1.

ECMO
#1 ECMO indication
When patient’s mortality is 50%, the doctor would consider ecmo treatment / and when the mortality increases up to 70%,
the doctor should start ecmo immediately. However, the survival rate of ecmo treatment / is only 35%.
This is because ECMO is used for only high mortality cases such as trauma, ARDS, severe cases of Covid-19 and et cetera (ect).
Therefore, ECMO is the most advanced medical treatment and if ecmo is not enough to save the patient’s life, there is no
other options left.

#2 Modes of ECMO
There are many different types of ECMO such as VV, VA, VAV, VVV, VVA but the main configuration of ECMO are VV aka
Veno-venous and VA aka veno-arterial. And the others VAV, VVV, VVA which we call them hybrid types.

2. VV, VA mode

First, VV ECMO gives time to patient’s lung to rest and recover while ECMO replaces the main function of lung which is
gas exchange that oxygenation and removing carbon dioxide.

Second, VA ECMO replaces the functions of heart and lung together which are cardiac pumping and blood circulation in
body and gas exchange so that heart and lung can rest and recover.
 3. Drain, outflow & Return, inflow

#3 Drain, inflow / Return, outflow

Mostly femoral vein and jugular vein are main and most favored site for blood drainage and return. However, there is also
two-lumen cannular. In this case, using Y-type cannular on jugular site for both blood drainage and return for VV mode.
This ECMO type is mostly used to support for organ transplantation case.

4. Cannula

#4 Cannula Type
The end of Venous cannular is long and has many small holes because vein has low blood pressure. In contrast, due to
artery has a higher blood pressure, artery cannular is short and has small number of holes on tip of cannular so that blood
of artery cannular go through into patient’s body against arterial blood pressure of patient’s own
 5. Component of ecmo (pump, flow, fio2, warmer, membrane, oxygenator)

#5 Component of ECMO
In general, ecmo is consist of pump, membrane, o2 blender, heat exchanger, drainage cannular and return cannular. To be
more specific, RPM of pump is different for each types of ECMO and its usually around 3600 rpm for VV mode and 5000
rpm for VA mode

#6 Difference RPM between VV mode and VA mode

The main reason of rpm difference between VV mode and VA mode is blood from ECMO has to go against different blood
pressure of vein and artery. So during VA mode, even though RPM is set as 5000, the LPM (blood flow) will be lower than
rpm, it’s usually around 4.0 or 3.5 and this is different from every patients depends on patient’s body weight and vascular
condition. (For example, if a patient has diabetes and hypertension, this will block ECMO’s blood return)

#7 Effects of VV mode
To be more specific, ECMO drains patient’s blood from femoral vein of inferior veno cava or from jugular vein of superior
veno cava which veins go into right artrium. Then through membrane of ECMO, the vein blood go through gas exchange
or oxygenation. After oxygenation, the blood become full of oxygen like arterial blood and it return to jugular vein or
femoral vein. So this mechanism replaces of pulmonary circulation. then the patient’s lung rest and recover by itself.

#9 VVV mode ecmo

In addition, while its VVV mode, ecmo uses two cannulars to drain blood from patients body and it helps to drain more
blood than vv mode with the same rpm. For example, when VVV mode has RPM 3700, then LPM (FLOW) would be 5.20
instead when VV mode with RPM 3700 can makes 3.2 LPM normally.
Usually VVV mode is used first when ecmo patient experience recirculation syndrome seconds doctors want to raise
LPM(flow) for patients with avoiding recirculation syndrome. For example, when VV mode patient rpm is 3600 and lpm,
flow is around 3.6 and 4.0, but doctor want raise ecmo flow and worry about recirculation syndrome then the doctor
probably consider VVV mode to use devided pressure on drain cannular avoiding recirculation.
 6. Blender, Flow meter

#10 Blender and flow meter

After the patients blood is drainged, it meets O2-CO2 exchange in membrane. During this gas exchange in membrane of
ecmo, the Blender functions as controller of FiO2, which ranges from 0.21-1.0 (the same oxygen control mechanism as
ventilator Fio2 for oxygenation). The flow meters controls the gas flow rate, speed of the gas, range from 0-10L (it must set
at least 0.1L above 0). Flow meter usually controls gas flow rate for CO2 level. In conclusion, Blender controls oxygen
concentration for Patients PO2 level and Flow meter controls its PCO2 level.
For example, when patients po2 is too low, raise fio2 in bledner for better oxygenation. when patients pco2 is too high,
increase the level of flow meter for more gas exchange.
 7. Blood return

#11 Blood return

After blood oxygenation in membrane of ecmo, the oxygenated blood pass through blood warmer device to match blood
temperture to patients body temperture.
 B. VV MODE
So far, this has been an simple explanation about principle of ECMO. From now on, im going to point out critical side
effects of ecmo that nurses need to continuously monitor and follow up nursing intervention.

#8 Common side effects of ECMO (Any types of ECMO, VA, VV, VAV, VVV) , bleeding, dislodge
While VV_ecmo treatment, there are several things to take care of. One, during ecmo treatment, use of continous of heparin
is inevitable which means patients might have to deal with bleeding side effects. So the nurse should assess gum bleeding,
bleeding on pucture site and cannular site. In addtition, regualr aPTT and INR test are necessary to check patient
coagulation ability. In the other hand, nurses also should be careful of management of cannulars patency. When doing
postion change, there is possiblity of dilodge and blocking of cannular. So please, pay attention not only patients position
for skin care but also cannualrs patency.

9. Recirculation

#12 Recirculation
During VV mode treatment, patient may experience Recirculation syndrome. When blood from ecmo return to Right atrium
passing by through superior vena cava for pulmonary circulation then it is supposed to go to whole body circulation too.
However, ECMO drainage blood through inferior vena cava right below of superior vena cava, it makes the oxygenated
blood from ecmo can not go to right atrium but is drainaged again to ECMO. This is what we call recirculation. When
patient experiecne Recirculation syndrome, ecmo flow will be checked lower than usual and nurse can observe different
colors are mixed in drainage cannular with bright color of oxygenated blood which is supposed to go to right atrium, not
to drainage cannula and dark color of vein blood.

To solve recirculation syndrome, the doctor probably lower ecmo rpm to reduce the negative pressure on drainage cannular.
For example, when ecmo rpm is 3600 and patient experience recirculation syndorome, doctor would lower rpm to 3550 or
3500 but its literally depends on patients condition. On the other way, doctor might consider VVV mode ecmo without
lowering ecmo rpm then ecmo can reduce negative pressure by deviding ecmo drainge pressure into two different drainage
cannulas. In this case, patient may maintain the same flow rate as before.
10.

To solve recirculation syndrome, the doctor probably lower ecmo rpm to reduce the negative pressure on drainage cannular.
For example, when ecmo rpm is 3600 and patient experience recirculation syndorome, doctor would lower rpm to 3550 or
3500 but its literally depends on patients condition. On the other way, doctor might consider VVV mode ecmo without
lowering ecmo rpm then ecmo can reduce negative pressure by deviding ecmo drainge pressure into two different drainage
cannulas. In this case, patient may maintain the same flow rate as before.
 13. Fluctuation, Kicking

#13 Fluctuation, Kicking

Cannula fluctuation is literally drain or return cannula is shaking slightly. It might cause first dislodge of cannula from
inserted site, second bleeding from inserted site, third interuption of circulation.
During ecmo treatment, po2 and spo2 are depends on patients blood volume and circulation not really related to
respiratory system much. For example, if patient received too much iv fluid then I/O becomes positive 2000, it could lead
pulmonary edema. then doctor probably use Lasix 40mg 1@ IVs, but unfortunately, the lasix is too much effective for the
patient and I/O become negative - 4000. This is fluid deficit or volume deficit of patients and it causes low spo2 and low
po2 because blood volume is respiration cavacity during ecmo treatment.

To solve fluctuation or kicking issues, we need to give the patient more volume. Mostly we can find plasma solution that
mixed with albumin, that connected with ECMO cannula by three-way. We give 200-300cc of that plasma solution to patient
and this must be done by doctors order because too much of plasma loading may cause cardiac megaly or pulmonary
edema.

In the other hand, there is certain odd case of fluctation. When CS doctor ties cannular, attatches to venous wall too
closely, fluctuation would happen countinusly. In addition, plasma solution loading would not solve this problem and it can
be solved by repositioning cannula by surgern.

To conclude, during VV ecmo treatment, Blood volume and Blood pressure are key factor that have critical effect for ecmo
circulation which end up with good spo2 and po2 results. Again, using too much lasix cause deficit of body volume and
low ecmo flow circulation. It will lead decrease of spo2 and po2. Furthermore, Patients high blood pressure is negative
factor for ecmo circulation because ecmo return blood has to go against patients blood pressure.
 17. VAV

#14 VAV Mode

Mostly, after long term of ecmo treatment, blood of ecmo outflow and cardiac-self flow go to RA atrium together, and it
creates an another cardiac issue. Commonly, nurse can observe passing by a-fibrilation or pvc. However, to confrim patients
cardiac condition, you need to receive professional consult advise from CS or IC department through TEE, 2D-Echo. After
that, if patient with VV mode of ecmo treatment has extra problem with his heart, doctor probably change ecmo mode
from VV mode to VAV mode. This is to treat lung and heart together at the same time.
The average recommended period of ecmo cannula use is 2 weeks. So every 2 weeks, CS team must change ecmo
cannulas.

이건 VA mode를 설명하고, 뒤에 추가로 한번 더 설명해드릴께요.

18. 에크모 평균 사용권장은 2주이고, 보통 2주 지나면 cannula circuit을 change 합니다. 하지만 최대 3개월까지 에
크모 사용하고 생존한 국내 사례도 있습니다.

19. 국내 에크모 환자 평균 생존률은 35%입니다. 에크모 사용권장 상태는 환자 mortality(사망률) 50%면 에크모 사
용 고려해야 하는 상황이고, mortality(사망률)80%면 지금,당장,바로 에크모 박아야하는 상태입니다. 대부분 local 종
합병원은 어렵고, 도시별 대학병원에서 가능합니다.
 C. VA mode

#15 VA mode
VA mode is stand for Venous-artery mode of ecmo. Ecmo drainages blood from vein of the patient and return the blood
to artery of patients. This treatment gives heart much time for rest and ecmo actually replaces most of heart function itself
so that heart can take rest and recover.
 21. North & South Syndrome

#16 North&South Syndrome

There are several side effects of VA ecmo that require nurses close observation and monitoring. As I mentioned above
bleeding, dislodge cannular. fluctuation and kicking are common side effects.

North & South syndrome is that the return blood from ecmo is supposed to go to head and hand for clear circulation.
However, because of pefusion of patients heart, the return blood bumps to cardiac out from Left ventricular and the ecmos
return blood can not go to upper body clearly. This phenomenon is called North&South syndrome or mixing cloud.

To monitor mixing cloud, doctor always insert a-line on right radial wrist so that we can confirm if ecmos return blood
which properly circulate to upper body by ABGA lab test on a-line of right radial.

#17 Treatment for north & south syndrome

The reason of north and south syndrome is that the systemic circulation of heart, to reduce the pressure of systemic
circulation of heart, Doctor can change ecmos mode from VA mode to VVA mode. With VVA mode of ecmo, ecmo can
drainge more blood from heart, which means this reduces the amount of systemic circulation of heart so that ecmos return
blood can go to upper body easily.
 23. Ischemia

#18 Ischemia
Another side effect of VA ecmo is Ischemia becasue of low circulation below femoral artery from artery cannula inserted
(ecmos return blood heads to upper body so that lower body especially the leg which ecmo cannula inserted is hard to
receive ecmos return blood).
 To prevent ischemia, small bridge cannula which called distal perfusion inserted to down direction. However, because this
little distal perfusion also bumps to blood pressure of legs, distal perfusion often filled with blood clot. When distal
perfusion makes blood clot, distal perfusion color changes from birght red to dark red. When you find distal perfusion is
filled with blood clot, you have to drainge blood clot with syringe through three way of distal perfusion thne clean blood
from ecmo will fill up in distal perfusion. Do not push the syringe, if you do that the clot will go into the body and
patient will have serious complication.
 25. D-Shape

#19 D-Shape
when a patient has a long term of VV ecmo treatment, eventually the patient would have heart issue at the end. Then
doctor prabably change ecmo mode from VV mode to VA mode to treat lung and heart both. Furthermore, if a patient has
a long-term of VA ecmo, patients also will have lung issues at the end. Like VV ecmo, doctor also apply VAV mode ecmo
to treat long and heart both.

During VAV treatment, patient would have D-shape, the side effects of VAV treatment. Because patients heart would have
receive blood from 3 different direction, one from ecmos artery return at right in front of left ventricular, another one is
from venous return right in front of Right Atrium, the other is patient self systemic circulation. Long term of ecmo
treatment even though it gives time to recover for heart and lung, unfortunately function of heart becomes weak and the
septum of heart and it leads flatted interventricular spetum, which is called Septum configuration. (D-shape must be
confirmed by Cardiac sonography by CS physician) . Furthermore, this D-shape decreases the function of Left ventricular and
decline EF, ejection function. It makes blood stay in ventricle and also causes blood clot in heart. Then there are high level
of possibility for cardiac infarction and cardiac arrest. (Nurses might observe a-fibrilation and PVC on patients EKG)

Because of D-shape, the amount of preload is bigger than afterload and Left ventricular is smaller than before. Eventually,
blood would be stuck in Left ventricle.
 26. Septal puncture

#20 Benting
The final procedure for this matter, D-shape is benting. When D-shape is made and the blood is stuck in ventricle, doctors
would do puncture on septum so that blood in left ventricle would not be stuck in left ventricle and it let blood comes
and goes between right ventricle and left ventricle. However, Ive never seen any survivors after benting procedure because
the most patients were very ternimal stages of their condition I believe.

Ecmo requires medical professionals understand biological connection link between ecmo, patient, blood circulation, BP, Urine
output, recirculation, fluctuation, distal perfusion for proper management of ecmo treatment.
 27. Central ECMO

As you can see in the photo, Central ECMO drains blood from left ventricle and right atrium both at the same
time and give back the oxygenated blood to aorta so that heart can be completely empty like no blood in
heart and heart no need work for blood circulation and fully focus on its own resting.

It looks like 2 cannular system, but due to using y-connector, it actually 3 cannular system like VAV which
make heart and lungs both rest.

Most patients with central ecmo are very severe cases. Usually when heart operation went wrong way in or,
then the patient comes to ICU with central ecmo and the doctor would be very sensitive and aggressive.