Interhospital Aircraft/Ground Extracorporeal Membrane Oxygenation Transportation by a Mobile Extracorporeal Membrane Oxygenation Team: First Turkish Pediatric Case Series

Abstract

Objective:

Extracorporeal membrane oxygenation is a life-saving treatment for patients with circulatory and respiratory failure refractory to standard therapy. However, safe and timely patient transport to the referral extracorporeal membrane oxygenation center is critical for better patient outcomes in patients with acute cardiogenic shock. This study aimed to describe children’s features who were transferred to our center under extracorporeal membrane oxygenation by aircraft/ground vehicle and demonstrated the importance of extracorporeal cardiopulmonary resuscitation for transported children.

Materials and Methods:

We report the first Turkish pediatric case series of patients with acute cardiogenic shock transported by aircraft and ground ambulances on extracorporeal membrane oxygenation support to a referral extracorporeal membrane oxygenation center between January 2016 and January 2021.

Results:

Overall, 6 patients on venoarterial extracorporeal membrane oxygenation support were transported by aircraft and ground vehicles to our pediatric intensive care unit. Transport was achieved by fixed-wing aircraft in 5 patients and commercial aircraft in 1. Our mobile extracorporeal membrane oxygenation team cannulated 3 patients, and 3 patients were cannulated by the team at the hospital they applied to. The median age was 112 (range: 14-204) months and the median weight was 28.6 kg (range: 8.6-57.2 kg). The etiology of acute cardiogenic shock was fulminant myocarditis in 4 patients, dilated cardiomyopathy in 1, and transposition of great arteries and atrial flutter in 1. The median distance of travel for the patients to our hospital was 618 (407-955) km. No adverse events were detected during aircraft or ground vehicle transport.

Conclusion:

Mobile pediatric extracorporeal membrane oxygenation transport teams may provide safe aircraft and ground vehicle transportation in high-risk patients with acute cardiogenic shock bridging to survival or long-term circulatory support.

What is already known on this topic?

• Extracorporeal membrane oxygenation (ECMO) is a life-saving procedure for patients with severe reversible pulmonary or heart failure or who need a bridge for transplantation.

• Conventional transports to an ECMO center can be dangerous and fatalities have been identified. To initiate ECMO, the fully equipped mobile team travels to the hospital where the patient is being followed.

• Regional ECMO centers should be established for patients in need of ECMO, and transport protocols related to the transport process should be established.

What this study adds on this topic?

• Extracorporeal membrane oxygenation transport needs an experienced mobile ECMO team and appropriate logistics.

• Even though there are limitations, ECMO aircraft transport could be achieved without adverse events.

• Extracorporeal membrane oxygenation should be established in critical patients if needed, and patients should be transported to appropriate medical centers with mobile ECMO teams.

Introduction

Extracorporeal membrane oxygenation (ECMO) is a life-saving therapy for patients with circulatory and respiratory failure aiming to bridge long-term solutions. Most information on ECMO use comes from the Extracorporeal Life Support Organization (ELSO) international registry. According to the last ELSO ECLS international summary report, in July 2020, more than 10 500 patients with respiratory failure received ECMO support, and more than 12 800 patients with cardiac failure received ECMO. Extracorporeal membrane oxygenation is used to support extracorporeal cardiopulmonary resuscitation (ECPR) in nearly 5086 pediatric patients as reported in the ELSO ECLS international summary report until 2020.¹ Patients who need ECMO must be transported to a suitable medical facility if the patient in a center lacks ECMO service. The annual ECMO success of an ECMO center is proportional to the number of ECMO performed per year.² It is risky to transport critical patients who need ECMO because they are usually hemodynamically unstable. Extracorporeal membrane oxygenation transfer was made in Western countries for many years on roads, helicopters, and aircraft. Few centers can perform ECMO transfers. There are specialized centers for cannulating the patient at the referring hospital and transporting them back to their hospital.³ Few centers are providing ECMO for pediatric patients in our country.

Children are transferred to ECMO centers with traditional transport, and then, ECMO is often set up at receiving centers in our country. Extracorporeal cardiopulmonary resuscitation is a rescue procedure in which ECMO is urgently initiated in patients who have had a cardiac arrest (CA) and have failed conventional cardiopulmonary resuscitation (CCPR). As a result, the awareness and use of ECPR are increasing all over the world.

This study aimed to describe the clinical characteristics, management, and outcomes of venoarterial (VA) ECMO patients transported by aircraft and ground ambulance to a high-volume Turkish pediatric intensive care unit (PICU).

Materials and Methods

In this report, patients who underwent VA-ECMO and were transferred to our PICU by aircraft from 2016 to 2020 were evaluated retrospectively. Patient age, weight, body surface area (BSA), diagnosis, ECMO indication, ECMO course, hospital course, mode and reason of transport, complications on transport, and outcomes were analyzed. The local Institutional Ethics Committee approved this study [sign number is İ05-235-22]. Written informed consent was obtained from all patients’ relatives or their representatives, where necessary, from their legal authority. Our research was conducted according to the ethical principles of the World Medical Association Declaration of Helsinki.

Mobile Extracorporeal Membrane Oxygenation Team

Our pediatric mobile ECMO team consisted of a cannulating cardiovascular surgeon, a surgical fellow, an ECMO physician or pediatric intensivist, a perfusionist, and an ECMO scrub nurse.

Initiation of Venoarterial Extracorporeal Membrane Oxygenation

Venoarterial extracorporeal membrane oxygenation was established by the referring hospital personnel (3 patients) or by our mobile ECMO team (3 patients).

Extracorporeal Membrane Oxygenation Circuit

Extracorporeal Membrane Oxygenation circuit used in this study was a continuous flow centrifugal pump (JostraRotaflow®; Maquet Cardiopulmonary, Rastatt, Germany or Stockert Instrumente GmbH, Munchen, Germany), with a hollow fiber oxygenator (JostraQuadrox; Maquet Cardiopulmonary, Rastatt, Germany) or a polymethylpentene membrane (Dideco, Sorin Group, Mirandola, Italy).

Aircraft/Ground Ambulance Transport

In this case series, 5 patients were transported by fixed-wing aircrafts which were provided by the Turkish Ministry of Health (Cessna CJ2, Legacy 600, Learjet45). A commercial aircraft (Cessna CJ2) was used for 1 patient. Oxygen supplies were checked for the ECMO oxygenator and mechanical ventilation before transportation. Transport vehicles should also have an electrical supply sufficient for the ECMO pump and the heater. Suction systems, adequate lighting, and adequate space for the mobile ECMO team are also essential. The leader of the mobile ECMO team should also consider the safety of both the patient and mobile health officer, weather conditions, aircraft weight limitations, the potential cost of the aircraft, and valid passports for international flights.

Results

Between 2016 and 2020, 6 patients supported with VA-ECMO for ACS were transported to our PICU by aircraft. One of the cases was female. The median age was 89 (14-204) months. The patients were previously healthy and not immunocompromised. All patients were not with a remarkable medical history, except for corrected transposition of great arteries (TGA) (case 2). On hospital admission, 4 patients suffered from dyspnea, and the others had palpitation and tachycardia. One of the patient’s heart rhythm was atrial flutter, and the other’s heart rhythm was refractory ventricular tachycardia. Therefore, they received antiarrhythmic therapy. In all cases, patients were with cardiac failure. There were fulminant myocarditis in 4, dilated cardiomyopathy in 1, and TGA and atrial flutter in 1 of the study cohort. Three patients were found to have severe myocarditis whose laboratory testing was positive for H1N1, coronavirus, and adenovirus. Venoarterial extracorporeal membrane oxygenation was set up for all patients. Three patients were transferred to our PICU due to the lack of an ECMO facility in the referring center. During all transport, 1 pediatric intensivist, 1 pediatric vascular surgeon, 1 perfusionist, and 1 nurse existed with their equipment (manual roller pump, vascular clamps, and portable electric generator). Three patients were assigned to attend our pediatric heart transplantation program.

Extracorporeal membrane oxygenation cannulation of 3 patients was done by our pediatric cardiovascular surgeons. Average 11 hours after patient admission, patients arrived at our PICU. The median distance of travel for patients who were transferred to our hospital was 618 (407-955) km. The median duration of patients’ transportation was 2.6 (2.5-3) hours. The route of the patients who underwent VA-ECMO and were transferred to our PICU by aircraft is given in Figure 1. We did not see any adverse events during transport. There was no mortality during transport.

Figure 1.

Illustrating the route of the patients who underwent VA-ECMO and transferred to our PICU by aircraft on the map. VA-ECMO, veno-arterial extracorporeal membrane oxygenation; PICU, pediatric intensive care unit.

While undergoing ECMO, 2 patients received plasma exchange, and 3 patients received continuous renal replacement treatment due to multiorgan dysfunction syndrome (MODS) and fluid overload. Extracorporeal membrane oxygenation cannulation was performed in 4 patients for myocarditis and 2 patients for heart failure. Extracorporeal cardiopulmonary resuscitation was applied to 3 patients with myocarditis. Venoarterial extracorporeal cardiopulmonary resuscitation was set up periferically from the right carotid artery (CA) and internal jugular vein (İJV) in 3 patients and right femoral artery and femoral vein in 3 patients. Aircraft models used in the transfer of patients were Cessna CJ2, Learjet 45, and Legacy 600. The average ECMO duration was 8.8 (2-20) days. One patient received mechanical cardiac support with a left ventricular assist device because of a bridge to transplantation. Two patients died because of brain death after ECPR (cases 1 and 2), and 1 patient died from sepsis-related MODS (case 4). Femoral venoarterial ECMO was established at the 50th minute of CPR by the referring hospital personnel (case 4). The patient was transferred to our hospital on ECMO. Cases 1 and 2 were diagnosed with brain death by computed tomography angiography during follow-up. These 3 patients died after medical follow-up and 3 patients survived to hospital discharge. Characteristics of patients transported with ECMO support are given in Table 1.

Table 1.

Characteristics of the study population, ECMO cannulation, transport strategies, and outcomes.

Patients	Age	Weight (kg)	BSA (m2)	Indication	Initiation of VA-ECMO	Cannulation Configuration	Transport Distance (km)	Transport Duration (hours)	Aircraft Type Fixed-Wing Versus Commercial	Complication	ECMO Days of Weaned Patients	Outcome
1	22 months	10.8	0.49	ECPR	Mobile ECMO team	Right CA and IJV	720	2.5	Legacy 600	-	-	Death
2	14 years	44	1.36	Myocarditis	Referring hospital	Right FA and FV	407	3	Learjet 45	-	2 days	Brain death
3	14 months	8.6	0.41	Cardiac failure	Mobile ECMO team	Right CA and RJV	955	2.5	Cessna CJ2 (commercial)	-	7 days	Survived
4	17 years	57.2	1.6	ECPR	Referring hospital	Right FA and FV	505	2.5	Cessna CJ2	-	-	On the 20th–day of MODS
5	10 years	50	1.47	ECPR	Mobile ECMO team	Right CA and IJV	402	2.5	Learjet 45	-	8 days	Survived and bridged to LVAD
6	12 years	45	1.38	Cardiac failure	Referring hospital	Left FA and FV	720	3	Learjet 45	-	14 days	Survived

ECPR, extracorporeal cardiopulmonary resuscitation; VA-ECMO, veno-arterial extracorporeal membrane oxygenation; MODS, multiorgan dysfunction syndrome; LVAD, left ventricular assist device; CA, carotid artery; IJV, internal jugular vein; FA, femoral artery; FV, femoral vein.

Discussion

Our mobile ECMO team at our institution has successfully transported 6 pediatric patients on VA-ECMO over 5 years. Critically ill patients have been transported by an aircraft provided by the Ministry of Health with trained staff for more than 8 years in our country. Our case series is the first report on ECLS aircraft transport of pediatric patients in Turkey.

Bartlett et al⁴ mentioned the first aircraft transport on ECMO. After that successful transport, several reports were published. Extracorporeal membrane oxygenation transport can be done by ground ambulance, helicopter, and fixed-wing aircraft. In ELSO guidelines, ground transport is recommended for a distance up to 400 km, helicopter transport for a distance of 650 km, and fixed-wing aircraft transport in any distance.⁵ Broman and Frenckner³ defined 3 steps of ECMO aircraft transport, including transport to the referring hospital with personnel and equipment, procedures at the referring hospital, and transport back to own facility or to another ECMO center.³ The final assessment of the patient, cannulation, initiation of ECMO at the referring hospital, and the ECMO transportation are achieved by the mobile ECMO team which Broman and Frenckner indicate as primary transport.

If the referring hospital has the opportunity of cannulation of ECMO for the hemodynamically unstable patient, this transportation is named secondary transport. In a report from Canada, pediatric patients required ECMO cannulated before the ECMO transport team arrive at the referral center and then transported successfully.⁶ According to this study, since patients in need of ECMO are hemodynamically unstable and have a high probability of deteriorating in a short time, ECMO cannulation in the applied center shows a success rate in terms of survival. However, in an ECMO network of 10 intensive care units in Western France, it has been shown that there is no difference in morbidity and mortality between the admission to a center with ECMO cannulation and the critical patient admitted to a center where ECMO cannulation cannot be performed.⁷ But pediatric cannulation and ECMO follow-up need expertise.

The patient referred us to transfer to our unit for advanced medical support and cardiac transplantation not only for ECMO because there is not enough dedicated pediatric intensivist in our country but also because all of the patients were unstable to transport without ECMO. Our pediatric vascular surgeon made cannulation of 3 patients. A local adult vascular surgeon made 1 patient cannulate. There is not enough pediatric cardiovascular surgeon in our country, and adult cardiac surgeons do not want to cannulate pediatric patients because of lack of experience.

We had limitations during the transport process. Our unit does not have transport ECMO. We used our Ministry of Health’s fixed-wing aircraft in 5 patients and commercial flights in 1 patient (case 3). Our equipment is not designed for aircraft. In developed countries, ECMO transport is done by mobile ECMO and aircrafts designed for ECMO transport. Even doors of aircraft are not suitable for stretcher pass. Developed countries use modern techniques and devices for ECMO transport. Coppola et al⁸ reported the transport made by custom-designed mobile ECMO chart in 1 patient. Transport ECMO chart contains circuit tubing, bladder box venous outflow reservoir, roller pump, membrane oxygenator, inline blood gas monitor, cardiorespiratory monitor, heat exchanger, arterial and thrombus filter, and doppler flowmeter, mechanical ventilator, water heater/pump, and gas tanks. We cannot perform laboratory tests during flight because of not having laboratory devices. We could follow the patient with only monitors.

Our mobile ECMO team comprises at least 1 pediatric intensivist, 1 pediatric cardiovascular surgeon, and 1 perfusionist. Cardiovascular transplant team has significant aircraft experience from donor runs. Despite difficulties, our ECMO transport model is currently the first in our country.

We used fixed-wing aircraft for transporting of all patients. Aircraft models used in the transfer of patients were Cessna CJ2, Learjet 45, and Legacy 600. In case 1 and case 3 (Figure 2A), distance between cities is too long for the helicopter according to ELSO guidelines. Case 2 and case 4 (Figure 2B) are transferred by aircraft due to patients’ clinical urgencies. Also, there are few reports about aircraft transport across the world; most of the reports are transported by ground or helicopter. All flight costs of our patients are funded by state insurance.

Figure 2.

(A). Transportation of case 3. (B). Transportation of case 6.

Despite ECMO transportation being very important in some situations, the children who are under ECMO transportation have some risks of life-threatening events. We checked and recorded all hemodynamic, ECMO, and ventilation parameters during transportation.^7,8 We controlled patients’ hemodynamic parameters by observing clinically and monitoring arterial blood pressure, heart rate, and SpO2, and also we followed ECMO parameters such as rotation per minute and ECMO blood flow (liter per minute).

Main limitations of the study are its retrospective nature and single-center data, but this report is the first and extraordinary implementation in pediatric critically ill child transportation. More case series and multi-center studies should be planned.

Conclusion

Interhospital ECMO decision, cannulation, initiation, and follow-up require expertise and a multidisciplinary approach. Extracorporeal membrane oxygenation transport also needs an experienced mobile ECMO team and appropriate logistics. Early referral of patients with ACS to the hospital may prevent delays and adverse outcomes. Even though there are limitations, ECMO aircraft transport could be achieved without adverse events. Extracorporeal membrane oxygenation should be established in critical patients if needed, and patients should be transported to appropriate medical centers with mobile ECMO teams.