On the 6th January 2023, the JJJCTS Clinical Academic Program hosted a Grand Round at Netcare St Augustine’s Hospital, Durban. The aim was to discuss the practice’s new VV ECMO patient’s case and to share knowledge and facilitate mutual learning. It was attended by various members of the multi disciplinary team including nursing (ICU & theatre), physicians, surgeons, physiotherapists.
Dr S explained that Mr K (our patient) was admitted on the 12/22. He is 36 years of age, known immune compromised. He was treated for PCP pneumonia and after 7 days of ventilation managed extubation. However, he had an acute hemoptysis and was reintubated. At this point he was referred to Dr Pillay for ECMO. As far as patient selection goes, the patient was younger than 65 years, he had single organ failure (respiratory) and a reversible cause. He was severely hypercapnic and hypoxic with a “white out” chest x-ray which prompted a quick ECMO insertion procedure, and a group decision was made to cannulate at the bedside due to the risk of transport at SpO2’s = in the 50’s at times. The ICU staff were very quick and amenable to get everything ready and a great theatre team coordinated the emergency cannulation. Despite remaining fairly stable in terms of blood pressure with a severe respiratory acidosis, a low dose of adrenaline was started.
An Avalon catheter was inserted into the right internal jugular and positioning was confirmed using TEE (Transesophageal echocardiography) by Dr O(anesthetist). As shown in this diagram below, the Avalon catheter is dual lumen, it enters the right atrium through the superior vena cava and continues beyond to the inferior vena cava with the tip around the 10th vertebral body. Venous blood is drained from both the IVC and SVC from little holes in the top and bottom of the cannula, it is then oxygenated by the ECMO oxygenator and oxygenated blood is returned to the right atrium through a different lumen. This returning blood flow is directed towards the tricuspid valve.
The use of the Avalon dual lumen cannula’s advantages were discussed by RN. Rene Gomes and the attendees
-less chance of infection (as compared to two separate cannulas and sites, one of which would be femoral)
-less chance of accidental dislodgement (as there is only “one cannula”)
-less wound care and nursing care as only one site
-patient can be mobilized at a later stage, can even walk around the unit without femoral hindrance!
-VAP principles of >30 degree head of bed elevation are potentially easier to facilitate
The difference between VV and VA ECMO was discussed
The two letters representing access and return cannulation sites effectively created the two different modalities.
SO in VV (as with this case) deoxygenated blood is drained from a vein and oxygenated blood returned to a vein. (this is respiratory support)
As opposed to VA where deoxygenated blood is drained from a vein and oxygenated blood returned to an artery (which is systemic or cardiac support)
Each mode has different indications.
A few principles of ECMO care were shared by RN Rene Gomes and Dr Fulton
- Ventilation
As soon as the patient is successfully cannulated it is imperative that ventilation strategy is changed to ultra lung protective. “You can’t put lungs in plaster of Paris if they are broken, but you can rest them on ECMO” ECMO is the ultimate pause button to give you time as the medical practitioner to reverse the cause whilst gaining a more stable patient in the interim.
Suggested Ventilation strategy for this patient
Is
APRV mode
Fi02 <60% or less than 40% even better
A P high of 25
P low of 3-5
T high 4-5 secs
T low 0.4-0.7 secs
Don’t chase tidal volumes in this initial phase, the ECMO is going to oxygenate and take care of gaseous exchange. Resting the lungs but retaining lung recruitment is the mandate initially.
If you have a hypercapnic patient with pH affected it should be managed with the sweep gas. It is very effective so increase by 1-2l/min at a time. Monitor ABG.
If your patient is hypoxic the idea is not to touch the ventilation setting if possible and rather increase the flows on the ECMO so a larger volume of blood is oxygenated more quickly.
*a note of hypoxia of VV ECMO patients generally a saturation of 88% and above is accepted and paO2 >55mmHg.
Monitor Lactate as a measure for adequate oxygenation.
Flows are generally started at around 60% of patient Cardiac output. (50-80ml/kg/min)
- Sedation
Adequate sedation is imperative to ensure proper access and decrease oxygen consumption. Pharmacodynamic challenges are common with these critically ill patients. Consider Dormicum, Morphine, Propofol and the addition of Ketamine infusions. Intermittent paralysis is also often required.
- IPC
Strict Contact isolation practice is critical in addition to any other measures indicated depending on cultures etc. Acquiring a CLABSI is absolutely devastating in these patients. Sepsis being the biggest enemy in this setting and will worsen your patient’s prognosis significantly!
- How to manage the Rock ‘n Roll!
Access insufficiency is often the most common “trouble shoot” managed on the floor. A “kicking”/ “rock n roll” motion of the circuit is noted with fluctuating flows. This is not the time to ignore and go to tea! Get a buddy to assist and have a quick scan of obvious practical things e.g. Kinking of the circuit or anything else that might be hampering flows. Position of head and neck of patient etc. If all is in order, reduce the speed until a regular flow is maintained this is often below the patients’ requirements so expect a little instability. The reason for this is usually a dry patient, that is intravascularly dry. A fluid bolus is usually indicated, administer 250ml of colloid or blood if indicated at a fast rate and slowly the speed can be increased to where the patient was initially. This noticeable torque pulling motion called dancing or kicking can physically damage the access site causing hematoma or bleeding to the vessel so it must be managed timeously. Also restoring a constant stable flow is of utmost importance. Going back and forth with the speed whilst the fluid is being administered is a skill that develops with some practice. J
Best tip: don’t let your patient become fluid depleted
-transduce your CVP use the trend as a guide for fluid status together with the whole clinical picture. Monitor intake and output strictly with accumulative totals hourly so you can notice abnormalities before they become a problem. Discuss fluid status on the rounds as a team to prevent imbalance.
- Unique to VV ECMO- how to monitor for recirculation.
Recirculation is possible only in VV ECMO as oxygenated blood is returned to the same venous system. If already oxygenated blood is then drained to the ECMO machine instead of crossing the tricuspid valve into the right ventricle it once again will enter the drainage circuit and decreases the efficiency of the ECMO circuit. This results in dangerously low levels of oxygen delivery.
Look out for the colour of blood comparison in the two circuits should darker red in drainage circuit and brighter red blood in return. The more they look alike the more recirculation!
(This is correct coloration of the circuit.)
SV02 will increase unexplainably
Spo2 decrease.
Pre-Membrane blood gas will be high in pa02 levels
Tip: Often one of the causes could be cannula migration (see dual lumen Avalon info above) compare chest x-ray tip of cannula from before with optimal flow position etc. to current.
We had a little time for Q&As…
A question from the physiotherapist was about treating the patient.
A: VV ECMO patients definitely need physiotherapy. (Respiratory disease and critical illness weakness) Treat the patient, check with the MDT if the patient has any active bleeding, as with this patient, then chest physio would be contraindicated. But passives would be necessary for example. Keep an eye on the hemodynamic monitoring and the ECMO flows and cease if become abnormal. Always remember the integrity of the ventilator circuit to retain recruitment. DO not skip physio!
Q: Why is it even necessary to ventilate at all, why not extubate if the ECMO is doing all the work?
A: They can be extubated if the patient is awake and co-operative, however, in the acute phase (which was in the case of Mr K) the airway needs to be protected as he is sedated, and due to his lung disease, recruitment would be beneficial.
*Everyone was encouraged to download the free Alfred ECMO app. The Alfred is a hospital in Melbourne, Australia that does high volume ECMO and lung transplant center, and their evidence based protocols are excellent and what the JJ&J practice’s will be modelled on!
This concluded the grand round. We thank everyone for their participation and interest! See you at the next one!
*Grand rounds are hosted on the first Friday of every month, venue might change based on patient selection at the time, join our whatsapp group to stay up to date on future events!
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