Convention Modes of Mechanical Ventilation. DR.purwOKO

Convention Modes of Mechanical Ventilation

PurwokoSMF Anestesiologi & Terapi

IntensifRSUD Dr. Moewardi

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PRESSURE

TIME

Inspirasi Ekspirasi

PLATEAU PRESSURE

PEAK PRESSURE

0

KURVA NAFAS SPONTAN DAN VENTILASI MEKANIK

Respiratory Failure

• Tipe 1 : gagal nafas oksigenasi : Lung failure• Tipe 2 : gagal nafas ventilasi : Pump failure• Kombinasi tipe 1 dan 2• PaO2 < 60 mmHgdengan FiO2 60%

PaCo2 > 50 – 55 mmHgKecuali : alkalosis metabolik terkompensasi PPOK Shunting intrakardiak Aklimatisasi High altitude

Penanggulangan gagal nafas

Gagal nafas mengancam, Gagal nafas akut, Gagal

nafas mengancam nyawa?

Terapi oksigen : kanul, simple-mask, rbm, non-

rbm ventimask

Kausal (?) : antidotum

NIPPV

IPPV

IPPV

Terapi supportif (airway-pressure therapy)

Udara masuk karena ada perbedaaan tekanan

Diberikan sejumlah volume

Tekanan

Ada hubungan antara tekanan dan volume

P-V relationship : static mechanics

Ada hubungan antara tekanan dan flow :

dynamic mechanics

IPPV beberapa mode of ventilation

Conventional (primary)

modes

Dual – control modes

Biphasic pressure modes

Prinsip Kerja Ventilator (umum)

Pneumatik/ mekanik

Sumber gas : Oksigen dan compressed air

Katub inspirasi, katub ekspirasi, sirkuit ventilator

Elektronik/ mikroprosesor

Sistem kontrol, panel kontrol, monitor dan alarm

Sistem untuk sinkronisasi ventilator - pasien

Sumber Gas Ventilator

Suplai Sentral atau Lokal

Oksigen (penuh 130 atm, 1990 – 2200 psi)

Udara tekan (compression air)

Oxygen – Air mix (Blender) mengatur FiO2

Reducing valve outlet 45 – 55 psi

Working pressure 40 – 60 psi

Kondisi Gas Inspirasi

Harus cukup hangat (370 C)

Harus cukup lembab

1. Heat moisture exchanger (HME) : di Y-piece

Kendala HME : dead space , resistensi ,

hipotermia, air leaks, Vt sangat besar, sekret >>,

CO2 (k.i)

2. Heated humidifier (di dalam jalur inspirasi)

Dead space tak , Resistensi tak

Sistem Kontrol

Modus ventilasi mekanik ditentukan oleh kontrol

:

Fungsi awal inspirasi (Initiation / Trigger)

Akhir inspirasi (Limit / Target)

Awal ekspirasi (Cycle off)

Initiation / Trigger

• Control breath machine – triggered (time –

based)

• Assisted breath patient – triggered

Pressure – trigger (-2 cmH2O)

Flow – trigger (fixed, adjusted, flow by)

Cegah : *self – cycling auto triggering

*respons delay

Limit / Target

Dipakai untuk memberi nama Mode Target volume Volume control Target tekanan Pressure control

Target volume awasi pressureTarget pressure awasi volume

Faktor yang mempengaruhi target : resistesi tube, jalan nafas, compliance, aktifitas muskular, PEEPi

Cycle off

Target ditentukan oleh : volume (tidal volume)

dan pressure (airway pressure)

Cycle off ditentukan oleh :

Elapse time

Inspiratory flow rate

Target dan cycle off dapat saling terkait

Cycle off

Time-based cyclingDipakai pada : controlled atau assist – controlSetting Ti:

*langsung (sekian detik)*berdasar kombinasi f dan I:R ratio*berdasar peak flow rate dan volume tidal Flow-based cyclingDipakai pad: assist-spontaneous, fully spontaneousExpiratory trigger sensitivity : nilai absolut, 25%

dari peak flow rate, dapat diatur

Conventional mode of mechanical ventilation

VCV : Volume Control Ventilation

VAV : Volume Assist Ventilation

VACV : Volume Assist-Controlled Ventilation

IMV : Intermittent Mandatory Ventilation

SIMV : Synchronized IMV

PSV : Pressure Support Ventilation

PCV : Pressure Controlled Ventilation

VCV: Volume Controlled Ventilation

Ventilator memberikan nafas sesuai preset rate dan preset volume tidal

Tidak boleh ada nafas spontan Hanya pada pasien tanpa usaha nafas

Keuntungan : Otot pernafasan istirahatKerugian :Tidak ada interaksi ventilator – pasien

Perlu sedasi dan/ atau pelemas ototPotensial mengganggu hemodinamik

VAV: Volume Assisted Ventilation

Volume cycled (presed vol tidal) Vt diberikan sesuai preset rate Ventilator dpt meningkatkan nafas bila usaha

nafas pasien meningkatKeuntungan :

Pasien “menentukan” bantuan ventilasi Kerja nafas menurunKerugian : Gangguan hemodinamik, hiperventilasi

SIMV : Synchronized Intermittent Mandatory

VentilationMode untuk proses weaning (pasca bedah dll)Mulai dengan 10x, diturunkan bertahap Volume cycled (preset Vt) dan preset rate Nafas spontan boleh Vent’tor memberi nafas sinkron dg awal inspirasi Bisa digabung dengan pressure supportKeuntungan : interaksi vent – pasien >

Efek pada hemodinamik <Kerugian : Kerja nafas dapat meningkat

PSV : Pressure Support Ventilation

Mode untuk proses weaning (FRC rendah, nafas cepat/dangkal, kelelahan otot)

Mulai dengan 20 cm H2O, diturunkan bertahapMemberikan bantuan inspirasi spontanMeningkatkan usaha nafas pasienPasien mengendalikan: rate, insp. Time, aliran gas dan VtDapat digunakan bersama SIMV

Keuntungan: Pasien > nyaman, interaksi pasien – vent baik, kerja nafas menurun.Kerugian: back up hanya alarm apnea, toleransi psn bervariasi

PCV: Pressure Controlled Ventilation,

IRV: Inverse Ratio Ventilation Machine – triggered, preset pressure, time cycled

Controlled atau Assisted bergantung effort PIP (Peak Inspiratory Pressure) “dibatasi” Setting tepat flow rate, Ti dan mean-Paw IVR

(1:1 atau 2:1) untuk inflasi alveolar, rekruitmen dan oksigenasi

Perlu sedasi atau pelemas otot Hati2 auto-PEEP atau PEEPi Open Lung Concept pada ARDS

CPAP: Continuous Positive Airway Pressure

Mode untuk proses weaning (sebelum T-piece)

Bukan mode “asli”

Nafas spontan

Tekanan base line tinggi

Rate dan Vt bergantung pada usaha nafas pasien

PEEP Dapat dipasang pada semua mode of ventilation FRC meningkat Mencegah kolaps alveoli yang patent(<10cmH2O)

Mengembangkan alveoli yang kolaps (>10cmH2O) Pada edema paru Mendistribusi extravascular lung water Memperbaiki FRC Lung compliance, difusi oksigen

Aplikasi PEEP Mulai 5cmH2O ditingkatkan 2 – 3cmH2O

Pantau tanda vital, PaO2

Efek samping Barotrauma Hipotensi Penurunan curah jantung Peningkatan dead space alveolar Perburukan oksigenasi

Pedoman Memulai Ventilasi Mekanik

Pilih mode paling familiar FiO2 mulai 100% turun bertahap, SpO2 > 92%

Vt awal 8 – 10 cc /kgBB RR dan MV sesuai kebutuhan klinik I/E 1:2 PEEP (mengurangi FiO2, membantu oksigenasi

mis: pada edema paru diffus) Hindari tek inspirasi terlalu tinggi (kurangi flow rate atau

volume tidal) Hb, curah jantung, sat. oksige darah arteri Sedasi, analgesi, perubahan posisi Bila hipotensi, ingat tension pneumotorak

Sasaran Ventilasi Mekanik

Oksigenasi : FiO2 awal tinggi bukan masalah Pertahankan saturasi O2 > 92% Peran PEEPVentilasi : Sesuaikan dengan kebutuhan klinik Nilai pH dan PaCO2 bersama-sama Perlu hipo/ hiperventilasi pada keadaan khusus :

Acidemia, hiperkapnia kronik

Ventilator Induced Lung Injury

Potential to Produce or Augment Injury High Peak Inflation Pressures Alveolar Overdistention Shear Forces Alveolar Recruitment/ Derecruitment PEEP has Beneficial Role Correct Ventilator Management Strategy

Favorably Impacts Outcome

Biotrauma Ventilatory strategies with high tidal volumes and

low PEEP can lead to bacterial translocation from the lung into the systemic circulation

Nahum A, et al.Crit Care Med 1997; 25: 1773-1743 Verbugge SJ, et al.Intensive Care Med 1998; 24: 172-177 High tidal volume low PEEP ventilation has been

shown to increase cytokines in BAL fluid and in the systemic circulation

Ranieri VM, et al.JAMA 1998. 282: 54-61

Lung Protective Strategies by Pflex

Keep PEEP above llower Pflex

to avoid alveolar

underrecruitment

Keep tidal breathing between upper and lower Pflex to avoid

alveolar overdistension

Ventilatory Strategy for ARDSPplt > 35 cmH2O or High FiO2 with SaO2 < 90%

PC 1:1 Higher PEEP & Lower VT

Sedation & Paralysis

SaO2 < 90%Pplt > 35 cmH2O

SaO2 > 90%Pplt > 35 cmH2O

SaO2 < 90%Pplt < 35 cmH2O

PCIRVPermissive Hypercapni

aPEEP

Jenis Pernapasan Kendali

Breath Type Initation (Tigger)

Limit (Target)

Cycle-off

Mandatory Mesin Mesin Mesin

Assisted Pasien Mesin Mesin

Supported Pasien Mesin Pasien

Spontaneous Pasien Pasien Pasien

Aplikasi Fungsi Pernafasan dengan Ventilator

Fungsi Mode Parameter primer Keterangan

Initation Control Interval waktu Trigger: mesin

Assist Ambang tek (-) jalan nafas Trigger: mesin

Limit Volume Preset volume tidal Variasi tek jln nafas

Pressure Tekanan jalan nafas tercapai

Variasi volume tidal

Cycle-off Volume Volume preset tercapai

Pressure Tekanan preset tercapai

Time Interval waktu terlewati Ins. Pause (aliran nol)

Flow Menurun sp laju aliran minimal

Pola aliran inspirasi

Penutup Mode apapun yang dipakai, VM hanyalah bantuan

fisiologik, bersifat sementara

Perbaikan terhadap penyebab gangguan tersebut merupakan tujuan utama

Hendaknya selalu diingat efek samping yang tidak diinginkan

Dalam memenuhi oksigenasi tidak hanya ventilasi tetapi perfusi juga berperan sangat penting

Gunakan ventilator yang paling familiar

Mech. Ventilation is still more art than science

Lesson from Protective Ventilation Strategy

PEEP to open the alveoli Low VT to prevent over distention

Pplat < 30 cm H2O Higher respiratory rate to

overcome acidosis permissive hypercapnea

Frequent recruitment

APRV

APRV Is similar to CPAP in that the pt. is allowed to

breathe spontaneously without restriction

Combines two separate levels of CPAP and the pt. may breathe spont. From both levels

Periodically, pressure is dropped to the lower level, reducing mean airway pressure

During spont, expir. the CPAP is dropped (released) to a lower level which simulates an effective axhalation and CO2 removal

Problem with Older Modes

More work of breathing

Less patient comfort

Either Volume or Pressure is not assured

less security

Need more frequent adjusment

Volume – Assured Pressure Support (VAPS)

• Parameters set : Pressure limit = plateau pres. seen during VC Respiratory rate Peak flow rate PEEP FiO2

Trigger sensitivity Minimum tidal volume

Volume – Assured Pressure Support (VAPS)

Amato et al. Chest 1992; 102: 1225 –

1234

VAPS vs AC

Lower WOB

Lower Raw

Less PEEPi

Pressure – Regulated Volume Control

Pressure limited

Time cycled

Adaptive pressure ventilation (Galileo)

Autoflow (Evita 4)

Automatically adjust pressure support level to

minimum needed to maintain constant set TV

Automode

Siemens Servo 300A

Combines volume Support and PRVC into a

single mode

Switches between PS and PC, with pt effort

determining whether the breath will be VS or

PRVC

Automode

If pt makes no effort, you get PRVC

As pt begins to breathe spontaneously, switch

to VS

Mean airway pressure could become too low

No evidence to advocate its use

Adaptive Support Ventilation

Hamilton Galileo

Dual control, breath to breath mode

Pressure limit of spontaneous and mandatory

breaths is constantly adjusted

Based on idea that a pt will breathe a TV and

rate that minimizes elastic and resistive loads


Parameters set: Ideal BW High pressure alarm PEEP FiO2

Flow cycle variable (10 – 40%) of initial peak flow, and % volume control (20 – 200%)

Ventilator delivers as volume control 100 ml/kg/min for adults 200 ml/kg/min for childres


If pt makes no effort to breathe, ventilator

delivers required minute ventilation as PC

If pt starts to breathe spontaneously,

ventilator gradually reduces number of

mandatory breaths and lower pressure

support level as necessary to keep minute

ventilation above the minimum setting


If pt spontaneous TV is more than the

target and rate is less, the pressure limit

is reduced and rate of mandatory

breaths is increased

If TV > target and rate > target,

pressure limit is lowered and number of

mandatory breaths is reduced


1. Potential Advantages matches ventilation to lung condition quicker, automatic weaning decreased risk of lung damage2. Potential Disadvantages leaks my defeat algorithm operator must select appropriate % of minute

ventilation to support deadspace may cause problems

Automatic Tube Compensation

Drager Evita 4

Overcome WOB added by artificial

airways

Improved patient/ ventilator synchrony by

providing variable fast inspiratory flow


Due to varying inspiratory flow rates, no

single level of pressure support can

actually fully compensate for WOB

caused by ETT

Autotube uses known static resistence

for each size and type of ETT/ tracheal

tube, and measures flow rates


Pressure is applied and continuously

adjusted proportional to resistance

Tracheal pressure (cm H2O) = proximal

airway pressure (cm H2O) – tube

coefficient (cm H2O/L/sec) x flow2 (L/min)


Potential Advantages simulates breathing without tube decreases patient work of breathing Potential Disadvantages actual tube resistance may change- secretions, kinking May not simulate actual conditions- swelling after extubation

Proportional Assist Ventilation

The goal is to maintain a constant fraction of

work per breath done by ventilator

If ventilator is set to give 80% volume and flow

assist, if the tidal volume increases, the pressure

increases to keep the amount of patient work

constant

Proportional Assist Ventilation

Potential Advantages support matched to need- Only abnormal load is supported better machine – patient synchrony- Theoretically the best mode Potential Disadvantages leaks defeat ventilator algorithm no ventilation if patient stops breathing

Conclusion

Modern ventilators offer several potentially

very useful new modes designed for variety

of purposes

Most of newer modes offer the benefits of

pressure-limited breaths with the security of

an assured minimum tidal volume

More patient comfort with less patient work

Mechanical Ventilation

Mechanical Ventilation physiologically supportive not

Ethiologically curative

Other Therapy

Functional Autonomy re-established

Therapy

Goal

Tim

e

Str

ate

gy

Primum non nocere

Convention Modes of Mechanical Ventilation. DR.purwOKO

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