01, Wound care

[byungin]

Anatomy of the Skin
The skin is made up of a thin outer layer (epidermis) and a thicker outer layer (dermis). Below the dermis is the subcutaneous tissue, which contains fat. Buried in the skin are nerves,  sebaceous glands, and sweat glands.

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Baranoski S, Ayello E. Skin: An essential orgam. In:Wound care     47-60.
Jones V, Bale S, Harding K. Acute and chronic wound healing. In:Wound care     61-78

Skin thickness varies from 0.5 (eyelids) mm to 6 mm (soles). The epidermis is a thin, avascular layer that regenerates itself every 4 to 6 weeks. The function of the epidermis is protection from water loss, friction, and irritants. The dermis is the most important part of the skin and its functions are to provide tensile strength and to protect the underlying muscle, bones, and organs. The function of the subcutaneous tissue is to promote a blood supply to the dermis for regeneration.
Staphylococcus aureus and Staphylococcus epidermis which tolerate salt and yeast are found commonly on the skin. In the epidermis, keratinocyte migrate up from the bottom sigle layer of cells to the surface. This cellular migration takes 28 days and is affected by aging and chemotherapy. In elderly people. the decrease of keratinocyte migration upward in aging skin accounts in part for the longer wound healing rates. Loss in dermal thickness and subcutaneous fat results in reduction of protective functions in elderly people. Subcutaneous fat loss is prominent in face, dorsal aspect of the hands, shins, and plantar aspect of the foot. 

Wound Healing Process

Wound healing events
The process of wound healing is usually divided into four phases- hemostasis, inflammatory, proliferation, and maturation. Cells undergo biological changes to facilitate hemostasis, combat infection, migrate into the wound space, deposit a matrix, and contract to close the defect. Wound closure is not a marker of healing completion. Remodeling continues to change for up to 18 months post-closure, and the closed wound is still vulnerable during this period.
[Baranoski S, Ayello E. Skin: An essential orgam. In:Wound care     47-60.
[Jones V, Bale S, Harding K. Acute and chronic wound healing. In:Wound care     61-78]

A clot forms and inflammatory cells debride injured tissue during the inflammatory phase. Epithelialization, fibroplasia, and angiogenesis occur during the proliferative phase. Meanwhile, granulation tissue forms and the wound begins to contract. Finally, during the maturation phase, collagen forms tight cross-links to other collagen and with protein molecules, increasing the tensile strength of the scar.

1, Hemostasis
The disruption of tissues following injury causes hemorrhage. Platelet aggregation and coagulation result in clog formation and hemostasis. A fibrinous clot acts as a preliminary matrix within the wound space into which cells can migrate. After clot formation, fibrinolysis, part of body's defense mechanism, is activated. Fibrinolysis dissolves the clot to allow ease of further cell migration into the wound space.

2, inflammatory phase
The inflammatory phase occurs immediately following the injury and lasts approximately 6 days. As the fibrin clot is degraded, the capilaries dilate allowing fluid into the wound and help bind neutrophils to bacteria. The chemicals released from damaged cells initiate inflammatory process. Leukocytes, primarily polymorphonuclear leukocytes, are the primary cells of the inflammatory process. Leukocytes remove the devitalized tissue. Macrophages which arrive 2-3 days after injury are essential to wound healing and perhaps are the most important cells in the early phase of wound healing. Macrophages phagocytose debris and bacteria. Macrophages also secrete collagenases and elastases, which break down injured tissue and release cytokines. Lymphocytes and T lymphocytes migrate into the wound during the inflammatory phase, approximately 72 hours following injury. Induration, heat, redness, and swelling are not infection but part of the normal healing process.

3, proliferation phase
The proliferation phase begins 3 days after an injury and lasts for a few weeks.
The fibroblastic phase occurs at the termination of the inflammatory phase and can last up to 4 weeks. Formation of granulation tissue synthesized by fibroblasts is a central event during this phase. Fibroblasts appearing withing 3 days of injury move into the wound space and produce a matrix of fibronectin, collagens, glycosaminoglycans, and proteoglycans. Granulation tissue formation occurs 3-5 days following injury and overlaps with the preceding inflammatory phase. Collagen synthesis begins approximately 3 days after injury and may continue at a rapid rate for approximately 2-4 weeks. Angiogenesis is an essential part of wound healing with formation of new vessels from existing endothelial cells at the wound edge. Epithelialization is the formation of epithelium over a denuded surface, which begins within a few hours of tissue injury. Incisional wounds, if skin edges are brought together, are epithelialized within 24-48 hours after injury. The epithelilal cells start to migrate across the matrix from the wound edges, sweat and sebaceous glands, and hair follicles. If skin edges are not brought together, granulation tissuegradually covers the wound and contraction brings the skin edge together, and wound closure completes with scar.
Wounds in a moist environment demonstrate a faster and more direct course of epithelialization. Occlusive and semiocclusive dressings applied in the first 48 hours after injury may maintain tissue humidity and optimize epithelialization. Contraction, defined as the centripetal movement of wound edges that facilitates closure of a wound defect, begins 5 days after injury almost concurrently with collagen synthesis. Cells organize their surrounding matrix, acting to reduce the healing time. Fibroblasts provide the force for this contraction. Contraction is critical for large wounds, but may not be important in a sharply incised, small and noninfected wound.

4, Maturation phase
The maturation phase normally starts 7 days after injury and lasts for 1 year or more. Collagen deposition and remodelling contribute to the increased tensile strength of the wound, which is restored to 20 % of normal skin within 3 weeks of injury. As healing continues, the skin gradually reaches a maximum of 70 - 80 % tensile strenth. Cellularity and vascularity are gradually reduced. Healed wound never achieve the same tensile strengh as uninjured skin.
The scar is the final product of wound healing. and maturation or remodeling may continue indefinitely.
[Thomas Romo III. Wound Healing, Skin.(Last Updated: December 5, 2005)  Available URL from:http://www.emedicine.com/ent/topic13.htm]

Healing in Acute and Chronic Wound
An acute wound is defined as a disruption in the integrity of the skin and underlying tissue that progress through the healing process in a timely and uncomplicated manner, such as surgical and traumatic wounds which heal by primary intension. A chronic wound is defined as an wound that fail to progress through a normal and timely sequence of repair. Chronic wounds are associated with diabetes, ischemic disease, pressure demage, and inflammatory disease, and heal by secondary intension.
The first physiological difference of chronic wounds is prolonged inflammation due to recurrent physical trauma, ischemic injury, bacterial contamination, and foreign bodies. Secondarily, chronic wounds are typically characterized by full-thickness tissue loss, so that epithelialization takes longer due to the loss of appendage (the source of epithelial cells)     

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Wound Healing: The Skin

Primary Healing
 Definition: healing of an incision or severing wound of the skin; also called healing by first intention; damage is minimal & wound edges are closely apposed
 Process of primary healing:
-         Incised wound filled by blood clot
-         Reepithelialization & revascularization begin
-         Clot becomes scab & collagen formation begins
-         New epithelium (with lack of pigment) is formed & scar tissue is formed
-         *Scar resembles incised wound*

Secondary Healing
Definition: healing in wounds whose edges are not closely apposed; also called healing by second intention; larger wounds with more debris that must be removed & have a large gap to be filled by replacement tissue; longer healing process
Process of secondary healing:
-         Blood clot fills wound
-         Granulation tissue fills gap, reepithelialization begins, & scab forms
-         Wound contraction (due to myofibroblast)
-         Granulation tissue is organized
-         Scar tissue forms
-         *Scar does not resemble original shape of wound*

Wound contraction: the shape of the scar is determined by the movement of the wound’s edges toward its center

* LAKE SUPERIOR STATE UNIVERSITY STUDENT WEB PAGE. Healing. Available from URL:http://student.lssu.edu/~dspisso/he232/chap4.htm
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Wound Care
The aim of treatment of skin break is protecting environmental bacteria, intervening further damage, preventing dryness, and enhancing proliferation of the epithelial cells. Although lacerations(or cuts), punctures(or stab wound), abrasions, scrapes,  burns, and pressure ulcer occur by different causes, treatments are almost similar.
피부가 손상된 상태를 상처(傷處, 창상(創傷)이라고도 함)라고 한다. 상처 치료의 목적은 세균이 상처에 침범하지 않게 하고, 상처가 커지지 않게 하며, 건조되는 것을 방지하는 것이며, 궁극적으로는 표피세포를 빨리 증식시켜 피부 결손을 메꾸는 것이다. 상처의 종류는 원인에 따라 '찢긴 상처 (열창(裂創), lacerations, cuts)', '찔린 상처 (자창(刺創), punctures, stab wounds)', '까진 상처(찰과상(擦過傷), abrasions, scrapes),' '벤 상처 (절창(癤瘡), incised wound)', 화상, 욕창 등으로 나누지만 치료 방법은 거의 비슷하다.

Management rule is as followings. (Fig 1~5)
(a) Cleaning
(b) Bleeding Control
(c) Dressing: primary dressing, secondary dressing, covering
(d) Taping

그림2, Apply direct pressure to stop the bleeding.
그림3, Once the wound has stopped bleeding, apply an antibacterial ointment to coat and protect the wound.
그림4, Cover it with a bandage that will not stick to the wound.

치료 순서
(1) 세척
(2) 지혈
(3) 드레싱(Dressing)
(4) 테이핑

Step 1, Cleaning
The aim of wound cleaning is to remove devitalized tissue, foreign debris, and contaminants which can harbor microorganism or provide nutrients for their growth. However cleaning can creat tissue trauma. Cleaning agents should have balance between their antibacterial properties and cellular cytotoxicity to fibrablasts and white blood cells.
The best way to clean a wound is with cool water. Using a isotonic saline, a mixture of sterile water and salt, is less painful. Isotonic water is made with 1 or 2 teaspoon salt in 1 liter sterile water. Wash from the center out. Soap and a soft washcloth may be used to clean the skin around the wound. Do not use stronger cleansing solution such as hydrogen peroxide, mercurochrome, iodine, alcohol or an antiseptic bercuse they are toxic to all cells including white cells and fibroblasts. Cleaning divices include sponge, bulb syringe, and "needle and syringe". A variety of needle and syringe combination achieve ranges of irrigation pressure. The optimum pressure for wound cleaning is between 5 and 15 psi. The larger syringe, the less the force. With a 19G needle, 6-cc, 12-cc, and 35-cc syringe will produce pressure or 30, 20, and 8 psi, respectively. A 12-cc syringe with 22G needle produces 13 psi.
The purpose of debridement is to reduce the bioburden to prevent wound infection. If necrotic tissue is not removed, it impedes healing by protein loss and infection. Removing necrotic tissue restores circulation and allows adeqate oxygen delivery to the wound site. Bacteria competes with healing cells for oxygen and nutrients. Debriding too much tissue can destroy wound bed. Some wounds such as heels or toes should not be debrided due to poor blood supply.
For a minor puncture, use a stream of water to rinse the puncture wound. Minor bleeding helps clean out wounds so that you may allow to bleed for the first few seconds.
(그림 5, (A) You can hold the wound under running water or pour water from a cup over the wound.(B) Stream of water ejected from a needle tip of syringe. (C) The needl may be removed for safety).

Step 2, Bleeding control
If there is bleeding, apply firm pressure on the cut with a clean cloth, tissue or piece of gauze. If the blood soaks through the gauze or cloth you are holding over the cut, do not take it off. If bleeding persists after 10 minutes, just put more gauze on top over a wider area of what you already have in place and apply more pressure. Changing the gauzes interrupts aggregation of platelets and delays blood clot formation. When bleeding stops, apply pressure bandage with such as roller gauze. On a protruding bone, a skull fracture, or an embeded object, direct pressure should not be applied.
Wounds on the face, head or mouth will sometimes bleed a lot because these areas are rich in blood vessels. With scalp hemorrhage, compression must be used to stop the bleeding. Scalp laceration can be a source of significant bleeding because of the rich vasculature of this tissue. Ultimately, closure of the wound is the definitive treatment for bleeding.
If an artery is completerly severed, artery draws back into the tissue and constricts and slows bleeding. Partially severed arteries such as in amputations are associated with greater blood loss. When an artery is severed, the connective tissue fibers around the vessel contract and pull the artery open. This results is more hemorrhage than in other places.
==[Morris J, Biga L, Yeatman J. Treatment of bleeding laceration. Available URL from:http://www.mc.vanderbilt.edu/lifeflight/web/protocol/pdf/5n.pdf#search='scalp%20vessel%20AND%20bleeding']
==[Wesley Norman. Tha anatomy lesson-HEAD AND NECK. Available URL from:http://mywebpages.comcast.net/wnor/lesson1.htm]

Step 3, Dressing
Dressing is a protective covering for a wound, which is accomplished with an adhesive strip,  sterile gauze, or Band-Aid.
A small superficial wound may not be covered, unless that will get dirty or be irritated by clothing should be covered. In the area easily wet such as a hand or foot, a superficial wound can be covered by an adhesive strip without gauze underneath, and is left for 2-3 days until the adhesive strip is taken off.
Certain wounds, such as abrasions that cover a large area of the body, should be kept moist and clean to help reduce scarring and speed healing. Bandages used for this purpose are called occlusive or semiocclusive bandages.

Antibiotic ointments (such as Bacitracin) help healing by keeping out infection and by keeping the wound moist. SInce there is a risk of selecting out resistant strain of bacteria, antibiotics that are used to treat infections systemically (such as gentamicin) should not be used in a topical form on wound.
Scabs protect wounds from dirt. It's best to leave them alone and not pick at them. The ointment also keeps a heavy scab from forming and may reduce the size of a scar.
 
Step 4, Taping or Bandage
Bandage is a material used to hold a derssing in place. It is also used for applying pressure or reducing swelling. Leave toes and fingers exposed if possible. Those are for checking blood circulation.

Bandage is a strip of cloth or other material used to cover a wound. Dressing is covering, protective or supportive material that is applied to an injury or wound.

Taping can be used for injury care or skin protection.
   - Retention of wound dressings
   - Stabilization of compression bandages that control external and internal hemorrhaging
   - Support of recent injuries to prevent additional insult that might result from the activities of the athlete
   - Stabilization

When removing adhesive tapes, manually peel the skin from the tape, not the tape from the skin. Or use of tape scissors or cutters.
[Sport Medicine Club. Bandaging and Taping. Available URL from:http://www.geocities.com/hideciao2000/at_taping.html]

You need a tetanus shot if you have not had a tetanus shot within the last 10 years. A tetanus vaccine is generally recommended every 10 years.  If your wound is deep or dirty and your last shot was more than five years ago, your doctor may recommend a tetanus shot booster. Get the booster within 48 hours of the injury.
Watch for signs of infection. See your doctor if the wound isn't healing or you notice any redness, drainage, warmth or swelling.

Amputation
Massive hemorrhage can occur but most often the bleeding will control itself with a spontaneous retraction of major vessels and ordinary pressure applied to the stump. Cover stump with damp sterile dressing and elastic wrap.  Apply tight enough to apply uniform, reasonable pressure across entire stump. If direct pressure does not control bleeding, a tourniquet may be used. Place amputated parts in plastic bag, if available. Place bag in larger bag or container containing ice and water - cooling slows the chemical processes and will increase viability in excess of four hours. Do NOT place amputated part directly on ice.

Closing the wound
You can close small cuts yourself with special tape, called butterfly tape, or special adhesive strips, such as Steri-Strips. Get stitches for deep wounds. A wound that cuts deeply through the skin or is gaping or jagged-edged and has fat or muscle protruding usually requires stitches. Proper closure within a few hours minimizes the risk of infection.

Adhesive strips
Adhesive skin strips alone might be useful for skin approximation or in combination with sutures. However, certain areas are not amenable to this technique of skin closure because of potential motion such as around the fingers or mouth and in hair-bearing areas including the beard. It should be remembered that children may not leave this type of closure alone but may disturb the adhesive strips with the resultant reopening on the wound. When these adhesive strips are utilized, an additional dressing over the site is recommended.
After the bleeding stpos, a butterfly bandages should be applied to hold the wound shut. Do not remove the bandage for 5 days. The "golden" period to stitch a wound is within 8 hours of the injury.

그림:http://familydoctor.org/041.xml

Suture
Use as many stitches as necessary to approximate the wound edges. Every stitch becomes a foreign body and becomes the source of an additional wound. Use what is required and no more.

Suture Size
Sized according to diameter with "0" as reference size.
Numbers alone indicate progressively larger sutures ("1", "2", etc).
Numbers followed by a "0" indicate progressively smaller sutures "2-0", "4-0", etc).
Smaller <-------------------------------> Larger
...."3-0"...."2-0"...."1-0"...."0"...."1"...."2"...."3"....

Taking care of stitches
an area that has been stitched can be washed  in one to three days. Washing off dirt and the crust that may form around the stitches helps reduce scarring. If the wound drains clear yellow fluid, you may need to cover it. Be sure to dry it well after washing.
A small amount of antibiotic ointment prevents infection and keeps a heavy scab from forming and may reduce the size of a scar.

Stitch removal
Stitches are usually removed in 3 to 14 days, depending on where the cut is located. Areas that move, such as over or around the joints, require more time to heal. The stitches are left in place varying times depending on their location. Healing is usually rapid in the head and neck region and slowest in the distal lower extremities. Usually, sutures may be removed from the face on the fourth or fifth day after repair, from the trunk on the seventh or eighth day and from the leg on the ninth or tenth day.

Patients should be advised to return for a wound check should there be unexpected swelling, erythema, or drainage. A stitch may need to be removed so that adequate drainage can be assured if there is a collection beneath the skin surface.

Patients who have compromised healing (poor nutrition, diabetes, on steriod medication, etc.) require their stitches to remain for longer time periods.

Stitches are usually removed in 3 to 14 days, depending on where the cut is located. Areas that move, such as over or around the joints, require more time to heal. You can usually wash an area that has been stitched in one to three days. Washing off dirt and the crust that may form around the stitches helps reduce scarring. If the wound drains clear yellow fluid, you may need to cover it.

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Skin tear is a separation of the epidermis and the dermis as a result of friction. Skin tears that occur on the back and buttocks are commonly mistaken for stage II pressure ulcers. Treatments include petratum ointment and nonadherant dressings. Use paper tape or nonadherent dressings on frail skin.Remove tapes gently to prevent skin injury.

Blister of Heels
Should a large, but unopened blister be lanced? There is debate on that point - some argue that doing so opens you to infection. But I have found that lancing the blister with a sterile needle or scalpel blade reduces the risk of completely tearing the "roof" of the blister and exposing the raw skin beneath. To lance a blister, clean it thoroughly; pierce the blister from the side, and drain. Cover with a generous amount of Neosporin (or similar antibiotic cream), and bandage.
A torn blister can be a serious problem. Clean the area with Betadine or soap and water, and let dry. Spread antibiotic cream over the broken skin, and re-bandage with an adhesive bandage, or non-stick pads and tape or moleskin.
Better-fitting boots and blister-preventing socks should be used to prevent blisters.

Doug Gantenbein. Treating Blisters On and Off the Trail. In:Great Outdoos.com. Available from URL:http://www.greatoutdoors.com/published/camp/healthfitness/anounceofprevention/

Crack on the heel and hands
Apply softening cream and wear socks and gloves while sleeping. When a crack gets deep and painful, put a good dab of zinc oxide on and cover with a bandaid. Use something to rub the extra tough callused skin off on places like my heels during or after a cleansiing.

First aid kit
The following items are basic supplies.

Adhesive bandages (Band-Aid or similar brand); assorted sizes
Sterile gauze pads and adhesive tape
Sterile cotton balls
Antibiotic ointment, such as bacitracin, polysporin, or mupirocin
Sterile eyewash, such as contact lens saline solution
Tweezers, to remove ticks and small splinters

American society of plastic surgeon. Everyday Wounds Suturing Principles. Available from URL:http://www.plasticsurgery.org/medical_professionals/publications/everyday-wounds-ch09-suturing-principles.cfm?RenderForPrint=1
Medlineplus. Wounds. Available from URL:http://www.nlm.nih.gov/medlineplus/wounds.html
Mayo Clinic Medical Services. Cuts and scrapes: First aid. Available from URL:http://www.mayoclinic.com/health/first-aid-cuts/FA00042