CT 1 CT 2CT 3

Paw = CDPContinuousDistendingPressure


“Open up the lung up

and keep it open!”

Burkhard Lachmann, 1992


Primary control of CO2 is by the stroke volume produced by the Delta P Setting.


Regulation of stroke volume

• The stroke volume will increase if– The amplitude increases (higher delta

P)

Stroke volume


Secondary control of PaCO2 is the stroke volume produced by the set Frequency.


Regulation of stroke volume

• The stroke volume will increase if– The amplitude increases (higher delta

P) – The frequency decreases (longer cycle

time)Stroke volume


CDP=FRC=Oxygenation

HFOV Principle:

+ + + + +

- - - - -

AmplitudeDelta P =Tv =Ventilation

I

E

HFOV = CPAP with a wiggle !


Pressure transmission

Gerstmann D.


Airway Pressure Transmission HFOV :

Transmission

ET Tube Trachea Alveolus

CDP / MAP= Lungvolume= Oxygenation

Pressure

AmlitudeDelta P =TV =Ventilation

I

E

+ + +

+ + ++ + + +

_ _ _

_ _ __ _ _


HFOV Mechanisms of Gas Transport


Mechanisms of HFOV Gas Exchange

• There are six mechanisms of gas exchange during HFOV– Convective

Ventilation– Asymmetrical Velocity

Profiles– Taylor Dispersion– Pendeluft– Molecular Diffusion– Cardiogenic Mixing


Practical preparation

• Avoid leak around the E.T tube• Tc PO2,CO2,Pulse oxymeter and invasive

blood pressure monitoring• Baseline CXR• Optimize blood pressure and

perfusion(volume replacement and inotropes)

• Muscle relaxant/sedation• Reusable low compliance circuits must be

used


NURSING CARE• Perform through suction before connecting to the

oscillator.• Assess patient upon commencement of HFOV.Monitor

vital signs, chest wiggle must be evaluated upon initiation and followed closely thereafter. If chest wiggle diminishes it may be ETtube moved or obstructed. Chest wiggle on one side indicates patient developed pneumothorax,thus chest wiggle assessment should be performed after repositioning.

• Auscultation the chest by putting in standby mode.• A closed suction should be used. It is not necessary to

disconnect the patient to suction as this will potentially derecruit lung volumes.

• The point at which the ET tube is cut and secured at lips should be initially noted this measurement is reference.


Continued………

• Evaluation of lung expansion on CXR• Check capillary refill, skin color and

temperature• Comparing central and peripheral pulses• Monitoring of ECG Tracing• Frequent CXR’s blood gases in initial

stabilization period• Optimal lung volume for oxygenation is 8-9

rib inflation• Blood pressure and perfusion should be

optimized prior to HFOV,any volume replacement should be completed and inotropes commenced if necessary


Continued………

• Muscle relaxants are not indicated since spontaneous respiratory effort will be a clinical indicator of adequacy of ventilation

• Sedation with opiates is often indicated

THANKYOU

When the smallest thing matters SLE5000 HFOV Presented by SAYU ABRAHAM.

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Transcript of When the smallest thing matters SLE5000 HFOV Presented by SAYU ABRAHAM.