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3100B Ventilator. 3100B Ventilator. Approved for sale outside the US in 1998 for patients weighing > 35 kg failing CMV Approved September 24, 2001 by the FDA for sale in the US. Pulmonary Injury Sequence. There are two injury zones during mechanical ventilation
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3100B Ventilator • Approved for sale outside the • US in 1998 for patients • weighing > 35 kg failing CMV • Approved September 24, 2001 • by the FDA for sale in the US
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 “Safe Window” Froese AB, Crit Care Med 1997; 25:906
High Frequency Ventilation • Advantages- • Enables ventilation above the “closing volume” with lower alveolar pressure swings. • Safe way of using “Super PEEP”.
Theory of Operation • Controls for Oxygenation and Ventilation are mutually exclusive. • 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.
Large Patient Strategies • When to consider HFOV use? • As with all candidates, the earlier the better • FiO2 >60, PEEP>10 with PaO2/FiO2 ratio<200 • Relative contra-indications • Obstructive lung disease • Elevated ICP
19 yo female - Pneumococcal pneumonia (Day 1) FiO2 100%, PEEP 20, PIP 60, SpO2 80%
19 yo female - Pneumococcal pneumonia (Day 2) FiO2 100% SpO2 - 78%
19 yo female - Pneumococcal pneumonia (Day 3) FiO2 100% and SpO2 70%
What if physiologic goals can’t be met using lung protective strategies? What if physiologic goals can’t be met using lung protective strategies?
Large Patient Strategies • ARDS • FiO2 matched • Paw 5 cmH2O above CMV • Power of 4.0 and then adjust for good CWF • Bias flow >20 lpm, higher if required to maintain Paw • Frequency determined by patient size and compliance • I-Time set to 33%
Oxygenation Strategies • Paw until you are able to FiO2 to 60% with a SaO2 of 90% • Avoid hyperinflation • Optimize preload, myocardial function • Ventilation Strategies • CWF- adjust Power Setting to target PaCO2 to between 45-55 mmHg • frequency by 1Hz increments if Amplitude is maximized • Induce cuff leak • allow permissive hypercarbia if indicated, keeping pH>7.25
HFOV Strategy • If CO2 retention persists, decreasing cuff pressure to allow gas to escape around the ET tube will move the fresh gas supply from the wye connector to the tip of the ET tube
Clinical Tips • Failure Criteria • Inability to decrease FiO2 by 10% within the first 24 hrs. • Inability to improve ventilation or maintain ventilation (after optimizing both frequency and amplitude) with PaCO2 < 80 with pH > 7.25. • A transcutaneous monitor is useful for trending CO2.
Clinical Assessment • Suctioning • Indicated by decreased or absence CWF, decrease in O2 saturation, or an increase in TcCO2. • Remember that each time the patient is disconnected from HFOV, they will potentially de-recruit lung volume. • Closed suction catheters may mitigate • de-recruitment • It may be necessary to temporarily Paw or perform recruitment maneuver
Derecruitment during Disconnect • Minimize suction • attempts • Use closed suction systems • Avoid unnecessary disconnects • May require RM or FiO2 to return SaO2 to baseline
Clinical Assessment • Chest Wiggle factor (CWF) must be evaluated upon initiation and followed closely after that. • CWF absent or becomes diminished is a clinical sign that the airway or ET tube is obstructed. • CWF present on one side only is an indication that the ET tube has slipped down a primary bronchus or a pneumothorax has occurred. Check the position of the ET tube or obtain a CXR. • Reassess CWF following any position change.
Clinical Assessment • Chest X-rays • Obtain the first x-ray at the (4) hour mark to determine the lung volume at that time. Paw may need to be re-adjusted accordingly. • Always obtain a CXR , if unsure as to whether the patient is hyper-inflated or has de-recruited the lung.
Clinical Assessment • Auscultation • Breath sounds-listen to the “intensity or sound” that the piston makes, it should be equal throughout. • Heart Sounds - stop the piston, (the patient is now on CPAP); listen to the heart sounds quickly, and restart the piston.
Clinical Tips • Weaning - • Wean FiO2 for arterial saturation > 90% • Once FiO2 is 60% or less, re-check chest x-ray and if appropriate inflation, begin decreasing the Paw in 1cmH2O increments • Wean Delta-P in 5 cmH2O increments for PaCO2 • Once the optimal frequency is found, leave it alone
Aerosol Therapy • Patients who are actively wheezing or have RAD • administration via bagging- try to coordinate with suctioning • IV terbutaline for patients who do not tolerate disconnects • promising new nebulizer technology
Practical Considerations • Humidification of bias flow accomplished with a traditional heated humidifier • Longer, flexible circuit allows patient positioning to prevent skin breakdown • Infection control issues
Managing Large Patients • Most patients will require heavy sedation and occasional neuromuscular blockers to be maintained on the 3100B.
HFOV Management • Guidelines for Transition to CMV • Paw <24 cmH2O or stalled • FiO2 < 50% or stalled • > 4 days HFOV • Return to CMV at similar Paw
3100B Rescue Trial • Fort P, et al. High-frequency oscillatory ventilation for adult respiratory distress syndrome-a pilot study. Crit Care Med 1997; 25:937-947 • Seventeen patients failing inverse ratio ventilation recruited for rescue with HFOV (3100B) • Predicted mortality > 80 percent
3100B Rescue Trial Fort P, Crit Care Med 1997; 25:937
3100B Rescue Trial Fort P, Crit Care Med 1997; 25:937
Multicenter Oscillator ARDS Trial • Prospective Randomized Controlled Trial of the SensorMedics 3100B HFOV for adults with ARDS • Follow-up to MOAT Pilot Rescue Trial • Early Entry, Non-Crossover Trial • Ten Institutions, North American Study • Derdak, AJRCCM 2002
Patient Demographics - Baseline HFOVCV N 75 73 Age 48 (17) 51 (18) Kg 78 (25) 81 (26) Apache II 22 (6) 22 (9) Sepsis 47% 47% Pneumonia 19% 16% Trauma 21% 18% Immune Compromised 12% 14% Airleak 16% 19% *NS
Ventilator Strategies - Goals • Normalize lung volume • Minimize peak ventilator pressures • Physiological targets included: • Oxygen Saturation > 88% • Delay weaning mPaw until FiO2 < 50% • pH > 7.15 • PaCO2 in the range of 40 – 70 mmHg
Primary Outcome: Status at 30d HFOV CMV N 75 73 Died 37%* 52% Alive + RS 41%** 22% Alive - no RS 21% 26% *P=0.098 ** HFOV 61% on vent vs CMV 73% on vent
MOAT2 - Secondary Outcomes HFOV(n=75) CV(n=73) Blood Pressure 0% 3% Airleak 9% 12% O2 Failure (OI >42 after 48h) 5% 8% pH < 7.15 5% 8% Mucus Plug 5% 4% *NS
MOAT2 Conclusions • Based on a study of 148 patients, use of HFOV for the treatment of severe ARDS resulted in an absolute reduction in mortality by 15%. • This reduction trend in mortality is still recognizable at six months in this same population. • There may also be benefits related to chronic lung change as reflected by the small but extended use of respiratory support in the conventional ventilation managed patients.
MOAT - Comparison with ARDSnet MOATARDSnet (6ml/kg) 30d mortality 37% 31% P/F 114 138 Paw 22 17 PEEP 13 9 OI 24 12 Sepsis 47% 27% ARDS NET, NEJM 2000
Compliance with LPV Day 0 Day 3 Day 7 Before publication 3% 6% 9% After publication 1% 3% 7% Changing Medical Practice • Changing Medical Practice is the Most Difficult Task • 6 ml/kg tidal volume ventilation for ARDS • Reasons of Non-Compliance • Reluctance to give up control to a protocol • Patient comfort • Acidosis • Oxygenation • Therefore: • Most patients with ARDS are not managed with LPV • HFOV has the potential to remove most barriers to use of LPV Rubenfeld GD et al ATS 2001
A Prospective Trial of HFOV in Adults with ARDS • Patient Population • 23 Adults 10F, 13M • Age 48 + 15 yrs • Weight 72 + 17 kg • Apache II 21 + 7 • LIS 3.4 + 0.6 • Diagnosis • Pneumonia/Sepsis 12 • Burn 5 • Bone Marrow Transplant 4 • Other 2 • Mehta et al. CCM 2001;1360-1369
A Prospective Trial of HFOV in Adults with ARDS • Patient Population • Prior Vent Days 6.1 + 5.6 days • PaO2/FiO2 (mm Hg) 100 + 41 • OI (FiO2 xPaw x 100/PaO2) 33 + 20 • Pressures during CMV • PIP (cmH2O) 37 + 4 • Paw 24 + 3 • PEEP 13.8 + 2.4 • Mehta et al. CCM 2001;1360-1369
A Prospective Trial of HFOV in Adults with ARDS • Outcomes • Reason for HFOV withdrawal • Successfully weaned 10 • Withdrawal of life support/death 11 • Technical problem 2 • ICU Survival 7/23 (30%) • Nonburn patients 7/17 (41%) • Burn patients 0/5 • Mehta et al. CCM 2001;1360-1369
A Prospective Trial of HFOV in Adults with ARDS • Days of Prior Ventilation • Non Survivors 7.8 + 5.8 days • Survivors 1.6 + 1.2 days • Mehta et al. CCM 2001;1360-1369
HFOV in Adults with ARDS • 42 patients failing CMV • Baseline P/F ratio = 99(+46) increased to 191(+121) after 24 hours without HFOV related adverse events. • 30 day mortality was 43% • Subset analysis showed higher 30 day mortality in patients on CMV>3 days(67%) M David et al ICM July,2003
Adjunctive Therapies - iNO • Post hoc analysis of 108 pediatric patients in a RCT with AHRF and iNO • Comparisons • HFOV plus iNO (n=14) • HFOV alone (n=12) • CMV plus iNO (n=35) • CMV alone (n=38) • Dobyns CCM 2002;30(11):2425
Conclusions • P/F ratio greatest in the HFOV plus iNO group at 4 and 12 hours • After 24 hours, both the HFOV plus iNO and HFOV alone resulted in greater P/F ratio improvement • Speculation that enhanced lung recruitment by HFOV enhances the effects of iNO on gas exchange
Adjunctive Therapies - Proning • Case report • 56 yo man d/w drug overdose and aspiration failing CMV and iNO • transitioned to HFOV plus iNO with improved ventilation • proning (q 6-8h) initiated due to worsening oxygenation • transitioned to CMV post 4 days, iNO weaned after 9 days • patient subsequently weaned and discharged • Anesthesiology 2001;95(3)797
Unresolved Issues • What is the best way to set Paw • What are the best recruitment strategies • How are hemodynamic parameters best assessed • How are aerosols best delivered • How to best predict responders • Does HFOV result in less VILI than a conventional lung protective strategy
Take Home Messages • Ventilation Strategies do affect patient outcomes • Volume and pressure swings promote lung injury and mediator release. • Identify patients at risk for developing VILI early- before the fibroproliferative stage • Alternative therapies such as HFOV may offer lung protection that may improve outcomes for patients with ARDS