Trauma to the child's airway and thorax results in a variety of injuries that respond effectively to appropriate treatment. Early recognition results from a high index of suspicion, recognition of the unique features of the developing child, and an understanding of the patterns of injury associated with the pediatrie airway and thorax. Proper treatment of injury that compromises ventilation results in low mortality and morbidity.
Since management of the injured child within a pediatrie trauma center requires a multidiscipHnary approach, a predetermined sequence of action is essential to avoid oversight of life- threaten ing injury. Trauma to children occurs in recognizable patterns that allow the receiving team to anticipate specific injuries and prepare appropriate methods for intervention. Each regional center must establish a systematic protocol to care for young accident victims.
Diagnosis and treatment occur simultaneously. The most crucial aspect of pediatrie trauma resuscitation is effective management of injury which compromises ventilation; the two critical components in order of importance are the airway and thorax. l Without effective airway management the child will succumb to tissue anoxia, especially of the brain. Head trauma occurred in 48% of 760 children with blunt injury at Children's Hospital National Medical Center during an 18-month period (1985-86), while maxillofacial trauma occurred in 15% of this group of children. Since head injury occurs frequently in children and is the cause of death in a majority, prevention of secondary brain injury from increase in intracranial pressure requires early airway control.2'3 Recognition of the unique aspects of the small airway, development of appropriate manual skills and knowledge of possible technical misadventures will improve airway management and decrease mortality.
Contributing to the difficulty of pediatrie airway management are the small size of the airway and the need for customized instruments. The oral cavity is small with a large tongue that easily obstructs the airway. The larynx of the child is high and anterior in position, located at the level of the third cervical vertebra. The vocal cords are cartilaginous, distensible, and easily damaged. The trachea of the child is short - approximately one half the length of the adult. Because of these anatomic features, intubation of the esophagus and right main stem bronchus occur easily, with consequent hypoxia, respiratory arrest, or anoxic encephalopathy.
Life-threatening obstruction of the airway of an injured child may result from the presence of blood, vomitus, secretions, or a foreign object. The most frequent cause of airway obstruction in injured children is posterior displacement of the tongue, especially in a child with severe maxillofacial injury. Although unusual in children, penetrating or crushing trauma to the larynx or trachea occur with "clothes-line" injuries or when patients strike the dashboard of an automobile.4 Laryngeal edema and obstruction can also result from inhalation injury from bums.
The pediatrie patient with hypoxia due to respiratory insufficiency from trauma manifests agitation, dyspnea, or tachypnea. The diagnosis of airway obstruction is made by observing the mechanics of respiration. Upper airway obstruction is present in a child with stridor who exhibits cyanosis, chest wall retraction, and decreased breath sounds. Disruption of the trachea, bronchus, or esophagus is probable when initial examination demonstrates subcutaneous emphysema of the neck. Palpation of the trachea helps confirm this suspicion.
The goal of airway management for the trauma patient is optimum ventilation and oxygénation while protecting the cervical spine. ' One should presume that any injured child sustains an injury to the cervical spine. Immobilization of the head in a neutral position prevents manipulation of the cervical spine that may result in spinal cord injury with quadriplegia. A lateral x-ray film of the cervical spine from Cl to C7 is essential to rule out vertebral injury. Occasionally, congenital vertebral anomaly or pseudosubluxation of C2 to C3 can confuse evaluation. Successful airway management usually occurs with simple maneuvers. An open airway results by using the chin lift or jaw thrust maneuver; the mouth and oropharynx are cleared of secretions and debris by suction, while oxygen is administered by mask at 10 liters per minute.
If the child is unconscious or ventilation inefficient, mechanical methods of airway management are helpful. Insertion of an oral airway into the oropharynx is best accomplished by directly visualizing the oropharynx while elevating the tongue with a tongue blade. Vomiting may result if the gag reflex is intact. Orotracheal intubation is preferable for children when spontaneous respiration is absent. Nasotracheal intubation easily injures the nasal passage and is complicated by the presence of adenoid tissue. Also, the curve of the posterior pharynx complicates proper placement of the nasotracheal tube into the trachea, which lies anterior and cephalad and enhances the potential for esophageal intubation. Since the cricoid ring is the narrowest portion of the trachea, uncuffed tubes avoid subglottic trauma that may result in stenosis. A simple technique to estimate the size of the endotracheal tube for a child is to choose a tube with the approximate diameter of the patient's external nares or little finger. Optimal placement of the endotracheal tube tip is below the larynx and 1 to 2 cm above the carina. Ascertain proper position by listening to breath sounds over both lung apices, by observing the symmetry of thoracic excursions and by auscultation of the left upper quadrant for gastric air flow. The endotracheal tube is withdrawn until breath sounds are equal at both apices. If the tube is in the proper position but breath sounds are unequal, suspect a pneumothorax. A chest x-ray confirms the proper tube placement once life-threatening injury is treated. Secure the endotracheal tube to avoid dislodgement into the esophagus, an unfortunate common occurrence.
Complete upper airway obstruction in children is most commonly the result of a foreign body or maxillofacial injury. Acute management of foreign body obstruction is by laryngoscopy and removal with forceps. Very rarely, the child requires needle cricothyroidotomy (14 to 16 gauge) to provide a rapid, temporary airway until a definitive procedure can be performed in a controlled environment. Endotracheal intubation is possible in almost all children; nevertheless, a child may require surgical access to the airway. Cricothyroidotomy through a midline skin incision is preferable to tracheostomy because of the more superficial location and rapid access to the cricoid membrane. Emergency tracheostomy in children may cause significant bleeding from the thyroid, and bilateral pneumothorax may result if dissection of the trachea is imprecise. Tracheobronchial disruption may require trachea! intubation and emergency thoracostomy to establish an airway.
Once the airway is secure, the mechanics of breathing depend upon the integrity of the thorax which is the second critical component of ventilation. Thoracic injury occurs frequently enough in children to require evaluation during initial resuscitation. Up to 30% of the children who sustain trauma have chest injuries5"8; the mortality ranges from 7% to 14% in older children7"9 and 25% in children less than 5 years of age.9 The addition of two major extrathoracic injuries raises the mortality to 58%.9 Thoracic trauma in children usually results from blunt force associated with rapid deceleration in a motor vehicle or pedestrian accident, fenetration of the thorax is less common although injury caused by objects such as plate glass, stones, guns and knives does occur.9,10
Successful treatment of life-threatening chest injury depends on early recognition. Since the blood volume of a small patient is a large component of his or her body weight (8% vs. 6% in adults) a relatively small blood loss can lead to hypovolemia and shock. It is therefore important to identify occult sequestration of blood in the thorax during initial resuscitation. Other characteristics of the child are the increased compliance of the bony thorax and the free movement of the mediastinum. Compression of the chest results in a low incidence of rib fracture as a consequence of the elasticity of the bony and cartilaginous structures. The mediastinum in a child is capable of wide shifts with dislocation of the heart, compression of the lung, and angulation of the great vessels and of the trachea. Following injury aerophagia produces gastric dilatation which may compromise diaphragmatic excursion and put the child at risk for aspiration. Similarly, perforation of the upper gastrointestinal tract can lead to massive pneumoperitoneum which also causes restricted movement and impingement of the diaphragm resulting in respiratory insufficiency.
Because of the low incidence of penetrating trauma in the child, injury to the trachea and main bronchi is rare.7-9 However, the child is vulnerable to trachea! and bronchial tears after crushing injury from heavy objects often pulled over onto the chest. Disruption of the tracheobronchial tree is suspected when there is persistent massive air leak through a thoracostomy tube following treatment for pneumothorax. The presence of mediastinal and subcutaneous emphysema, hemoptysis, tension pneumothorax or massive atelectasis must also raise the question of major airway injury.11,13
If the clinical condition permits, bronchoscopy may demonstrate a laceration of the tracheobronchial tree.12 However, if the injury is readily apparent from clinical signs, immediate thoracotomy may be necessary. Direct repair of a trachea! injury and establishment of a tracheostomy is adequate for high trachea! lesions. A low trachea! or bronchial injury is best approached through a median stemotomy. Extensive laceration of the bronchial tree can require resection of the involved lobe of the lung. Late stenosis of the subglottic trachea usually occurs after forceful intubation of the airway during emergency resuscitation.
Although fracture of the ribs and sternum are uncommon in the child due to the elasticity of the cartilaginous and bony skeleton, deceleration injury involving transfer of large kinetic energy can result in fracture of the ribs.10-11 These are best treated by analgesia and pulmonary toilet to prevent atelectasis. Rarely, multiple rib fractures in sequence produce a flail chest with paradoxical movement of the chest wall with respiratory embarrassment and hypotension. Treatment requires endotracheal intubation and ventilator support.10,14-16
Blunt trauma to the thorax can cause pulmonary contusion with parenchymal hemorrhage and edema resulting in hypoxia from disruption of the effectiveness of the alveolar-capillary interface.17'19 The child with significant pulmonary contusion has low arterial PO2 and an increase in intrapulmonary shunt to the point where hypoxemia progresses and respiratory failure follows. A Swan-Ganz catheter is very useful in monitoring the pulmonary capillary wedge pressure to avoid fluid overload and compromise of the injured lung. Endotracheal intubation and mechanical ventilation with positive end-expiratory pressure is employed. Neuromuscular blockade is effective in maximizing the benefit of the ventilator which may be required for long periods. For severe pulmonary contusions maximum fluid resuscitation to produce a serum osmolarity between 290 and 300 tnOsm may be necessary. Antibiotic administration is useful to minimize the chance of infection of the compromised parenchyma.
Pneumothorax is the most common consequence of thoracic injury in the child. l° Collapse of the ipsilateral lung and increase in intrathoracic pressure occur when air escapes into the pleural space secondary to disruption of lung parenchyma, to a tear in the tracheobronchial tree, to esophageal perforation or to penetration of the chest wall. Pneumothorax is usually present without rib fractures.
The child with a pneumothorax may be asymptomatic or in severe respiratory distress. Although pneumothorax is initially better tolerated than in the adult, rapid recognition is essential. Abrasions of the chest wall, subcutaneous emphysema or hyperresonance to percussion suggest the diagnosis. Associated physical findings are decreased breath sounds on the ipsilateral side and a shift of the trachea to the contralateral side. For the asymptomatic child with a pneumothorax of less than 15%, observation without thoracostomy is appropriate since the air will spontaneously resorfa. Symptomatic pneumothorax requires treatment by needle aspiration of the pleural space and insertion of a thoracostomy tube. Open wounds of the chest wall are treated by closure of the wound and placement of a thoracostomy tube. Any child with a chest injury who requires general anesthesia needs a thoracostomy tube to prevent intraoperative tension pneumothorax.
Tension pneumothorax develops as a consequence of progressive entry of air into the pleural space with elevation of the intrapleural pressure causing collapse of the ipsilateral lung, shift of the mediastinum to cause compression of the contralateral lung and depression of the ipsilateral diaphragm (Figure). Excessive shift of the mediastinal structures results in angulation of the vena cava with decrease in blood return to the right side of the heart, decrease in cardiac output and potentially lethal cardiovascular collapse. Treatment by rapid needle aspiration and insertion of a thoracostomy tube is essential.
Trauma to the major thoracic vessels in children is unusual because of the low incidence of penetrating injury. Nevertheless, blood can accumulate in the intrapleural space of the child from injury to an intercostal artery. Large amounts of blood can be lost into the chest cavity resulting in significant hypotension. Important in the treatment of hemothorax is establishment of a functioning intravenous access route before placement of a tube thoracostomy. Rapid evacuation of blood from the pleura! space can aggravate hypovolemia and lead to cardiac arrest. Proper placement of a tube thoracostomy in the posterior axillary line or the midaxillary line will re-expand the lung and allow monitoring of ongoing blood loss. Bleeding from the thoracostomy tube at a rate of 1 to 2 cc/kg/hr requires thoracotomy to establish hemostasis. Autotransfusion of aspirated blood is appropriate if a reinfiision system is available.20 Inadequate evacuation of intrathoracic blood may result in fibrothorax with lung entrapment.
Pericardial tamponade occurs from accumulation of blood within the pericardial cavity following injury to the myocardium. Similarly, air which dissects into the pericardium from a bronchial injury following mechanical ventilation with high inflating pressure and positive end -expiratory pressure may produce tamponade. Decrease in venous return and restriction of cardiac output occurs with relatively small volumes of fluid or air within the pericardium because of the inelasticity of the pericardial membrane. The diagnosis of cardiac tamponade is difficult in the small child. Hypotension in spite of fluid resuscitation after injury, neck vein distension, elevated central venous pressure, and peripheral vasoconstriction suggest the diagnosis21; it is difficult to demonstrate a paradoxical pulse in the child. Chest x-ray is usually not helpful but sonography can accurately demonstrate fluid within the pericardium and estimate the volume. If this technique is not available, diagnostic pericardiocentesis is performed. Aspiration of blood or air results in immediate cardiovascular improvement.
Traumatic asphyxia results from direct compression of the chest wall or upper abdomen. This can occur when a child is trampled by a crowd or run over by a vehicle.22,23 Anticipation of the injury results in closure of the glottis, tensing of the thoracoabdominal muscles and deep inspiration.24 The pressure exerted on the chest is transmitted through the inferior and superior vena cavae since valves are absent. The fece and neck become cyanotic with petechiae of the head, neck, and chest. Periorbital edema and subconjunctival and retinal hemorrhage are often present. The patient is disoriented, tachypnic, and may have hemoptysis, or respiratory insufficiency. The diagnosis is usually evident from the disparity in the appearance of the head and neck and the lower body. Occasionally, a pneumothorax occurs (Figure). Cardiac contusion and hepatic injury are associated with this phenomenon. The asphyxia itself is usually self-limiting and resolves over a period of several weeks, but associated injuries must be carefully sought and treated.
Figure. A 5-year-old female was ejected from the rear of an automobile, and pinned under the right, front wheel of a second automobile in the region of the epigastrium. The child manifests traumatic asphyxia.
The child who is exposed to a closed-space flame burn may have direct injury to the tracheobronchial tree. Inhalation of smoke causes a chemical tracheobronchitis when products of incomplete combustion make contact with the respiratory tract. Mucosal edema and destruction of cilia can cause airway obstruction which is also aggravated by sloughed mucosal debris. 25 Suggestive clinical signs are singed nasal mucosa, hoarseness, cyanosis, cough, wheezing, tachypnea or productive sputum. Progressive pulmonary edema and bronchopneumonia may follow. Chest x-ray may initially appear normal even though severe injury is present. Serum carbon monoxide levels and blood gas values are useful measurements to identify children who need ventilatory support.
Therapy for bum inhalation injury includes humidification of inspired air, postural drainage, vigorous pulmonary toilet, intratracheai suction, bronchoscopy, and the use of bronchodilators. To avoid excessive fluid hydration a Swan-Ganz catheter is placed for physiologic monitoring. Endotracheal intubation allows vigorous pulmonary toilet to remove alveolar debris. Positive end-expiratory pressure is used in management of the injured lung along with appropriate antibiotics based on serial trachea! and blood cultures.
Direct injury to the esophagus from blunt or penetrating objects is rare. 10 The most common cause of esophageal perforation in children is internal instrumentation. The three usual points of injury are the pharyngoesophageal junction, the aortic arch, or the diaphragmatic hiatus; areas of normal narrowing of the esophagus. Iatrogenic perforation of the upper esophagus at the thoracic inlet may follow rough insertion of a nasogastric tube, especially in infants. Perforation of the esophagus from retching is less common in children, but distal esophageal injury does occur with major chest compression. Ingestion of caustic substances such as lye can cause an esophageal burn which leads to perforation and stricture. Finally, a child may bite into an inner tube rupturing the esophagus at the diaphragmatic hiatus because of the sudden, rapid pneumatic pressure rise.26,27
The diagnosis of esophageal perforation requires a high index of suspicion. Clinical signs that suggest perforation are mediastinal or subcutaneous emphysema, cardiovascular collapse, pneumothorax, pleural fluid, or a mediastinal crunch on auscultation. The presence of an esophageal injury is best confirmed by contrast radiography during fluoroscopy and esophagoscopy. Early recognition is crucial since mediastinitis, empyema, and sepsis occur with minimal delays.
Management of the injury depends on its anatomic location. An injury to the cervical esophagus is properly treated by primary repair, adequate drainage, and intravenous antibiotics. Occasionally an injury such as perforation from a nasogastric tube in an infant can be treated by expectant therapy consisting of antibiotics alone. Perforation of the intrathoracic esophagus requires treatment by prompt thoracotomy with closure of the esophageal perforation, thoracostomy drainage, and antibiotics. Repairs of large lacerations of the esophagus are difficult and may require reinforcement by an onlay gastric patch,28 pericardium,29 or omental flap. 30 If the injury is extensive or unrecognized for a period, use of a proximal esophagostomy diverts saliva and decreases contamination. A well placed thoracostomy tube is essential to drain the chest. Interposition esophageal substitutes are not indicated for acute perforation but cervical esophagostomy and abandonment of the esophagus may be necessary for irreparable injuries.31,32
Initial treatment after caustic ingestion10 consists of prompt esophagoscopy to the proximal level of the burn. If the bum is significant the child is treated for 3 weeks on an intravenous antibiotic and steroid. An upper gastrointestinal contrast study is performed to document the extent of the injury and the presence of stricture. Occasionally, a child is unable to maintain adequate caloric intake by mouth and requires either a gastrostomy or intravenous parenteral alimentation. Placement of a gastrostomy allows passage of a silk string for retrograde dilatation which may be required frequently until swallowing is adequate. Occasionally, injection of local steroid into a resistant cicatrix helps soften the scar and improve patency.33 Segmental resection of the esophagus with end-to-end anastomosis is indicated if the segment is short and the stricture is not responsive to dilatation. Long segment stricture that is unresponsive to repeated dilatation suggests the need for total esophageal replacement with a colon interposition or gastric tube.31,32 Since esophageal carcinoma can develop in injured esophageal tissue, resection of the esophagus is desirable.34
Forceful blunt trauma to the lower chest or upper abdomen can result in tearing of the diaphragm commonly on the left side.35 Abdominal contents enter die thoracic cavity with incarceration or respiratory embarrassment. Distortion of die diaphragmatic contour or abnormal position of the nasogastric tube on an upright chest film is suggestive. Unrecognized diaphragmatic injury can result in the late onset of respiratory compromise or incarceration of abdominal viscera requiring emergency treatment. Rarely, unrecognized injury permits thoracic displacement of the spleen which can be injured during insertion of a thoracostomy tube. Surgical repair is best accomplished by laparotomy to deal with any concomitant injury to abdominal viscera.
Children continue to sustain life -threatening injury that can be treated successfully. Management of the airway and breathing are the crucial steps which assure adequate ventilation of the child. If properly prepared, those individuals responsible for the emergency treatment of children should be able to save a high percentage of children who suffer injuries to the airway and thorax.
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36 Eichdberger MR, Randolph JG: Abdominal trauma, in Welch KS. Randolph JG. Ravitch MM, et al: Prdiatric Surgery Chicago. Year Book Medical Publishers. 1986. p 162.