Haemostasis ~ The Blood Clotting Process

Haemostasis

Haemostasis is the process by which blood loss is prevented. This happens through three basic mechanisms:

  1. Vascular Spasm – blood vessel damage stimulates pain receptors to cause immediate smooth muscle contraction within its wall; this reduces blood loss rate for up to 30 minutes, during which other haemostatic mechanisms are triggered.
  2. Platelet Plug Formation – platelets which come into contact with damaged blood vessel parts begin to enlarge, become irregular, sticky, and start adhering to collagen fibres; ADP (adenosine diphosphate) and enzyme synthesis triggers the formation of other substances, activating more platelets to adhere to the original platelets, forming a platelet plug, which is then reinforced by fibrin threads.
  3. Blood Coagulation a.k.a. Blood Clotting -whilst blood within the vessels maintains its liquid state, blood outside the vessels thickens and forms a gel (serum) which separates from the liquid. Blood serum is blood plasma without its clotting proteins, whilst the gel is the clot, which contains insoluble fibres that trap the cellular components of the blood.
Retrieved from https://quizlet.com/185065266/hemostasis-vs-anticoagulation-and-thrombolysis-flash-cards/ on 22nd May 2022

Blood Coagulation

Blood coagulation is the process of clot formation – a process which involves various chemicals referred to as coagulation factors.

haemostasis coagulation factors
Retrieved from https://www.vetfolio.com/learn/article/hemostasis on 22nd May 2022

There are 3 basic stages for coagulation…

Stage 1: Formation of Prothrombin Activator

Stage 1 involves the formation of prothrombin activator, initiated by the extrinsic and intrinsic pathway of blood clotting.

Stage 2: Conversion of Prothrombin into Thrombin

Following the formation of prothrombin activator, it binds to Ca2+ ions (Calcium Ions), causing the conversion of prothrombin into thrombin.

Stage 3: Conversion of Fibrinogen into Fibrin

Thrombin and Ca2+ ions trigger the conversion of Fibrinogen (soluble) to Fibrin (insoluble).

Thrombin activates Factor XIII (Antihemophilic Factor) which strengthens and stabilises the fibrin clot.

Through a positive feedback effect, Thrombin accelerates the formation of prothrombin activator through Factor V (Proaccelerin), which further accelerates the production of more Thrombin.

The formed clot plugs the ruptured area of the blood vessel, preventing haemorrhage. This is followed by permanent repair of the blood vessel.

Additional Factors related to Haemostasis

Vitamin K

Efficient clotting requires Calcium as well as Vitamin K, which is required for prothrombin formation and other coagulation factors by the liver. Vitamin K is formed by the human intestinal bacteria, and can also be found in foods such as spinach, cabbage, cauliflower, and liver.

Thrombosis

Thrombosis is the formation of a clot (thrombus) within an intact blood vessel. Thrombosis is caused within blood vessels containing sluggish blood flow, and when platelets stick to fatty deposits on the blood vessels’ inner surface. A thrombus can either dissolve or else grow and eventually block the blood vessel.

Embolism

Embolism happens when a part of the thrombus breaks off from its original site forming an embolus, moves along the blood stream until it reaches a small blood vessel and blocks it.


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Wound Care In Nursing Practice

The skin is an organ responsible for many of the body’s reactions to the environment, such as protection, temperature control and sensory information. It provides non-verbal information on one’s condition. It also has a profound effect on the psychological well-being of the individual. But like every other organ, it needs to be well cared for to provide optimum functionality. Wound care in nursing practice requires the knowledge of various techniques used in the assessment, treatment and care of the patient with one or multiple wounds. Techniques include debridement, cleaning, bandaging, as well as liaising with the multi-disciplinary team for better and quicker treatment.

Optimum wound care requires:

  • Good relevant patient history taking
  • Detailed documentation
  • Identification of the patients requiring a multidisciplinary approach
  • Early complication detection and referral to the appropriate specialists
  • Patient education
  • Awareness on the psychosocial impact that the skin has on the individual

Wound Healing Process

A wound is the discontinuity of the skin, mucous membrane or tissue caused by physical, chemical or biological insult. Wound healing requires:

  1. The replacement of injured tissue with new tissues
  2. An increased consumption of energy
wound care in nursing practice
Distinct and overlapping phases of wound healing – Retrieved from https://parjournal.net/article/view/1211 on 26th October 2021

HAEMOSTASIS – The body aims to stop the bleeding through vasoconstriction, platelet formation, etc. In other words, haemostasis is the body’s natural physiological response for the prevention and stopping of bleeding.

REMODELLISATION – Takes up to around 2 years of healing. This is why a visibly healed wound can just open by itself, even if untouched. Some ‘simple’ dry skin can trigger a wound to re-open.

Moist Wound Healing in Wound Care

In moist occlusive and semi-occlusive environments, epithelialisation happens at twice the rate when compared to dry environments. Moist wound healing can be achieved through the use of advanced wound care dressings. However, a wet environment can be detrimental to wound care, as this may lead to maceration as well as tissue breakdown. The key to wound healing is to keep the wound bed balanced between dry and wet – find moisture balance!

NOTE: Iodine-impregnated dressings and silver dressings can be used if wound exudate is present. Alginates, which are made of seaweed extract, can absorb exudate. Aquacel AG has the ability to absorb up to 3 times more than alginates.

NOTE: Moist wound healing shouldn’t be used for necrotic digits (fingers and toes) due to ischaemia and/or neuropathy. Necrotic digits should be kept thoroughly dry. If kept wet, infection may travel up through the whole leg, leading to the amputation of not just one toe but a whole foot.

wound care in nursing practice
Retrieved from https://www.slideshare.net/sungwooks/wound-care-59702625 on 26th October 2021

Acute VS Chronic Wounds – chronic wounds happen when things go wrong. This usually happens within the inflammatory phase of wound healing (hours to days following wound infliction).

wound care in nursing practice
Retrieved from https://www.slideshare.net/sungwooks/wound-care-59702625 on 26th October 2021

Problem Wounds – These are wounds that don’t heal due to other local issues, such as infections, individuals on steroidal drugs, immunocompromised individuals, etc.

wound care in nursing practice
Retrieved from https://www.slideshare.net/sungwooks/wound-care-59702625 on 26th October 2021

Local Factors Affecting Wound Healing

Wound healing can be delayed by various factors local to the wound itself. Such factors include:

  • local infection
  • necrotic tissue or foreign body presence
  • poor blood supply / low oxygen perfusion
  • venous stasis – loss of proper vein function of the legs that would normally carry blood back towards the heart
  • lymph stasis – lymph circulation disorder that leads to oedema
  • tissue tension – a state of equilibrium between tissues and cells that prevents over-action of any part
  • haematoma and dead space
  • large defect or poor opposition
  • recurrent trauma
  • x-ray irradiated area
  • wound location – eg. wound over joint

Complications of Wound Healing

  • Infection – red, swollen, painful wound with discharge, pus or bad smell
wound care in nursing practice
Retrieved from https://www.sciencephoto.com/media/108432/view/infected-wound-of-the-thumb on 26th October 2021
  • Avoidable scar
wound care in nursing practice
Retrieved from https://the-medical-negligence-experts.co.uk/claim-types/scarring-negligence/ on 26th October 2021
  • Excess healing-keloid and hypertrophic scar
wound care in nursing practice
Retrieved from https://psderm.com/keloids/ on 26th October 2021
  • Skin pigmentation
wound care in nursing practice
Retrieved from https://dermnetnz.org/topics/postinflammatory-hyperpigmentation on 26th October 2021
  • Marjolin ulcer-occurs due to scar tissue
Retrieved from https://en.wikipedia.org/wiki/Marjolin%27s_ulcer on 26th October 2021
  • Contractures
Retrieved from https://www.saebo.com/contracture/ on 26th October 2021
  • Incisional hernia and wound dehiscence
Retrieved from https://www.woundsource.com/patientcondition/surgical-woundshttps://www.woundsource.com/patientcondition/surgical-wounds on 26th October 2021

Wound Descriptive Terms for Wound Care

  • Necrotic Eschar
Retrieved from https://www.woundsource.com/blog/knowing-difference-between-scabs-and-eschar on 26th October 2021
  • Necrotic Slough
Retrieved from https://www.researchgate.net/figure/Necrotic-skin-covered-with-slough-and-pus-exposing-underlying-fascia-case-number-1_fig2_23560895 on 26th October 2021
  • Infective
wound care in nursing practice
Retrieved from https://www.sciencephoto.com/media/108432/view/infected-wound-of-the-thumb on 26th October 2021
  • Granulation
Retrieved from https://www.woundsource.com/blog/getting-know-granulation-tissue-and-what-it-means-wound-care on 26th October 2021
  • Hyper-granulation
Retrieved from https://sanaramedtech.com/blog/how-to-identify-treat-hypergranulation-tissue/ on 26th October 2021
  • Poor quality granulation
Retrieved from https://www.researchgate.net/figure/Macroscopically-visible-poor-granulation-and-signs-of-infection-observed-on-the-9-th_fig1_256118693 on 26th October 2021
  • Epithelialisation
Retrieved from http://www.plasmamedicalsystems.com/2/medical/clinical-treatment-examples/treatment-of-a-surgical-site-infection-with-plasma-one/ on 26th October 2021
  • Maceration
Retrieved from https://www.healthline.com/health/macerated-skin on 26th October 2021
Retrieved from https://slideplayer.com/slide/12696492/ on 26th October 2021

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