ECMO

Inclusion criteria:

>34/40 weeks gestation age, reversible cardiac, pulmonary, or cardiopulmonary failure, mechanical ventilation <14 days.

Exclusion criteria:

Major intracranial haemorrhage, lethal malformation, severe neurological injury, untreatable cardiac or pulmonary malformation.

Clinical indications:

• Failure to wean off cardiopulmonary bypass, oxygenation index >40 on two or more ABG despite maximum therapy [OI = (MAP * FiO2 * 100) / PaO2]
• Intractable metabolic acidosis
• Progressive intractable pulmonary or cardiac failure

Flow rates on full VA ECMO support:

• In patients <10 kg aim for 100-150 ml/kg/min
• In patients >10 kg aim for CI 2.4 L/min/m2
• Consider higher flow rates in septic patients, univentricular hearts with open systemic-pulmonary shunts and extracardiac shunts

Flow rates on full VV ECMO support:

• In patients <10 kg aim for 70-140 ml/kg/min
• In patients >10 kg aim for CI 1.8 L/min/m2
• Consider higher flow rates in septic patients, univentricular hearts (cave: inappropriate high SmvO2 might indicate recirculation)

Cannulation:

• ABG, FBE, coags, UEC, Ca⁺⁺, Mg⁺⁺, LFT, SBR, ABG, obtain blood culture/urine for M, C and S/ETT aspirate for M, S and S, optimise coagulation if possible, consider blood sample storage for genetic analysis
• Cephazolin (50 mg/kg IV) 30-60 min prior to procedure
• CXR, ECHO, cranial ultrasound
• Arterial line placed and secured, central line placed (not RIJ or R subclavian) and secured
• Chest drain placed, if required and secured
• Neck cannulation: position patient head outwards in bed space and neck overextended with roll under shoulders
• Transthoracic cannulation: supine position with roll under back
• 2 x venous line extensions
• Fentanyl 5 mcg/kg IV bolus, vecuronium 0.1 mg/kg IV, consider fluid resuscitation/enhance inotropic support if needed
• Surgical preparation
• Give heparin on surgical request (50-100 U/kg if appropriate for patient situation), surgical cannulation & connection of tubing (<15 kg → ¼”, >15 kg → 3/8″ circuit)
• Set FiO2 100% and sweep gas flow, turn RPM to 1000-1200, unclamp venous line, unclamp arterial line, increase slowly RPM to desired flow
• Reduce inotropic/vasoconstrictor accordingly, observe ABP/inlet pressure/outlet pressure/CVP
• Recheck ACT every 30 mins, commence heparin infusion 20 U/kg/hr once ACT <250
• Once on full flow, change to ventilation rest settings (PEEP 10, PS + 10, Vt 6 ml/kg, RR 10, FiO2 30-40% in VA ECMO FiO2 60% in VV ECMO)
• Secure cannula position, commence analgesia & sedation & paralysis, CXR, ECHO, fluid restriction to 60%

Anti-coagulation:

Keep ATIII level >80%: No. IU = (desired – actual level) X Wt, Heparin [Patients <10 kg: 5 KU/50 ml 0.9% NaCl; patients >10 kg: 25 KU/50 ml 0.9% NaCl]

Commence heparin on 20 U/kg/hr, adjust in regards to ACT.

Weaning in VA ECMO:

• Ensure volume status is adequate
• Ventilate patient with acceptable settings (as blood flow through lungs increased)
• Decrease pump flows by 10 ml/min every 60 min down to a minimum of 40 ml/kg or 250 ml/min total flow through oxygenator
• ABG 15 mins post each wean of flow
• ECHO at lower flows, [do NOT turn sweep gas off – all flow going through circuit bypasses lungs. Minimum sweep gas setting is 200 ml/min], bridge or decannulate

Weaning in VV ECMO:

• Commence full ventilation
  Sweep gas FiO2 at 0.21 for approx 10 minutes to flush O2 from oxygenator
• Turn sweep gas to minimum setting of 200 ml/min, run ACT’s 200-220 whilst pt still on ECMO circuit
• Observe patient saturations, ABG after 30 mins (oxygenator continues to oxygenate for approx 20 mins after sweep gas flow is ceased)
• Organise for decannulation

References:

[1] Cardiol Young, 2007; Sep;17 Suppl 2:104-15: Cooper et al: Cardiac extracorporeal life support: state of the art in 2007

[2]

[3] Lancet, 1996 Jul 13; 348(9020):75-82: UK collaborative randomised trial of neonatal extracorporeal membrane oxygenation. UK Collaborative ECMO Trail Group

[4] Cochrane Database Syst Rev. 2008 Jul 16;(3):CD001340: Mugford et al: Extracorporeal membrane oxygenation for severe respiratory failure in newborn infants.

[5] Lancet. 2009 Oct 17;374(9698):1351-63: Peek et al: Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial.

[6] Intensive Care Med (2012) 38:210-220: MacLaren et al: Contemporary extracorporeal membrane oxygenation for adult respiratory failure: life support in the new era

[7] Artif Organs. 2013 Jan;37(1):21-8. Kotani et al: Evolution of technology, establishment of program, and clinical outcomes in pediatric extracorporeal membrane oxygenation: the “sickkids” experience.

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