Intra-Transport Stabilization And Management of the Pediatric Patient

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TRANSPORT MEDICINE

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INTRA-TRANSPORT STABILIZATION AND MANAGEMENT OF THE PEDIATRIC PATIENT Susan E. Day, MD

A critically ill or injured pediatric patient is extremely vulnerable during an interhospital transfer. During the hours following resuscitation and stabilization, the initial problem may recur, the underlying illness may progress, the patient's status may improve, or the patient may suffer complications of therapy. During this period of time, the staff of both the referring hospital and the transport team must anticipate any of these occurrences and be prepared to manage them. An interhospital transfer requires that responsibility for the patient's care be transferred twice: first to the interhospital transport team and then to the receiving hospital staff. Therefore, accurate and complete communication regarding the patient's status is essential at the time the transfer is arranged. The referring staff should initiate the transfer process as soon as it is indicated and have available as much information as possible. This includes a complete set of recent vital signs, any pertinent history and physical examination, and any laboratory results. The first responsibility of the transport team is to obtain sufficient information at the initiation of the transport to ensure that the appropriate personnel, equipment, medications, and vehicle are available to meet the patient's needs. The transport team also should confirm that all foreseeable needs of the patient can be met by the resources available at the receiving hospital, including subspeciality consultants and a bedspace in the appropriate critical care unit. Personnel at the receiving hospital should provide the referring staff with ongoing consultation as needed while the transport team is en route. From the Department of Pediatrics, Section of Critical Care Medicine, Medical College of Wisconsin; and Pediatric Intensive Care Unit, and Transport Program, Children's Hospital of Wisconsin, Milwaukee, Wisconsin

PEDIATRIC CLINICS OF NORTH AMERICA VOLUME 40 • NUMBER 2 • APRIL 1993

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On arrival at the referral hospital, the transport team's next responsibility is to assess the patient's current status and receive updated information from the referral staff. The transport team should attempt to identify significant derangements in gas exchange and circulation and stabilize these as efficiently as possible. The neurologiC status is also assessed, and measures are taken when necessary to protect the central nervous system (CNS) from secondary hypoxic or ischemic injury and to treat seizure activity or increased intracranial pressure. Any metabolic or hematologic disorders that may affect CNS function and oxygen delivery are also investigated and addressed. This evaluation can be initiated by the referring staff by checking frequent vital signs and obtaining a chest radiograph, arterial blood gas, complete blood count, seruII1 electrolytes, blood urea nitrogen, creatinine, glucose, and calcium. When indicated by the patient's presentation and when additional studies will not delay transfer, it also may be appropriate to obtain a blood culture, coagulation studies, liver function tests, spinal fluid studies, cervical spine films, or head CT scan. All information available to the referring staff regarding any procedures performed and all medications and fluids given should be clearly documented. Copies of all imaging studies should be available. It is not the purpose of the transport team to provide definitive, curative care at the referring hospital. The time taken to ensure that the stability achieved by the referral staff and transport team can be maintained during the transfer is time well spent, however. Equipment and medications23 should be prepared to detect and manage recurrent instability, such as hypotension, hypoxemia, seizures, or complications of therapy, such as a pneumothorax or the loss of vascular access or airway. 10, 13, 25 The challenge of interhospital pediatric critical care transport is heightened by the diversity of patients who require this service. Table 1 lists the provisional diagnoses of 2124 patients who were transported to Children's Hospital of Wisconsin by our interhospital transport team and affiliated aeromedical program during the years 1989 through 1991. This list of chief complaints and diagnoses at the time of the initiation of transport illustrates several general features of pediatriC interhospital transport. The range of medical and surgical problems that the transport team encounters is broad. The predominance of respiratory and neurologic complaints is consistent with reports from other pediatric transport programs, however. 2, 4,10,12,16 The prevalence of head injury among children who suffer trauma is common. Pediatric transport programs that transport neonates also encounter complications of prematurity, congenital heart lesions, and other congenital surgical anomalies. Another common feature of pediatric referrals illustrated by this list is the frequency of nonspecific complaints. For instance, the complaint of "respiratory distress" may indicate upper airway obstruction, reactive airway disease, or an alveolar process. It also may represent unidentified congenital heart disease, congestive heart failure, metabolic acidosis, or any number of other systemic problems. The diagnosis of "sepsis" is usually presumptive, based on the presence of cardiovascular collapse, fever, or generalized toxic appearance. The most common diagnosis listed is seizures. The cause of seizure activity may not be apparent at the time of referral and can include trauma, infection, intoxication, hypoglycemia, or electrolyte imbalance. The causes of altered mental status or coma are equally as numerous and difficult to differentiate during initial stabilization and resuscitation. Consequently, the transport team must be prepared to evaluate and begin treatment for all reversible causes of these problems. The detailed discussion of the pathophysiology, evaluation, and management of all of these pediatric and neonatal problems is well beyond the scope

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Table 1. PROVISIONAL DIAGNOSIS OF 2124 PATIENTS TRANSPORTED TO CHILDREN'S HOSPITAL OF WISCONSIN, 1989-1991 Pediatric Transports

RESPIRA TORY "Respiratory distress" Asthma Pneumonia Croup/stridor Apnea Epiglottitis Bronchiolitis Drowning Smoke inhalation Respiratory failure/arrest Aspiration Tracheitis Other

NEUROLOGIC Seizures Meningitis Altered mental status/coma Intracranial hemorrhage Reye syndrome Hypotonia Encephalitis Obstructive hydrocephalus Anoxic brain injury Brain tumor Increased intracranial pressure Other

TRAUMATIC Multiple or unspecified injuries Head injury/skull fracture Burns Abdominal injury Extremity injury Spinal cord injury Chest injury Strangulation/asphyxiation Vertebral fracture Lacerations Facial fracture Child abuse Electrocution

SURGICAL Bowel obstruction/intussusception Foreign body Complications of surgical care Peritonitis Appendicitis Other

Number 529 (24.9%) 106 101 65 51 44 41 35 30 17 14 9 3 13 359 (16.9%) 250 58 19 14 4 3 2 2 2 2 1 2 307 (14.4%) 133 93 44 9 8 5 4 4 2 2 1 1 1 64 (3.0%) 28 17 9 3 2 5

Number CARDIOVASCULAR Cardiac arrest Supraventricular tachycardia Congestive heart failure Other dysrhy1hmias Shock Cardiomyopathy Myocarditis Other

OTHER MEDICAL POisoning "Sepsis" Dehydration Diabetes mellitus Gastrointestinal tract hemorrhage Hemolytic uremic syndrome Viral infections Diarrhea/vomiting Hematologic disorders/neoplasms Kawasaki syndrome Abscess/septic arthritis Gastrointestinal disorders Fever Anaphylaxis/allergy Acute renal failure Hypothermia Other

80 (3.8%) 33 18 10 5 3 3 2 6 339 (15.9%) 80 79 38 25 18 11 10 9 7 6 5 5 4 3 3 3 33

Neonatal Transports

CONGENITAL ANOMALIES Cardiac Gastroi ntesti nal tract Congenital diaphragmatic hernia Central nervous system Airway/respiratory tract Abdominal wall defect Genitourinary system Chromosomal anomaly Multiple or other anomalies

RESPIRATORY Meconium aspiration syndrome Respiratory distress syndrome/ pulmonary hypertension Bronchopulmonary dysplasia Other

OTHER NEONATAL Prematurity Perinatal infection Feeding problems Birth asphyxia Intraventicular hemorrhage Perinatal jaundice Necrotizing enterocolitis Intestinal perforation Other

337 (16%) 140 82 27 24 22 16 6 2 18 73 (3.4%) 32 29 7 5 36 (1.7%) 11 8 5 2 2 2 2 2 2

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of this article and has been well described elsewhere. " 15 The remainder of this article addresses the stabilization and intra transport management of several major categories of pediatric problems: hemodynamic instability, upper airway obstruction, reactive airway disease, seizures, increased intracranial pressure (Iep), artificial airways, chest tubes, patient restraint, and temperature control. THE HEMODYNAMICALLY UNSTABLE CHILD

The management of the child in shock is addressed elsewhere in this issue and usually begins with an evaluation and treatment for hypovolemia. 19, 20 The referring staff or transport team assesses the child's response to one or more boluses of isotonic crystalloid or blood products, depending on the presumed etiology of fluid losses. If the child has little or no clinical response to fluid resuscitation, or if signs of cardiac failure such as cardiomegaly or pulmonary edema are present, then inotropic support should be initiated. Ideally, a central venous pressure would be measured. It may not be practical to place a central venous catheter, however, depending on the capabilities of the referring institution, the degree of instability of the child, and time constraints. Other causes of shock should be ruled out, including dysrhythmias, anaphylaxis, pericardial tamponade, and tension pneumothorax. Table 2 is a guide for mixing vasoactive drug solutions. If an accurate ' patient weight is not available, an approximate weight may be used, and the drug dose should be titrated to effect. At least 50 mL of the drug in solution should be prepared to ensure that the infusion lasts for the duration of the stabilization and transport. The solution should be delivered using a continuous infusion pump capable of delivering a rate as low as 0.1 mLIh, and lasting several hours with battery power. Selection of the appropriate drug depends on the clinical impression of the patient's needs: inotropy, chronotropy, vasoconstriction, or afterload reduction. 20, 28 Multiple continuous infusions can be administered through a 3:1 or 2:1 administration set connected by a stopcock to a T-connector close to the intravascular catheter. The transport team can prepare solutions before arrival at the referring hospital if it is known at the time of dispatch that the patient is receiving continuous infusion medications. The solutions can be running through the intravenous tubing while the team is on the way to the referring hospital and then be ready to administer on arrival. If necessary, the solutions should be started with an initial bolus of 0.5 to 1.0 mL until a positive change is seen in the vital signs, and then the rate can be decreased to the desired dosage. During the first few weeks of life, cardiovascular collapse may be related to a ductus-dependent congenital heart lesion, such as coarctation of the aorta. When such a lesion is highly suspected, it may be appropriate to initiate infusion of prostaglandin E, and to intubate electively because of the high risk of apnea with this drug. The assessment of the hemodynamically unstable patient before and during transfer includes the recording of capillary refill times, mental status, extremity temperature, and skin color. Heart rate, blood pressure (preferably intraarterial), and oxygen saturations should be recorded at least every 5 minutes. Urine output is best monitored with a Foley catheter. Supplemental oxygen should be supplied to all patients in shock, and consideration should be given to elective intubation of patients with marginal hemodynamic status. A resuscitation bag and mask always should be readily available. Arterial blood gases should be checked before leaving the referring hospital to assess acid-base status.

Table 2. VASOACTIVE DRUG INFUSION GUIDE Drug* Formulation, mglmL Drip Slrengtht

Dopamine

Dopamine

Dobutamine Dobutamine Epinephrine Norepinephrine

40.0 mg/mL

40.0 mg/mL

1x 60

lOx 600

12.5 mg/mL 1x 60

DOPA 1 x (ml) 0.07 0.11 0.15 0.19 0.23 0.26 0.30 0.34 0.38 0.45 0.53 0.60 0.68 0.75 0.82 0.90 0.97 1.05 1.13 1.20 1.27 1.35 1.43 1.50 1.69 1.88 2.06 2.25 2.44 2.63 2.81 3.00 3.19 3.38 3.56 3.75 3.94

DOPA lOx (ml) 0.75 1.13 1.50 1.88 2.25 2.63 3.00 3.38 3.75 4.50 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 16.88 18.75 20.63 22.50 24.38 26.25 28.13 30.00 31.88 33.75 35.63 37.50 39.38 41.25 43.13 45.00

12.5 mglml lOx 600

1.0 mg/mL 0.1 x 6

1.0 mg/mL 0.1 x 6

EPI 0.1 x (ml) 0.30 0.45 0.60 0.75 0.90 1.05 1.20 1.35 1.50 1.80 2.10 2.40 2.70 3.00 3.30 3.60 3.90 4.20 4.50 4.80 5.10 5.40 5.70 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00

NOREPI 0.1 x (ml) 0.30 0.45 0.60 0.75 0.90 1.05 1.20 1.35 1.50 1.80 2.10 2.40 2.70 3.00 3.30 3.60 3.90 4.20 4.50 4.80 5.10 5.40 5.70 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 12.75 13.50 14.25 15.00 15.75 16.50 17.25 18.00

lsoprot

Tolazoline

0.2 mg/mL 25.0 mg/mL 0.1 x lOx

6

600

ISO 0.1 x (ml) 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 9.00 10.50 12.00 13.50 15.00 16.50 18.00 19.50 21.00 22.50 24.00 25.50 27.00 28.50 30.00 33.75 37.50 41.25 45.00 48.75

TOl lOx (ml) 1.20 1.80 2.40 3.00 3.60 4.20 4.80 5.40 6.00 7.20 8.40 9.60 10.80 12.00 13.20 14.40 15.60 16.80 18.00 19.20 20.40 21.60 22.80 24.00 27.00 30.00 33.00 36.00 39.00 42.00 45.00 48.00

Nitropr 25.0 mg/mL 1x 60

pge 1

Lidocaine

0.5 mg/mL 20.0 mgJmL lOx 0.1 x

6

600

Desired ~glkglmL

PATIENT WEIGHT 1.00 kg 1.50 kg 2.00 kg 2.50 kg 3.00 kg 3.50 kg 4.00 kg 4.50 kg 5.00 kg 6.00 kg 7.00 kg 8.00 kg 9.00 kg 10.00 kg 11.00 kg 12.00 kg 13.00 kg 14.00 kg 15.00 kg 16.00 kg 17.00 kg 18.00 kg 19.00 kg 20.00 kg 22.50 kg 25.00 kg 27.50 kg 30.00 kg 32.50 kg 35.00 kg 37.50 kg 40.00 kg 42.50 kg 45.00 kg 47.50 kg 50.00 kg 52.50 kg 55.00 kg 57.50 kg 60.00 kg

N

0\ ~

4.13

4.31 4.50

DOBUT 1 x DOBUT lOx (ml) (ml) 0.24 2.40 0.36 3.60 0.48 4.80 0.60 6.00 0.72 7.20 0.84 8.40 0.96 9.60 1.08 10.80 1.20 12.00 14.40 1.44 16.80 1.68 1.92 19.20 2.16 21.60 2.40 24.00 26.40 2.64 2.88 28.80 3.12 31.20 33.60 3.36 3.60 36.00 3.84 38.40 4.08 40.80 43.20 4.32 45.60 4.56 4.80 48.00 5.40 6.00 6.60 7.20 7.80 8.40 9.00 9.60 10.20 10.80 11.40 12.00 12.60 13.20 13.80 14.40

NITROPR 1 x PGE 0.1 x (ml) (ml) 0.12 0.60 0.18 0.90 0.24 1.20 0.30 1.50 0.36 1.80 0.42 2.10 0.48 2.40 0.54 2.70 0.60 3.00 0.72 3.60 0.84 4.20 4.80 0.96 1.08 5.40 6.00 1.20 1.32 6.60 7.20 1.44 7.80 1.56 1.68 8.40 9.00 1.80 1.92 9.60 2.04 10.20 2.16 10.80 2.28 11.40 12.00 2.40 2.70 13.50 15.00 3.00 3.30 16.50 3.60 18.00 19.50 3.90 4.20 21.00 22.50 4.50 4.80 24.00 5.10 25.50 5.40 27.00 5.70 28.50 30.00 6.00 6.30 31.50 33.00 6.60 6.90 34.50 7.20 36.00

LIDO lOx (ml) 1.50 2.25 3.00 3.75 4.50 5.25 6.00 6.75 7.50 9.00 10.50 12.00 13.50 15.00 16.50 18.00 19.50 21.00 22.50 24.00 25.50 27.00 28.50 30.00 33.75 37.50 41.25 45.00 48.75

*Volume of drug to dilute to 50 mL with 5% or 10% dextrose in water to give desired concentration. 1 x : 60 fJ.9/k9/mL _ 1 mUh = 1.0 fJ.g/kg/min. lOx: 600 IJ-g/kg/mL- 1 mUh = 10 fJ.g/kgimin. tDrip strength: 0.1 x : 6 ~g/kg/mL - 1 mLih '= 0.1 fJ.Q/kg/min. DOBUT = dobutamine; DOPA = dopamine; EPI = epinephrine; ISO, ISQPROT = isoproterenol; LIDO = lidocaine; NITROPR sodium nitroprusside; NOREPI = norepinephrine; PGE 1 = prostaglandin E 1; TOl = tolazoline. Courtesy of George M. Hoffman, MD. :0

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The team transporting a hemodynamically unstable patient should have 5% albumin, normal saline, or lactated Ringer's solution prepared for administration. More than one venous catheter should be in place before leaving the referring hospital. Additional inotropic medications, infusion pumps, and administration equipment also should be available.

PATIENTS WITH UPPER AIRWAY OBSTRUCTION

The differential diagnosis of upper airway obstruction includes croup, epiglottitis, tracheitis, foreign body aspiration, and retropharyngeal abscess. The diagnosis usually can be made on the basis of history, overall appearance, and airway radiographs.' The evaluation and management focus on achieving adequate gas exchange. A major decision before transport is whether the patient requires an endotracheal tube (ETT) or other artificial airway. The severity of airway obstruction and possible need for intubation can be assessed by the amount of air movement on auscultation, frequency of aerosolized racemic epinephrine treatments, pulse oximetry, presence of mental status changes, and level of fatigue. The child suspected of having epiglottitis or a critical upper airway obstruction should be taken immediately to the operating room at the referring hospital and undergo intubation by an anesthesiologist, with surgical support in case an emergency tracheostomy is necessary. Cultures of the tracheal secretions, epiglottis, or blood should be obtained at that time. Venous access also can be secured and antibiotics administered. Before transfer, ETT position should be confirmed with a chest radiograph. Restraints and sedation are needed to ensure a safe transfer. Patients who require aerosol therapy more frequently than hourly or who have mental status changes or borderline oxygenation or ventilation should be considered for elective intubation at the referring hospital before transport. The ETT size selected should be at least one size smaller than appropriate for age. A cuffed endotracheal tube should not be placed in the patient with infectious upper airway obstruction. The appropriate size of the ETT can be assessed by auscultating over the trachea while measuring the airway pressure during bag inflation with an in-line manometer. An air leak is heard around the ETT when the airway pressure exceeds the resistance around the tube. Ideally, air leaks should be present between 10 and 20 cm H 2 0 pressure. A tight fitting ETT (i.e., with air leak heard at more than 20 cm H 2 0 pressure) may cause pressure necrosis of the tracheal mucosa, and judicious replacement with the next smaller size tube should be considered. A patient with severe upper airway obstruction may develop pulmonary edema, especially after the obstruction is relieved.l1 This is treated with supplemental oxygen, diuretic therapy, and positive end-expiratory pressure. Intravenous fluids should be given conservatively to maintain euvolemia. Children who have mild airway obstruction should receive supplemental oxygen and have vital signs assessed every 5 to 10 minutes with continuous electrocardiography (ECG) and pulse oximetry monitoring. There should be adequate intravenous access and the ability to provide racemic epinephrine aerosols during transport. The team also should consider having a parent accompany the child to minimize exacerbating the airway obstruction because of agitation. Again, a resuscitation bag and mask and intubation equipment always should be readily available.

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PATIENTS WITH LOWER AIRWAY OBSTRUCTIVE DISEASE

Acute bronchospasm is one of the most common pediatric complaints in emergency departments and a frequent indication for hospital admission. The initial evaluation and management include ECG monitoring, measurement of pulsus paradoxus, pulse oximetry, and supplemental oxygen. 9 A nonrebreathing mask should be used to deliver an Fio2 more than 0.40 when clinically indicated. A chest radiograph reveals hyperinflation and complications such as pneumothorax or pneumomediastinum. A normal or elevated Paco2 on an arterial blood gas from the tachypneic patient indicates impending respiratory failure and a need for prompt bronchodilator therapy. Nebulized ~2 agonist medications are the initial drug of choice. If the patient takes a theophylline preparation, a serum drug concentration should be obtained. A loading dose of theophylline can be given, or the pre-existing serum level can be supplemented to reach the therapeutic range. A corticosteroid bolus should be given to steroid-dependent patients and should be considered for severe refractory bronchospasm in others.27 Ipratropium also may be of benefit. 5 The most important issue for the transport team to resolve is whether the patient has responded to therapy, and whether that improvement can be sustained or advanced during the transfer. Serial arterial blood gases, perhaps from an indwelling arterial catheter, may be necessary. The team should be prepared to deliver frequent doses of aerosolized ~2 agonist medications while monitoring for tachydysrhythmias. Before air transport is performed, air leaks should be ruled out. The goal of fluid management is euvolemia. If the patient does not improve, several interventions need to be considered before transport: continuous nebulized3 , 17 or intravenous8 ~2 agonist and endotracheal intubation with mechanical ventilation. The latter therapy should be considered only after the other options mentioned have failed or when cardiac or respiratory arrest is imminent. Patients with asthma receiving positive pressure ventilation are at high risk for barotrauma and fatal impairment of cardiac outpUt.22 Isotonic or iso-oncotic intravenous fluids should be readily available for intravascular volume expansion. To minimize the risk of barotrauma, the patient should be sedated heavily and may require neuromuscular blockade. A low respiratory rate, low inflating pressure, and long expiratory time are used to safely ventilate the patient with asthma who has undergone intubation. Other medications should be continued while the patient undergoes ventilation and is transported. For children under a year of age, viral bronchiolitis is a common cause for wheezing, especially during the winter months. 26 The etiologic agent in most cases is respiratory syncytial virus. The severity of respiratory illness is variable. Patients are often transferred to tertiary centers specifically for ribavirin therapy or because of underlying diseases that place them at risk for complications. The evaluation of the child with bronchiolitis by the referring staff and transport team includes continuous ECG and pulse oximetry monitoring and frequent vital signs, with attention to work of breathing. Supplemental oxygen should be administered; aerosolized albuterol may have some benefit. 21 Other than administration of bronchodilators, management is primarily supportive. 18 In the moderately or severely affected infant, an arterial or capillary blood gas indicates whether gas exchange is impaired and therefore that intubation and ventilation should be considered before transfer.

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PATIENTS WITH SEIZURES OR INCREASED INTRACRANIAL PRESSURE

Most causes of seizure activity in children are easily identifiable. These include hypoglycemia, hyponatremia, meningitis, drug intoxication, and head trauma. Clinical investigation and treatment should be initiated before leaving the referring hospital. In the case of focal seizures, a head CT scan may be indicated if an intracranial hemorrhage or a mass is suspected. Treatment for bacterial meningitis should be initiated in the absence of a lumbar puncture if increased ICP or hemodynamic or respiratory instability is a concern. It is important for continuity of care that the referring staff and transport team document all changes in neurologic status, the character of all seizures seen, and any evaluation that has already been performed. The initial stabilization for seizures includes supplemental oxygen and the administration of a relatively short-acting anticonvulsant such as diazepam. The patient may then receive a loading dose of a longer-acting anticonvulsant, such as phenytoin or phenobarbital. The loading dose can be started at the referring hospital and continued during transport while the patient is being monitored for respiratory depression or dysrhythmias. Patients who have status epilepticus may require multiple drugs, including phenobarbital, phenytoin, and lorazepam intravenously and paraldehyde rectally.24 Serum anticonvulsant levels obtained on arrival in the emergency department or during treatment assist the transport team's decisions regarding additional dosing. A small dose of sodium thiopental, 1 to 2 mg/kg, may give some short-term seizure control to allow for securing the airway and vascular access while longer-acting agents are infused and the etiology of the seizures is sought. Securing an adequate airway and assuring adequate ventilation and circulation is paramount to preventing secondary brain injury from hypoxemia or ischemia. The management of patients with increased ICP also is directed at preventing secondary injury.14 It is rare during the interhospital phase that the ICP is measured directly. Therefore, it is important for all caretakers to document level of consciousness, response to stimuli, breathing pattern, pupillary responses, and Glasgow Coma Score at frequent intervals during the resuscitation and stabilization. Laboratory results that may be helpful to the transport team include electrolytes, glucose, and serum osmolality. If an osmotic diuretic is to be given, a Foley catheter should be placed to monitor urine output and prevent bladder rupture. Pulse oximetry and arterial or end-tidal CO 2 monitoring are necessary to assess adequacy of gas exchange, especially if hyperventilation is performed. Arterial blood gases should be obtained to correlate with the noninvasive monitors before departure from the referring hospital. If the patient is not hypoglycemic, then an isotonic fluid without glucose should be infused. Fluid can be given at two thirds to three fourths of the calculated maintenance rate if the patient is hemodynamically stable. For a patient who is hemodynamically unstable and requires fluid administration to ensure adequate systemic and cerebral perfusion, intravenous volume should not be restricted. The patient's head should be elevated 30 degrees and positioned in the midline to facilitate venous drainage. Ventilation should be performed with as low a positive end-expiratory pressure as is needed to maintain adequate oxygenation. Intra-arterial blood pressure monitoring is optimal for assessing patients who may undergo volume shifts with osmotic diuresis and may experience myocardial depression from medications administered to lower ICP or treat seizures. For acute changes in pupillary response or abnormal posturing, mannitol

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can be given starting at doses of 0.25 glkgldose. A head CT scan performed at the referring hospital while the team is en route may be helpful in ruling out a lesion that requires surgical intervention. PATIENTS WHO UNDERGO INTUBATION

Patients who have respiratory failure, loss of airway protective reflexes, increased ICP, or other indications for intubation may have had the procedure performed prior to the arrival of the transport team. 6 The team's initial assessment should include checking the tube position by physical examination and chest radiograph and assessing the appropriate size of the ETT by listening for an air leak. Securing the ETT is of paramount importance. Because there is variability in sizes of ETTs used for children, commercially available immobilization devices may have limited use for pediatric patients. Any wet or loose tape should be removed and replaced. The area around the nose or mouth should be dried and prepared with tincture of benzoin. An orotracheal ETT should be placed in a corner of the mouth and secured with a piece of 1-in tape, torn longitudinally in half down two thirds of its length. One leg of the tape is placed across the skin above the upper lip and the other leg around the ETT. The remainder of the tape should be over the cheek on the same side of the mouth as the ETT; two or three pieces of tape can be placed in a similar fashion. Nasotracheal tubes may be secured in a similar fashion. For the awake, orally intubated patient, a bite block may be necessary to prevent tube obstruction. The ETT should not be trimmed before transport. A shortened endotracheal tube may prove to be too short if it needs to be repositioned. The markings on the ETT at its final position at the lips or nares should be recorded. The ETT should be suctioned thoroughly before departure from the referring hospital. Unless the patient undergoes ventilation with a humidifier in the circuit, it is recommended to instill some saline into the ETT approximately every 30 minutes and suction as needed to prevent airway obstruction with dried secretions. At the first sign of worsening pulmonary compliance, the tube position and patency should be verified. An orogastric or nasogastric tube should be placed to limit resistance to ventilation from a distended abdomen. The risk of aspiration is also decreased by removing gastric contents. The gastric tube can be either left to drain or aspirated intermittently. Arterial blood gases should be measured before departure from the referring hospital to assess the adequacy of ventilation and oxygenation. The ventilatory rate, inflating pressure, tidal volume, and positive end-expiratory pressure can be adjusted accordingly. Optimally, an anesthesia bag may be used for manual ventilation so that inflating pressures and positive endexpiratory pressure can be measured and changes in compliance can be assessed by the operator. By and large, it is acceptable to transport pediatric patients on Fio2 1.0 until stabilization can be completed at the receiving intensive care unit and all necessary monitoring devices are in place before weaning is attempted. Table 3 may be used to calculate the duration of oxygen flow available from different sizes of cylinders used during interhospital transports. The patient's need for sedation to prevent extubation during transport should be weighed against the need to assess neurologic status. A short-acting anxiolytic, such as midazolam, or an analgesic, such as morphine or fentanyl, can be used during the period of transport to prevent airway complications.

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Table 3. ESTIMATION OF DURATION OF OXYGEN CYLINDER FLOW Cylinder size

D

E

H

Factor

0.16

0.28

3.14

Number of minutes of oxygen flow remaining = Cylinder pressure x Factor/Liter flow.

The patient who is intubated should be assessed during transport with ECG, pulse oximetry, end-tidal CO 2 monitoring, airway manometry, and vital signs at least every 5 minutes. For changes in vital signs or falls in arterial saturations, the following should be considered and addressed: loss of oxygen flow, obstruction in the oxygen delivery tubing, disconnection of the ventilation system from the patient, ETT obstruction, ETT dislodgment (either into a mainstem bronchus or out of the airway altogether), gastric distention, chest wall rigidity from seizure activity or patient agitation, or a pneumothorax. A 20-gauge angiocatheter attached to a stopcock and a 50-mL syringe should be readily available to aspirate air in the case of a suspected pneumothorax. TUBE THORACOSTOMIES

Patients with chest tubes are challenging to transport for several reasons. Children who have developed a pneumothorax because of poor pulmonary compliance are at risk for recurrent or ongoing air leaks. Inadequately evacuated air leaks may compromise gas exchange and cardiac output, especially during aeromedical transport. The position of the chest tube must be verified by chest radiograph, with all side holes located well within the pleural space. The tubes should be sutured and taped securely to the chest wall. The attached apparatus for providing water seal or suction is cumbersome and can be overturned easily. Some patients may not tolerate having chest tube suction discontinued for the period of transfer. In preparation for moving a patient with a chest tube, a Heimlich valve can be attached directly to the end of the thoracostomy tube, and multiple tubes can be joined by V-connectors to a single valve. The patient's tolerance for having the tubes disconnected from continuous suction is assessed by vital signs and pulse oximetry. Reaccumulation of a pneumothorax is ruled out with a repeat chest radiograph. If necessary, a portable suction machine connected to the distal end of the Heimlich valve provides continuous suction until suction on board the transport vehicle can be used. PATIENT RESTRAINT

Most transported children require some form of restraint to prevent loss of vascular access or artificial airway. No matter how sedated or obtunded the patient, it is wise to use at least wrist restraints, attached to the stretcher by safety pins or tied together behind the patient's back. The patient may be swaddled in blankets as long as intravascular catheters are accessible. Pharmacologic restraint with a short-acting sedative may be appropriate, depending on the patient's hemodynamic stability and the need for neurologic assessment. A small patient who is transported on a stretcher may be ineffectively secured by safety belts across the body. In that case, two belts may be crisscrossed over the abdomen and chest, with a third belt across the legs. An

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infant in an isolette should be restrained to prevent side-to-side movement within the bed. Four-point restraints prevent this lateral movement and still permit access to intravascular catheters and allow observation of the infant's color and chest wall movement. TEMPERATURE CONTROL

Infants and children are at risk for developing hypothermia because of their high ratio of body surface area to body mass. In the emergency department, they are frequently undressed for examination and resuscitation. Some stabilization measures are ineffective if the patient is permitted to become hypothermic. Equipment such as a radiant warmer bed for infants and heating lamps for older patients should be available in the emergency setting to prevent hypothermia from exposure. The patient's body temperature should be rechecked periodically after the initial set of vital signs. The transport team has the responsibility of preventing hypothermia during transfer. The small infant can be maintained in a thermoneutral environment in a temperature-controlled transport isolette. The doors of the isolette should be opened as infrequently as possible. For the older infant or child, some heat losses are prevented by having the transport ambulance warm before the patient is loaded. A cap and Mylar-lined heat-reflecting blankets prevent radiant losses. Chemical heat mattresses may be placed underneath and on top of a patient with ongoing hypothermia. SUMMARY

During the period of interhospital transfer, a critically ill child is at risk from the disease, the therapy, and the transfer itself. This risk can be minimized by good communication between the referring and receiving caretakers, careful evaluation and management, anticipation of complications, and a well-equipped and well-trained transport team providing a level of care as close as possible to that available at the receiving critical care unit. ACKNOWLEDGMENT The author would like to thank Linda Kinney, RN, and Adalberto Torres, Jr, MD, for their assistance in the preparation of this article.

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