dasar ventilasi mekanik ag
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DASAR VENTILASI MEKANIK
ANANG ACHMADI, SpAn
ICU Bedah
RS Jantung Pusat Nasional
Harapan Kita - Jakarta
ObjectivesObjectives
• Describe types of breaths and modes
of mechanical ventilation
• Describe interactions between
ventilatory parameters and
modifications needed to avoid harmful
effects
• Describe types of breaths and modes
of mechanical ventilation
• Describe interactions between
ventilatory parameters and
modifications needed to avoid harmful
effects
Early ventilators
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Ventilator ~ Ventilator ~ ventilasiventilasi•• Ventilasi Ventilasi = = keluar masuknya udara dari atmosfer ke keluar masuknya udara dari atmosfer ke alveolusalveolus
•• Ventilator = Ventilator = menghantarkanmenghantarkan (delivery) (delivery) udaraudara/gas TEKANAN/gas TEKANANPOSITIF POSITIF ke dalam paruke dalam paru
•• Ventilasi semenit Ventilasi semenit = TV x RR (= TV x RR (frekuensi nafasfrekuensi nafas))
–– TV = 5-7 cc/TV = 5-7 cc/kgBBkgBB
–– RR = 10 –12 kali/RR = 10 –12 kali/menitmenit
•• Compliance = Compliance = Pengukuran dari elastisitas paru dan dindingPengukuran dari elastisitas paru dan dindingdadadada
–– Nilai Nilai compliance compliance mengekspresikan adanya perubahan mengekspresikan adanya perubahan volumevolumeakibat perubahan dari tekanan akibat perubahan dari tekanan (pressure)(pressure)
–– Compliance Compliance rendah rendah = “Stiff lung” - edema = “Stiff lung” - edema paruparu, , efusi efusi pleura,pleura,obstruksiobstruksi, , distensi distensi abdomen abdomen dan pneumotoraksdan pneumotoraks
–– Compliance Compliance tinggi tinggi = = penurunan elastisitas resistensi pada inspirasipenurunan elastisitas resistensi pada inspirasidan penurunan kemampuan mengeluarkan udara waktu ekspirasidan penurunan kemampuan mengeluarkan udara waktu ekspirasi(COPD)(COPD)
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Kriteria tradisional untuk bantuan ventilasi mekanikKriteria tradisional untuk bantuan ventilasi mekanik
35-45 > 60Ventilasi (PaCO2-mmHg)
25-65(FiO2 1.0) > 350P(A-aDO2) mmHg
75-100 (air)<60 dg FiO2 0,6Oksigenasi (PaO2-mmHg)
5-7 < 5TV (cc/kg)
10-20x/m > 35x/mMekanik (RR)
NORMAL RANGEINDIKASI VENTILASIPARAMETER
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TUJUAN KLINIS / INDIKASI PEMAKAIANTUJUAN KLINIS / INDIKASI PEMAKAIANVENTILASI MEKANIKVENTILASI MEKANIK
GAGAL NAFAS HIPOKSEMIK :
Reverse hypoxemia dgn pemberian PEEP dan konsentrasi O2tinggi (ARDS,edema paru atau pneumonia akut)
GAGAL NAFAS VENTILASI:
Reverse acute respiratory acidosis
- Koma : trauma kepala, encefalitis, overdosis, CPR
- Trauma med spinalis, polio, motor neuron disease
- Polineuropati, miastenia gravis
- Anesthesia (relaksan u/operasi, tetanus, epilepsi)
STABILISASI DINDING DADA:
Flail chest
MENCEGAH ATAU MENGOBATI ATELEKTASIS
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TUJUAN FISIOLOGISTUJUAN FISIOLOGIS
MEMPERBAIKI VENTILASI ALVEOLAR
MEMPERBAIKI OKSIGENASI ALVEOLAR(FiO2, FRC,V'A)
MEMBERIKAN PUMP SUPPORT ( MEWOB)
Consensus conference on mechanical ventilation, Int Care Med 1994,20:64-79
Indications for Mechanical Ventilation
Indications for Mechanical Ventilation
• Ventilation abnormalities– Respiratory muscle dysfunction
• Respiratory muscle fatigue• Chest wall abnormalities• Neuromuscular disease
– Decreased ventilatory drive– Increased airway resistance and/or
obstruction
• Ventilation abnormalities– Respiratory muscle dysfunction
• Respiratory muscle fatigue• Chest wall abnormalities• Neuromuscular disease
– Decreased ventilatory drive– Increased airway resistance and/or
obstruction
• Oxygenation abnormalities
– Refractory hypoxemia
– Need for positive end-expiratory pressure (PEEP)
– Excessive work of breathing
• Oxygenation abnormalities
– Refractory hypoxemia
– Need for positive end-expiratory pressure (PEEP)
– Excessive work of breathing
Indications for Mechanical Ventilation
Indications for Mechanical Ventilation
Types of Ventilator BreathsTypes of Ventilator Breaths
• Volume-cycled breath– “Volume breath”– Preset tidal volume
• Time-cycled breath– “Pressure control breath”– Constant pressure for preset time
• Flow-cycled breath– “Pressure support breath”– Constant pressure during inspiration
• Volume-cycled breath– “Volume breath”– Preset tidal volume
• Time-cycled breath– “Pressure control breath”– Constant pressure for preset time
• Flow-cycled breath– “Pressure support breath”– Constant pressure during inspiration
Modes of Mechanical Ventilation
• Consider trial of NPPV
• Determine patient needs
• Goals of mechanical ventilation– Adequate ventilation and oxygenation– Decreased work of breathing– Patient comfort and synchrony
Modes of Mechanical VentilationPoint of Reference:
Spontaneous Ventilation
Modes of Mechanical VentilationPoint of Reference:
Spontaneous Ventilation
Continuous Positive Airway Pressure (CPAP)
Continuous Positive Airway Pressure (CPAP)
• No machine breaths delivered
• Allows spontaneous breathing at elevated baseline pressure
• Patient controls rate and tidal volume
• No machine breaths delivered
• Allows spontaneous breathing at elevated baseline pressure
• Patient controls rate and tidal volume
Assist-Control VentilationAssist-Control Ventilation
• Volume or time-cycled breaths + minimal ventilator rate
• Additional breaths delivered with inspiratory effort• Advantages: reduced work of breathing; allows
patient to modify minute ventilation• Disadvantages: potential adverse hemodynamic
effects or inappropriate hyperventilation
• Volume or time-cycled breaths + minimal ventilator rate
• Additional breaths delivered with inspiratory effort• Advantages: reduced work of breathing; allows
patient to modify minute ventilation• Disadvantages: potential adverse hemodynamic
effects or inappropriate hyperventilation
Pressure-Support VentilationPressure-Support Ventilation
• Pressure assist during spontaneous inspiration with flow-cycled breath
• Pressure assist continues until inspiratory effort decreases
• Delivered tidal volume dependent on inspiratory effort and resistance/compliance of lung/thorax
• Pressure assist during spontaneous inspiration with flow-cycled breath
• Pressure assist continues until inspiratory effort decreases
• Delivered tidal volume dependent on inspiratory effort and resistance/compliance of lung/thorax
• Potential advantages– Patient comfort
– Decreased work of breathing
– May enhance patient-ventilator synchrony
– Used with SIMV to support spontaneous breaths
• Potential advantages– Patient comfort
– Decreased work of breathing
– May enhance patient-ventilator synchrony
– Used with SIMV to support spontaneous breaths
Pressure-Support VentilationPressure-Support Ventilation
• Potential disadvantages
– Variable tidal volume if pulmonary resistance/compliance changes rapidly
– If sole mode of ventilation, apnea alarm mode may be only backup
– Gas leak from circuit may interfere with cycling
• Potential disadvantages
– Variable tidal volume if pulmonary resistance/compliance changes rapidly
– If sole mode of ventilation, apnea alarm mode may be only backup
– Gas leak from circuit may interfere with cycling
Pressure-Support VentilationPressure-Support Ventilation
Synchronized Intermittent Mandatory Ventilation (SIMV)
Synchronized Intermittent Mandatory Ventilation (SIMV)
• Volume or time-cycled breaths at a preset rate
• Additional spontaneous breaths at tidal volume and rate determined by patient
• Used with pressure support
• Volume or time-cycled breaths at a preset rate
• Additional spontaneous breaths at tidal volume and rate determined by patient
• Used with pressure support
• Potential advantages– More comfortable for some patients
– Less hemodynamic effects
• Potential disadvantages – Increased work of breathing
Synchronized Intermittent Mandatory Ventilation (SIMV)
Synchronized Intermittent Mandatory Ventilation (SIMV)
Controlled Mechanical VentilationControlled Mechanical Ventilation
• Preset rate with volume or time-cycled breaths• No patient interaction with ventilator• Advantages: rests muscles of respiration• Disadvantages: requires sedation/neuro-
muscular blockade, potential adverse hemodynamic effects
• Preset rate with volume or time-cycled breaths• No patient interaction with ventilator• Advantages: rests muscles of respiration• Disadvantages: requires sedation/neuro-
muscular blockade, potential adverse hemodynamic effects
Inspiratory Plateau Pressure (IPP)Inspiratory Plateau Pressure (IPP)
• Airway pressure measured at end of inspiration with no gas flow present
• Estimates alveolar pressure at end-inspiration• Indirect indicator of alveolar distension
• Airway pressure measured at end of inspiration with no gas flow present
• Estimates alveolar pressure at end-inspiration• Indirect indicator of alveolar distension
Peak pressure Plateau pressure
Inspiration Expiration
PIP
Plateau pressure
• High inspiratory plateau pressure– Barotrauma – Volutrauma– Decreased cardiac output
• Methods to decrease IPP– Decrease PEEP– Decrease tidal volume
Inspiratory Plateau Pressure (IPP)Inspiratory Plateau Pressure (IPP)
Inspiratory Time: Expiratory Time Relationship (I:E ratio)
Inspiratory Time: Expiratory Time Relationship (I:E ratio)
• Spontaneous breathing I:E = 1:2
• Inspiratory time determinants with volume breaths– Tidal volume
– Gas flow rate
– Respiratory rate
– Inspiratory pause
• Expiratory time passively determined
• Spontaneous breathing I:E = 1:2
• Inspiratory time determinants with volume breaths– Tidal volume
– Gas flow rate
– Respiratory rate
– Inspiratory pause
• Expiratory time passively determined
I:E Ratio during Mechanical VentilationI:E Ratio during Mechanical Ventilation
• Expiratory time too short for exhalation– Breath stacking
– Auto-PEEP
• Reduce auto-PEEP by shortening inspiratory time– Decrease respiratory rate
– Decrease tidal volume
– Increase gas flow rate
• Expiratory time too short for exhalation– Breath stacking
– Auto-PEEP
• Reduce auto-PEEP by shortening inspiratory time– Decrease respiratory rate
– Decrease tidal volume
– Increase gas flow rate
Permissive HypercapniaPermissive Hypercapnia
• Acceptance of an elevated PaCO2, e.g., lower tidal volume to reduce peak airway pressure
• Contraindicated with increased intracranial pressure
• Consider in severe asthma and ARDS
• Critical care consultation advised
• Acceptance of an elevated PaCO2, e.g., lower tidal volume to reduce peak airway pressure
• Contraindicated with increased intracranial pressure
• Consider in severe asthma and ARDS
• Critical care consultation advised
Auto-PEEPAuto-PEEP
• Can be measured on some ventilators
• Increases peak, plateau, and mean airway pressures
• Potential harmful physiologic effects
• Can be measured on some ventilators
• Increases peak, plateau, and mean airway pressures
• Potential harmful physiologic effects
• Can be measured on some ventilators
• Increases peak, plateau, and mean airway pressures
• Potential harmful physiologic effects
• Can be measured on some ventilators
• Increases peak, plateau, and mean airway pressures
• Potential harmful physiologic effects
Auto-PEEPAuto-PEEP
Pediatric ConsiderationsPediatric Considerations
• Infants (< 5 kg)
– Time-cycled, pressure-limited ventilation
– Peak inspiratory pressure initiated at 18–20 cm H2O
– Adjust to adequate chest movement or exhaled tidal volume ~8 mL/kg
– Low level of PEEP (2–4 cm H2O) to prevent alveolar collapse
• Infants (< 5 kg)
– Time-cycled, pressure-limited ventilation
– Peak inspiratory pressure initiated at 18–20 cm H2O
– Adjust to adequate chest movement or exhaled tidal volume ~8 mL/kg
– Low level of PEEP (2–4 cm H2O) to prevent alveolar collapse
• Children– SIMV mode– Tidal volume 8-10 mL/kg– Flow rate adjusted to yield desired
inspiratory time• Infants 0.5–0.6 secs• Toddlers 0.6-0.8 secs• Older 0.8–1.0 secs
– Rate <18–20 breaths/min– PEEP 2–4 cm H2O
• Children– SIMV mode– Tidal volume 8-10 mL/kg– Flow rate adjusted to yield desired
inspiratory time• Infants 0.5–0.6 secs• Toddlers 0.6-0.8 secs• Older 0.8–1.0 secs
– Rate <18–20 breaths/min– PEEP 2–4 cm H2O
––
Pediatric ConsiderationsPediatric Considerations
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