THE TRAUMATIZED CHILD

0889-8537/96 $0.00

TRAUMA

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THE TRAUMATIZED CHILD J. Michael Badgw-ell, MD

Trauma is the number one cause of death in children between the ages of 1 and 14 years. Because the appropriate management of traumatized children by all health care providers significantly affects morbidity and survival, it is important to review the care of these children at all stages after the traumatic incident, beginning with a discussion of the initial resuscitative care of the traumatized child. INITIAL RESUSCITATION AND CARE

Hypothermia Although extreme hypothermia (e.g., such as that which would occur in a child who falls in an ice-covered lake) may actually preserve central nervous system and myocardial function, hypothermia that is less than extreme is detrimental to the traumatized child. By depressing hemodynamic function and prolonging acidosis, hypothermia decreases one's ability to perform adequate cardiopulmonary resuscitation. Furthermore, hypothermia increases oxygen consumption while decreasing oxygen delivery (release) to tissues. Perhaps more important is the fact that hypothermia impairs platelet function and may lead to prolonged bleeding. In addition, the postoperative consequences (rewarming, hypotension, shivering, and discomfort) can significantly contribute to perioperative morbidity. Therefore, in children, it is essential to take action early in the course of management to promote the preservation of body heat. Hypothermia assumes even greater importance in the traumatized

From the Departments of Anesthesiology and Pediatrics, Texas Tech University Health Sciences Center, Lubbock, Texas ~

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ANESTHESIOLOGY CLINICS OF NORTH AMERICA

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VOLUME 14 NUMBER 1 MARCH 1996

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pediatric patient because of the child's larger surface-to-body weight ratio and higher metabolic rate.

Prevention of Hypothermia

No single method or device used alone will reliably prevent inadvertent hypothermia. Results are best when several methods are combined. If possible, patients kept in a holding area should be kept well covered with warmed blankets. The ambient operating room temperature should be elevated before the patient enters. The ambient temperature should ideally be as high as 22°C to 24°C for the incoming trauma patient. By keeping the skin warm, rapid heat transfer from the core to the periphery is reduced when vasodilatation occurs after anesthetic induction. In these high-risk patients, all exposed areas should be covered, including the head (an important source of heat loss in infants). Skin preparations and irrigation fluid should be warmed and warm saline pads placed on exposed surfaces. All fluids should be warmed in traumatized children where large fluid shifts and rapid replacement are anticipated. Conventional treatment of these patients includes the infusion of warmed (37"C42"C) intravenous (IV) fluids for core rewarming. It is generally accepted that core rewarming is more efficient than shell rewarming. It was recently determined that the infusion of very hot IV fluids (65°C) via a specially designed multiport balloon-tipped catheter inserted into the vena cavae was safe and effective in the treatment of hypothermia in animals.I3 Simple conductive warmers can increase blood temperature at about 32°C at 100 mL/min but rapid infusion devices are now available that can fully warm blood to 37°C at flow rates as high as 750 mL/min per each 8 French intravenous catheter. (Note: Always monitor central venous pressure [CVP] if using high flow rates in children.) Cold blood is viscous, difficult to infuse, and it worsens peripheral vasoconstriction. Furthermore, rapid infusion of cold blood via a central line may cause arrhythmias. At 4"C, the oxygen hemoglobin association curve is so leftshifted that even at venous oxygen tension, hemoglobin is still 100% saturated. Cold blood is completely unable to give any oxygen to the tissues and acts only as an inert volume expander. Heaters/humidifiers are electronically heated devices that provide full artificial heating and humidification. Advantages of warming and humidification of inspired gases include conservation of evaporative heat from the trachea and prevention of drying, mucosal crusting, and ciliary paraly~is.~ Condensation ("rainout"), contamination, water overload (in neonates), and thermal burns can occur. To avoid these problems, a simple heat and moisture exchange (HME) may be placed in the airway to provide adequate heat and moisture in both children3 and adults. HMEs consist of a high-surface-area hygroscopic membrane filter placed in the airway that traps warmth and humidity of the

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patient's expired air. An HME cannot add heat to an already hypothermic patient. A conductive mattress containing water heated to 40°C to 41°C is often placed under the patient but is not very efficient.19It comes into contact with only one-third of the body surface area, the patient's body weight compresses the adjacent capillaries (which negates its beneficial effect), cotton sheets insulate its conduction, and the device takes 20 minutes to warm up. Local burns have been reported." A more effective approach is to use a forced-air convective exchange blanket, which consists of an extremely light air mattress through which heated air is forced by a compressor (Fig. 1).Initially introduced to provide rewarming during the recovery period, various modifications allow the application of the blanket to pediatric patients. By providing both insulation and active cutaneous warming, the forced-air exchange blanket appears to be a very effective method of preventing intraoperative hypothermia even when used alone.30Whereas redistribution hypothermia is difficult to treat,'* it can be prevented by cutaneous warming before induction of anesthesia.22Therefore, it appears to be logical to apply the aggressive use of warming with convective air prior to surgery in the traumatized child. Airway and Breathing

Swelling, secretions, and bleeding from trauma, and the collapse of soft tissue as the child loses consciousness, may cause obstruction of the

Figure 1. Convective air heating systems provide forced warm air that may be used to restore or maintain temperature in pediatric patients during surgery. (A 2-year-old child is shown lying on a Warm-Touch convective air warming blanket, Mallinckrodt Medical, St. Louis, MO.)

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airway. If obstruction is present, the airway should be opened by headSpontaneously tilt/chin-lift or, with neck injury, with gentle breathing children should receive supplemental oxygen, either by face mask or by nasal cannulae. If respiratory compromise persists, positivepressure ventilation, using bag and mask and endotracheal intubation, may be required. In a child with suspected neck injury, endotracheal intubation may be particularly troublesome; this is discussed later in this article. Adequacy of ventilation and patency of the airway is confirmed by the absence of subcostal and intercostal retractions, equal breath sounds, coordinated chest and abdominal rise, pulse oximetry readings, and arterial blood gas determinations. Gastric dilation that occurs as a result of crying or positive-pressure ventilation may compromise ventilation. If this occurs, the stomach should be decompressed using a suction catheter. A portable anesthesia breathing circuit is preferred to a selfinflating resuscitation bag, because the former allows spontaneous respiration, but the latter requires positive-pressure ventilation that may cause gastric dilation. Traumatized children are usually better off if they are allowed to breath spontaneously, if they are able to do so. If the child can maintain an airway, he or she should be allowed to do so, with added support as necessary. Generally speaking, if a traumatized child will tolerate a plastic artificial oral airway, he or she is obtunded enough to require an endotracheal tube. This is also true for nasal airways, but an artificial nasal airway may produce epistaxis or nasopharyngeal bleeding (especially in the hypothermic and, possibly, coagulopathic child). Therefore, artificial airways have limited usefulness in the trauma situation. Circulation and Vascular Access Usually, the most significant pathophysiologic defect in traumatized children is hemorrhagic shock. The earliest manifestations of shock are delayed capillary refill, mottled skin, and cool extremities. Tachycardia also occurs early in shock and indicates a loss of circulating blood volume. In the nonanesthetized patient, systolic blood pressure remains relatively constant because of peripheral vasoconstriction and may be maintained until there is a 30% to 40% loss of circulating blood volume. Diastolic blood pressure also may be maintained due to vasoconstriction and, therefore, the hypovolemic patient may have a narrowed pulse pressure. By contrast, in the anesthetized child, diastolic blood pressure is a good indicator of filling pressure and decreases in the hypovolemic child, often precipitously after the induction of anesthesia. Peripheral pulses may be absent, depending on the intensity of vasoconstriction. Absent or narrowed peripheral pulses and tachycardia should alert the clinician that cardiovascular collapse is imminent. Arterial pH is a good indicator of circulatory status. If pH is low, in the presence of normal or low carbon dioxide, it should be assumed that circulating blood volume

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is inadequate, until proven otherwise. Metabolic acidosis, secondary to low perfusion state, in hypovolemic children is corrected with adequate fluid resuscitation. Should the pH fall below 7.2 in a child with adequate ventilation, sodium bicarbonate may be added to fluid replacement (dose = body weight in kg X 0.15 mEq X base deficit, given as an IV bolus, followed by reassessment of the pH).' Initial treatment of hemorrhagic shock is intravascular resuscitation with crystalloid solutions. Therefore, establishing vascular access with large-bore cannulae has top priority. Percutaneous cannulation of internal jugular or subclavian veins is hazardous during initial resuscitation because of the risk of pneumothorax or hemothorax.12If the clinician is proficient with cannulation of these large central veins, this procedure is recommended in life-threatening situations in which no other access is available. Furthermore, if abdominal or thoracic bleeding is suspected, at least one IV site should be in the neck or upper extremity. In addition, a central venous pressure catheter is essential if use of a rapid mechanical infusion system is planned. Internal jugular or subclavian veins may be cannulated using techniques needing only slight modifications from those used in adults.' Initially, venous access should be established via a percutaneous route, if possible. If this route is unsuccessful, a direct cut down at the saphenous (Fig. Z), cephalic, or external jugular vein may be performed. Alternatively, a femoral vein may be cannulated using the Seldinger technique (Fig. 3). There are several different kits that are available for

Figure 2. Anatomic relationships and technique for saphenous cutdown. (From American Heart Association: Textbook of Pediatric Advanced Life Support. Dallas, AHA, 1994; with permission, copyright American Heart Association.)

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Figure 3. Anatomic relationships and technique for femoral vein needle insertion as first step in the Seldinger technique. (From American Heart Association: Textbook of Pediatric Advanced Life Support. Dallas, AHA, 1994; with permission, copyright American Heart Association.)

femoral vein cannulation or can be assembled from readily available material for use in the Seldinger technique. First, depending on the child’s size, either a #20 or a #22 catheter (Deseret Angiocath, BectonDickinson Vascular Access, Sandy, UT) is inserted into the vein. In a smaller child, the use of a 0.45-mm spring wire guide (#AW-04018, Arrow Duoflex, Reading, PA) may facilitate insertion of a #22 (or larger) catheter. In a larger child, the insertion of a #20 catheter will allow a 0.635-mm spring guide wire and then the insertion of a 7-French catheter (Rapid Infusion Catheter Exchange Set, #RC-09700, Arrow Duoflex). A 7-French catheter will allow infusion rates of up to 750 mL/min using a mechanical rapid infusion system. Fluids may also be administered through an intraosseous needle.14 In this technique, a bone-marrow needle (#15 Jamshidi, Baxter Healthcare Corporation, Valencia, CA) or #14-#18 Cook intraosseous infusion needle (Cook Critical Care, Bloomington, IN) is percutaneously inserted into the flat portion of the proximal tibia just below, and medial to, the tibia1 tuberosity (Fig. 4). The depth of needle insertion should be planned before placement. If it is advanced too far, the needle will penetrate the posterior cortex and will not allow infusion. Aspiration of bone marrow identifies adequate needle position. Crystalloids, blood products, and drugs may be given. Fluids may be infused, by the intraosseus route, at rates up to 40 mL/min (using 300 mm Hg pressure).

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< 90" to Medial

Figure 4. Anatomic relationships and technique for intraosseous cannulation. (From American Heart Association: Textbook of Pediatric Advanced Life Support. Dallas, AHA, 1994; with permission, copyright American Heart Association.)

For initial fluid resuscitation, Ringer's lactate (RL) is administered as a bolus (20 mL/kg). If vital signs fail to improve, boluses of RL may be repeated three times. If, despite the infusion of RL, hypotension or shock continues, either 0 - or type-specific red blood cells are administered (10 mL/kg increments). The child with significant hemorrhage, who has required large volumes of fluid (3040 mL/kg) to restore a stable hemodynamic status, will probably require transfusion of red blood cells, when these become available. PREOPERATIVE MANAGEMENT AND INDUCTION OF ANESTHESIA

Body Heat Preservation When preparing the operating room, everything possible should be done to aid in preserving the body temperature of the traumatized child (see section on prevention of hypothermia). Traditional warming techniques (i.e., warming the room, warming intravenous fluids, and warming and humidifying inspired gases) are limited in their efficacy but should be used as part of a comprehensive warming plan that includes the newer convective air warming. Premedication

In general, children with multiple-system trauma or head injury should not receive sedative premedication. In the awake, responsive

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child who has a stable circulatory status, the IV administration of morphine sulfate (0.05-0.1 mg/kg) or fentanyl ( 2 4 kg/kg) will provide satisfactory analgesia. Agitation in a traumatized child may be caused by hypoxia or increased intracranial pressure (ICP). These conditions should be ruled out, or treated, before sedative medications are given. Atropine (0.02 mg/kg) may be given IV at the time of induction to prevent the bradycardia associated with laryngoscopy and with the administration of succinylcholine or fentanyl.

Monitors Along with the usual monitors, an arterial catheter is essential. A CVP catheter is not essential in the initial phase of resuscitation and may be inserted after the patient has been stabilized (see later discussion of CVP requirements during mechanical rapid blood infusion). Volume status may be monitored using diastolic blood pressure, capillary refill time, urine output, and end-tidal CO,. A gradually decreasing end-tidal CO, value (when ventilation is constant) indicates decreasing pulmonary perfusion?

Induction of Anesthesia Hypovolemia and a full stomach put traumatized children at risk for hypotension and pulmonary aspiration during induction of anesthesia. Therefore, a "rapid-sequence" induction with an intravenous agent, preoxygenation, and cricoid pressure is indicated in most cases. In the child in whom neck injury is suspected, struggling may have dire ccwequences; in these cases, preoxygenation may be avoided if it causes the Aild to struggle more vigorously. Cricoid pressure should be avoided in cases of known or suspected fractured larynx (child in respiratory distress with history of neck trauma, with absence of cry or phonation, anterior neck soft-tissue swelling, and subcutaneous crepitus).

Intravenous Agents The requirements for IV anesthetics are decreased after trauma and hemorrhage because (1) the volume of distribution is decreased; (2) dilution of serum proteins (especially after crystalloid resuscitation) occurs, and, thus, less drug is bound and more free, active drug is available; and (3) blood flow to the brain and heart is well maintained despite poor perfusion to other organs. The IV anesthetic agent that is chosen should cause minimal depression of the heart and dilation of the peripheral vasculature. It is well known that ketamine supports blood pressure when the sympathetic nervous system is intact. There are data

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that indicate that ketamine causes myocardial depression and hypotension in animals with severe h y p ~ v o l e m i aTherefore, .~~ as an induction agent in traumatized children, ketamine should be given slowly (1-2 mg/kg) to those with moderate hypovolemia and probably not at all to those with severe hypovolemia. Ketamine increases ICP and is contraindicated in children with head trauma. Initially, in severely hypovolemic and obtunded children who require immediate surgery, 0, and a muscle relaxant may be all that are required. In less severe cases in whom moderate hypovolemia is present, fentanyl (0.5-2 Fg/kg), followed by a rapidly acting muscle relaxant, provides stable hemodynamics during anesthetic induction. The possibility of awareness exists with these regimens but may be a small price to pay for keeping a child alive. Judicious monitoring and the use of adjuvant drugs, as needed based on clinical signs, will minimize the risk of awareness. In children who receive no anesthetic agent or only fentanyl for induction, or in cases in which only fentanyl is used as the sole maintenance anesthetic agent, midazolam (0.05-0.2 mg/kg) may be given, after hemodynamic stability is achieved, to provide amnesia. Because it decreases cerebral oxygen consumption, ICP, and cerebral blood flow, thiopental is the drug of choice in children with head injury and stable volume status. To minimize myocardial depression and venodilalation in these children, thiopental should be given slowly. The hemodynamic effects of midazolam are similar to the effects of thiopental in hypovolemic children, and midazolam is less reliable in inducing anesthesia. Propofol is similar to thiopental as a myocardial depressant and may cause hypotension. Etomidate has limited usefulness in traumatized children because it may cause myoclonus and adrenal suppression. Muscle Relaxants

In the trauma situation, the ideal muscle relaxant should have a rapid onset of paralysis and minimal hemodynamic effect; also, it should not increase ICP or intraocular pressure. Although succinylcholine is not an ideal drug, the administration of 2 mg/kg is a rapid and effective aid in gaining control of the airway. The effects of this drug dissipate quickly, allowing revision of the airway management plan, if necessary. Hyperkalemia, secondary to the administration of succinylcholine, is not of concern in the early burn and trauma situation. Although succinylcholine causes a transient increase in the ICP, this effect has not been shown to affect adversely outcome in head-injured patients. The advantages of promptly gaining control of the airway (i.e., the favorable effect on ICP of improved oxygenation and ventilation) outweigh the possibility of the minor effect of a transient increase in ICP secondary to succinylcholine. Vecuronium is another useful muscle relaxant in the trauma situation. The administration of vecuronium (0.25 mg/ kg) provides intubating conditions in 1 to 1.5 minutes and is not associated with significant

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hemodynamic side effects or increased ICP. Priming techniques should be avoided, because even a small dose of vecuronium may produce apnea or airway obstruction in the hypovolemic child. Atracurium and mivacurium have histamine-releasing properties that may cause hypotension. The tachycardia that may result from the vagolytic effects of pancuronium is undesirable in situations of acute trauma, in which the heart rate is being used as an indicator of cardiovascular status. Pancuronium, however, may be a useful drug when bradycardia is anticipated as a result of the vagotonic effect of fentanyl. MAINTENANCE OF ANESTHESIA Anesthetic Agents

Children who are marginally or questionably volume replete are probably best managed with an opioid / 0 2 /muscle relaxant technique. Morphine, because of its vagal stimulation, histamine release, and alphaadrenergic blocking effect, is not a good drug for these children. Likewise, meperidine should be avoided, because of its histamine-releasing properties. Fentanyl provides good analgesia and provides hemodynamic stability in children with tenuous cardiovascular status. Because there is some venodilatation with fentanyl, the initial doses should be small (2-10 p,g/kg). If the child tolerates a small dose, incremental doses (up to 25-50 pg/kg) may be given. Sufentanil and alfentanil do not appear to have any significant pharmacodynamic advantage over fentanyl. Likewise, propofol has limited usefulness in hypovolemic pediatric patients, because it may depress cardiac output, in a dose-dependent fashion, in normovolemic children.23These adverse hemodynamic effects are likely to be exaggerated in the hypovolemic child; however, isoflurane, in appropriate inspired concentrations, is a useful drug in traumatized pediatric patients, after stable cardiovascular and hemodynamic status are achieved. Isoflurane may be useful to promote vasodilatation in the child who has been volume restored, but who is still vasoconstricted. Nitrous oxide is a myocardial depressant, reduces the concentration of oxygen that can be delivered, and may fill air-containing spaces that may be present in traumatized patients (e.g., pneumothorax and bowel obstruction). Therefore, it is rarely useful in the trauma setting. Fluid and Blood Products

Crystalloid. The goal of fluid management during maintenance of anesthesia for surgical repair of trauma is to replenish vascular and interstitial fluid volumes. As in adults, trauma and hypovolemic shock in children are associated with a decrease in functional extracellular fluid volume and an increase in intracellular volume33(Fig. 5). Therefore, additional resuscitative fluid should mimic that of extracellular fluid

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Normal Cell Fluid

hterstifial Fluid

Vascular Tree Arteriole

c-

c--

bed

Hemorrhagic Shock

Figure 5. Interstitial fluid is translocated, intravascularly and intracellularly, after hemorrhagic shock. This translocation of fluid results in a decrease in functional extracellular fluid and an increase in intracellular volume. (From Schwartz S, et al: Principles of Surgery, ed 5. New York, McGraw-Hill, 1989; with permission.)

(sodium concentration = 140-150 mEq/L).31Effective resuscitation (i.e., that which is associated with survival) requires the administration of red cells and crystalloid in excess of the amount of blood that is Therefore, effective resuscitation after massive hemorrhage causes edema, swelling, and obligatory weight gain (Fig. 6). It is not the goal of resuscitation to prevent this edema. It should be emphasized that the administration of hypotonic solutions (e.g., D5W or D50.2NS) causes intracellular edema without the beneficial effects of intravascular and interstitial repletion. Children, like adults, need balanced salt solutions to replace traumatic and surgical losses. It is recommended that dextrose-containing solutions be avoided in the trauma situation unless, based on the patient’s history, hypoglycemia is documented or strongly suspected. The hormonal stress response to trauma produces hyperglycemia in children. The administration of dextrose-containing solutions may cause further hyperglycemia, which has the potential to worsen cellular injury in partially ischemic brain tissue (through the mechanism of increased lactic acid production). Therefore, dextrose-containing solutions should not be used as a routine fluid for use in the volume restoration of hypovolemic children. Blood Component Therapy. Although measurements of ongoing

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Normal (P.D. - 90 mV)

ECW

0 ICW @ Cell Membrane

Hemorrhagic Shock (P.D. - 60 mV)

Neutral Na+- K+Exchange Pump Electrogenic Na+Pump

( 1Relative Na' Permeability

Figure 6. The failure of cellular pump mechanisms during hemorrhagic shock causes an increase in intracellular sodium and water and a decrease in extracellular water. lntracellular water excess causes the patient to swell. (From Schwartz S, et al: Principles of Surgery, ed 5. New York, McGraw-Hill, 1989; with permission.)

blood loss during surgery in the traumatized child may be attempted, these measurements are usually unreliable and may unnecessarily consume the time of ancillary personnel, who could be doing other, more important, things for the critically ill child. Rather, one can rely on clinical signs, such as capillary refill, temperature gradient (e.g., between rectum and skin), urine output, CVP, or diastolic blood pressure, as a guide for estimating blood loss and volume status. Remember that the hematocrit is merely a reflection of the ratio of red blood cells (RBC) to everything else that has been given ( e g , crystalloid and colloid); therefore, it is not a reflection per se of volume status. The hematocrit is, however, a useful guide for further therapy (i.e., more RBCs versus more fluid). RBCs. RBCs should be transfused to increase oxygen-carrying capacity in children who have lost a significant portion of their red cell mass. The decision to give RBCs is less difficult in the traumatized child than in the child undergoing elective surgery. Either 0 - ,cross-matched, or type-specific blood may be used to replace blood that has been previously, or continues to be, lost by the hypovolemic child. Whether to give cross-matched versus type-specific blood depends on the urgency of the situation. In the equation DO, = CO X CaO, = oxygen delivery (CO = cardiac output, and CaO, = oxygen content), hemoglobin is the major oxygen "container," and is, therefore, a major determinant of DO,. Anemic children compensate for low hemoglobin by increasing heart rate to increased cardiac output. Although healthy children or those with chronic anemia may tolerate hemoglobin values of 7 g/dL or

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less, the child with multisystem trauma, who may have coexisting anemia, hypovolemia, acidemia, and hypothermia, requires transfusion to a hematocrit of 33% to 35%. Although it is necessary to filter (using a 170-pm pore filter), measure, and warm administered blood cells, it is not necessary to filter cells with a very small pore filter (e.g., a 2040-km filter).**Warm blood may be administered very rapidly to children using a mechanical rapidinfusion system. Although a 7-French catheter will allow blood administration at 750 mL/min, this very rapid flow rate may overload the right heart and rapidly cause pulmonary edema. Because there are no maximum flow formulae that can take into account all of the patient's variables, CVP must be measured and maintained at physiologic values when rapid-infusion systems are used in children. Platelets. Platelet deficiency is the usual cause of coagulopathy after hemorrhage and resuscitation. Although surgical bleeding may occur when the platelet count is 50,000 to 70,000/mm3, there is no absolute number that relates platelet count to clinical bleeding. Each patient must be individually assessed for signs of bleeding (e.g., oozing in the surgical field). The infusion of 0.1 to 0.3 U/kg of platelets will cause an increase of 20,000 to 70,000/mm3 in the child's platelet count.'O After massive transfusion, it is not necessary to infuse platelets, as a prophylactic, in the child who is not bleeding. Because hypothermic platelets do not function properly, every effort should be made to keep children warm, especially children who are actively bleeding. Fresh-Frozen Plasma (FFP). The prophylactic administration of FFP after massive transfusion (> 1 blood volume replaced; estimated blood volume = 80 mL/kg) does not prevent clinical bleeding states that are associated with coagulopathy and should not be given merely for volume expansion. FFP is used to increase clotting factors in children with demonstrated deficiencies (PT, PTT > 150% of Because FFP and platelet concentrates contain a large amount of citrate preservative, rapid administration (> 1.5 mL/kg/min) may cause calcium binding and hypotensionP Hypotension that is secondary to citrate toxicity may be treated with calcium chloride (10 mg/kg) and the temporary discontinuation of FFP or platelet transfusion. THORACOABDOMINAL TRAUMA Abdominal Trauma Abdominal trauma is very common in the pediatric population and can be a source of significant difficulty, including failure to resuscitate. Most trauma involving the abdomen is blunt in origin, penetrating trauma being relatively rare. The relatively large liver and spleen in children make them especially vulnerable to injury and are the most commonly injured organs in the abdomen. Fracture and laceration injuries of liver and spleen are common and can be accompanied by

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significant blood loss. Until recently, patients who presented with an acute abdomen after trauma were brought immediately to the operating room for exploratory laparotomy, resulting all too often in an unstable intraoperative course. Due to tamponade of open vessels by hematoma, a fractured spleen or lacerated liver may temporarily cease to bleed. After the abdomen is opened, however, the tamponade will be released and massive bleeding may ensue. Unfortunately, massive bleeding is frequently difficult to control and may result in hypotension, a need for transfusion, and cardiac arrest. The spleen and liver are difficult to repair during the best of conditions and when massive bleeding occurs, the surgical procedure becomes very challenging. Furthermore, patients who are postsplenectomy have decreased ability to phagocytize bacteria and may develop overwhelming sepsis. For these reasons, many trauma centers now treat blunt abdominal trauma in children with nonsurgical evaluation and management if at all possible. The patient with suspected intra-abdominal pathology is initially evaluated with either CT or ultrasound imaging of the abdomen. If injury of the liver or spleen is detected, the patient may be treated medically.6 Blood is administered to maintain adequate intravascular volume and perfusion? If it is not possible to maintain adequate hemodynamic stability with blood and fluid administration, surgery is then considered. The liver or spleen are preserved if at all possible, with removal done only as a last resort. With the increased use of seat belts, there is an increased incidence of jejunal and ileal This injury is detected by the presence of free air on radiologic films, by the appearance of acute abdominal signs, or by peritoneal tap and lavage. Closure of the bowel perforation is performed surgically. Thoracic Trauma

Thoracic trauma in children is frequently the result of either a fall or a motor vehicle accident.21,27 Penetrating trauma from a knife or firearm may be seen in adolescents, but is fortunately rare in younger children. Types of chest injuries are significantly different in children than in adults, the anatomy of children producing a different pattern of injury.34Children have less bone and more cartilage in the rib cage and therefore a more elastic chest wall. As a result of these factors, there are less rib fractures in children than in adults after blunt trauma. Likewise, a flail chest is less likely in the pediatric population, and in contrast to adults, first rib fractures are not associated with significant mortality in children. After blunt chest trauma, lung contusion, and hemothorax or pneu26 Diagnosis of hemothorax mothorax are the most common inj~ries.~, and pneumothorax is similar to that in adults. After lung contusion, there may an initial period of adequate gas exchange followed by progressive impairment. There may be progressive deterioration of pulmo-

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nary function and the added risk of secondary injury from hypoxemia and acidosis. Therefore, prospective evaluation by both medical and nursing staff is important to detect and minimize the potential detrimental effects of lung contusion. Although supplemental oxygen may be the only management needed, tracheal intubation and mechanical ventilation with positive end-expiratory pressure are occasionally necessary. Flail chest is less common in children because of the elasticity of the chest wall. If flail chest occurs, management is the same as in adults. Although traumatic aortic rupture is very unusual in children, the most common presenting sign is cardiac arrest; mortality is high because recognition is late. Diaphragmatic rupture is also rare and difficult to detect. Both chest and abdominal radiographs may be inadequate to document the rupture, and diagnosis is made only during laparotomy or thoracotomy. Myocardial contusion is increasingly recognized in children and occurs when the heart is compressed between the sternum and the spine.2oElectrocardiographic currents are useful in this situation, which appears within the first 24 hours of injury in most children with significant injury. Cardiac enzymes have been used for diagnosis in some instances but are not particularly reliable. Echocardiography is useful and noninvasively determines if there is significant wall motion abnormality or depression of stroke volume. Patients with a significant contusion respond as if they have decreased myocardial contractility. Therefore, compromised myocardial contractility should be considered by administering both fluids and anesthetics. Pulmonary artery catheterization with cardiac output determinations may be useful in patients symptomatic for contusion. Other problems that can occur with cardiac contusion include valve dysfunction, traumatic septa1 defect, pericardial tamponade, and cardiac dysrhythmias. THE CHILD WITH HEAD INJURY

The mortality of children increases dramatically if multiple trauma is associated with closed head injury. Unfortunately, there is little that the anesthesiologist can do for the primary tissue-disruptive effects of head injury. Injury secondary to hypoxia, hypotension, edema, increasing ICP, and increased metabolic demand (e.g., seizures or fever) may be attenuated with appropriate care. In hypotensive children with closed head injury, hypotension is usually caused by something other than the head injury (e.g., abdominal injury). Infants may become hypotensive from a head injury because of blood loss into either the subgaleal or epidural space; however, this is an infrequent occurrence. The infant with an open fontanelle and mobile sutures is more tolerant of an expanding intracranial mass. Therefore, a bulging fontanelle in an infant who is not in coma should be treated as a severe injury. Neurologic evaluation focuses on the presence of increased ICP. Increased ICP is common in children with head injury, and occurs, most

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often, without a mass lesion. The Glasgow Coma Scale provides a fairly accurate estimate of the ICP. The verbal portion of this test has been modified for the preverbal child (Table 1).In general, an infant or child who can cry is given a full verbal score, and a child who can “wiggle, open, and answer” (i.e., a child who can wiggle his fingers and toes, open his eyes, and answer simple questions) has a Glasgow Coma Score of -12 to 15 and probably does not have raised ICP. On the other hand, a child with Glasgow Coma Score of 8 or less probably has significantly increased ICP, and the child with a score of 6 or less has increased ICP that demands immediate and aggressive intervention to prevent uncal herniation. Although children often vomit after head injury without increased ICP, persistent vomiting and recurring seizures indicate an increase in ICP. Airway Management All too often, cervical radiographs are either not available or never totally “cleared” by the radiologist, because the radiographs do not include adequate views below C6 or views of the odontoid process (a common site of fracture in children). Furthermore, pseudosubluxation of C2 to C3 (anterior displacement of C2 on C3) or C3 to C4 is common and, if this is present, could create a diagnostic dilemma (Fig. 7).17 Furthermore, children can suffer spinal cord injury, yet show no abnormality on the radiograph. Therefore, children with closed head injury should be treated as if they have unstable cervical spines. Unless these children are severely obtunded, intubation without

Table 1. GLASGOW COMA SCALE FOR INFANTS AND CHILDREN Score

4

3

2 1

Variable Best motor response Obeys commands Localizes pain Withdraws from pain Abnormal flexion Abnormal extension Flaccidity Best verbal response (modified for children) Appropriate words or social smiles, fixes and follows Cries but consolable Persistently irritable Restless, agitated (moans only) None Eye opening Spontaneous Opens to voices Opens to pain None

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Figure 7. Physiologic pseudosubluxation of C,. In both A and €3, the axis is anteriorly displaced with respect to C,, simulating subluxation or dislocation. The fact that the posterior cortex of neural arch of C, lies on the posterior cervical line (A, solid line; 6, dashed line) indicates that the forward translation of C, is physiologic. (From Harris JH, Harris WH: The Radiology of Emergency Medicine, ed 2. Baltimore, Williams & Wilkins, 1981, pp 108-1 11 ; with permission.)

anesthetic agents (”awake” intubation) is usually impractical. In addition, laryngoscopy in the awake child is a potent stimulator of intracranial hypertension. Because of the acute nasal-pharyngeal-laryngeal angles in children less than 8 years old, blind nasotracheal intubation is rarely successful, and it may result in intracranial insertion if basilar skull fracture is present. Fiberoptic intubation requires prerequisite level of skill and, even in the best of hands and static conditions, it is time consuming; therefore, it has limited use in acute trauma. In the anesthetized child whose neck is being held in neutral position by in-line stabilization, oral laryngoscopy, under direct vision, usually allows successful endotracheal intubation. When using this technique, the head and neck are maintained in anatomic alignment with the body by the insertion of the assistant’s fingertips under the child’s mastoid processes and by a gentle pulling effort in a straight cephalad line. During in-line stabilization, only slight axial traction is applied. Overly aggressive axial traction may cause further disruption of the cervical spine and should be avoided. In-line stabilization prevents the endoscopist from putting the child’s head into extreme flexion or extension. A second assistant should apply cricoid pressure. If the child arrives with a cervical stabilization device in place, it may be carefully

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removed (while maintaining in-line stabilization) to gain access to the child’s larynx. If a younger child’s relatively large occiput causes undue neck flexion that prevents adequate laryngoscopy, it is safe to cautiously place (while maintaining in-line stabilization) a small towel under the shoulders. Fluid Management

Restoration of volume in hypovolemic children with closed head injury almost always takes priority over considerations of raised ICP. To maintain perfusion to the brain and other vital organs, it is of paramount importance to maintain the child’s circulatory status. In children with head injury, as in those without head injury, any isotonic crystalloid may be used for fluid resuscitation. Colloid provides no rlinical advantage and is more expensive. Although RL is not isotonic ,XL = 273 mOsm/L compared with normal saline = 308 mOsm/L), it may be used to resuscitate the child with multiple trauma and head injury. If given to the child in large amounts before arrival in the emergency department or operating room, the serum osmolality and hematocrit should be determined, both initially and at intervals, and further fluid should be replaced with either RL, normal saline (NS), or RBCs. The administration of mannitol for diuresis may be followed by a triphasic response consisting of (1) increased blood volume, blood pressure, and possible ICP; (2) return to normal blood pressure; and (3) hypotension. Therefore, the administration of mannitol should be delayed until children are hemodynamically stable. When the patient is hemodynamically stable, loop diuretics may be given to augment the effect of mannitol. AIRWAY TRAUMA Internal Trauma (Foreign Body Aspiration)

Airway obstruction secondary to foreign body aspiration can be intrinsic (laryngeal, tracheal) or extrinsic (esophageal). Aspiration of foreign bodies is the leading cause of death in the home in children less than 6 years of age.4Aspiration of a foreign body occurs most frequently in 1- to 3-year-old toddlers who lack molars for breaking up the most commonly aspirated objects: peanuts, seeds, popcorn kernels, and carrot~.~ Intrinsic (Laryngeal or Tracheal) Foreign Body Because obstructing foreign bodies lodge in the distal airway 85% of the time, a latent period may elapse before the child becomes symptomatic. Children with distal airway foreign body obstruction are more likely to present with sneezing, coughing, and decreased air entry and

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exhibit obstructive emphysema, atelectasis, or pneumonia on chest film. By contrast, children with laryngotracheal foreign body obstruction more often present with stridor, dysphagia, dyspnea, and a normal chest film. Although plain films of the neck are usually inconclusive due to the radiolucency of most laryngotracheal foreign bodies, impacted subglottic foreign bodies may be diagnosed using rapid spot films of the airway.15 Emergency or elective removal depends on the severity of respiratory distress. An obtunded child should receive 100% oxygen and is taken directly to the operating room for awake laryngoscopy, endotracheal intubation or bronchoscopy. If the child has a full stomach and is not in respiratory distress, one may wait 4 to 6 hours to decrease the risk of aspiration. If the child has a full stomach and is in mild to moderate respiratory distress, bronchoscopy should be performed without delay. General anesthesia with spontaneous ventilation is generally preferred for bronchoscopy because this technique maintains the airway, obviates short-acting muscle relaxants and positive pressure ventilation, provides optimal conditions for the bronchoscopist, and allows detection of conversion from partial to complete airway obstruction. The induction of anesthesia with IV agents may be appropriate, especially in the child with a full stomach. The major risk of IV induction with muscle relaxation and positive pressure ventilation is that the foreign body may be pushed further into the airway where it may be less accessible, may create a ball-valve obstruction, or may obstruct both bronchi. The bronchoscopist should always be present at the induction of anesthesia. During the foreign body removal, deep anesthesia is maintained with halothane and oxygen. Succinylcholine must be immediately available in the event that vocal cord relaxation becomes necessary to facilitate removal of a large foreign body or to be used as a measure of last resort if laryngospasm occurs. Atropine, 0.02 mg/kg IV, is included in the premedication to dry secretions and because administration of IV succinylcholine may be necessary. Extrinsic (Esophageal) Foreign Body Obstruction

Anesthesia for removal of a foreign body in the esophagus depends on the contour of the object swallowed. If the foreign body has a smooth contour, rapid sequence induction with cricoid pressure and orotracheal intubation is preferred; however, if the foreign body is sharp or jagged, general anesthesia is to be induced in the lateral head down position using spontaneous ventilation without cricoid pressure. External Trauma (Cricothyroid Separation) Although protected from fracture by its pliability, the pediatric larynx can sustain cricothyroid ~eparati0n.l~ Because external damage may be minimal, cricoid separation is suspected in the injured child

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who presents with dysphonia, dysphagia, stridor, hemoptysis, or subcutaneous emphysema. Evaluation of the child includes cervical films (soft tissue and spine), chest films, barium swallow, and CT scan of the neck. Because cervical spine injury may be present, laryngoscopy is performed in the neutral position. If the vocal cords and subglottic area are visualized during laryngoscopy, intubation is performed. If the vocal cords and subglottis are obscure, tracheostomy is performed. Blind endotracheal intubation is contraindicated.

SUMMARY

The traumatized pediatric patient may be aided by prevention, intervention, and legislation (e.g., laws requiring air bags in automobiles). Whereas prevention of trauma is the concern of everyone, intervention primarily concerns the well-prepared health care provider who strives to affect a positive outcome.

References 1. American College of Surgeons: Advanced Trauma Life Support Student Manual. Chicago, American College of Surgeons, 1989, p 222 2. Badgwell JM, McLeod ME, Lerman J, et a 1 End-tidal PCO, measurements sampled at the distal and proximal ends of the endotracheal tube in infants and children. Anesth Analg 66:959-664, 1987 3. Bissonnette 8, Sessler D I Passive or active inspired gas humidification increases thermal steady-state temperatures in anesthetized infants. Anesth Analg 69:783, 1989 4. Blazer S, Naveh Y, Freidman A: Foreign body in airway: A review of 200 cases. Am J Dis Child 68-72, 1980 5. Chalon J, Pate1 C, Ali M et al: Humidity and the anesthetized patient. Anesthesiology 50:195-198, 1979 6. Cogbill TH: Nonoperative management of blunt splenic trauma: A multicenter experience. J Trauma 29:1312-1317, 1989 7. Colombani PM, Buck JR, Dudgeon DL, et al: One-year experience in a regional pediatric trauma center. J Pediatr Surg 208-13, 1985 8. Cosentino CM, Luck SR, Barthel MJ, et a1 Transfusion requirements in conservative nonoperative management of blunt splenic and hepatic injuries during childhood. J Pediatr Surg 25:950-954, 1990 9. Cote CJ, Drop LJ, Hoaglin DC, et al: Ionized hypocalcemia after fresh frozen plasma administration to thermally injured children: Effects of infusion rate, duration, and treatment with calcium chloride. Anesth Analg 67152-160, 1988 10. Cote CJ, Liu LMP, Szyfelbein SK, et al: Changes in serial platelet counts following massive blood transfusion in pediatric patients. Anesthesiology 62:197-210, 1985 11. Crino MH, Nagel EL Thermal burns caused by warming blankets in the operating room. Anesthesiology 29:149-151, 1968 12. Ferguson M, Max MH, Marshall W: Emergency department infraclavicular subclavian vein catheterization in patients with multiple injuries and burns. South Med J 81:433437, 1988 13. Fildes J, Sheaff C, Barrett 1: Core rewarming with very hot intravenous fluids. J Trauma 35:683-687, 1993 14. Fiser DH: Intraosseus infusion. N Engl J Med 322:1579-1581, 1990

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15. Gay 88, Atkinson GD, Vanderzalm T, et al: Subglottic foreign bodies in pediatric patients. J Dis Child 140:165-168, 1986 16. Harris H H Management of injuries to the larynx and trachea. Laryngoscope 82:19251929, 1972 17. Harris JH, Harris W H The Radiology of Emergency Medicine, ed 2. Baltimore, Williams and Wilkins, 1981, pp 108-111 18. Hynson J, Sessler DI: Intraoperative warming therapies: A comparison of three devices. J Clin Anesth 4:194-199, 1992 19. Joacchimsson PO, Hedstrand U, Tabow F: Prevention of intraoperative hypothermia during abdominal surgery. Acta Anaesthesiol Scand 31:330-337, 1987 20. Langer JC, Winthrop AL, Wesson DE: Diagnosis and incidence of cardiac injury in children with blunt thoracic trauma. J Pediatr Surg 24109-1094, 1989 21. LoCicero J, Mattox KL: Epidemiology of chest trauma. Surg Clin North Am 69:15-19, 1989 22. Moayeri A, Hynson JM, Sessler DI, et al: Pre-induction skin-surface warming prevents redistribution hypothermia. Anesthesiology 75A1004 (abstr), 1991 23. Murray DJ, Forbes RB, Mahoney LT: Comparative hemodynamic depression of halothane versus isoflurane in neonates and infants: An echocardiographic study. Anesth Analg 74:329-337, 1992 24. Newman KD: The lap belt complex: Intestinal and lumbar spine injury in children. J Trauma 301133-1138,1990 25. NIH Consensus Conference: Fresh-frozen plasma: Indications and risks. JAMA 253551, 1985 26. Peclet MH, Newman KD, Eichelberger MR, et al: Patterns of injury in children. J Pediatr Surg 25:85-91, 1990 27. Peclet MH: Thoracic trauma in children: An indicator of increased mortality. J Pediatr Surg 25:961-966, 1990 28. American Society of Anesthesiologists, Committee on Transfusion Medicine: Questions and Answers About Transfusion Practices, ed 2. Dallas, American Society of Anesthesiologists, Committee on Transfusion Medicine, 1992, p 24 29. Seidel JS, Burkett DL: Instructors Manual for Pediatric Advanced Life Support. Dallas, American Heart Association, 1988 30. Sessler DI, Moayeri A: Skin surface warming: Heat flux and central temperature. Anesthesiology 73:218-224, 1990 31. Shires GT, Canizaro PC, Carrico CJ: Shock. In Schwartz SI: Principles of Surgery, ed 3. New York, McGraw-Hill, 1979, pp 139-144 32. Shires GT, Coln D, Carrico J, et al: Fluid therapy in hemorrhagic shock. Arch Surg 88:688-693, 1964 33. Shires GT, Cunningham JN, Baker CRF, et al: Alterations in cellular membrane function during hemorrhagic shock in primates. Ann Surg 176:288-295, 1972 34. Snyder CL, Jain VN, Saltzman DA, et al: Blunt trauma in adults and children: A comparative analysis. J Trauma 30:1239-1245, 1990 35. Weiskopf RB, Bogetz MS, Roizen MF, et al: Cardiovascular and metabolic sequelae of inducing anesthesia with ketamine or thiopental in hypovolemic swine. Anesthesiology 60:214-219, 1984

Address reprint requests to J. Michael Badgwell, MD Associate Professor of Anesthesiology and Pediatrics Texas Tech University Health Sciences Center 3601 Fourth Street Lubbock, TX 79430