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Remote ECLS-Implantation and Transport for Retrieval of Cardiogenic Shock Patients
ARTICLE IN PRESS Air Medical Journal ■■ (2017) ■■–■■
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Original Research
Remote ECLS-Implantation and Transport for Retrieval of Cardiogenic Shock Patients Sabina P.W. Guenther, MD 1,*, Stefan Buchholz, MD 1, Frank Born, MCt, ECCP 1, Stefan Brunner, MD 2, René Schramm, MD, PhD 1, Dominik J. Hoechter, MD 3, Vera von Dossow, MD 3, Maximilian Pichlmaier, MD, MA (Cantab) 1, Christian Hagl, MD 1, Nawid Khaladj, MD, MBA 1 1 2 3
Department of Cardiac Surgery, University Hospital Munich, Ludwig-Maximilian-University, Marchioninistr. 15, 81377 Munich, Germany Medical Department I (Cardiology), University Hospital Munich, Ludwig-Maximilian-University, Marchioninistr. 15, 81377 Munich, Germany Department of Anesthesiology, University Hospital Munich, Ludwig-Maximilian-University, Marchioninistr. 15, 81377 Munich, Germany
A B S T R A C T
Objective: Extracorporeal life support (ECLS) emerges as a salvage option in therapy refractory cardiogenic shock but is limited to highly specialized tertiary care centers. Critically ill patients are often too unstable for conventional transport. Mobile ECLS programs for remote implantation and subsequent air or ground-based transport for patient retrieval could solve this dilemma and make full-spectrum advanced cardiac care available to patients in remote hospitals in whom shock otherwise might be fatal. Methods: From December 2012 to March 2016, 40 patients underwent venoarterial ECLS implantation in remote hospitals with subsequent transport to our center and were retrospectively analyzed. The mobile ECLS team was available 24/7, implantation was performed percutaneously bedside, and compact support systems designed for transport were used. Results: Twenty percent of the patients were female; the mean age was 55 ± 10 years, and the mean Interagency Registry for Mechanically Assisted Circulatory Support score was 1.3 ± 0.5. Patient retrieval was accomplished via ground-based (n = 29, 72.5%, mean distance = 27.9 ± 29.7 km [range, 5.6-107.1 km]) or air (n = 11, mean distance = 62.4 ± 27.2 km [range, 38.9-116.4 km]) transport. No ECLS-related complications occurred during transport. The ECLS system could be explanted in 65.0% (n = 26) of patients, and the 30-day survival rate was 52.5% (n = 21). Conclusion: Remote ECLS implantation and interfacility transport on ECLS are feasible and effective. Interdisciplinary teams and full-spectrum cardiac care are essential to achieve optimal outcomes. Rapidresponse ECLS networks have the potential to substantially increase the survival of cardiogenic shock patients. Copyright © 2017 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.
The achievement of maximum survival rates and the minimization of morbidity in cardiogenic shock patients frequently require the full spectrum of interdisciplinary cardiac care. In several analyses including our own preliminary results, extracorporeal life support (ECLS) was shown to provide immediate and full cardiopulmonary support with subsequent hemodynamic stabilization and a favorable outcome in critically ill patients in whom conventional therapy had failed.1-6 This therapeutic approach requires substantial infrastructure, specifically trained personnel, and suitable interdisciplinary concepts
* Address correspondence to: Sabina P.W. Guenther, MD, Department of Cardiac Surgery, Ludwig-Maximilian-University, University Hospital Munich, Marchioninistr. 15, 81377 Munich, Germany. E-mail addresses: [email protected] (S.P.W. Guenther).
and is therefore limited to specialized tertiary care centers.2 However, the transport of patients in severe cardiogenic shock imposes a substantial risk. Mobile ECLS teams offer the potential of providing the full spectrum of the latest, advanced, and high-end interdisciplinary cardiac care available to patients in remote hospitals in whom cardiogenic shock otherwise might potentially be fatal. Even though experience in ground-based retrieval exists to some extent, air transport requires compliance with specific regulations.7 Here, we describe our concept and protocol, report our initial results, and outline how to establish a suprainstitutional rapid-response ECLS program. Methods The technique of ECLS and the management strategies implemented at our center have been described previously. 1,4,8 We
1067-991X/$36.00 Copyright © 2017 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amj.2017.06.007
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All necessary materials for the cannulation, establishment, and sustainment of ECLS during transport are compactly prepacked in a backpack, ready to use at all times, and located in a storage facility in the emergency department of our center in closest proximity to the emergency service driveway (Fig. 1). The backpack contains disinfection, sterile sheets, gowns, gloves, caps and masks, sets for arterial and venous cannulation including cannulas of different sizes, distal limb perfusion catheters, connectors, clamps, scissors, additional tubing, heparin, saline, syringes, sutures, a needle holder, and other material for sufficient fixation of cannulas and the device as well as wound dressing and protocols. Additionally, a power supply extension cable, an emergency hand drive, and an additional pump head are contained in the standard backpack. Altogether, all necessary materials including surplus and backup are taken by the mobile ECLS team, resulting in the team being self-sufficient and independent of local conditions or circumstances, even in case of unexpected incidents. Team Our mobile ECLS team consists of a cardiac surgeon specifically experienced in cannulation for ECLS and the management of ECLS including the full spectrum of intensive care and a senior perfusionist specifically trained in setting up and handling the mobile ECLS device, assisting during cannulation, and managing the extracorporeal circuit during transport. If feasible, a cardiac surgeon and/ or perfusionist in training will additionally accompany the team for educational reasons. Figure 1. The mobile ECLS system (LifeBox, Sorin Group, Munich, Germany) including the drive unit (white arrow), perfusion unit and transport mounting (black arrow) as well as the backpack (black star) and cannulas (white star).
commenced the retrieval of cardiogenic shock patients with onsite ECLS implantation and subsequent transport in December 2012 to provide support for patients in remote hospitals and thus equitable access to full-spectrum and last-resort interdisciplinary cardiac care. Support is provided 24 hours a day, 7 days per week, throughout the year. Besides substantial expertise in the placement and management of ECLS including bail-out concepts, adequate patient selection criteria, suitable protocols, and considerations on material and personnel are needed for this specific ECLS setting. Equipment and Technical Considerations Compact support systems specifically designed for transport have been developed. Requirements include small size and low weight, simplicity, easy handling, and sufficient battery capacity. The transport system used in our center (LifeBox; Sorin Group, Munich, Germany) consists of a drive unit, perfusion unit, and transport mounting (Fig. 1). The drive unit includes the drive, a control panel, and the battery. The perfusion unit consists of a centrifugal pump (Revolution 5, Sorin Group) and an oxygenator (ECCO; Eurosets, Medolla, Italy). It is phosphorylcholine coated, and the priming volume is 640 mL. The maximum revolutions per minute are 3,500/ min, and the maximum blood flow achievable is 7 L/min.7 The weight is approximately 20 kg, and the battery capacity suffices, depending on the workload, for up to 180 minutes. The pump head is licensed for 5 days of usage and is thus the limiting component. The pump is compatible with the standard stationary ECLS (Stöckert Centrifugal Pump Console, Sorin Group) and cardiopulmonary bypass systems (S5, Sorin Group) used in our department and may be switched upon arrival. Because no new circuit, pump, or kit is needed, the critical low-flow time when switching the console can be reduced to a minimum.
Means of Transport Technical requirements to be met by a suitable means of transport are adequate power supply for the extracorporeal circuit (ie, 220 V); a reliable and independent oxygen source; the ability of invasive blood pressure measurement; a suitable ventilator; and sufficient space for the emergency medical services crew, the mobile ECLS team, and the specific material and options for fast and safe (un)loading as well as for securing the equipment, ECLS circuit, and patient.9 Commonly, these are fulfilled by standard intensive care ambulances and intensive care helicopters. Additional factors to be taken into consideration include noise, climate control, adequate lighting, ceiling height, and availability of compressed air and suction.9 The overall transport time may exceed the perfusion unit’s battery capacity, and, especially in rural areas, ambulances may not be equipped with 220 V.7 For air transport, additional regulations and air worthiness criteria need to be taken into consideration as given by appropriate state, national, or international regulatory agencies, whereas for Europe those provided by the European Aviation Safety Agency apply, as described earlier.7,9 Specifically, securing the ECLS system in a helicopter needs to comply with gravitational demands (Table 1).7 For that purpose, a specifically designed mounting system is used (Fig. 2). It was secured on the base plate of the helicopter in air transport and attached to the stretcher during ground-based transport (Fig. 3).
Table 1 Extracorporeal Life Support System Mounting Devices for Usage in Helicopters Need to Comply With Specific Gravitational Demands Degrees of Freedom
Acceleration (G)
Upward Forward Sideward Downward Backward
4 16 8 20 1.5
G = gravitational constant. Modified with permission.7
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a
3
b
Figure 2. The transport mounting device: an (a) oblique front view and (b) bottom view.
a
b
Figure 3. (a) Fastening the perfusion unit onto a conventional stretcher and (b) the bottom plate of a Eurocopter 145 (Airbus Helicopters, Donauwörth, Germany) using the mounting device.
Protocol and Workflow The referring clinic contacts our department via a telephone call with immediate physician-to-physician communication available at all times. The medical history is obtained by the physician on duty, and standardized criteria are evaluated. Afterward, the case is concisely discussed with the respective attending. Patients are considered for venoarterial ECLS in case of severe refractory and conventionally intractable cardiogenic shock. In general, this definition is met in cases in which there is a requirement of increasing doses of inotropes and/or vasopressors to maintain adequate hemodynamics with evidence of end-organ hypoperfusion despite optimal care.1 In extreme cases, this implies ongoing cardiopulmonary resuscitation. Additionally, special attention is paid to the etiology and onset of cardiogenic shock, age, comorbidities, general condition, current status including catecholamine support, pH, lactate level, and secondary organ failure. In case of resuscitated patients, ischemic time, duration, and quality of cardiopulmonary resuscitation are key factors. Almost no ultimate exclusion criteria exist in these extreme situations or emergency settings, and evaluation is performed on an individual basis. In case eligibility for ECLS cannot be determined remotely or in case of doubt, the mobile ECLS team is sent out for direct evaluation on-site. The team is ready to depart within 5 to 10 minutes during working hours and a maximum of 20 to 30 minutes on call. Preparation times equal those for in-house implantation, but waiting for the means of transportation might have to be taken into consideration. Prompt departure is indispensable to ensure timely arrival and to reduce the risk of further deterioration of the patient’s condition. After the decision to send out the mobile ECLS team has been made, the physician on duty contacts the local rescue coordination center. Consequent and stringent organization and preparation are of enormous importance. Depending on the distance to the referring
hospital and the availability of landing places, time of day, weather conditions, current status of the patient, and availability, the suitable means of transportation is selected by the dispatcher in coordination with the physician on duty. Because of practical considerations, usually the same means of transport is used for both directions. In case of expected delays because of current unavailability of both intensive care ambulance and helicopter or in case of rapid deterioration of the patient’s condition (eg, ongoing cardiopulmonary resuscitation), the team may also be transported to the referring clinic using any rescue service standard car because of the compactness of the equipment. In parallel with sending out the team, recommendations for medically stabilizing the patient and instructions for preparation for ECLS establishment are given. The latter include, if not previously established, large lumen central venous catheter insertion, preferably into the internal jugular vein, and arterial catheter insertion into the right radial artery as well as providing 3 units of packed red blood cells if available. After arrival, re-evaluation on-site is performed while preparations for cannulation are parallelized in order to reduce low output und hypoperfusion time. Whenever feasible, the patient’s or relative’s consent is obtained. If no patient’s advanced directive was available, implantation was discussed and performed according to the patient’s supposed wishes in compliance with German law. Details of ECLS implantation and management have been described earlier and are adapted for remote implantation.1,5,10,11 Cannulation is feasible in intubated and ventilated patients but also in conscious patients. Percutaneous cannulation of the femoral artery and vein is performed using the Seldinger technique. This technique offers the advantage of fast cannulation, which is feasible bedside without surgical cut down.1 Imaging modalities are not mandatory. Briefly, after adequate disinfection and sterile covering of the implantation site, the femoral artery and vein are cannulated.
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ECLS request Patient evaluation
Patient considered for ECLS Sending out mobile ECLS team
Instructing referring clinic to prepare patient for ECLS establishment
Arrival in referring clinic Re-evaluation
Preparation for cannulation
Establishment of ECLS Stabilization
Air transport
Preparation for transport
Ground transport
Figure 4. The work flow for remote ECLS implantation and subsequent ground-based or air transport for the retrieval of patients in severe cardiogenic shock.
The sizes of the cannulas are selected according to the patient’s body surface area and anticipated target flow. Routinely, we used 17F arterial and 23F or 25F venous cannulas for patients with body weights above 70 kg as well as 15F arterial and 21F venous cannulas for body weights below 70 kg (Maquet Arterial HLS Cannula [MAQUET Cardiopulmonary AG, Rastatt, Germany] and Maquet Venous HLS Cannula [MAQUET Cardiopulmonary AG], respectively). Additionally, to ensure adequate distal leg perfusion and avoid lower limb ischemia, a distal limb perfusion catheter is inserted into the superficial femoral artery (Radiofocus Introducer, 6F; Terumo, Eschborn, Germany).1 After ECLS establishment, vasopressors (ie, norepinephrine and vasopressin) were reduced first according to the hemodynamic situation. To preserve left ventricular (LV) ejection and prevent ventricular distension and pulmonary congestion, inotropic support was maintained using epinephrine as the first-line therapy and milrinone or dobutamine in case of increased vascular resistance. If necessary, additional means for LV unloading were evaluated upon arrival in our center.1,12 After ECLS implantation and stabilization of the patient, preparation for transport is performed thoroughly with a special focus on securing the tubing, pump, and oxygenator as well as the transition of medication and ventilation to the ambulance’s or helicopter’s devices. Specific aspects to be considered during transport include sudden movements (vertically or horizontally) altering the patient’s or circuit’s position, cannula movement affecting the cannula entry site or positioning of the cannula’s tip, kinking, compression or entangling of the circuit, and movement or trauma of the equipment.9 The most deleterious complications during transport are accidental decannulation and circuit failure or disruption.13 Especially when moving the patient, it is 1 person’s dedicated task to manually secure cannulas and tubing. The perfusion unit can easily be attached to any standard stretcher using the specifically designed mounting device (Fig. 3), minimizing the risk of dislocation. The device is also suitable and approved for fixation in helicopters as explained previously.7 After arrival at our center, appropriate diagnostics and therapy were triaged and commenced according to the underlying pathology. In case of myocardial ischemia, the patient was transferred to the catheterization laboratory. In case the etiology of cardiogenic shock was unclear, concomitant pathologies had to be ruled out, or if cannula positioning had to be verified, whole-body computed
tomographic imaging was performed. In case of previously established diagnosis and completed diagnostics, the patient was directly transferred to the intensive care unit. Giving advanced notice of the estimated arrival time and keeping close contact to the responsible team on-site help to avoid a waiting time and ensure smooth processes. After arrival, the mobile ECLS transport system is switched to our standard stationary system (Stöckert Centrifugal Pump Console). The transport unit is immediately set up for potential retrievals to ensure constant operational readiness. A follow-up for checking the circuit and patient is performed by both the surgical ECLS team as well as a perfusionist at least once per day. A detailed work flow is depicted in Figure 4. Costs and Reimbursement In the German health care system, costs for transportation are calculated according to standardized accounting schemes. Transport to centers of a higher level of care is reimbursed via the health care insurance system. Because the helicopter is positioned at our center, no additional costs arose from the pickup of the ECLS team and material in these cases. Costs for ECLS itself are reimbursed via supplementary fees. Patients, Data Acquisition, and Statistics From December 2012 to March 2016, 40 patients underwent venoarterial ECLS implantation in remote hospitals with subsequent transport to our center and were retrospectively analyzed. Data were collected from the patients’ health care records with a special focus on documentation of transport. The duration of survival was determined from ECLS implantation date to death and at the 30-day follow-up. Retrospective data acquisition and analysis were approved by the institutional ethics committee, with individual patient’s consent being waived because of the sole retrospective design of the study. Categoric variables are presented as numbers and percentages; continuous variables are given as mean ± standard deviation. Because of the limited number of patients and the focus on infrastructure and management, only descriptive statistics are provided. Results A total of 40 patients (20.0% female, mean age 55 ± 10 years) were included. Patient retrieval was accomplished via ground-based
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Table 2 Patients’ Characteristics, Transport Details, and Outcome Variable Age (y), mean ± SD Female, n (%) INTERMACS score, mean ± SD Previous cardiopulmonary resuscitation, n (%) Ongoing cardiopulmonary resuscitation, n (%) Etiology, n (%) ACS CM Myocarditis PE Amniotic fluid embolism Prinzmetal angina Acute mitral regurgitation Dysfunction of prosthetic mitral valve Vasculitis Implantation and transport During on-call duty hours, n (%) Distance (km), mean ± SD (range) Outcome, n (%) Explantation 30-day survival
All Patients
Ground Transport
Air Transport
N = 40 55 ± 10 8 (20.0) 1.3 ± .5 28 (70.0) 7 (17.5)
n = 29 (72.5%) 56 ± 7 6 1.2 ± .4 22 4
n = 11 (27.5%) 52 ± 15 2 1.5 ± .5 6 3
22 (55.0) 6 (15.0) 3 (7.5) 3 (7.5) 1 (2.5) 1 (2.5) 2 (5.0) 1 (2.5) 1 (2.5) 23 (57.5) 37.3 ± 32.8 (5.6-116.4) 26 (65.0) 21 (52.5)
17 4 3 1 1 1 0 1 1 18 27.9 ± 29.7 (5.6-107.1) 20 16
5 2 0 2 0 0 2 0 0 5 62.4 ± 27.2 (38.9-116.4) 6 5
ACS = acute coronary syndrome; CM = cardiomyopathy; INTERMACS = Interagency Registry for Mechanically Assisted Circulatory Support; PE = pulmonary embolism; SD = standard deviation.
(n = 29, 72.5%) or air (n = 11) transport. The mean Interagency Registry for Mechanically Assisted Circulatory Support profile was 1.3 ± 0.5; predominant etiologies were acute coronary syndrome (55.0%) and decompensated cardiomyopathy (15.0%). The mean distances accomplished were 27.9 ± 29.7 km (range, 5.6-107.1 km) for groundbased transport and 62.4 ± 27.2 km (38.9-116.4 km) for air transport. In 52.5%, the referring clinic was closer than 25 km to our center; in 20.0%, it was more than 75 km away. Initially limited to hospitals cooperating with the cardiosurgical department of our center, retrieval was extended to any remote clinic after the program had become established throughout the region. With increasing experience, more air transports were performed (36.4% within the last 3 months). Seven patients (17.5%) had been on intra-aortic counterpulsation, and 3 patients (7.5%) were on Impella (Abiomed, Danvers, MA) support either at ECLS implantation or during the prior course. In all cases, hemodynamic support was insufficient to prevent further hemodynamic deterioration. In case another device was in place at the time of ECLS establishment, it was either kept for additional LV unloading or removed upon ECLS deployment or after arrival at our center, respectively. During cannulation and placement of ECLS, in 1 case malpositioning of the arterial cannula without backflow occurred. The contralateral artery was cannulated successfully. The initial cannula was removed after arrival in our center with surgical revision the following day. In 3 cases, open surgical implantation of the distal limb perfusion catheter was performed in our center because of impossible or rejected insertion on-site with subsequent ischemia and compartment syndrome in 1 patient. In 1 case of air transport, technical failure of the invasive arterial blood pressure monitoring device occurred shortly before landing and was switched to another unit right after landing. Except for this incident, no adverse events occurred during transport, and all patients were transferred to our center safely. The ECLS system could be explanted in 65.0% (n = 26) of patients, and 30-day survival was 52.5% (n = 21). Six of the survivors (6/21, 28.6%) experienced neurologic complications (2 with hypoxic brain injury, 2 with hypoxic brain injury and multiple embolic/ischemic strokes, 1 with a sub-/ epidural hematoma, and 1 with prolonged phase of awakening); 5 of them had been resuscitated. Four patients recovered with no,
mild, or moderate residual neurologic impairment. Two patients suffered severe neurologic damage with a limited prognosis. The overall survival (in-house and remote implantations) during the same time span was 42.7%. However, we recently implemented the concept of extracorporeal cardiopulmonary resuscitation, and more than one third of the in-house patients underwent implantation during ongoing cardiopulmonary resuscitation. Detailed information on patients’ characteristics and outcome is given in Table 2. Discussion ECLS has gained increasing acceptance as a rescue therapeutic option for patients in otherwise intractable cardiogenic shock.1,3,14,15 However, hemodynamic instability, end-organ dysfunction, necessity of high-dose catecholamine treatment, and other factors render the majority of these patients inconsiderable or at high risk for conventional interfacility intensive care transport to tertiary care centers providing the full spectrum of interdisciplinary cardiovascular care including ECLS.14,15 Changes in health care services because of economic considerations include progressive specification and centralization. Mobile ECLS teams with the ability of remote implantation have the potential to provide a suitable solution for this dilemma. Patients in remote hospitals in whom conventional therapy has failed and cardiogenic shock might thus be fatal via that approach can gain access to stabilization and the full spectrum of advanced heart failure management. ECLS may serve as a bridging therapy to treatment or decision, recovery, assist device implantation, and, in sporadic cases, as a bridge to transplantation.1 ECLS may exceed cardiopulmonary support capacities of other percutaneous assist systems that have been analyzed in cardiogenic shock such as intra-aortic counterpulsation (intra-aortic balloon pump), the Impella pump, or other devices.1,16,17 Earlier publications to a vast extent mainly reported on remote venovenous extracorporeal membrane oxygenation (ECMO) implantation or the retrieval of pediatric patients or comprised small numbers of patients.13,18-22 However, suprainstitutional area-wide referral programs for venoarterial ECLS have only recently emerged. With progress in technology and device safety as well as increasing experience of ECLS centers, therapeutic efforts have been expanded to those patients in remote hospitals. Compact mobile
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support systems facilitate the handling and management of the device, and percutaneous implantation techniques allow for bedside cannulation without the necessity of surgical cut down or imaging modalities.1,7 The Extracorporeal Life Support Organization provides guidelines for ECMO transport that cover all modes of extracorporeal circulation for circulatory support or oxygenation. The guidelines highlight that substantial expertise in ECMO care and interfacility transport is necessary before establishing mobile programs and providing practical considerations.9 In a large prospective proof-of-concept pilot study conducted by Beurtheret et al15 from January 2005 to December 2009 in the Greater Paris area, 87 patients were remotely placed on ECLS, 41% after cardiac arrest and 13 while being resuscitated. Seventy-five patients were successfully transferred to the tertiary care center after stabilization, and 32 survived to hospital discharge, resulting in an overall survival rate of 37%. Twelve patients (14%) were not transported because of hemodynamic instability and died within the further course. Transfer was performed within the first 24 hours in most cases; in 1 case, device dysfunction with the necessity of temporary manual assistance occurred during transport. Aubin et al23 recently reported on 115 patients who were remotely placed on ECLS (median distance to implantation site = 2.1 km, in 77% implantation under cardiopulmonary resuscitation, 44% survival to discharge) and proposed a decision tree model for triaging the patients according to survival-based predictors.23 Biscotti et al14 published their results of 100 transports (median distance = 16 miles, 3 by fixed wing aircraft) from 2008 through April 2014; however, only 19 patients had received venoarterial support, and 2 received venovenousarterial support. Initially only including highly selected patients and short distances, they extended their inclusion criteria with gaining experience. There was 1 case of accidental decannulation with a need of recannulation and 1 case of pump console failure before transport with no intratransport malfunctions.14 Throughout a time span of more than 3 years, we retrieved patients in severe refractory cardiogenic shock with remote ECLS implantation. Forty patients were transported to our center via air or ground-based transport after the establishment of ECLS. We established a formal, protocol-based system with procedural standardization and protocol refinement with gaining experience. Altogether, we experienced no ECLS-related complications during transport. As explained earlier, the means of transportation was selected according to weather conditions, availability, distance, and local circumstances. Both air and ground-based transport of patients on ECLS seem to be safe if performed by an experienced team. Detailed analyses of the impact on survival remain to be awaited. Our mobile ECLS program covers both the densely populated area of the city of Munich and the rural surroundings. Because of that, more than 50% of the referrals were from hospitals located less than 25 km away from our center. This underlines that even in densely populated regions without mobile ECLS retrieval only a limited number of patients would have access to this potentially lifesaving treatment option.15 Because of growing recognition of this therapeutic approach, the number of referring centers subsequently increased, leading to an expansion of the network over time. Raising the awareness of referring hospitals will continue to be necessary. In comparison to in-house implantation, timing in the setting of remote patient retrieval gains importance. Even in ideal settings, time to cannulation needs to be considered. In patients with out-of-hospital cardiac arrest, door to ECLS implantation time correlated with the outcome. 24 Because critical low output and hypoperfusion or even the necessity of cardiopulmonary resuscitation have to be avoided, the emergency call has to be made in a timely manner. In case no suitable intensive care ambulance or helicopter is immediately available, our team can rapidly depart via any conventional rescue service car because of the compactness of
the material and console in order to expedite arrival at the referring facility.9 With gaining experience, we performed more air transports, which may be time-saving, especially for long-distance transports. The availability of air transport does not only depend on weather conditions but also may be limited during nighttime. In our collective, the majority of remote implantations were performed during on-call duty times. Thus, remote hospitals should be encouraged to place the emergency call as soon as possible. We achieved acceptable 30-day survival and neurologic outcome rates in these severely ill patients despite the majority of the patients having been resuscitated. These results are in line with or even slightly above those of other authors.15,23 Even though complication rates are low, remote cannulation and subsequent transport are highly complex, and adverse events can be life-threatening. Difficulties experienced during cannulation likewise occur during inhouse ECLS placement and underline the necessity of experience, fundamental skills, and concepts including bail-out options. This is even more relevant for cannulation in remote hospitals because alternative options, such as surgical cut down, are limited, and because of the lack of trained staff, equipment, and diagnostic as well as therapeutic options, potential risks and consequences are magnified when leaving the familiar environment of the home institution.13 In the setting of remote cannulation, safe access and stabilization of the patient will be the main priorities, whereas advanced open surgical or interventional procedures will usually be performed after arrival at our center. Even though the exact composition of the team and the roles of each team member vary among different centers, these considerations in our opinion imply that, first, a cardiac surgeon not only being specifically trained in cannulation techniques and bail-out concepts but also in the management of patients on ECLS and, second, a perfusionist who is highly competent in handling mobile systems are indispensable as also outlined in the recommendations of the European Association For Cardio-Thoracic Surgery.2 Third, for optimal subsequent patient care, an interdisciplinary team focused on the management of cardiogenic shock and ECLS is required, and centers offering ECLS retrieval should provide the full spectrum of cardiopulmonary care including ventricular assist device implantation and transplantation programs. Provided that fundamental and dedicated expertise is ensured, remote ECLS cannulation and subsequent transport in the vast majority of the cases are safe, feasible, efficient, and effective. The implementation of area-wide ECLS retrieval programs provides an important resource for regional hospitals and offers a salvage concept for patients in therapy refractory cardiogenic shock that otherwise might be lethal. Because sufficient expertise and infrastructure as well as efficient resource use are required to operate these programs, centralization of this therapeutic concept to highly specialized centers seems to be a rational model.14 However, institutional standards as well as an adequate minimum caseload need to be defined.9 This is further underlined by caseload outcome correlations.21 Cost-benefit analyses and number needed to treat calculations are to be awaited and will be necessary to optimize processes as well as health care resource use. Similarly, scoring systems to predict in-hospital mortality while allowing for risk stratification of remote patients are difficult to establish but will be needed to further refine and optimize treatment regimens as well as inclusion criteria. Even though the survival after veno-arterialECMO score has recently been proposed by Schmidt et al,25 this score is not specifically designed for remote ECLS implantation and also did not include patients with implantation during ongoing cardiopulmonary resuscitation. Thus, for the setting of remote ECLS implantation and especially distant site patient evaluation, more specific scores are needed.23,25 Lastly, safety and quality indicators should be defined and established.
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This report has limitations inherent to any retrospective analysis limiting its power. Randomized and multicenter trials will be needed to fundamentally prove the validity of the concept of mobile ECLS programs. Long-term outcomes analyzed in large patient collectives need to be awaited. Additionally, the patients analyzed in this study represent a preselected collective because the total number of requests, of patients who died before arrival of the mobile team as well as patients who did not have an indication for ECLS implantation upon arrival have not been included in the analysis. However, the main focus of this report was methodologic. In conclusion, interfacility transport of patients on venoarterial ECLS is feasible, safe, and reliable and distinctly expands the therapeutic options for patients in severe conventionally intractable and potentially fatal cardiogenic shock in remote hospitals. A welltrained team, clear protocols, and interdisciplinary consecutive patient care are required to achieve an optimal outcome. Specifically, bail-out strategies for potential complications during both cannulation and transport need to be considered in advance. References 1. Guenther SP, Brunner S, Born F, et al. When all else fails: extracorporeal life support in therapy-refractory cardiogenic shock. Eur J Cardiothorac Surg. 2016;49:802–809. 2. Beckmann A, Benk C, Beyersdorf F, et al. Position article for the use of extracorporeal life support in adult patients. Eur J Cardiothorac Surg. 2011;40:676–680. 3. Abrams D, Combes A, Brodie D. Extracorporeal membrane oxygenation in cardiopulmonary disease in adults. J Am Coll Cardiol. 2014;63:276–2778. 4. Sattler S, Khaladj N, Zaruba MM, et al. Extracorporal life support (ECLS) in acute ischaemic cardiogenic shock. Int J Clin Pract. 2014;68:529–531. 5. Sakamoto S, Taniguchi N, Nakajima S, et al. Extracorporeal life support for cardiogenic shock or cardiac arrest due to acute coronary syndrome. Ann Thorac Surg. 2012;94:1–7. 6. Haneya A, Philipp A, Diez C, et al. A 5-year experience with cardiopulmonary resuscitation using extracorporeal life support in non-postcardiotomy patients with cardiac arrest. Resuscitation. 2012;83:1331–1337. 7. Born F, Albrecht R, Boeken U, et al. Extra corporeal life support: technical requirements and latest developments. Heart-lung-renal assistance. Z Herz Thorax Gefäßchir. 2011;25:370–378. 8. Guenther S, Theiss HD, Fischer M, et al. Percutaneous extracorporeal life support for patients in therapy refractory cardiogenic shock: initial results of an interdisciplinary team. Interact Cardiovasc Thorac Surg. 2014;18:283–291.
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9. Dirnberger D, Fiser R, Harvey C, et al. Extracorporeal Life Support Organization (ELSO) guidelines for ECMO transport; 2015. Available at: http://www.elso.org/ resources/Guidelines.aspx. Accessed October 18, 2016. 10. Trummer G, Benk C, Klemm R, et al. Short-term heart and lung support: extracorporeal membrane oxygenation and extracorporeal life support. Multimed Man Cardiothorac Surg. 2013;2013:mmt008. 11. Ganslmeier P, Philipp A, Rupprecht L, et al. Percutaneous cannulation for extracorporeal life support. Thorac Cardiovasc Surg. 2011;59:103–107. 12. Peterss S, Pfeffer C, Reichelt A, et al. Extracorporeal life support and left ventricular unloading in a non-intubated patient as bridge to heart transplantation. Int J Artif Organs. 2013;36:913–916. 13. Foley DS, Pranikoff T, Younger JG, et al. A review of 100 patients transported on extracorporeal life support. ASAIO J. 2002;48:612–619. 14. Biscotti M, Agerstrand C, Abrams D, et al. One hundred transports on extracorporeal support to an extracorporeal membrane oxygenation center. Ann Thorac Surg. 2015;100:34–39. discussion 9-40. 15. Beurtheret S, Mordant P, Paoletti X, et al. Emergency circulatory support in refractory cardiogenic shock patients in remote institutions: a pilot study (the cardiac-RESCUE program). Eur Heart J. 2013;34:112–120. 16. Thiele H, Zeymer U, Neumann FJ, et al. Intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock (IABP-SHOCK II): final 12 month results of a randomised, open-label trial. Lancet. 2013;382:1638– 1645. 17. Seyfarth M, Sibbing D, Bauer I, et al. A randomized clinical trial to evaluate the safety and efficacy of a percutaneous left ventricular assist device versus intra-aortic balloon pumping for treatment of cardiogenic shock caused by myocardial infarction. J Am Coll Cardiol. 2008;52:1584–1588. 18. Wagner K, Sangolt GK, Risnes I, et al. Transportation of critically ill patients on extracorporeal membrane oxygenation. Perfusion. 2008;23:101–106. 19. Roch A, Hraiech S, Masson E, et al. Outcome of acute respiratory distress syndrome patients treated with extracorporeal membrane oxygenation and brought to a referral center. Intensive Care Med. 2014;40:74–83. 20. Moll V, Teo EY, Grenda DS, et al. Rapid development and implementation of an ECMO Program. ASAIO J. 2016;62:354–358. 21. Broman LM, Holzgraefe B, Palmer K, et al. The Stockholm experience: interhospital transports on extracorporeal membrane oxygenation. Crit Care. 2015;19:278. 22. Coppola CP, Tyree M, Larry K, et al. A 22-year experience in global transport extracorporeal membrane oxygenation. J Pediatr Surg. 2008;43:46–52. discussion 52. 23. Aubin H, Petrov G, Dalyanoglu H, et al. A suprainstitutional network for remote extracorporeal life support: a retrospective cohort study. JACC Heart Fail. 2016;4:698–708. 24. Leick J, Liebetrau C, Szardien S, et al. Door-to-implantation time of extracorporeal life support systems predicts mortality in patients with out-of-hospital cardiac arrest. Clin Res Cardiol. 2013;102:661–669. 25. Schmidt M, Burrell A, Roberts L, et al. Predicting survival after ECMO for refractory cardiogenic shock: the survival after veno-arterial-ECMO (SAVE)-score. Eur Heart J. 2015;36:2246–2256.
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Air Medical Journal j o u r n a l h o m e p a g e : h t t p : / / w w w. a i r m e d i c a l j o u r n a l . c o m /
Original Research
Remote ECLS-Implantation and Transport for Retrieval of Cardiogenic Shock Patients Sabina P.W. Guenther, MD 1,*, Stefan Buchholz, MD 1, Frank Born, MCt, ECCP 1, Stefan Brunner, MD 2, René Schramm, MD, PhD 1, Dominik J. Hoechter, MD 3, Vera von Dossow, MD 3, Maximilian Pichlmaier, MD, MA (Cantab) 1, Christian Hagl, MD 1, Nawid Khaladj, MD, MBA 1 1 2 3
Department of Cardiac Surgery, University Hospital Munich, Ludwig-Maximilian-University, Marchioninistr. 15, 81377 Munich, Germany Medical Department I (Cardiology), University Hospital Munich, Ludwig-Maximilian-University, Marchioninistr. 15, 81377 Munich, Germany Department of Anesthesiology, University Hospital Munich, Ludwig-Maximilian-University, Marchioninistr. 15, 81377 Munich, Germany
A B S T R A C T
Objective: Extracorporeal life support (ECLS) emerges as a salvage option in therapy refractory cardiogenic shock but is limited to highly specialized tertiary care centers. Critically ill patients are often too unstable for conventional transport. Mobile ECLS programs for remote implantation and subsequent air or ground-based transport for patient retrieval could solve this dilemma and make full-spectrum advanced cardiac care available to patients in remote hospitals in whom shock otherwise might be fatal. Methods: From December 2012 to March 2016, 40 patients underwent venoarterial ECLS implantation in remote hospitals with subsequent transport to our center and were retrospectively analyzed. The mobile ECLS team was available 24/7, implantation was performed percutaneously bedside, and compact support systems designed for transport were used. Results: Twenty percent of the patients were female; the mean age was 55 ± 10 years, and the mean Interagency Registry for Mechanically Assisted Circulatory Support score was 1.3 ± 0.5. Patient retrieval was accomplished via ground-based (n = 29, 72.5%, mean distance = 27.9 ± 29.7 km [range, 5.6-107.1 km]) or air (n = 11, mean distance = 62.4 ± 27.2 km [range, 38.9-116.4 km]) transport. No ECLS-related complications occurred during transport. The ECLS system could be explanted in 65.0% (n = 26) of patients, and the 30-day survival rate was 52.5% (n = 21). Conclusion: Remote ECLS implantation and interfacility transport on ECLS are feasible and effective. Interdisciplinary teams and full-spectrum cardiac care are essential to achieve optimal outcomes. Rapidresponse ECLS networks have the potential to substantially increase the survival of cardiogenic shock patients. Copyright © 2017 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.
The achievement of maximum survival rates and the minimization of morbidity in cardiogenic shock patients frequently require the full spectrum of interdisciplinary cardiac care. In several analyses including our own preliminary results, extracorporeal life support (ECLS) was shown to provide immediate and full cardiopulmonary support with subsequent hemodynamic stabilization and a favorable outcome in critically ill patients in whom conventional therapy had failed.1-6 This therapeutic approach requires substantial infrastructure, specifically trained personnel, and suitable interdisciplinary concepts
* Address correspondence to: Sabina P.W. Guenther, MD, Department of Cardiac Surgery, Ludwig-Maximilian-University, University Hospital Munich, Marchioninistr. 15, 81377 Munich, Germany. E-mail addresses: [email protected] (S.P.W. Guenther).
and is therefore limited to specialized tertiary care centers.2 However, the transport of patients in severe cardiogenic shock imposes a substantial risk. Mobile ECLS teams offer the potential of providing the full spectrum of the latest, advanced, and high-end interdisciplinary cardiac care available to patients in remote hospitals in whom cardiogenic shock otherwise might potentially be fatal. Even though experience in ground-based retrieval exists to some extent, air transport requires compliance with specific regulations.7 Here, we describe our concept and protocol, report our initial results, and outline how to establish a suprainstitutional rapid-response ECLS program. Methods The technique of ECLS and the management strategies implemented at our center have been described previously. 1,4,8 We
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All necessary materials for the cannulation, establishment, and sustainment of ECLS during transport are compactly prepacked in a backpack, ready to use at all times, and located in a storage facility in the emergency department of our center in closest proximity to the emergency service driveway (Fig. 1). The backpack contains disinfection, sterile sheets, gowns, gloves, caps and masks, sets for arterial and venous cannulation including cannulas of different sizes, distal limb perfusion catheters, connectors, clamps, scissors, additional tubing, heparin, saline, syringes, sutures, a needle holder, and other material for sufficient fixation of cannulas and the device as well as wound dressing and protocols. Additionally, a power supply extension cable, an emergency hand drive, and an additional pump head are contained in the standard backpack. Altogether, all necessary materials including surplus and backup are taken by the mobile ECLS team, resulting in the team being self-sufficient and independent of local conditions or circumstances, even in case of unexpected incidents. Team Our mobile ECLS team consists of a cardiac surgeon specifically experienced in cannulation for ECLS and the management of ECLS including the full spectrum of intensive care and a senior perfusionist specifically trained in setting up and handling the mobile ECLS device, assisting during cannulation, and managing the extracorporeal circuit during transport. If feasible, a cardiac surgeon and/ or perfusionist in training will additionally accompany the team for educational reasons. Figure 1. The mobile ECLS system (LifeBox, Sorin Group, Munich, Germany) including the drive unit (white arrow), perfusion unit and transport mounting (black arrow) as well as the backpack (black star) and cannulas (white star).
commenced the retrieval of cardiogenic shock patients with onsite ECLS implantation and subsequent transport in December 2012 to provide support for patients in remote hospitals and thus equitable access to full-spectrum and last-resort interdisciplinary cardiac care. Support is provided 24 hours a day, 7 days per week, throughout the year. Besides substantial expertise in the placement and management of ECLS including bail-out concepts, adequate patient selection criteria, suitable protocols, and considerations on material and personnel are needed for this specific ECLS setting. Equipment and Technical Considerations Compact support systems specifically designed for transport have been developed. Requirements include small size and low weight, simplicity, easy handling, and sufficient battery capacity. The transport system used in our center (LifeBox; Sorin Group, Munich, Germany) consists of a drive unit, perfusion unit, and transport mounting (Fig. 1). The drive unit includes the drive, a control panel, and the battery. The perfusion unit consists of a centrifugal pump (Revolution 5, Sorin Group) and an oxygenator (ECCO; Eurosets, Medolla, Italy). It is phosphorylcholine coated, and the priming volume is 640 mL. The maximum revolutions per minute are 3,500/ min, and the maximum blood flow achievable is 7 L/min.7 The weight is approximately 20 kg, and the battery capacity suffices, depending on the workload, for up to 180 minutes. The pump head is licensed for 5 days of usage and is thus the limiting component. The pump is compatible with the standard stationary ECLS (Stöckert Centrifugal Pump Console, Sorin Group) and cardiopulmonary bypass systems (S5, Sorin Group) used in our department and may be switched upon arrival. Because no new circuit, pump, or kit is needed, the critical low-flow time when switching the console can be reduced to a minimum.
Means of Transport Technical requirements to be met by a suitable means of transport are adequate power supply for the extracorporeal circuit (ie, 220 V); a reliable and independent oxygen source; the ability of invasive blood pressure measurement; a suitable ventilator; and sufficient space for the emergency medical services crew, the mobile ECLS team, and the specific material and options for fast and safe (un)loading as well as for securing the equipment, ECLS circuit, and patient.9 Commonly, these are fulfilled by standard intensive care ambulances and intensive care helicopters. Additional factors to be taken into consideration include noise, climate control, adequate lighting, ceiling height, and availability of compressed air and suction.9 The overall transport time may exceed the perfusion unit’s battery capacity, and, especially in rural areas, ambulances may not be equipped with 220 V.7 For air transport, additional regulations and air worthiness criteria need to be taken into consideration as given by appropriate state, national, or international regulatory agencies, whereas for Europe those provided by the European Aviation Safety Agency apply, as described earlier.7,9 Specifically, securing the ECLS system in a helicopter needs to comply with gravitational demands (Table 1).7 For that purpose, a specifically designed mounting system is used (Fig. 2). It was secured on the base plate of the helicopter in air transport and attached to the stretcher during ground-based transport (Fig. 3).
Table 1 Extracorporeal Life Support System Mounting Devices for Usage in Helicopters Need to Comply With Specific Gravitational Demands Degrees of Freedom
Acceleration (G)
Upward Forward Sideward Downward Backward
4 16 8 20 1.5
G = gravitational constant. Modified with permission.7
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a
3
b
Figure 2. The transport mounting device: an (a) oblique front view and (b) bottom view.
a
b
Figure 3. (a) Fastening the perfusion unit onto a conventional stretcher and (b) the bottom plate of a Eurocopter 145 (Airbus Helicopters, Donauwörth, Germany) using the mounting device.
Protocol and Workflow The referring clinic contacts our department via a telephone call with immediate physician-to-physician communication available at all times. The medical history is obtained by the physician on duty, and standardized criteria are evaluated. Afterward, the case is concisely discussed with the respective attending. Patients are considered for venoarterial ECLS in case of severe refractory and conventionally intractable cardiogenic shock. In general, this definition is met in cases in which there is a requirement of increasing doses of inotropes and/or vasopressors to maintain adequate hemodynamics with evidence of end-organ hypoperfusion despite optimal care.1 In extreme cases, this implies ongoing cardiopulmonary resuscitation. Additionally, special attention is paid to the etiology and onset of cardiogenic shock, age, comorbidities, general condition, current status including catecholamine support, pH, lactate level, and secondary organ failure. In case of resuscitated patients, ischemic time, duration, and quality of cardiopulmonary resuscitation are key factors. Almost no ultimate exclusion criteria exist in these extreme situations or emergency settings, and evaluation is performed on an individual basis. In case eligibility for ECLS cannot be determined remotely or in case of doubt, the mobile ECLS team is sent out for direct evaluation on-site. The team is ready to depart within 5 to 10 minutes during working hours and a maximum of 20 to 30 minutes on call. Preparation times equal those for in-house implantation, but waiting for the means of transportation might have to be taken into consideration. Prompt departure is indispensable to ensure timely arrival and to reduce the risk of further deterioration of the patient’s condition. After the decision to send out the mobile ECLS team has been made, the physician on duty contacts the local rescue coordination center. Consequent and stringent organization and preparation are of enormous importance. Depending on the distance to the referring
hospital and the availability of landing places, time of day, weather conditions, current status of the patient, and availability, the suitable means of transportation is selected by the dispatcher in coordination with the physician on duty. Because of practical considerations, usually the same means of transport is used for both directions. In case of expected delays because of current unavailability of both intensive care ambulance and helicopter or in case of rapid deterioration of the patient’s condition (eg, ongoing cardiopulmonary resuscitation), the team may also be transported to the referring clinic using any rescue service standard car because of the compactness of the equipment. In parallel with sending out the team, recommendations for medically stabilizing the patient and instructions for preparation for ECLS establishment are given. The latter include, if not previously established, large lumen central venous catheter insertion, preferably into the internal jugular vein, and arterial catheter insertion into the right radial artery as well as providing 3 units of packed red blood cells if available. After arrival, re-evaluation on-site is performed while preparations for cannulation are parallelized in order to reduce low output und hypoperfusion time. Whenever feasible, the patient’s or relative’s consent is obtained. If no patient’s advanced directive was available, implantation was discussed and performed according to the patient’s supposed wishes in compliance with German law. Details of ECLS implantation and management have been described earlier and are adapted for remote implantation.1,5,10,11 Cannulation is feasible in intubated and ventilated patients but also in conscious patients. Percutaneous cannulation of the femoral artery and vein is performed using the Seldinger technique. This technique offers the advantage of fast cannulation, which is feasible bedside without surgical cut down.1 Imaging modalities are not mandatory. Briefly, after adequate disinfection and sterile covering of the implantation site, the femoral artery and vein are cannulated.
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ECLS request Patient evaluation
Patient considered for ECLS Sending out mobile ECLS team
Instructing referring clinic to prepare patient for ECLS establishment
Arrival in referring clinic Re-evaluation
Preparation for cannulation
Establishment of ECLS Stabilization
Air transport
Preparation for transport
Ground transport
Figure 4. The work flow for remote ECLS implantation and subsequent ground-based or air transport for the retrieval of patients in severe cardiogenic shock.
The sizes of the cannulas are selected according to the patient’s body surface area and anticipated target flow. Routinely, we used 17F arterial and 23F or 25F venous cannulas for patients with body weights above 70 kg as well as 15F arterial and 21F venous cannulas for body weights below 70 kg (Maquet Arterial HLS Cannula [MAQUET Cardiopulmonary AG, Rastatt, Germany] and Maquet Venous HLS Cannula [MAQUET Cardiopulmonary AG], respectively). Additionally, to ensure adequate distal leg perfusion and avoid lower limb ischemia, a distal limb perfusion catheter is inserted into the superficial femoral artery (Radiofocus Introducer, 6F; Terumo, Eschborn, Germany).1 After ECLS establishment, vasopressors (ie, norepinephrine and vasopressin) were reduced first according to the hemodynamic situation. To preserve left ventricular (LV) ejection and prevent ventricular distension and pulmonary congestion, inotropic support was maintained using epinephrine as the first-line therapy and milrinone or dobutamine in case of increased vascular resistance. If necessary, additional means for LV unloading were evaluated upon arrival in our center.1,12 After ECLS implantation and stabilization of the patient, preparation for transport is performed thoroughly with a special focus on securing the tubing, pump, and oxygenator as well as the transition of medication and ventilation to the ambulance’s or helicopter’s devices. Specific aspects to be considered during transport include sudden movements (vertically or horizontally) altering the patient’s or circuit’s position, cannula movement affecting the cannula entry site or positioning of the cannula’s tip, kinking, compression or entangling of the circuit, and movement or trauma of the equipment.9 The most deleterious complications during transport are accidental decannulation and circuit failure or disruption.13 Especially when moving the patient, it is 1 person’s dedicated task to manually secure cannulas and tubing. The perfusion unit can easily be attached to any standard stretcher using the specifically designed mounting device (Fig. 3), minimizing the risk of dislocation. The device is also suitable and approved for fixation in helicopters as explained previously.7 After arrival at our center, appropriate diagnostics and therapy were triaged and commenced according to the underlying pathology. In case of myocardial ischemia, the patient was transferred to the catheterization laboratory. In case the etiology of cardiogenic shock was unclear, concomitant pathologies had to be ruled out, or if cannula positioning had to be verified, whole-body computed
tomographic imaging was performed. In case of previously established diagnosis and completed diagnostics, the patient was directly transferred to the intensive care unit. Giving advanced notice of the estimated arrival time and keeping close contact to the responsible team on-site help to avoid a waiting time and ensure smooth processes. After arrival, the mobile ECLS transport system is switched to our standard stationary system (Stöckert Centrifugal Pump Console). The transport unit is immediately set up for potential retrievals to ensure constant operational readiness. A follow-up for checking the circuit and patient is performed by both the surgical ECLS team as well as a perfusionist at least once per day. A detailed work flow is depicted in Figure 4. Costs and Reimbursement In the German health care system, costs for transportation are calculated according to standardized accounting schemes. Transport to centers of a higher level of care is reimbursed via the health care insurance system. Because the helicopter is positioned at our center, no additional costs arose from the pickup of the ECLS team and material in these cases. Costs for ECLS itself are reimbursed via supplementary fees. Patients, Data Acquisition, and Statistics From December 2012 to March 2016, 40 patients underwent venoarterial ECLS implantation in remote hospitals with subsequent transport to our center and were retrospectively analyzed. Data were collected from the patients’ health care records with a special focus on documentation of transport. The duration of survival was determined from ECLS implantation date to death and at the 30-day follow-up. Retrospective data acquisition and analysis were approved by the institutional ethics committee, with individual patient’s consent being waived because of the sole retrospective design of the study. Categoric variables are presented as numbers and percentages; continuous variables are given as mean ± standard deviation. Because of the limited number of patients and the focus on infrastructure and management, only descriptive statistics are provided. Results A total of 40 patients (20.0% female, mean age 55 ± 10 years) were included. Patient retrieval was accomplished via ground-based
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Table 2 Patients’ Characteristics, Transport Details, and Outcome Variable Age (y), mean ± SD Female, n (%) INTERMACS score, mean ± SD Previous cardiopulmonary resuscitation, n (%) Ongoing cardiopulmonary resuscitation, n (%) Etiology, n (%) ACS CM Myocarditis PE Amniotic fluid embolism Prinzmetal angina Acute mitral regurgitation Dysfunction of prosthetic mitral valve Vasculitis Implantation and transport During on-call duty hours, n (%) Distance (km), mean ± SD (range) Outcome, n (%) Explantation 30-day survival
All Patients
Ground Transport
Air Transport
N = 40 55 ± 10 8 (20.0) 1.3 ± .5 28 (70.0) 7 (17.5)
n = 29 (72.5%) 56 ± 7 6 1.2 ± .4 22 4
n = 11 (27.5%) 52 ± 15 2 1.5 ± .5 6 3
22 (55.0) 6 (15.0) 3 (7.5) 3 (7.5) 1 (2.5) 1 (2.5) 2 (5.0) 1 (2.5) 1 (2.5) 23 (57.5) 37.3 ± 32.8 (5.6-116.4) 26 (65.0) 21 (52.5)
17 4 3 1 1 1 0 1 1 18 27.9 ± 29.7 (5.6-107.1) 20 16
5 2 0 2 0 0 2 0 0 5 62.4 ± 27.2 (38.9-116.4) 6 5
ACS = acute coronary syndrome; CM = cardiomyopathy; INTERMACS = Interagency Registry for Mechanically Assisted Circulatory Support; PE = pulmonary embolism; SD = standard deviation.
(n = 29, 72.5%) or air (n = 11) transport. The mean Interagency Registry for Mechanically Assisted Circulatory Support profile was 1.3 ± 0.5; predominant etiologies were acute coronary syndrome (55.0%) and decompensated cardiomyopathy (15.0%). The mean distances accomplished were 27.9 ± 29.7 km (range, 5.6-107.1 km) for groundbased transport and 62.4 ± 27.2 km (38.9-116.4 km) for air transport. In 52.5%, the referring clinic was closer than 25 km to our center; in 20.0%, it was more than 75 km away. Initially limited to hospitals cooperating with the cardiosurgical department of our center, retrieval was extended to any remote clinic after the program had become established throughout the region. With increasing experience, more air transports were performed (36.4% within the last 3 months). Seven patients (17.5%) had been on intra-aortic counterpulsation, and 3 patients (7.5%) were on Impella (Abiomed, Danvers, MA) support either at ECLS implantation or during the prior course. In all cases, hemodynamic support was insufficient to prevent further hemodynamic deterioration. In case another device was in place at the time of ECLS establishment, it was either kept for additional LV unloading or removed upon ECLS deployment or after arrival at our center, respectively. During cannulation and placement of ECLS, in 1 case malpositioning of the arterial cannula without backflow occurred. The contralateral artery was cannulated successfully. The initial cannula was removed after arrival in our center with surgical revision the following day. In 3 cases, open surgical implantation of the distal limb perfusion catheter was performed in our center because of impossible or rejected insertion on-site with subsequent ischemia and compartment syndrome in 1 patient. In 1 case of air transport, technical failure of the invasive arterial blood pressure monitoring device occurred shortly before landing and was switched to another unit right after landing. Except for this incident, no adverse events occurred during transport, and all patients were transferred to our center safely. The ECLS system could be explanted in 65.0% (n = 26) of patients, and 30-day survival was 52.5% (n = 21). Six of the survivors (6/21, 28.6%) experienced neurologic complications (2 with hypoxic brain injury, 2 with hypoxic brain injury and multiple embolic/ischemic strokes, 1 with a sub-/ epidural hematoma, and 1 with prolonged phase of awakening); 5 of them had been resuscitated. Four patients recovered with no,
mild, or moderate residual neurologic impairment. Two patients suffered severe neurologic damage with a limited prognosis. The overall survival (in-house and remote implantations) during the same time span was 42.7%. However, we recently implemented the concept of extracorporeal cardiopulmonary resuscitation, and more than one third of the in-house patients underwent implantation during ongoing cardiopulmonary resuscitation. Detailed information on patients’ characteristics and outcome is given in Table 2. Discussion ECLS has gained increasing acceptance as a rescue therapeutic option for patients in otherwise intractable cardiogenic shock.1,3,14,15 However, hemodynamic instability, end-organ dysfunction, necessity of high-dose catecholamine treatment, and other factors render the majority of these patients inconsiderable or at high risk for conventional interfacility intensive care transport to tertiary care centers providing the full spectrum of interdisciplinary cardiovascular care including ECLS.14,15 Changes in health care services because of economic considerations include progressive specification and centralization. Mobile ECLS teams with the ability of remote implantation have the potential to provide a suitable solution for this dilemma. Patients in remote hospitals in whom conventional therapy has failed and cardiogenic shock might thus be fatal via that approach can gain access to stabilization and the full spectrum of advanced heart failure management. ECLS may serve as a bridging therapy to treatment or decision, recovery, assist device implantation, and, in sporadic cases, as a bridge to transplantation.1 ECLS may exceed cardiopulmonary support capacities of other percutaneous assist systems that have been analyzed in cardiogenic shock such as intra-aortic counterpulsation (intra-aortic balloon pump), the Impella pump, or other devices.1,16,17 Earlier publications to a vast extent mainly reported on remote venovenous extracorporeal membrane oxygenation (ECMO) implantation or the retrieval of pediatric patients or comprised small numbers of patients.13,18-22 However, suprainstitutional area-wide referral programs for venoarterial ECLS have only recently emerged. With progress in technology and device safety as well as increasing experience of ECLS centers, therapeutic efforts have been expanded to those patients in remote hospitals. Compact mobile
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support systems facilitate the handling and management of the device, and percutaneous implantation techniques allow for bedside cannulation without the necessity of surgical cut down or imaging modalities.1,7 The Extracorporeal Life Support Organization provides guidelines for ECMO transport that cover all modes of extracorporeal circulation for circulatory support or oxygenation. The guidelines highlight that substantial expertise in ECMO care and interfacility transport is necessary before establishing mobile programs and providing practical considerations.9 In a large prospective proof-of-concept pilot study conducted by Beurtheret et al15 from January 2005 to December 2009 in the Greater Paris area, 87 patients were remotely placed on ECLS, 41% after cardiac arrest and 13 while being resuscitated. Seventy-five patients were successfully transferred to the tertiary care center after stabilization, and 32 survived to hospital discharge, resulting in an overall survival rate of 37%. Twelve patients (14%) were not transported because of hemodynamic instability and died within the further course. Transfer was performed within the first 24 hours in most cases; in 1 case, device dysfunction with the necessity of temporary manual assistance occurred during transport. Aubin et al23 recently reported on 115 patients who were remotely placed on ECLS (median distance to implantation site = 2.1 km, in 77% implantation under cardiopulmonary resuscitation, 44% survival to discharge) and proposed a decision tree model for triaging the patients according to survival-based predictors.23 Biscotti et al14 published their results of 100 transports (median distance = 16 miles, 3 by fixed wing aircraft) from 2008 through April 2014; however, only 19 patients had received venoarterial support, and 2 received venovenousarterial support. Initially only including highly selected patients and short distances, they extended their inclusion criteria with gaining experience. There was 1 case of accidental decannulation with a need of recannulation and 1 case of pump console failure before transport with no intratransport malfunctions.14 Throughout a time span of more than 3 years, we retrieved patients in severe refractory cardiogenic shock with remote ECLS implantation. Forty patients were transported to our center via air or ground-based transport after the establishment of ECLS. We established a formal, protocol-based system with procedural standardization and protocol refinement with gaining experience. Altogether, we experienced no ECLS-related complications during transport. As explained earlier, the means of transportation was selected according to weather conditions, availability, distance, and local circumstances. Both air and ground-based transport of patients on ECLS seem to be safe if performed by an experienced team. Detailed analyses of the impact on survival remain to be awaited. Our mobile ECLS program covers both the densely populated area of the city of Munich and the rural surroundings. Because of that, more than 50% of the referrals were from hospitals located less than 25 km away from our center. This underlines that even in densely populated regions without mobile ECLS retrieval only a limited number of patients would have access to this potentially lifesaving treatment option.15 Because of growing recognition of this therapeutic approach, the number of referring centers subsequently increased, leading to an expansion of the network over time. Raising the awareness of referring hospitals will continue to be necessary. In comparison to in-house implantation, timing in the setting of remote patient retrieval gains importance. Even in ideal settings, time to cannulation needs to be considered. In patients with out-of-hospital cardiac arrest, door to ECLS implantation time correlated with the outcome. 24 Because critical low output and hypoperfusion or even the necessity of cardiopulmonary resuscitation have to be avoided, the emergency call has to be made in a timely manner. In case no suitable intensive care ambulance or helicopter is immediately available, our team can rapidly depart via any conventional rescue service car because of the compactness of
the material and console in order to expedite arrival at the referring facility.9 With gaining experience, we performed more air transports, which may be time-saving, especially for long-distance transports. The availability of air transport does not only depend on weather conditions but also may be limited during nighttime. In our collective, the majority of remote implantations were performed during on-call duty times. Thus, remote hospitals should be encouraged to place the emergency call as soon as possible. We achieved acceptable 30-day survival and neurologic outcome rates in these severely ill patients despite the majority of the patients having been resuscitated. These results are in line with or even slightly above those of other authors.15,23 Even though complication rates are low, remote cannulation and subsequent transport are highly complex, and adverse events can be life-threatening. Difficulties experienced during cannulation likewise occur during inhouse ECLS placement and underline the necessity of experience, fundamental skills, and concepts including bail-out options. This is even more relevant for cannulation in remote hospitals because alternative options, such as surgical cut down, are limited, and because of the lack of trained staff, equipment, and diagnostic as well as therapeutic options, potential risks and consequences are magnified when leaving the familiar environment of the home institution.13 In the setting of remote cannulation, safe access and stabilization of the patient will be the main priorities, whereas advanced open surgical or interventional procedures will usually be performed after arrival at our center. Even though the exact composition of the team and the roles of each team member vary among different centers, these considerations in our opinion imply that, first, a cardiac surgeon not only being specifically trained in cannulation techniques and bail-out concepts but also in the management of patients on ECLS and, second, a perfusionist who is highly competent in handling mobile systems are indispensable as also outlined in the recommendations of the European Association For Cardio-Thoracic Surgery.2 Third, for optimal subsequent patient care, an interdisciplinary team focused on the management of cardiogenic shock and ECLS is required, and centers offering ECLS retrieval should provide the full spectrum of cardiopulmonary care including ventricular assist device implantation and transplantation programs. Provided that fundamental and dedicated expertise is ensured, remote ECLS cannulation and subsequent transport in the vast majority of the cases are safe, feasible, efficient, and effective. The implementation of area-wide ECLS retrieval programs provides an important resource for regional hospitals and offers a salvage concept for patients in therapy refractory cardiogenic shock that otherwise might be lethal. Because sufficient expertise and infrastructure as well as efficient resource use are required to operate these programs, centralization of this therapeutic concept to highly specialized centers seems to be a rational model.14 However, institutional standards as well as an adequate minimum caseload need to be defined.9 This is further underlined by caseload outcome correlations.21 Cost-benefit analyses and number needed to treat calculations are to be awaited and will be necessary to optimize processes as well as health care resource use. Similarly, scoring systems to predict in-hospital mortality while allowing for risk stratification of remote patients are difficult to establish but will be needed to further refine and optimize treatment regimens as well as inclusion criteria. Even though the survival after veno-arterialECMO score has recently been proposed by Schmidt et al,25 this score is not specifically designed for remote ECLS implantation and also did not include patients with implantation during ongoing cardiopulmonary resuscitation. Thus, for the setting of remote ECLS implantation and especially distant site patient evaluation, more specific scores are needed.23,25 Lastly, safety and quality indicators should be defined and established.
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This report has limitations inherent to any retrospective analysis limiting its power. Randomized and multicenter trials will be needed to fundamentally prove the validity of the concept of mobile ECLS programs. Long-term outcomes analyzed in large patient collectives need to be awaited. Additionally, the patients analyzed in this study represent a preselected collective because the total number of requests, of patients who died before arrival of the mobile team as well as patients who did not have an indication for ECLS implantation upon arrival have not been included in the analysis. However, the main focus of this report was methodologic. In conclusion, interfacility transport of patients on venoarterial ECLS is feasible, safe, and reliable and distinctly expands the therapeutic options for patients in severe conventionally intractable and potentially fatal cardiogenic shock in remote hospitals. A welltrained team, clear protocols, and interdisciplinary consecutive patient care are required to achieve an optimal outcome. Specifically, bail-out strategies for potential complications during both cannulation and transport need to be considered in advance. References 1. Guenther SP, Brunner S, Born F, et al. When all else fails: extracorporeal life support in therapy-refractory cardiogenic shock. Eur J Cardiothorac Surg. 2016;49:802–809. 2. Beckmann A, Benk C, Beyersdorf F, et al. Position article for the use of extracorporeal life support in adult patients. Eur J Cardiothorac Surg. 2011;40:676–680. 3. Abrams D, Combes A, Brodie D. Extracorporeal membrane oxygenation in cardiopulmonary disease in adults. J Am Coll Cardiol. 2014;63:276–2778. 4. Sattler S, Khaladj N, Zaruba MM, et al. Extracorporal life support (ECLS) in acute ischaemic cardiogenic shock. Int J Clin Pract. 2014;68:529–531. 5. Sakamoto S, Taniguchi N, Nakajima S, et al. Extracorporeal life support for cardiogenic shock or cardiac arrest due to acute coronary syndrome. Ann Thorac Surg. 2012;94:1–7. 6. Haneya A, Philipp A, Diez C, et al. A 5-year experience with cardiopulmonary resuscitation using extracorporeal life support in non-postcardiotomy patients with cardiac arrest. Resuscitation. 2012;83:1331–1337. 7. Born F, Albrecht R, Boeken U, et al. Extra corporeal life support: technical requirements and latest developments. Heart-lung-renal assistance. Z Herz Thorax Gefäßchir. 2011;25:370–378. 8. Guenther S, Theiss HD, Fischer M, et al. Percutaneous extracorporeal life support for patients in therapy refractory cardiogenic shock: initial results of an interdisciplinary team. Interact Cardiovasc Thorac Surg. 2014;18:283–291.
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9. Dirnberger D, Fiser R, Harvey C, et al. Extracorporeal Life Support Organization (ELSO) guidelines for ECMO transport; 2015. Available at: http://www.elso.org/ resources/Guidelines.aspx. Accessed October 18, 2016. 10. Trummer G, Benk C, Klemm R, et al. Short-term heart and lung support: extracorporeal membrane oxygenation and extracorporeal life support. Multimed Man Cardiothorac Surg. 2013;2013:mmt008. 11. Ganslmeier P, Philipp A, Rupprecht L, et al. Percutaneous cannulation for extracorporeal life support. Thorac Cardiovasc Surg. 2011;59:103–107. 12. Peterss S, Pfeffer C, Reichelt A, et al. Extracorporeal life support and left ventricular unloading in a non-intubated patient as bridge to heart transplantation. Int J Artif Organs. 2013;36:913–916. 13. Foley DS, Pranikoff T, Younger JG, et al. A review of 100 patients transported on extracorporeal life support. ASAIO J. 2002;48:612–619. 14. Biscotti M, Agerstrand C, Abrams D, et al. One hundred transports on extracorporeal support to an extracorporeal membrane oxygenation center. Ann Thorac Surg. 2015;100:34–39. discussion 9-40. 15. Beurtheret S, Mordant P, Paoletti X, et al. Emergency circulatory support in refractory cardiogenic shock patients in remote institutions: a pilot study (the cardiac-RESCUE program). Eur Heart J. 2013;34:112–120. 16. Thiele H, Zeymer U, Neumann FJ, et al. Intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock (IABP-SHOCK II): final 12 month results of a randomised, open-label trial. Lancet. 2013;382:1638– 1645. 17. Seyfarth M, Sibbing D, Bauer I, et al. A randomized clinical trial to evaluate the safety and efficacy of a percutaneous left ventricular assist device versus intra-aortic balloon pumping for treatment of cardiogenic shock caused by myocardial infarction. J Am Coll Cardiol. 2008;52:1584–1588. 18. Wagner K, Sangolt GK, Risnes I, et al. Transportation of critically ill patients on extracorporeal membrane oxygenation. Perfusion. 2008;23:101–106. 19. Roch A, Hraiech S, Masson E, et al. Outcome of acute respiratory distress syndrome patients treated with extracorporeal membrane oxygenation and brought to a referral center. Intensive Care Med. 2014;40:74–83. 20. Moll V, Teo EY, Grenda DS, et al. Rapid development and implementation of an ECMO Program. ASAIO J. 2016;62:354–358. 21. Broman LM, Holzgraefe B, Palmer K, et al. The Stockholm experience: interhospital transports on extracorporeal membrane oxygenation. Crit Care. 2015;19:278. 22. Coppola CP, Tyree M, Larry K, et al. A 22-year experience in global transport extracorporeal membrane oxygenation. J Pediatr Surg. 2008;43:46–52. discussion 52. 23. Aubin H, Petrov G, Dalyanoglu H, et al. A suprainstitutional network for remote extracorporeal life support: a retrospective cohort study. JACC Heart Fail. 2016;4:698–708. 24. Leick J, Liebetrau C, Szardien S, et al. Door-to-implantation time of extracorporeal life support systems predicts mortality in patients with out-of-hospital cardiac arrest. Clin Res Cardiol. 2013;102:661–669. 25. Schmidt M, Burrell A, Roberts L, et al. Predicting survival after ECMO for refractory cardiogenic shock: the survival after veno-arterial-ECMO (SAVE)-score. Eur Heart J. 2015;36:2246–2256.