The COVID-19 pandemic shows different outbreak patterns within countries.1,2 Although some areas are heavily affected, and their medical capacities are overburdened, other regions are less affected. The outbreak in Germany shows multiple cluster formations. Many of these hotspots are located in Bavaria in southern Germany (Figure 1). Since the city and district of Regensburg were not heavily affected, we were able to offer treatment for COVID-19 patients from other districts, including venovenous extracorporeal membrane oxygenation (VV-ECMO) for severe acute respiratory failure. This article describes our experience in out-of-center VV-ECMO implantation including interhospital transfer to our center.
We retrospectively extracted data from records of all consecutive COVID-19 patients receiving out-of-center VV-ECMO at different retrieval hospitals and consecutive interhospital transfer to our ECMO-center in March and April of 2020.
We collected available data on demographic, medical, and transport characteristics of the patients. We compared respiratory, circulatory, and blood gas parameters before and after VV-ECMO initiation. Also, we compared transport characteristics of COVID-19 patients to seven non-COVID-19 patients, who received out-of-center VV-ECMO because of lung failure in January and February of 2020 and were transported by helicopter. For the comparison, we used a two-tailed paired t-test with α = 0.05. Data were analyzed using IBM SPSS Statistics 25 (IBM). The study was approved by the ethical committee of the University of Regensburg.
We treated 10 patients with COVID-19 associated lung failure using VV-ECMO with out-of-center initiation. In all COVID-19 patients, single-lumen cannulae were used via the femoral-jugular approach (Maquet cannulae, outflow 38 cm, 21/23 Fr., inflow 15 cm, 17–21 Fr.). We mostly used either the Cardiohelp system (combined pump/oxygenator) or the combination of a Deltastream DP3 pump with a Hilite LT oxygenator. The interhospital transfer was successful in all cases with no adverse events. Patient characteristics of the COVID-19 and the non-COVID-19 patients (comparison group) are presented in Table 1, along with the parameters of the non-COVID-19 patients. Depending on the distance between the retrieval hospitals and our center, weather conditions, and availability of rescue services, either ground (ambulance) or air transport (helicopter) was used for ECMO-team and patient transport in the COVID-19 group. Four times team transfer to retrieval hospitals and patient transport were conducted via ground transport, four times via air transport, and twice the team was transported by air, and the patient then returned via ground. Comparison of on-scene times showed a statistically significant difference between COVID-19 and non-COVID-19 patients with a mean of 99 (SD = 11) versus 65 minutes (SD = 14) (p < 0.001; data only available for six patients in the COVID-19 group). For COVID-19 patients with subsequent airborne transfer, the time from handover at our center until the helicopter was ready for use again was longer in the COVID-19 group with 60 (SD = 23) versus 35 minutes (SD = 11) in the non-COVID-19 group (p = 0.046). Time to cannulation was 47 (SD = 23) versus 38 minutes (SD = 12), respectively (p = 0.368). We only analyzed these times since all other times (e.g., total time) would be confounded by the different distances to the retrieval hospitals. The ECMO-team consisted of three people (perfusionist, paramedic/intensive-care nurse, emergency physician). Implantation was performed according to center standards, being described in previous publications.3 Although the perfusionist cared for all 10 COVID-19 patients, the nurse/paramedic, and the emergency physician changed depending on the duty roster. A total of 10 people were involved in direct patient care. None of these people showed any signs of an infection with Sars-CoV-2 up to the date of submission of this manuscript. All of them were equipped with full personal protective equipment (PPE) during the initiation of VV-ECMO and transfer of the patients (including goggles, N99-masks, double gloves, and gowns). People not involved in direct patient care (pilots, ambulance personnel) wore surgical masks.
Table 1. -
||Covid-19 Patients (n = 10)
||Non-Covid-19 Patients (n = 7)
||Comparison of Covid-19 and non-Covid-19 Patients (p)
| Age, y
| Male gender, n (%)
| BMI, kg/m2
||At Initiation of VV-ECMO (Covid-19)
||2 h After Initiation of VV-ECMO (Covid-19)
||Comparison Before and After VV-ECMO (p)
||At Initiation of VV-ECMO (Non-Covid-19)
||Comparison of Covid-19 and non-Covid-19 Patients Before VV-ECMO (p)
|Plateau airway pressure, cmH2O
|Minute ventilation, L/min
|Respiratory rate, breaths/min
|Norepinephrine dose, µg/min/kg
Data presented as means (SD), unless otherwise indicated.
BMI, body mass index; PEEP, positive end-expiratory pressure; VV-ECMO, venovenous extracorporeal membrane oxygenation.
VV-ECMO has been established as a therapeutic option in acute lung failure worldwide, while its superiority over conventional mechanical ventilation has yet to be proven.4 Its role in the treatment of COVID-19 is also up to debate, while it is clear that VV-ECMO cannot be a frontline treatment in a pandemic situation where health systems are overwhelmed by the number of patients.5
Our data show that out-of-center cannulation and consecutive interhospital transfer of these patients can be safely and successfully achieved. The COVID-19 patients in this study were predominantly male and overweight, two factors that have been identified to be risk factors for more severe disease trajectories.6,7 VV-ECMO in our patients led to fast stabilization of ventilation parameters, and a reduction of the invasiveness of ventilation could be reached, enabling safe interhospital transfer. The transfer itself showed to be complex and time-consuming. Although the time for cannulation was not significantly longer than usual, the general measures took more time (e.g., donning and doffing PPE, disconnecting and reconnecting the ventilator, meticulous disinfection of the helicopter). Working under full PPE for a longer period and maintaining the protection during patient transfer proved to be extremely strenuous but still possible. We concur with the current guidelines by the Extracorporeal Life Support Organization8 to keep the number of people involved in patient care as low as possible to reduce the risk of infection. In our experience, three experienced team members were sufficient to perform safe cannulation and transfer, knowing that other centers use bigger teams.9 Our study did not evaluate whether VV-ECMO is a valuable asset in the therapy of COVID-19 patients. This has to be determined in more extensive outcome studies.
In summary, out-of-center VV-ECMO initiation and consecutive transfer for COVID-19 patients is possible when resources are still available. Due to its complex nature, initiation and especially transfer should be carried out by experienced teams.
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