Cardiopulmonary resuscitation (CPR)--basic and advanced life support--poses major difficulties in children. Despite the use of CPR, mortality rates for cardiac arrest are 70 to 90% for premature and term newborns and 90 to 97% for infants and children. The mortality rate is almost 50% for respiratory arrest alone. Neurologic outcome is often severely compromised.
About 50 to 65% of children requiring CPR are < 1 yr; of these, most are < 6 mo. About 6% of newborns require resuscitation at delivery (see Table 263-11); the incidence increases significantly if birth weight is < 1500 g.
Causes of cardiac arrest in newborns and children are highly variable; the most common are motor vehicle accidents, drowning, burns, gunshot wounds, poisoning, smoke inhalation, SIDS, airway obstruction and asphyxiation from foreign bodies, respiratory tract or systemic infections, and congenital heart disease. In adults, the cause is almost always secondary to severe diffuse coronary artery disease, most commonly with superimposed malignant ventricular tachyarrhythmia. In children, hypoxemia and airway difficulties are major precipitants, resulting in bradyarrhythmias and asystole, whereas only 10% of arrhythmias are ventricular tachyarrhythmias. Thus, in children, routine, rapid defibrillation is not ordinarily needed because, unlike in adults, malignant ventricular arrhythmias are an unlikely cause.
Weight must be measured or estimated accurately to allow calculation of drug doses, which are determined in milligrams and converted to milliliters based on the drug's concentration. This approach often delays timely intervention and can result in serious errors.
Upper airway anatomy is different in children. The head is large with a small face, mandible, and external nares, and the neck is relatively short. The tongue is large relative to the mouth, and the larynx lies higher in the neck and is angled more anteriorly. The epiglottis is long, and the most narrow portion is below the vocal cords at the cricoid ring, allowing the use of uncuffed endotracheal tubes in children (unlike in adults), thereby minimizing trauma to the sensitive mucosal lining of the airway.
Susceptibility to heat loss is greater in neonates and children than in adults because of a large surface area relative to body mass and less subcutaneous tissue. A neutral external thermal environment is crucial during CPR and may range from 36.5° C (97.7° F) in a newborn to 35° C (95° F) in a child. Hypothermia with core temperature < 35° C increases O2 consumption and cardiac output and adds to overall morbidity. As temperature falls, the protective mechanism of increasing heat production through shivering eventually ceases. Oxygen consumption decreases, and severe bradyarrhythmia leading to asystole may occur within 10 to 15 min of profound hypothermia (< 28° C [< 48° F]).
Cardiac compression rate varies from 80 to 100/min, using two hands, one hand, or two fingers on the sternum depending on the child's size (see Fig. 263-3).
Ventilation rate, although identical to the 1:5 ventilation:compression ratio for two-person adult CPR, varies with the age-determined rate of cardiac compression (see Table 263-12).
Selection of airway is difficult, yet vital. Five sizes of airways, six sizes of masks (cuffed and uncuffed), three sizes of ventilation bags, four sizes of laryngoscope blades, nine sizes of endotracheal tubes, and six sizes of suction catheters are available for children.
The precipitating problem should be treated, if possible, immediately after initial assessment; eg, naloxone should be given to newborns whose mothers have received narcotics in the intrapartum period; septic shock should be aggressively managed in patients with meningococcemia; blood loss should be rapidly treated in patients with multiple trauma; and removal of foreign bodies in choking patients must be considered. Specially trained CPR response teams should be readily available for newborns at delivery and for all other children experiencing cardiopulmonary arrest, both in and out of the hospital. The team should assess the need for additional expertise or transfer to a tertiary care facility.
The Apgar score (see Table 263-13) at 1 and 5 min is used to evaluate the condition and progress of the newborn immediately after birth. Components of the score (eg, color, muscle tone, reflex response to nasal catheter) partly depend on physiologic maturity; the score is significantly affected by maternal therapy and fetal cardiorespiratory and neurologic conditions. A score of 7 to 10 at 5 min is considered normal, 4 to 6, intermediate; and 0 to 3, low. A low Apgar score is not per se an indicator of perinatal asphyxia (see below) but is associated with a very small risk of long-term neurologic dysfunction. Infants with an unduly prolonged (> 10 min) low Apgar score have progressively increasing mortality in the first year of life; those who survive may have cerebral palsy.
With asphyxia, color, respiration, muscle tone, reflex response, and heart rate disappear sequentially (efficient resuscitation leads to an immediate improvement in heart rate, followed by reflex response, color, respiration, and muscle tone). Evidence of intrapartum fetal distress, persistence of an Apgar score of 0 to 3 for > 5 min, an umbilical arterial blood gas pH < 7, and a sustained neonatal neurologic syndrome that includes hypotonia, coma, seizures, and evidence of multiorgan dysfunction reflect perinatal asphyxia. The severity and outcome of posthypoxic-ischemic encephalopathy is best gauged by the Sarnat classification (see Table 263-14) in conjunction with EEG, neuroradiologic imaging, and brain stem auditory and cortical evoked responses.
Initial stabilization of the newborn includes positioning, suctioning, tactile stimulation, and O2 administration (see also Fig. 263-4).
Positioning is best achieved on a preheated overhead warmer in the delivery room after quickly drying the infant and removing wet linen. The infant should be placed supine and the neck supported in the neutral position with a rolled towel under the shoulders.
Suctioning of the mouth, nose, and pharynx should be done before delivery of the thorax, especially in newborns delivered through meconium-stained amniotic fluid. Suctioning is best achieved with appropriately sized large-bore catheters (see Table 263-12) using mechanical suction devices with pressure limits of 100 mm Hg (136 cm H2O). It should be performed intermittently, avoiding deep oropharyngeal suctioning.
Tactile stimulation of the newborn (eg, flicking the soles of the feet, rubbing the back) may be necessary to encourage regular, spontaneous breathing.
O2 administration, when required, should occur at 10 L/min through a face mask attached to a self-inflatable or anesthesia bag or at 5 L/min directly from a source using O2 tubing.
Life support involves sequential assessments and interventions. The airway should be rapidly assessed and stabilized to eliminate obstruction and provide suctioning, ventilation, and oxygenation (see Fig. 263-5).
When foreign body obstruction is observed or strongly suspected, relief may be obtained by first encouraging spontaneous coughing in a child who is breathing adequately. Intervention is necessary only if stridor and respiratory difficulty coexist or loss of consciousness occurs. In an infant, five blows between the shoulder blades using the heel of the hand should be followed by five downward chest thrusts in the same location as chest compressions (see Fig. 263-3). The Heimlich maneuver is reserved for children, but the technique varies with patient size. In conscious victims, five upward abdominal thrusts in the midline just above the navel should be performed using clasped fists with the child standing, sitting, or lying. The lying position is reserved for unconscious victims (see Figs. 263-6 and 263-7).
Positive pressure breathing must be initiated if no respiratory effort is present, with breaths delivered over 1 to 1.5 sec to provide effective ventilation while minimizing ventilatory pressure that may result in gastric distention. Rescue breathing is not recommended for the hospitalized newborn because of the ease with which bag and mask ventilation can be established.
External cardiac compression is started if an absent pulse is found at the base of the umbilical cord (newborn), brachial artery (< 1 yr), or carotid artery (>= 1 yr). An appropriate CPR technique and rate is started over the sternum (see Table 263-12) and continued uninterrupted, except for pauses for ventilation in the unintubated child, until the patient responds or efforts are stopped. The positions for chest compressions are shown in Fig. 263-3. To avoid trauma to the liver, the lower third of the sternum should be used for positioning in premature and term newborns, infants, and children < 8 yr. Chest compressions must be accompanied by rescue breathing and close observation for adequate chest excursion, adequate pulses, pupillary reactions to light, and absence of gastric distention. If gastric distention occurs, a nasogastric tube should be inserted.
If basic life support measures elicit no response, advanced life support must be instituted rapidly.
Airway and mask must be of appropriate size (see Table 263-12).
Bag and mask ventilation requires a good seal between mask and face. Criteria for bag and mask ventilation in newborns include inadequate respiratory activity or apnea, heart rate < 100 beats/min, and central cyanosis despite the use of 100% O2.
An oropharyngeal airway (which should not be used in a conscious patient) should be inserted using a tongue depressor to hold the tongue on the floor of the mouth. If a depressor is not available, the airway should be inverted inside the mouth (using the posterior portion of the curved body as a tongue depressor) and rotated into proper position as it reaches the posterior oropharynx. Oral airways are rarely necessary in newborns except when structural abnormalities, such as a bilateral choanal atresia or Pierre Robin sequence (small jaw with variable facial anomalies), are evident. Cuff masks are recommended for children > 5 yr. Early endotracheal intubation is the technique of choice to improve oxygenation, control the airway, and prevent aspiration.
Endotracheal suctioning with the use of a specially designed aspirator attached to the endotracheal tube is the treatment of choice for depressed newborns delivered through meconium-stained amniotic fluid. The correct size of laryngoscope blade reduces the risk of oropharyngeal trauma. In younger children, a straight blade is generally easier to use than a curved blade, although some centers use both blades. The endotracheal tube (which in the larger adolescent sizes should be cuffed to create a good seal) and the suction catheter should be of appropriate size to carry out direct oropharyngeal suctioning and to fit through the internal diameter of each endotracheal tube. (A complete range of sizes should be immediately available.)
The physician should be skilled in achieving vascular access through various sites, because unusual approaches may sometimes be necessary (eg, after burns or trauma). Although central venous cannulation is theoretically preferable in all age groups, it is difficult to achieve if the operator is inexperienced; two large-bore peripheral catheters are an acceptable alternative. Percutaneous femoral, jugular, or subclavian vein access and saphenous vein cutdown are recommended alternatives. Needle placement in the tibial bone marrow space in children < 6 yr allows safe and effective delivery of blood, colloid, and crystalloid solutions and all CPR drugs, including continuous drug infusions. In the newborn, cannulation of the umbilical vein for emergency vascular access is relatively simple.
After the patient has been intubated, ventilated, and oxygenated, cardiac rhythm should be determined. Pharmacotherapy for arrhythmia is outlined in Ch. 205. Recommended drug doses for pediatric resuscitation are listed in Table 263-15. Epinephrine, atropine, and naloxone remain principal drugs in CPR (when vascular access is inadequate, these drugs can be given through the endotracheal tube). Bretylium is a second-line drug after lidocaine for high-risk ventricular arrhythmias, although sufficient data on efficacy in children are still lacking. The use of sodium bicarbonate and calcium chloride has been deemphasized except in clearly defined circumstances, eg, hyperkalemia, hypocalcemia, hypermagnesemia, Ca channel blocker overdose, and severe, persistent metabolic acidosis despite adequate ventilation.
It is imperative to search for and treat underlying disorders that precipitate cardiopulmonary arrest in children. Treatment may include volume replacement with normal saline, colloid, crystalloids, or blood (eg, for trauma or burns). Fluid therapy, however, is difficult for those unaccustomed to pediatric CPR because children have a smaller blood volume, and appropriate amounts must be given cautiously to avoid fluid overload.
Defibrillation is infrequently required because underlying ventricular fibrillation is rare and should be documented before countershock. When defibrillation is used, an appropriate paddle size must be determined: newborns and infants (0 to 12 mo) need pediatric paddles; preschoolers, children, and adolescents should have adult paddles. An appropriate dose of shock should be delivered. However, many defibrillators commonly used for pediatric CPR are standardized with large increments in the energy settings, and it is impossible to adjust the shock accurately based on body weight. Thus, defibrillators should be evaluated for the number and range of energy settings, and equipment upgrades should be made as appropriate.
Cardioversion, used in the treatment of symptomatic rapid supraventricular and ventricular rhythms, is very difficult in the newborn and young child because the energy dose is usually 1/2 to 1/10 the usual adult dose (see Table 263-12). It is probably best to start at the lowest recommended dose, with stepwise increases implemented until the desired effect is attained.
After successful CPR, care is complex and often must address the pathophysiology of multiorgan dysfunction. It is important to assess body temperature and maintain a neutral thermal environment, to monitor urine output with an indwelling urinary catheter, and to insert a nasogastric tube (particularly if the patient is intubated). Evaluation of neurologic function with the modified Glasgow Coma Scale (see Table 263-2), maintenance of metabolic homeostasis, management of cardiovascular stability, and ongoing treatment of the precipitating condition are prime concerns and are best carried out in a tertiary care facility.
Heart rate assessment is mandatory. Bradycardia in a distressed child is a sign of impending cardiac arrest. Newborns, infants, and young children tend to develop bradycardia with hypoxemia, whereas older children tend initially to have tachycardia. In newborns with a heart rate < 80/min that is not rising, cardiac compression is recommended (see Fig. 263-5), which is a major difference from adult resuscitation. Tachyarrhythmias may similarly require intervention, particularly if evidence of hypoperfusion, heart failure, or CNS changes are present. Synchronized cardioversion or drug therapy may be necessary to stabilize the patient.
BP evaluation in very sick children varies significantly. BP should be measured with an appropriate-sized cuff (see Screening in Ch. 256), but direct invasive arterial BP monitoring is mandatory in severely compromised children. For children > 2 yr, the lower level of normal systolic BP can be estimated as 70 plus twice the age in years; eg, at 6 yr it should be > 82 mm Hg. Normal systolic BP at the 50th percentile is 90 plus twice the age in years; eg, at 6 yr it should be 102 mm Hg. A drop in systolic BP of >= 10 mm Hg in any child, or a systolic BP < 50 mm Hg in children < 12 yr or < 80 mm Hg in children aged 12 to 16 yr, is likely to represent serious hypotension requiring therapy. Even higher BP may represent hypotension if symptoms and signs of shock are present. Establishing an absolute lower limit of BP for each age group is difficult; evidence of hypoperfusion (ie, quality of distal pulses, urine output, level of consciousness, skin temperature) is critically important in evaluating the consequences of any level of BP. A capillary filling deficit > 3 sec has limited use in the assessment of circulatory dysfunction in ill or injured children.
Hypoperfusion evaluation is recommended. Hypoperfusion may result from instability of heart rate (bradyarrhythmia or tachyarrhythmia) or BP. Hypoperfusion is suggested by low urine output (< 1 mL/kg/h); renal output in the absence of renal disease should be 1 to 2 mL/kg/h. Hypoperfusion can be treated by volume expansion or by continuous infusion of pressor drugs (eg, epinephrine, dopamine, dobutamine).
The standardized protocol detailed in Tables 263-12 and 263-15 covers all ages, from the premature newborn to the 16-yr-old. For patients > 16 yr of age, adult advanced cardiac life support protocols should be used. The protocol is designed to standardize equipment and streamline resuscitation maneuvers during an arrest and to standardize equipment on all CPR carts. In the approach to airway management, for example, in a 5-yr-old, the recommended procedure involves a ventilation rate of 20 breaths/min (25 breaths/min for a head injury); a compression rate of 100/min (one-hand technique) resulting in a compression; ventilation ratio of 5:1; a size 7 airway; a size 3 dome cuff (Laerdal) mask with a child Laerdal 500-mL ventilation bag for bag and mask ventilation; a size 2 straight or curved blade for laryngoscopy; a 5-mm tracheal tube; an adult tonsil suction for direct oropharyngeal suctioning; and a size 10 French catheter passed through the endotracheal tube to suction the lower airway. Common sense must be used; eg, an appropriate-sized endotracheal tube should be replaced with a larger one (once the patient is stabilized) if a leak is evidenced by audible exhalation of gas at the glottis.
After the airway is stabilized, the rapid administration of emergency cardiac drugs is vital. Dosages should be rounded down; eg, for a 2 1/2-yr-old, dosages should be the same as for a 2-yr-old, with stepwise increments as needed but not exceeding those for a 3-yr-old. After the patient is stabilized, drug dose must be individualized as necessary. Conservative fluid management can be crucial in a patient with cerebral edema; more concentrated infusions may be necessary, but these can be recalculated once the emergency is over.
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