What is the most likely diagnosis for a 7-day-old premature infant with episodes of desaturation, noisy breathing, and central apneas during sleep?

Primary Central Sleep Apnea of Prematurity

The most likely diagnosis is primary central sleep apnea of prematurity (option b). This 7-day-old infant born at 32 weeks gestation presents with the classic hallmarks of apnea of prematurity: multiple central apneas lasting 25 seconds during REM sleep, periodic breathing exceeding 5 minutes, and desaturation episodes, all occurring in the absence of craniofacial abnormalities or significant hypoventilation 1, 2.

Key Diagnostic Features Supporting Apnea of Prematurity

The clinical presentation is pathognomonic for apnea of prematurity in this premature infant:

• Gestational age of 32 weeks places this infant at high risk, as apnea of prematurity is a diagnosis reflecting CNS immaturity in premature infants 3, 1
• Central apneas lasting 25 seconds during REM sleep are characteristic, as premature infants have altered ventilatory responses and immature respiratory control that worsens during REM sleep 1, 4
• Periodic breathing lasting >5 minutes is a common manifestation of the immature respiratory control seen in premature infants 4
• Episodes of desaturation are expected findings, as desaturation is more common during REM sleep in infants with respiratory immaturity 4, 5
• Age of 7 days (approximately 33 weeks postmenstrual age) falls within the typical presentation window for apnea of prematurity 1

Why This is NOT Congenital Central Hypoventilation Syndrome

Congenital central hypoventilation syndrome (CCHS) is effectively ruled out by the normal CO2 values:

• Mean transcutaneous CO2 of 39 mmHg with only 1% of sleep time >50 mmHg is normal and excludes hypoventilation syndromes 4
• CCHS characteristically presents with severe hypoventilation during sleep with markedly elevated CO2 levels, which is absent in this case 4
• The presence of brief obstructive events and periodic breathing is more consistent with apnea of prematurity than CCHS 1

Why This is NOT Obstructive Sleep Apnea

Obstructive sleep apnea is not the primary diagnosis despite "several brief obstructive events":

• The predominant finding is multiple central apneas, not obstructive events 1, 2
• No micrognathia or craniofacial abnormalities are present, which are major risk factors for infant OSA 4
• The infant is only 7 days old at 32 weeks gestation—OSA in infants typically requires anatomic predisposition (micrognathia, laryngomalacia, craniofacial abnormalities) which are explicitly absent 4
• The brief obstructive events noted are likely secondary phenomena related to the immature respiratory control and pharyngeal muscle tone during apneic episodes in premature infants 1

Clinical Management Approach

Immediate management should focus on standard apnea of prematurity protocols:

• Caffeine citrate therapy is the mainstay of treatment for central apnea in premature infants, with a loading dose of 20 mg/kg followed by 5 mg/kg daily maintenance 6, 1
• Continuous cardiorespiratory monitoring should continue given the significant apneas and desaturations 4, 7
• Supplemental oxygen may be needed if desaturations persist, particularly during REM sleep when episodes are most severe 4, 5
• Prone positioning can help reduce obstructive components if they persist 1

Important Clinical Pitfalls to Avoid

• Do not pursue extensive workup for CCHS when CO2 levels are normal—this would lead to unnecessary genetic testing, anxiety, and cost 4
• Do not focus treatment on the brief obstructive events when central apneas are the predominant pathology 1, 2
• Do not assume this requires polysomnography for ongoing management—the bedside study has already confirmed the diagnosis, and routine PSG is not indicated for uncomplicated apnea of prematurity 4
• Recognize that apnea of prematurity is a diagnosis of exclusion—ensure sepsis, metabolic disturbances, anemia, and CNS disorders have been appropriately ruled out before attributing events solely to prematurity 6

Expected Clinical Course

The prognosis for apnea of prematurity is favorable:

• Most infants show significant improvement with caffeine therapy, with mean days of zero apnea events increasing from 1.2 to 3 days in treated infants 6
• Central apnea typically resolves as the infant matures, with significant reduction in central apnea-hypopnea index by 12-14 months corrected age 2
• Caffeine elimination is slow in premature infants (half-life 3-4 days) due to immature hepatic function, but metabolism normalizes by 9 months of age 6