Page 80 - 2020 JSOM Winter

While venoarterial (V-A) ECMO is increasingly being used in FIGURE 1 Experimental protocol.
the setting of cardiogenic shock and CA (E-CPR) at select civil-
ian centers, the utility of artificial circulation for hemorrhagic
shock and TCA remains a matter of active investigation. Re-
cent experience from leading trauma centers has demonstrated
success in the effective use of V-A ECMO for saving severely
polytraumatized patients by appropriately trained and config-
ured teams. 10,14 To date, however, no examination of the fea-
sibility of this intervention in an austere military environment
has been reported.
Our present report outlines the results of a feasibility study
conducted in the context of military exercise setting. A sce-
nario of out-of-hospital/battlefield TCA, followed by combat
casualty care and staged forward resuscitative care, was de-
signed to simulate circumstances in which E-CPR might be
potentially employed during military conflict.

Methods
Overview
This study was performed during the May 2018 and June
2019 iterations of the annual military medical exercises held at
the educational center of the Kirov Military Medical Academy,
Saint Petersburg, Russian Federation. For the purpose of train-
ing and investigation, we generated a specific experimental CA
four-stage protocol consisting of animal preparation, induc-
tion of CA, resuscitation including ECMO initiation, and tac-
tical evacuation on ECMO (Figure 1). All animal live-tissue
training and investigations during the military exercises are ECMO = extracorporeal membrane oxygenation; IV = intravenous;
V-A = venoarterial.
conducted under annual protocols reviewed and approved by
the local ethical committee. This study, spanning a 2-year pe-
riod, was approved by the ethical committee of the Kirov Mil- FIGURE 2 The animal admitted to a Role 1 medical treatment
itary Medical Academy (protocol No. 203, 20 March 2018). facility on ongoing cardiopulmonary resuscitation. Surgical
cricothyrotomy is performed, and femoral vessels are explored for
subsequent cannulation.
Experimental Protocol
Animal preparation
Sus scrofa (wild swine) study subjects weighing 40kg each
were housed in quarantine at the animal facility for 14 days.
After initial sedation with 400mg tiletamine and zolazepam
(Zoletil; Virbac, France), an ear vein was cannulated for pri-
mary drug administration, and the left carotid artery was ex-
posed for placement of a 6-Fr retrograde sheath. This sheath
was then used to facilitate a controlled hemorrhage, blood
pressure monitoring, and blood sampling. The animal was
then placed on an outdoor litter close to a simulated Role 1
MTF, consisting of a field tent facility with an operating table,
a ventilator, and a basic kit of surgical instruments.

Induction of CA
We chose a combined (hemorrhage-induced plus nontrau-
matic) mechanism of CA for our study protocol. After con-
trolled removal of 35% of total blood volume (stored using
1000IU of heparin per unit), 20mg/kg potassium chloride Along with surgical cricothyroidotomy, 50IU/kg heparin was
was administered. We then used ultrasound (Sonoscape S6, administered and emergency cannulation was performed.
China) and electrocardiography to document loss of heart Both the femoral artery and vein were exposed and instru-
contractility. mented with 12-Fr 7.5–9" and 17- to 18-Fr short (12") or
long (30") cannulae, respectively, for emergent V-A ECMO–
CPR and ECMO Protocol E-CPR. Cannulae were reliably secured to the body and con-
One minute after documented CA, a Lucas2 chest compression nected to a perfusion device. Pump flow was initiated at blood
system (Jolife, Sweden) was applied over the animal’s chest flow rate (BFR) of 600mL/min and increased slowly to 1500
for ongoing CPR. During CPR, the animal was transported to 2500mL/min. As early as 10 minutes after the ECMO pro-
to a tent (Role 1) and placed on a surgical table (Figure 2). cedure was initated, the animals were resuscitated with whole

78 | JSOM Volume 20, Edition 4 / Winter 2020