Page 47 - JSOM Fall 2020

A clinician-scientist experienced with tourniquet and conver- Independent of clinical simulation, wraps were additionally
sion procedures performed the tests and collected data as the assessed for their inflated pressure on the manikin. Pressures
investigator. The investigator simulated an emergency health- during 6-hour use were measured to see if the wrap’s bladder
care provider who was uninjured, undistracted, at arm’s length held its air well. Measurements were made at 0, 1, and 10
to the patient, and had all materials at hand. Before beginning minutes and 1, 2, 4, and 6 hours. Each model (4-in. and 6-in.)
tests, the investigator donned gloves. had one device assessed.

The hemostatic dressings had been intended for other ex- Descriptive statistics were used to report results. Analyses were
periments but had expired. Information on dressings, tour- performed using Excel 2003 (Microsoft, www.microsoft.com).
niquets, and bandage rolls is listed in Table 1. We reclaimed
and repurposed these packaged gauzes. Otherwise, these were Results
used according to their instructions for use (IFU; Z- Medica).
The bandage rolls were common cotton (AirWrap and Both models of AirWrap maintained their pneumatic pres-
™
AirWrap-XL Compression Bandages with Inflatable Bladder; sure for 6 hours, indicating that air was held well. No model
RevMedx). Bladders were centered over limb pressure trans- showed evidence of a leak, malfunction, or stress relaxation of
ducers; otherwise, wraps were used according to their IFU. the bladder walls (Figure 1).
The AirWrap-XLs were premarket prototypes.
Results of test duration showed caregiver performance by test
The following items were reused among tests. We used a 3-in. number, a surrogate of experience accrual (Table 3). Variabil-
wide roll of adhesive tape of silk-like cloth (NSN 6510-00- ity of data like blood loss occurred partly because whether the
926-8884). A nonpneumatic tourniquet was used for the tests; problem in need of troubleshooting occurred during bleeding
otherwise, it was used according to its IFU (C-A-T Resources). or during its control, blood loss and time variations depended
Bandage scissors were on hand (7.25-in long; NSN 6515-01-5 partly on how long it took to identify and fix the problem(s).
98-9737), as was a black Sharpie fine-point marker (NSN 7520- The first test duration was 17 minutes. On average, the inves-
00-312-6124; Newell Brands, https://www.sharpie.com/). A tigator’s speed improved moderately as times decreased expo-
pair of treatment gloves were used (NSN 6510-01-525-1975). nentially. Although later times were 6–7 minutes, a floor effect
existed due to a 3-minute period to hold manual pressure as
The clinical situation was to change for the emergency pro- noted in the dressing’s instructions (Figure 2). By using the 3
vider. Initially, the tourniquet-use situation was care under minutes as a numerator in a proportion of task duration, a
gunfire (also known as care under threat), after which it reciprocal ceiling effect averaged approximately 47% (3 min-
changed to emergency healthcare. The test was divided into utes/6.4 minutes) of the mean time for tests 10 through 15 as
halves called trials. A tourniquet trial preceded a trial of its experience was accrued (Figure 3).
conversion to a pressure dressing. The test steps included both
trial types and were in a set order (Table 2). Steps 38–43 oc- Tourniquet trial results showed that all 15 uses were effective
curred if so randomized. to stop bleeding (Table 4). All tourniquets were placed at the
correct site, stopped the pulse, and made the patient stable.
A manikin was used as described elsewhere. Briefly, the All tourniquet trials were satisfactory (“go” results). Mean
20
HapMed Leg Tourniquet Trainer (CHI Systems, http://www (± standard deviation [SD]) tourniquet pressure and blood loss
.chisystems.com) simulated an amputation. The scenario for were 222 ± 18.0mmHg and 146 ± 40.9mL, respectively. Ease
tourniquet application included an adult with a small build, of use (1, very difficult; 2, difficult; 3, neutral; 4, easy; 5, very
caregiving under gunfire, and a bleed-to-death time of 240 sec- easy) in each trial was 4. The tourniquet trial times were flat by
onds. The conversion scenario was identical, but it was emer- test number for both time to stop bleeding and trial duration.
gency care.
After the uniformly good results in each tourniquet trial, each
The manikin measured trial time and time to stop bleeding. test continued to its conversion trial, where results were worse
The manikin determined patient status (bleeding or stable), and more varied (Table 5). The initial attempt at wrapping was
trial status (go [satisfactory] or no go), tourniquet placement, effective in 73% of tests (n = 11 of 15). There were four times
its pressure, and blood loss. Data collected by the user in- (27%) when a need to troubleshoot recurrent bleeding was
cluded ease of use and test times (start, end). identified and a rewrap was executed. Most of these rewraps

TABLE 1 Materials
Product Type Product Name Maker and Website National Stock No.
Hemostatic Z-folded QuikClot Z-Medica Corp, https://quikclot.com/ 6510-01-562-3325
®
dressings, Combat Gauzes ™
7.5cm × 7m
Bandage rolls, Kerlix AMD Medtronic, https://www.medtronic.com/covidien/en-us/index.html 6510-01-503-2117
™
6 ply cotton, Antimicrobial Bandage
11.4cm × 3.7m Roll
Compression AirWrap Compression Revmedx, Inc., https://www.revmedx.com 4-in., 6530-01-643-5297
™
bandages Bandages with Inflatable 6-in., 6530-01-657-1978
Bladder
Nonpneumatic Combat Application C-A-T Resources, http://www.combattourniquet.com 6510-01-521-7976
tourniquet Tourniquet, Generation 7

Tourniquet Conversion Method | 45