Performance Evaluation of the Solo-T and the Combat Application Tourniquet in a Perfused Cadaver Model.

PURPOSE: We evaluated a 10.2-cm-wide, minimally elastic, adhesive wrap-based tourniquet (Solo-T or ST) alongside a 3.8-cm-wide windlass-based tourniquet (Combat Application Tourniquet Generation 7, or CAT) to determine if the tension wrap-tightened ST could deliver hemorrhage control equivalent to the windlass-tightened CAT. METHODS: A cadaver model was used to simulate lower-thigh femoral arterial hemorrhage at "normal" (146 ± 5mmHg) and "elevated" (471 ± 3mmHg) perfusion pressures (mean ± standard error). Three study participants used the ST and CAT to control hemorrhage during 48 timed trials. Arterial occlusion was established by Doppler ultrasound and tourniquet performance was quantified by under-tourniquet pressure cuffs. RESULTS: Participants achieved 100% (24/24) occlusion success rates and reported similar ease of use for both tourniquets. Occlusion and application times (mean ± standard error) were similar (p > .05) for the ST and CAT under "normal" (occlusion, ST: 25 ± 2 seconds, CAT: 22 ± 2 seconds; application, ST: 27 ± 2 seconds, CAT: 26 ± 2 seconds) and "elevated" (occlusion, ST: 24 ± 7 seconds, CAT: 24 ± 7 seconds; application, ST: 25 ± 7 seconds, CAT: 25 ± 7 seconds) perfusion alike. The ST mean completion pressures (mean ± standard error) were > 40% lower than the CAT under both "normal" perfusion (ST: 110 ± 20mmHg; CAT: 210 ± 30mmHg; p = 0.009) and "elevated" perfusion (ST: 190 ± 50mmHg; CAT: 340 ± 30mmHg; p = 0.03). CONCLUSION: The adhesive wrap-based ST tourniquet delivered equivalent hemorrhage control performance at significantly lower completion pressures than the CAT.

Investigative study of hemodilution ratio: 4Vs for vein diameter, valve, velocity, and volumetric blood flow as factors for optimal forearm vein selection for intravenous infusion.

BACKGROUND: Multimodal research and guidelines recognize veins in the forearm used for peripheral intravenous catheter (PIVC) insertion can optimize dwell time. Yet, many PIVCs are still placed in areas of flexion or suboptimal locations such as the back of the hand causing premature failure of >50%. This study identified characteristics of the forearm cephalic vein that make the anatomical location highly successful for PIVC insertion. The goal was to increase the understanding of the human vasculature in association with fluid mechanics in veins above the wrist and below the antecubital fossa. METHODOLOGY: A prospective in-vivo study with 10 consented healthy human volunteers (HHVs) was performed with Color Pulse Wave Doppler Ultrasound that captured high-resolution video and images of vein diameter, velocity of blood flow, and location of venous valves in the forearm. RESULTS: Forearm vein diameter was not directly correlated with higher or lower Velocity of Blood Flow (0.58 cm = 3.0 cm/s). However, Volumetric Blood Flow rates tended to be lower (2.51-8.28 mL/min) with Vein Diameters smaller than 0.29 cm. Ultrasound assessments and Volumetric Blood Flow calculations confirmed natural turbulence in blood and retrograde blood reflux correlated with venous valves opening and closing. Areas of turbulence, with pulse flushing, created backflow with retrograde blood flow around and into the catheter. CONCLUSIONS: Placement of long PIVCs in the cephalic veins of the upper forearm yield adequate flow and hemodilution capacity for veins with at least a 3 to 1 hemodilution ratio. The data from this study, along with previous research, suggest that PIVC placement in the cephalic vein, based on selection criteria, may help to reduce or eliminate intravenous complications such as chemical or mechanical thrombophlebitis causing premature catheter failure. Application of these investigational principles may result in better outcomes and catheter longevity for patients who require intravenous infusions.