AHA CPR guidelines: What the 2015 PALS updates mean for EMS providers

In-depth insights into the expert recommendations for chest compressions, defibrillation, medications and post-arrest care


The 2015 American Heart Association (AHA) Guidelines Update for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) made several new changes for pediatric care associated with resuscitation from cardiac arrest. In deciding what topics needed evidence review for the newest guidelines, the Pediatric ILCOR Task Force reviewed topics from the 2010 guidelines, and developed three BLS-related and 18 ALS-related questions. For topics not chosen, the recommendations made in 2010 remain in place.

CPR sequence: compressions or ventilations

One of the three topics chosen for systematic review in 2015 is whether CPR should begin with chest compressions or with rescue breathing. In infants and children asphyxial cardiac arrests are more common than cardiac arrests following the sudden development of ventricular fibrillation [1]. In those instances, lay rescuers providing conventional CPR that combines chest compression with rescue breathing produced more favorable neurologic outcomes compared to providing chest compression only [2]. 

However, experts have still not identified whether beginning CPR with rescue breathing (A-B-C approach) or chest compressions (C-A-B approach) is optimal. The AHA based the 2010 recommendation to adopt the C-A-B approach in pediatric BLS on establishing consistency in training between adult and pediatric CPR.

Since 2010, results from a retrospective review of lay rescuer response to out-of-hospital (OOH) cardiac arrest in children supports previous data suggesting conventional CPR increases the odds of favorable neurologic outcome compared to compression-only CPR [3]. In that study compared to chest compression only, children who received both chest compressions and rescue breathing were almost two and a half times more likely to have one-month favorable neurologic outcome regardless of the etiology of the arrest.

Unfortunately, there are no outcome studies comparing A-B-C to C-A-B in either the adult or the pediatric populations. The AHA believes it is still reasonable to begin the sequence with chest compression and follow the C-A-B approach.

Chest compression rate and depth

Because of the lack of evidence for identifying the optimal rate of chest compressions in infants and children, the pediatric task force writing team agreed to use the same rate recommended by the BLS team for adults. Therefore, it is reasonable to provide between 100-120 chest compressions per minute for both infants and children.

As with adults, the optimal chest compression depth for children is unknown. One case series involving six infants demonstrated that increasing the depth of chest compressions from one-third to one-half the anterior-posterior diameter of the chest resulted in a 62 percent increase in systolic blood pressure, as measured by an indwelling arterial blood pressure monitor [4]. Researchers in Pennsylvania also found that compared to more shallow chest compressions, the odds of survival for at least 24-hours was 10 times higher for patients when 60 percent of the chest compressions in the first five minutes of the resuscitation attempt were deeper than 51 mm [5]. (For more information on the subject read the article, "Prove It: Pushing hard improves cardiac arrest outcome for pediatric patients"). 

It is reasonable for health care providers to push to a depth of at least one-third the anterior-posterior diameter of the infant or child’s chest. This should correspond to about 1 ½ inches in depth for the infant and about 2 inches in the child. Once the child reaches puberty, health care providers should compress the chest to the depth recommended in the adult standards.

Because many health care providers do not even consistently meet the recommendations for rate and depth made in the 2010 guidelines [6-8], the consensus of the group was for health care teams to employ real-time feedback devices as a way of improving CPR quality during the resuscitation.

Compression-only CPR for children

The final BLS question addressed the effectiveness of compression-only CPR for the pediatric patient.

The 2010 guidelines emphasized the need for both compression and ventilation in the CPR sequence for both infants and children [1]. However, compression-only CPR was preferred over no CPR.

There are no studies that compare outcomes between patients who receive conventional CPR from health care providers and patients who receive compression-only CPR from health care providers. Since 2010, one prospective study examining bystander CPR demonstrated that for OOH arrest of presumed cardiac etiology in infants and children, favorable neurological outcome between those who received compression-only CPR was not different from those who received conventional CPR [2]. 

On the other hand, for arrests of noncardiac etiology, favorable neurological outcome was more likely if the patient received conventional CPR that combined both compression and ventilation. A more recent study actually found worse neurological outcomes associated with bystander-provided compression-only CPR [3]. As a result, the AHA continues to recommend that health care providers deliver both ventilation and chest compressions for pediatric patients in cardiac arrest.

Monitoring physiologic parameters during the resuscitation attempt

As with adult patients, the 2015 guidelines recommend health care providers monitor physiological parameters during the resuscitation attempt. Also similar to the adult patient is the realization that carbon dioxide (CO2) elimination is likely the only recommended physiologic parameter that can be easily monitored in the field.

The 2010 guidelines recommended that health care providers attempt to improve the quality of CPR when the end-tidal carbon dioxide (ETCO2) levels are consistently below 15 mmHg [1]. Despite the fact there are no studies correlating ETCO2 levels with survival in children who suffer cardiac arrest, the AHA continues to recommend using ETCO2 levels as a proxy measure of CPR quality, but has removed the specific values in the 2015 guidelines.

Vasopressor use during resuscitation

Evidence of the effectiveness of administering vasopressors to children who suffer a cardiac arrest is even sparser than for adult patients. One observational study of nine children (median age 10.7 years) who developed cardiac arrest while participating in a sporting event or some type of physical exertion found that all of the survivors (n = 6) received bystander CPR within 2 minutes of collapse and EMS defibrillation within 10 minutes of collapse [9]. 

Of those six, five (83 percent) received no epinephrine during the resuscitation attempt. However, since timing of ROSC was not reported, it is possible the survivors responded well to early defibrillation shocks thereby making epinephrine administration unnecessary.

One small randomized control trial involving 68 children could find no difference in ROSC between those who received standard dose epinephrine and those who received high-dose epinephrine after failing to respond to an initial standard epinephrine dose [10]. Worse, children who received high-dose epinephrine had lower rates of 24-hour survival compared to the standard dose group.

In a retrospective cohort study, researchers found an inverse relationship between the number of epinephrine doses administered and survival to hospital discharge [11]. Using logistic regression, epinephrine use was independently associated with reduced survival rates in that study.

An in-hospital study of cardiac arrest from nonshockable rhythms found delays in epinephrine administration resulted in decreased survival rates [12].

Three small retrospective case series demonstrated some benefits associated with vasopressin [13] or terlipressin, a longer-acting analogue of vasopressin, administration [14,15] after patients failed to respond to traditional resuscitation measures. In the largest retrospective database review of children suffering in-hospital cardiac arrest, vasopressin administration was associated with decreased likelihood of achieving or sustaining ROSC [16].

The final recommendation by the AHA is that it is reasonable to administer a single dose of epinephrine every 3-5 minutes for children suffering cardiac arrest.

Antiarrhythmic use during resuscitation

Based on the results from two pediatric case series [17,18] and extrapolation from adult studies [19,20], the 2010 guidelines recommended the use of either amiodarone or lidocaine for children who suffer shock refractory ventricular fibrillation or pulseless ventricular tachycardia (VF/pVT) [1].

Since 2010, one observational in-hospital study concluded that lidocaine administration to children suffering from VF/pVT was independently associated with improved ROSC and 24-hour survival although neither lidocaine nor amiodarone was associated with increased survival to hospital discharge [21].

With no new strong evidence to contradict the 2010 recommendation, the AHA continues to recommend either amiodarone or lidocaine for shock refractory VF/pVT in children.

Defibrillation

The 2010 guidelines recommended an initial energy dose of 2-4 J/Kg. For refractory VF/pVT, the recommendation for the second shock was 4 J/Kg. The recommendation for all subsequent shocks was 4-10 J/Kg.

For the 2015 recommendations on defibrillation energies in children, there were no studies that addressed survival to one-year or harm to the patient. One observational in-hospital study of defibrillation energies in children found that an initial shock of 2 J/Kg resulted in successful termination of Vf/pVt only 55 percent of the time [22]. Based on this result, it is tempting to advocate for a higher first shock energy setting. However, those patients who received an initial first shock of 4 J/Kg had lower incidence of both termination of VF with ROSC and survival of the VF/pVT event.

One additional observational study of in-hospital cardiac arrest found no significant differences in survival to hospital discharge rates between children who received an initial defibrillation dose of 2-4 J/Kg and any other defibrillation dose [23]. Because the optimal energy dose for infant and child defibrillation remains unknown, the AHA considers the continued practice of delivering an initial dose of 2-4 J/Kg to be reasonable. For refractory rhythms, it is also reasonable to deliver a second shock at 4 J/Kg with all subsequent shocks at 4-10 J/Kg.

Targeted temperature management

Previous recommendations to consider initiating targeted temperature management in children derive largely from extrapolated adult studies [24,25] and from studies of asphyxiated newborns [26,27].

Compared to normothermia, two observational trials of pediatric cardiac arrest occurring both in and out of the hospital could not find advantages in survival or functional outcome related to implementation of hypothermia following ROSC [28,29]. However, one observational study of cardiac arrest occurring in either the in or OOH environment found that maintenance of mild hypothermia (33 C) for 72 hours resulted in improved survival rates compared to the normothermia group [30]. For the survivors however, there was no difference in functional outcome.

More importantly, results from a large multicenter prospective randomized trial found that implementing and maintaining mild therapeutic hypothermia in comatose children who survived OOH cardiac arrest did not improve functional outcome at 1-year following cardiac arrest when compared to normothermia [31].

Based on this new information, the AHA altered previous guidelines to now recommend that for children who suffer an OOH cardiac arrest, it is reasonable for the hospital to maintain five days of continuous normothermia or alternatively, two days of mild hypothermia followed by three days of continuous normothermia. There is no recommendation for EMS to initiate cooling in the field.

Oxygen use during the post-cardiac arrest phase

The 2010 guidelines warn against hyperoxia during the post-resuscitation phase, recommending that health care providers ventilate with the least amount of oxygen necessary to achieve arterial oxyhemoglobin saturation of 94 percent [1]. Three small observational studies found hyperoxia common during the first 6-24 hours after ROSC although the researchers could not find an association with worse outcome [32-34].

A larger retrospective analysis of the Pediatric Intensive Care Audit Network found the risk of death in the intensive care unit increased with both hypoxia and hyperoxia during the post resuscitation period [35].

In response, the AHA continues to recommend that as soon as arterial oxyhemoglobin saturation levels can be reliably monitored, health care providers attempt to achieve normoxemia. This requires careful titration of oxygen delivery to achieve an oxyhemoglobin saturation of less than 100 percent but not less than 94 percent.

Resuscitation science has improved significantly since the introduction of closed chest compression more than 50 years ago. The 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care provides the most scientifically sound recommendations for improving survival among children who suffer cardiac arrest.

References

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