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

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Presentation on theme: "When the smallest thing matters SLE5000 HFOV Presented by SAYU ABRAHAM."— Presentation transcript:

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

2 When the smallest thing matters 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 HFVs are frequently described by their delivery method, they are usually classified by their exhalation mechanism (active or passive).

3 When the smallest thing matters Differences between HFOV and CMV CMVHFOV Rates0 - 150180 - 900 Tidal Volume4 - 20 ml/kg0.1 - 5 ml/kg Alv Press0 - > 50 cmH 2 O0.1 - 5 cmH 2 O End Exp VolLowNormalized

4 When the smallest thing matters HFV Gas Exchange Henderson first published his findings in 1915, assessing dead space relationship in ventilation. He stated, there may easily be a gaseous exchange sufficient to support life even when Vt is considerably less than dead space.

5 When the smallest thing matters High Frequency Ventilation Types of HFVs Approved for use in both Neonates and Pediatrics SLE5000 HFOV SensorMedics 3100A HFOV Bird Volumetric DiffusiveHFPPV Types of HFVs Approved for use in Neonates Only Bunnell Life Pulse HFJV Infrasonics Infant Star (discontinued)HFFI

6 When the smallest thing matters 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

7 When the smallest thing matters HFOV: SLE 2000 Insp. Line Resistor (Trigger sensibility) Exp. Valve Block Bias flow 5l/min Rotating jet Peep adjustment

8 When the smallest thing matters Indications of HFOV Neonatal RDS/HMD Air leak syndromes MAS PPHN CDH

9 When the smallest thing matters Ventilator Induced Lung Injury Barotrauma Volutrauma Stretch Injury Biochemical Injury

10 When the smallest thing matters 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:

11 When the smallest thing matters 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.

12 When the smallest thing matters Ventilator Induced Lung Injury Barotrauma Air leaking into pleural space Air leaking into interstitial space (PIE) Tearing at Bronchio- Alveolar Junction as lung is recruited and allowed to collapse Most occurs in dependent lung zones (transition zone)

13 When the smallest thing matters Effect of 45 cmH 2 O PIP Control 5 min 20 min

14 When the smallest thing matters Ventilator Induced Lung Injury Stretch Injury Alters capillary transmural pressures Changes in transmural pressure causes breaks in capillary endo and epithelium Increases leak of proteinacious material Promotes Atelectasis

15 When the smallest thing matters Ventilator Induced Lung Injury Volutrauma Caused by cycling of the lung (change in surface area), independent of pressure required Alters Surfactant function Promotes Atelectasis Increases capillary leak of proteinacious material Promotes Atelectasis Dreyfuss,D ARRD 1988;137:1159

16 When the smallest thing matters Ventilator Induced Lung Injury Premature baboon model Coalson J. Univ Texas San Antonio

17 When the smallest thing matters Ventilator Induced Lung Injury Premature baboon model Coalson J. Univ Texas San Antonio

18 When the smallest thing matters 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

19 When the smallest thing matters Ventilator Induced Lung Injury 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

20 When the smallest thing matters HFOV

21 When the smallest thing matters Theory of Operation Oxygenation is primarily controlled by the Mean Airway Pressure (Paw) and the FiO 2 Ventilation is primarily determined by the stroke volume (Delta-P) and the frequency of the ventilator.

22 When the smallest thing matters HFOV effectively decouples: Oxygenation & Ventilation

23 When the smallest thing matters HFOV Principle: Pressure curves CMV / HFOV

24 When the smallest thing matters Principles of the SLE5000 HFOV Super-CPAP system to maintain lung volume

25 When the smallest thing matters 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

26 When the smallest thing matters 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

27 When the smallest thing matters Oxygenation The Paw is used to inflate the lung and optimize the alveolar surface area for gas exchange. Paw = Lung Volume

28 When the smallest thing matters CDP = Lung Volume CT 1 CT 2 CT 3 P aw = CDP Continuous Distending Pressure

29 When the smallest thing matters Open up the lung up and keep it open! Burkhard Lachmann, 1992

30 When the smallest thing matters Primary control of CO 2 is by the stroke volume produced by the Delta P Setting.

31 When the smallest thing matters Regulation of stroke volume The stroke volume will increase if –The amplitude increases (higher delta P) Stroke volume

32 When the smallest thing matters Secondary control of PaCO 2 is the stroke volume produced by the set Frequency.

33 When the smallest thing matters Regulation of stroke volume The stroke volume will increase if –The amplitude increases (higher delta P) –The frequency decreases (longer cycle time) Stroke volume

34 When the smallest thing matters CDP=FRC= Oxygenation HFOV Principle: +++++ -- --- Amplitude Delta P = Tv = Ventilation I E HFOV = CPAP with a wiggle !

35 When the smallest thing matters Pressure transmission Gerstmann D.

36 When the smallest thing matters Airway Pressure Transmission HFOV : Transmission ET TubeTracheaAlveolus CDP / MAP = Lungvolume = Oxygenation Pressure Amlitude Delta P = TV = Ventilation I E +++ ++ + ++ + + _ __ ___ _ _ _

37 When the smallest thing matters HFOV Mechanisms of Gas Transport

38 When the smallest thing matters 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

39 When the smallest thing matters 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

40 When the smallest thing matters 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.

41 When the smallest thing matters Continued……… Evaluation of lung expansion on CXR Check capillary refill, skin color and temperature Comparing central and peripheral pulses Monitoring of ECG Tracing Frequent CXRs 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

42 When the smallest thing matters 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


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