Apnea and Bradycardia

• Central:  No brainstem stimulation to breathe.  Airflow and chest movement stop.
• Obstructive:  Airway obstruction.  No airflow, disorganized chest movements continue.  May be obstruction may be positional, occur post extubation, be due to collapse of an immature airway, or be secondary to GE reflex.
• Mixed:  Airflow stops followed by loss of chest wall movement; components of central and obstructive apnea.
• Periodic breathing:  A pattern of at least 3 cycles of regular respirations of 10-18 seconds each interrupted by pauses of at least three seconds.  Reported as the percentage of quiet time spent in this pattern.  Significant if associated with bradycardia and/or desaturation episodes.

• CNS:  Asphyxia, intracranial hemorrhage, seizures, sedation, malformations, vagal stimulations, gastroesophageal reflux, NG/ET-tube placements.
• Pulmonary:  Airway secretions, collapse, or obstruction; RDS, hypo/hyperinflation, hypoxia
• Systemic:  Infection, shock, necrotizing enterocolitis, congestive heart failure, patent ductus arteriosus, hypo- or hyperthermia, anemia.
• Anatomy: Choanal atresia or stenosis; micrognathia, macroglossia, tracheomalacia, tracheal stenosis, position.
• Metabolic: Hypoglycemia, hyponatremia, hypocalcemia, inborn errors of metabolism.

Treatment:

• Treat the underlying cause (give glucose, antibiotics, oxygen, rbcs, etc.)
• For signficant apnea of prematurity, theophylline can be given to increase central drive
• Load 5-6 mg/kg
• Maintenance dose 1-2 mg q 6-8 hours
• Check level prior to fifth dose
• Alternately, caffeine can be given to increase CO2 sensitivity, stimulate diaphragmatic contraction, decrease muscle fatigue, and increase metabolic rate and catecholamine activity.
• Load 10 mg/kg
• Maintenance dose 5 mg/kg
• Check level prior to fifth dose, or monitor for clincal effect
• Theophylline is better in cases with BPD as it also inhibits bronchospasm.  However, it is worse for GER.
• NCPAP can be employed
• Splints the upper airway, improves oxygenation and stimulates the baby.
• Intubate if necessary for severe or recalcitrant cases.

Routine Monitoring

• Always record all associations with events such as pre-, during, and post-feeding, sleep state, choking, regurgitation, desaturation, need for stimulation and how vigrorous.  A common pattern of apnea of prematurity is apnea followed by bradycardia and/or desaturation.  Human visual observation alone based on routine cardiopulmonary monitoring in the NICU picks up only a portion of the events (eg, just the bradycardia and desaturations) but misses the apnea that initiated it.  Most of the bradycardia/desaturation events are preceded by apnea whether observed or not.  Vagal stimulation (eg, NG tube placement) may produce bradycardia alone.  Other causes of events may produce different patterns.  Chest wall movement itself does not prove air movement.

 Trend Studies

• Event recording:  Documents the presence of apnea and bradycardia.
• Multichannel Oxipneumogram: Differentiates central, obstructive and mixed apnea.
• Polysomnogram: Includes EEG, ocular/chin/abdominal movement, and end tidal CO₂ monitoring to determine sleep states and association with seizures.