Advanced Wound Management: Nine Myths and Realities (2008)

Transcription

1 Advanced Wound Management: Nine Myths and Realities (2008) Marvin A. Wayne, MD, FACEP; Adam J. Singer, MD, FACEP Wherever wounds occur on the body, the goals of wound management are the same: early closure, prevention of infection, a cosmetically appealing scar, and a functional scar. All of the steps taken in managing wounds aim for these results. The history of wound closure is an interesting and somewhat bizarre one. The first written records of the treatment of wounds date from around 2,500 BC. Plants figured prominently in their treatment for more than 1,000 years. Herbs were applied in a balsam, leaves and grasses were used as bandages. Honey, butter, clay, and bark were used as medicines; urine, dung, and blood were used more for ritualistic significance. During the Middle Ages purulence was considered essential for wound healing. As a result, wounds were intentionally contaminated to produce pus. The earliest record of using sutures to close wounds comes from a mummy dating from 1100 BC. An early form of staples (developed in the early 20th century) can also be found in the ancient Hindu civilization where wounds were closed with the jaws of dead ants. The number and varieties of wounds seen by emergency physicians justify continuing interest in their care. In 2005, the most recent figures provided by the National Center for Health Statistics, of approximately 120 million emergency department visits, there were 12 million wounds, 7 million lacerations, 2.5 million abscesses, and 430, 000 burns serious enough to be treated in the ED. Lacerations occur in many parts of the body, which often influences how they are treated. Lacerations most commonly occur on the upper extremities (38%), face (27%), and trunk (13%) with eleven percent each on the lower extremities and in the head and neck area. With a long history of technique and reported results, many myths about the management of wounds still abound. This article examines some of the most common ones. Myth #1: Keeping wounds dry prevents wound infection and speeds healing Until the mid 20th century wounds were kept dry to avoid infection. Studies in pigs showed that the occlusion of partial thickness wounds doubled the rate of re-epithelization. Early studies in humans seemed to confirm that occluded wounds healed faster. Later studies have confirmed the advantages of moist wound healing. It has been shown that a moist wound healing environment helps prevent cell dehydration and death. It also promotes angiogenesis, improves phagocytosis, and growth factor elaboration. Further it improves the rate of reepithelialization, reduces pain and improves the cosmetic outcome. Those who objected to the moist healing strategy based their opinion on the concern that under occluded dressings, bacteria proliferated and would cause infection. However, most studies have not confirmed this suspicion. In fact, a meta-analysis, of over 3000 wounds covered with occlusive dressings or gauze, demonstrated that wound infection rates were significantly lower with occlusive dressings: 2.6% of those with occlusive dressings became infected versus 7.1% of those with gauze dressing, with a significant P value. Reality: Infection rates are lower and healing is faster when wounds are kept moist. 1

2 Myth #2: Using sterile technique for lacerations commonly seen in the emergency department is necessary to prevent wound infection It may seem counterintuitive that there should be a question of whether or not sterile technique will prevent wound infection. However, a study of the effect of using caps and masks on infection rates is revealing. A study of 442 lacerations, of which 239 were repaired using a cap and mask, and 203 without them, demonstrated that the incidence of infection was 2.5% in wounds treated with clinicians wearing caps and masks, and 3.9% in those treated without the presence of caps and masks with no statistically significant difference between the groups. Thus, caps and masks do not seem to prevent infection. As always, common sense should prevail. A mask should be used when the practitioner has a respiratory infection and is sneezing and coughing. Another study looked at sterile vs. non-sterile gloves as a factor in wound infections. A multicenter, single blind, randomized study looked at 816 patients randomized to laceration repair using sterile and non-sterile gloves. Most of the wounds were sutured; 25% were treated with topical antibiotics. Ninety-seven percent were followed up within one week. Of those in the sterile glove group, 6.1% developed infection vs. 4.4% in the non-sterile group. Several other similar studies have also come to the same conclusion. Reality: Using caps, masks, and sterile gloves do not appear to be necessary for the average laceration treated in the emergency department. Myth #3: Irrigation of facial and scalp lacerations is necessary to prevent wound infection While there is evidence that irrigation lowers infection rates in contaminated wounds created in animals, there is no evidence that irrigation is effective in clean, low-risk wounds in humans. Overall infection rates after traumatic laceration repair in the ED are around 3-5%, and even lower in well vascularized facial and scalp lacerations. To examine whether high pressure irrigation is necessary in facial and scalp wounds, an observational study of 1,923 wounds, of which 1,090 were irrigated and 833 were not, compared both infection rates and cosmetic outcome of low-risk wounds based on whether or not they were irrigated. (The cosmetic parameter was added because high pressure irrigation might cause wound distortion that is difficult to correct.) The groups compared were similar in terms of patient demographics and wound characteristics: length of wounds, layers of closure, and use of antibiotics. The results of this study were that infection rates were similar in those whose wounds were irrigated (0.9%) and those whose wounds were not (1.4%). In terms of cosmetic outcome, 76% of the irrigated group achieved a good result, while 82% of the non-irrigated group achieved a good result. While the difference between groups in cosmetic outcome was not statistically significant there certainly was a trend (P=0.07) favoring no irrigation. Reality: Irrigation of low-risk facial and scalp lacerations of the type generally seen in the emergency department does not lower the incidence of infection, but may result in a less optimal cosmetic result. Dirty or highly contaminated wounds still 2

3 require meticulous cleansing and irrigation. Myth # 4: Saline is more effective than tap water in preventing wound infection Somehow the idea of running tap water over a wound seems less appropriate than irrigating it with saline solution. However, saline costs more than tap water and is not readily available outside of the hospital. Is there any evidence that saline is more effective than tap water at preventing wound infections? A randomized, controlled study of 530 wounds in pediatric patients treated in the emergency department was designed to compare wound infection rates. Saline was used is 271 patients, tap water was used in 259. While the baseline characteristics in both study groups were fairly similar, there were more hand lacerations in the group randomized to tap water irrigation (which would tend to increase the rate of infections in this group!) The results were as follows: of the saline-irrigated group, 2.8% developed an infection. Of the tap-water irrigated group, 2.9% developed an infection. There was no difference whatsoever between the tap water and saline. Other studies have mimicked these results. Thus there is no evidence that saline is more effective than tap water in preventing infection, yet it is commonly used in the United States at considerable expense to healthcare institutions. In other countries in the world where saline is unaffordable, tap water is used. Assuming the tap water is not contaminated, it seems to be effective. Reality: Saline is no more effective in preventing wound infections than tap water. Myth #5: There is a direct relationship between the time interval from injury to closure and wound infection rates One of the oldest wound controversies concerns the length of the so-called golden period of the wound. This period refers to the time interval between wound injury and closure when it is still safe to close wounds without significantly increasing the risk of infection. Some have recommended that wounds older than 6-12 hours not be closed. Several studies have come up with different results based on the types of wounds and patients. One of the largest studies comes from Jamaica where many of the patients have dirty wounds and present relatively late to the ED. This study was an observational study that compared healing rates at 7 days, without infection, between wounds closed within and beyond 19 hours of injury. The results of this study are representative of other studies demonstrating that lacerations over the face, head and neck can be safely closed even after 19 hours without increasing the risk of infection. In contrast, lacerations over the lower extremities and trunk have an increased risk of infection and non-healing when closed after 19 hours from injury. Thus the golden period of the wound needs to be individualized based on patient and wound characteristics including, but not limited to, wound location. Reality: For wounds on the face, head, and neck, there is no evidence that delayed closure results in any increase in the rate of wound infection. Wounds on the truck, arms, and legs probably should not be closed after 6-12 hours. Myth #6: Mammalian bites treated with primary closure have an increased wound 3

4 infection rate. An observational study from 2000 looked at 145 patients with mammalian bites from dogs, cats, and humans (not many human bites were included) treated with primary closure, with a mean time from injury to treatment of up to 1.8 hours. Fifty seven percent were on the head and neck, and 36% were on the extremities. The infection rate in these patients with bite wounds was 5.5%, compared with infection rates for non-bite wounds of 3-7%. Essentially, the infection rate was the same. What about dog bites specifically? In 1988, 96 patients with 169 wounds were studied in a randomized clinical trial. Of these, 92 wounds were randomized to suturing and 77 were left open. Most of the wounds were short and on the hands. The average delay from wound to treatment was 2.5 hours. No systemic antibiotics were given in any of the patients. The rate of infection in both groups of patients was approximately 8%. Since the cosmetic outcome of facial lacerations is so important and overall infection rates in this area tend to be low, most facial lacerations are sutured, regardless of whether they are caused by dog, cat, or human bites. When it comes to extremities, where infection rates are higher and cosmesis less important, most small puncture wounds are closed while large wounds are loosely closed and patients are given oral antibiotics for prophylaxis. What about giving antibiotics to prevent infection in patients with dog bites? In eight randomized studies reported in the 2001 Cochrane database it was clear that antibiotics reduced infections in wounds caused by human bites, but did not reduce infections caused by dog or cat bites. However, regardless of the cause of extremity bites, these wounds benefited most from prophylactic systemic antibiotics. Reality: Lacerations on the face from any mammalian bite (especially if large) can be sutured. Regarding antibiotics, studies confirm that antibiotics reduce infections in wounds caused by human bites, and for extremity bites. Myth #7: Sutures are the best wound closure device for lacerations. While sutures have been around the longest, the question is what is the best or most appropriate method of closing wounds: sutures, staples, surgical tapes, or topical skin adhesives? All of the currently available wound closure devices have a role in wound closure, each with a set of advantages and disadvantages. Sutures are the time-honored method of closing wounds, but they are painful to insert and painful to remove for the patient. They are relatively expensive, there is a risk of a needle stick injury for the provider, they are time consuming to put in, operator dependent, and they cause greater tissue reactivity than the other wound closure devices. On the other hand, sutures provide the most meticulous closure, the greatest tensile strength, and the lowest dehiscence rate. Another major disadvantage of sutures is that most require removal. Sutures that are left in the skin beyond 7 days tend to result in the formation of ugly dots on either side of the wound. Fast absorbing sutures may be used to avoid the need for removal. In general, sutures are the most appropriate wound closure device for complex and high tension wounds and over areas where other devices may be inappropriate, such as the hair and mucous membranes. 4

5 Staples are excellent for scalp wounds. Other than washing them out, no further dressings are required. Staples are quick to apply, require little training, have low tissue reactivity, are low cost, and there is a very low risk of a needle stick. The disadvantages are that they result in a less meticulous closure, they may interfere with imaging, and they require removal, which can be painful. Surgical tape is inexpensive, has the lowest infection rates in animal models, is rapid to place, comfortable for the patient, and is the least tissue reactive of all the wound closure devices. However, the tape tends to fall off, cannot get wet, cannot be used over hair, has low tensile strength, and can cause blister formation. Surgical tapes can be used to reinforce wounds after removal of sutures or staples when the wound s bursting strength is quite low. The cyanoacrylate topical skin adhesives were first synthesized in 1949 and first used clinically in Their application is rapid, simple, painless for the patient, and relatively inexpensive. The material is a liquid monomer that polymerizes into a solid polymer upon contact with tissue anions. It is applied topically and bonds the apposed wound edges. Since the topical adhesive sloughs off spontaneously in 5-10 days as the skin renews itself, device removal is unnecessary. However, the topical adhesives are not very useful for hands and feet and for wounds directly over bending areas. Fingernail bed injuries can be closed with a topical adhesive as well as hand lacerations that are to be splinted over the next 5-10 days. The topical skin adhesives are extremely valuable for fragile skin (such as skin tears and shin lacerations). They are not particularly useful in an around mucous membranes since they tend to fall off prematurely. Extreme care should be used in lacerations around the eyes in order to prevent inadvertent runoff and matting of the eyelids. If it does get into the eye, use ophthalmic ointment to hasten sloughing of the adhesive. Reality: Sutures are not the only effective means of wound closure. Effective alternatives exist depending on wound type and location. Myth #8: Double layer suturing yields better cosmesis for facial wounds than single layer suturing Emergency physicians rarely use deep sutures. In contrast, plastic surgeons frequently use deep sutures in the face. Is there any proof that deep sutures lead to a better result in terms of infection and scar formation? Scar width is related to wound tension and correlated with the force required to close the wound. On the other hand, deep sutures increase infection rates in contaminated animal wound models. What is the evidence that deep sutures are beneficial in closing facial lacerations? A small study looking at 17 patients who were undergoing laminectomy, in whom there was closure of the upper and lower parts of the incision randomly with or without 4/0 subcuticular polyglycolic acid in addition to percutaneous nylon sutures, concluded that the width of the scar was unaffected by the presence of subcuticular sutures. A larger trial looked at time to closure and cosmesis in 60 patients with non-gaping (<10 mm width) facial lacerations randomized to a single layer of uninterrupted 6/0 polypropylene sutures or a double layer of deep dermal buried 5/0 polyglactin sutures plus simple interrupted 5/0 polypropylene sutures. The authors concluded that there was no benefit in using deep sutures in addition to the superficial single layer of percutaneous interrupted sutures. In fact, there was a time advantage in using only a single layer of sutures (six minutes) that would be expected. 5

6 Reality: In non-gaping facial lacerations there is no benefit in using double layer vs. single layer suturing. Deep dermal sutures may still be required in high tension gaping facial lacerations. Myth #9: The use of epinephrine for digital block may result in digital gangrene. Since 1888, there have been 48 cases of digital gangrene after the administration of anesthetic. In 21 of these cases epinephrine was used, however, its concentration was unknown and in many of these cases tourniquets were used making interpretation of this data difficult. In contrast there have been no reports of digital gangrene since 1948 when a commercial combination of epinephrine in lidocaine was introduced. A 1991 study randomized patients undergoing hand surgery to digital blocks with lidocaine with or without epinephrine and found no cases of gangrene. Furthermore, the addition of epinephrine reduced the need for additional injections of anesthetic and use of tourniquets, which are far more detrimental to digital blood flow than epinephrine. An ultrasonic study of digital blood flow found that injection of epinephrine resulted in a transient decrease in blood flow that completely resolved within minutes. A recent observational report of over 5000 patients undergoing digital block with lidocaine and epinephrine failed to demonstrate any cases of digital gangrene or any other complications. Reality: There is no evidence that the use of epinephrine is associated with digital gangrene. While it may have a vasoconstrictive effect, that effect may actually be desirable, and resolves within minutes. These are just some of the many myths that have purveyed our specialty concerning wound care. We all need to keep an open mind and look at the evidence behind so much that we have held to be realities. As always, clinical judgment and common sense should also be taken into consideration when determining how best to manage individual wounds. 6

7 ADDITIONAL READING 1. Singer AJ, Thode HC, Hollander JE. National trends in ED lacerations between Am J Emerg Med 2006;24: Hinman CD, Maibach H. Effect of air exposure and occlusion on experimental human skin wounds. Nature 1963;200: Hutchinson JJ. Prevalence of wound infection under occlusive dressings: a collective survey of reported research. Wound 1989;1: Perelman VS, Francis GJ, Rutledge T, Foote J, Martino F, Dranitsaris G. Sterile versus nonsterile gloves for repair of uncomplicated lacerations in the emergency department: a randomized controlled trial. Ann Emerg Med. 2004;43: Hollander JE, Richman PB, Werblud M, et al. Irrigation in facial and scalp lacerations: does it alter outcome? Ann Emerg Med 1998;31: Hollander JE, Singer AJ. Laceration management. Ann Emerg 1999;34: Singer AJ, Hollander JE, Quinn JV. Evaluation and management of traumatic lacerations. New Engl J Med 1997;337: Moscati RM, Mayrose J, Reardon RF, Janicke DM, Jehle DV. A multicenter comparison of tap water versus sterile saline for wound irrigation. Acad Emerg Med. 2007;14: Berk WA, Osbourne DD, Taylor DD. Evaluation of the golden period for wound repair: 204 cases from a third world emergency department. Ann Emerg Med 1988;17: Chen E, Hornig S, Shepherd SM, Hollander JE. Primary closure of mammalian bites. Acad Emerg Med 2000;7: Medeiros I, Saconato H. Antibiotic prophylaxis for mammalian bites. Cochrane Database of Systematic Reviews 2001, Issue 2. Art. No.: CD Singer AJ, Quinn JV, Hollander JE, Clark RE. Closure of lacerations and incisions with Octylcyanoacrylate: A multi-center randomized clinical trial. Surgery 2002;131: Singer AJ, Gulla J, Hein M, Marchini C, Chale S, Arora B. Single vs double layer closure of facial lacerations: A randomized control trial. Plast & Reconstr Surg 2005;116: Krunic AL, Wang LC, Soltani K, Weitzul S, Taylor RS. Digital anesthesia with epinephrine: an old myth revisited. J Am Acad Dermatol. 2004;51:

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