Aafreen et al evaluate parameters measured in utero that can help to identify a neonate likely to develop respiratory distress. The authors are from Lady Hardinge Medical College in New Delhi.
Patient selection: pre-term neonate, from 28 to 34 weeks
Examination: prenatal ultrasound with Doppler parameters at or before 34 weeks
Parameters:
(1) acceleration time (At, time interval from ventricular systole to peak velocity) in seconds
(2) ejection time (Et, total time interval from ventricular systole to diastole), in seconds
(3) fetal lung volume
acceleration time to ejection time ratio =
= (At / Et)
lung volume in mL =
= ((area of left lung base in sq cm) + (area of right lung base in sq cm)) * 1/3 * (lung length in cm)
Parameter
Cut-Off for Respiratory Distress
Odds Ratio
At/Et ratio
< 0.3
7.5
fetal lung volume
< 15 mL
8.5
Cases of respiratory distress for both parameters were lower than the controls.
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