Page 52 - Journal of Special Operations Medicine - Spring 2015

than Occlusion Pressure with the applier’s hands off the 3. Either a Tactical RMT or a CAT was used first ran­
tourniquet. For the Tactical RMTs, Completion Pres­ domly by paper draw (randomized block).
sure was recorded at one­click past Occlusion with the 4. The order of target Friction Pressures was also ran­
applier’s hands off the tourniquet. domized by paper draw.
5. The first tourniquet was applied to the thigh around
CAT Windlass Turns the measured and marked midpoint, with the fric­
The first 90° rotation of the windlass placed the wind­ tion buckle on the lateral aspect of the thigh with
lass parallel to the strap and was counted as zero turns. the strap pulled downward to tighten.
Each 180° windlass rotation thereafter was counted as 6. The strap was tightened as close as possible to the
one turn. target Friction Pressure, generally within 5mmHg.
7. The actual Friction Pressure was recorded.
Tactical RMT Ladder Distance 8. The mechanical advantage system was engaged to
The distance from the rivet­secured end of the ladder to reach Occlusion and Completion with Occlusion
the ratcheting buckle in the fully released, starting posi­ Pressures and Completion Pressures recorded.
tion was measured for each Tactical RMT. The distance 9. At Completion, the number of windlass 180° turns
from the rivet­secured end of the ladder to the ratchet­ was recorded for the CATs, or the length of the lad­
ing buckle was measured at Completion. The difference der not pulled through the ratcheting buckle was
between the Completion value and the starting position recorded for the Tactical RMTs.
value was calculated as the Tactical RMT ladder dis­ 10. The distance involved in any strap bunching was
tance used. marked and measured.
11. Recipients rated discomfort as None, Little, Moder­
Bunching Index ate, or Severe.
At Completion, tape pieces were secured to the tour­ 12. The tourniquet was released but not removed.
niquet strap on both boundaries of any bunching. The 13. The length of the strap that had exhibited bunching
Completion bunched distance between the tape pieces was measured with the tourniquet released.
was measured, and the tourniquet was released. The re­ 14. Any application or release comments were recorded.
leased unbunched distance between the tape pieces on 15. The tourniquet was tightened as close as possible
the tourniquet was measured. The Bunching Index was to the next target Friction Pressure, and steps 7
calculated by dividing the released unbunched distance through 15 were repeated until all of the applica­
by the Completion bunched distance. Nonmeasureable tions of the tourniquet were finished.
bunching was assigned a Bunching Index of 1. 16. After a variable time period, steps 4 through 15
were undertaken with the second tourniquet.
Subjects
Tourniquet recipients were volunteers. Inclusion criteria Statistical Analysis
®
for recipients were involvement in the planning of this Numeric pressure data were organized in Microsoft
study or involvement to the extent of authorship in a Office Excel 2003 (Microsoft Corp., www.microsoft.
prior tourniquet study. Exclusion criteria for recipients com). Using data from each recipient, Pearson correla­
were self­reported blood clotting or circulation irregu­ tion coefficients were calculated separately for Friction
larities, implants in relevant locations, systolic blood Pressure versus Occlusion Pressure. Separate coefficients
pressure >140mmHg, pain syndromes, or peripheral were also calculated for Friction Pressure and Occlusion
neuropathies. Pressure versus Bunching Index or ladder distance or
windlass turns. Using the entire dataset, Pearson cor­
The authors were the tourniquet appliers, with one relation coefficients were calculated for Strap versus
author doing most of the applications and actively in­ Ladder or Base for Friction Pressures and for Occlusion
volved in every data collection session. All of the ap­ Pressures. Two­way analysis of variance (ANOVA) was
pliers practiced with both CATs and RMTs under the used to assess the significance of differences between
supervision of the author with the most tourniquet ex­ Tactical RMT and CAT Occlusion Pressures (Tactical
perience. Applications sometimes involved two appliers RMT Strap versus CAT Strap or Tactical RMT Ladder
to reach the target Friction Pressures. versus CAT Base). Two­way ANOVA was also used to
assess Strap and Ladder or Base Occlusion Pressures
Protocol (Tactical RMT Strap versus Tactical RMT Ladder or
1. All tourniquets were applied directly on skin at the CAT Strap versus CAT Base). A chi­square test was used
midpoint of one thigh, with the same thigh used for for discomfort ratings. Graphing and statistical analy­
both tourniquets. ses were performed using GraphPad Prism version 5.02
2. Recipient systolic blood pressure and thigh circum­ for Windows (GraphPad Software Inc., www.graphpad
ference at the midpoint were recorded. .com). Medians are shown with ranges. Averages are

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