Current situation:
Currently, 11 Dutch ECMO centers provide ECPR in the Emergency Room (ER), Cathetherisation Laboratory or Operation Theratre. Patients with refractory out-of-Hospital cardiac arrest (OHCA) generally arrive, with ongoing resuscitation, on the ER approxmately 50 min after initial call to the emergency services. If the team decides to perform ECPR, ECMO bloodflow generally starts after approximately 70 min of ongoing CPR. In the Erasmus University Medical Center Rotterdam, ECPR leads to a survival to hospital discharge of 29%.
One of the key factors to consider a patient for ECPR is that time between initial emergency call and arrival to the ER is shorter than 60 min. This means that collapse should be relative near an ECMO center. In the figure hereunder, are the 11 Dutch ECMO centers depicted. An indicative circle is drawn around an ECMO center as place where collaps should take place, in order to arrive within 60 min after emergency call to the ER in one of the Dutch ECMO centers. It shows that in a little more that 50% of the Dutch area, no ECPR can be provided in eligible OHCA patients.
Situation from 2022 on:
Prehospital ECPR provided by the Helicopter Emergency Medical Services can deliver fast prehospital ECPR and covers a great area. Nowadays, the Netherlands have 4 HEMS stations, which cover the entire country, having annually approx 13.000 calls. A HEMS team is 24/7 present at the HEMS station and fly according to Visual Flight Rules (VFR) day and night. A HEMS team consists of 3 persons: a HEMS pilot, a HEMS nurse and a board certified anesthesiologist or trauma surgeon. If weather conditions do not allow flight under VFR, a ground bounded transport is immediately available. After dispatch, the helicopter is airborn after 2 min in daytime and 4 min in night time.
A wet-primed ECMO is placed 24/7 in the helicopter and in the HEMS emergency vehicle. In the left figure, the 4 HEMS stations are depicted. Time zones are defined in which the HEMS team can land within 20 min after dispatch.
From 2022, the HEMS teams are immediately dispatched on every OHCA of patients assumed to be 50 years or younger. If paramedics arrive before the HEMS team and the primary rhythm is an asystoly or the time of last seen well is more than 5 min, the HEMS team can be cancelled.
After arrival of the HEMS team, assuming a cannulation time of 15 min, ECMO bloodflow can start after approximately 35 min after initial dispatch.
Providing HEMS teams with ECMO for prehospital ECPR have 2 potential major benefits, which still has to be proven in daily practice.
1) Reducing low-flow time (time under CPR) from approx. 70 minutes to approx. 35 min.
2) Making ECPR available for the entire country, avoiding geographical differences in resuscitation care.
Limitations
A major limitation of this approach is that it is build on existing strcutures of care. The current HEMS teams already have a dispatch occurence of approx 13.000 times annually, with a mean occupency rate of approx 25%. Although an occuppancy of 25% doesn’t seem high, an high redundancy rate is nessesary to provide specialized care. By limiting eligible patients for prehospital ECPR to the age of 50 years or younger, we expect to include 200 patients each year (1,5% increase in total patient load).