Children are commonly involved in accidents; trauma is the leading cause of death between 1 and 14 years of age. Even if the injury is relatively minor, some children require emergency anesthesia, the potential dangers of which may overshadow the injury.
Most children injured in accidents were previously healthy. Therefore considerations of past health are usually less important than in the adult. However, a complete medical history must be obtained as soon as possible. From the time of arrival in the emergency department, the anesthesiologist must be included in the treatment team. The anesthesiologist can contribute to immediate care while evaluating the child’s condition for anesthesia and the need for further continuing care.
Major Trauma
Diagnosis and treatment must proceed rapidly and simultaneously. Vigorous resuscitative measures must be continued without interruption during anesthesia. The common major problems for the anesthesiologist include:
- 1.
To secure and maintain a safe, reliable airway and to optimize ventilation and oxygenation
- 2.
To achieve adequate blood and fluid replacement
- 3.
To optimize cerebral perfusion pressure in children with a head injury
- 4.
To maintain body temperature
N.B. Injuries are often multiple. Although injuries may appear to be limited to a single anatomic site or body system, the possibility of serious injuries elsewhere must constantly be kept in mind. The fractured femur may be an obvious injury, but the as yet undiagnosed ruptured liver could be the greater threat to life.
Initial Urgent Procedures
- 1.
Ensure a safe and protected airway, and optimize ventilation and oxygenation.
- 2.
The cardiovascular status must be determined:
- a.
If hypovolemia is present, it must be corrected.
- b.
Effective cardiac output must be maintained or restored.
- a.
- 3.
Blood is withdrawn without delay for type and cross-match. The blood bank should be advised immediately if a massive transfusion is likely to be necessary.
Establishing the Airway
Airway obstruction is common in head and facial injuries and can have a disastrous effect on the outcome.
- 1.
All children with head injury should be given oxygen by mask immediately on admission.
- 2.
For those with depressed consciousness, if simple positioning does not provide a clear airway or if the gag reflex is absent, intubate the trachea without delay.
- 3.
Do not insert oropharyngeal airways in unconscious children. Resistance to ventilation is greater than with an endotracheal tube and they do not protect against aspiration of gastric contents.
- 4.
Injury of the cervical spine must be suspected in all trauma; immobilize the neck using sandbags, a plaster shell, or a bean bag. *
* Vac-Pac surgical positioning system, VenTech Healthcare Inc., Toronto.
Avoid moving the neck. Note that a cervical spine injury may occur without any radiologic evidence (known as SCIWORA, s pinal c ord i njury w ithout r adiographic a bnormalities). Optimal airway management must be the first priority, but caution concerning cervical spine injury is required (see later discussion).
- 5.
Be alert to the possibility of foreign bodies (i.e., teeth, bone fragments) in the mouth, pharynx, trachea, or bronchi, especially if there are facial injuries.
- 6.
“Awake” laryngoscopy and intubation can markedly increase intracranial pressure (ICP), which may be detrimental in the head-injured child. In children with suspected increased ICP, administer a general anesthetic with RSI: give IV lidocaine 1 to 2 mg/kg, propofol 2 to 3 mg/kg, or thiopentone 5 mg/kg; atropine 0.02 mg/kg; and succinylcholine 1 to 2 mg/kg before intubation. This regimen cannot, however, be safely followed if the child is hypovolemic; in such instances, ketamine (use cautiously with increased ICP), etomidate or midazolam (with IV lidocaine for the latter two) should be used for induction. All trauma patients must be assumed to have a full stomach, and an RSI should be used to secure the airway. Succinylcholine does not increase intragastric pressure in young children and therefore does not increase the risk of regurgitation. Succinylcholine does not increase ICP significantly and the advantages of rapidly securing a safe and clear airway and instituting controlled ventilation are more important. Beware of neck injury; stabilize the spine. (Remember: a cervical spine injury is a relative contraindication to cricoid pressure.)
- 7.
Vomiting and aspiration commonly occur after an accident. Immediately after intubation, check air entry to all lung regions and suction via the endotracheal tube if necessary. Examine chest radiographs for tracheal tube position and evidence of pathology.
- 8.
A gastric tube should be passed to decompress the stomach, especially in those with chest or abdominal injuries in whom acute gastric dilation is common. Even children with relatively minor injuries often swallow enough air to cause significant gastric distention; this interferes with ventilation and predisposes to vomiting and aspiration. Do not pass a tube through the nose in children who may have a basal skull fracture.
- 9.
Be alert to the possibility of pneumothorax or hemothorax.
Intravenous Therapy
Large-bore intravenous lines must be established. These must be placed in the upper limbs or neck in children with injuries at the level of the thorax and below because flow through the inferior vena cava may be (or become) compromised. All intravenous fluids should be warmed; hypothermia may rapidly develop in the injured child.
Percutaneous cannulation of large veins, using at least 20-gauge catheters, is preferable. Alternatively, a cut-down or an intraosseous needle may be required. Internal jugular or subclavian lines may be inserted if no other venous access is available; beware of further worsening the cardiorespiratory status if a pneumothorax or hemothorax occurs. A central venous catheter will be useful during the further management of the child, but it may be inserted after the initial acute fluid resuscitation (avoid IJ lines in head-injured children).
Clues to blood volume status are as follows:
- 1.
Cardiovascular indices:
- a.
Tachycardia suggests hypovolemia in children of all ages. A heart rate in excess of 140 beats/min in infants or 100 beats/min in older children is suggestive.
- b.
In infants, the systolic blood pressure (BP) varies in parallel with the intravascular volume and is a very good guide to volume status.
- c.
In older children, as in adults, hypovolemia stimulates early constriction of venous capacitance vessels. Therefore the systolic BP may remain near normal, despite a loss of up to 20% of the blood volume. The central venous pressure (CVP) may also be maintained initially. When such vasoconstriction can no longer compensate and maintain the venous return to the heart, rapid decompensation may occur. At this point the CVP decreases and becomes a more reliable guide to the adequacy of replacement of the blood volume. A 2 to 3 mm Hg fall in CVP may represent as much as 25% of the circulating blood volume in a healthy, supine child.
- a.
- 2.
General appearance: Pallor, mottling, sweating, and coolness of the skin, especially over the extremities, are signs of hypovolemia. The latter can be quantified by simultaneous measurement of skin and body core temperatures: a large difference indicates vasoconstriction, and lessening of the difference indicates improving skin perfusion as blood volume increases toward normal.
- 3.
Confusion and irrational behavior are common signs of hypovolemia in children.
- 4.
Urine output: The severely injured child should be catheterized and the urine output monitored. A urine flow of more than 1 ml/kg/hr indicates adequate renal perfusion and adequate volume replacement.
- 5.
Biochemical studies: Metabolic acidosis (lactic acidosis) may result from impaired organ perfusion and is a confirmatory sign of a low circulating blood volume. This acidosis may be corrected by adequate volume replacement. Sodium bicarbonate administration is not recommended except for severe acidosis that may compromise cardiac action (i.e., pH <7.2 despite normocapnia or hypocapnia).
Selection of Fluids for Infusion
The types of fluid depend on (1) what is indicated and (2) what is available.
Frequently, initial fluid resuscitation includes balanced salt solutions rather than blood products. If at all possible, do not transfuse non–cross-matched universal donor blood. (A rapid cross-match can be performed in 20 minutes.) If blood loss is massive, and is in the chest cavity, consider autotransfusion.
A balanced salt solution (e.g., lactated Ringer’s solution) can be used initially to expand the circulating blood volume, but if used to excess (more than 100 ml/kg), it may lead to pulmonary insufficiency and/or dilutional coagulopathy later. An initial rapid infusion of 20 ml/kg is appropriate for the hypotensive child and may be repeated. If the child has a head injury, then normal saline (isotonic) should be used for volume replacement to reduce the potential for cerebral edema.
Other plasma substitutes may be used (e.g., dextran 70, hetastarch). Note that dextrans may impair coagulation and interfere with cross-matching: do not exceed 7 ml/kg. Hetastarch does not impair coagulation, and may be used in volumes up to 25 ml/kg. (N.B. The starches have long resident times in the reticuloendothelial system in humans; limited data are available for their use in children.)
Dextrose-containing solutions should not be given (except, very rarely, to treat documented hypoglycemia); hyperglycemia may occur and may increase the severity of neurologic damage (blood glucose >200 mg/dl) should cerebral hypoxia/ischemia occur.
Expanding the blood volume with 5% albumin may be very effective in the immediate treatment of hypovolemic shock, but there is a concern that, if large quantities of albumin are infused, some may “leak” into the lungs and impair pulmonary function later.
Indications for Blood Transfusion
It is seldom possible to measure the volume of blood lost after trauma. Large amounts may be lost from the intravascular volume but remain within hematomas (e.g., after fracture of the femur) or body cavities. Volume replacement must therefore be judged on the basis of the clues listed previously. We recommend that sufficient fluid be replaced to correct clinical signs of hypovolemia and that blood be given in volumes sufficient to maintain hematocrit (Hct) at 30%.
The young child who is showing obvious signs of hypovolemia (pallor, sweating, hypotension) must be assumed to have lost at least 25% of the blood volume. Estimate the weight of the child [for children < 8 years old: 2 × age (yr) + 9 = weight (kg) and for ³ 9 year olds, 3 × age (yr) = weight (kg)] and assume the normal blood volume to be 70 ml/kg; 25% of this total is the initial volume to be replaced rapidly. The situation can then be reassessed. The need for continuous infusion to maintain the BP, or deterioration after an apparently stable period, indicates persistent bleeding.
Children who have lost large volumes of blood require transfusion with whole blood. The trend toward blood component therapy has made it difficult to obtain whole blood. Packed cells resuspended in plasma (preferably recently thawed FFP) may be substituted.
Massive Blood Transfusion
Loss of an amount of blood that would be negligible in an adult (500 ml) may constitute a major loss in a child. Indeed, massive blood transfusions may be required for severely injured children. For example, after thoracoabdominal injury, it may be necessary to replace more than 250% of the estimated blood volume.
Serious problems begin to develop after the rapid infusion of 200% of the estimated blood volume (i.e., transfusion of ~140 ml/kg). These problems include:
- 1.
Hypothermia and accompanying cardiac arrhythmias. Warm all blood and fluids to 40 °C.
- 2.
Coagulation problems
- a.
Thrombocytopenia and impaired platelet function
- i.
Check platelet count after each 50% blood volume replacement.
- ii.
If the platelet count is less than 50,000/mm 3 , administer platelet concentrates (0.1 to 0.3 units/kg).
- i.
- b.
Deficiency of coagulation factors
- i.
Measure prothrombin time (PT) and partial thromboplastin time (PTT)
- ii.
If these are prolonged, give recently thawed FFP (20 ml/kg). (Generally this occurs after loss of 1 to 1.5 blood volumes.)
- i.
- c.
Disseminated intravascular coagulation (DIC).
- i.
Likely if bleeding increases at all sites (i.e., old venipuncture sites).
- ii.
Measure PT, PTT, clot lysis time, fibrinogen, and fibrin split product levels.
- iii.
Prolonged PT and PTT, low fibrinogen level, and presence of fibrin split products suggest DIC.
- iv.
If DIC is suspected, enlist the aid of a hematologist if possible. Treatment must include removal of the cause (i.e., correction of hypovolemic shock), replacement of coagulation factors, and possibly heparinization.
- i.
- a.
- 3.
Acidosis
- a.
Check acid-base status frequently.
- b.
Correct metabolic acidosis with sodium bicarbonate.
- a.
- 4.
Citrate toxicity (due to infusion of citrated blood or plasma)
- a.
May cause more problems in infants and small children than in adults.
- b.
Results in hypotension that persists despite adequate volume replacement. (N.B. Remember that FFP and platelet suspensions contain more citrate per unit volume than whole blood and clinically important hypocalcemia will occur when infusions exceed 1 ml/kg/min FFP.)
- c.
May be diagnosed by measuring the ionized Ca ++ concentration or clinically by observing a prolonged rate-corrected Q-T interval on the ECG. But, in practice, if hypotension appears unresponsive to volume replacement, a therapeutic test using intravenous calcium chloride (10 mg/kg) is justified.
- d.
Correct by administering 10% calcium chloride 10 to 30 mg/kg slowly under ECG control. Frequent small boluses (5 to 10 mg/kg calcium chloride or 15 to 30 mg/kg calcium gluconate) during rapid FFP infusions will prevent serious hypocalcemia.
- a.
- 5.
Serum potassium disturbances: Monitor serum K + levels periodically. Contrary to expectation, hypokalemia may sometimes be found after massive transfusion. However, serious hyperkalemia may also occur, especially in the presence of a low cardiac output, transfusion of old cold blood and the use of a rapid infusion device. The cardiac manifestations of hyperkalemia (peaked T waves, ventricular irritability, ventricular tachycardia) may be treated acutely by slow administration of intravenous calcium chloride 10 to 30 mg/kg, sodium bicarbonate 1 to 2 mmol/kg, hyperventilation, administration of a β-agonist, and, if more severe, with glucose, insulin, and Kayexalate.
- 6.
Posttraumatic pulmonary insufficiency. This is characterized by progressively decreasing pulmonary compliance, impaired gas exchange, and radiographic findings of diffuse infiltrates. The following factors may contribute:
- a.
Excess use of balanced salt solutions and/or albumin
- i.
Give diuretics (furosemide 1 mg/kg) if indicated.
- i.
- b.
Microembolization of the pulmonary vessels by infused particulate matter (platelet or leukocyte clumps)
- i.
Filter all blood given through an IV screen filter (140 μm) filter.
- i.
- c.
Damage to alveolar-capillary membrane
- i.
This results in low-pressure pulmonary edema.
- ii.
Large doses of steroids may help to prevent this.
- i.
- a.
Autotransfusion
Autotransfusion can be life-saving for some trauma patients. Advantages are the ready availability of absolutely compatible warm red cells. In the extreme emergency, autotransfusion can be performed using only a large syringe and an in-line filter in the intravenous line. A collection of freshly shed uncontaminated blood in an accessible body cavity (e.g., the pleural cavity) is the main requirement. Do not use blood from the abdominal cavity if bowel injury is suspected.
Head Injury
Head injury is extremely common during childhood, and it is a cause of very significant mortality and morbidity, much of which might be reduced by early and efficient medical intervention. Children with head injury are less likely than adults to develop a mass lesion but are more likely to develop intracranial hypertension, secondary to diffuse hyperemia and edema. This secondary brain injury, which occurs after the primary trauma, must be minimized if recovery is to be optimized. Early aggressive treatment is essential to ensure cerebral oxygenation, control ICP and CPP, and minimize cerebral edema. The Glasgow coma scale is the most common means of initial assessment.
Glasgow Coma Scale and Pediatric Modifications
If consciousness is significantly depressed (GCS <8), airway obstruction is very common and seriously compromises the prognosis. The first priority of the anesthesiologist must be to ensure an absolutely clear airway, excellent oxygenation, and optimal ventilation. All children with head injury should receive oxygen. If there is any doubt about the child’s ability to maintain the airway and ventilate:
- 1.
Give oxygen and intubate the trachea without delay; use a cuffed oral tube. Suitable drugs should be given to obtund the cardiovascular responses to intubation (see previous discussion). Nasal tubes (and nasogastric tubes) are contraindicated in children with fractures of the base of the skull; perforation of the cribriform plate may occur. Beware of the possibility of cervical spine injury (see SCIWORA later discussion).
- 2.
Apply controlled ventilation to produce normocapnia pending further evaluation of the child’s injuries. Hyperventilation should be avoided because it may compromise cerebral perfusion. PaCO 2 should preferably be checked by arterial blood gas analysis as end-tidal CO 2 may be inaccurate.
- 3.
Continue anesthesia as required, preferably with intravenous agents (e.g., propofol, opioids, and muscle relaxants). Inhalational agents should be limited to < 1 MAC to prevent possible increases in ICP. MAP should be maintained to preserve CPP. Nitrous oxide may increase ICP. Avoid sufentanil, which increases ICP in head-injured patients.
- 4.
Stabilize the hemodynamic state to ensure an optimal CPP. Glucose-free, isotonic fluids (normal saline) should be infused cautiously; excessive fluid therapy contributes to cerebral edema.
| Standard | Score | Pediatric |
|---|---|---|
| Eye opening Spontaneous To speech To pain None | 4 3 2 1 | Spontaneous To speech To pain None |
| Verbal response Oriented Confused Inappropriate words Incomprehensible sounds None | 5 4 3 2 1 | Coos, babbles (age appropriate) Irritable, cries Cries to pain Moans to pain None |
| Motor response Follows commands Localizes to pain Withdraws to pain Abnormal flexion Extensor response None | 6 5 4 3 2 1 | Spontaneous movement Withdraws to touch Withdraws to pain Abnormal flexion Extensor response None |
The use of CT and MRI permits accurate anatomic mapping of traumatic lesions and removes the need for exploratory burr holes. CT or MRI is generally recommended for any child with GCS less than 13 or with vomiting. The characteristic appearance of diffuse cerebral damage on the scan can obviate the need for craniotomy and permit early specific monitoring and therapeutic measures, such as the following:
- 1.
ICP monitoring—most commonly with the use of an extradural bolt connected to an external transducer. This is usually recommended for any child with a GCS less than 8. Once ICP monitoring is established, the CPP can be determined:
CPP = MAP − ICP.
Patients with a CPP between 40 and 70 mm Hg have a better prognosis than those with CPP < 40 mm Hg.
- 2.
Initiate treatment to control ICP and CPP:
- a.
Optimal positioning, 35 ° to 45 ° head up and face centrally forward. (No internal or external jugular lines in children with head injuries.)
- b.
Diuretics—mannitol and/or furosemide
- c.
Hypertonic saline infusions
- d.
Barbiturates (thiopental 2 to 4 mg/kg), which may be more effective in controlling ICP in children than in adults and may also be useful to control seizures.
- e.
Controlled ventilation, preferably adjusted on the basis of measurements of ICP, CPP, and CMRO 2 . Excessive hyperventilation may be detrimental.
- a.
- 3.
Maintenance of optimal CPP (> 40 mm Hg), hemoglobin level, and arterial oxygenation: Glucose-free isotonic or hypertonic fluids should be used for volume expansion. Dopamine may be required to treat hypotension (but see caution in later discussion). Hyperglycemia should be avoided because it may exacerbate secondary brain injury. Fluid therapy must be guided by constant monitoring of physiologic and biochemical variables. Endocrine functions (especially pituitary/hypothalamic) may be disturbed after head injury, which may lead to;
- a.
Diabetes insipidus, with a large urine volume and hypernatremia.
- b.
Inappropriate secretion of antidiuretic hormone (SIADH) with oliguria and hyponatremia.
- c.
Hyperglycemia is common after head injury, secondary to catecholamine release; the value of treating this is controversial. Hypoglycemia may develop later and should be corrected.
- a.
- 4.
Control of seizure activity, as evident clinically or by EEG monitoring.
- 5.
Control body temperature:
- a.
To prevent hyperthermia, which commonly follows brain injury.
- b.
Induced moderate (32.5 °C) hypothermia in children with severe traumatic brain injury does not improve neurologic outcome and may increase mortality.
- a.
Caution: Head injuries do not normally cause shock
When anesthetizing or caring for the child with a head injury, be alert for evidence of other injuries. Do not ascribe signs of hypovolemic shock (i.e., tachycardia, hypotension) to the head injury. If such signs are present, search for bleeding from wounds in the scalp and/or other sites (intraabdominal, intrathoracic, or in the limbs). Be constantly aware that hemorrhage at another site may have been overlooked. Although anesthetizing a child for emergency neurosurgery, monitor the cardiovascular system closely and continue measurements (e.g., abdominal girth) to detect hemorrhage.
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