Page 57 - JSOM Fall 2019

FIGURE 2 Optimal thigh Tactical RMT app lication. FIGURE 3 Optimal thigh SWATT application.

(A) (B) (A) (B)

(C) (D) (C) (D)

(A) The applier should hold the built-in tactical loop and pull the strap (A) The first wrap of the SWATT has minimal stretch. The next wrap
as tight as possible through the properly threaded slip-lock rings of overlaps approximately one-quarter of the first wrap to secure the
the self-securing redirect buckle. The direction of strap pull should be tourniquet on the limb and is then stretched to at least 200% of the
parallel to the portion of the strap encircling the thigh before enter- original material length so that the printed on symbols become appro-
ing the redirect buckle (0° angle). Optimal strap-pulling technique priately shaped (diamonds in oblongs become squares in circles and
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uses the applier’s body weight to advantage. (B) An optimal strap rectangles become squares). (B) SWATT stretch is maintained through-
pull will result in visible tissue indentation and should ideally have out the entirety of each ensuing wrap. Arterial occlusion is already
a secured strap pressure ≥150mmHg (140mmHg for the shown strap present in this picture (start of the fourth wrap). (C) Each wrap should
application). Self-securing redirect buckles have more friction than be flat and should completely overlap the underlying wrap. Never give
non–self-securing redirect buckles, so achieving pressures ≥150mmHg up any stretch. Arterial occlusion is already present in this picture
can be challenging; however, with the slip-lock rings of the Tactical (halfway through the fourth wrap). (D) This is a completed arterially
RMT, most appliers should be able to achieve a strap pressure of occlusive SWATT application with a pressure of 471mmHg, which is
≥100mmHg. The tubing seen just distal to the knee is part of the pres- 274mmHg beyond the pressure at which occlusion occurred. Across
sure-measuring system. (C) The ratcheting buckle should be advanced 29 adult 39cm to 56cm circumference thigh applications, the mean
with downward pressure directing the advancing pawl into the teeth ± standard deviation pressure required to achieve arterial occlusion
of the ladder. With an optimal strap pull, only five or six ratchet clicks was 233 ± 55mmHg (95th percentile of 336mmHg). Good SWATT
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(single tooth advances) will be required to achieve arterial occlusion. completion requires preplanning because, at the start of the last wrap,
Because significant pressure loss occurs over time under nonelastic the applier should create and hold a space into which the free end of
tourniquets, advancing the ratcheting buckle at least one click be- the last wrap will be tucked to complete the application. The amount
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yond arterial occlusion is recommended. (D) This is an arterially occlu- of SWATT tucked into the space should not be minimal. Arterially oc-
sive application with the ratcheting buckle advanced one click beyond clusive thigh applications of the 10.4cm-wide SWATT will have visible
arterial occlusion and a completed pressure of 301mmHg. Across 420 tissue indentation.
adult 34.5cm to 72.7cm circumference thigh applications, the mean ±
standard deviation pressure required to achieve arterial occlusion was
334 ± 56mmHg (95th percentile of 428mmHg). 24,60–63 Arterially occlu- double-routing in two-handed CAT applications, the report
sive thigh applications of 3.8cm-wide, nonelastic tourniquets such as documented 70% leg injuries but only 62% of C-A-Ts dou-
the Tactical RMT will have visible tissue indentation. ble-routed. This suggests 8% of C-A-Ts used on leg injuries
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were single-routed rather than double-routed.
Nonoptimal Tourniquet Applications In the ideal setting of laboratory use, results from various
Table 1 lists sources with tourniquet application problems. It studies by Wall et al. 61,64 show appliers given only the subjec-
should be kept in mind that not all things we know now about tive goal of pulling a tourniquet strap “as tight as possible”
tourniquet application were known throughout the entire pe- often do not achieve desirable secured strap tightness before
riod during which the identified studies were done. use of the mechanical advantage tightening system. Of 48 two-
handed, double-routed C-A-T applications, 32 had prewind-
People Need Performance Feedback lass engagement strap pressures <100mmHg (67%) and only
with Prioritized Goals two had prewindlass engagement strap pressures >150mmHg
Data from military and laboratory use show variable applier (4%). Of 96 two-handed 3.8cm-wide RMT applications, 68
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success following instructions. Despite training and C-A-T had preratchet engagement strap pressures <100mmHg (71%)
printed instructions, the 2011 publication by Kragh et al. con- and only eight had preratchet engagement strap pressures
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cerning military tourniquet use stated, “most appliers in train- >150mmHg (8%). 61
ing and care actually put the band in the one-handed routing
inadvertently even when doing the two-handed application With access to real-time strap pressure data and an objective
unless specifically forewarned.” This is supported by Kragh strap-pressure goal, appliers do better, and prioritizing the ob-
et al.’s 2013 publication involving 293 recovered C-A-T tour- jective strap pressure goal is important. With four appliers,
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niquets from military casualty use. Despite instructions to use real-time strap-pressure monitoring during RMT applications,

Getting Tourniquets Right | 55