Page 34 - Journal of Special Operations Medicine - Winter 2016

Table 1 Completion-Pressures, Friction-Pressures, Mechanical Advantage System Use
Tourniquet Application:
Target Completion-Pressure, Completion-Pressures Friction-Pressures Number of Windlass Turns
Gel or Limb, Tourniquet (mmHg) (mmHg) or Ratchet Teeth Advances
262mmHg
10% ballistic gel
C-A-T 268, 265, 258 151, 158, 151 1,1,1
RMT 261 125 18
Blood pressure cuff 268, 269, 274 NA NA
SWATT 263, 260, 263 NA NA
20% ballistic gel
C-A-T 274, 264, 259 88, 85, 97 1,1,1
RMT 258, 275, 260 126, 176, 162 9, 7, 7
Blood pressure cuff 276, 262, 254 NA NA
SWATT 276, 269, 265 NA NA
Human thigh
C-A-T 272, 250, 287 100, 105, 108 1, 1, 1
RMT 253, 251, 263 82, 96, 96 8, 8, 9
Blood pressure cuff 271, 279, 276 NA NA
SWATT 248, 268, 283 NA NA
Human arm
C-A-T 259, 253, 275 85, 84, 131 1, 1, 1
RMT 297, 250, 279 110, 95, 103 7, 5, 5
SWATT 255, 251, 262 NA NA
362mmHg
10% ballistic gel
C-A-T 350, 368, 347 191, 218, 195 3, 3, 3
Blood pressure cuff 368, 369, 366 NA NA
SWATT 387, 347, 357 NA NA
20% ballistic gel
C-A-T 361, 373, 355 172, 170, 156 2, 2, 2
RMT 356, 355, 354 175, 181, 193 15, 12, 12
Blood pressure cuff 362, 365, 361 NA NA
SWATT 367, 369, 361 NA NA
Human thigh
C-A-T 413, 352, 402 151, 148, 157 1, 1, 1
RMT 328, 352, 345 80, 87, 87 11, 10, 11
Blood pressure cuff 366, 371, 370 NA NA
SWATT 330, 365, 353 NA NA
Human arm
C-A-T 340, 335, 334 82, 84, 82 1, 1, 1
RMT 418, 353, 409 121, 119, 119 6, 6, 6
C-A-T, Combat Application Tourniquet; RMT, Ratcheting Medical Tourniquet; NA, not applicable; SWATT, Stretch Wrap And Tuck-Tourniquet.

In thigh C-A-T and RMT applications, higher comple- Similar to thigh applications, arm application pressure-
tion-pressures resulted in faster pressure losses and more loss curves (Figure 1D and Figure 2D) involved faster
negative plateaus than occurred at lower completion- pressure losses and greater plateaus with the higher
pressures. Despite greater losses at the higher comple- completion-pressures than the lower completion-pres-
tion-pressures, the final tourniquet pressures at infinity sures. The pressure-loss curves of the smaller circumfer-
would still be higher than with the lower completion- ence arm applications frequently involved more pressure
pressures. To restate, the higher completion-pressure loss than thigh applications.
plateau pressures were not 100mmHg greater than the
lower completion-pressure plateau pressures. Size and Shape Changes
Size and shape changes occurred during tourniquet
The lower completion-pressure C-A-T and RMT thigh tightening to application-completion: the portion of
applications had pulsatile pressure decay traces as a ballistic gels and thigh directly under each tourniquet
consequence of not maintaining occlusion. The pressure became smaller in diameter (Figures 3 and 4). Visible
pulsations are not well shown with graphed data points changes did not occur during the 300 or 600 seconds
at 30 second intervals (Figure 1C). after application-completion. Upon tourniquet removal,

18 Journal of Special Operations Medicine Volume 16, Edition 4/Winter 2016