pediatric trauma

Management principles of pediatric trauma patients

Management principles of pediatric trauma patients are similar to those of adults, but modified according to the age group of the child. Children are not just small adults. Their unique, developing psychologic, anatomic, and physiologic characteristics pose special challenges to anesthesiologists and the entire trauma care team. Optimal management of the pediatric trauma patient depends on adequate knowledge and

understanding of these unique characteristics.

INITIAL ASSESSMENT AND MANAGEMENT

Primary Survey

The main goal of the primary survey is to rapidly find all potentially life-threatening injuries to prioritize management for efficient resuscitation and achieve hemodynamic stability. This requires immediate assessment of the “ABCDEs” of the Advanced Trauma Life Support (ATLS) protocol and constant reevaluation of the adequacy of resuscitation strategies.

Airway with C-Spine Control

Evaluation of the airway in an injured child can be complex. Injury to the airway or nearby structures may distort normal anatomy and render mask ventilation and tracheal intubation difficult.Preexisting conditions thatmay complicate emergency

airway management include congenital abnormalities, such as micrognathia (mandibular hypoplasia), macroglossia, and cleft palate and the presence of obstructive sleep apnea with or without obesity.

Inspection of the airway includes the face, mouth, mandible, nose, and neck. Look for edema, foreign bodies, secretions, blood, loose or missing teeth, and fractures of the jaw, mandible, and cervical spine. Any trauma victim, especially one with a closed-head injury, is presumed, until proved otherwise, to have cervical spine (C-spine) injury and a full stomach.

C-spine precautions

should be maintained and techniques that minimize the risk of pulmonary aspiration should be taken at all times.

Healthy neonates and young infants have large heads, including prominent occiputs relative to body size, so that, in the supine position, the infant neck is naturally flexed on the chest and the supine infant headmay be flexed on the neck]. This has several important implications.

The natural head and neck flexion of the obtunded or sedated young infant often results in significant airway obstruction that may be relieved by gently lifting the chin up and forward (anteriorly) to slightly extend the head on the neck. Otherwise, an

oral airway can be inserted with no relative movement of head and neck. In suspected C-spine injury, a more neutral, straight head and neck position should be achieved by placing a blanket or pad under the supine infant or young child’s torso.

Neonatesandyounginfants areobligate nose breathers until three to five months of age so that any secretions or blood in their relatively narrow nasal passages can lead to airway obstruction.

The larynx in infantsandchildren ismore cephalad, approximately at the level of the C3–C4 vertebrae in infants compared with the C5–C6 level in adults. This may give the impression that the infant larynx is more anterior during direct laryngoscopy.

The length of the trachea is only 4–5 cm in infants and approximately 7 cm by 18 months of age, so right mainstem intubation or ETT dislodgement can occur with correspondingly small movements of the infant’s head. extubation.When choosing the appropriately sized ETT, keep in mind that in children less than 5 years old, the narrowest part of the upper airway is at the level of the cricoid cartilage, not at the glottis, as in adults. The size of the ETT appropriate for the patient’s age may

be estimated by comparing the tube size with that of the infant or child’s fifth finger, or by using the formula: ETT tube size (diameter in mm) = 4 + (1/4) age .

An air leak around the ETT at 15–20 cmH2Opressure and easy passage of the tube into the trachea clinically suggests that the ETT size is appropriate. The following formula may be used as a guide to determine the appropriate depth of the ETT placement (in centimeters from lips to tip of ETT) for children older than 2 years: 13 + (1/2) age); for under 1 year old: 8 + weight in kilograms [20].

The appropriate depth of ETT insertion may also be approximated bymultiplying the internal diameter (millimeters) of the ETT by 3.

Indications for Endotracheal Intubation

a. Loss of consciousness or altered level of consciousness with inability to protect the airway

b. Inability to maintain patency of airway or clear secretions

c. Provide positive pressure ventilation and adequate oxygenation

d. Significant burn with airway injury.

Cervical Spine Injury

Cervical spine fractures are less likely in children than adults because of the greater mobility of the spine and relative laxity of the ligaments present in children. Pediatric cervical spine injuries are different from adult injuries (until the age of 8– 10 years), resulting mainly from anatomical differences. Children have relatively underdeveloped neck muscles and large heads in proportion to their bodies. Children’s vertebral bodies are wedged anteriorly and tend to slide forward with flexion.

Younger children have horizontally angled or flat articulating facets, cartilaginous endplates, and elastic, lax interspinous ligaments. These characteristics predispose children to upper cervical injuries, spinal cord injury without radiographic evidence of abnormality (SCIWORA), and severe ligamentous injuries.

C-spine injuries in children less than 8 years old aremore commonly at the C1–C3 level because of the more horizontal facets.

Because up to two thirds of children with spinal cord injury have normal spine x-rays, careful history and neurologic exam are essential in its diagnosis. Pseudosubluxation of cervical vertebrae (C2–C3) and incomplete ossification are normal findings that may contribute to the difficulty in diagnosing spinal cord injuries in children.

Anteroposterior and lateral cervical spine radiographs are fundamental imaging studies for spine clearance. Computed tomography (CT) is a useful adjunct providing more definition of bony abnormalities. Magnetic resonance imaging (MRI) has been used to detect ligamentous and soft tissue injuries, the extent of spinal cord injuries, and the presence of hematoma formation, and herniated disks not visualized by other imaging modalities.

Patients should be maintained supine on a rigid backboard, with head blocks or sandbags on each side of the head strapped securely onto the backboard, and a rigid cervical collar in place to minimize neck flexion and extension.

If the need for tracheal intubation arises, the patient should be preoxygenated with 100 percent oxygen, and manual inline stabilization of the head and neck without traction should be maintained by one trained person while another trained provider performsa rapid sequence induction intubation.

Breathing and Ventilation

To evaluate breathing and assess ventilation, look for abnormalities in respiratory rate and pattern, the presence of stridor, grunting, nasal flaring, sternal, intercostal or subcostal retractions, head bobbing, and the use of accessorymuscles of respiration.

Observe the chest for symmetry of expansionandparadoxical or “rocking boat” pattern of breathing that suggests airway obstruction, and listen for bilateral and equal breath sounds in the axillary areas. End-tidal carbon dioxide (ETCO2) monitoring is a valuable tool for providing information about carbon dioxide retention and adequacy of ventilation.

Circulation and Hemorrhage Control

Recognition of shock and identification of probable cause may be critically important. Treatment goals are prompt control of hemorrhage and restoration of organ perfusion and tissue oxygenation.

Initial assessment includes blood pressure, pulse rate and rhythm, and peripheral pulses and perfusion. Delayed capillary refill (longer than 2 seconds), cool extremities, cyanosis, and skin mottling are signs suggestive of poor perfusion.

Immediate restoration of circulating blood volumetomaintain adequate blood pressure, cardiac output, and perfusion of vital organs is crucial. Initial resuscitation includes the administration of warmed isotonic crystalloid solution, preferably lactated Ringer’s as a 20 mL/kg bolus, which may be repeated once or twice. If the child remains hemodynamically unstable despite aggressive crystalloid fluid resuscitation, administration of colloids and blood products should be strongly considered.

Type-specific, cross-matched packed red blood cells (PRBCs), in 10–20 mL/kg increments, are preferable, but if fully crossmatched blood is not immediately available, type-specific, partially cross-matched PRBCs or type-specific unmatched blood can be given. Otherwise, type O Rh-negative PRBCs can be givenuntil type-specific blood is available.

Favorable signs suggestive of adequate response to volume resuscitation include return of normal blood pressure, pulse pressure greater than 20 mmHg, pulse rate and skin color approaching normal, improvement in level of consciousness and acid-base status, and adequate urine output. Placement of a urinary catheter allows accurate monitoring of urine output and facilitates assessment of the response to volume resuscitation. Adequate urine output is generally considered to be 2 mL ・ kg−1 ・ hr−1 in infants (less than 1 year old), 1 mL・ kg−1 ・ hr−1 in children, and 0.5 mL・ kg−1 ・ hr−1 in adolescents and adults.

Vascular Access

In pediatric trauma patients with hypovolemia or shock, obtaining peripheral IV access can be a nightmare, even in the most experienced hands. The hypovolemic child needs at least two relatively largebore peripheral IV lines: 22 G for newborns and infants up to 3years old, 20Gfor children 4 to 8 years old, 20 or 18Gfor those older than 8 years. Vascular access may be obtained peripherally or centrally, percutaneously or by cutdown, or through an intraosseous (IO) route.

Preferred Sites for Venous Access in Children [5]

1. Percutaneous peripheral

2. Intraosseous

3. Percutaneous femoral

4. Venous cutdown: saphenous vein

5. Percutaneous external jugular vein

Central line (internal jugular or subclavian vein) cannulation is not recommendedfor primary IV access due to risks of pneumothorax and hemothorax and because the head and neck should not be manipulated if cervical spine injury has not been ruled out.

If percutaneous venous access, the preferred route, is not established in three attempts or in 90 seconds, placement of an IO needle should be considered [5]. The intraosseous route is a simple, reliable, and effective alternative when peripheral intravascular access is difficult to obtain, especially in children less than 6 years old.

Disability/Neurologic Evaluation

Disability refers to the initial neurologic evaluation thatwill serve as the basis for comparison to subsequent assessments.

The mnemonic “AVPU” refers to awareness (A), response to verbal (V) stimuli and pain (P), and unresponsive to stimuli (U).

The classic Glasgow Coma Scale (GCS) used in adults for initial assessment of neurologic status and prognosis is not very reliable in children of all ages. It has been shown that in the absence of ischemic-hypoxic injury, children with severe traumatic brain injury and unfavorable GCS score (GCS 3 to 5) can recover independent function [32]. To be applicable to infants and young children, the GCS verbal scoring has been modified (see Table 24.6). A more general Pediatric Trauma Score (PTS) may be used for triage purposes.

Glasgow Coma Scale (GCS)

Response Score

Eye Opening

Spontaneous 4

To shout/speech 3

To pain 2

No response 1

Motor Response

Spontaneous/obeys commands 6

Localizes pain 5

Flexion withdrawal 4

Decorticate posturing 3

Decerebrate posturing 2

No response 1

Verbal Response Modified for Children

Appropriate words, social smile, fixes and follows 5

Cries, consolable/inappropriate words 4

Persistently irritable/incomprehensible words 3

Restless, agitated, moans 2

No response 1

Pediatric Trauma Score (PTS)

Variable          +2                +1                           –1

Weight (kg)     >20        10–20                         <10

Airway patency      normal   maintained           unable to maintain

 Systolic BP in mmHg  >90        50–90            <50

Neurologic status   awake    obtunded               comatose

Open wound      none        minor                          major/penetrating/ burns

Skeletal trauma            none      closed               open/multiple

PTS: 9–12, minor trauma; 6–8, potentially life threatening; 0–5, life-threatening; <0, usually fatal.

Exposure/Environmental Control

Traumatized children should be completely undressed to facilitate thorough examination. Infants and children lose body heat quickly because they have large surface areas relative to bodyweight, thinner skinwith less subcutaneous fat, and higher metabolic rates. Temperature must be closely monitored andmeasures should be taken to keep pediatric trauma patients warm. Ambient room temperature should be adjusted to more than 24◦C, even before the child’s arrival. Warm blankets may be used to cover all exposed areas after the initial assessment.

Forced-air convective heating blankets have been shown to bean effective method to prevent hypothermia [33]. All fluids and blood products should be infused through fluid warmers (see also Chapter 29). Transfusing cold blood rapidly through a central line may lead to arrhythmias.

Secondary Survey

The secondary survey includes a thorough evaluation of each organ system, a head-to-toe examination of the injured patient, and reevaluation of hemodynamic parameters. The following information can be obtained by using the mnemonic AMPLE: allergies (A), medications (M), past medical and surgical histories (P), last meal (L), and events (E) related to the injury. Additional indicated diagnostic procedures should be performed according to clinical need and ATLS approach. Consultation with other services is done as necessary.

ANESTHETIC CONSIDERATIONS

Preoperative Evaluation

The trauma anesthesia team should be involved early in the care of the pediatric trauma patient to maximize efficiency and optimize adequate operating room (OR) preparation and availability. Preoperative evaluation starts with the history and physical exam.

Understanding the physiologic, anatomic, and pharmacologic characteristics of pediatric patients, and how certain aspects of pediatric trauma differ from adult trauma, contributes to safe conduct of anesthesia and may improve outcome. Specific modification of anesthetic techniques and equipment may be required. Major anesthetic considerations in the management of urgent surgery in the pediatric trauma patient include the presence of gastric contents (“full stomach”), airway management, monitoring, anesthetic agents, and fluid and blood resuscitation.

Intraoperative Management

anesthesia for the pediatric trauma patient. The decision making should be influenced by the type and severity of injury, preoperative airway management, anticipated airway difficulty, hemodynamic stability, and neurologic status of the patient.

Monitors

provide useful information that can aid in the timely application of necessary therapeutic interventions. Standard monitors include noninvasive arterial blood pressure, ECG, pulseoximeter, expiratory capnogram, precordial or esophageal stethoscope, temperature probe, and FiO2 monitor. The pulse oximeter measures arterialoxygen saturation and evaluates adequacy of oxygenation and peripheral tissue perfusion. In the presence of vasoconstriction due to hypovolemia, hypothermia, or shock, pulse oximetry becomes unreliable. ExhaledCO2 monitoring, capnography, is used toconfirmendotracheal intubation, follow the adequacy of ventilation and effectiveness of cardiopulmonary resuscitation (CPR) (closely related to pulmonary blood flow and cardiac output), and estimate arterial partial pressure of carbon dioxide (PaCO2).

 Invasive monitors to consider include an arterial line, a centralvenous catheter, a urinary catheter, and/or an ICP monitoring device.

Induction of Anesthesia

All trauma patients are presumed to have full stomachs and many are at risk for having cervical spine injuries as well. Rapid sequence intravenous induction and intubation with manual in-line cervical spine stabilization is generally indicated.

It begins with preoxygenation using 100 percent oxygen for three to five minutes or four maximal breaths, followed by intravenous injection of an anesthetic induction agent and a muscle relaxant while a trained assistant applies cricoid pressure as the child loses consciousness. Direct laryngoscopy is performed as soon as the muscle relaxant has taken effect.

In-line spine stabilization is maintained throughout. Once the induction agent andmuscle relaxant are given, manual ventilation by facemask is generally avoided unless there is concern for hypoxia and hypercarbia. ETT placement is confirmed by continuous presence of a normal ETCO2 capnogram, auscultating bilateral equal breath sounds in the axillary areas, and absence of gastric sounds in the stomach. Cricoid pressure is maintained until ETT tube placement has been confirmed and the ETT cuff inflated.

Alternatively, inhalation induction can be used in a combative child with cricoid pressure applied as the child loses consciousness. laryngoscopy, is anticipated, spontaneous ventilation may be maintained while an inhalational agent is used to deepen the level of anesthesia in preparation for a fiberoptic-assisted intubation. In this case, adequate bag-mask ventilation should be confirmed prior to administering amuscle relaxant. Fiberoptic intubation allows visualization of the glottis without any neck movement, but the presence of blood and debris in the airway may make visualization difficult. If difficult airway was unexpected, an LMA can usually be easily and quickly inserted to reestablish or maintain oxygenation and ventilation until a more definitive airway can be established. An LMA may also be used as a conduit to facilitate fiberoptic tracheal intubation.

A hypovolemic child is sensitive to the vasodilating and negative inotropic effects of volatile anesthetic agents, barbiturates, and other drugs associated with histamine release, such as morphine, meperidine, atracurium, and mivacurium. The key to safe anesthetic management of the hemodynamicallyunstable pediatric trauma patient is the administration of relatively small incremental doses of any selected agents. Anesthetic induction agents are effective in reduced doses because the hypovolemic child has a decreased volume of distribution while blood flow to the brain and heart are maintained close to normal, and because concentrations of drug-binding serum proteins are reduced by the dilutional effects of fluid resuscitation.

Any of the major intravenous induction agents can be used as long as the chosen agent is titrated carefully to minimize deleterious effects. Sodium thiopental (3–6 mg/kg IV) causes myocardial depression and venodilation; therefore, cautious and slow intravenous titration is necessary to minimize significant decreases in blood pressure in the hypovolemic patient.

It is a good choice in children with head injury and increased intracranial pressure because it causes dose-dependent decreases in cerebral oxygen consumption, cerebral blood flow, and ICP and reduces epileptiform activity. Induction doses of propofol (2–3 mg/kg IV) may also be expected to decrease arterial blood pressure due to a decrease in systemic vascular resistance, cardiac contractility, and preload. Propofol has more pronounced hypotensive effects than thiopental especially in inadequately hydrated patients (see also Chapter 8). A major clinical disadvantage with propofol is pain on injection especially when given into the small veins of infants and children. Propofol may, therefore, not be the best choice for rapid sequence induction.

Ketamine may be the ideal anesthetic induction agent for the hypotensive, hypovolemic, severely injured childwho needs urgent or emergent surgery to control hemorrhage. An induction dose of ketamine, followed by a continuous maintenance infusion,may actually elevate and help maintain blood pressure while providing complete anesthesia including analgesia and amnesia.

Ketamine causes some increase in salivation thatmay be attenuated by an anticholinergic premedication, suchas atropine (0.01–0.02 mg/kg IV) or glycopyrrolate (0.01 mg/kg IV). Ketamine has been reported to increase IOP [45]. Ketamine has also been shown to increase ICP [46], cerebral oxygen consumption, and cerebral blood flow and thus is usually avoided in patients with space-occupying intracranial lesions.

Succinylcholine (1.5–2 mg/kg IV) is a depolarizing muscle relaxant and may be the drug of choice for intravenous rapid sequence induction and endotracheal intubation because of its rapid onset (30–60 seconds) and brief duration of action (5–10)min Succinylcholine transiently increases IOP, intragastric and lower esophageal sphincter pressures, and ICP. Hyperkalemic cardiac arrest has occurred after succinylcholine administration to children with undiagnosedmyopathy.Succinylcholine is contraindicated in patients with muscular dystrophies, major denervation injury, burns more than 24 hours old, a history of malignant hyperthermia, disuse atrophy, neuromuscular disorders, prolonged immobility with disease, and hyperkalemia.

Rocuronium is a nondepolarizing muscle relaxant frequently used as an alternative to succinylcholine. Larger doses of rocuronium (0.9–1.2 mg/kg IV) are required to facilitate rapid onset of neuromuscular blockade for intubation. These doses of rocuronium may prolong its duration of action to as much as 90 minutes. Rocuronium does not cause histamine release.

Vecuronium is another nondepolarizing muscle relaxant that does not cause histamine or adverse cardiovascular effects. Its onset of action is slower than that of rocuronium. Vecuronium, 0.25 mg/kg IV, provides good intubating conditions in 60–90 seconds.

Maintenance of Anesthesia

The overall clinical status of the injured child, associated injuries, the nature of the surgical procedure, and postoperative ventilatory needs of the child dictate the choice of technique and selection of agents used in the maintenance of anesthesia. A balanced general anesthetic using volatile agents, opioids, and muscle relaxants may be used for maintenance in hemodynamically stable patients. A narcotic-based anesthetic technique, using fentanyl or remifentanil with muscle relaxant, and an amnestic agen twould be more appropriate for unstable patients who cannot tolerate volatile agents. Sevoflurane, isoflurane, and nitrous oxide are inhalational anesthetic agents widely used in pediatric anesthesia.

Hypotensive pediatric trauma patients may not tolerate even reduced concentrations and doses of anesthetic agents.

Amnestic agents such as benzodiazepines or scopolamine may be administered to help prevent recall or intraoperative awareness.

Anopioid-based anesthetic technique, supplemented with carefully titrated volatile agents, may bewell tolerated. Fentanyl provides good analgesia and maintains hemodynamic stability.

Rapid changes in the ventilatory and hemodynamic status can occur intraoperatively, so constant vigilance is imperative.

Positive pressure ventilation may expand a small undiagnosed pneumothorax leading to compromised circulation, oxygenation, and ventilation. Lung contusion may lead to progressive hypoxemia and hypercarbia.Occult bleeding can result in unexplained

hypotension and shock.

Large amounts of intravenous fluids may be required to replace body fluid deficits and blood loss during surgery. Isotonic crystalloid solution is the intravenous fluid of choice for initial replacement of fluid losses associated with hemorrhagic shock, major surgery, and trauma to rapidly restore circulating blood volume and vital organ perfusion. Intraoperative fluid Managemen tincludes replacementof preoperative deficits, provision of maintenance fluids, and replacement of ongoing blood

loss and third-space losses.

An accurate estimate of preoperative blood loss in pediatric trauma patients is difficult, if not impossible. To estimate the intraoperative maintenance for pediatric patients, the “4- 2-1 rule” formula  is commonly used.

Glucose-containing solutions should be avoided, unless necessary in cases of hypoglycemia or in patients at risk for hypoglycemia, for example, neonates.

Third-space fluid losses depend on the severity of the injury and the extent of the surgery. The composition of this third-space fluid is similar to that of extracellular fluid, so balanced salt solution is again the preferred fluid for replacement.

An accurate estimate of actual fluid loss is impossible, so fluid replacement should be guided by cardiovascular response and urine output. A guideline commonly used is

Replacement of Third-Space and Evaporative

Surgical Fluid Losses

Surgical Trauma Fluid Replacement (mL ・ kg−1 ・ hr−1)

Minimal 1–2

Moderate 4–6

Severe 6–10

Indications for blood transfusion are similar to those in adults. The decision to transfuse will be influenced by preoperative hematocrit (Hct), estimated blood volume (EBV), the presence and nature of coexisting illnesses, rate of bleeding,

and the clinical response of the patient to volume resuscitation.

Maximum allowable blood loss (MABL) may be calculated as:

MABL = (initial hematocrit – target hematocrit) Initial hematocrit × EBV

To estimate the amount of PRBCs needed to reach the targeted hematocrit value, the following formula may be used:

Volume of PRBCs (mL) = desired hematocrit – present hematocrit hematocrit of PRBC (approximately 60%) × EBV

FFP (10–15 mL/kg) is indicated to treat coagulopathy.

Emergence and Postoperative Considerations

Children with minor injuries can be extubated at the end of the procedure if the following criteria are met: child is awake and alert, vital signs are stable without any

inotropic support, and the child is euthermic and maintaining adequate oxygenation and ventilation with spontaneous respirations and reversal of neuromuscular blockade. If the decision has been made to keep the child intubated, then transport to the intensive care unit must be carefully planned. Transport monitors, full oxygen tank and ambu-bag, emergency airway equipment, fluids, and resuscitation drugs should be readily available. Cervical spine precautions should be maintained throughout and reassessment of the adequacy of oxygenation and ventilation should be confirmed every time the patient is moved.