[Autonomic regulation and bradycardia during the neonatal period]

Cardiorespiratory Events in Infants Born Preterm during the Transitional Period

OBJECTIVE

To investigate the features of cardiorespiratory events in infants born preterm during the transitional period, and to evaluate whether different neonatal characteristics may correlate with event type, duration, and severity.

STUDY DESIGN

Infants with gestational age (GA) <32 weeks and/or birth weight <1500 g were enrolled in this observational prospective study. Heart rate (HR) and peripheral oxygen saturation (SpO₂) were recorded continuously over the first 72 hours. Cardiorespiratory events of ≥10 seconds were clustered into isolated desaturation (SpO₂ <85%), isolated bradycardia (HR <100 bpm or <70% of baseline), or combined desaturation/bradycardia and classified as mild, moderate, or severe. The daily incidences of isolated desaturation, isolated bradycardia, and combined desaturation and bradycardia were analyzed. The effects of relevant clinical variables on cardiorespiratory event type and severity were assessed using generalized estimating equations.

RESULTS

Among the 1050 events analyzed, isolated desaturations were the most frequent (n = 625) and isolated bradycardias the least common (n = 171). The number of cardiorespiratory events increased significantly from day 1 to day 2 (P = .028). One in 5 events had severe characteristics; event severity was highest for combined desaturation and bradycardia (P < .001). Compared with other event types, the incidence of combined desaturation and bradycardia was inversely correlated with GA (P = .029) and was higher with the use of continuous positive airway pressure (P = .002). The presence of a hemodynamically significant patent ductus arteriosus was associated with the occurrence of isolated desaturations (P = .001) and with a longer duration of cardiorespiratory events (P = .003).

CONCLUSIONS

Cardiorespiratory events during transition exhibit distinct types, duration, and severity. Neonatal characteristics are associated with the clinical features of these events, indicating that a tailored clinical approach may reduce the hypoxic burden in preterm infants aged 0-72 hours.

[Apparent life-threatening events and sudden unexpected death in infancy: Two different entities]

Most infant apparent life-threatening events (ALTEs) are minor with spontaneously favorable prognosis. Frequent etiologies are gastroesophageal reflux, obstructive apneas, respiratory infections, and breath-holding spells. Some rare but potentially serious causes must be discussed. Diagnosis is usually guided by careful questioning of the parents and repeated clinical examinations. A few complementary examinations are systematically needed and their performance is increased if they are oriented by clinical aspects. Hospitalization is usual for monitoring, further etiological investigation, and management of parental anxiety. ALTE and sudden unexpected death in infancy (SUDI) etiologies are often different. SUDI is called sudden unexplained death in infancy if it remains unexplained after investigation including autopsy. The annual incidence in France fell sharply after prevention campaigns in the 1990s, and now is about 400 SUDI, including 250 unexplained SUDI. The main guidelines of prevention are back sleeping, cessation of smoking during and after pregnancy, securing the bed and bedding, prevention of hyperthermia, and avoidance of dangerous factors of bed sharing. In the future, infants with particular vulnerabilities may be identified. The Haute Autorité de santé (French National Authority for Health) has published guidelines to support SUDI, standardize procedures, and improve our understanding of the causes of death.