Objective:

To establish the relationship between the gestational age and the maximum velocity of the ductus arteriosus (VmxDA), and to determine if it is possible to predict the fetal lung maturity with Doppler flow assessment of the VmxDA.

Study design:

A prospective, cohort study was conducted with non-probabilistic sampling where healthy patients who met the inclusion criteria were taken as a population. The maximum velocity of the ductus arteriosus was evaluated. Parametric values were estimated and the coefficient of regression and correlation, sensitivity and specificity was evaluated with gestational age. A 95% confidence interval was used, the different maximum ductus arteriosus velocities were obtained according to gestational age, and their respective standard error along with their standard deviations and they were correlated with gestational age, to determine the possibility of predicting lung maturity by flow assessment of the VmxDA.

Results:

824 patients were evaluated where it was evidenced an increase in the maximum velocity of the ductus arteriosus was observed as gestational age progressed. Two inflection points were found in the VmxDA curve at 28 weeks and at 35 weeks. A correlation coefficient of 0.97 was obtained with a probability level of less than 0.0001. The values of sensitivity and specificity to predict lung maturity were 83.9% and 100% for 95 cm / s and 91.5% and 100% for 98 cm / s, with a PPV of 0.709 and a NPV of 1.0. The interobserver variability was less than 5% for the VmxDA.

Conclusions:

There is a direct relationship between gestational age and the maximum velocity of the ductus arteriosus, which can be used as a good predictor of fetal lung maturity.

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