Our research focuses on innovatively applying mechanical arms and vascular blocking band to a hemorrhage model. We are investigating how the combination of controlled hemorrhage with free bleeding and controllable pressure can enhance the effectiveness of prehospital emergency interventions in cases of hemorrhagic shock. In the field of hemostasis at junctional areas, the femoral artery hemorrhage model is most used while the auxiliary artery hemorrhage model is unexplored.
Our model lays the foundation for hemostasis research in the axillary junctional area. In the future, our laboratory will focus on the development of new hemostatic devices for massive bleeding in junctional areas and the research of rapid hemostatic strategies. To begin transfer the sedated animal to the operating room and secure its limb in a supine position on the operating table.
Then puncture the ear vein with an intravenous indwelling needle. Using a scalpel, make an eight centimeter longitudinal skin incision from the thyroid cartilage to the manubrium. With blunt tip surgical scissors, dissect along the medial surfaces of the sternal hyoid muscles, deepen the dissection and make a one centimeter incision at the trachea.
Then insert a seven millimeter tracheostomy tube to a depth of six centimeters and connect it to the ventilator. Next, employ the cutdown technique for cannulation of the left carotid artery, requiring at least two operators. Using the tracheostomy incision, dissect the tissue lateral to the sternal hyoid muscle to isolate the left carotid artery from the surrounding fascia.
Elevate the artery with silk sutures using one hand while puncturing it with the needle in the other. Then administer five milliliters of 0.9%sodium chloride solution to verify needle placement. Advance the guide wire through the tube while retracting the needle.
Then using the introducer guided over the wire, extract the tube and insert the sheath. After insertion, remove both the introducer and the wire. To isolate the right carotid artery and jugular vein, perform a lateral dissection adjacent to the sternal hyoid muscle on the contralateral side.
Now, place a 7.0 French central venous catheter with dual ports into the right jugular vein and promptly link a transducer system for central venous pressure measurement. Connect lactated ringer solution to one port of the central line and administer a maintenance saline infusion through the other port to mitigate catheter occlusion. Next, introduce a 4.0 French arterial catheter equipped with a thermistor into the right carotid artery, connecting it to the cardiac monitor while simultaneously connecting the monitor's venous measuring unit to the central venous transducer.
Calibrate both the venous and arterial transducers to zero referencing the mid axillary line. Then use the cardiac monitor to continuously monitor and document the heart rate and systolic and diastolic blood pressures. To initiate hemorrhagic shock, withdraw blood from the left jugular vein at specific average rates over 20 minutes using baseline data collected at T zero.
Withdraw, 0.33 milliliters per kilogram per minute, 0.67 milliliters per kilogram per minute, and one milliliter per kilogram per minute for groups one, two, and three respectively. Use ultrasonography with doppler to map the axillary artery and distinguish arterial, venus, and neural structures in the axillary fossa. Align the probe perpendicular to the dermal layer above the pectorals muscle, allowing for the axillary arteries precise anatomical localization.
Then mark a 10 centimeter arc shaped incision as the surgical entry based on the anatomical landmarks established through ultras sonographic imaging. Partially removed the superficial and deep pectorals muscles to expose the axillary sheath. To expose the axillary artery, use a micro scissor to blunt, dissect the axillary sheath and isolate a six centimeter segment of the artery from the surrounding vein and brachial plexus.
Then place the red band at the proximal end and the green band at the distal end of the axillary artery segment to secure the vessel before inflicting injury. Tie up the two vascular blocking bands to temporarily block the blood flow. Using a micro scissor, create a two millimeter horizontal incision about one third of the vessel's perimeter.
Attach the mechanical arm of the external compression device to the side of the operating table. Connect the inflatable hemostatic balloon to the end of the arm. Then immobilize the flexible film pressure sensor at the central point on the surface of the inflatable hemostatic balloon to measure the direct pressure.
After installation, open the software. Click on the Connected device, select the single channel option and choose 1000 data points per second from the sampling rate menu. For the input channel, select Band display For the output channel, select Output display.
Before recording, ensure the pressure measurement system is calibrated to zero. Click the circular red button to start recording. To simulate external compression, target the mechanical arm on the axillary wound immediately after releasing the two vascular blocking bands manually inflate the hemostatic balloon to achieve local compression until the pressure reaches 210 millimeters of mercury.
Observe the device during compression to ensure that there is no displacement. After the external compression, click the red square button to stop data collection. Once the device is removed, weigh the gauze to calculate the blood loss under compression.
The mean blood loss after volume controlled hemorrhage in groups one, two, and three was 354.2, 714.4, and 1064.0 milliliters respectively representing 10%20%and 30%of the total blood volume. No statistically significant difference in blood loss under compression was observed among the three groups. The mean total blood loss for groups one, two, and three was 462.9, 893.0, and 1213.0 milliliters respectively corresponding to class one, two, and three hemorrhagic shock.
A marked increase was observed in heart rate across all groups in response to induced shock. The heart rate escalation was most pronounced during external compression and decreased upon its removal. The extent of heart rate elevation was directly proportional to the volume of blood withdrawn with group three showing the most significant increase followed by group two and group one.
