Page 52 - Journal of Special Operations Medicine - Winter 2014

use. These limitations include difficulty placing them at Our study compared the efficacy of CG with NS in
the exact site of a hemorrhage and reactions that can controlling arterial hemorrhage in a well-published and
potentially cause tissue damage. Because of the issues validated porcine traumatic femoral wound model.
identified with using QuikClot, HemCon Bandage, and
ChitoFlex, the current hemostatic agent of choice in com-
bat, as recommended by the Defense Health Board Com- Methods
mittee on Tactical Combat Casualty Care (CoTCCC), is
Combat Gauze (CG). 8–10 Study Design
This study was a randomized, controlled, unblinded
CG is a thin, flexible, nonwoven rayon–polyester blended preclinical trial using a swine model of acute femoral
(50% rayon and 50% polyester) gauze impregnated with hemorrhage. Two intervention groups of eight animals
mineral kaolin powder (Figure 1). Kaolin is a naturally and seven animals were examined using two different
occurring, inorganic mineral that does not contain any hemostatic agents, NS and CG, respectively. Standard
botanicals, biologic material, or shellfish products, and dosages and techniques, as recommended by the man-
has not been shown to produce an exothermic reaction ufacturer, were used. Prior to the study, the individual
or cause vascular complications. 8,9,11 applying the dressing (applicator) had previously done
so with each dressing more than 50 times. NS was pro-
vided directly from the manufacturer and CG was pur-
chased from Boundtree Medical (www.boundtree.com).
Figure 1 Combat Gauze The protocol was approved by the Institutional Animal
is an impregnated rayon– Care and Use Committee. All research was conducted in
polyester blend dressing
currently used by civilian compliance with the Animal Welfare Act. The animals
emergency medical service received humane care in accordance with the “Guide for
and battlefield medical the Care and Use of Laboratory Animals.” 15
personnel.
Animal Subjects
The study was conducted in the controlled environment
of a veterinary surgical suite designed to accommodate up
to two subjects at any one time. Farm-raised, Yorkshire
NuStat (NS) (Beeken Biomedical; http://www.beeken swine (Sus scrofa, Blackwater Farms, Franklin, VA, USA)
®
biomedical.com/nustat.html) is a novel hemostatic dress- were chosen as study subjects. This choice was made
ing with a unique combination of two fibers: silica-based due to the reliability of swine as a cardiovascular model
fibers and regenerated cellulose (Figure 2). NS contains and the ease of accessibility. Subjects were randomized
no pharmaceutical or biologic agents. The mechanisms and required to be within age and weight ranges per the
underlying NS’s hemostatic properties encompass both protocol.
cellular and molecular interactions, including platelet
activation and amplification of the intrinsic coagulation Study Protocol
cascade through activation of factor XII. The silica- and The 15 swine were fed a standard diet and observed for a
12
cellulose-based fibers enhance platelet recruitment to the minimum of 5 days. Animals were fasted the night prior
wound site via surface-charge–mediated interactions and to the procedure and water was provided ad libitum. An-
amplify the activation and aggregation of platelets. The esthesia was induced with an intramuscular injection of
dressing also triggers the coagulation cascade by ampli- ketamine (20mg/kg) and 5% inhaled isoflurane via face
fication of protein–enzyme reactions in the blood and mask for 3 minutes. Maintenance anesthesia was set at
accelerates the formation of platelet–fibrin networks. 13,14 2% isoflurane after endotracheal intubation, and the an-
imal remained breathing spontaneously on 21% oxygen
and air administered from an MDS Matrx VMC small-
Figure 2 NuStat is animal anesthesia machine (Matrx Medical; www.henry
a knit dressing of schein.com/us-en/Matrx/default.aspx) for the duration
regenerated cellulose of the procedure. The animal was placed supine on the
and silica currently
used for emergency operating table with the front legs secured to allow ad-
medical service, equate access to the neck. The right carotid artery and
burn, and trauma external jugular vein were then exposed via a cutdown
applications by medical, technique. A 22-gauge catheter was used to cannulate
law enforcement, and the carotid artery for continuous arterial blood pressure
civilian personnel. monitoring. The external jugular vein was cannulated

42 Journal of Special Operations Medicine Volume 14, Edition 4/Winter 2014