The use of BMV is recommended rather than endotracheal intubation or SGA insertion for pediatric out-of-hospital cardiac arrest (OHCA) (Class IIb, Level C-LD). For pediatric in-hospital cardiac arrest, there is no comparable evidence for applying endotracheal intubation or SGA insertion and BMV to date.

It is recommended to provide dispatcher-assisted CPR with the help of emergency services for pediatric OHCA (Class I, Level C-LD). If bystander CPR is not performed for OHCA, it is recommended to provide dispatcher-assisted CPR using the help of emergency services (Class I, Level C-LD). The recommendation to provide dispatcher-assisted CPR if the bystander CPR is performed for pediatric OHCA cannot be set with the evidence available to date.

The rescuer should perform standard CPR with ventilation for infant and pediatric OHCA (Class I, Level B-NR). Although the bystander is unable to perform rescue breaths or has not been trained in it for pediatric OHCA, at least compression-only CPR should be done (Class I, Level B-NR).

It is not necessary to adjust the chest compression as per the measurements of ETCO₂. However, it can be helpful to measure the ETCO₂ if possible (Class IIb, Level C-LD).

Basic life support (BLS) in pediatric cardiac arrest has a considerable impact on the return of spontaneous circulation (ROSC) and survival rate; it begins with the prevention of cardiac arrest, which is the first step in the chain of survival. The pediatric chain of survival begins with the recognition of cardiac arrest and a rescue request. However, before this, the prevention of cardiac arrest begins with several institutional strategies for injury prevention and safety outside the hospital. In the hospital, it is important to make efforts to prevent cardiac arrest using an early warning system. The first three among the five elements in the survival chain belong to BLS (Fig. 1). Similar to that in adults, for children, providing rapid and effective CPR by laypersons is helpful to regain successful ROSC and neurological recovery. For children, the survival rate considerably varies depending on age and cause of cardiac arrest, and it increases with age. For pediatric in-hospital cardiac arrest (IHCA), the survival rate is as high as >40% [3].

A rescuer should verify the safety in the current area whenever CPR is performed. Theoretically, CPR has a risk of transmission of infectious diseases. Although the risk of rescuers being infected is very low, you must wear a mask and pay attention to personal protection during the COVID-19 pandemic.

First, check whether the patient needs CPR. If an unconscious patient is gasping or not breathing, you should determine that it is in cardiac arrest and requires CPR. Lightly tap the patient and shout, “Are you okay, kid?” If you know the name of that kid, call his/her name. Then, you should quickly check whether the child is injured and what medical treatment is required.

If the patient does not respond to stimulation and no one else is around, shout for help. If there are people around you, ask them to call 119 and bring an automated external defibrillator (AED). If no one is nearby, the first discoverer immediately calls 119 for rescue. Considering the high penetration rate in Korea, most rescuers have a cell phone. Therefore, the rescuer should stay on the scene and make the phone call right away. Inform the dispatcher regarding the state of the unconscious patient, request an AED, and perform the subsequent steps as per the instructions of the emergency-dispatcher. If the patient is unresponsive and there are two or more rescuers, the first rescuer immediately starts CPR, and the other rescuer activates the EMS while preparing for AED. If the rescuer is alone and does not have a cell phone, CPR must be first performed for 2 minutes, then EMS must be called, and nearby AED must be brought. The rescuer should return to the patient as soon as possible and use AED. If there is no AED, CPR with chest compression should be resumed.

Remove the patient’s upper garment, expose his/her chest, and verify the breathing. If the patient is regularly breathing, he does not require CPR. If there is no evidence of trauma, it can help maintain the airway and reduce the risk of aspiration to allow the patient to assume a recovery posture lying on his side. Repeatedly verify the patient’s breathing status until emergency rescuers arrive. Children with difficulty in breathing often take a posture where the airways will be more open and easier to breathe on their own. Therefore, if children with difficulty in breathing are attempting to take a more comfortable posture, let them maintain that posture. If the patient is unresponsive and is not breathing or is only gasping (cardiac arrest breathing), start CPR. If the patient’s gasping breath is mistaken for normal breathing, CPR may be occasionally delayed. You should also consider a state of gasping breath as non-breathing and then start CPR.

Proper chest compression during cardiac arrest maintains blood flow to major organs and increases the possibility of ROSC. If the infant or child is not responding and is not breathing, immediately perform chest compression 30 times. The compression depth and rate do not change in the 2015 PBLS guideline. The appropriate compression rate is 100–120/min, and the compression depth is one third of the anteroposterior diameter (chest thickness) at least or 4 cm depth in infants and 5 cm in children [9]. It is best to perform chest compression on a flat, hard surface. There are limited studies on children using feedback devices for chest compressions. For infants, the lay rescuer and healthcare provider should compress the sternum just below the line connecting the nipples using two fingers when they perform CPR alone. At this time, be careful not to press on the xiphoid process and ribs. For children, you should compress the lower half of the sternum using the heel of one or two hands. At this time, be careful not to press on the xiphoid process and ribs. Regardless of using one or two hands, minimum one third of the thoracic anteroposterior diameter (4–5 cm) should be maintained whenever compressing. It is important to ensure that the chest has completely recoiled to its normal position after each compression. Only when the chest completely recoils, the venous return to the heart can be sufficiently recirculated. Incomplete chest recoil is common during pediatric CPR, particularly when rescuers are exhausted. Incomplete chest recoil increases the pressure within the chest cavity and reduces venous return, coronary artery perfusion, cardiac output, and perfusion to cerebral arteries. Rescuer fatigue can make the speed, depth, and recoil of chest compressions inadequate. Even if the rescuer denies that he is exhausted and continues with CPR, the quality of chest compression will deteriorate within minutes. If there are two or more rescuers, they should take turns performing chest compression every 2 minutes. This prevents the rescuer from getting tired and decreasing the quality and speed of chest compressions. Taking turns in chest compression should be performed as soon as possible (ideally within 5 seconds) to minimize its interruption. For pediatric cardiac arrest, the lay rescuer should perform CPR by repeating cycles of 30 chest compressions and two ventilations until the EMS specialists arrive or the patient can breathe on his own. To obtain good results, for the pediatric and infant CPR in whom asphyxial cardiac arrest is common, chest compressions and ventilation should be administered together. The person who performs pediatric inhospital and out-of-hospital CPR should perform conventional CPR with ventilation and chest compressions. If the rescuer is unwilling or untrained to perform rescue breathing or if there is a situation in which ventilation is not possible, he should perform at least compression-only CPR until the EMS specialist arrives.

The ratio between chest compression and ventilation of one rescuer is 30:2. First, perform chest compression 30 times, open the airway, and then deliver ventilation two times. In infants or children who do not respond, the tongue may block the airway; therefore, regardless of trauma, open the airway by tilting the head and lifting the jaw.

Use either mouth-to-mouth or mouth-to-nose ventilation for infants or mouth-to-mouth ventilation for children. When breathing in, ensure that the chest rises and each breath takes 1 second. If the chest does not rise, verify the head position again to open the airway, close the mouth more tightly to prevent respiration leakage, and then attempt ventilation. Moreover, it is necessary to identify a position for optimal airway maintenance and effective ventilation by adjusting the degree of head tilt. If it is difficult to breathe via the mouth and nose at the same time when giving breath to infants, mouth-to-mouth or mouth-to-nose ventilation can be performed. For mouth-to-mouth ventilation, pinch the nose, whereas for mouth-to-nose ventilation, cover the mouth.

If there is only one rescuer, two ventilations after 30 chest compressions should be performed for as short a time as possible to minimize chest compression interruption time. If there are two rescuers, one person is in charge of chest compressions and the other is in charge of ventilation. After 30 chest compressions, sequentially perform ventilation twice. You should then make efforts to minimize chest compression interruption by ensuring that both chest compressions and ventilation are continuously performed.

After two ventilations, immediately perform 30 chest compressions. It takes approximately 2 minutes for one rescuer to perform five cycles of chest compressions and ventilations with a ratio of 30:2. If there are two rescuers, they should perform chest compressions and ventilation by turns after five cycles.

In the observational studies published since 2015 for infants and children, conventional CPR with ventilation showed a better overall prognosis than chest compression-only CPR without ventilation [10-14]. However, for infants, certain studies show a poor overall outcome regardless of the CPR methods. There have been reports that chest compression-only CPR showed outcomes similar to those of conventional CPR in children aged >8 years. For children, the prognosis was better when compression-only CPR was performed than not performing CPR at all. For infants, similarly, prognosis was poor when compression-only CPR was performed than not performing CPR at all, and conventional CPR with ventilation was associated with a good prognosis. Overall, conventional CPR with ventilation should be performed for infants and children. However, if the rescuer is unable or unwilling to perform ventilation, he should start compression-only CPR first; after that if possible, perform conventional CPR with ventilation.

A layperson who first witnesses a cardiac arrest may experience delays and difficulties in confirming cardiac arrest and performing CPR because he is not educated about it. Emergency service consultants can help the layperson to verify the cardiac arrest and perform CPR via telephone guidance. If a dispatcher instructs CPR over the phone for a pediatric OHCA patient, the possibility of performing CPR by rescuer increases and the time required to start CPR decreases [15-17]. Therefore, it is recommended to provide telephone-assisted CPR for pediatric OHCA. If the bystander is not undergoing CPR, the emergency consultant should be trained to help start CPR.

A rescuer should verify the safety in the current area whenever CPR is performed. Healthcare providers during the COVID-19 pandemic are recommended to use personal protective equipment (PPE) while performing aerosol-generating procedures in CPR. It is recommended that healthcare providers wear appropriate PPE, including masks, gloves, goggles, and surgical gowns, because chest compression and ventilation can cause the formation of aerosols and increase the risk of transmission of infection. When defibrillation is strongly recommended, it is suggested to actively implement it while paying attention to the transmission of infection (Fig. 6). Although compression-only CPR has a low risk of transmission of infection, it is suggested to cover the patient’s mouth if possible because there is a potential for aerosol generation. The rescuer should wash hands with soap and water or disinfect his hands with alcohol-based hand sanitizer as soon as possible as per infection control rules, and then change his clothes after finishing CPR. Moreover, the rescuer should contact local health authorities to verify for COVID-19 tests and self-isolation.

First, verify whether the patient requires CPR. Tap the patient lightly and shout, “Are you okay, kid?” If you know the name of that kid, call his name. Quickly verify whether the child is injured and what medical treatment is required.

If the patient is unresponsive and does not breathe (or gasping/abnormally breathing), ask someone nearby to call 119 and bring an AED. In the hospital, a witness immediately asks for help, ask a nearby person to bring a defibrillator, verify the pulse and breathing of the patient within 10 seconds, and start CPR if there is no pulse or breath.

If the infant or child has no response and is not breathing normally, the care provider should check his pulse. The pulse check time should not exceed 10 seconds. The pulse is verified in the brachial artery in infants and the carotid or femoral artery in children. If you cannot feel the patient’s pulse within 10 seconds or are unclear if there is a pulse, start chest compression [20].

If the infant or child is not responding and there is no breathing and pulse (or if it is unclear whether there is a pulse), start chest compression. The difference in method used by the healthcare provider and that by the lay rescuer lies in how to compress the chest in infants. When the healthcare provider is alone, two-finger chest compression is used for infants. When there are two or more rescuers, two-thumb encircling chest compression is performed. It is to stretch the hand and wrap the infant’s rib cage with both hands and strongly press the compression point of the sternum with both thumbs side-by-side.

The advantage of the two-thumb encircling chest compression is that it increases the coronary artery perfusion pressure more than that by the two-finger chest compression. It can consistently maintain adequate compression depth and force and can produce higher systolic and diastolic pressures. If you cannot hold the patient’s rib cage with both hands, just press the chest with two fingers.

The location of chest compression is the sternum right below the line connecting the nipples in infants and the lower half of the sternum in children. For one rescuer, the ratio of chest compression-to-ventilation is 30:2 using the two-finger chest compression. For two or more rescuers, the ratio of chest compression-to-ventilation is 15:2 using two-thumb encircling chest compression.

Open the airway by tilting the head and lifting the jaw, and perform rescue breathing twice after 30 chest compressions (15 compressions if there are two rescuers). If there are signs of trauma that suggest spinal damage, open the airway with a jaw lift rather than a head tilt. It is very important to open the airway and perform ventilation in pediatric resuscitation; therefore, if you cannot open the patient’s airway with only jaw-lifting, you should apply the head tilting regardless of the trauma.

If it is difficult to breathe through the mouth and nose at the same time when giving ventilation to infants, mouth-to-mouth or mouth-to-nose ventilation can be performed. For mouth-to-mouth ventilation, make the patient breathe through the mouth while pinching the patient’s nose. Confirm whether the patient’s chest rises when inhaling from both sides.

Ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) may be the cause of sudden cardiac arrest or occur during CPR. A sudden collapse in children with witnesses (e.g., collapse during exercise) is attributed to VF or pVT, requiring immediate CPR and rapid defibrillation. VF and pVF are classified as “shockable rhythm” because they respond to defibrillation.

For infants, it is beneficial to use a manual defibrillator if a well-trained healthcare provider has identified the shockable rhythm. The first energy dose is 2 J/kg and the second one is ≥4 J/kg during defibrillation, which should not exceed 10 J/kg or the maximum dose for adults [22].

If you do not have a manual defibrillator, use an AED with a pediatric impulse attenuator for infants. Use an AED with a pediatric energy attenuator or pediatric patches for children aged <8 years. However, if you have neither a manual defibrillator nor an AED with an energy attenuator, an AED for adults that cannot control the dose of energy can be used for infants.

Rescuers should minimize the interval time between chest compressions and defibrillation and resume CPR by immediately restarting chest compressions after one defibrillation. The AED encourages the rescuer to reanalyze the rhythm every 2 minutes, and the defibrillation should ideally be immediately performed after the chest compression.

Note that >90% of deaths by a foreign body aspiration occur in children aged <5 years, of which 65% occur in infants [23]. The clinical symptoms of airway obstruction by a foreign body include sudden shortness of breath, coughing, nausea, grunting, and wheezing. It suddenly occurs and has no previous fever or respiratory symptoms, which distinguishes it from other respiratory difficulties. Airway obstruction caused by foreign bodies can range from mild to severe. If airway obstruction is mild, the child may cough or make a sound. Symptoms suspected of complete obstruction include no speech, no sound when coughing, unable to breathe, cyanosis, or loss of consciousness; in this case, immediate treatment is required.

If it is determined that airway obstruction is severe in children aged >1 year, perform back blow until a foreign body comes out or consciousness disappears [24]. For infants, perform the back blow five times and chest thrust five times until a foreign body comes out or the consciousness disappears repeatedly [25,26]. Abdominal thrust is not performed in infants owing to the high risk of internal organ damage because the ribs do not sufficiently protect the epigastric organs and the liver is relatively large [25].

If the patient does not respond or his reaction disappears during the foreign body removal procedure, start CPR regardless of the presence or absence of a pulse [27]. However, if you can see a foreign body in the patient’s mouth before breathing after chest compression, use your fingers to remove it. If you cannot see a foreign body in the patient’s mouth, do not try to remove it using your fingers. This blind swabbing of the mouth may push the foreign body deeper into the pharynx or damage the pharynx [27,28]. After two ventilations, perform chest compression and ventilation repeatedly until the foreign body is removed. In fact, there are limited high-quality studies that can help determine guidelines for airway obstruction by foreign bodies. Most airway obstruction caused by a foreign body is resolved by letting the patient cough himself. However, in severe cases, the patient may need help from a rescuer [29,30].

Unintended trauma can be a leading cause of death in children and adolescents. Cardiac arrest by major blunt and penetrating injuries in children has a very high mortality rate [31-33]. Tension pneumothorax, hemothorax, lung injury, and cardiac tamponade can interfere with hemodynamics, oxygenation, and ventilation. Therefore, you should always suspect severe chest injury in patients with chest-abdominal trauma. Early treatment for reversible causes after cardiac arrest owing to penetrating trauma can increase survival [34,35]. It is recommended in the guidelines to control bleeding, recover circulating blood volume, secure airways, and treat tension pneumothorax for cardiac arrest caused by trauma. These procedures should be concurrently performed with standard CPR. The principles of basic CPR for injured children are the same as for children with common diseases; however, there is certain emphasis. Improperly performed CPR can increase preventable mortality. Errors in opening and maintaining the airways and errors caused by not recognizing internal bleeding are common in resuscitating children. The points to be noted when performing CPR in pediatric trauma patients are listed below [36]. 1) Cardiac arrest in pediatric trauma patients often occurs because breathing is not adequately maintained owing to hypovolemia by trauma. Therefore, it must be determined whether the airway and ventilation are maintained even in trauma patients. 2) If there is a possibility of airway obstruction because of broken teeth or blood, use a suction device. 3) If there is external bleeding, press to stop it. You should remove the patient’s clothes and check his entire body to determine the bleeding points. After verification, ensure to cover with a warm cloth such that hypothermia does not occur. 4) If there is a possibility that a spinal injury occurred judging by the mechanism of the injury, then minimize cervical spine movement and do not pull or move the head and neck. Open the airway by lifting the patient’s jaw and do not tilt the head. If the airway is not maintained by lifting jaw, secure the airway by tilting the head and lifting the chin. If there are two rescuers, one opens the airway and the other prevents cervical spine movement. At least the thighs, pelvis, and shoulders are fixed together on the spinal board. Because infants and toddlers have relatively large heads, the occipital part should be placed in a slightly recessed position than the torso, or the torso should be laid in a slightly elevated position and fixed to the spinal correction board to prevent cervical flexure [37]. 5) Transfer children with multiple organ trauma to a trauma center with a pediatric specialist if possible. 6) Open thoracotomy could be considered for children with no pulse with a penetrating injury [2,34,38-40]. However, there is still insufficient evidence to recommend performing emergency thoracotomy in children and infants without a pulse because of blunt trauma [41,42].

Drowning time is an important predictor of prognosis. Age, promptness of first aid, water type (freshwater or seawater), water temperature, and presence of witnesses will not be reliable prognostic factors [42]. For drowning in ice water, the rescue time can be extended because there is a possibility of survival even if the drowning time is long [43,44]. After removing the drowned children from water, initiate CPR immediately. Rescuers with special training initiate rescue breathing while underwater. Do not perform chest compressions in water because they are ineffective [45].

There is no evidence that water acts as a foreign body causing airway obstruction. Therefore, you do not waste time trying to drain water from the patient’s lungs [46]. Open the airway, perform rescue breathing twice, and start CPR with chest compressions. If there is one rescuer, perform chest compressions and ventilations five times cyclically at the ratio of 30:2, call the EMS, and ask for an AED. If there are two rescuers, the first rescuer continues CPR, whereas the second rescuer reports to the EMS and prepares an AED [47].

Children who require special medical assistance because of complications owing to chronic disease (e.g., blockage of tracheostomy), problems with auxiliary medical devices (e.g., ventilator malfunction), and exacerbation of the existing disease need appropriate management for their conditions. If there is no information on an existing disease, treatment plans, and current medications, you may have difficulty performing treatments. Parents or caregivers should copy the child’s medical information and place it at home, school, or care facility in advance. If the child is discharged from the hospital with a chronic or fatal illness, parent, school nurse, and home care provider should be aware of information about the reason for hospitalization, the condition during the hospitalization, and any symptoms that may worsen as well as receive training for CPR in special circumstances [48].

Rapid response systems have been employed in several medical institutions to prevent cardiac arrest by detecting physiological changes in hospitalized patients early and to reduce admission to the intensive care unit [51]. This is to identify the clinical deterioration of the patient due to a delay of a call to medical staff in a hospital. It is an active effort to issue an early warning of changes in a patient’s condition by scoring blood pressure, pulse, respiratory rate, body temperature, oxygen saturation, and level of consciousness [52].

The use of a pediatric early warning score has reduced the incidence of cardiac arrest, length of stay in the hospital, and mortality as well as unplanned transfer to the pediatric intensive care unit [53,54]. However, there are not many studies on the frequency of early response as per the working hours of the rapid response team (RRT) and the patient’s prognosis, and there is currently no consensus on the standard for activating the domestic RRT; therefore, continuous further study is required [55].

Moreover, when using pediatric early warning scores in medical institutions, it is necessary to discuss how to organize items to sensitively identify changes in the patient’s condition. It is necessary to discuss whether to include only vital signs or also include sepsis, dyspnea, anaphylactic shock, hypovolemic shock, obstructive shock, arrhythmia, and metabolic acidosis [48]. Moreover, it is necessary for the medical staff to quickly recognize and respond after discussing how to identify the false positive alerts of early warning score.

RRT is a department dedicated to first aid and monitoring of patients with deteriorating conditions in the hospital. It is composed of specialized medical staff to quickly identify and respond to signs that appear before a cardiac arrest occurs. Depending on the hospital’s resources, the composition, operation method, and activation of the rapid response system can be adpated. Medical institutions form RRTs to better understand the patient’s respiratory system, cardiovascular system, and changes in consciousness, and it comprises skilled medical staff for rapid intervention and efficient critical care management [56,57].

There is not sufficient evidence that the operation of the pediatric RRT increases the rate of ROSC and decreases the mortality rate of pediatric cardiac arrest in hospitals. However, studies are showing that it reduces the incidence of pediatric cardiac arrest in hospitals, particularly outside the intensive care unit [58-61]. In one cohort study, for children requiring unplanned admission to the pediatric intensive care unit, RRT implementation was associated with reduced mortality [62]. Therefore, medical institutions with trained professional staff may consider establishing and operating a pediatric RRT to prevent the occurrence of cardiac arrest.