外科の高侵襲な手術後の周術期管理において、問題となる合併症の一つに誤嚥性肺炎があります。特に大量の消化管内容液を誤嚥した場合の、化学性肺炎、ARDSが誤嚥直後から大きな問題になります。酸素化が不十分な場合は気管挿管した上で人工呼吸器管理が必要となります。FiO2100％でも、PaO2が50~70台で酸素化が不十分な場合は、ECMOの適応になる状態です。私のように一般外科あがりで、集中治療専属研修の期間が少ないと、どこでECMOに踏み切ればいいのか、躊躇してしまうこともあると思います。当施設で採用しているECMO protocolを下記に転載しました。なかなか馴染みがないとECMOを頭の片隅で考えても、コンサルトを躊躇してしまうこともあるかと思います。そんな時の意思決定の一助になればと思います。
Is the patient suitable for ECMO?
Veno-Arterial ECMO (VA)
- Cardiogenic shocks with end-organ hypoperfusion
- CI <2.2L/min/m2 or SvO2 < 60% on two inotropes
- High biventricular filling pressures (PCS > 20, CVP > 15)
- Rising lactate
- Worsening metabolic acidosis
- Hypotension with significant vasopressor requirement (two or more of the following):
- Norepinephrine ≥ 10 mcg/min
- Vasopressin ≥ 0.04 units/min
- Phenylephrine ≥ 100 mcg/min
- Epinephrine ≥ 1 mcg/min
- Unstable arrhythmias
Common Indications for VA ECMO
- acute coronary syndrome
- cardiac arrhythmic storm refractory to other measures
- sepsis with profound cardiac depression
- drug overdose/toxicity with profound cardiac depression
- myocarditis
- pulmonary embolism
- isolated cardiac trauma
- acute anaphylaxis
- Post-cardiotomy with inability to wean from bypass
- Periprocedural support for high-risk percutaneous cardiac interventions
Veno-Venous ECMO (Lung Support) (VV)
- Acute hypoxic or hypercarbic respiratory failure
- O2 Sat ≤ 88% on FiO2 100% (PaO2/FIO2 ratio <100) with PEEP ≥ 15 with plateau pressure ≥ 30 cmH2O
- Failure to improve Pao2/FIO2 ratio with center-specific interventions including but not limited to:
- low tidal volume 6ml/kg strategy
- proning
- paralysis
- inhaled nitric oxide or epoprostenol
- Respiratory acidosis with pH < 7.20
- Normal RV/LV function
- Vasopressor/inotrope requirements to be discussed with ECMO physician
Common Indications for VV ECMO
- severe bacterial or viral pneumonia
- aspiration syndromes
- Status asthmaticus
- airway obstruction
- pulmonary contusion
- smoke inhalation
ABSOLUTE CONTRAINDICATIONS (to be screened by ECMO MD at referral)
- Acute Intracranial hemorrhage or massive stroke
- Severe non-reversible brain injury
- CPR>60 minutes in-house and/or 30 minutes out of hospital
- Severe Aortic Insufficiency
- Acute Aortic Dissection
- End Stage Liver Disease
- Contraindication to anticoagulation
- Terminal malignancy
RELATIVE CONTRAINDICATIONS
- Age: no specific age contraindication but consider increasing risk with increasing age
- Mechanical ventilation > 7 days
- Suicide attempt
- Multi-organ failure
- Lack of social support or lack of healthcare proxy
- BMI>40
ECMO Consult/Referral
Referral Checklist
- Weight, height, BSA
- Vital signs, PA line hemodynamics
- CPR duration, if performed
- Medications (inotropes/pressors, IABP)
- Labs (CBC, CMP, coags, lactate, SvO2, ABG
- 12-lead ECG
- Cardiac catheterization
- Echocardiography
- Last neurologic examination
- Mechanical ventilation and recent CXR
- Vascular examination/history
- If already on ECMO, cannulation site and size of cannulas
