venovenous Flashcards
severe mortality associated with ARDS with conventional ventilation
- severe respiratory failure and acute respiratory distress syndrome (ARDS) ranges from 40% to 50% with conventional medical management.
GENERAL goals of lung-protective ventilation
lung-protective ventilation seeks to:
- avoid barotrauma (by monitoring transpulmonary pressure and avoiding high airway pressures),
- avoid volutrauma (by avoiding excessive tidal volumes, thereby allowing the lung to rest),
- avoid atelectotrauma (by maintaining adequate positive end-expiratory pressure (PEEP)]
- avoid oxygen toxicity (by decreasing ventilator oxygen levels when PEEP is adequate)
typical initial circuit settings for VV-ECMO
- FIO2 (fraction of inspired oxygen) is set at 1.0
- sweep gas-flow rate of 2–5 L/min (sweep up to 15 L/min for PACo2 < 40)
- evolutions per minute (RPM) set to achieve 50–80 mL/kg IBW /min of flow.
- Maintain SaO2 80-85 (as long as pt doing OK - SVO2, lactate nl )
Typical initial flow of VV-ECMO
revolutions per minute (RPM) set to achieve 50–80 mL/kg/min of flow.
Currently recommended ventilator settings for initiation of VV ECMO
- tidal volume to 4–6 mL/kg of predicted body weight
- plateau pressure of ≤25 cmH2O,
- with a PEEP of 10 cmH2O
Initial tidal volume for patients on VV
tidal volume to 4–6 mL/kg of predicted body weight
Goal Plateau pressure for patients on VV
plateau pressure of ≤25 cmH2O,
Goal PEEP for patients on VV
with a PEEP of 10 cmH2O
in VV-ECMO what are the key determinants of peripheral oxygen saturation?
- the oxygen fraction of the circuit
- the ratio of ECMO flow to native cardiac output
- metabolic demand
- native lung function
- Recirculation
Initial sweep for patients on VV-ECMO
sweep gas-flow rate of 2–5 L/min (sweep up to 15 L/min for PACo2 < 40)
Goal initial SaO2 for patients on VV ECMO
Maintain SaO2 80-85 (as long as pt doing OK - SVO2, lactate nl )
Levy protocol - for SaO2 < 88%
initial things to check
Check CXR - cannula malposition/ Recirculation
Circuit for filter dysfunction
Lung complications?
Low pre-filter SaO2?
Levy protocol - for SaO2 < 88%
- cannula OK, no recirc
- No lung issues
- Prefilter SAO2 Ok
what next?
increase the ECMO flow to 6-7 L
Levy protocol persistent SAO2
Flow at 7 L.min
CIrcuit OK
No lung complications
what next?
Check Hgb, transfuse to HgB > 10
Persistent hypoxemia, flow, circuit, HgB already corrected what to check for ?
QECMO / QCO < 60%
if present, consider:
Hypoxemia or Esmolol
The classic signs of recirculation
The classic signs of recirculation are low SaO2 and high SpreO2 (preoxygenator saturation).
The formula for recirculation:
Recirculation (%) = (SpreO2 – SvO2) / (SpostO2 – SvO2) × 100
“30-30-10-10” approach
“30-30-10-10” approach Goal ventilator settings
- FIO2 : 30
- PPlat < 30 cmH20
- PEEP: 10
- RR: 10
Labs used to evaluate the amount of hemolysis in ECMO circuit.
-
Lactate dehydrogenase
- can indicate circuit-induced hemolysis (only if sepsis is not present)
- Routine testing for free plasma hemoglobin:
- more accurately determines if hemolysis is occurring in the circuit.
From what material is the oxygenator membrane constructed ?
polymethylpentene
- less hemolysis
- less pressure drop
- less plasma leakage
- has a longer lifespan than materials used in earlier oxygenators
Normal-pressure drop across the Oxygenator membrane?
At what level pressure drop is changing the oxygenator strongly suggested ?
A normal pressure drop across a membrane is <50 mmHg;
a change in pressure >100 mmHg strongly suggests an obstruction within the oxygenator
Incidence of RV failure with ARDS ?
The incidence of RV failure related to ARDS has been reported to be 10–25%.
Treatment of RV failure on VV-ECMO
- Treat Pulmonary Hypertension
- hypoxemia
- hypercarbia
- acidemia cause
- pulmonary vasodilators
- inotropes
- diuretics.
initial treatments of Pulmonary Hypertension
Treat Pulmonary Hypertension
- hypoxemia
- hypercarbia
- acidemia cause
Mortality associated with severe ARDS
up to 45%
Does the patient fulfill oxygenation and/or ventilation criteria?
Does the patient fulfill oxygenation and/or ventilation criteria?
- • On FiO2 ≥ 80%, PEEP ≥ 10 cmH2O, VT ≤ 6ml/kg (PBW)
- • PaO2/FiO2 < 50 mmHg for > 3 hours
- • PaO2/FiO2 < 80 mmHg for > 6 hours
- • pH < 7.25, PaCO2 ≥ 60 mmHg with RR 35/min for > 6 H
ELSO specific criteria for VV-ECMO
- Mortality > 80%;
- PaO2/FIO2 < 80 mm Hg with FIO2 > 90%,
- Murray score 3-4;
- CO2 retention on mechanical ventilation despite high Pplat (>30 cm H20);
- Severe air leak syndromes;
- Need for intubation in a patient on the lung transplant list;
- Cardiac or respiratory collapse
ELSO Mortality Rule
ELSO Mortality Rule:
ECMO should be considered when the expected mortality rate surpasses 50%,
ECMO is indicated when it exceeds 80%.
ARDS severity and Expected mortality with P/F ratio >200-300?
>200-300
Mild ARDS
27%- expected mortality
ARDS severity and expected mortality with P/F ratio of >100-200?
P/F Ratio >100-200
Moderate ARDS
32% expected mortality
ARDS severity and predicted mortality with P/F Ratio of ≤100
Severe ARDS
45% predicted mortality.
Impact of CRRT on mortality
3.7 fold increase
