Key safety features of the ECMO apparatus are air bubble detectors; filters; and pressure, oxygenation and temperature monitors. The air bubble detectors identify micro-bubbles and, if found, turn off the pump. The filters screen for air or thrombi to prevent embolization. The monitors maintain against dangerous changes or spikes in the pressure of blood in the apparatus, and also monitor oxygen saturation and temperature of the blood before it returns to the patient.
CHALLENGES IN ECMO TRANSPORT
There are several challenges facing the interfacility transport service contemplating transportation of a patient on ECMO. Factors that must be considered include: likelihood of successful transportation with positive patient outcome, team composition and safety considerations for transport.
Most institutions that initiate ECMO are more than capable of fully caring for patients in their current settings. Reasons for transport include: suboptimal cardiothoracic physician staffing, centers that are not capable of initiating VAD therapies in the patient who has failed to wean, and institutions that do not have cardiac transplant capabilities. One must quickly realize that this cardiac patient is extremely ill and may not survive an interfacility transport. The agency providing transportation will have limited input into patient stability for transport, since the patient has been stabilized to the highest extent possible and usually requires therapies above those of the referring institution.
The transport agency does have a say in the manner and nature in which the transport team is configured. It would not be prudent to transport a patient using only the SCTU model described at the beginning of this article. Because of the clinical instability of the patient and the complexity of the ECMO apparatus, it is appropriate to augment the transport team with additional staff to ensure the highest likelihood of a safe transport with positive patient outcome. Additional staff may include:
- Cardiothoracic surgical MD or physician assistant (PA). Due to the inherent risk of exsanguination in the event of an inadvertent decannulation, it is appropriate for a cardiothoracic surgical MD or PA to accompany the patient on the transport.
- Certified clinical perfusionist (CCP). The "perfusionist" is responsible for the safe operation and troubleshooting of the ECMO apparatus. Regardless of the transport nurse's comfort level with ECMO, a CCP should always be part of an ECMO transport team.
- Anesthesiologist or certified registered nurse anesthetist (CRNA). Anesthesia professionals are extremely familiar with the unique airway, oxygenation and ventilation needs of the ECMO patient. The anesthesiologist and/or CRNA are also very involved in circulatory support of the patient.
- Additional lifting assistance. If available, an additional ambulance crew should be detailed to assist in physical movement of the patient and equipment, as this task can be cumbersome for clinical staff alone.
In addition to team composition, the transporting agency has the ultimate say and responsibility for safely transporting the patient from the referring facility to the receiving facility. Agencies that are already prepared for or accustomed to transporting isolettes, IABPs and VADs may have an easier time at initially transporting the ECMO patient without advanced warning or preparation. In general, these agencies are used to working with non-transport clinicians and have a general understanding of safe transport of such devices. The transporting agency must remember that the ECMO apparatus is generally larger than a transport VAD, but may be as large as a full-size non-transport VAD console. The physical size and weight of the ECMO apparatus may be its only limiting factor for safe transport. Vehicles equipped with hydraulic lifts and floor-mounted attachment points, commonly referred to as Bucher mounts, are preferred, as these features assist in safely lifting and securing the ECMO apparatus. It is critical that all devices introduced into the rear of the ambulance be strapped in place to prevent inadvertent movement during transport. This will provide a safer environment for both the patient and medical staff in the ambulance. Additionally, all team members must have the ability to sit and be seat-belted while the vehicle is in motion.