Correlation Analysis Between Fetal Lung Maturity and Cardiac Contractility Reserve of Premature Infants

Abstract

Objective To study the correlation between fetal lung maturity and cardiac contractility reserve(CCR) of premature infants. Methods A total of 36 cases of premature infants within 2 h after birth who were hospitalized delivery in West China Second University Hospital, Sichuan University from July 2008 to August 2009 were investigated in this study. Use foam test of amniotic fluid and amniotic fluid lamellar body count(LBC) to detect fetal lung maturity. According to the fetal lung maturity, they were divided into fetal lung immature group (n=17) ,fetal lung questionable mature group (n=3) and fetal lung mature group (n =16) . Use phonocardiogram test to measure CCR which included: first heart sound amplitude/ second heart sound amplitude (S1/ S2) , diastolic phase/ systolic phase (D/ S) and cardiac contractility change trend after stimulation(CCCTS) . The linear regression analysis was used to analyze the correlation between the fetal lung maturity and CCR of the premature infants. The study protocol was approved by the Ethical Review Board of Investigation in Human Beings of West China Second University Hospital, Sichuan University . Informed consent was obtained from the parents of each participating patient. The general statistics such as birth weight and length in each group had no significant difference (P>0.05) . Results The fetal lung maturity has positive correlation with the gestational age (r=0.536, P=0.001) . Compare S1/ S2 and CCCTS of three groups ,had no significant difference (H=0.013, 1.651, P>0.05) , while the D/ S of premature infants had significant difference between fetal lung immature group and fetal lung mature group (q=0.088, P=0.023) . The lung maturity had no correlation with the S1/ S2 and CCCTS (r=0.189 2, 0.289 0, P>0.05) ,and had positive correlation with the D/ S (r=0.401 4, P =0.017) . Conclusions The more mature the fetal lung is, the longer time for myocardial perfusion, and more oxygen or nutrition cardiac muscle get can make higher CCR of premature infants. It is necessary to strengthen the heart care for the premature infants, especially those with immature fetal lung. In addition, it showed through the father study about the correlation between D/ S and fetal lung maturity, maybe we could find a new way to test the fetal lung maturity. Key words: Cardiac contractility reserve; Myocardial contraction; Fetal organ maturity; Heart sounds; Infant, premature