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Clerkship in CVS Tutor s Feedback on Homework Reporter Dr Tutor Dr Presentation Time 2020 03

Hi Kate Extracorporeal Membrane Oxygenation ECMO Critical Care IF 6 959 ECMO ECMO Configuration review

UpToDay 100 202003

4 Things you need to know about ECMO before you read this article

ECMO Structure ECMO draining cannula ECMO return cannula 6

ECMO Configurations in common ECMO Inflow draining ECMO outflow 8

VA VV V A SVC RA V VA VAECMO RA VAECMO LV

VV VVECMO Lung protective ventilation VAECMO VVECMO

11 The position of the draining limb affects patient s ABG

Reversed Differential Cyanosis in VAECMO SaO2 values are different in upper and lower body parts If the recovery of heart is Check ABG in upper limb earlier than lungs SaO2 in ABG Mixture of B and C Check ABG in lower limb SaO2 in ABG B dominantly

VA Reversed Differential Cyanosis VA reversed differential cyanosis reversed coarctation of aorta

VAECMO C B B C B 100 FiO2 1 0 C C B B C B C RA A A B C A B C RA B C

VAECMO A B B C B B C Starling law C Reversed differential cyanosis VAECMO C B cyanosis

Over Recirculation in VV Mode Recirculation fraction Rf Q1 Q5 Venovenous ECMO Q1 Q2 ECMO flow Q1 ECMO oxygenated blood recirculated Q2 ECMO oxygenated blood notrecirculated Q5 Q3 Mixed blood partially refreshed by ECMO Q4 Pulmonary oxygenated blood Arterial blood Q5 Blood entering ECMO draining tube

VV Recirculation VV Recirculation IVC SVC RA RV ECMO RV Q1 Q2 RV RA Q5 Q1 VVECMO recirculation fraction Rf Q1 Q5 Rf RV VVECMO

VV ECMO The distance of two tips affects the severity of recirculation 15 cm

Recirculation Rf RV ECMO pump RA RV VVECMO Rf VVECMO Rf Rf RV Q3 CXR 15

20 This paper says that

21 Factors affect the O2 carrying capacity of ECMO Oxygen delivery DecmoO2 in ml O2 min DecmoO2 Flow x Hb x 0 0134 x 100 Satpreox Flow ECMO pump flow L min Limited by the size of cannula Hb hemoglobin concentration g L Satpreox preoxygenator saturation Different SO2 in SVC and IVC

ECMO pump flow ECMO Poiseuille s law 100

Poiseuille s law 23 4 https zh wikipedia org wiki E6 B3 8A E8 82 83 E5 8F B6 E5 AE 9A E5 BE 8B

1 Rf VVECMO

Recirculation a b IVC RA b showed less recirculation Rf and maintain higher ECMO flow than RA IVC a in previous studies Configuration is recommended now 26

Rf a b VVECMO IVC ECMO SVC SVC ECMO IVC Rf SVC IVC ECMO SVC

The author s recent study found 28 RA IVC multistage cannula in SVC multistage cannula 25 Fr 38 cm tip side hole distance 10 cm conventional cannula 23Fr 25 cm Multistage Conventional Outcome RF 18 RF 38

SVC multistage cannula Rf

2 VA reversed differential cyanosis

Reversed Differential Cyanosis in VAECMO SaO2 values are different in upper and lower body parts Check ABG in upper limb SaO2 in ABG Mixture of B and C Check ABG in lower limb SaO2 in ABG B dominantly

VA Reversed Differential Cyanosis VAECMO Reversed Differential Cyanosis LV LV Multistage SVC IVC VAECMO Table 1 VAECMO

Solution 1 Reducing the Native Cardiac Output 33 Put the multistage cannula in SVC rather than in IVC More reduce the native cardiac output

Solution 2 Moving the arterial cannula to SCA 34 Shifting the outflow cannula from FA to SCA Disadvantage Technically more demanding Hyperperfusion of ipsilateral arm Surgical bleeding Cerebral emblosim

VAECMO SVC Femoral iliac artery VVA ECMO VA VV VV VA VV VA VV VV VA VVA ECMO VV

Solution 3 Using Hybrid mode V VA Mode Implant an extra outflow cannula into IJV Problem Difficult flow control Recirculation in VV subsystem VV flow dominant in VA hypotension 36

SVC multistage cannula Reversed Differential Cyanosis in VAECMO

3 20200312