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THE KURSK STATE MEDICAL UNIVERSITY

Department of surgical diseases № 1

THORACIC TRAUMA

Information for self-training of English-speaking students

The chair of surgical diseases N 1 (Chair-head - prof. S.V.Ivanov)

By ass. professor I.S. IVANOV

KURSK-2010

INITIAL MANAGEMENT OF THE ACUTELY INJURED PATIENT

Priorities

Initial care of the injured patient necessitates two assumptions: that the patient may have more than one injury, and that the obvious injury is not necessarily the most important one. Successful resuscitation requires an approach predicated on prioritizing injuries. A simple method of prioritization includes four categories of injury:

1. Exigent—the most life-threatening conditions, requiring instantaneous intervention (e.g., laryngeal fracture with complete upper airway obstruction and tension pneumothorax)

2. Emergency—those conditions requiring immediate intervention, certainly within the first hour (e.g., ongoing hemorrhage and intracranial mass lesions)

3. Urgent—those conditions requiring intervention within the first few hours (e.g., open contaminated fractures, ischemic extremity, and hollow viscous injuries)

4. Deferrable—those conditions that may or may not be immediately apparent but will subsequently require treatment (e.g., urethral disruption and facial fractures)

Use of this scheme requires a deliberate and regimented approach to the resuscitation, while retaining the flexibility to reset the priorities depending on the diagnostic disclosures that arise during the resuscitation. The maintenance of this balance between a structured resuscitation protocol and the need to change direction properly generate the necessity for one person to be in charge of the entire resuscitation procedure.

Steps In The Initial Resuscitation

Airway. The crucial first step in managing an injured patient is securing an adequate airway. The mechanical removal of debris and the chin lift or jaw thrust maneuvers, both of which pull the tongue and oral musculature forward from the pharynx, are often useful in clearing the airway of less severely injured patients. However, if there is any question about the adequacy of the airway, if there is evidence of severe head injury, or if the patient is in profound shock, more definitive airway control is appropriate. In the vast majority of patients this involves endotracheal intubation. Unfortunately, control of the airway is sometimes more complex than simply placing an endotracheal tube. The presence of cervical spine injury in the unconscious patient is always a possibility, and injudicious movement of the neck in the process of endotracheal intubation can be devastating.

Endotracheal intubation, the most direct method for establishing an airway, requires that the head and neck be held in a neutral position to avoid exacerbation of potential cervical spine injury and that the spine be stabilized until an injury has been definitively ruled out. If the patient has no evidence of soft tissue or bony injury to the midface, and is breathing spontaneously, nasotracheal intubation is an acceptable alternative to orotracheal intubation.

In a few patients, a surgical airway may be required. Although classic tracheostomy may be indicated in select patients, such as those with laryngeal injuries, cricothyroidotomy is generally the preferable emergency procedure. These surgical procedures may be preceded by needle cricothyroidotomy with jet insufflation to improve oxygenation and allow the surgical procedure to be performed in a more orderly fashion.

Breathing. If there is decreased respiratory drive or an unstable chest wall, assisted ventilation is usually necessary. The three most common reasons for ineffective ventilation following successful placement of an airway are malposition of the endotracheal tube, pneumothorax, and hemothorax. Therefore, palpation and auscultation of the chest are necessary diagnostic adjuncts at this point. A supine (anteroposterior [AP]) chest x-ray examination can validate the physical examination and better define chest wall and plural abnormalities. Although there is usually time to perform a chest radiograph prior to invasive therapeutic procedures, in the patient with profound hemodynamic instability and a high suspicion of tension pneumothorax, a needle catheter decompression can be both diagnostic and therapeutic. Under these circumstances decompression of the chest before the radiograph is appropriate.

Circulation. When possible, control of the hemorrhage precedes placement of the intravenous lines. This may be as simple as a compressive dressing over a bleeding wound or large vessel or may require broader compression, such as application of a pneumatic antishock garment in the patient who has an obvious pelvic fracture. Intravenous cannulas are usually placed percutaneously in the arm or groin. They should be large bore, and a minimum of two should be placed. Lines should not be inserted distal to extremity wounds with potential vascular injury. Alternatives are cut-down by either the antecubital or saphenous route, or intraosseus in children under the age of 3. With the exception of the use of the large (8 French) introducer catheter, subclavian venipuncture is not a rapid route for fluid administration and is best reserved for monitoring response to fluid therapy. Fluid resuscitation begins with a 1000-ml. bolus of lactated Ringer's solution for an adult, or 20 ml. per kg. for a child. Response to therapy is monitored by skin perfusion, urinary output, and central venous pressure readings when that line has been placed.

Disability/Neurologic Assessment. At this juncture, a brief examination to determine level of consciousness, pupillary response, and movement of extremities is a necessary prelude to the determination of severity of neurologic injury. In addition, this information becomes initial data in the computation of the Glasgow Coma Scale (GCS), which is a method of both following the evolution of neurologic disability and prognosticating future recovery. It is worth noting that pupillary response can still be assessed in the paralyzed patient. In recording the GCS in intubated and paralyzed patients, the authors have added the modifiers T and P (intubated and paralyzed, respectively) to signify that the score may be inaccurate.

Exposure for Complete Examination. By this point, most injuries that are either exigent or emergencies have been recognized and treated. The next step is to completely, but expeditiously, re-examine the patient to diagnose other injuries. Complete physical examination is typically done in a head-to-toe manner and includes ordering and collecting data from appropriate laboratory and radiologic tests. Data accumulated can then be used to reset priorities. This time period also allows for the placement of additional lines, catheters (nasogastric, Foley), and monitoring devices. When the patient is oxygenating, ventilating, and perfusing adequately, a priority plan should be established for subsequent treatment.

RECOGNITION AND MANAGEMENT OF SPECIFIC INJURIES

Management of Specific Injuries

TRACHEA AND LARYNX

Penetrating tracheal wounds are usually readily apparent and dramatic in their clinical presentation, with subcutaneous emphysema, crepitus, or hemoptysis as presenting signs. Early endotracheal intubation by field paramedics may, however, mask a high tracheal injury. Indications for primary surgical repair depend on the severity of the injury; hence, careful endoscopic or surgical evaluation is required. When repair is needed, the principles include dйbridement of devitalized cartilage, mucosal coverage of exposed cartilage, and closure of tracheal defects. Tracheostomy is not always required following a tracheal repair but certainly is useful if extensive edema or prolonged airway compression is anticipated.

Blunt laryngotracheal injuries are not always obvious and are easily overlooked in the multiple trauma victim. These patients may initially appear deceptively normal, only to suddenly develop severe respiratory distress. Physical examination, flexible fiberoptic endoscopy, and CT may help access the neck for blunt laryngotracheal injury. Equipment for emergency tracheostomy must always be readily at hand. If emergency airway is required, direct endotracheal intubation may be attempted if the laryngeal structures are well visualized, aided by passing the endotracheal tube over a flexible endoscope. However, even in the most experienced hands this may be impossible and may risk worsening the tracheal injury. Tracheostomy is therefore usually recommended as an emergency airway following blunt laryngotracheal injuries, even though it also carries risk of further injury. The basic principles of repairing tracheal injuries are primary closure of mucosal lacerations and reduction of cartilaginous fractures. Mucosal repairs should be performed with fine absorbable suture. Simple lacerations of the subglottic trachea can generally be primarily repaired with simple nonabsorbable sutures. If the defect cannot be primarily closed, tracheal mobilization may bridge a gap of several tracheal rings. Controversial areas in the surgical care of laryngotracheal trauma patients include the timing of operation, the role of laryngeal stents, the use of steroids, indications for skin grafting, and the techniques of operative exposure of the larynx.

PHARYNX AND ESOPHAGUS

Injuries to the esophagus are most difficult to diagnose. The sensitivity of esophagography in detecting esophageal injury varies from approximately 50% to 90%; the sensitivity of endoscopy varies from 29% to 83%. 25 These modalities should be considered complementary, and when combined, have an accuracy of nearly 100%. Operative exposure of the esophagus can be difficult. The morbidity and mortality of a missed esophageal injury demands a high index of suspicion, since virtually all reported deaths from cervical esophageal injuries are the result of a delayed or missed diagnosis. When injured, the structures may be repaired primarily in two layers using absorbable and nonabsorbable suture. It is important to drain all such wounds, because infection or salivary fistula is not an infrequent complication. If there is massive loss of tissue, as with a shotgun blast, it may be necessary to perform a cutaneous esophagostomy for feeding purposes and a cutaneous pharyngostomy for salivary drainage. A secondary reconstructive procedure is then required after the initial healing is complete. Most surgeons advocate primary repair of all esophageal injuries if accomplished early. Delays of greater than 12 hours significantly increase the risk of repair dehiscence, wound abscess, and death. Neck esophageal injuries diagnosed more than 24 to 48 hours after injury are best managed initially by diversion and drainage.

Thorax

One quarter of civilian trauma deaths are caused by thoracic trauma, and two thirds of these deaths occur after the patient reaches the hospital. Mortality rates of hospitalized patients with an isolated chest injury range from 4% to 8%; they increase to 10% to 50% when one other organ system is involved and rise to 35% when multiple additional organ systems are involved. Many of these deaths can be prevented with prompt diagnosis and correct management. Despite these high mortality rates, most thoracic injuries do not require a thoracotomy but rather simple lifesaving maneuvers of airway control and tube thoracostomy.

Mechanism of Injury

The life-threatening injuries incurred in penetrating trauma are distinctly different from those of blunt injuries. Penetrating thoracic injuries (e.g., stab wounds, gunshot wounds, and impalement on a foreign body) primarily injure the peripheral lung, producing both a hemothorax and pneumothorax. More than 80% of all penetrating chest wounds cause a hemothorax, and nearly all cause a pneumothorax. Penetrating injuries that enter or traverse the mediastinum must also be evaluated for potential cardiac, great vessel, or esophageal injury. Hemodynamically unstable patients with mediastinal entering or traversing wounds should be considered to have exsanguinating thoracic hemorrhage, pericardial tamponade, or tension pneumothorax. Preparation for immediate thoracotomy is indicated.

Blunt trauma can induce injury by three distinct mechanisms: a direct blow to the chest (e.g., rib fracture), deceleration injury (e.g., pulmonary or cardiac contusion and aortic tear), and compression injury (e.g., cardiac and diaphragm rupture). Rib fracture is the most common sign of blunt thoracic trauma. The less common fractures of the scapula, sternum, or first rib suggest massive force of injury and should invoke a thorough search for multisystem injury. In adults the bony thoracic cage absorbs much of the shock of blunt trauma. In children, the flexible cartilaginous thoracic structures allow the transmission of blunt force to the intrathoracic structures, resulting in a higher incidence of pulmonary contusion than of rib fractures.

CHEST WALL

Rib Fractures. Fracture of the ribs is the most common thoracic injury

With simple fractures, pain on inspiration is the principal symptom. Localized pain, tenderness, and occasionally crepitus confirm the diagnosis. A chest x-ray should be obtained to exclude other intrathoracic injuries and not necessarily to identify a rib fracture. The use of narcotics in small amounts, intercostal nerve blocks, and muscle relaxants are usually adequate treatment. Hospital admission for pain relief, cough assistance, and endotracheal suction may be necessary for several days, particularly in elderly patients. Underestimating the pathophysiologic effect of simple rib fracture, particularly in the elderly patient, is one of the primary pitfalls in trauma care. Rib belts and adhesive taping, although once popular, should be avoided because the resultant limitation in motion increases the incidence of retained secretions and atelectasis. Fracture of the upper ribs (1 through 3), clavicle, or scapula implies significant trauma, and associated major vascular injury must be suspected, although this exact association has been questioned. One report documents a 14% incidence of vascular injury in patients sustaining first rib fractures. All had associated absent pulse, brachial plexus injury, or a displaced fracture, implying that angiography may be selectively employed in this group of patients.

Flail Chest. Unilateral fracture of four or more ribs anteriorly and posteriorly or bilateral anterior or costochondral fracture of four or five ribs produces enough instability that paradoxical respiratory motion results in hypoventilation of an unacceptable degree . Although usually visually apparent in the unconscious patient, because of splinting, the flail segment may not be readily apparent in the conscious patient. If severe and untreated, atelectasis, hypercapnia, hypoxia, accumulations of secretions, and ineffective cough occur. The pathophysiologic effects may be present immediately or may progress over several hours and present as late respiratory decompensation. Excellent pain relief and improved ventilation can often be provided by a segmental epidural anesthetic or serial intercostal rib blocks. Intrapleural anesthetic administration (usually via a previously placed chest tube) rarely provides adequate pain relief.

If spontaneous respirations prove inadequate, endotracheal intubation with the use of a volume respirator has largely supplanted attempts at stabilization of the chest wall. A respiratory rate of more than 40 breaths per minute and a PO 2 of less than 60 mm. Hg on 60% FIO 2 are indications for intubation and mechanical ventilation. The presence of pre-existing chronic lung disease, depressed level of consciousness, and concomitant intra-abdominal injuries are also relative indications for intubation. Only rarely is sternal fracture displacement or rib overlap and displacement severe enough to warrant open reduction and internal fixation.