Veno-venous extracorporeal membrane oxygenation in severe acute respiratory failure Flashcards
1
Q
Components of a VV ECMO machine
A
- Venous drainage cannula
- Pump
- Heat and gas exchange unit
- Venous return cannula
2
Q
How is % blood oxygenation determined when a patient is on VV ECMO
A
- % of blood bypassing ECMO circuit- determined by patient’s CO will be partially oxygenated by diseased lungs
- % of blood travelling through the ECMO circuit- determined by size of cannula and speed of pump (generally 3.5-6L/min)
3
Q
How is CO2 clearance controlled in VV ECMO
A
Setting the sweep gas flow rate, the higher the flow rate the larger the CO2 gradient the more CO2 will diffuse out. Normally 1-10L/min
4
Q
Trials into the efficacy of ECMO in ARDS
A
- CESAR
- EOLIA
5
Q
Indications for adult VV-ECMO
A
- Hypoxiaemia resp failure (PaO2/ FiO2 ratio <10.7kPa) despite optimal medical management: proning, lung protective ventilation
- Hypercapnic resp failure (pH<7.25) despite optimal conventional mechanical ventilation
- Ventilatory support as a bridge to lung transplantation or graft dysfunction after lung transplantation
6
Q
Poor prognostic factors when considering initiating VV-ECMO
A
- Age: no set cut off but evidence suggests >65yrs = poor outcome
- Weight: Obesity paradox, some survival benefits if BMI 28-35 but above this, poor outcome
- Immunosuppression: esp high-dose steroids
- Ventilatory days before ECMO >7 days
- Cause of resp failure: extrapulmonary (pancreatitis, non-pulm infections), assoc severe trauma
7
Q
Complications of initiating VV-ECMO
A
From Cannulation
- PTX
- Bleeding
- Arrhythmias
- Tricuspid valve injury
- Cardiac perforation and tamponade
- Venous air embolism
From initiating ECMO
- SIRS response to circuit
- Cardiac arrest
8
Q
Absolute contraindications to VV -ECMO
A
- Irreversible diagnosis without a plan for decannulation from ECMO
- Cardiac arrest with downtime >15 mins or evidence of severe neurological injury
- Established multi-organ failure
