Extracorporeal membrane oxygenation (ECMO) is an artificial life support measure that typically takes place in a hospital’s intensive care unit (ICU). It can be used to temporarily stabilize a patient, providing cardiovascular and/or respiratory support while a course of treatment is determined or while waiting for a heart or lung transplant. It’s a highly specialized treatment that has been refined over the past few decades and, as the technology continues to advance, pre-hospital and inter-hospital ECMO has become a possibility. Research continues apace on portable and wearable devices in order to refine their suitability for pre-hospital and interhospital contexts and, now, not only is ECMO no longer tethered to a hospital environment, it can also take place in the sky. Providing, that is, the requirements for this highly specialized, expensive and resource-intensive procedure are met.
All the gear and the right idea
A compact, portable device called Cardiohelp is one option for providing ECMO support in an aircraft setting, and a key benefit is its convenience. “Jet Rescue utilizes the Cardiohelp ECMO machine because of its portability,” Carlos Salinas, CEO, Jet Rescue, told AirMed&Rescue. “This device was designed specifically for transport; it is small and lightweight.”
Alexander Fuchs, Consultant Anesthesiologist for the Department of Anesthesiology and Pain Medicine at the University Hospital of Bern, also uses Cardiohelp. “The helicopters (Airbus H145s) can be additionally equipped with a custom-made fixation plate. If needed, a second fixation plate can be attached, and there is even the possibility of having a simultaneous running ‘Impella’ for unloading the left ventricle in patients with severe cardiogenic shock (ECMO + Impella = ‘ECMELLA’),” he said. “We normally work with the Cardiohelp System. Specialized perfusionists are picked up at the receiving hospital. They carry the Cardiohelp System, a backup oxygenator, and other materials for troubleshooting during transport.”
Some aircraft have been modified in order to carry ECMO equipment, as Manfred Helldoppler, Managing Director at Tyrol Air Ambulance, elucidated: “The G100 fleet was modified to make sure that the ECMO equipment can be properly fixed and stowed in the cabin, including the required mass and balance calculations. Which equipment is used for a flight is decided case by case, based on the requirements of the mission.”
Now, not only is ECMO no longer tethered to a hospital environment, it can also take place in the sky
Other aircraft are licensed as mobile intensive care units (MICUs) and require no additional equipment, as is the case for Med-Trans, which is part of the Global Medical Response family of companies: “Our partner hospitals send all necessary equipment, including dedicated cardiovascular perfusionists, for patients on ECMO,” said J Chad Curry, Flight Paramedic. “The ECMO teams accompany our standard air medical team consisting of our pilot, critical-care-trained nurse and flight paramedic.”
As is to be expected, the equipment required is by no means cheap. “Bespoke trolleys with integral ECMO consoles and motors and backup equipment cost around £100,000–£110,000,” said Jo-anne Fowles, Nurse Consultant for ECMO and Critical Care, Royal Papworth Hospital.
An additional cost, added Helldoppler, comes in the form of a variable surcharge that usual intensive care flights don’t have. “This is decided separately for each ECMO flight, depending on the length of the mission, the procedures expected and the equipment needed.”
Critical expertise for critical care
In terms of the expertise required, Fowles explained that several specialists are ‘essential’ to deliver the treatment:
• A medical doctor trained in intensive care or anesthesia with add-ons such as ECMO and transfer experience
• An ECMO specialist retrieval nurse with training assisting cannulating the patient for ECMO support
• A clinical perfusionist trained in ECMO.
Curry said that the requisite training includes a hemodynamics class. “This covers ECMO, intra-aortic balloon pumps (IABP), ventricular assist devices (VADs) and in-depth cardiopulmonary physiology.” He explained that it is the perfusionist who is responsible for managing their equipment: “The aircrew does not alter the device. At times, in consultation with the ECMO team, they will ask for changes to affect blood pressures and/or oxygenation, depending on how the patient is cannulated (venovenous or venoarterial).”
Salinas said that a consortium called the Extracorporeal Life Support Organization (ELSO) provides training, research, and support to ECMO providers.
“Managing an ECMO patient is a specialty in itself,” he said. “Our crew is trained by ELSO, and members include specialized physicians like cardiovascular surgeons, critical care physicians, anesthesiologists, and perfusionists.”
Of course, such a highly specialized procedure is not without its challenges, and these are intensified still further at the great heights of the air ambulance setting. “Any company offering ECMO flights must be aware that ECMO therapy is already a high-risk, ultima ratio procedure on ground level in the safe environment of a hospital,” said Helldoppler. “It is a procedure with an individual mix of technical and medical challenges. The associated risk for unforeseen complications is already high on ground and highly dynamic, and can result in a rapid change of the situation of the patient.”
Any company offering ECMO flights must be aware that ECMO therapy is already a high-risk, ultima ratio procedure on ground level in the safe environment of a hospital
As such, a patient’s suitability must be rigorously assessed in advance. “There is a need for robust ECMO service specifications, including patient criteria for suitability of ECMO support and a bespoke referral system for doctors to refer patients to specialist units for consideration of ECMO support,” said Fowles. Subsequently, strict processes are to be respected. “There are clear processes to ensure patient and team safety during transfer,” she said.
Curry said that a prominent challenge is safely loading and unloading the patient. “These patients typically are on anywhere from five to seven intravenous infusion pumps. They are often intubated and require ventilator support, plus the actual ECMO machine and the circuits attached to the patient,” he explained. “It becomes a skilled game of Tetris to not disturb the lifesaving support occurring while safely fitting and securing all items into the aircraft.”
Fuchs agreed that loading and unloading can prove challenging: “The ECMO must always be lower than the patient’s heart, and the cables are often too short.” He said that an additional challenge is that space is at a premium: “There is limited space in the helicopter for troubleshooting, especially when the patient has femoral vein cannulation, as it is hard to check the cannulas during the helicopter flight (all must be checked before take-off).”
Not always smooth flying
It becomes a skilled game of Tetris to not disturb the lifesaving support occurring while safely fitting and securing all items into the aircraft
As such, there are a plethora of important considerations, which Salinas divides into planning, anticipation and risk mitigation according to the different transport phases. “The mission is divided into four phases of transport: 1) patient selection, 2) pre-transport, 3) patient packaging and 4) transport. Each phase of the mission carries unique challenges,” he stated. “The riskiest phase is the transport phase. Having enough supplies, specialty medications and oxygen is paramount.” Salinas said that the most common complication encountered with ECMO cannulation is bleeding. “Awareness of the patient’s hemoglobin, platelets, coagulation profile and anticoagulation status will help guide decisions to mitigate bleeding risk,” he explained. “As there is no monitoring or testing of coagulopathy in the en route environment, it is critical for the team to assess and treat as necessary prior to transport and prioritize repeat testing upon arrival at the destination facility.”
The vibrations of the aircraft also create challenges. “Vibration from ground and/or air travel may worsen patient pain and discomfort,” said Salinas. “To mitigate these factors, additional care must be taken to ensure that the patient is appropriately padded, secured, and provided with adequate levels of analgesia and sedation.”
Fuchs pointed out that this can also impact readings of patient vitals: “During the flight, the patient’s vital parameters on the monitor can have artificial false values often caused by micro-vibrations.”
Another challenge, said Salinas, which is actually one of the biggest, is the logistical implications when flying internationally: “This includes landing permits, overflight permits, and oxygen refilling. During the Covid-19 pandemic, ECMO was one of the most important tools to help patients. The airspace restriction during the pandemic was also a major challenge.”
Whatever the setting, the stakes are high when it comes to ECMO, but there are particular challenges and considerations specifically associated with ECMO in the air, including the need for rigorous preparation and strict processes to adhere to. If an air medical patient is a candidate for ECMO support, this could represent a lifesaving measure and, although complex, ECMO in the air is feasible and safe with a highly specialized team with quick thinking skills and the required equipment.
“You need highly trained and experienced personnel for ECMO transfer,” said Fuchs. “They need to know what can happen, why and how; quickly detect errors; and immediately respond with appropriate troubleshooting. These transports are safe when performed by experienced teams. However, the patients undergoing ECMO are in a very critical condition, and they have the risk of adverse events at any time – also in the hospital. Adverse events during the transfer will happen; you need to be aware of this.
“Furthermore, improvisation skills are essential in pre-hospital emergency and critical care medicine,” he continued. “The more you plan and train, the less you need to improvise, but unfortunately, you can’t plan everything in medicine. You are treating a human being and not a predictable machine.”