Overview
Definition:
Chest compressions are a critical intervention in neonatal resuscitation when the heart rate remains inadequate despite effective positive pressure ventilation (PPV)
They are initiated to improve systemic perfusion and oxygen delivery to vital organs when the neonate's heart is not beating effectively.
Epidemiology:
While precise incidence varies, cardiorespiratory events requiring chest compressions are uncommon in term newborns but are a significant cause of mortality and morbidity in preterm infants and those with congenital anomalies
The need for compressions underscores a failure of initial resuscitation steps.
Clinical Significance:
Accurate identification of indications for chest compressions is paramount for successful neonatal resuscitation
Delays or inappropriate initiation can lead to irreversible hypoxic-ischemic injury or unnecessary intervention
This skill is vital for all neonatologists, pediatricians, and emergency physicians.
Guidelines Reference:
Current guidelines from the Neonatal Resuscitation Program (NRP) and the International Liaison Committee on Resuscitation (ILCOR) provide the framework for initiating chest compressions.
Indications
Heart Rate Threshold:
Persistent heart rate (HR) below 60 beats per minute (bpm) despite 30 seconds of effective positive pressure ventilation (PPV) with 100% oxygen
Effective PPV is characterized by visible chest rise.
Assessment Of Hr:
Heart rate should be assessed by auscultation of the apical impulse or palpation of the umbilical cord
If auscultation is difficult, consider observing chest wall movements or using ultrasound if immediately available.
Failure Of Ppv:
The decision to initiate compressions implies that PPV alone has not restored adequate cardiac output
The goal is to augment circulation when the heart is failing to do so.
Accompanying Signs:
Often accompanied by signs of poor perfusion such as pallor, mottling, weak pulses, and hypotonia
However, HR below 60 bpm is the primary trigger for compressions, even in the absence of these signs initially.
Hypoxia Vs Primary Cardiac:
While hypoxia is a common cause of bradycardia in newborns, primary cardiac issues can also occur
The resuscitation algorithm addresses both, but chest compressions are indicated for HR < 60 bpm regardless of the initial presumed cause after PPV failure.
Cardiac Arrest Management
Initial Steps:
Ensure effective PPV with 100% oxygen and adequate chest rise
If HR remains < 60 bpm after 30 seconds of PPV, begin chest compressions
Simultaneously, ensure proper airway positioning and consider adjuncts like suctioning if needed.
Compressions Technique:
Two primary techniques: the two-thumb encircling hands technique (preferred for effective compression and depth) or the two-finger technique
Compressions should be performed on the lower third of the sternum, avoiding the xiphoid process.
Compression Depth:
Compress the sternum approximately one-third of the anterior-posterior diameter of the chest, or about 1.5 cm (0.6 inches).
Compression Rate:
Aim for a rate of 100-120 compressions per minute
The ratio of compressions to ventilation is 3:1 (three compressions followed by one ventilation).
Ventilation Synchronization:
During the 3:1 cycle, deliver a breath over 1 second
Ensure the ventilation is coordinated with compressions to achieve an effective cardiac output
After each cycle of 30 compressions and 10 ventilations, reassess the heart rate.
Medication Administration:
If HR remains < 60 bpm after 3 cycles of compressions and ventilations (approximately 2 minutes), administer epinephrine (adrenaline) intravenously or intraosseously
The dose is 0.01 mg/kg (0.1 mg/mL concentration)
Follow with further compressions and ventilations and reassess HR.
Monitoring And Reassessment
Heart Rate Monitoring:
Continuous monitoring of the heart rate is crucial
Reassess the heart rate after 30 seconds of effective PPV or after 2 minutes (approximately 3 cycles) of CPR.
Chest Rise Assessment:
Adequate chest rise is the most important indicator of effective PPV
If chest rise is not achieved, troubleshoot the airway: reposition the head, clear the airway, open the mouth, increase pressure, or consider an alternative airway.
Circulation Assessment:
After effective CPR for 2 minutes, reassess HR, presence of spontaneous circulation, and signs of perfusion (e.g., umbilical artery/vein patency for access, pulses).
When To Discontinue:
Chest compressions can be discontinued if the heart rate reliably increases to > 60 bpm and spontaneous effective breathing is established.
Differential Diagnosis Of Bradycardia
Hypoxia:
The most common cause of bradycardia in neonates, especially preterm infants
Correcting hypoxia with PPV is the first-line management.
Hypothermia:
Low body temperature can significantly depress cardiac function
Warming the infant is essential.
Metabolic Derangements:
Electrolyte imbalances (e.g., hyperkalemia, hypocalcemia) and hypoglycemia can affect cardiac contractility and rhythm.
Congenital Heart Disease:
Certain complex congenital heart diseases may present with bradycardia, especially if there is an underlying obstructive lesion or myocardial dysfunction.
Drug Effects:
Maternal administration of certain medications during pregnancy or medications given to the neonate can lead to bradycardia.
Key Points
Exam Focus:
Remember the threshold for chest compressions: HR < 60 bpm despite 30 seconds of effective PPV with 100% oxygen
The 3:1 compression-to-ventilation ratio is critical
Epinephrine is the first-line drug for persistent bradycardia.
Clinical Pearls:
During compressions, ensure adequate depth (1/3 chest diameter) and rate (100-120/min)
The two-thumb technique is preferred
Always aim for chest rise with ventilations
Coordinate compressions and ventilations smoothly.
Common Mistakes:
Initiating compressions too early without ensuring effective PPV first
Inadequate compression depth or rate
Incorrect compression-ventilation ratio
Delaying epinephrine administration when indicated
Failure to troubleshoot airway issues if chest rise is absent.