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Classification and management of acute wounds
Basic skills
Classification and management of acute wounds
Principal steps in the management of an acute wound Steps
Core issues and activities
Assessment
Accurate history: magnitude of trauma, contamination Diagnosis and stratification Associated injuries: neurovascular, musculoskeletal, visceral Need for referral/multidisciplinary approach/triage Prophylaxis: antibiotic, tetanus Analgesia/anaesthesia Exploration, toilet and debridement Haemostasis Closure: when, how, where, which first? Drainage Referral/multidisciplinary approach? Dressings Removal of sutures/splints Surveillance for complications Physiotherapy and rehabilitation
Senthil Kumar David John Leaper
Abstract
Preparation
Acute wounds are aetiologically and pathophysiologically diverse, features that impact on their natural history and guide management. Wound healing is a dynamic process and requires appropriate shifts in perspective in the clinical management of the wound, and is reflected in the terminology and classification systems which address different domains of the wound. Wound management begins with assessment and classification and may continue well after the wound has clinically healed. Before a wound can be closed, it may need to be prepared by toilet and debridement and protected against infection by appropriate prophylactic measures. Judgement and surgical skill are necessary to decide whether a wound is best allowed to heal by first, second or third intention. Wounds may be directly closed by approximation of edges or by transfer of tissues.
Definitive treatment
After-care
Table 1
Keywords acute wounds; general surgery; wound classification; wound
Design: the diversity of wounds and the potential for continual change makes it difficult to design a single, all-encompassing classification system that incorporates all attributes of a wound at all times. Hence, the descriptors used in classifications often focus on one or a few of the aspects of the wound relevant to the clinical context. The different systems of classification are complementary, thus a comprehensive description of a given wound requires the use of descriptors from more than one system.
closure; wound management
Wounds have diverse causes with varied anatomical associations that influence their morphology, natural history and management. Wound healing is a dynamic process and the clinical perspective changes depending on the phase of healing. Management of a wound consists of several interrelated steps influenced by a number of factors that extend beyond the immediate confines of the wound and the operating theatre. The general principles are outlined in Table 1, but wounds often require additional, individual treatment.
Types Aetiological and morphological: the mode and pattern of injury are the focus. Acute wounds usually follow trauma or inflammation and usually heal within six weeks. Chronic wounds (in addition to failing to heal after six weeks) have characteristic pathological associations that inhibit or delay healing. The USA National Research Council classification (Table 3) segregates wounds according to the degree of contamination, which has implications for management and predicts infection risk.
Wound classification systems (Table 2) Aims: wound classification systems provide frameworks that: • aid diagnosis and stratification • ensure uniformity of documentation • offer prognostic information • guide management.
Wound complexity provides a wider perspective of the clinical context of the wound and incorporates useful clinical information with implications for management. A simple wound involves skin and subcutaneous tissue, without significant tissue loss and without any associated complications. A complex wound is associated with significant tissue loss or devitalization; communicates with viscera (e.g. fistula), body cavities (e.g. laparostomy), joints or prosthesis; or has associated injuries or paths leading to vital structures. A complicated wound has suffered a secondary complication such as an infection, ischaemia (flap necrosis), haematoma or compartment syndrome.
Senthil Kumar FRCSC(Ed) is a Clinical Research Fellow in Surgery at University Hospital of North Tees, Stockton-on-Tees, UK. Conflicts of interest: none declared. David John Leaper FRCS FRCS(Ed) is Emeritus Professor of Surgery at Newcastle upon Tyne University, Newcastle, UK, and Visiting Professor of Surgery, Wound Healing Research Unit, Department of Surgery, Cardiff University, Cardiff, UK. Conflicts of interest: none declared.
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© 2007 Elsevier Ltd. All rights reserved.
Basic skills
Synopsis of wound classification systems for acute wounds Aetiological
Morphological
Contamination
Complexity
Surgical Penetrating trauma Stab Projectile injury Bite/envenomation Blunt trauma Avulsion/traction Crush injury Burns Thermal Electrical Irradiation Frost-bite
Abrasion Incision Superficial Deep Laceration Superficial Deep Degloving injury Ulceration Superficial Deep
Clean Implant Non-implant Clean-contaminated Contaminated Dirty-infected
Simple Complex Open fracture Laparostomy Complicated Wound infection Gas gangrene Flap necrosis
Table 2
Grading and scoring systems exist for specific conditions (e.g. pressure ulcers, diabetic ulcers), but are beyond the scope of this review. Two systems that are relevant to the acute surgical wound when comparing outcomes in audit and for risk prediction are discussed below. The ASEPSIS scoring system assigns empirical scores to different dimensions of the wound (additional treatment, serous discharge, erythema, purulent discharge, separation of deep tissues, isolation of bacteria, duration of hospital stay). The wound is serially assessed and scored over five days. The individual scores are summated to give a single numerical value which is used to grade the wound. A summated score of >20 defines an infection.
The National Nosocomial Infection Surveillance system score was adopted by the Centers for Disease Control and Prevention (Atlanta, USA). The score assigns one point each for: • a non-clean (clean-contaminated, contaminated and dirty) wound • American Society of Anesthesiology physical status of 3 or more • an operative time more than the seventy-fifth centile for similar procedures. The higher the score, the greater the risk of infection. This score is a risk stratification score used primarily to adjust for case-mix and allow for comparing groups of patients across institutions. However, it underlines the fact that, in addition to contamination,
USA National Research Council system of wound classification Wound classification
Criteria
Examples
Clean
An incised wound through uninflamed tissue created at elective surgery and closed primarily. Only a closed system of drainage employed Oropharyngeal, tracheobronchial, gastrointestinal, biliopancreatic, genitourinary tracts are not entered No breach in aseptic technique
Clean-contaminated
Wound (that is otherwise clean) created at emergency surgery Reoperation via clean incision within 7 days Elective controlled entry into visceral tracts with minimum spillage of contents Minor break in aseptic technique Wounds left open; fresh accidental wounds; penetrating trauma < 4 hours old Operations with gross spillage of gastrointestinal contents; major breaks in sterile technique Presence of pus Preoperative perforation of oropharyngeal, tracheobronchial, gastrointestinal, biliopancreatic, genitourinary tracts Penetrating trauma > 4 hours old
Non-implant Mastectomy Herniorrhaphy Implant Hip replacement Hernioplasty Cholecystectomy Elective lung resection
Contaminated
Dirty
Stab wound Non-perforated appendicitis Laparotomy wound for sigmoid diverticular perforation
Table 3
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© 2007 Elsevier Ltd. All rights reserved.
Basic skills
operative factors and comorbid conditions are important factors in wound outcomes.
The choice of antibiotic varies depending on the site of trauma or surgery, which determines the type of organisms encountered. In general, an agent with a broad spectrum (e.g. secondgeneration cephalosporin) is recommended, and metronidazole is added if anaerobic cover is necessary. In wounds with significant contamination, prophylaxis against gas gangrene must be instituted (e.g. benzyl penicillin 1.2 g (i.v.) 4–6 hourly for 48 hours).
Management Preparation A wound represents a violation of natural defence barriers and encourages invasion by micro-organisms. Many factors related to the host, the wound and the micro-organism interact soon after the wound is created and influence the occurrence of wound infection. Chief factors in otherwise immunocompetent individuals are the size and virulence of the inoculum, the presence of foreign body, and tissue hypoxia. One or more of these factors can be manipulated in most clinical settings and form the basis of infection prevention. Antibiotics (see below) have a role in reducing wound infections, but they do not replace the need for aseptic technique, atraumatic handling of tissue and good perioperative wound care.
Adjuncts to antibiotic prophylaxis: there are two adjuncts to antibiotic prophylaxis that may further reduce the incidence of wound infections. Perioperative oxygen supplementation – oxygen tension in the wound plays a vital role in local defence mechanisms. Perioperative oxygen supplementation reduces wound infection rates after colorectal surgery. Maintenence of perioperative normothermia has immuno logical and haemorrheological advantages that augment the capacity of the wound to fight infection; it also improves the oxygen tension of the wound. Perioperative systemic warming and local warming reduce wound infection rates after colorectal surgery, as well as breast, hernia and varicose vein surgery.
Antibiotic prophylaxis is needed for clean-contaminated and contaminated wounds. The use of antibiotics in dirty wounds must be prolonged and is essentially therapeutic. The role of antibiotic prophylaxis in clean wounds is controversial and subject to a wide variation in practice. The situations described below may warrant antibiotic prophylaxis in clean wounds. When the risk of infection is high • Observed rates of infection for a particular procedure in a given clinical environment is >4% (arbitrary cut-off point). • National Nosocomial Infection Surveillance score of >1. • Presence of other high-risk factors (e.g. immunosuppression, poorly controlled diabetes, morbid obesity, remote infection, reoperation, prior local irradiation, severe malnutrition, extremes of age). When the consequences of an infection are potentially disastrous • Involves an implant (vascular graft, joint prosthesis). • Involves incised bone leading to a cavity (sternotomy, craniotomy). • Presence of a prosthetic heart valve.
Tetanus prophylaxis (Table 4): a decision regarding tetanus prophylaxis must be made in every patient with an injury. Tetanus is rare in clean wounds, but is more likely in wounds: • contaminated with soil or manure • with extensive devitalized tissue (especially muscle) • in the lower limbs, axilla • caused by bites • that are punctured deeply. Wound exploration, wound toilet and debridement: acute post-traumatic wounds are often contaminated when they present. They must be prepared by a combination of exploration, wound toilet and debridement before a definitive treatment plan can be formulated. Wound exploration – with the exception of minor superficial wounds, most post-traumatic wounds must be explored to assess the anatomical extent of injury and to detect associated injur ies to underlying neurovascular structures, tendons, joints and
Guidelines for tetanus prophylaxis Immunization status
Type of wound Low risk
High risk
Last of 3-dose course or a reinforcing dose given < 10 years ago
Further immunization is not needed
Last of 3-dose course or reinforcing dose given > 10 years ago
A single reinforcing dose of adsorbed vaccine (0.5 ml i.m./deep subcutaneous) Full course of adsorbed vaccine
None if moderate risk Give a dose of tetanus immunoglobulin (250 IU in 1 ml i.m.) if particularly high risk A single reinforcing dose of adsorbed tetanus vaccine + Human tetanus immunoglobulin in a different site Full course of adsorbed vaccine + Human tetanus immunoglobulin in a different site
Not immunized/status unknown
Table 4
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© 2007 Elsevier Ltd. All rights reserved.
Basic skills
bones. This is particularly important in penetrating (especially projectile) injuries because significant damage to deeper structures may be masked by an apparently small surface wound. The second purpose of exploration is to locate and remove foreign bodies. If glass, gravel or metallic foreign bodies are suspected, radiological expertise with surface markers in place before and after exploration may be useful. However, many organic foreign bodies (e.g. wooden splinters) and many synthetic materials (e.g. plastic) may be missed on a radiograph. Even if no foreign body is suspected, exploration may be necessary for better access for debridement of potentially devitalized tissue and for haemostasis. Wound toilet is the cleansing of the wound with water, saline or antiseptics (e.g. chlorhexidine, cetrimide, povidone iodine). Several litres of warmed isotonic fluid may be needed for large wounds. A soft brush or sponge may be used to gently scrub the wound to clear particulate matter. Wound toilet should be performed at the first available opportunity because bacterial counts increase with time. Debridement is the removal of foreign matter, necrotic and devitalized tissue from the wound. Debridement aims to achieve a clean, raw area that is well perfused and has a low bacterial count. Surgical and mechanical debridement are commonly used in acute wounds, whereas autolytic, enzymatic and biological methods are more relevant in wounds presenting late or in chronic wounds (Table 5). Surgical debridement is the most rapid method and, in posttraumatic wounds, involves excising subcutaneous tissue and muscle until bleeding from the cut edges is satisfactory. Free-lying bone denuded of periosteum must be removed. The skin must not be undermined because the blood supply may be compromised.
of wound edges, heals without complications at the first instance. Advantages of primary closure are good cosmetic effect and shorter time to clinical healing. Primary closure is the preferred method of closure for clean wounds with minimal tissue loss. Primary closure should ideally be performed within 6–8 hours of trauma. However, wounds in vascular areas (e.g. face, scalp) may be closed up to 24 hours after trauma. Secondary closure (healing by secondary or second intention) occurs when a wound which is left open heals largely by formation of granulation tissue and contraction. Wounds that are candidates for secondary closure include those with significant tissue loss precluding tension-free approximation of edges, de vitalized edges, ulcerations, and abscess cavities. There is evidence that the wound contraction that occurs with secondary healing gives a better cosmetic result than early skin grafting in certain situations (e.g. healing of fasciotomy wounds). Tertiary closure (healing by tertiary or third intention) is the delayed closure of a wound after a variable period of time for which it has been left open. In general, tertiary closure is applied to wounds that are grossly contaminated or present late, but do not have significant tissue loss. Wounds that need to be considered for delayed primary closure include those contaminated by soil, manure or faeces, caused by animal bites or projectiles. Such wounds need a thorough wound toilet, exploration and debridement, after which they are observed for 3–7 days before closure. The term ‘secondary suture’ is usually applied when a wound is left open for >10 days, allowing the formation of clean granulation tissue before mechanical closure can be undertaken. Modes of closure: there are two types Direct closure is the closure of wound by approximation of the wound edges. Wound closure includes ensuring a clean wound with satisfactory vascularity and haemostasis, and apposition without tension, inversion or dead space. Tension in the wound may be reduced by the use of subcutaneous sutures or undermining of the wound edges. Eversion
Wound closure Types of healing: the three types of clinical wound healing depend on the timing and method by which wound closure is achieved. Primary closure (healing by primary or first intention) refers to a wound which, when mechanically closed by approximation
Debridement Type
Description
Surgical
Excision of devitalized tissue and particulate matter using sharp instruments. Useful in the following wound types: posttraumatic, infected or necrotic postoperative, chronic. Forced irrigation of saline from a 50 ml syringe through an 18-G catheter applies about 15 pounds per square inch of pressure to remove loose necrotic tissue. An alternative is the wet-to-dry dressing method, in which a moist gauze dressing is allowed to dry on the wound. Removal without wetting results in removal of fibrin and slough. This method as often insufficient, can be painful and may damage underlying epithelium. Topical negative pressure (vacuum-assisted closure) removes exudate and necrotic tissue, and is used in a variety of wounds to reduce the size of the defect (e.g. laparostomies, wounds after pilonidal sinus excision). An occlusive dressing applied to the wound allows wound proteases to liquefy the necrotic tissues, which may be washed away at dressing changes. Collagenase liquefies collagen and elastin (but not fibrin); papain with urea degrades fibrin and collagen. Enzymatic debriding agents should be applied only on non-viable areas of the wound. They are expensive and have a limited role in selected chronic wounds. Medical-grade larvae of Lucilia sericata are necrophagous and are useful in selected chronic wounds.
Mechanical
Autolytic Enzymatic
Biological Table 5
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© 2007 Elsevier Ltd. All rights reserved.
Basic skills
can be achieved by using vertical or horizontal mattress sutures. Dead space in clean wounds may be obliterated by deep subcutaneous sutures. However, overzealous closure tends to leave a large volume of suture material in the depths and increases the risk of infection. Sutures, staples, skin tapes and cyanoacrylate glue are commonly used in direct closure of wounds. Subcuticular sutures produce a better cosmetic result than percutaneous sutures and are suitable in most postoperative wounds. In post-traumatic wounds, interrupted percutaneous sutures are preferred because they accommodate wound oedema and allow efflux of wound fluid. The smallest-diameter suture necessary to provide wound strength should be chosen. In the face, a 5/0 or 6/0 suture is usually used; 3/0 or 4/0 sutures will suffice in most other areas. Synthetic monofilament sutures are the least reactive and are preferred to silk and catgut. Sutures should be removed in: • 48 hours in the eyelid • 4 days in the face • 7–10 days in the trunk • 10–12 days in the upper limb • 10–14 days in the lower limb. Staples are inert, may be used in most straight lacerations and are particularly useful if quick closure of skin is necessary. They should be avoided in the hands, face and if imaging (CT, MRI) of the area is planned. Skin tapes do not leave scars and are suitable for superficial wounds under no tension and for additional support for the wound after suture removal. Another useful application is in avulsions with doubtful skin viability; for example, a pretibial injury that leaves a distal triangulated flap, where suturing is contraindicated but the flap needs to be replaced back on its bed. Transplanted closure is the term used if non-native tissue (e.g. skin grafts, skin flaps) is employed to achieve closure. Skin grafting can provide wound cover in large raw areas that cannot be closed by direct closure, for example: • wounds following avulsion injuries (especially injuries that cause a distal flap in the leg)
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• raw areas resulting after wound excision for full-thickness burns. Split-skin grafts have a superior take rate, but poorer cosmetic effect when compared to full-thickness grafts. Skin should not be grafted over bare bone, tendon, cartilage, major vessels or an irradiated area. Local or distant flaps are preferred to skin grafting if: • the wound bed is not very vascular • bare tendons or nerves are exposed • the wound is over a bony prominence • radiotherapy or repeat surgery is contemplated • better cosmetic effect is required. Wound drainage: blood and wound fluid collecting within or under a wound may give rise to: • pressure effects (vascular compromise, airway compromise, pressure on nerves, compartment syndromes) • infectious complications (infected seroma, infected haematoma, abscess) • unsightly swellings that may or may not be symptomatic. Wound drainage is usually employed if the risk of a fluid collection is estimated to be high or unacceptable because of anatom ical factors (which lead to pressure effects) or if the volume of collection is anticipated to be high. A closed system of drainage should be employed because it is aseptic. Open systems such as wicks and corrugated drains covered with gauze swabs are not ideal for clean wounds (though they may have advantages in selected contaminated wounds). Drains may fail because of blocked or exposed holes, kinking, or due to thick effluent or coagulum. Suction may make the drains more efficient, but is contraindicated if the drain is close to major vessels or bowel. There are no evidence-based guidelines for the duration of drainage because it depends on the site and complexity of the wound, and the purpose it was employed for. The volume and quality of the effluent should inform decision making. Leaving the drain for too long may act as a foreign body, irritating the raw area and be a potential nidus for infection. ◆
47
© 2007 Elsevier Ltd. All rights reserved.
Classification and management of acute wounds
Principal steps in the management of an acute wound Steps
Core issues and activities
Assessment
Accurate history: magnitude of trauma, contamination Diagnosis and stratification Associated injuries: neurovascular, musculoskeletal, visceral Need for referral/multidisciplinary approach/triage Prophylaxis: antibiotic, tetanus Analgesia/anaesthesia Exploration, toilet and debridement Haemostasis Closure: when, how, where, which first? Drainage Referral/multidisciplinary approach? Dressings Removal of sutures/splints Surveillance for complications Physiotherapy and rehabilitation
Senthil Kumar David John Leaper
Abstract
Preparation
Acute wounds are aetiologically and pathophysiologically diverse, features that impact on their natural history and guide management. Wound healing is a dynamic process and requires appropriate shifts in perspective in the clinical management of the wound, and is reflected in the terminology and classification systems which address different domains of the wound. Wound management begins with assessment and classification and may continue well after the wound has clinically healed. Before a wound can be closed, it may need to be prepared by toilet and debridement and protected against infection by appropriate prophylactic measures. Judgement and surgical skill are necessary to decide whether a wound is best allowed to heal by first, second or third intention. Wounds may be directly closed by approximation of edges or by transfer of tissues.
Definitive treatment
After-care
Table 1
Keywords acute wounds; general surgery; wound classification; wound
Design: the diversity of wounds and the potential for continual change makes it difficult to design a single, all-encompassing classification system that incorporates all attributes of a wound at all times. Hence, the descriptors used in classifications often focus on one or a few of the aspects of the wound relevant to the clinical context. The different systems of classification are complementary, thus a comprehensive description of a given wound requires the use of descriptors from more than one system.
closure; wound management
Wounds have diverse causes with varied anatomical associations that influence their morphology, natural history and management. Wound healing is a dynamic process and the clinical perspective changes depending on the phase of healing. Management of a wound consists of several interrelated steps influenced by a number of factors that extend beyond the immediate confines of the wound and the operating theatre. The general principles are outlined in Table 1, but wounds often require additional, individual treatment.
Types Aetiological and morphological: the mode and pattern of injury are the focus. Acute wounds usually follow trauma or inflammation and usually heal within six weeks. Chronic wounds (in addition to failing to heal after six weeks) have characteristic pathological associations that inhibit or delay healing. The USA National Research Council classification (Table 3) segregates wounds according to the degree of contamination, which has implications for management and predicts infection risk.
Wound classification systems (Table 2) Aims: wound classification systems provide frameworks that: • aid diagnosis and stratification • ensure uniformity of documentation • offer prognostic information • guide management.
Wound complexity provides a wider perspective of the clinical context of the wound and incorporates useful clinical information with implications for management. A simple wound involves skin and subcutaneous tissue, without significant tissue loss and without any associated complications. A complex wound is associated with significant tissue loss or devitalization; communicates with viscera (e.g. fistula), body cavities (e.g. laparostomy), joints or prosthesis; or has associated injuries or paths leading to vital structures. A complicated wound has suffered a secondary complication such as an infection, ischaemia (flap necrosis), haematoma or compartment syndrome.
Senthil Kumar FRCSC(Ed) is a Clinical Research Fellow in Surgery at University Hospital of North Tees, Stockton-on-Tees, UK. Conflicts of interest: none declared. David John Leaper FRCS FRCS(Ed) is Emeritus Professor of Surgery at Newcastle upon Tyne University, Newcastle, UK, and Visiting Professor of Surgery, Wound Healing Research Unit, Department of Surgery, Cardiff University, Cardiff, UK. Conflicts of interest: none declared.
SURGERY 26:2
43
© 2007 Elsevier Ltd. All rights reserved.
Basic skills
Synopsis of wound classification systems for acute wounds Aetiological
Morphological
Contamination
Complexity
Surgical Penetrating trauma Stab Projectile injury Bite/envenomation Blunt trauma Avulsion/traction Crush injury Burns Thermal Electrical Irradiation Frost-bite
Abrasion Incision Superficial Deep Laceration Superficial Deep Degloving injury Ulceration Superficial Deep
Clean Implant Non-implant Clean-contaminated Contaminated Dirty-infected
Simple Complex Open fracture Laparostomy Complicated Wound infection Gas gangrene Flap necrosis
Table 2
Grading and scoring systems exist for specific conditions (e.g. pressure ulcers, diabetic ulcers), but are beyond the scope of this review. Two systems that are relevant to the acute surgical wound when comparing outcomes in audit and for risk prediction are discussed below. The ASEPSIS scoring system assigns empirical scores to different dimensions of the wound (additional treatment, serous discharge, erythema, purulent discharge, separation of deep tissues, isolation of bacteria, duration of hospital stay). The wound is serially assessed and scored over five days. The individual scores are summated to give a single numerical value which is used to grade the wound. A summated score of >20 defines an infection.
The National Nosocomial Infection Surveillance system score was adopted by the Centers for Disease Control and Prevention (Atlanta, USA). The score assigns one point each for: • a non-clean (clean-contaminated, contaminated and dirty) wound • American Society of Anesthesiology physical status of 3 or more • an operative time more than the seventy-fifth centile for similar procedures. The higher the score, the greater the risk of infection. This score is a risk stratification score used primarily to adjust for case-mix and allow for comparing groups of patients across institutions. However, it underlines the fact that, in addition to contamination,
USA National Research Council system of wound classification Wound classification
Criteria
Examples
Clean
An incised wound through uninflamed tissue created at elective surgery and closed primarily. Only a closed system of drainage employed Oropharyngeal, tracheobronchial, gastrointestinal, biliopancreatic, genitourinary tracts are not entered No breach in aseptic technique
Clean-contaminated
Wound (that is otherwise clean) created at emergency surgery Reoperation via clean incision within 7 days Elective controlled entry into visceral tracts with minimum spillage of contents Minor break in aseptic technique Wounds left open; fresh accidental wounds; penetrating trauma < 4 hours old Operations with gross spillage of gastrointestinal contents; major breaks in sterile technique Presence of pus Preoperative perforation of oropharyngeal, tracheobronchial, gastrointestinal, biliopancreatic, genitourinary tracts Penetrating trauma > 4 hours old
Non-implant Mastectomy Herniorrhaphy Implant Hip replacement Hernioplasty Cholecystectomy Elective lung resection
Contaminated
Dirty
Stab wound Non-perforated appendicitis Laparotomy wound for sigmoid diverticular perforation
Table 3
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© 2007 Elsevier Ltd. All rights reserved.
Basic skills
operative factors and comorbid conditions are important factors in wound outcomes.
The choice of antibiotic varies depending on the site of trauma or surgery, which determines the type of organisms encountered. In general, an agent with a broad spectrum (e.g. secondgeneration cephalosporin) is recommended, and metronidazole is added if anaerobic cover is necessary. In wounds with significant contamination, prophylaxis against gas gangrene must be instituted (e.g. benzyl penicillin 1.2 g (i.v.) 4–6 hourly for 48 hours).
Management Preparation A wound represents a violation of natural defence barriers and encourages invasion by micro-organisms. Many factors related to the host, the wound and the micro-organism interact soon after the wound is created and influence the occurrence of wound infection. Chief factors in otherwise immunocompetent individuals are the size and virulence of the inoculum, the presence of foreign body, and tissue hypoxia. One or more of these factors can be manipulated in most clinical settings and form the basis of infection prevention. Antibiotics (see below) have a role in reducing wound infections, but they do not replace the need for aseptic technique, atraumatic handling of tissue and good perioperative wound care.
Adjuncts to antibiotic prophylaxis: there are two adjuncts to antibiotic prophylaxis that may further reduce the incidence of wound infections. Perioperative oxygen supplementation – oxygen tension in the wound plays a vital role in local defence mechanisms. Perioperative oxygen supplementation reduces wound infection rates after colorectal surgery. Maintenence of perioperative normothermia has immuno logical and haemorrheological advantages that augment the capacity of the wound to fight infection; it also improves the oxygen tension of the wound. Perioperative systemic warming and local warming reduce wound infection rates after colorectal surgery, as well as breast, hernia and varicose vein surgery.
Antibiotic prophylaxis is needed for clean-contaminated and contaminated wounds. The use of antibiotics in dirty wounds must be prolonged and is essentially therapeutic. The role of antibiotic prophylaxis in clean wounds is controversial and subject to a wide variation in practice. The situations described below may warrant antibiotic prophylaxis in clean wounds. When the risk of infection is high • Observed rates of infection for a particular procedure in a given clinical environment is >4% (arbitrary cut-off point). • National Nosocomial Infection Surveillance score of >1. • Presence of other high-risk factors (e.g. immunosuppression, poorly controlled diabetes, morbid obesity, remote infection, reoperation, prior local irradiation, severe malnutrition, extremes of age). When the consequences of an infection are potentially disastrous • Involves an implant (vascular graft, joint prosthesis). • Involves incised bone leading to a cavity (sternotomy, craniotomy). • Presence of a prosthetic heart valve.
Tetanus prophylaxis (Table 4): a decision regarding tetanus prophylaxis must be made in every patient with an injury. Tetanus is rare in clean wounds, but is more likely in wounds: • contaminated with soil or manure • with extensive devitalized tissue (especially muscle) • in the lower limbs, axilla • caused by bites • that are punctured deeply. Wound exploration, wound toilet and debridement: acute post-traumatic wounds are often contaminated when they present. They must be prepared by a combination of exploration, wound toilet and debridement before a definitive treatment plan can be formulated. Wound exploration – with the exception of minor superficial wounds, most post-traumatic wounds must be explored to assess the anatomical extent of injury and to detect associated injur ies to underlying neurovascular structures, tendons, joints and
Guidelines for tetanus prophylaxis Immunization status
Type of wound Low risk
High risk
Last of 3-dose course or a reinforcing dose given < 10 years ago
Further immunization is not needed
Last of 3-dose course or reinforcing dose given > 10 years ago
A single reinforcing dose of adsorbed vaccine (0.5 ml i.m./deep subcutaneous) Full course of adsorbed vaccine
None if moderate risk Give a dose of tetanus immunoglobulin (250 IU in 1 ml i.m.) if particularly high risk A single reinforcing dose of adsorbed tetanus vaccine + Human tetanus immunoglobulin in a different site Full course of adsorbed vaccine + Human tetanus immunoglobulin in a different site
Not immunized/status unknown
Table 4
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© 2007 Elsevier Ltd. All rights reserved.
Basic skills
bones. This is particularly important in penetrating (especially projectile) injuries because significant damage to deeper structures may be masked by an apparently small surface wound. The second purpose of exploration is to locate and remove foreign bodies. If glass, gravel or metallic foreign bodies are suspected, radiological expertise with surface markers in place before and after exploration may be useful. However, many organic foreign bodies (e.g. wooden splinters) and many synthetic materials (e.g. plastic) may be missed on a radiograph. Even if no foreign body is suspected, exploration may be necessary for better access for debridement of potentially devitalized tissue and for haemostasis. Wound toilet is the cleansing of the wound with water, saline or antiseptics (e.g. chlorhexidine, cetrimide, povidone iodine). Several litres of warmed isotonic fluid may be needed for large wounds. A soft brush or sponge may be used to gently scrub the wound to clear particulate matter. Wound toilet should be performed at the first available opportunity because bacterial counts increase with time. Debridement is the removal of foreign matter, necrotic and devitalized tissue from the wound. Debridement aims to achieve a clean, raw area that is well perfused and has a low bacterial count. Surgical and mechanical debridement are commonly used in acute wounds, whereas autolytic, enzymatic and biological methods are more relevant in wounds presenting late or in chronic wounds (Table 5). Surgical debridement is the most rapid method and, in posttraumatic wounds, involves excising subcutaneous tissue and muscle until bleeding from the cut edges is satisfactory. Free-lying bone denuded of periosteum must be removed. The skin must not be undermined because the blood supply may be compromised.
of wound edges, heals without complications at the first instance. Advantages of primary closure are good cosmetic effect and shorter time to clinical healing. Primary closure is the preferred method of closure for clean wounds with minimal tissue loss. Primary closure should ideally be performed within 6–8 hours of trauma. However, wounds in vascular areas (e.g. face, scalp) may be closed up to 24 hours after trauma. Secondary closure (healing by secondary or second intention) occurs when a wound which is left open heals largely by formation of granulation tissue and contraction. Wounds that are candidates for secondary closure include those with significant tissue loss precluding tension-free approximation of edges, de vitalized edges, ulcerations, and abscess cavities. There is evidence that the wound contraction that occurs with secondary healing gives a better cosmetic result than early skin grafting in certain situations (e.g. healing of fasciotomy wounds). Tertiary closure (healing by tertiary or third intention) is the delayed closure of a wound after a variable period of time for which it has been left open. In general, tertiary closure is applied to wounds that are grossly contaminated or present late, but do not have significant tissue loss. Wounds that need to be considered for delayed primary closure include those contaminated by soil, manure or faeces, caused by animal bites or projectiles. Such wounds need a thorough wound toilet, exploration and debridement, after which they are observed for 3–7 days before closure. The term ‘secondary suture’ is usually applied when a wound is left open for >10 days, allowing the formation of clean granulation tissue before mechanical closure can be undertaken. Modes of closure: there are two types Direct closure is the closure of wound by approximation of the wound edges. Wound closure includes ensuring a clean wound with satisfactory vascularity and haemostasis, and apposition without tension, inversion or dead space. Tension in the wound may be reduced by the use of subcutaneous sutures or undermining of the wound edges. Eversion
Wound closure Types of healing: the three types of clinical wound healing depend on the timing and method by which wound closure is achieved. Primary closure (healing by primary or first intention) refers to a wound which, when mechanically closed by approximation
Debridement Type
Description
Surgical
Excision of devitalized tissue and particulate matter using sharp instruments. Useful in the following wound types: posttraumatic, infected or necrotic postoperative, chronic. Forced irrigation of saline from a 50 ml syringe through an 18-G catheter applies about 15 pounds per square inch of pressure to remove loose necrotic tissue. An alternative is the wet-to-dry dressing method, in which a moist gauze dressing is allowed to dry on the wound. Removal without wetting results in removal of fibrin and slough. This method as often insufficient, can be painful and may damage underlying epithelium. Topical negative pressure (vacuum-assisted closure) removes exudate and necrotic tissue, and is used in a variety of wounds to reduce the size of the defect (e.g. laparostomies, wounds after pilonidal sinus excision). An occlusive dressing applied to the wound allows wound proteases to liquefy the necrotic tissues, which may be washed away at dressing changes. Collagenase liquefies collagen and elastin (but not fibrin); papain with urea degrades fibrin and collagen. Enzymatic debriding agents should be applied only on non-viable areas of the wound. They are expensive and have a limited role in selected chronic wounds. Medical-grade larvae of Lucilia sericata are necrophagous and are useful in selected chronic wounds.
Mechanical
Autolytic Enzymatic
Biological Table 5
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Basic skills
can be achieved by using vertical or horizontal mattress sutures. Dead space in clean wounds may be obliterated by deep subcutaneous sutures. However, overzealous closure tends to leave a large volume of suture material in the depths and increases the risk of infection. Sutures, staples, skin tapes and cyanoacrylate glue are commonly used in direct closure of wounds. Subcuticular sutures produce a better cosmetic result than percutaneous sutures and are suitable in most postoperative wounds. In post-traumatic wounds, interrupted percutaneous sutures are preferred because they accommodate wound oedema and allow efflux of wound fluid. The smallest-diameter suture necessary to provide wound strength should be chosen. In the face, a 5/0 or 6/0 suture is usually used; 3/0 or 4/0 sutures will suffice in most other areas. Synthetic monofilament sutures are the least reactive and are preferred to silk and catgut. Sutures should be removed in: • 48 hours in the eyelid • 4 days in the face • 7–10 days in the trunk • 10–12 days in the upper limb • 10–14 days in the lower limb. Staples are inert, may be used in most straight lacerations and are particularly useful if quick closure of skin is necessary. They should be avoided in the hands, face and if imaging (CT, MRI) of the area is planned. Skin tapes do not leave scars and are suitable for superficial wounds under no tension and for additional support for the wound after suture removal. Another useful application is in avulsions with doubtful skin viability; for example, a pretibial injury that leaves a distal triangulated flap, where suturing is contraindicated but the flap needs to be replaced back on its bed. Transplanted closure is the term used if non-native tissue (e.g. skin grafts, skin flaps) is employed to achieve closure. Skin grafting can provide wound cover in large raw areas that cannot be closed by direct closure, for example: • wounds following avulsion injuries (especially injuries that cause a distal flap in the leg)
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• raw areas resulting after wound excision for full-thickness burns. Split-skin grafts have a superior take rate, but poorer cosmetic effect when compared to full-thickness grafts. Skin should not be grafted over bare bone, tendon, cartilage, major vessels or an irradiated area. Local or distant flaps are preferred to skin grafting if: • the wound bed is not very vascular • bare tendons or nerves are exposed • the wound is over a bony prominence • radiotherapy or repeat surgery is contemplated • better cosmetic effect is required. Wound drainage: blood and wound fluid collecting within or under a wound may give rise to: • pressure effects (vascular compromise, airway compromise, pressure on nerves, compartment syndromes) • infectious complications (infected seroma, infected haematoma, abscess) • unsightly swellings that may or may not be symptomatic. Wound drainage is usually employed if the risk of a fluid collection is estimated to be high or unacceptable because of anatom ical factors (which lead to pressure effects) or if the volume of collection is anticipated to be high. A closed system of drainage should be employed because it is aseptic. Open systems such as wicks and corrugated drains covered with gauze swabs are not ideal for clean wounds (though they may have advantages in selected contaminated wounds). Drains may fail because of blocked or exposed holes, kinking, or due to thick effluent or coagulum. Suction may make the drains more efficient, but is contraindicated if the drain is close to major vessels or bowel. There are no evidence-based guidelines for the duration of drainage because it depends on the site and complexity of the wound, and the purpose it was employed for. The volume and quality of the effluent should inform decision making. Leaving the drain for too long may act as a foreign body, irritating the raw area and be a potential nidus for infection. ◆
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