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Traumatic Wounds
This article will address the mechanism of injury that causes the wounds and an appraisal of some of the factors to consider in their management. As prevention of infection is one of the main objectives in the care of traumatic wounds, a brief overview of the risks and interventions will be explored. However, it is beyond the scope of this article to address this in any great depth. Lawrence found potentially pathogenic organisms in over 70% of wounds at the time of presentation to Accident and Emergency, indicating infection risk because of contamination (2). However, contamination does not necessarily lead to infection. There is often an extensive time lag between injury and arrival to hospital, particularly if extrication has been difficult and any delay in treatment will result in the multiplication of any organisms present. Whilst most civilian wounds contain less than 105 organisms per gram of tissue in the first 6 hours and are therefore relatively safe to close, wounds associated with multiple injuries mimic wounds of warfare and generally have more organisms per gram of tissue. They will often become infected despite the use of strong antimicrobials (3) and it is highly probable that administering prophylactic antibiotics in high risk patients is ineffective if delayed for more than 6 hours from the time of injury, (4). The decision to use prophylactic antimicrobials is best reserved for those wounds known to be at risk and to deliver them as early as possible. Indiscriminate use in low risk wounds is not warrented, (5). Incisions A sharp neat cut, typically made in a straight, single slash. Classically these are caused by knives but can be due to falling through glass, accidents with sheet metal, in fact anything with a sharp, cutting edge. If these edges can be approximated easily, blood loss can be minimised and the risk of infection is minimal. Deeper wounds involving underlying structures may need more advanced wound repair to eliminate 'dead space' and prevent haematomas forming. Lacerations A tearing type of cut, resulting in a jagged wound edges and potentially devitalised tissue. The amount of devitialised injury can increase the risk of infection developing and will require 'trimming' prior to suturing. Trimming also gives better cosmetic effects. Scalp lacerations can lead to hypovolaemic shock in infants or through delayed closure. Whilst closure of wounds that do not appear to be at risk of causing sudden exsanguination can be safely delayed, the slow steady ooze of as much as half a litre of blood from a deep scalp wound, that perhaps involves the galea is sometimes not fully appreciated. Abrasions A graze - a superficial injury caused by rubbing or scrapping. Despite this it is a very painful injury that may bleed or ooze serous fluid. If someone has been dragged along a dirty pavement or road surface, the wound can be contaminated by ingrained dirt which if not cleaned adequately results in a 'tattooing' effect. Tar can be removed with Polyoxyethylene sorbitan. Polysorbates are found in Sudocream and Flamazine which are available from most pharmacy departments. Soil, that may have become ingrained in the wound, also has a severely damaging effect on tissues. It provides the necessary conditions for the growth of micro-organisms, (6) Contusion A bruise, an injury to the deeper tissues through the skin. Damage to blood vessels results in the classic bluish-purple skin discolouration. The red pigment haemoglobin turns blue as it loses its oxygen and is later broken down into green and yellow bile pigments. Stagnant blood is an ideal environment for bacteria to multiply in. Any slight breach in the surface of the skin can result in infection. Contusions, while classically not breaching the skin's integrity are generally accompanied by other injuries which do. Crush Injuries A force applied to the tissues literally squashes them resulting in a crush injury. The location of the injury determines the mortality or morbidity. For example, crush injuries to the chest, can result in fractures to the sternum and the ribs, and involve internal organs such as the lungs, heart, liver or spleen. If the force is powerful enough it will fracture bones and cause extensive bleeding into the muscle. This can result in something called 'compartment syndrome.' Crush injuries, abrasions and contusions carry a higher risk of infection than simple lacerations because of the amount of devitialised tissue present. Once the blood supply is compressed, healing is impaired as the immune system's effectiveness is reduced. In traumatic wounds there is the added risk of anaerobic organisms e.g. Clostridium tetani and Clostridium welchi, gaining access to the deeper tissues and finding the perfect conditions for their multiplication. However, the indiscriminate use of Povidone iodine dressings as prophylactic agent has been questioned, (7). Penetrating wound Penetrating wounds such as stabbing injuries carry micro-organisms and clothing debris deep into the wound. Cat bites are also penetrating wounds because of the animal's long front incisors. It has to be considered when assessing these wounds, particularly those of the hands, the joint spaces may have been penetrated. Puncture wounds contaminated by soil or animal faeces carry a high risk of infection by gram negative organisms such as Clostridium tetani or Clostridium Welchii. Bites Pastuerella multicoda is a common organism found in animal bites. Human bites are another issue all together. Maimaris and Quinton have demonstrated that adequate debridement and thorough wound toilet permit early closure of dog bites (8). The degree of risk with bites really depends on the type of animal! Small dogs which grip and shake their prey generate extensive, crushing injuries. Those which rip and tear create a mixture of crushing, penetrating and laceration. Others such as cats pounce and hold which creates deep penetrating wounds. Humans create a mixture of crushing, tearing and incising injuries worsened by a mixed mouth flora. Degloving injury An injury that results from shearing forces literally ripping the skin from the underlying tissues. Blood vessels connecting the dermis to underlying muscle or periosteum are ruptured and the skin dies. Sometimes the skin appears to be still attached but moves around the limb like a glove, hence the name of the injury. Extensive skin grafting is required and the end results are generally of poor cosmetic appearance.
trauma.org 5:10 - October 2000 References
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