臨床上的血管介入性手術，如心導管檢查及植入血管支架，經常以股動脈作為導管進入的部位。在術後股動脈穿刺的止血上，一般會以手動加壓(manual compression, MC)進行止血，然而MC 所耗費的止血時間長(約10 到20 分鐘)，且持續性的加壓易讓患者感到疼痛不適。而血管止血器(vascular closure devices, VCDs)改善了MC 的缺點，VCDs 僅需約5分鐘就可達到止血效果，讓患者可以更早下床活動，但由於裝置操作複雜、成本較高等因素，使VCDs 應用上僅佔所有股動脈止血手術的40％。
有鑑於此，本研究提出新型的可降解股動脈穿刺止血器，透過凍融循環將具有生物可降解性的聚乙烯醇 (polyvinyl alcohol, PVA)與明膠(Gelatin)製作成圓管型的水凝膠止血器，藉由PVA/Gelatin 水凝膠材料吸水可膨脹的特性，將完全乾燥的止血器在經由血管鞘置入股動脈傷口後，吸收血液與水分在5 分鐘內迅速膨脹以達封堵傷口之目的。此方法不僅避免需長時間止血的手動加壓，同時改善VCDs 在使用上較複雜的操作流程。
本研究將不同比例的PVA/Gelatin 水凝膠材料製成水凝膠試片與直徑為8mm(股動脈直徑大小)圓管型的止血器原型，將其乾燥後放置於水中，測試材料吸水膨脹後的結構完整性，及探討不同厚度對吸水膨脹時間和擴張力之影響，並建立股動脈模擬環境之平台，測試在股動脈的血壓(76mmHg)與血流量(284ml/min)環境下，止血器原型是否能順利擴張及貼合管壁，並以此建立適合作為股動脈可降解止血器的設計參數。
論文實驗結果顯示，製作壁厚為1mm，比例為7:3 的PVA/Gelatin 水凝膠止血器原型，其管徑可在5 分鐘內吸水膨脹至8mm，並且在模擬股動脈的血壓和血流環境測試中，證明此比例與厚度之參數可提供足夠的擴張力，使其順利貼合並維持固定於管壁，成功符合止血器的止血條件。
另外，經由公式推算，在乾燥後的止血器原型，可順利收縮進6F(2mm)
的導管內。

In clinical vascular interventional operations, such as cardiac
catheterization and implantation of vascular stents, the femoral artery is often
used as the catheter entry site. In the hemostasis of femoral artery puncture
after surgery, manual compression (MC) is generally used for hemostasis.
However, MC takes a long time to stop bleeding (approximately 10 to 20
minutes), and the continuous compression makes the patient feel painful and
uncomfortable. Vascular closure devices (VCDs) improve the shortcomings of
MC, VCDs only need about 5 minutes to achieve hemostatic effect, so that
patients can get out of bed earlier. However, due to the complicated operation
of the equipment and the high cost, the application of VCDs only accounts for
40% of all femoral artery hemostasis operations.
In view of this, this study proposes a new degradable femoral artery
puncture hemostatic device. Through freeze-thaw cycles, biodegradable
polyvinyl alcohol (PVA) and gelatin are made into a tubular hydrogel
hemostatic device, by PVA/Gelatin hydrogel material absorbs water swelling
properties, placing a completely dry hydrogel hemostatic device into the
femoral artery wound through the vascular sheath, absorb blood and water
and expand rapidly within 5 minutes to seal the wound. This method not only
avoids manual compression that requires a long time to stop bleeding, but also
improves the complicated operation process of using VCDs.
In this study, different ratios of PVA/Gelatin hydrogel materials were
made into hydrogel test pieces and tubular hemostatic test pieces with a
diameter of 8mm (femoral artery diameter). After they were dried, they were
IV
placed in water to test the structural integrity of the material, and to explore
the influence of different thickness on the water swelling time and expansion force, and establish a platform for the femoral artery simulation environment
to test whether the hemostatic device test piece can smoothly expand and fit
the tube wall under the femoral artery blood pressure (76mmHg) and blood
flow (284ml/min) environment, so as to establish a suitable femoral artery
parameters of degradable hemostatic device.
The results has shown that the PVA/Gelatin hydrogel hemostatic device
test piece with a wall thickness of 1mm and a ratio of 7:3 be able expanded to
a diameter of 8mm in 5 minutes by absorbing water, and it can simulate the
blood pressure and blood pressure of the femoral artery. In the test of the flow
environment, it is proved that the parameters of this ratio and thickness can
provide enough expansion force to make it fit smoothly and remain fixed on
the tube wall, and successfully meet the hemostatic conditions of the
hemostatic device. Calculated by the formula, the size after being dried can be
smoothly shrunk into the 6F (2mm) catheter.

[1]http://www.anscare.co/chinese/educations/detail.php?dpid=15
[2]Noori, V. J., & Eldrup-Jørgensen, J. (2018). A systematic review of
vascular closure devices for femoral artery puncture sites. Journal of vascular
surgery, 68(3), 887-899.
[3]Dauerman, H. L., Applegate, R. J., & Cohen, D. J. (2007). Vascular closure
devices: the second decade. Journal of the American College of Cardiology,
50(17), 1617-1626.
[4]https://evtoday.com/articles/2015-jan/vascular-closure-device-update
[5]Noori, V. J., & Eldrup-Jørgensen, J. (2018). A systematic review of
vascular closure devices for femoral artery puncture sites. Journal of vascular
surgery, 68(3), 887-899.
[6]Bechara, C. F., Annambhotla, S., & Lin, P. H. (2010). Access site
management with vascular closure devices for percutaneous transarterial
procedures. Journal of vascular surgery, 52(6), 1682-1696
[7] https://thoracickey.com/vascular-access-and-closure/
[8]Khan, S., Ullah, A., Ullah, K., & Rehman, N. U. (2016). Insight into
hydrogels. Designed Monomers and Polymers, 19(5), 456-478.
[9]https://www.sigmaaldrich.com/catalog/product/aldrich/363146?lang=en&r
egion=TW
[10]Lozinsky, V. I., & Plieva, F. M. (1998). Poly (vinyl alcohol) cryogels
employed as matrices for cell immobilization. 3. Overview of recent research
and developments. Enzyme and microbial technology, 23(3-4), 227-242
[11]Kamoun, E. A., Chen, X., Eldin, M. S. M., & Kenawy, E. R. S. (2015).
Crosslinked poly (vinyl alcohol) hydrogels for wound dressing applications: A
review of remarkably blended polymers. Arabian Journal of chemistry, 8(1),
1-14.
[12]Peppas, N. A. (1975). Turbidimetric studies of aqueous poly (vinyl
alcohol) solutions. Die Makromolekulare Chemie: Macromolecular
Chemistry and Physics, 176(11), 3433-3440.
[13]Zhang, H., Zhang, F., & Wu, J. (2013). Physically crosslinked hydrogels
from polysaccharides prepared by freeze–thaw technique. Reactive and
Functional Polymers, 73(7), 923-928
[14]Pezron, I., Djabourov, M., & Leblond, J. (1991). Conformation of gelatin
chains in aqueous solutions: 1. A light and small-angle neutron scattering
71
study. Polymer, 32(17), 3201-3210.
[15]Bajpai, A. K., & Saini, R. (2005). Preparation and characterization of
biocompatible spongy cryogels of poly (vinyl alcohol)–gelatin and study of
water sorption behaviour. Polymer international, 54(9), 1233-1242.
[16] https://scitechvista.nat.gov.tw/c/skYW.htm
[17]Mahnama, H., Dadbin, S., Frounchi, M., & Rajabi, S. (2017). Preparation
of biodegradable gelatin/PVA porous scaffolds for skin regeneration. Artificial
cells, nanomedicine, and biotechnology, 45(5), 928-935.
[18]Ceylan, S., Göktürk, D., & Bölgen, N. (2016). Effect of crosslinking
methods on the structure and biocompatibility of polyvinyl alcohol/gelatin
cryogels. Bio-medical materials and engineering, 27(4), 327-340.
[19]Liu, Y., Vrana, N. E., Cahill, P. A., & McGuinness, G. B. (2009).
Physically crosslinked composite hydrogels of PVA with natural
macromolecules: structure, mechanical properties, and endothelial cell
compatibility. Journal of Biomedical Materials Research Part B: Applied
Biomaterials, 90(2), 492-502.
[20]Lim, K. S., Alves, M. H., Poole-Warren, L. A., & Martens, P. J. (2013).
Covalent incorporation of non-chemically modified gelatin into degradable
PVA-tyramine hydrogels. Biomaterials, 34(29), 7097-7105.
[21]Marrella, A., Lagazzo, A., Dellacasa, E., Pasquini, C., Finocchio, E.,
Barberis, F., & Scaglione, S. (2018). 3D porous gelatin/PVA hydrogel as
meniscus substitute using alginate micro-particles as porogens. Polymers,
10(4), 380.
[22]Spector, K. S., & Lawson, W. E. (2001). Optimizing safe femoral access
during cardiac catheterization. Catheterization and cardiovascular
interventions, 53(2), 209-212.
[23]PARK, M. K., & GUNTHEROTH, W. G. (1970). Direct blood pressure
measurements in brachial and femoral arteries in children. Circulation, 41(2),
231-237.
[24]Holland, C. K., Brown, J. M., Scoutt, L. M., & Taylor, K. J. (1998).
Lower extremity volumetric arterial blood flow in normal
subjects. Ultrasound in medicine & biology, 24(8), 1079-1086.