126 - Relationship between lung ultrasound scores and echocardiographic measurements in very low birth weight infants

Lung ultrasound scores (LUS) are high in children with lung oedema. However, the effect of pulmonary overflow in very low birth weight infants (VLBWI) due to persistent ductus arteriosus (PDA) has never been studied. As infants born before 28 weeks have higher LUS, we hypothesize that LUS are less useful for this aim in this population.


Objective:

To describe the relationship between LUS and echocardiographic measurements related to PDA and left ventricular function in VLBWI.


Design/Methods:

We included all infants born before 32 weeks with an echocardiography and lung ultrasound performed on the same day (Echo-LU) from July 2018 until March 2022. We analyzed LUS; PDA parameters (transductal diameter, direction of shunt across ductus arteriosus, maximum systolic and diastolic velocities across the PDA, left pulmonary artery (LPA) end-diastolic and mean velocity, and left atrium/aortic valve annulus ratio (LA/Ao)); as well as left ventricular function measurements (mitral E and A waves, mitral E’, A’ and S’ velocities, mitral isovolumetric contraction and relaxation time, mitral ejection time and myocardial performance index).


Results:

We included 69 patients, that received 157 Echo-LU. The median GA was 28 weeks (interquartile rank (IQR) 26-29 weeks), median birth weight was 1000g (IQR 800-1250g). Twenty-one patients developed bronchopulmonary dysplasia (30%), and six died (9%).

In the whole sample, patients with left to right shunt had higher LUS (F=10.30, p< 0.001), and there was a significant correlation between LUS and PDA measurements: transductal diameter (r=0.14, p >0.001), peak systolic velocity (r=0.04, p=0.01), peak diastolic velocity (r=0.04, p=0.02), LPA end-diastolic velocity (r=0.14, p< 0.001), LPA mean velocity (r=0.14, p< 0.001) and LA/Ao (r=0.19, p< 0.001). Left ventricular function parameters were also correlated with LUS: both global (myocardial performance index, r=0.04 p=0.02) and diastolic measurements (mitral E’ velocity, r=0.04 p=0.02; isovolumetric relaxation time, r=0.08 p=0.01; mitral valve E/E’, r=0.05, p=0.01). And these results were similar if Echo-LU were performed in the first 7 days of life or latter.

However, the subgroup of 28 patients (41%) born before 28 weeks didn´t show higher LUS in case of left-to-right shunt, there was not a significant correlation between LUS and PDA measurements, neither with left ventricular disfunction parameters.


Conclusion(s):

LUS is correlated with echocardiographic PDA measurements, as well as with left ventricular function variables in VLBWI. However, this relationship is less clear in infants born before 28 weeks.