Burn Injuries PDF

Burn   More then 60% of burn injuries are admitted to hospitals with specialized burn centers.  A significant portion of morbidity & mortality associated with burn injuries is due to associated injuries (e.g., inhalation injury). Intr...

Burn   More then 60% of burn injuries are admitted to hospitals with specialized burn centers.  A significant portion of morbidity & mortality associated with burn injuries is due to associated injuries (e.g., inhalation injury). Introduction  More than 90% of all burns are considered preventable (education, legislative efforts).   Decreases of burn incidence and hospitalization are  attributed to  ❖fire and burn prevention education, Introduction  ❖regulation of consumer products,  ❖implementation of occupational safety standards.   Recent decline in mortality is attributed to  ❖early excision and closure of the burn wound  ❖management of burn patients in specialty burn units, Introduction  ❖improved resuscitation,  ❖control of infection, &  ❖support of the hypermetabolic response.   Not all burns are caused by fire.  Tissue damage may be secondary to chemicals, hot liquids, tar, electricity, Etiology lightning, or frostbite.   Represent the majority of all burns. Thermal  They may result from flame, flash, steam, or scalding liquid. Burns Thermal Burns   Scalds from hot liquids are the most common cause of all burns.  Exposure to water at 60° C for 3 seconds can cause a deep partial-thickness or full-thickness burn. Thermal  If water is 69° C, the same type of burn occurs in only 1 second. ( fresh brewed coffee is about 82° C). e.g., Burns (Scald  Common liquids that cause scalds  ❖Tap water scalds (most common) Burns)  ❖Soups and sauces  ❖cooking oil and grease (When used for cooking, may reach 204° C).  Adults older than 60 years disproportionately suffer burns from hot liquids Thermal Burns (Flame  The number of house fires has decreased with increased use of Burns smoke detectors. Most flame burns are caused by careless smoking, motor vehicle crashes, and clothing ignited from stoves or space ) heaters.   As electricity passes through the body and meets resistance from body tissues, it is converted to heat in direct proportion to amperage and the body’s electrical resistance.  It initially passes through the skin, causing an external burn at the entry and exit sites (extensive damage internally between these sites ). Electrical  Nerves, blood vessels, and muscle are less resistant and more easily Burns damaged than bone or fat.    The smaller the body part through which the electricity passes, the more intense the heat and the less it is dissipated.  Consequently, extensive damage can occur in the fingers, hands, Electrical forearms, toes, feet, and lower legs. Burns  Papillary muscle damage may lead to sudden valvular incompetence and cardiac failure.   Chemicals cause a denaturing of protein within the tissues or a dryness of cells.  Chemical concentration and duration of exposure determine extent of the burn.  Alkali products usually cause more tissue damage than acids. Chemical  A wet chemical should be removed as soon as possible by flushing Burns with copious amounts of water.  Dry substances should be brushed off the skin  before the area is flushed.   Chemical burns can be deceiving as to depth ; appearances can be similar in surface discoloration until tissue begins to slough days  later. Chemical  Consequently, all chemical burns should be considered deep partial thickness or full thickness until proven otherwise. Burns  After chemical removal, wounds are managed in the same manner as thermal burns.   Actual freezing of tissue from exposure to freezing or below- freezing temperatures.  Body response to cold environment is vasoconstriction of peripheral blood vessels to reduce heat exchange Frostbite  When extremities are left unprotected, intracellular and extracellular fluids can freeze, forming crystals that damage local tissues.   Blood clots may form and impair circulation to the area.  The affected extremity should be rapidly rewarmed using warm water.  Use of excessive heat such as steam is dangerous and can cause unnecessary damage. Frostbite  Dress the rewarmed extremity and immobilize it with a padded splint.  Frostbite can be very painful, so pain management is needed   Burn depth and extent are assessed to determine the severity of burn injury. Burn  In many cases final determination is not made for several days. Assessment   Burns are described as partial thickness (2 degree) or full thickness (3 degree).  A more accurate determination of depth can be made between 48 and 72 hours.  Depth determination is not a priority during initial resuscitation. Depth of Burn   Extent of injury for thermal and chemical injuries is assessed by Extent of Burn using formulas such as the rule of nines.   To correct for age 1% is subtracted from the head for each year of age through 10 years, and 0.5% is added to each lower extremity.  To estimate scatter burns, the size of the patient’s palm (including fingers) is used to represent 1% of total BSA (TBSA). Extent of Burn  When discussing an electrical injury, describing the injury anatomically is more important than calculating percentage of BSA burned.   Based on assessment of extent and depth of injury, patient age, presence of concomitant injuries, smoke inhalation, and preexisting diseases. Severity of Burn   Criteria for Transfer to a Burn Center:❖Partial-thickness and full- thickness burns greater than  10% total body surface area (TBSA) in patients less than 10 years or over 50 years of age.  Partial-thickness and full-thickness burns greater than 20% TBSA in other Severity of age groups.  Burns that involve the face, eyes, ears, hands, feet, genitalia, perineum, or Burn major joints.  Full- thickness burns greater than 5% TBSA in any age- group.  Electrical burns, including lightning injury.  Significant chemical burns.  Inhalation injury.  Burn injury in patients with preexisting medical disorders that could complicate management, prolong recovery, or affect mortality.  Any patient with a burn injury that has concomitant trauma poses an increased risk of morbidity or mortality, and may be treated initially in a trauma center until stable before being transferred to a burn center.  ❖Children with burn injuries in hospitals without qualified  personnel or equipment for the care of children.  ❖Burn injury in patients who will require special social,  emotional, or long-term rehabilitative intervention, including  cases involving suspected child abuse and neglect.   Burn injury occurs when skin is exposed to more energy than it can absorb.  The skin, consists of two layers: the epidermis and the dermis.  The skin is the largest organ of the body and acts as an infection barrier, vapor barrier, and a heat regulator. Pathophysiolo  Three zones of tissue damage occur at the burn site. gy   First is the central zone of coagulation, an area of irreversible damage.  Concentrically surrounding this area is the zone of stasis, where capillary and small vessel stasis occurs. Pathophysiolo  The ultimate fate of the burn wound depends on resolution or gy progression of the zone of stasis.  The third zone of damage is the zone of hyperemia, an area of superficial damage that heals quickly on its own   A brief decrease in blood flow to the affected area is followed by a marked increase in arteriolar vasodilation. Pathophysiolo  Damaged tissues release mediators that initiate an inflammatory response. gy  Release of proinflammatory mediators combined with vasodilation causes increased capillary permeability, leading to intravascular fluid loss and wound edema.   For burn injuries less than 20% TBSA, these actions are usually limited to the burn site.  As the affected TBSA goes beyond 20%, local response becomes systemic (ARDS, SIRS, MODS). Pathophysiolo  Large burns cause a hypermetabolic state that has multiple harmful gy physiologic derangements associated with it (muscle catabolism, hepatic dysfunction, & immunosuppression).  Tight glycemic control and beta blockade may be used to attenuate the hypermetabolic state   Basal metabolic rate increases from insensible fluid loss, which, along with fluid shift, produces hypovolemia.  Hypoproteinemia resulting from increased capillary permeability aggravates edema in non-burned tissue. Pathophysiolo  Capillary permeability increases for 2 to 3 weeks with the most significant changes occurring in the first 24 to 36 hours. gy  Initially blood viscosity increases when hematocrit rises secondary to vascular fluid shifts.  Because of a marked increase in peripheral vascular resistance, decreased intravascular fluid volume, and increased blood viscosity, cardiac output falls.  Decreased circulating plasma with increased hematocrit can cause hemoglobinuria, which can lead to renal failure. Pulmonary  Inhalation injury or smoke inhalation is a  syndrome comprising three distinct problems: Response to  ❖Carbon monoxide intoxication, Smoke  ❖Upper airway obstruction, & Inhalation  ❖Chemical injury to the lower airways and lung parenchyma.   Majority of deaths from fires are due to smoke inhalation rather than the burn injury or its sequelae. Pulmonary  In the body, carbon monoxide has a 240-times greater affinity for hemoglobin than oxygen. Response to  Carbon monoxide combines with myoglobin in muscle cells, Smoke causing muscle weakness.  Carbon monoxide poisoning is characterized by pink to cherry-red Inhalation skin, tachypnea, tachycardia, headache, dizziness, and nausea.   An arterial blood gas sample is drawn to measure the Pulmonary carboxyhemoglobin level. Response to  ❖Levels below 15% are rarely associated with Smoke  symptoms (N for a heavy smoker). Inhalation  ❖Levels of 15% to 40% are associated with  varying disturbances such as headache and confusion.  ❖Levels greater than 40% are associated with coma.   Most pulse oximeters cannot differentiate between oxygenated hemoglobin and hemoglobin with carbon and will give a false high measurement. Pulmonary  All patients with suspected carbon monoxide poisoning should be Response to placed on 100% oxygen. Smoke  Cyanide poisoning may also occur during a fire and can rapidly result in death. Inhalation  Can be formed in high-temperature combustion from materials such as polyurethane, acrylonitrile, wool, cotton, and nylon.   The patient with cyanide poisoning will rapidly develop coma, apnea, cardiac dysfunction, and severe lactic acidosis. Pulmonary  Thermal injury to the upper airway is usually associated with Response to facial burns. Smoke  Upper airway obstruction is the result of intrinsic or extrinsic edema that may lead to airway occlusion at or above the vocal Inhalation cords.  Management for airway edema is early intubation or tracheostomy if intubation is not possible. Pulmonary Response to  Actual thermal injury below the vocal cords is rare because the Smoke posterior pharynx is such an efficient heat exchange system. Inhalation  True thermal injury to the lungs is almost always fatal.   A high index of suspicion for smoke inhalation is essential for burn patients.  Burns that occur in small spaces are often associated with smoke inhalation.  Administration of high-flow oxygen should be started. Management  If the patient has a history of COPD and is a suspected carbon dioxide retainer, immediate intubation is recommended to prevent progressive carbon dioxide retention.   The half-life of carboxyhemoglobin on room air is approximately 240 minutes.  When the patient is placed on 100% FiO , the half-life is reduced to approximately 75 to 80 minutes. Management  Hyperbaric oxygen at 2.0 atm decreases the half- life of carboxyhemoglobin to approximately 20 minutes and appears to hasten the resolution of symptoms.   The use of hyperbaric oxygen in the treatment of carbon monoxide poisoning is controversial.  Circumferential full-thickness burns of the chest can impair breathing by limiting chest wall excursion and preventing adequate gas exchange. Management  Escharotomy is indicated for circumferential burns that compromise breathing.   Improvement in chest wall expansion should occur immediately Management after incisions are made.   General anesthesia is not required because the incisions are made in a full-thickness burn.  Intravenous (IV) narcotic analgesia is usually adequate to relieve any pain associated with escharotomy.  Carboxyhemoglobin level and chest radiograph are obtained to assess for carbon monoxide poisoning.  High-flow oxygen with a nonrebreather mask or bag-mask device Management is administered as appropriate.  If the patient does not respond after 1 to 11⁄2 hours of regular oxygen therapy, hyperbaric oxygen therapy may be used.   Treatment of ARDS if developed includes intubation and ventilation with positive end- expiratory pressure (PEEP).  Giving corticosteroids to patients with burns and smoke inhalation can increase morbidity and mortality. Management  The patient with a burn injury is at significant risk for hypovolemia from actual fluid loss and fluid movement from increased capillary permeability and vasodilation.   Additional indications of volume compromise  include  ❖Central venous pressure less than 3 cm H O,  ❖Hematocrit greater than 50 mg/dL,  ❖Presence of an ileus, & Management  ❖Urine output less than 0.5 mL/kg/hr.  One or two large-bore IV catheters should be started.  Leg veins are avoided because of increased risk for thrombophlebitis. Management  Fluid volume requirements are calculated using an accepted formula such as the Parkland or Baxter formula.   No formula exists for calculating fluid resuscitation in electrical injuries.  An infusion of lactated Ringer’s solution is administered at 1 to 2 L/hr in the average adult until he or she shows signs of adequate resuscitation.  Urine output should be maintained at two to three times the normal Management volume to facilitate excretion of myoglobin.  An osmotic diuretic such as mannitol may be given to increase urine flow and aid in excretion of myoglobin.   All clothing and jewelry should be removed.  The patient with a burn injury has lost the greatest protection against invasion by various pathogensand must be protected with scrupulous aseptic technique.  Intravenous opioid administration should be the prime treatment for burn Management pain.  The opioid of choice has been IV morphine at 25 to 50 mcg/kg/hr, titrating to avoid respiratory depression.  Anxiolytics may help decrease anxiety and improve pain tolerance.   Wound care should be delayed until the patient’s condition is stabilized  Because burn tissue does not stretch, swelling beneath burned Wound Care tissue compromises circulation because of lack of elasticity.  If the patient has signs of compromise, escharotomy is indicated.   After the procedure is completed, a topical antibacterial agent is applied to the open wound, a light pressure dressing is applied, and the extremity is slightly elevated.  Thermal burns are cleaned with mild soap and water. Wound Care  Ruptured blisters should be removed, but intact blisters may be left alone and should never be aspirated with a needle because this increases the chance of infection.   The wound is covered immediately with a topical antibacterial agent such as silver sulfadiazine (Silvadene) or bacitracin.  Burns of the face should be left open and covered by a topical antibiotic ointment such as bacitracin, which is reapplied every 6 hours after gently washing the skin. Wound Care  Chemical burns should be immediately irrigated with tap water or normal saline for at least 5 to 10 minutes to remove the chemical.   If the chemical is dry, it can be brushed from the patient before irrigating.  After the wound is thoroughly irrigated, it is treated like a thermal burn.  In electrical burns, massive muscle injury may be present beneath normal-looking skin or minor to severe exit wounds. Wound Care  Wounds should be cleaned gently with a 0.25% povidone-iodine solution using sterile water or 0.9% sodium chloride   Electrical injuries of the extremities cause tissue swelling. Consequently, these patients are at risk for compartment syndrome.  The patient with a burn injury has lost a major control mechanism for temperature regulation.  Heat loss is worsened by  ❖Administration of room temperature IV fluids, Wound Care  ❖Irrigation of burned tissue, &  ❖Environmental coolness often encountered in the ED. QUESTIONS???? Spinal Trauma   The vast majority of spinal cord injuries are for males under age 38 years. Introduction  MVC is the most common Mechanism of injury.  In older adults, falls are the leading cause of trauma. The cervical vertebrae are the most frequently injured vertebrae (most mobile, small, delicate). Anatomy & Physiology Anatomy & Physiology  ❖ 31 pairs Anatomy & ❖8 cervical nerves, 12 thoracic Physiology nerves, 5 lumbar nerves, 5 sacral nerves, and 1 coccygeal nerve.   All patients with multi-system injuries or significant MOI must be suspected of having a spinal injury and should be completely immobilized. Patient  Spinal protection involves: ❖ Manual immobilization with hands Assessment ❖ With cervical collar  ❖Lateral head support such as head blocks or rolled sheets Patient Assessment ❖backboard The entire spine should be immobilized using a backboard with straps across the chest, abdomen, and knees.   Commonly associated MOIs with cervical spine injuries: ✓Fall from a height greater than or equal to 3 feet or five stairs; ✓ Axial loading; ✓Motor vehicle collision at a high rate of speed with rollover or Mechanisms of ejection; Injury ✓Collision involving a motorized recreational vehicle; and ✓Bicycle collisions. ✓spinal injuries should be suspected if : ✓a fall results in fractures of the heels, or ✓if an unrestrained (no seat belt) patient presents with facial injuries.   Pieces of history that may indicate a potential spinal cord injury ▪ Significant trauma and altered mental status from intoxication; ▪ Seizure activity since the incident; ▪ Any complaint of neck pain or altered sensation in the upper History extremities; ▪ Neck tenderness; ▪ Loss of consciousness; ▪ Injuries to the head or face. ▪ Incontinence before arrival in the ED   Obvious signs of spinal injury include:  Deformity of the vertebral column,  Cervical edema, and Inspection  Ballistic wounds in the neck, chest, or abdomen.  Abrasions or contusions at the level of the lap or shoulder belt in restrained patients   Injuries between C3 and C5 can result in progressive respiratory insufficiency (diaphragmatic innervation by the phrenic nerve)  Injuries to the cord below C5 lead to decreased intercostal Inspection and abdominal muscle function  Priapism (penile erection) indicates a cervical spine injury (loss of sympathetic nervous system control)  patients with CSF leaks raise suspicion for serious spinal trauma.   A patient with a spinal cord injury becomes poikilothermic (assuming the temperature of his or her surroundings) Palpation  In neurogenic shock the pulse is slow and strong, whereas in hypovolemic shock it is rapid and weak.  With sacral sparing an incomplete spinal cord injury should be suspected.  Biceps (tests C5-C6) Reflex Testing Anal wink (tests S2- S4)   Cervical spine & all seven cervical vertebrae, including the C7-T1 junction,  Patients with a history of a fall or significant chest and abdominal trauma should have thoracic and lumbosacral spine films Radiographic  Patients with an altered mental status require complete spinal Evaluation radiographic evaluation.  CT scan is used when C7 to T1 cannot be visualized on plain films   Patients with cervical spine trauma is at risk for hypoxia, respiratory arrest, and aspiration.  Localized edema can cause airway obstruction.  Endotracheal intubation should be considered early in patients with injuries at the C5 level or above. Airway  Cervical Spine Protection: Management  The equipment includes  a rigid cervical collar,  lateral head immobilizer, and  full backboard with straps.   Patients may experience hypotension as a result of neurogenic or hypovolemic shock.  Injuries at T6 or above may cause loss of sympathetic tone, leading to hypotension and bradycardia. Circulation  Pharmacologic Management Management  Methylprednisolone (MP) may be administered. Within 8 hours of injury [↓ edema to the spinal cord, ↓ ischemia, and prevent cellular death].   Unstable cervical fractures may initially be stabilized in the ED with application of cervical tongs or halo devices to provide consistent traction and minimize cord compression. Cervical Tongs and Skeletal halo device Fixation Cervical tongs   Injuries of the vertebral column may occur with or without associated spinal cord injury. Common  When they do occur, spinal cord transections may be complete or fractures of the incomplete. vertebral  Complete spinal cord transections lead to loss of all motor and sensory function below the level of an injury (account for almost column 50% of all spinal cord injuries).   Patients with incomplete spinal cord transections will have Common partial preservation of some motor and/or sensory tracts. fractures of the  Due to decreased mobility from spinal injuries, all spinal cord injury patients are at risk for vertebral  Deep venous thrombosis, column  Decubitus ulcers, and  Pulmonary emboli.   Spinal shock is the loss of reflexes and motor and sensory function below the level of the injury (complete spinal cord injury).  Characteristics, Spinal and  Immediate onset  Flaccid paralysis, Neurogenic  Areflexia, Shock  Bowel or bladder dysfunction, and  Loss of ability to thermoregulate the body (poikilothermic ).  Neurogenic shock usually seen with injuries above the T6 level.  Characterized by hypotension and bradycardia   Patients with incomplete spinal cord injuries have ❖Asymmetric reflexes ❖Flaccid paralysis Incomplete ❖Some preserved sensations below the level of their injury Spinal Cord Injury  Types of incomplete spinal cord injury are: central cord syndrome, anterior cord syndrome, posterior cord syndrome, Brown-Séquard syndrome, and nerve root injuries.  ❖Caused by hyperextension ❖Results in swelling to the central portion of the spinal cord. Central Cord ❖Causes greater loss of function in the upper extremities than in the Syndrome lower extremities. ❖Bowel and bladder function typically are maintained.  ❖Usually results from disruption of the anterior spinal artery (which supplies the motor and sensory pathways in the anterior portion of the spinal cord). ❖Loss of motor function and pain and temperature sensations below the level of the injury. Anterior ❖Vibratory sense, touch, pressure, and proprioception remain intact because the posterior column is preserved. &Posterior Cord ❖Posterior Cord Syndrome Syndrome  Rare  Results from hyperextension injuries that damage the dorsal column of the spinal cord.  Light touch and proprioception are impaired but not completely lost.  ❖Uncommon ❖Results from hemi section of the cord (e.g., gunshot, knife) Brown- ❖Ipsilateral (same side) paresis or hemiplegia and loss of motor Séquard function, touch, pressure, vibratory sense, and proprioception. ❖Contralateral (opposite side) loss or decreased sensation of pain Syndrome and temperature.  ❖Include conus medullaris (at T12) and cauda equina (below L1) syndromes. ❖Result from nerve root compression (vertebral fractures or disk herniation). Nerve Root ❖In both syndromes the patient loses anal sphincter tone. Injuries  Penetrating Injuries: The emergency nurse should leave the object in place and stabilize it.   Is a complication of spinal cord injury above the T6 level that can occur anytime following the resolution of spinal shock.  This life-threatening emergency: occurs when stimulation of the sympathetic nervous system leads to a massive, uncontrolled CV response.  Commonly a full bowel or bladder is responsible for triggering the response (sometimes pain). Autonomic  S & S include  Sudden severe headache, Hypertension, Nausea, Bradycardia. Dysreflexia  Sweating above the level of injury with coolness below the level of injury.  The patient may also complain of nasal stuffiness and appear quite anxious  Treatment is by removing the cause (emptying the bladder, relieving constipation, …etc). QUESTIONS???? Thoracic Trauma  Mortality rates for thoracic trauma are second after brain and spinal Introduction cord injuries.   The focused assessment sonography for trauma (FAST) examination has become an integral component of the initial Patient assessment for patients with both blunt and penetrating trauma to Assessment the thorax and/or abdomen.  The sensitivity of the FAST examination for detecting blood in the pericardial space has been reported at 96% to 100%   Occur most often in the fourth through tenth ribs. Rib Fractures Fractures that separate the sternum from costal cartilage are not evident on a radiograph.   Fractures of the first and second ribs are rare due to the protection granted to them by the clavicle.  Significant blunt force is required to fracture these ribs.  Patients with multiple rib fractures are usually admitted for observation.  Those with severe injuries (eight or more fractured ribs, massive Rib Fractures flail injury) may require internal fixation with plates and screws.  Children have thin chest walls, and their bony thorax is more cartilaginous (difficult to fracture).  When rib fractures do occur in children, concurrent thoracic and abdominal injuries may be severe.    A flail chest is defined as fractures in two or more adjacent ribs in two or more places, or bilateral detachment of the sternum from costal cartilage.  A flail chest creates a free-floating, unstable segment that moves in opposition to normal chest wall movement. Flail Chest  The loss of coordinated chest wall movement results in hypoventilation of both lungs followed by atelectasis and eventually hypoxia. Usually associated with an underlying pulmonary contusion     Paradoxical chest wall movement will not be demonstrated in the mechanically ventilated patient.  Treatment consists of  ❖ensuring adequate oxygenation,  ❖judicious fluid administration, & Flail Chest  ❖pain management.     Sternal fractures occur when tremendous force is applied to the chest, as with steering wheel impact.  The most common site of fracture is the junction of the manubrium and body of the sternum (angle of Louis). Sternal  Sternal fracture has significant potential for underlying cardiac and Fracture pulmonary injury, including pulmonary contusion, blunt cardiac injury, and pericardial tamponade  Treatment includes  ❖pain relief  ❖a baseline ECG to evaluate potential blunt cardiac injury, &  ❖serial patient examinations.   Fracture of the larynx is a rare, life-threatening injury.  S&S  ❖hoarseness, Laryngeal  ❖stridor,  ❖hematoma, Injury  ❖ecchymosis,  ❖laryngeal tenderness,  ❖subcutaneous emphysema,  ❖crepitus, or loss of anatomic landmarks.   Any patient with a laryngeal injury must be evaluated for a concomitant cervical injury, and patients with cervical injury need to be assessed for laryngeal injury. Laryngeal  Intubation may worsen the preexisting injury (laceration or tracheal Injury separation may occur during tube placement).  Tracheostomy is indicated for the patient in respiratory distress and will be left in place for at least 5 days.   Accumulation of air in the pleural space resulting in partial or complete collapse of the lung as negative intrapleural pressure is lost.  Laceration of lung tissue, often associated with rib fractures and subsequent Pneumothorax air leak, is the most common cause of pneumothorax with blunt trauma.  S & S include  ❖Chest pain  ❖SOB  ❖decreased or absent breath sounds (on affected side)  ❖Tachycardia and tachypnea  Chest tube insertion is generally required for moderate to large pneumothoraxes.  The chest tube is most commonly placed in the fourth or fifth intercostal space, along the anterior axillary line.  https://www.youtube.com/watch?v=69A6mdtfSek&rco=1    Open pneumothorax (sucking chest wound) occurs when an opening in the chest is more than two thirds the diameter of the trachea.  An open chest wound causes loss of the negative intrathoracic Open pressure. Pneumothorax  In sucking chest wound, lung volume is greater  with expiration (Lt + Rt).     Bubbles or froth often is observed around the wound as air escapes through the bloodied wound.  Immediate treatment consists of placing a sterile, nonporous, three- sided occlusive dressing over the injury. A chest tube should be Open inserted to facilitate re-expansion of the lung. Pneumothorax  Definitive treatment of the open chest wound is operative closure.  If the injury is caused by penetrating trauma with an impaled object, the object must be stabilized and left in place.  NEVER REMOVE the object in the emergency department (ED).  life-threatening condition occurs when accumulation of air in one pleural space forces thoracic contents to the opposite side of the chest.  Tension Pneumothorax Immediate needle decompression of the affected side is required. A 14- or 16-gauge catheter is inserted into the second intercostal space at the midclavicular line on the injured side.   A hemothorax is free blood in the pleural space  The most common cause is an injury to the intercostal arteries that results in bleeding into the pleural space.  Treatment …. Chest tube insertion Hemothorax  If blood return with chest tube insertion is 1000 mL or blood loss is 200 mL/hr for 3 to 4 hours, surgical intervention is indicated     75% of patients with blunt chest trauma have an underlying pulmonary contusion, with mortality about 40%. Injury to lung parenchyma worsens progressively over time. Pulmonary  Thoracic injuries associated with pulmonary contusion include rib Contusion fractures, flail chest, hemothorax, pneumothorax, and scapular fractures    Injury to the lung parenchyma causes ruptures and hemorrhages into pulmonary tissue, alveoli, and small airways. ↓↓  airways collapse, followed by loss of ventilation, pulmonary shunting, and hypoxemia.  50% of patients with pulmonary contusion have no external physical findings. Pulmonary  Contusions change rapidly and usually improve within 72 hours and resolve within 3 to 5 days. Contusion   Lateral impact from an MVC is three times more likely than any other type of impact to cause a rupture.Most injuries occur on the left side of the diaphragm; the reason for this is unclear, but the proximity of the right diaphragm to the liver may provide protection.  If abdominal herniation occurs, it can cause significant lung Diaphragmatic compression, leading to tension pneumothorax. Injury  S & S include ❖Dyspnea ❖abdominal or epigastric pain that radiates to the left shoulder (Kehr’s sign)❖bowel sounds in the chest ❖decreased breath sounds on the affected side Diaphragmatic Injury  The chest radiograph may demonstrate ❖an elevated diaphragm, ❖loss of the diaphragmatic shadow, ❖irregularity of the diaphragm, or even Diaphragmatic Injury ❖a gastric tube noted to pass into the stomach and then curling into the chest. In the stable patient, the CT scan of the chest is the diagnostic tool of choice. If a DPL is performed, lavage fluid may leak into the chest drainage system, if present.   Formerly known as “cardiac contusion” or “cardiac concussion,”  An echocardiogram differentiates the extent of injury.  Extensive myocardial injury is characterized by 12-lead ECG changes, dysrhythmias, and some evidence of myocardial dysfunction on the echocardiogram.  S & S are nonspecific (range from asymptomatic Blunt Cardiac  to cardiogenic shock). Injury  Dysrhythmias associated with this injury include  ❖sinus tachycardia, atrial fibrillation/flutter, atrial and ventricular extrasystoles, and even ventricular tachycardia/fibrillation.  ❖The most common dysrhythmia is premature ventricular contractions (Complexes is more accurate).  Treatment consists of cardiac monitoring of patients for at least 24 hours.    Most victims arrive in the ED in cardiac arrest or with significant hypotension secondary to cardiac tamponade or hemorrhage. Penetrating  The right ventricle is the most frequently injured chamber because of its Cardiac Injuries anterior position  Penetrating injuries are associated with a high mortality (83%).   Occurs when rapid accumulation of blood in the pericardial sac decreases ventricular filling. Signs of cardiac tamponade are called Beck’s triad: hypotension, muffled heart tones, and distended neck veins Cardiac Pericardiocentesis may be lifesaving for some Tamponade patients with pericardial tamponade. Pericardiocentesis for acute cardiac tamponad can be performed via a left subxiphoid or parasternal approach.  Some patients exhibit an unusual rhythm known as electrical alternans Cardiac Tamponade   The majority of victims with aortic rupture die at the scene  The most common sites of injury involves ❖ The area of the aorta just Aortic distal to the left subclavian artery adjacent to the ligamentum arteriosum Disruption (the site where the aorta is relatively fixed in place).  ❖ The innominate artery at the aortic arch and  ❖ The aortic valve Aortic Disruption Common sites of aortic disruption.   A discrepancy between blood pressure values in the right and left arms may occur, depending on the level of aortic injury.  Blood pressure and pulse quality in the upper extremities are elevated, whereas pulses and blood pressure in the lower extremities are decreased or Aortic absent.  Disruption The most common diagnostic test is a chest radiograph; the most common finding is mediastinal widening  Definitive treatment is immediate surgical repair.   Injury to the esophagus is rare and often lethal Instrumentation during invasive procedures such as endoscopy or intubation is the most common cause. Regardless of the mechanism, the final result is mediastinitis caused by contamination from saliva and gastric contents. Esophageal Chest tube drainage may contain particulate matter. Injury Urgent surgical repair is indicated. QUESTIONS???? Head Trauma   Traumatic brain injury (TBI) is a leading cause of death and Introduction permanent disability. A small percentage of patients with severe TBI will have concomitant fracture of the cervical spine.   The skull is divided into the supratentorial and the infratentorial Anatomy and space. The cerebral hemispheres and the diencephalon are contained Physiology in the supratentorial space.  The infratentorial space contains the cerebellum and the brainstem.   Any trauma to the  1. Scalp 2. Skull 3. Brain  Includes an alteration in consciousness, no matter how brief.  Causes: Head Trauma  Firearm-related injuries sites and  Motor vehicle accidents Causes  Falls  Assaults  Sports-related injuries  Recreational accidents Specific Injuries classifications   Mild Injury Specific  GCS, 14 to 15 Evaluated and treated in the ED and may be Injuries discharged home after a short period of observation. Are associated classifications with structural damage (e.g., contusions)   Moderate Injury GCS, 9 to13 Are associated with structural Specific damage (e.g.,contusions).Have a high potential for deterioration Injuries because of ↑ cerebral edema and ICP. Require frequent neurologic classifications assessments and ahigh index of suspicion for potential deterioration.   Severe Injury Specific  GCS < = 8 Often associated with significant structural damage, Have high mortality rate. Patients who survive frequently have Injuries long-term or permanent cognitive and physical disabilities. Require classifications Aggressive management (oxygenation and prevention of hypotension) to prevent secondary brain injury.   Scalp Lacerations:  The scalp has an extensive vascular supply with poor Specific Injuries vasoconstrictive properties, causing lacerations to bleed profusely. classifications types of injury “Focal injury”  A linear skull fracture is nondisplaced and associated with minimal neurologic deficit.Supportive care is usually all that is required for optimal neurologic recovery.   Depressed skull fracture :requires surgical elevation when Focal Injuries depressed bone fragments become lodged in brain tissue.   Basilar skull fracture: Approximately 25% of basilar skull fractures are not seen on radiographs.Disruption of the middle meningeal artery is the cause of more than 75% of epidural Basilar skull fracture: hematomas. A basilar skull fracture may also cause intracerebral bleeding.  Combative behavior is often considered ahallmark of a basilar skull fracture.  1. Battle’s sign(ecchymosis over the mastoid process)12 to 24hours Basilar skull fracture: after initial injury. clinical manifestations 2. Periorbital ecchymoses (raccoon eyes) from intra-orbital bleeding   3. Hemotympanum(blood behind the tympanic membrane caused by a fracture of the temporal bone).  4. CSF leak from the nose or ear caused by temporal bone fracture. Basilar skull fracture: Nasal packing is not recommended. clinical manifestations  CSF or nasal discharge ?!+ ve “halo” or “ring” sign indicates presence of CSF. Clear fluid should be tested for glucose, a normal finding in CSF.   Cerebral contusion is a bruise on the surface of the brain. CONTUSON   When an acceleration-deceleration injury occurs, two contusions may result, one at the initial site of impact (coup) and one on the CONTUSON opposite side of the impact (contrecoup).Commonly occurring symptoms include altered level of consciousness, nausea, vomiting, visual disturbances, weakness, and speech difficulty.   Interventions focus on preservation of neurologic function, control of pain, adequate hydration, admission and serial neurologic CONTUSON assessments. Some neurosurgeons may elect to surgically evacuate the contusion and leave the bone flap off to allow for swelling of the brain. Focal Injuries  Bleeding between the skull and dura mater.A skull fracture and \ Epidural injury to the middle meningeal artery may also be present(morbidity Hematoma and mortality > 50%).   Bleeding between the skull and dura mater.A skull fracture and injury to the middle meningeal artery may also be present(morbidity Focal Injuries and mortality > 50%). \ Epidural Hematoma  S & S include a brief period of unconsciousness followed by a lucid period (hallmark), then another loss of consciousness. Large epidural hematomas require emergent surgical evacuation   more frequent than other intracranial injuries and have the highest Focal Injuries morbidity and mortality of all hematomas. May be acute, subacute, \ Subdural or chronic. Acute subdural hematoma results from rupturing the Hematoma bridging veins in the subdural space.   Clinical features are loss of consciousness; hemiparesis; and fixed, dilated pupils. Surgical intervention within 4 hours of injury has the best potential for neurologic recovery. Subacute subdural Focal Injuries hematomas develop 48 hours to 2 weeks after injury. The clinical \ Subdural presentationism progressive decline in level of consciousness asthe Hematoma hematoma slowly expands.  Chronic subdural hematomas, seen more frequently in older adults, progress slowly (weeks to months). Intraventricu lar hemorrhage  Surgical evacuation may be necessary in concert with medical and management of increased. intracerebral clots Diffuse Brain Injuries\ Mild  The brain collides with the inside of the skull.It is now known that TraumaticBr there is some degree ofneurochemical as well as axonal ain Injury disruptionassociated with MTBI,An MTBI may be associated with (MTBI, cognitive,physical, emotional, and sleep disturbances. Concussion) Diffuse Brain  Brain Injury (MTBI, Concussion)Acutely, it is typically associated Injuries\ Mild with a loss of consciousness followed by transient neurologic Traumatic changes such as nausea, vomiting, temporary amnesia, headache, Brain Injury and possible brief loss ofvision.Patients should not return to sports, (MTBI, work, school, or engage in high-risk activities until allsymptoms of Concussion) the brain injury are gone. Diffuse Brain Injuries\ Mild  Diffuse Brain Injuries\ Diffuse Axonal Injury.The most severe form Traumatic of TBI.Almost always the result of blunt trauma that causes Brain Injury shearing and disruption of neuronal structures, predominantly white (MTBI, matter. Concussion)   In the adult patient the skull is a closed box containing three volumes: the brain (80%),CSF (10%), and blood (10%).  Intracranial pressure (ICP) reflects the pressure in the supratentorial space as exerted by the total of the three volumes, Normal ICP is less than 10 mm Hg with an upper limit of approximately 15 mm Hg. ICP  When the ICP increases, and if not immediately corrected, it will compromise cerebral blood flow. Failure to reduce ICP may cause ischemia and necrosis of brain tissue.  Cushing’s Triad (↑ ICP):1. Systolic hypertension with increased pulsepressure2. Bradycardia3. Bradypnea (↓ respiratory rate). If ↑ ICP not treated, herniation occurs   Cerebral autoregulation is the ability of the brain into maintain a constant blood flow over a wide range of metabolic demands and systemic mean arterial pressures (normally 50 to 150 mm Hg). CPP  This is accomplished through vasoconstriction or vasodilation of the cerebral blood vessels. When cerebral autoregulation is disrupted, cerebral blood flow becomes dependent on the systemic blood pressure.   Cerebral perfusion pressure (CPP) is the pressure difference between the arterial blood entering the brain and the venous blood CPP exiting (CPP ≥50 mmHg).  CPP = MAP – ICP Blood pressure that is decreased with brain injuries indicates a poor prognosis.   Level of conscious deteriorates: Patient may become, restless, more confused, agitated or combative Sings &  Headache, Nausea/vomiting, Slowed or slurred speech, Blurred symptoms of vision or diplopia. increased ICP: Early signs  Pupillary changes: Delayed/sluggish reactivity to light, pupil becomes ovoid, unilateral change in pupil size or shape, Decreased strength and sensation.  Progressive decline in level of consciousness tocoma. Projectile vomiting (without nausea). Speech significantly impaired, may only groan. Impaired brainstem reflexes (corneal, gag). Motor posturing. Sings & symptoms of increased ICP: Late signs Unilateral or bilateral pupil that enlarges and becomes fixed. Irregular respirations. Cushing’s response. Cardiac dysrhythmias. Abnormal reflexes (Babinski’s).   In the acute resuscitation a GCS score of 8 or less represents coma. Sluggish pupillary response may be the first indication of increasing Patient cerebral edema and rising ICP. An oval pupil is also commonly Assessment seen in patients with increasing ICP If ICP cannot be controlled, the pupil will become dilated and nonreactive.   Bilateral fixed and dilated pupils are indicative ofimpending transtentorial herniation.  The oculomotor (CN III), trochlear (CN IV), and abducens (CN VI) nerves control Patient extraocular eye movements. If any of the three CNs are injured, there will be Assessment paralysis or paresis of the extraocular muscles ,leading to a disconjugate gaze.  Ptosis (drooping eyelid) may also be observed with injury to the oculomotor nerve.   The oculocephalic (doll’s eye) reflex tests the integrity of pontine centers (brainstem).Loss of brainstem integrity is presumed when eyes remain midline with rotation of the head or move in adisconjugate manner. Patient Assessment  There are a variety of cardiac dysrhythmias associated with traumatic brain injuries.  Bundle branch blocks and atrial fibrillation may be seen with contusions, atrial and ventricular ectopy with subdural hematomas, and ST and T-wave changes with severe brain injuries.   Patients with severe brain injury likely benefit from early intubation and targeted ventilation. Patients with a GCS < 8, require endotracheal intubation (protect airway, ↓ risk of aspiration, Patient adequate ventilation).Maintaining systolic blood pressure > 90 mm Management Hg to ensure adequate CPP. Hypotonic solutions should be avoided because they can potentiate cerebral edema.  The primary radiographic study for the evaluation of brain injury in the ED phase of care is the computed tomography (CT) scan.   Hyperventilation↓ ICP by vasoconstriction (cerebral vessels), which decreased cerebral blood flow and ultimately cerebral volume. Numerous studies have now concluded that hyperventilation can actually be more detrimental. Hyperventilation may be used as a temporizing measure only (keep PaCO2 > = 30 Patient mm Hg). Management  Hyperosmolar therapy primarily reduce the ICP by creating an osmotic gradient that pulls water from cerebral tissue into the vascular space. Mannitol (0.25 to 1 g/kg bolus doses) has been widely used as a method to control ICP. hypertonic saline in various strengths (3%, 7.5%,and 10%) can also be used.   Invasive monitoring of ↑ICP is required when:  Abnormal admission CT scan with GCS ≤8.  If the CT is normal, presence of 2 or more of the following:- Age > 40- Abnormal motor posturing- Systolic blood pressure < 90 mm Hg. Patient  Scientific evidence indicates that maintaining ICP below 20 mm Hg Management improves outcomes. Treatment should be initiated when ICP is greater than 20 mm Hg for more than 5 minutes.  Sedation (benzodiazepines and opioid) are first line agents to:  Minimizing the noxious effects of endotracheal intubation and other stimuli,  Pain, Control ICP   Maintain cerebral perfusion between 50 mm Hg and 70 mm Vasopressors are widely used to augment systemic blood pressure and MAP and thus improve CPP.Maintaining hematocrit level at 30% to 35% and administration of blood products improves oxygen delivery.  Paralytic agents can also be used in conjunction with sedatives and Patient analgesics to↓skeletal muscle activity ↓metabolic rate, and oxygen Management consumption. Early seizure activity should be treated with appropriate anticonvulsants.  If cervical spine injury has been ruled out and the patient is hemodynamically stable, elevate the head of the bed 30 to 45 degrees, which may↓ICP.Maintaining the head in neutral alignment also facilitates venous drainage (↓ICP). QUESTIONS???? Mechanism of Injury  Infants (75 years): years of age have the highest death rate from injuries, due to their frailer state of health and pre-existing Elderly (>65 years): 12-14 times more likely to sustain cervical spine injuries compared to pediatric patients   Mechanism of Injury is the study how energy is transferred from environment to the individual.  Important to: Mechanism of  Anticipate injuries, diagnosis, treatments, and complications of Injury traumatic injury.  Understand the populations who are at risk for particular injuries.   Injury, defined as trauma or damage to a part of the body, occurs when an uncontrolled or acute source of energy makes contact with the body and the body cannot tolerate exposure to it.  Energy originates from numerous sources, including: “kinetic Injury (motion or mechanical),“ chemical,“ electrical,“ thermal,“ Radiation, and“ Absence of heat and oxygen causes injuries such as frostbite, drowning, or suffocation.   Kinetic energy results from motion. The majority of traumatic Injury injuries are caused by absorption of Kinetic energy. Mechanism of Injury:  Essential Concepts: Essential  Acceleration :Increase in velocity or speed of a moving object. Concepts:  Deceleration: Decrease in velocity or speed of a moving object. Mechanism of  Acceleration-deceleration: Increase in velocity or speed of object Injury: followed by decrease in velocity or speed. Essential  Axial loading Injury :occurs when force is applied upward and Concepts: downward with no posterior or lateral bending of the neck. Mechanism of  Cavitation: Creation of temporary cavity as tissues are stretched Injury: and compressed. Essential  Force: Physical factor that changes motion of body at rest or Concepts: already in motion.  Inertial resistance : Ability of body to resist movement.   Injury :Trauma or damage to some part of the body. Mechanism of  Kinematics :Process of looking at an accident and determine what Injury: injuries might result. Essential  Muzzle blast :Cloud of hot gas and burning powder at the muzzle of Concepts: gun.  Shearing :Two oppositely directed parallel forces.   Kinematics is the process of looking at an event and determining what injuries are likely to occur given the forces and motion involved.  Physics is the foundation on which kinematics is based. Kinematics  Essential Laws of Physics:  1. Newton’s First Law of Motion a body at rest remains at rest and a body in motion remains in motion unless acted on by an outside force. Give examples !   2. Law of Conservation of Energy : energy is neither created nor destroyed but changes form. Give examples !  As a car decelerates slowly, the energy of motion(acceleration) is Kinematics converted to friction heat in braking (thermal energy).  3.Newton’s Second Law force equals mass multiplied by acceleration or deceleration   Initially trauma patients may not appear seriously injured because of strong compensatory mechanisms.Patients, family, and friends may have reasons to fabricate, falsify, or deny the actual event. Patient  Some injuries are significant because of potential complications, Assessment such as two or more long bone fractures; flail chest; penetrating trauma to the head, neck, chest, abdomen, or groin; and any combination of these patterns with burns over the head. face. or airway.   What to ask about Mechanism of Injury ?  What type of vehicle was the patient driving(large or small)? Patient  What was the estimated speed at the time of the crash? Assessment  Were seat belts or restraint devices used?  Were the devices applied appropriately? Were air bags installed, and did they deploy?   Where was the patient in the vehicle (driver, front passenger, or rear-seat passenger)? If ejected, how far was the patient thrown or found f rom the vehicle? Patient  How much damage was done to the vehicle? Where was the Assessment majority of damage?  Was there intrusion into the passenger space? How much?  Was there any steering wheel deformity?   If the patient was involved in a fall, the following questions should be asked: Patient  What was the approximate height of the fall? Assessment  Were any objects struck during the fall’? fall  What was the surface where the patient landed?  In what position was the patient found after the fall?   What was the wounding agent (e.g., knife, gun,arrow, ice pick)? Patient  What was the size and length of the agent? Assessment  If a firearm was used, what was the caliber? penetrating injury  What was the distance between the fired weapon and the patient?  Patients may be exposed to more than one wounding force. Mechanism of  Blunt injury, Injury classification  Penetrating injury   Patients with penetrating trauma are generally easier to assess than those with blunt trauma because injuries are usually focused in one area. Mechanism of  Surface trauma may or may not be present with blunt injuries; Injury therefore assessment tends to be more difficult. classification  Because energy associated with blunt trauma is transmitted m all directions, organs and tissues can rupture or break if pressure is not released   Examples of blunt force events include MVCs,falls, contact sports, Mechanism of and assaults.Before a collision (Accident) the occupant and vehicle Injury a removing at the same speed. At the time of collision the vehicle classification and the occupant decelerate to a speed of zero, but at different rates.   Frontal impact occurs when the front of a vehicle impacts another object (e.g., another vehicle, tree, bridge abutment).After the Frontal impact vehicle stops, occupants in the front seat continue to move down and under, or up and over, the dashboard. Frontal impact Mechanism Injury Description Down and Knees absorb impact energy, leading to patellar Under Knee Impact on dislocations, midshaft Dashboard femur fractures, and acetabulum injuries. Upper legs sustain most of Energy Absorption by the impact, causing Legs posterior dislocations or fractures of the hip joint. Frontal impact Down and Under  Mechanism Injury Description Head injuries, including contusions, scalp lacerations, Up and Over Impact skull/facial fractures, cerebral hemorrhage, or contusions. Brain strikes inside of the skull Frontal impact due to sudden stop after head hits Coup Injury Up and Over a stationary object (e.g., steering wheel). Brain injury on the opposite side of the impact due to recoil or Contrecoup Injury "bounce-back" movement within the skull. Broken windshield with spider Cervical Spine Injury Risk web effect indicates potential cervical spine trauma.  Mechanism Injury Description Acts as a lethal force, causing neck, face, thoracic, or Steering Column Impact abdominal injuries, especially with wheel deformity. Chest wall impact compresses Compression Impact ("Paper lungs against a closed glottis, Frontal impact Bag") causing lung rupture similar to a closed paper bag bursting.  Impact Type Injury Description With side-impact or lateral collisions, occupants generally receive most Lateral or Side Impact injuries on the same side of their body as the vehicle impact. Cont… Sudden acceleration causes hyperextension of the Rear Impact neck, especially if headrests are mispositioned. Injuries can be unpredictable; axial loading Vehicle Rollover injuries are more likely in rollover accidents.  Ejections increase the risk of spinal fractures and traumatic brain injuries, Ejection with ejected occupants having a higher chance of death, especially if unrestrained. Designed to prevent injuries by allowing occupants to decelerate at the same rate Restraint Systems as the vehicle, preventing impacts with interior structures or ejection. Safety belts reduce the risk of fatal Safety Belts injuries by 45% and moderate-to-critical injuries by 50% for front-seat occupants. Airbag deployment can cause facial trauma, bruising, and corneal abrasions. Airbags Drivers and passengers should sit at least 25 cm from the steering column/dashboard.  Description Pedestrian injuries depend on age and size. Adults tend to turn away from impact, while children face the vehicle, often Pedestrian Pedestrian Injuries resulting in frontal impacts Injuries usually occur because children tend to freeze and face the approaching vehicle. A common injury pattern in children struck by a car, Waddell’s Triad including chest, head, and femur injuries. Pedestrian Injuries  Adults struck by a vehicle sustain injuries to the lower extremities along with head, chest, and abdominal injuries. Adults try to protect themselves by turning sideways, so the impacts usually lateral.  Description Injury severity depends on fall height, body area impacted, and surface landed on. Fall Injuries Falls are more likely to result in severe injury when the distance is three times greater than the victim's height Injuries from falling feet first include bilateral calcaneus Don Juan Syndrome fractures, compression fractures in the thoracolumbar spine, and bilateral Colles fractures.  Colles fracture, fracture of the distal radius in the forearm with dorsal (posterior) displacement of the wrist and hand.   Caused by compressive forces or sudden deceleration as well as by twisting, hyperflexion, and hyperextension. Factors that contribute Sports & to injuring events includes: Recreation-  lack of protective equipment Related Injuries Generally  lack of conditioning,  and inadequate training of the participant. Adolescents aged 10-14 have the highest rates of sports- and recreation-related injuries. Collegiate and high school football players with a history of concussion are at higher risk for subsequent concussions.   The extent of damage will be governed by an interaction of three Penetrating factors:(1) The character of the wounding instrument(e.g., knife, Trauma gun, bomb fragment),(2) Its velocity at the time of Impact, and(3) The characteristics of the tissue through which it passes.   Stab wounds are considered low-velocity injuries and therefore low energy transfer.Women tend to stab downward, whereas men tend to stab upward. Stab Wounds  Tissue damage is generally isolated to the area of penetration Injury limited to the pathway of potential penetration   It is important to remember that small wound scan hide extensive internal damage caused by weapon movement. Internal damage is Stab Wounds directly proportional to the length of the wounding object and to the densityof tissue affected.   Impalements are generally low-velocity injuries that occur from falls, MVCs, or secondary to a flying or falling object.Impaled Impalements objects should be stabilized and remove only when the patient is in a controlled environment such as an operating room where surgical support and intervention is immediately available.   Handguns, shotguns, and rifles are responsible for most firearm Gunshot Wounds injuries.   Ballistics is the science of the study of the motion of projectiles.A penetrating wound occurs when the missile remains in the body and Gunshot Wounds there is only an entrance wound a perforating wound occurs when the missile passes out of the body and thus creates an entrance and an exit wound  Note the difference between entrance and exit wounds. Exit wounds are generally longer and more explosive. Gunshot Wounds   Low-velocity missiles travel at speeds below 2500 ft/sec and have little disruptive effect on tissues. Gunshot  High-velocity missiles(HVMs) travel at speeds above2500 ft/sec Wounds and cause more serious injuries because of high cavitation and energy transfer(cavities can be 30 to 40 times. QUESTIONS????