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High Frequency Oscillatory Ventilation. Who Why When Where What How. ?. Neonatal Uses of HFOV. Hyaline membrane disease Persistent pulmonary hypertension Pulmonary interstitial emphysema (prevention and treatment) Sepsis / Pneumonia Congenital diaphragmatic hernia
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High Frequency Oscillatory Ventilation Who Why When Where What How ?
Neonatal Uses of HFOV • Hyaline membrane disease • Persistent pulmonary hypertension • Pulmonary interstitial emphysema (prevention and treatment) • Sepsis / Pneumonia • Congenital diaphragmatic hernia • Meconium aspiration syndrome
HFOV “Adult” Indications • ARDS • PCIRV • Paralysis • High FiO2 • Air Leak Syndrome • ECMO Candidates
Oxygenation Index OI = FiO2 x Paw PaO2 • Predictor of mortality • High value = bad outcome
MV won’t cure cancer HFOV won’t help with: COPD IPF Asthma Sarcoidosis HFOV Adult Patient Selection
HFOV Objectives • Support Lung • Oxygenation • CO2 Removal • Reduce Vent Induced Lung Injury
HFOV- When • Timing is everything • ASAP • 1-5 days of CMV • Not as a last resort
HFOV - Where? • ICU • Transport Limitation
HFOV “Where is the PEEP, tidal volume, graphics, and respiratory rate on this machine!?”……. AnonymousSurgeon
HFOV Design • Magnet • Bias Flow • CPAP with a wiggle • Expiratory Resistance • ACTIVE EXHALATION
Ventilator Settings • Hertz = BPM • Power (Amplitude P) • Paw • FiO2 • Bias Flow • Inspiratory time %
CO2 Removal • Hertz • Amplitude ( P)
Primary control of CO2 is by the stroke volume produced by the Power Setting
HFOV Settings: Inspiratory Time % • 33%= 1:2 I:E Ratio • Default • 50%= 1:1 I:E Ratio • Caution
Oxygenation • Paw • FiO2 • “What was that Oxygenation Index thing?”
Oxygenation • The Paw is used to inflate the lung • Paw = Lung Volume • Paw = PaO2 (usually) • Use blender to adjust FiO2
HFOV Controls PaO2 PaCO2
x Bias Flow CDP Control Balloon
HFOV - HowInitial Settings • FiO2 = 1.0 • Hz = 5.0 • Power setting = 5 • Paw = CMV + 5 • Insp Time = 33% • Flow = 30
Clinical Observations • Chest Wiggle Factor • CXR T8-9 • Pulse oximetery • TCO2 • ABG
Weaning • Wean FiO2 for Sat’s > 90% • When FiO2 60%, wean Paw by 1 • Return to CMV when: • FiO2 < 40% • Paw 15-20 • Amplitude < 40
HFOV: Conversion • Pressure limited ventilation • Delivered tidal volume ~6 ml/kg • PEEP ~10 cm H2O • Adjust for Pawsame as HFOV • FiO2 ~40 - 50%
Signs of Failure • OI > 42 at 48 hrs HFOV • Unable to wean FiO2 > 10% within 24 hours • Unable to PaCO2 <100 with pH 7.25
“On Patient” Issues • Inability to increase Paw • Fluctuating Paw • Changes in settings • Inappropriate patient response
Inappropriate Patient Response • Need for ETT suctioning • Low lung volume • Overdistended lung • Marginal cardiovascular status
Tricks • Prone positioning • ETT Leak • Bronchoscopy
HFOVCase Study Putting it all together
Pressure limited A/C FiO2 70% Vt 296 VE 9.2 RR 32 PEEP 12 Paw 24 PIP 36 I:E 1:1 Arterial blood gases pH 7.09 PaCO2 200 HCO3 49 PaO2 80 BE 26 SaO2 91 A-a gradient 169.1 OI 21 Day 16 CMV
“Oh yeah, did I mention…?” • 23 y/o female • ARDS • 3 CT • Prone • iNO • ECMO candidate
Indication: OI > 15 FiO2 > 60% PEEP > 10 PIP > 35 Paw > 15 Respiratory acidosis Inadequate alveolar ventilation Pt. Values: OI 21 FiO2 70% PEEP 12 PIP 36 Paw 24 pH 7.09 PaCO2 200 HFOV: Indications
Initial HFOV settings FiO2 100% Paw 30 Amplitude 62 Hz 5.0 It% 33% Bias flow 30 Arterial blood gases pH 7.26 *7.09 PaCO2 114 *200 PaO2 184 *80 HCO3 52 BE 22 SaO2 95.2 *ABG prior to HFOV HFOV: Initiation
HFOV settings FiO280% Paw 30 Amplitude 62 Hz 4.0 It% 50% Bias flow 30 Arterial blood gases pH 7.35 * 7.26 PaCO288 * 114 PaO2 104 * 88 HCO3 49 BE 22 SaO2 96 * ABG prior to changes in parameters Management: Strategy
HFOV settings FiO2 60% Paw 26 Amplitude 62 Hz 4.0 It% 50% Bias flow 30 Arterial blood gases pH 7.44 PaCO2 74 PaO2 97 HCO3 50 BE 24 SaO2 95 Management: 24 hours
HFOV settings FiO2 50% Paw 16 Amplitude 50 Hz 5.0 It% 40% Bias flow 40 Arterial blood gases pH 7.41 PaCO2 66 PaO2 83 HCO3 43 BE 16 SaO2 95 HFOV Day 7
Why did HFOV succeed? • Low pressure swings allowed air leaks to seal • Paw recruited collapsed lung