Determination of cardiac reserve in preterm infants

Area of Science:

• Neonatal Cardiology
• Pediatric Physiology

Background:

• Assessing cardiac reserve in preterm infants is crucial for monitoring their physiological development.
• Phonocardiography offers a non-invasive method to evaluate cardiac function in neonates.

Purpose of the Study:

• To determine cardiac reserve in preterm infants using phonocardiogram parameters.
• To investigate the relationship between gestational age and cardiac function indicators.
• To assess the impact of stimulation (crying) on cardiac reserve in preterm neonates.

Main Methods:

• Phonocardiography was used to measure the ratio of the first heart sound to the second heart sound (S1/S2), the ratio of diastolic to systolic duration (D/S), and cardiac contractility change trend after stimulation (CCCTS).
• Measurements were taken in 154 preterm infants.
• Data were analyzed in relation to gestational age and state (quiet vs. crying after vaccination).

Main Results:

• The S1/S2 ratio showed a decreasing trend with increasing gestational age, though not statistically significant.
• The D/S ratio significantly increased with advancing gestational age (p < 0.05).
• Following crying induced by vaccination, the D/S ratio significantly decreased compared to the quiet state across all gestational stages (p < 0.05).
• The CCCTS trended upwards with gestational weeks, but differences were not statistically significant.

Conclusions:

• Diastolic/systolic duration (D/S) is a sensitive indicator of cardiac reserve that changes with both gestational age and physiological stress in preterm infants.
• Phonocardiogram parameters like D/S can provide valuable insights into the developing cardiac function of preterm neonates.
• Further research may elucidate the clinical implications of these findings for preterm infant care.