Apnea of Prematurity

Definition

Intermittent Hypoxia - short and repetitive episodes of hypoxemia and desaturation which not accompanied by bradycardia and apnea

central apnea (40%)- inspiratory efforts are absent
obstructive apnea (10%) - inspiratory efforts present, but airway obstruction is cause of hypoxia
Mixed apnea (50%) - airway obstruction precedes central apnea most common cause of apnea

premature infants (almost all babies <28 weeks)
present within week of birth
cease by 34 to 37 weeks of PMA
apnea in late preterm/term born infants - always associated with serious identifiable causes such as sepsis, hypoglycemia, birth asphyxia, intracranial hemorrhage, seizure, depression

check hypoxia, bradycardia, and loss of tone
stimulate the baby
if no response to stimulation, start PPV (preferably with T-piece), with mixed air and oxygen
CPAP and HFNC can be considered
intubation and ventilation

Cause	Signs	Evaluation
Airway	secretion, KMC, feed regurgitation	correct feeding position
Metabolic disorders	Jitteriness, lethargy, fedding difficulty, CNS depression	Glucose, calcium, blood gas, electrolytes
Infection	Not looking well, lethargy, temperature, shock, sugar,	Blood culture, urine culture, CBC, CRP, CSF examination
NEC	feed intolerance, GI aspirate	Abdominal X ray
Anemia	blood loss	Hematocrit
Impaired oxygenation	hypoxia, tachypnea, RD	BG analysis, CXR
Temperature instability	lethargy	monitor temperature
Drugs	antenatal MgSO4, Antinatal AED	check drug level
IVH	seizure, pallor, bulging fontenalle	USG cranium
Inborn errors of metabolism	Jitteriness, poor feeding, lethargy, irritablity, CNS depression	lactate, ammonia, metabolic screening
PDA	tachycardia, bounding pulse, murmur, hyperkinetic precordium	CXR, Echo

AOP Algorithm

Drug of choice
MOA : antagonism of adenosine receptors
half life 5-7 days
uses of caffeine in AOP
1. stimulation of respiratory center of medulla
2. enhances diaphragmatic contractility
3. increased sensitivity to carbon dioxide
4. mild diuretic effect
5. increases minute ventilation
6. decreases periodic breathing
uses of caffeine in BPD
1. reduce BPD through immunomodulatory effect
2. antioxidant
3. antifibrotic
4. antiapoptotic
5. regulation of angiogenesis
6. diuretic effects
adverse effects of caffeine
- tachycardia
- hypoglycemia
- increased metabolism
- sleep disturbances
indications
- preemies with risk of apnea
- prior to extubation of ventilated preterm <32 weeks (<34 weeks - WHO)
- limited prophylactic use
- earlier caffeine use in 1st 3 days of life is beneficial
loading at 20 mg/kg over 30 mins followed by 5mg/kg maintenance
higher doses (30 to 80 mg/kg) can be tried if poor response to conventional doses, increased risk of IVH
stop caffeine when child reaches 32 weeks (or 34 weeks if child born very preterm)