Wounds must be anesthetized with either local or regional techniques prior to cleansing and repair. Local anesthesia distorts wound edges; therefore regional nerve blocks should be used where appropriate (e.g., the hand, face, ear, nasal cartilage, palm, sole). Refer to Chapters 123 through 129 for a complete discussion of local anesthetic agents, regional anesthesia, topical anesthesia, nitrous oxide anesthesia, and procedural sedation.
Lidocaine (Xylocaine) in a dose not to exceed 4.5 mg/kg is an effective and standard local anesthetic agent. Lidocaine anesthesia lasts approximately 60 to 90 minutes. If a longer period of anesthesia is required, bupivacaine may be used. It provides approximately 120 to 180 minutes of anesthesia. The addition of a 1:100,000 dilution of epinephrine to lidocaine or bupivacaine will prolong the duration of anesthesia, promote hemostasis, allow a larger dose to be used, and reduce systemic absorption of locally infiltrated local anesthetic solution. Epinephrine is a potent vasoconstrictor and should not be used near end organs such as the fingers or toes. It may decrease blood flow and induce ischemia. Epinephrine should also be avoided near the tip of the nose, the ear, and the penis.
Animal model studies have consistently shown that epinephrine increases the incidence of infection in contaminated wounds. This may be due to vasospasm-induced local ischemia. Epinephrine should not be used to enhance local anesthesia in contaminated wounds. Consider the use of regional anesthesia or procedural sedation in these patients.
The pain of local anesthetic injection can be reduced. The use of a 27 or 30 gauge needle, slower and deeper infiltration (into the dermis), warming the local anesthetic solution, and the addition of bicarbonate to lidocaine (9 mL lidocaine to 1 mL of bicarbonate) may decrease the pain of anesthetic injection.21–26 Other strategies involve anesthetizing as much tissue as possible through a single site, starting proximally on the extremity and moving distally. Infiltration of the local anesthetic solution through the wound edges is less painful than through intact skin.
Most “allergic” reactions are actually vasovagal or other adverse responses. Allergies to “caines” are attributed to what is often a vasovagal or other side effect. True allergies to local anesthetics are rare and are generally seen only with the ester class of local anesthetics. If an allergy to lidocaine (an amide class of local anesthetic) is suspected, the use of an ester class of local anesthetic is suggested. An alternative is the use of cardiac lidocaine, the prefilled syringes used in codes and cardiac arrests, which contains no preservative. It is felt that the preservative in lidocaine is responsible for the allergic effect. Another alternative is to use a 1% to 2% solution of diphenhydramine (Benadryl). This provides adequate but not ideal anesthesia. The most common complication of local anesthesia infiltration is hypotension and bradycardia as a result of a vasovagal reaction.
Topical anesthesia is an attractive alternative to injection, particularly in the management of pediatric patients with simple wounds. Lidocaine, epinephrine, and tetracaine (LET) gel or tetracaine, adrenaline, and cocaine (TAC) are two agents that can be used as effective local anesthesia.27 Both of these agents contain epinephrine and should not be used on areas involving an end artery or contaminated wounds. TAC involves expense and incorporates problems with the use and maintenance of a controlled substance. TAC also has the potential for toxicity, especially when applied to mucosal surfaces. EMLA (eutectic mixture of local anesthetics) cream, also used for local anesthesia, has been found to provide effective anesthesia for extremity lacerations. EMLA is a combination of 2.5% lidocaine and 2.5% prilocaine suspended in an oil-in-water emulsion. Studies have found that it takes longer to obtain optimal anesthesia with EMLA than with TAC.28
Meticulous preparation of the skin surrounding the wound and the actual wound, irrigation, and wound debridement are tantamount to good wound healing. The goal is to remove bacteria, foreign matter, and tissue debris. Wounds should be adequately anesthetized prior to cleansing and/or local exploration. Adequate light, anesthesia, and equipment are a must in order to avoid inadequate debridement, a retained foreign body, or a wound hematoma that can result in a necrotizing soft tissue infection.
Disinfecting the intact skin surrounding the wound and ridding it of foreign bodies, debris, and particulate matter is the initial step in wound preparation. This technique can be accomplished by scrubbing the skin with povidone iodine, chlorhexidine, or poloxamer 188 (Shur Clens) skin-prep solutions. Do not expose the wound itself to these solutions. Povidone iodine and chlorhexidine solution are bactericidal and work as it dries. Its toxicity to wound tissue is controversial. Shur Clens has no tissue toxicity but also has no antibacterial activity. A wide area surrounding the wound should be prepped with an antimicrobial agent, preferably povidone iodine or chlorhexidine solution.
Hair removal is often unnecessary prior to closing wounds, can be embarrassing for the patient after discharge from the Emergency Department, and may increase the risk of wound infection. Shaving can cause minimal soft tissue trauma and wound infections.17 Eyebrows should never be shaved, as they can grow back unpredictably or not at all. Simple scalp lacerations can be exposed by using antibiotic ointment (or lubricating gel) to move the hair away from the wound margins prior to placing sutures.
Wound cleansing and preparation have been proven to be the foundations of proper wound management and the prevention of wound infections. Irrigation removes contaminants, reduces infection, and improves visualization. There are two concerns regarding wound irrigation: the pressure required for adequate cleansing of the wound and the means to irrigate the wound safely while protecting the healthcare worker from the threat of human immunodeficiency virus and hepatitis B (by contamination of their own skin surfaces, mucosal surfaces [eyes, nose, or mouth], or minor open skin wounds).
Irrigation pressures of 5 to 8 pounds per square inch (psi) are felt to be adequate to cleanse a wound that is not heavily contaminated. This surface pressure can be generated by the combination of a 35 mL syringe and a 19 gauge angiocatheter held 2 cm from the wound surface.18,40–42 Unfortunately, this process can be quite messy (Figure 92-1). High-pressure irrigation, which generates peak pressures of 25 to 40 psi, has been a controversial issue in the Emergency Medicine literature. The theory is that high pressures may cause tissue disruption and increase infection rates. High-pressure irrigation should be reserved for highly contaminated wounds. High-pressure irrigation may drive contaminants deeper into puncture wounds and should be avoided.
Wound irrigation with an angiocatheter on a syringe. This process is quite messy and can result in an occupational exposure. (Photo courtesy of Zerowet Incorporated.)
Though there are a variety of irrigation fluids, the optimal type is unknown. Normal saline is the most commonly used irrigant. The volume of irrigation fluid to be used has not been well established. The use of 100 to 300 mL has been suggested in the literature. Heavily contaminated wounds require larger amounts of irrigant. Anecdotal recommendations suggest using 50 mL/cm for clean wounds and 100 mL/cm for dirty wounds. Heavily contaminated wounds may have to be scrubbed (after adequate anesthesia) with fine-mesh gauze or a micropore sponge using a 1% solution of povidone iodine or poloxamer 188. Tap water can be used for irrigation with no increased incidence of infection, especially when a large volume of irrigant is required.43–47 Soaking of wounds is discouraged as a poor substitute for the preparation of contaminated or clean wounds. Do not soak wounds in any fluid. Soaking does not reduce bacterial contamination or decrease infection rates. It may actually increase infection rates. Do not use undiluted povidone-iodine, hydrogen peroxide, or detergents in the wound as they cause tissue toxicity.48
Numerous commercially available devices are available to irrigate a wound (Figure 92-2). The Combiport (Moog Medical Devices, Salt Lake City, UT) is a wound irrigation device that inserts directly into the port of an intravenous fluid bag (Figure 92-2A). Squeeze the bag of saline and direct the stream of fluid through the device and into the wound. Wound Wash Saline (Church & Dwight, East Princeton, NJ) is sterile normal saline within a pressurized can (Figure 92-2B). Direct the tip of the can toward the wound, press the button, and direct the saline stream into the wound. This is also available at retail stores for patients to use at home for wound care. The company offers a convenient chart that uses wound depth and base characteristics to determine how much saline to use to irrigate the wound. The can controls the pressure (6 to 13 psi), so that tissue is not devitalized during the irrigation. Unfortunately, using this method is quite messy as the saline and wound materials (e.g., tissue fluid, blood, and debris) splash all over.
Commercially available wound irrigation devices. A. The Combiport Wound Irrigation Device (Moog Medical Devices, Salt Lake City, UT). B. Wound Wash Saline (Church & Dwight, East Princeton, NJ). C. The Zerowet Supershield (Zerowet Inc., Palos Verdes Peninsula, CA). D. The Combiguard (Moog Medical Devices, Salt Lake City, UT) attaches to the Combiport or a syringe. E. The Igloo Wound Irrigation System (Photo courtesy of Bionix Medical Technologies, Toledo, OH). F. The Irrijet (Cooper Surgical, Trumbull, CT). G. The Canyons Wound Irrigation System (Wolf Tory Medical Inc., Salt Lake City, UT). H. The Squirt Wound Irrigation Kit (Merit Medical Systems Inc., South Jordan, UT). I. The Klenzalac (Zerowet Inc., Palos Verdes Peninsula, CA). J. The Splashcap (Splash Medical Devices, Atlanta, GA). K. The Irrisept (Photo courtesy of Irrisept, Gainesville, FL).
The Emergency Physician should use barrier protection to shield their face, eyes, skin, and submucosal surfaces during the irrigation process. There are several barrier devices on the market that decrease the splatter of irrigation fluid19 (Figure 92-2). Some of these devices are preattached to a wound irrigation device. Others can be attached to a wound irrigation device. The Zerowet Supershield (Zerowet Inc., Palos Verdes Peninsula, CA) is a dome-shaped device that attaches to a syringe (Figure 92-2C). The Combiguard Irrigation Splash Guard (Moog Medical Devices, Salt Lake City, UT) is similar in function to the Zerowet Splashield and has a slightly different shape. The Combiguard can attach to a syringe or the Combiport Wound Irrigation Device (Figure 92-2D). The Igloo Wound Irrigation System (Bionix Medical Technologies, Toledo, OH) is a similar device that provides a multiport shower effect to deliver the irrigation solution (Figure 92-2E). The Irrijet (Cooper Surgical, Trumbull, CT) is a spring-loaded, self-refilling system that is operated with one hand (Figure 92-2F). A Splashield or Splash Guard can be attached to the Irrijet. The Canyons Wound Irrigation System (Wolfe Tory Medical Inc., Salt Lake City, UT) is a similar device with the exception of using the built-in Zerowet Splashield (Figure 92-2G). The Squirt Wound Irrigation Kit (Merit Medical Systems Inc., South Jordan, UT) is a manually operated system that may be used alone or attached to the Splashield, Combiguard, or an angiocatheter (Figure 92-2H). The Klenzalac (Zerowet Inc., Palos Verdes Peninsula, CA) is a similar device with the exception of using the built-in Zerowet Splashield (Figure 92-2I). The Splashcap (Splash Medical Devices, Atlanta, GA) attaches to a bottle of sterile saline (Figure 92-2J). The Irrisept (Irrisept, Gainesville, FL) attaches to a proprietary bottle containing a saline and chlorhexidine mixture (Figure 92-2K).
Debridement creates straight and clean wound edges that are easier to repair by removing tissue that is devitalized, contaminated by bacteria, or contaminated by foreign matter and may impair the ability of the tissue to resist infection. Successful wound closure may require the transformation of a ragged laceration, the removal of devitalized tissue, or the removal of contaminated tissue in order to convert a traumatic wound into a surgical wound. Devitalized and necrotic tissue must be removed in order to remove a nidus for bacterial growth and wound infection.20
Close approximation of the wound requires that debridement of jagged edges not be too vigorous in order to avoid widening the scar and making it difficult to close. Wounds of the face or areas that are devoid of redundant tissue require conservative debridement. Debridement to simplify wound closure is not always the answer for a superior cosmetic result in the repair of irregular wound edges. The meticulous repair of complex wound edges can often provide a superior cosmetic result.
Debridement can be accomplished mechanically, hydrodynamically, or with a combination of both methods. Tissue must be removed mechanically with a #11 or #15 scalpel blade or a scissors (Figure 92-3). Superficial debris and contaminants can be removed with a pulsatile stream of normal saline solution during the irrigation process. Debridement must be performed using aseptic technique. Scrubbing is not a substitute for debridement of heavily contaminated tissue. Wound edges should be handled delicately or gingerly in order to avoid further soft tissue damage and devitalization of injured tissue.
Wound debridement. Removal of the wound edges with a scissors (or a scalpel).
The entire wound may be excised in areas of excess tissue or tissue laxity if no blood vessels, nerves, tendons, or joints lie within or at the base of the wound (Figure 92-4). The excision of a wound creates smooth, clean edges that may be approximated with sutures. This is especially useful in wounds that are heavily contaminated. Most wounds are excised with an elliptical incision (Figure 92-4). Other types of wound excision are discussed in Chapters 95 and 96.
Wound excision. Removal of an ellipse of tissue that contains the wound results in smooth, clean edges that can be approximated.
Carefully plan the excision before removing any tissue. Mark the edges of the proposed incision with a marking pen. The long axis of the ellipse should be two-and-a-half to four times as long as the greatest width of the ellipse. Removal of too much tissue will produce a large defect that may not be possible to close primarily. Remove the tissue using aseptic technique, preventing any contamination of the new wound edges.
The undermining of tissue creates a “flap” that involves the separation of the skin and superficial subcutaneous tissue from the deeper subcutaneous tissue and fascia (Figure 92-5). The process of undermining tissue minimizes skin tension, allows for eversion of the approximated skin edges, and relieves the extrinsic tension from sutures. Undermining is performed when the wound cannot be closed due to a tissue defect or if a wound is under tension. This procedure requires the Emergency Physician to be familiar with the local anatomy so that no blood vessels, nerves, or tendons are injured in the process. Do not undermine contaminated wounds. Undermining large areas can separate the skin from its underlying blood supply and result in a diminished blood flow that predisposes the area to infection and necrosis. Undermining may be useful on the forehead, scalp, arm, forearm, thigh, calf, and torso. Never undermine wounds on the palms, soles, and face.
Wound undermining. A. Sharp undermining with a #15 scalpel blade. B. Blunt undermining with a Mayo scissors.
Undermine tissue at the dermal-epidermal junction or within the subcutaneous adipose tissue. The amount of undermining necessary to close a laceration is approximately double the width of the gap of the laceration at its widest point. A 1 cm wide laceration should be undermined for 1 cm on both sides of the wound, including the ends (Figure 92-5). The use of a Mayo scissors versus a #15 scalpel blade to undermine tissue is based on physician experience and preference. A Mayo scissors is recommended as it may cause less secondary injury, especially in experienced hands.