Performance of cardiopulmonary resuscitation in infants and children





Pearls





  • There are four distinct phases of cardiac arrest and cardiopulmonary resuscitation (CPR): prearrest, no-flow (untreated cardiac arrest), low-flow (CPR), and postarrest.



  • The most common precipitating event for cardiac arrests in children is respiratory insufficiency; restoration of adequate ventilation and oxygenation remain a high priority.



  • High-quality CPR (i.e., push hard, push fast, allow full chest recoil, minimize interruptions in chest compressions) improves cardiac arrest outcomes.



  • Real-time monitoring and feedback combined with reflective debriefings of team performance improves CPR quality and survival outcomes.



  • Attention to meticulous postresuscitation care—specifically, avoidance of hypotension and fever—improves survival outcomes.



  • Physiology-directed CPR, in which CPR is titrated to a patient’s physiologic response, is a promising technique to save more children’s lives from cardiac arrest.



Pediatric cardiac arrest is not a rare event. More than 20,000 children are treated with cardiopulmonary resuscitation (CPR) for a cardiac arrest in the United States annually. In the past, survival outcomes were dismal, and many surviving children had severe neurologic sequelae. With advances in resuscitation science, survival from pediatric cardiac arrest has improved substantially since the 1990s. This chapter focuses on pediatric cardiac arrest, CPR, and therapeutic interventions that impact clinical outcomes. Controversies related to pediatric cardiac arrest management are also discussed.


Four phases of cardiac arrest


The four distinct phases of cardiac arrest and CPR interventions are (1) prearrest, (2) “no-flow” (untreated cardiac arrest), (3) “low-flow” (CPR), and (4) postarrest. Interventions to improve the outcome of pediatric cardiac arrest should optimize therapies targeted to the time and phase of CPR, as suggested in Box 39.1 and Table 39.1 .



• BOX 39.1

Phases of Cardiac Arrest and Targeted Interventions


Prearrest phase: Protect





  • Optimize community education regarding child safety



  • Optimize patient monitoring



  • Prioritize interventions to prevent progression to cardiac arrest



  • Early recognition and activation of medical emergency response teams



Arrest (no-flow): Preserve





  • Minimize interval to BLS and ACLS phase



  • Organized 911/code blue response system



  • Preserve cardiac and cerebral substrate



  • Minimize interval to defibrillation, when indicated



Low-flow (CPR): Resuscitate





  • High-quality CPR



  • Consider adjuncts to improve organ perfusion during CPR



  • Consider E-CPR if standard CPR not promptly successful



Postarrest: Regenerate


Short term





  • Monitor for and aggressively prevent:




    • Hypotension



    • Fever




  • Monitor for seizures



  • Avoid extremes of:




    • Oxygenation



    • Ventilation



    • Glucose




  • Continue to address underlying arrest etiology to prevent recurrent arrest



Long term





  • Early intervention with occupational and physical therapy



ACLS , Advanced cardiac life support; BLS , basic life support; CPR , cardiopulmonary resuscitation; E-CPR , extracorporeal membrane oxygenation cardiopulmonary resuscitation.



TABLE 39.1

2015 Cardiopulmonary Resuscitation Quality Targets

























Metric Evidence-Based Target
Depth: Infants/children PUSH HARD
At least one-third the anteroposterior diameter of the chest (≈4 cm in infants and ≈5 cm in children)
Depth: Adolescents a PUSH HARD
At least 5 cm but no more than 6 cm
Rate PUSH FAST
100–120 compressions/min
Chest compression fraction Minimize interruptions
Compressions provided for at least 80% of the arrest duration
Ventilation rate Avoid excessive ventilation
10 breaths/min
Chest recoil FULL chest recoil between all compressions

a Evidence of pubertal development.



Prearrest


The prearrest phase refers to relevant preexisting conditions of the child (e.g., respiratory insufficiency/failure, sepsis, pulmonary hypertension, neurologic disability) and the events that precipitated cardiac arrest (e.g., respiratory decompensation, progressive hypotension and shock, pulmonary hypertensive crisis, drug overdose). Because pediatric patients usually exhibit changes in their physiologic status in the hours leading up to their arrest event, interventions during the prearrest phase should focus on identifying children at risk for arrest, with special attention to early recognition and treatment of respiratory failure and shock. Rapid response teams or medical emergency teams (METs) are in-hospital emergency teams designed specifically for this purpose. While the composition and operating characteristics of these teams vary widely, their existence has become almost universal across pediatric institutions. Implementation of pediatric METs has been successful in that they have been temporally associated with decreased cardiac arrest frequency and mortality. , Although METs cannot identify all children at risk for cardiac arrest, it seems reasonable to assume that transferring critically ill children to an intensive care unit (ICU) early in their disease progression for better monitoring and more aggressive interventions would improve clinical outcome. Supporting this contention, late transfers to the ICU (e.g., unrecognized situational awareness failure events [UNSAFE]) are associated with a higher risk of in-hospital mortality. ,


No-flow/low-flow


To improve outcomes from pediatric cardiac arrest, it is imperative to shorten the no-flow phase of untreated cardiac arrest. To that end, it is important to monitor high-risk patients to facilitate early recognition of the cardiac arrest and initiate basic and advanced life support. Effective CPR optimizes coronary perfusion pressure (CoPP) and cardiac output to support vital organ viability during the low-flow phase. Important tenets of basic life support are: PUSH HARD, , PUSH FAST, allow full chest recoil between compressions, and minimize interruptions in chest compressions. For ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT), rapid rhythm identification and prompt defibrillation are vital for successful resuscitation. , For all cardiac arrests, it is vital to provide adequate myocardial perfusion, to restore myocardial oxygen delivery, and to assess and reverse the underlying arrest etiology. ,


Postarrest


Most deaths in children receiving CPR in the hospital occur after initially successful resuscitation. Thus, the immediate postarrest period should be considered a critical time of ongoing intervention. Patients remain at risk for ventricular arrhythmias and critical organ reperfusion injuries. Interventions during the immediate postarrest stage should focus on minimizing secondary injury. Current evidence-based goals include the following: (1) avoid hypotension (i.e., <5th percentile systolic blood pressure for age), , (2) avoid fever by proactively providing targeted temperature management, and (3) recognize and promptly treat seizures. , This postarrest phase may have the greatest potential for innovative advances to improve functional outcomes and facilitate reintegration of the patient back into society.


The specific phase of resuscitation dictates the focus of care. Interventions that improve outcome during one phase may be deleterious during another. For instance, the administration of vasopressors during the low-flow phase of cardiac arrest raises systemic vascular resistance with the goal of increasing CoPP and the probability of event survival (return of spontaneous circulation [ROSC]). The persistence of this vasoconstriction into the postarrest phase may worsen myocardial strain and dysfunction and negatively impact cerebral perfusion. Current understanding of the physiology of cardiac arrest and recovery allows us to only crudely manipulate blood pressure, oxygen delivery and consumption, body temperature, and other physiologic parameters in our attempts to optimize outcome. Future strategies likely will take advantage of increasing knowledge of mitochondrial bioenergetics, cellular metabolism, and cellular markers of injury and recovery.


Epidemiology of pediatric cardiac arrest


The true incidence of pediatric cardiac arrest is difficult to determine owing to inconsistencies in reporting. However, the best data suggest that over 20,000 American children receive CPR each year (≈15,000 in hospital and ≈7000 out of hospital). Owing in part to the widespread implementation of rapid response systems in most children’s hospitals, more than 95% of in-hospital CPR events in the United States occur in ICUs. Despite improvements in survival over the past 20 years—survival-to-discharge rates now approach or exceed 40% after in-hospital cardiac arrest (IHCA) in most contemporary series—most children receiving CPR still die before discharge, and many survivors sustain neurologic injury as a result of their cardiac arrest. As a specific example, in a recent study by the National Institute of Child Health and Human Development–funded Collaborative Pediatric Critical Care Research Network (CPCCRN), nearly 30% of pediatric survivors of cardiac arrest suffered a significant decline in functional neurologic status. In short, pediatric cardiac arrest is an important public health problem.


Factors that influence outcome from pediatric cardiac arrest include (1) the preexisting condition of the child, (2) the initial electrocardiographic rhythm detected, (3) the duration of no-flow time (the time during an arrest when there is no spontaneous circulation or provision of CPR), and (4) the quality of the life-supporting therapies provided during and after the resuscitation. With this knowledge, it is no surprise that pediatric out-of-hospital cardiac arrests (OHCAs) have worse outcomes than IHCAs. As many of these out-of-hospital events are not witnessed and bystander CPR is not common (≈30% to 40% of children receive bystander CPR), the duration of no-flow time can be prolonged. As a result, less than 25% of these children survive their initial event , as compared with more than 80% of children who receive CPR while in an ICU. These findings are especially troublesome given that bystander CPR more than doubles patient survival rates and points to public health and community outreach interventions as means of improving outcomes.


Pediatric cardiac arrest characteristics differ from those observed in adults in several ways. Adult cardiac arrests in and out of the hospital are likely to be associated with coronary artery disease and therefore frequently have shockable rhythms, whereas pediatric cardiac arrests are usually secondary to respiratory failure or shock and less than 15% have an initial shockable rhythm. , , Despite shockable rhythms being more favorable for survival, more children will survive their cardiac arrest relative to adults. These superior outcomes in children are partly driven by higher survival rates among children with asystole or pulseless electrical activity (PEA) compared with adults (24% vs. 11%). Additionally, CPR is recommended for children with bradycardia with poor perfusion, a common predecessor to pulseless cardiac arrest. Children who receive CPR for bradycardia with poor perfusion have greater chances of survival than those with a pulseless initial CPR rhythm. Importantly, observational studies of in-hospital cardiac arrest have consistently identified higher survival rates in infants as compared with older children.


Optimizing blood flow during cardiopulmonary resuscitation


When the heart arrests, the provision of high-quality CPR is the only source of blood flow to organs. A primary goal of CPR is the maximization of myocardial blood flow to facilitate ROSC. The primary driver of myocardial blood flow is CoPP, mathematically defined by the following equation:


CoPP = Aortic Pressure – Right Atrial Pressure


Myocardial blood flow improves as the gradient between aortic and right atrial pressures increases. During the downward compression phase, aortic pressure rises at the same time as right atrial pressure with little change in CoPP. However, during the decompression phase of chest compressions, the right atrial pressure falls faster and lower than the aortic pressure, which generates a pressure gradient that perfuses the heart with oxygenated blood during this artificial period of “diastole” ( Fig. 39.1 ). Several human and animal studies in both VF and asphyxial models have demonstrated the importance of achieving and maintaining CoPP thresholds to the attainment of short-term survival (i.e., ROSC). , Based on the preceding equation, CoPP can be improved by strategies that increase the pressure gradient between the aorta and right atrium. This is principally accomplished by the provision of vasopressors during CPR to increase systemic vascular resistance and aortic diastolic pressure. Other interventions can target right atrial pressure by augmenting negative intrathoracic pressure—these include the impedance threshold device (ITD) and active compression-decompression device (ACD). The ITD is a small, disposable valve that can be connected directly to the tracheal tube or facemask to augment negative intrathoracic pressure during the inspiratory phase of spontaneous breathing and the decompression phase of CPR by impeding airflow into the lungs. The ACD is a handheld device that is fixed to the anterior chest of the patient by means of suction and is used to apply active decompression forces during the release phase of chest compressions. By actively generating negative intrathoracic pressure during the relaxation phase, cardiac preload is augmented, potentially increasing the cardiac output generated with CPR. While neither device has a clear survival benefit when applied broadly to all patients, animal and adult studies have demonstrated that the ITD and ACD, either alone or in combination, do improve organ perfusion pressures during CPR.




• Fig. 39.1


Hemodynamics during cardiopulmonary resuscitation. Depiction of the hemodynamic response to high-quality chest compressions during pediatric cardiac arrest. Yellow line, Aortic pressure; blue line, right atrial pressure; and black line, coronary perfusion pressure, depicted as the mathematical difference between aortic and right atrial pressure. During the compression phase (systole), right aortic and right atrial pressure rise simultaneously, generating negligible coronary perfusion pressure (a negative value in this example) and likely minimal myocardial blood flow. During the relaxation phase (diastole), aortic pressure exceeds right atrial pressure, allowing for the generation of coronary perfusion pressure and myocardial blood flow. The dashed line at 20 mm Hg represents coronary perfusion pressure threshold associated with improved outcomes in animal and adult human literature.


Pediatric cardiopulmonary resuscitation targets


Chest compression depth


Pediatric chest compression depth recommendations are largely based on expert clinical consensus using data extrapolated from animal, adult, and limited pediatric studies. Supported by two computer-automated tomography studies suggesting that depths of one-half anteroposterior (AP) chest depth are unattainable in most children, , the most recent change to the pediatric depth recommendation occurred in 2015 when the American Heart Association (AHA) Guidelines , recommended a compression depth of “at least one-third AP chest depth” rather than “one-third to one-half.” This subtle change acknowledged the potential difficulty (or even potential harm) of trying to provide chest compressions to one-half AP depth. , These recommendations correspond to approximately 4 cm in infants and 5 cm in children. Once children reach puberty, the adult CPR depth of “at least 5 cm, but no more than 6 cm” is recommended. Again, an upper limit is placed to acknowledge the potential harm of compressions that are too deep. Future studies that collect data from pediatric patients and that associate quantitatively measured CPR mechanics with physiologic measurements and clinical outcomes (e.g., arterial blood pressure, end-tidal carbon dioxide [E tco 2 ], ROSC, survival) are needed.


Chest compression rate


Over the last 20 years, there have been minimal changes to the recommended chest compression rate, which has hovered around 100 per minute for adults, children, and infants. These recommendations were initially based primarily on animal models of cardiac arrest showing improved hemodynamic measures and short-term survival outcomes when rates were increased from 60 to greater than 100 per minute. The most recent refinement to the chest compression rate recommendation occurred in 2015, at which time an upper rate limit (120/minute) was added. , This change acknowledged animal work dating back to the 1980s establishing that higher rates can have a detrimental effect on stroke volume/cardiac output as a result of shorter diastolic filling times, but was also supported by large clinical studies of adult OHCA from the Resuscitation Outcomes Consortium funded by the National Institutes of Health. , Importantly, the guidelines acknowledge that “insufficient data were available for a systematic review of chest compression rate in children” and thereby deferred to the adult guidelines of 100 to 120 chest compressions per minute.


Chest compression fraction/minimizing interruptions


The avoidance of unnecessary interruptions in chest compressions and minimization of the duration of necessary interruptions remain central tenets of high-quality CPR. Laboratory studies have shown that CoPP falls during chest compression interruptions and requires multiple compressions to return to the preinterruption baseline. Recent data in pediatric IHCA suggest that these harmful hemodynamic effects can be attenuated by limiting the frequency and duration of interruptions. Current guidelines call for a goal of maintaining a chest compression fraction (CCF)—the percentage of time during a CPR event spent actually delivering compressions—of more than 80%. However, high-functioning resuscitation teams have reported mean CCFs more than 90%. Recent adult studies have revealed counterintuitive data regarding the relationship between CCF and outcome, but interpretation of these is difficult due to their observational nature. ,


Duty cycle


Duty cycle (DC), the percentage of time spent during the downstroke of a chest compression, remains a relatively understudied aspect of CPR quality. The 2002 version of the Pediatric Advanced Life Support (PALS) Guidelines recommended that rescuers provide compressions with “approximately equal compression and relaxation phases (DC = 50%).” This approximation was based on the argument that it is difficult for the rescuer to judge or manipulate the DC during compressions when they are provided at rates exceeding 100 per minute. However, there are substantial amounts of preclinical data suggesting that a briefer, more “high-impact” compression phase improves organ blood flow. In a recent single-center clinical study of pediatric in-hospital CPR, the mean DC for events was 40%, with only 5% of events having a DC compliant with guideline recommendations. Unfortunately, an optimal DC to improve outcomes could not be established, highlighting the need for further study of this element of CPR quality.


Airway and breathing management during cardiopulmonary resuscitation


It is estimated that even excellent CPR provides only about 25% of normal cardiac output and pulmonary blood flow. As such, less minute ventilation may be necessary for adequate gas exchange (i.e., to match ventilation and perfusion). Moreover, animal and adult data indicate that a rapid rate of assisted ventilation (overventilation from exuberant rescue breathing) during CPR is common and may compromise venous return and cardiac output by increasing intrathoracic pressure. , These hemodynamic effects are compounded when considering the deleterious effects of interruptions in CPR to provide airway management and rescue breathing. Cumulatively, these physiologic observations provide the justification for the provision of a relatively low ventilation rate during adult and pediatric resuscitation.


Although overventilation is problematic, because most pediatric arrests are asphyxial in nature, the provision of adequate ventilation is still important. The difference between arrhythmogenic and asphyxial arrests lies in the physiology. In animal models of sudden VF cardiac arrest, acceptable partial pressure of arterial oxygen (Pa o 2 ) and partial pressure of arterial carbon dioxide (Pa co 2 ) can persist for 4 to 8 minutes during chest compressions without rescue breathing. This is in part because arterial and alveolar oxygen and carbon dioxide concentrations at the onset of the arrest do not vary much from the prearrest state. As a result, the lungs act as a reservoir of oxygen during CPR, and adequate oxygenation and ventilation can continue without rescue breathing. However, when an arrest occurs secondary to a respiratory etiology, there is no pulmonary reservoir of oxygen, and CPR circulates hypoxemic, hypercarbic blood, perpetuating organ hypoxia and acidemia. Therefore, even at the onset of resuscitation, arterial hypoxemia and acidemia can be substantial. In this circumstance, rescue breathing with controlled ventilation can be lifesaving. In fact, whereas hands-only CPR without rescue breathing is a validated method of CPR for adult OHCA, children fare worse when bystander CPR does not include the provision of rescue breaths, especially if they have a noncardiac OHCA etiology. , ,


Evidence has demonstrated that a compression/ventilation ratio of 15:2 delivers the same minute ventilation and increases the number of delivered chest compressions by 48% compared with CPR at a compression/ventilation ratio of 5:1 in a simulated pediatric arrest model. , This is important because when chest compressions cease, the aortic pressure falls rapidly and coronary perfusion pressure decreases. , Increasing the ratio of compressions to ventilations minimizes these interruptions, optimizing myocardial blood flow. These findings are, in part, the reason that the 2015 AHA Guidelines recommend a pediatric compression/ventilation ratio of 15:2. In reality, more work is necessary to determine ideal ranges of ventilation ratios during CPR for children. The best ratio of compressions to ventilations in pediatric patients likely depends on compression rate, tidal volume, blood flow generated by compressions, the time that compressions are interrupted to perform ventilations, and the patient’s underlying physiology. We believe that ventilation strategies that are titrated to individual patient characteristics and physiology warrant investigation. A discussion of airway management and further discussion of ventilation rates during pediatric cardiac arrest follow in the Controversies section.


Physiologic targets


A 2013 CPR Quality Consensus Statement released by the AHA and the 2015 PALS Guidelines recommend physiologic monitoring during CPR with invasive hemodynamics or exhaled E tco 2 . This recommendation was based on decades of experimental and clinical evidence supporting the physiologic response to CPR as a key determinant of outcome. In this updated section, we provide evidence for the use of physiologic targets during CPR.


Arterial blood pressure


In preclinical models of pediatric IHCA, titration of vasopressor administration to CoPP and adjustment of compression depth to systolic blood pressure results in higher rates of survival and improved neurologic outcomes. , , , While CoPP monitoring requires simultaneous measurement of diastolic blood pressure (DBP) and central venous pressure, DBP alone is a more clinically feasible surrogate marker of CPR quality. , In a large multicenter prospective trial conducted in the CPCCRN, a DBP of 25 mm Hg or higher in infants younger than 1 year and 30 mm Hg or higher in older children was associated with improved survival to hospital discharge and survival with favorable neurologic outcome among children with an ICU arrest.


End-tidal carbon dioxide


E tco 2 reflects pulmonary blood flow; thus, it is a marker of cardiac output. There are three main themes regarding E tco 2 use during CPR: (1) low values (<10 mm Hg) are rarely associated with successful resuscitation, (2) E tco 2 values are generally higher among patients who achieve ROSC, and (3) an abrupt rise in E tco 2 can be used to detect underlying ROSC during CPR. , Similar to hemodynamic-directed CPR described earlier, recent animal work in a neonatal model of cardiac arrest has demonstrated that E tco 2 -guided chest compressions are associated with improved rates of ROSC compared with standard CPR. , In a large multicenter prospective pediatric trial, there was no association between E tco 2 and survival, highlighting the need for further pediatric study to establish an E tco 2 target to which CPR could be adjusted. Irrespective of a specific target to guide CPR, E tco 2 remains a useful device for confirmation of invasive airway placement as long as the CPR is sufficient to provide some amount of pulmonary blood flow.


Despite being recommended by the AHA, providers rarely use physiology to guide the resuscitation effort. However, in a propensity-matched cohort, the use of physiologic monitoring was associated with a higher likelihood of ROSC, indicating that more widespread use may be one method to improve pediatric cardiac arrest outcomes.


Medications used to treat cardiac arrest


Although animal studies have indicated that epinephrine can improve initial resuscitation success after both asphyxial and VF cardiac arrests, no single medication has been shown to improve survival outcome from pediatric cardiac arrest. A variety of medications are used during pediatric resuscitation attempts, including vasopressors (epinephrine or vasopressin), antiarrhythmics (amiodarone or lidocaine), and other drugs, such as calcium and sodium bicarbonate.


Vasopressors


Epinephrine


Epinephrine (adrenaline) is an endogenous catecholamine with potent α- and β-adrenergic stimulating properties. The α-adrenergic action (vasoconstriction) increases systemic and pulmonary vascular resistance. The β-adrenergic effect increases myocardial contractility and heart rate. Epinephrine (recommended dose of 0.01 mg/kg) primarily helps achieve ROSC by increasing systemic vascular resistance, which leads to a higher DBP and CoPP. A recent adult randomized controlled trial has suggested no benefit to epinephrine administration during OHCA resuscitation, though it was more than 20 minutes (median) after the emergency call. , In contrast, delayed administration of epinephrine has been associated with worse outcomes in a recent large in-hospital pediatric registry study of patients with nonshockable rhythms, suggesting that, when needed, early administration is better. , Therefore, the 2015 PALS Guidelines continued to recommend epinephrine as a reasonable therapy during CPR. High-dose epinephrine (0.1 mg/kg) is not recommended due to its use being associated with higher mortality in a randomized pediatric cardiac arrest trial. In light of clinical pediatric IHCA data that attainment of adequate DBP during CPR is associated with survival, it seems reasonable to use epinephrine when needed to attain adequate DBP during CPR.


Vasopressin


Vasopressin is a long-acting endogenous hormone that acts to mediate systemic vasoconstriction (V1 receptor) and reabsorption of water in the renal tubule (V2 receptor). The vasoconstriction is most intense in the skeletal muscle and skin vascular beds. Unlike epinephrine, vasopressin does not cause significant pulmonary vasoconstriction. The 2015 Advanced Cardiac Life Support (ACLS) Guidelines removed the use of vasopressin owing to a lack of survival advantage over epinephrine alone. , Owing to limited pediatric data and an association with lower rates of ROSC in an in-hospital Get With The Guidelines–Resuscitation (GWTG-R) registry study, routine vasopressin use is also not recommended during cardiac arrest in children. Experts will still consider administration in select resuscitation circumstances in which adrenergic receptor stimulation may be detrimental (e.g., pulmonary hypertension, arrhythmogenic states) or ineffective (e.g., sepsis with catecholamine-refractory shock).


Antiarrhythmics


Amiodarone versus lidocaine


The 2005 and 2010 PALS Guidelines recommended amiodarone over lidocaine for shock-refractory VF/pVT based on pediatric case series and adult data. Supported by a 2014 pediatric GWTG-R study that demonstrated higher rates of ROSC with lidocaine compared with amiodarone, the 2015 PALS Guidelines removed the preference for amiodarone and simply stated that either amiodarone or lidocaine was an appropriate pharmacologic choice for shock-refractory VF or pVT. Publication of the adult out-of-hospital ALPS study (Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Arrest) prompted a re-review of this topic for the 2018 PALS update. , While this adult study demonstrated no benefit of either antiarrhythmic compared with placebo, given the differences between pediatric and adult cardiac arrest, the pediatric recommendation remained unchanged (i.e., either amiodarone or lidocaine is reasonable for shock-refractory VF/pVT).


Other medications


Calcium


In the absence of a documented clinical indication (e.g., hypocalcemia, calcium channel blocker overdose, hypermagnesemia, or hyperkalemia), administration of calcium does not improve outcome from cardiac arrest. To the contrary, three observational pediatric studies have associated routine calcium administration with decreased survival rates or worse neurologic outcomes.


Sodium bicarbonate


Similar to calcium, routine use of sodium bicarbonate is also not recommended. The 2010 PALS Guidelines state that sodium bicarbonate can be administered in select circumstances (e.g., sodium channel blocker overdose, hyperkalemia, hypermagnesemia). While there are no randomized controlled studies in children examining the use of sodium bicarbonate for management of pediatric cardiac arrest, two multicenter retrospective in-hospital pediatric studies have found that sodium bicarbonate administered during cardiac arrest is associated with decreased survival. ,


Postarrest interventions


The postarrest phase should focus on limiting secondary injury. Management priorities include (1) anticipation of and prevention of hyperthermia (targeted temperature management), (2) avoidance of hypotension, (3) avoidance of extremes of oxygenation and ventilation, (4) monitoring for and treatment of seizures, and (5) ongoing treatment of the underlying arrest etiology and prevention of recurrent arrest.


Targeted temperature management


Hyperthermia following cardiac arrest is common in children and is associated with poor neurologic outcome. Therefore, proactive avoidance of fever should be a priority. However, whether a patient should receive therapeutic hypothermia has been a topic of substantial interest. Two large pediatric multicenter trials ( www.thapca.org ) in comatose survivors of OHCA and IHCA have failed to demonstrate a benefit of therapeutic hypothermia (32°C–34°C) compared with targeted normothermia (36°C–37.5°C). , However, it is worth noting that there was a nonsignificant trend toward improved rates of survival with hypothermia in the out-of-hospital study. As a result, the most recent PALS Guidelines recommended that for infants and children between 24 hours and 18 years of age who remain comatose after OCHA or ICHA, it is reasonable to use either targeted temperature management (TTM) of 32°C to 34°C followed by TTM of 36°C to 37.5°C or to use TTM of 36°C to 37.5°C. In either case, providers should ensure continuous measurement of temperature during the postarrest period and should aggressively avoid and treat fever (temperature of 38°C or more; class I recommendations).


Anticipation and prevention of hypotension


Postarrest myocardial dysfunction and arterial hypotension occur commonly after successful resuscitation. , , This postarrest myocardial stunning is pathophysiologically similar to sepsis-related myocardial dysfunction and postcardiopulmonary bypass myocardial dysfunction, including increases in inflammatory mediators and nitric oxide production. Four small observational studies after pediatric cardiac arrest have demonstrated lower rates of survival to hospital discharge when children exhibited hypotension after ROSC. , , , One of these studies associated post-ROSC hypotension (defined as a systolic blood pressure <5th percentile for age) after IHCA with a lower likelihood of survival to discharge with favorable neurologic outcome. Interestingly, only about half of the patients with hypotension in this study were treated, highlighting postarrest hypotension as an underrecognized therapeutic target. In response, the most recent iteration of the PALS Guidelines recommended that when appropriate resources are available, providers should both continuously monitor invasive arterial pressure after ROSC and use parenteral fluids, inotropes, and vasopressors to avoid/treat hypotension (class I recommendation).


Postarrest oxygenation and ventilation management


In children, hyperoxia is common and continuous normoxia is rarely achieved in the 6 hours following cardiac arrest. One report in pediatrics has demonstrated a survival benefit of normoxia (Pa o 2 ≥60 and <300 mm Hg) over hyperoxia (Pa o 2 >300 mm Hg). Similarly, hypocapnia (Pa co 2 <30 mm Hg) and hypercapnia (Pa co 2 ≥50 mm Hg) were both associated with mortality in pediatric observational studies. As such, the most recent PALS Guidelines made recommendations to avoid extremes of oxygenation and ventilation, with the understanding that avoiding hypoxemia is most important .


Monitoring for and treating seizures


Seizures are present in up to 30% of patients after cardiac arrest. Moreover, certain electroencephalographic findings (abnormal background, burst suppression, and subclinical status epilepticus) are all associated with worse neurologic outcome. Therefore, most experts agree that close monitoring and treatment of status epilepticus in the postarrest phase is important, although there is a paucity of data showing that treatment of seizures improves outcomes. In deciding on how to treat seizures in the postarrest period, providers must be aware of potential side effects of antiepileptic drugs and be prepared to treat them. For example, causing severe hypotension with benzodiazepines and/or other antiepileptic drugs may provide more harm than benefit.


Other considerations


Contemporary methods to improve cardiopulmonary resuscitation quality


Intra-arrest cardiopulmonary resuscitation quality monitoring technology


Innovative technology, primarily using force transducers and accelerometers, has allowed resuscitation scientists and clinicians to measure CPR mechanics quantitatively during actual resuscitation attempts. Research involving this technology has established the following as it pertains to pediatric cardiac arrest: (1) providing high-quality CPR is difficult even for professional rescuers, , (2) outcomes from pediatric cardiac arrest are directly associated with the quality of CPR provided, and (3) incorporation of CPR quality data into education and patient care is a vital component of any comprehensive resuscitation quality improvement program. In a single-center study, the combination of focused bedside training with audiovisual feedback before the resuscitation, automated defibrillator CPR feedback during the resuscitation, and post–cardiac arrest debriefing after the resuscitation improved guideline compliance and survival outcomes. In this study, favorable neurologic survival after pediatric ICU arrest improved from 29% to 50% with this approach. Currently, a clinical trial in the CPCCRN network funded by the National Heart, Lung, and Blood Institute is evaluating this resuscitation bundle of care to improve outcomes across 18 ICUs in the United States (ICU-RESUS: R01HL131544; trial completion anticipated March 2021). Recent work has also demonstrated that the use of a CPR coach, an individual solely focused on ensuring that CPR quality metrics are maintained during resuscitation, can improve CPR quality.


Point-of-care bedside training


There is a substantial body of evidence showing a decline in CPR skills as early as 3 months after conventional training. In response, resuscitation scientists have evaluated an alternative CPR training approached termed Rolling Refreshers . This is a point-of-care educational program that functions under a low-intensity, but high-frequency, paradigm—that is, trainees practice their CPR “on the job” with brief (<2 minutes) instruction/practice sessions. Several studies have established that this approach improves initial skill acquisition and retention in ICU and non-ICU providers alike during simulated resuscitation. The AHA now offers Basic Life Support (BLS) recertification through this transformational approach: cpr.heart.org/AHAECC/CPRAndECC/Training/RQI/UCM_476470_RQI.jsp .


Extracorporeal cardiopulmonary resuscitation


Extracorporeal membrane oxygenation (ECMO) has been increasingly used during resuscitation when standard CPR alone does not result in ROSC. In a large CPCCRN study of ICU CPR, more than 15% of the 77% of patients who achieved return of circulation did so through use of ECMO instituted during CPR. In children with medical or surgical cardiac diseases, Extracorporeal CPR (E-CPR) has been shown to improve survival to hospital discharge and can be effective even after prolonged CPR (>50 minutes). In a recent GWTG-R study that included patients from all illness categories who received at least 10 minutes of CPR, E-CPR was associated with improved rates of survival and favorable neurologic outcome at discharge compared with conventional CPR, even after propensity matching. The most recent PALS Guidelines states that E-CPR may be considered for pediatric patients with cardiac diagnoses but highlighted that existing ECMO protocols, expertise, and equipment should be in place. Suitability for E-CPR rescue should be individualized at the patient level with consideration of the reversibility of the underlying process in the ultimate decision rather than focusing on a specific disease category, such as cardiac versus noncardiac.


Controversies in pediatric cardiac arrest management


Airway management


As previously mentioned, most pediatric cardiac arrests are triggered by respiratory deterioration. As such, airway and ventilation management remain basic tenets of pediatric resuscitation. However, it must be noted that tracheal intubation of critically ill children is increasingly being recognized as high risk for precipitating cardiac arrest and that intubation during resuscitation can potentially detract from other therapies. Supporting that contention, a large observational cohort study demonstrated that tracheal intubation during cardiac arrest compared with no intubation is associated with worse rates of survival. Another identified that when intubation was not achieved on the first attempt, outcomes were worse. Similarly, a recent Cardiac Arrest Registry to Enhance Survival (CARES) study of pediatric OHCA found higher survival rates among children receiving bag-mask ventilation (BMV) compared with those who were intubated. As such, the 2019 PALS update states that BMV is reasonable when compared with advanced airway interventions for pediatric OHCA but was unable to make a recommendation regarding BMV versus advanced airway management for pediatric IHCA. Further study as to why tracheal intubation may be associated with worse outcomes (e.g., interruptions in CPR for the procedure, decreased venous return due to increased intrathoracic pressure, poor CPR quality as the team is distracted during tracheal intubation) are necessary.


Ventilation during pediatric cardiopulmonary resuscitation


Despite children having much higher ventilation rates at baseline and more pediatric cardiac arrests being associated with respiratory deterioration, CPR guidelines recommend a ventilation rate of 10 breaths/minute for both children and adults. This recommendation was made partly to simplify training but also to avoid the risk of excessive ventilation worsening hemodynamics, as is evident in some animal models of adult cardiac arrest. , In contrast to these animal studies, a recent multicenter CPCCRN study found that higher rates were associated with improved outcomes. Similar pediatric models have also found that higher rates may be beneficial to children. Cumulatively, these studies may indicate that future PALS Guidelines should reevaluate existing CPR ventilation rate recommendations for children and that prospective studies on this topic are needed.


Ventricular fibrillation and pulseless ventricular tachycardia


Pediatric VF/pVT has been an underappreciated problem. Believing that these lethal rhythms are rare in children can lead to a uniformly fatal outcome. Reports indicate that these shockable rhythms occur in 27% of pediatric IHCAs at some time during CPR. The treatment of choice for short-duration VF is prompt defibrillation. Adult studies have established that the mortality rate increases by 7% to 10% per minute of delay to defibrillation. In 2018, the corresponding pediatric study investigating the association between time to defibrillation and survival was published. Unlike the adult study, there was no association between delayed defibrillation and outcomes. These surprising findings were likely due to known differences between pediatric and adult IHCA. As a specific example, more pediatric IHCAs occur in ICUs in highly monitored patients. Presumably, these patients are more likely to receive immediate high-quality CPR, which may make time to defibrillation less important as high-quality CPR preserves the metabolic milieu for successful defibrillation longer. In short, more work is clearly needed regarding optimal defibrillation strategies in children. Regardless, a high index of suspicion for shockable rhythms, both as the initial rhythm and as subsequent rhythms later during cardiac arrest, and timely defibrillation when indicated remain of paramount importance.


Pediatric automated external defibrillators


Automated external defibrillators (AEDs) have improved adult survival from VF and are recommended for use in children 8 years or older with cardiac arrest. The available data suggest that some AEDs can accurately diagnose VF in children of all ages and rarely inaccurately recommend defibrillation. The energy doses delivered by AEDs are high, but they are below the range demonstrated to cause harm in laboratory animal studies of shock toxicity. Adapters with smaller defibrillation pads that dampen the amount of energy delivered have been developed as attachments to adult AEDs, facilitating their use in children. Given these advances, consensus guidelines recommend that AEDs be used in younger children, including infants, when manual defibrillators are not available. Importantly, recent data demonstrate relatively low rates of AED application to children with OHCA, suggesting that this as an area for additional education and training.


Summary


Outcomes from pediatric cardiac arrest and CPR have improved in recent decades. Perhaps the evolving understanding of pathophysiologic events during and after pediatric cardiac arrest and the developing fields of pediatric critical care and pediatric emergency medicine have contributed to these improvements. In addition, exciting breakthroughs in basic and applied science laboratories, such as physiologically directed CPR, are on the immediate horizon for further implementation. By strategically focusing therapies to specific phases of cardiac arrest, there is great promise that critical care interventions will lead the way to more successful cardiopulmonary and cerebral resuscitation in children.



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May 20, 2021 | Posted by in RHEUMATOLOGY | Comments Off on Performance of cardiopulmonary resuscitation in infants and children
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