LAVA TQ Doppler Functionality Study
Condition: Traumatic Hemorrhage
MeSH terms: Hemorrhage
Study type: Interventional

Summary: 
      This is a single-blinded, randomized clinical trial to determine if the Layperson Audiovisual
      Assist tourniquet's (LAVA TQ) ability to occlude arterial blood flow is non-inferior to that
      of the Combat Application Tourniquet (CAT).
    

Detailed description: 
      1. Background and Significance

           Trauma is the leading cause of death in the United States for people ages 1 to 44;
           uncontrolled bleeding is a leading cause of those deaths.1 Immediate hemorrhage control,
           even prior to the arrival of emergency medical services, can save lives during these
           emergencies. Since the launch of the Stop the Bleed (STB) campaign in 2015, the public
           has been empowered to stop life-threatening hemorrhage.2 One of STB's five objectives is
           to equip every bleeding control kit with audio and visual instructions; this has not yet
           been achieved. Commonly used tourniquets, such as the Combat Application Tourniquet
           (CAT) or Special Operations Forces Tourniquet (SOF-T), do not provide audio instructions
           and are not designed to provide feedback to facilitate tourniquet application. A device
           that could facilitate application and provide real-time instructions and feedback could
           be immensely beneficial to both the public and the DoD, especially to minimally or
           untrained people such as DoD civilians, contractors, and dependents on military
           installations. To achieve the above mentioned STB's objective, the research team at the
           National Center for Disaster Medicine and Public Health is devoted to develop a
           layperson tourniquet with audio-visual instructions and performance feedback.

           In January 2020, the research team conducted a pilot study to evaluate this novel
           layperson tourniquet in a community lay public sample recruited from at the NBC Health
           Expo in Washington, DC. Findings of this pilot study were promising. One highlight of
           the results was that the proportion of participants who applied the tourniquet correctly
           using the layperson tourniquet was significantly higher than that using the CAT (93.3%
           versus 6.3%). Moreover, for when asked about their favoritism toward the tourniquet,
           93.3% favored the novel layperson tourniquet, whereas 68.8% favored the CAT.

           In addition to research results, feedback provided by the participants in this pilot
           study allowed the research team and the manufacturing partner to make adjustments and
           improvements to the testing device. Now we have completed a pilot study evaluating
           overall user experience of the novel layperson tourniquet, our next step is to conduct a
           functionality study examining the function of this novel layperson tourniquet and to see
           if it performs on par with the CAT.

        2. Objectives/Specific Aims/Research Questions

           The objective of the study is to determine if the Layperson Audiovisual Assist
           Tourniquet (LAVA TQ)'s ability to occlude arterial blood flow is non-inferior to a
           Combat Application Tourniquet (CAT).

        3. Study Procedures

           This study will be a single blinded, randomized clinical trial. The study will be
           conducted in a room at USU's Multidisciplinary Laboratories.

           The study has two arms: SMART TQ is the experimental arm and CAT is the control arm. The
           study will consist of three groups of individuals:

             -  Medical professionals who apply the tourniquet (we will call this group "medical
                professionals" in this protocol).

             -  Volunteers who offer their legs for tourniquet application (we will call this group
                of individuals "study participants").

             -  Blinded observers who will use a Doppler to check and monitor pulse. Absence of the
                dorsalis pedis pulse will be used to indicate occlusion of blood flow. The pulse
                monitored by the blinded observers will be used as an outcome for this research
                study. The only person blinded in the study will be the person checking for a
                successful application by measuring the doppler pulse - that is the blinded
                observers. There will be a bedsheet, or similar screen, placed between the portion
                of the participant's leg that has the tourniquet applied and the participant's foot
                where the doppler pulse will be measured. In addition, the research team will
                provide blinded observers noise-canceling headphones to minimize the influence of
                audio instructions provided by the LAVA TQ.

           We will recruit two medical professionals and two blinded observers and consent
           volunteers (i.e., participants).

           Two medical professionals will attend a training session prior to the study. The session
           will allow the study team to verify that medical professionals can apply both types of
           tourniquets successfully. We anticipate this training session lasting no more than one
           hour and will recruit one participant for the training session.

           Upon the completion of the informed consent, participants will be assigned study ID
           numbers. The study steps are below:

             -  A study participant enters the study room, completing a demographic information
                sheet and taking blood pressure, and then lies down with the face and torso facing
                up.

             -  To capture the baseline dorsalis pedis (DP) pulse: A blinded observer uses a
                doppler ultrasound to check DP pulse, the artery pulse on the surface of the foot.
                Doppler ultrasound is a small medical ultrasound machine that uses high-frequency
                sound waves to measure the amount of blood flow through the arteries and veins. The
                doppler ultrasound probe will be placed on the exposed foot, a pulse detected, and
                the location where the pulse is detected on that foot will be marked with an "X"
                using a surgical marker, and the doppler probed removed. This marked location will
                be where the doppler probe is placed later to determine whether there is a pulse.

             -  The research team member will measure the circumference of the leg at the area of
                tourniquet application. To keep the application location consistent across all the
                participants, we will mark where on the leg the tourniquet should be placed for
                each application.

             -  A medical professional records which leg will be used for tourniquet application
                (left leg or right leg).

             -  The medical professional applies the tourniquet. This is the first application of
                the tourniquet.

             -  Upon the completion of the tourniquet application, the blinded observer records the
                presence or absence of a dopplerable pulse. A blinded observer again uses a doppler
                ultrasound probe to check the dorsalis pedis (DP) pulse, the artery pulse on the
                surface of the foot, at the previously marked "X" location on the foot.

             -  The medical professional removes the tourniquet and the study participant takes a
                break.

             -  The medical professional places a blood pressure cuff first and then places a
                tourniquet over the blood pressure cuff. This is the second application of the
                tourniquet. The blood pressure cuff will be attached to a pressure sensor to
                measure surface pressure under the tourniquet. The medical professional will
                tighten the tourniquet until the doppler pulse is eliminated. The medical
                professional will then read and record the pressure readings.

             -  The medical professional removes the tourniquet.

           The procedures will then be repeated to a participant's other leg for the other arm. For
           example, if a participant is initially assigned to the CAT and uses the right leg for
           tourniquet application. The participant will then be in the LAVA TQ arm for the left
           leg.

           Termination Procedures: For the first tourniquet application on each leg, the observer
           will use doppler ultrasound to assess the participant's foot for a present or absent
           dorsalis pedis pulse. The observer will make the assessment at the location previously
           marked with a surgical marker. As soon as the pulse is determined to be present or
           absent, the observer will verbally tell the medical professional, "remove the tourniquet
           now."

           For the second tourniquet application on each leg, the medical professional will tighten
           the tourniquet on top of the neonatal blood pressure cuff as described. The study team
           member will record the pressure. As soon as the pressure is noted, the study team member
           will tell the medical professional, "remove the tourniquet now."

           Participant Post-Application Assessment: Following the application of two tourniquets to
           both legs, the study team will ask the participant to rest while lying on the table for
           five minutes. After five minutes, the study team member will ask the participant the
           following questions:

             -  Do you have any persistent pain beyond mild aching at the application site?

             -  Do you have numbness, tingling, or other abnormal sensations?

             -  Does your leg feel weak?

           If the answer is yes to any question, the team member will ask the participant to rest
           for five more minutes and re-ask the questions. If the answer to any question is still
           yes, the study team member will recommend that the participant seek medical care at an
           emergency department or with the participant's physician. If the study team member or
           participant is concerned that they are experiencing a medical emergency, they will call
           9-1-1 and alert any of the medical professionals assisting with the study for
           assistance.

           If the answer to the questions is no, the study team member will ask the participant to
           walk up and down the hall in the MDL. The study team member will observe the participant
           ambulating. If the person feels normal while walking, they can be discharged from the
           study.

           The study team member will be advised to follow-up with their physician or emergency
           department for medical care if either leg develops worsening pain, swelling, redness,
           coldness, or bluish or pale color, or if they have shortness of breath or chest pain.
           The study team member will advise the participant that some mild local bruising or
           redness in the area of the tourniquet application may occur and that it does not require
           medical evaluation.

           In addition, given the LAVA TQ is an abbreviated investigational device, we will follow
           the abbreviation requirements specified by the FDA.

        4. Data Collection

           The outcome variables in the study are: 1. the participants' resting blood pressure, 2.

           the presence or absence of dorsalis pedis pulse after tourniquet application, and 3. the
           surface pressure reading when the tourniquet is tightened. At the beginning of the
           study, participants will be asked to complete a demographic information sheet. On this
           sheet, they will fill out their age, gender, race, and ethnicity.

        5. Statistical Considerations

      The primary outcome variable for this research study binary (successfully stop the pulse:
      yes/no) and we conducted a power analysis for a parallel group non-inferiority trial.
      Assuming the two arms have the same high successful rate, with 80% power, and define the
      non-inferiority limit as 10% (so that a difference bigger than this would matter in
      practice), we estimated sample size required for each group is 13 applications (at least), so
      a total sample size of 26 applications (at least). Given the potential missing data and to
      ensure we will have enough statistical power for the final analyses, we will set the total
      sample size of 40 applications for this study. Since the tourniquet will be applied to
      participants' both legs (not at the same time), each leg will be one application and one
      participant will be able to fulfill two applications. As such, we will recruit no more than
      20 participants for the study session and one additional participant for the training
      session.
    

Intervention name(s): Layperson Audiovisual Assist Tourniquet (LAVA TQ); Combat Application Tourniquet
Intervention type(s): Device; Device
Intervention description(s): The Layperson Audiovisual Assist Tourniquet is a hemorrhage control device designed to occlude blood flow in the event of limb hemorrhage. This device provides audiovisual instructions and feedback.; The Combat Application Tourniquet (CAT) is a hemorrhage control device designed to occlude blood blow in the event of a limb hemorrhage. The CAT utilizes a windlass rod design.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: This study will be a single blinded, randomized clinical trial.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Health Services Research