Haemostasis script - group assessment PDF

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Haemostasis

Haemostasis is the natural process that stops bleeding when an injury occurs. It involves three separate steps: (1) vasoconstriction (2) platelet plug formation and (3) coagulation (lumen, n.d, 2017, para 1).

Vasoconstriction involves the narrowing of blood vessels, which increases blood pressure but can also decrease blood loss and flow (lumen, n.d, 2017, para2). It is caused by the hormone thromboxane A 2 from injured epithelial cells and activated platelets, direct injury to vascular smooth muscle, and nervous system reflexes from pain (lumen, n.d, 2017,para 10). Vasoconstriction lasts for only a few minutes during the haemostasis process. During the inflammation that comes after the injury, it is replaced by vasodilation as the healing process is beginning (lumen, n.d,2017, para10).

Platelets adhere to the damaged region to establish a temporary seal in the break of the vessel wall, called a platelet plug (lumen, n.d, 2017,para 14). These platelets then release factors to warrant further platelet activation, continuing the platelet plug formation, while different factors preserve vasoconstriction and stimulate coagulation (lumen, n.d, 2017, para 14). Platelets stick to the collagen fibres in the vessel wall by becoming filamentous and adhesive due to the von Willebrand factor. Platelets bind fibrinogen and the von Willebrand factor to stick together and seal the break within the endothelium (lumen, n.d, 2017, para 17). In the case of healing the wound, platelets also release chemicals into the plasma to aid further with haemostasis, amongst them are adenosine diphosphate (ADP) which permits further platelets to stick to the site (Morgan, 2019).

There are three pathways that divided coagulation cascade: the intrinsic pathway, the extrinsic pathway, and the common pathway (lumen, n.d, 2017, para 22) The intrinsic pathway takes place when negatively charged molecule contact creates a

cascade of elements that produce factor X. The extrinsic pathway happens when tissue damage causes the release of tissue factor, producing a smaller cascade that generates factor X. The common pathway combines both pathways as factor X is utilized to produce thrombin from prothrombin (lumen, n.d, 2017, para 23).

The coagulation cascade accumulatively strengthens the platelet plug. Coagulation can be dangerous if blood clots form and obstruct other blood vessels. Prolonged immobility can also cause blood clots if blood pools (World Health Organization, 2020, para 1). Whilst the coagulation cascade is vital for wound healing and haemostasis, it can also cause many issues. Any blood clot that detaches without being dissolved and travels through the bloodstream to a different location, is an embolism. If it blocks an artery that supplies blood to an organ or tissue, it can cause a stroke, pulmonary embolism or even a heart attack (Johns Hopkins, n.d).Furthermore, any deficiency of clotting cofactors, such as vitamin K or calcium, will create a diminished capacity for blood to coagulate, which can contribute to haemorrhage and excessive bleeding (Palta at. el, 2014).

In summary, haemostasis is a delicate process that allow our bodies to stop bleeding and to begin to heal. Without completing the three steps, vasoconstriction, platelet plug formation and coagulation, the complex balance of how our body functions is disrupted and as a result there are severe complications.

References: 1) Johns Hopkins Medicine (n.d.) Pulmonary Embolism. Retrieved from https://www.hopkinsmedicine.org/health/conditions-and-diseases/pulmonaryembolism 2) Lumen Learning (n.d.). (2017).Hemostasis. Retrieved from: https://courses.lumenlearning.com/boundless-ap/chapter/hemostasis/ 3) Morgan, Y. (2019). Surgical Wound Healing. The Dissector: Journal of the Perioperative Nurses College of the New Zealand Nurses Organisation, 47(1), 34+. Retrieved from https://link-galecom.ezp01.library.qut.edu.au/apps/doc/A588342227/HRCA? u=qut&sid=HRCA&xid=43096b88 4) Palta, S., Saroa, R., & Palta, A. (2014). Overview of the coagulation system. Indian journal of anaesthesia, 58(5), 515–523. https://doi.org/10.4103/0019-5049.144643 5) Weisel, JW, Litvinov, RI. Red Blood Cells: the Forgotten Player in Haemostasis and Thrombosis. J Thromb Haemost 2019; 17: 271– 82. 6) World Health Organisation (2020) Immobility, circulatory problems and deep vein thrombosis. Retrieved from:https://www.who.int/news-room/q-a-detail/airtravel-advice

Images: 1) Anonymously. (2014). Blood Clot Formation - Coagulation Factors https://makeagif.com/gif/blood-clot-formation-coagulation-factors-plateletsCFddbb?position=5 2) Big Red. (2017) This Guy Could Give Paulo Miyao a Butt Scooting Run For His Money. https://www.reddit.com/r/bjj/comments/76fjtj/this_guy_could_give_paulo_miya o_a_butt_scooting/ 3) Bernal Studio. (2019) Primary and Secondary Hemostasis. https://bernalstudio.com/projects/XqZO3 4) Designua. (2020) Wound Healing. https://www.shutterstock.com/imagevector/wound-healing-process-hemostasis-inflammatory-proliferative1340261516 5) Doss, Will. (2019) Newly Discovered Mechanism May Control Inflammation. https://news.feinberg.northwestern.edu/2019/08/newly-discoveredmechanism-may-control-inflammation/ 6) EJCRUZ. (2018) https://makeagif.com/gif/vasoconstrictionmpg-ioNbxM

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