Page 68 - Journal of Special Operations Medicine - Spring 2015

hemorrhage with aggressive fluid resuscitation and, sub­ Heart rate, electrocardiography, blood pressure, oxy­
sequently, movement. Gegel and colleagues compared gen saturation, end­tidal carbon dioxide level, and rec­
15
the effectiveness of QCG to that of a control treat­ tal temperatures were continuously monitored for the
ment in a group of normothermic swine. They found remainder of the experiment. The left carotid artery
28
the agent was effective in controlling hemorrhage, and was cannulated with a 20­gauge angiocatheter using a
the clot formed was robust enough to withstand more cut­down technique. It was attached to a hemodynamic
movement than the control. In another study, the same monitoring system (Hewlett Packard, Palo Alto, CA,
28
researchers investigated the effectiveness of QCG in a USA; http://www.hpl.hp.com) for continuous monitor­
hypothermic scenario. They found QCG was superior ing of the arterial blood pressures. A central venous
to the control treatment relative to hemorrhage control, catheter was inserted in the subclavian vein using the
fluid resuscitation, and movement. No study has com­ modified Seldinger technique. The activated clotting
13
pared the effectiveness of QCG in a hypothermic, hemo­ time (ACT) test was used to screen all subjects for pre­
diluted model with movement. existing coagulopathy. Subjects were further monitored
for 30 minutes to ensure hemodynamic stability. Tem­
The purpose of this study was to compare the effective­ perature was monitored via rectal probe. All swine were
ness QCG to a control group relative to movements. hemodynamically stable prior to intervention.
Specifically, this study was guided by the following re­
search question: Is there a significant difference between Thirty percent of each animal’s blood volume was ex­
QCG and control groups in number of movements in a sanguinated by gravity by a central line into the sub­
porcine model of hemodilution and hypothermia before clavian vein. Swine have the same volume of blood as
hemorrhage occurs? humans (70mL/kg); therefore, a pig that weighs 70kg
has 4900mL of blood. Thirty percent of that volume is
1470mL. A 3:1 replacement of lactated Ringer’s solu­
Methods
tion was administered to dilute the remaining blood.
This was a prospective study with a between­subjects
experimental design using a porcine model. The proto­ Hypothermia (<34.0ºC) was induced by three methods:
col was approved by the Institutional Animal Care and cooling blanket, ice packs, and cold isopropyl alcohol
Use Committee and the animals received care in compli­ spray. Once the temperature reached ≤34ºC, the inves­
ance with the Animal Welfare Act and the “Guide for tigators created a complex groin injury to simulate a
the Use of Laboratory Animals.” penetrating inguinal wound. Following the 30­minute
stabilization period and 10 minutes of hypothermia, a
The investigators calculated a large effect size of 0.6 complex groin injury was created (transection of femo­
based on the previous work from Gegel and Johnson. 15,28 ral artery and vein). A complex groin injury was cre­
30
Using an effect size of 0.6, a power of 0.80, and an α ated to simulate a penetrating, traumatic battlefield
of .05, the researchers determined that 26 swine were injury. Specifically, the proximal thigh soft tissues (skin,
needed for the study. The investigators used a computer­ quadriceps, and adductor muscles) were dissected to ex­
based randomized­number generator to assign York­ pose the femoral artery and vein below the inguinal liga­
shire swine to either the QCG group (n = 13) or the ment within the femoral crease.
control group (n = 13). The mean weight of the swine
was 71.3kg (the mean plus or minus the standard devia­ The femoral artery and vein were transected, and the
tion [SD] was 70.19 ± 8.94kg in the QCG group and swine were allowed to bleed for 1 minute, simulating
72.57 ± 11.9kg in the control group), which represents the response time of a battlefield healthcare provider.
the average weight of the US Army Soldier. 29 Blood was collected through the use of 4" × 4" gauze,
absorbent pads placed underneath the animals, and by
Swine were administered a preoperative intramuscular suction­tip catheter placed in the distal portion of the
injection of ketamine (20mg/kg) and atropine (0.04mg/ wound per manufacturer’s guidelines. After 1 minute
kg). Subjects were placed supine on a litter and admin­ of uncontrolled hemorrhage, proximal pressure was
istered inhaled isoflurane (4% to 5%). After placement applied to the transected femoral vessels, and 4" × 4"
of an endotracheal tube, a peripheral intravenous (IV) gauze was used to blot the blood from the wound per
catheter was inserted and the isoflurane concentration the hemostatic agent manufacturer’s guidelines. QCG
was reduced to between 1% and 2% for the remain­ was packed into the wound, making direct contact
der of the experiment. The subjects were ventilated with the transected vessels. An overlying layer of petro­
with a standard Narkomed anesthesia machine (Dräger, leum gauze was applied to prevent adhesion of QCG
Telford, PA, USA; http://www.dremed.com/em_drager_ to wound packing materials, allowing for later dressing
narkomed.shtml). removal. Standard wound packing, using roller gauze

58 Journal of Special Operations Medicine Volume 15, Edition 1/Spring 2015