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In addition to IABPs, there are other devices that are inserted percutaneously for temporary support of patients in acute cardiogenic shock. Unlike the IABP that improves the conditions for left ventricular function, these percutaneously placed left ventricular assist devices (pLVAD) directly assist the left ventricle. Among the most common of these devices is a transaortic intraventricular pump (Impella®) and extracorporeal pumps, including a left atrium to aorta pump (TandemHeart®) and right atrium to aorta pump (ECMO) [4].

The transaortic intraventricular pump is an axial flow pump that is inserted into the femoral artery and advanced in a retrograde fashion through the aortic valve and into the left ventricle. The device sits across the aortic valve and contains an inflow and outflow orifice. Between them is an impeller, a propeller that provides continuous blood flow from the left ventricle to the ascending aorta. Correct catheter positioning across the aortic valve is necessary for pump function. Blood is pumped from the left ventricle into the aortic root, unloading the left ventricle. This increases cardiac output and mean arterial pressure and decreases left ventricular end‐diastolic pressure, myocardial workload, and oxygen consumption [4].

The power connections for the pump motor and sensors are all contained within the catheter and connected to an external console that controls the pump and purge system. The controller console monitors both the catheter position and function of the impeller. It does not require pressure timing or electrocardiogram timing like the IABP, making it ideal for patients with arrhythmias. In addition to providing information on the location of the catheter and the flow rate of the impeller, the controller console also provides alarms related to suction events and purge pressure issues [4].

EMS clinicians are most likely to encounter these devices during interfacility transport of critical care patients. They are generally placed in patients with cardiogenic shock following acute myocardial infarction. Like the IABP, the positioning of the catheter is critical. The catheter location should be confirmed visually as sutured at a specific depth, in addition to reviewing the placement signal on the controller console. If repositioning of the catheter needs to be performed, the referring physician should do it prior to attempting transport. If the catheter becomes dislodged during transport, it should not be repositioned. Alternative support may be required. The pump also contains a purge system that prevents blood from entering the motor. It should be closely monitored during transport. Only transport teams knowledgeable about these devices should transport them without a specialist to manage the device. Knowledge about how to interpret the placement signal and how to troubleshoot the alarms by administering intravenous fluids, titrating vasopressors, or adjusting the flow of the impeller is important to a safe transport [5].

Patients with a transaortic intraventricular pump have been safely transferred between hospitals [1]. It seems likely that EMS clinicians providing critical care transport will encounter more patients with similar devices over time. There is some uncertainty about mortality outcome benefits compared to, for example, IABP therapy. However, technological advances continue, and some centers preferentially use transaortic microaxial‐flow LVADs with acceptable mortality and complication rates in place of more invasive devices [6, 7].

The left atrium to aorta extracorporeal centrifugal pump is placed percutaneously through the femoral vein. The cannula is passed via a transseptal puncture through the intra‐atrial septum from the right atrium to left atrium where oxygenated blood is aspirated. A second outflow cannula is placed that returns the blood to the femoral artery. Advantages compared to the IABP and transaortic intraventricular pump are improved unloading of the left ventricle with improved cardiac output. This pump also bypasses the left ventricle and aortic valve and can therefore be useful for patients with left ventricular thrombus or aortic stenosis [8]. Like the transaortic intraventricular pump, this device results in improved hemodynamic profiles but with less certain short‐term mortality benefits. The disadvantage of this extracorporeal centrifugal pump is the transseptal puncture, requiring a surgeon or experienced interventional cardiologist for placement. This approach also increases complications associated with potential iatrogenic cardiac injury [8]. Similar to other devices, an understanding of how to troubleshoot this device and manage the complications is imperative for safe transport.