Prospective Evaluation of the Correlation of Lung Ultrasonography Score and Blood Gas Parameters in Neonates With Respiratory Distress

Abstract

Introduction Lung ultrasonography (LUS) has become frequently used in neonatal intensive care units (NICU) because it is diagnostic, useful, harmless, radiation-free, and practical for bedside use due to its portability. Objective This study aimed to evaluate the association between lung ultrasound (LUS) scores and diagnoses of neonates hospitalized for respiratory distress and determine the value of the combined use of laboratory and imaging methods in patient evaluation by looking at the correlation between blood gas parameters and LUS score. Materials and methods Between March and July 2022, a total of 55 patients who were born term or premature and admitted due to respiratory distress in the NICU of Malatya Training and Research Hospital were included in the study. In this observational, prospective study, demographic information such as birth weights, gestational weeks, mode of delivery, Apgar scores, blood gas sample results, LUS results and scores, ventilation types, and discharge time were recorded during hospitalization in our unit. According to the newborns' clinical, laboratory, and radiologic evaluations, the diagnoses of respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN), or congenital pneumonia were made, and the relationship between the diagnoses and LUS scores was evaluated. The pH value and PCO2 value in the venous blood gas obtained on the day of LUS were recorded. Correlation analysis was performed between the LUS score and pH value, LUS score and PCO2 value. Results Twenty-seven newborns were diagnosed with TTN, 18 with RDS, and 10 with congenital pneumonia. There was a statistical difference between LUS scores and diagnoses (p<0.001). According to Spearman correlation analysis, a significant negative moderate correlation was found between LUS scores and venous blood gas pH value (p<0.001, r:-0.49). There was also a significant positive low, moderate correlation with venous blood gas PCO2 value (p<0.001, r:0.36). Conclusion This study demonstrates that LUS scoring has a role in determining the severity of disease and making diagnoses in patients hospitalized for respiratory distress. When LUS is widely used, it will be informative about the severity and prognosis of the disease, together with laboratory evaluation.

Keywords: blood gas sample; lung ultrasound; lung ultrasound score; newborn; respiratory distress.

Figure 1. Description of the LUS score.

Each lung has been divided into three areas, as shown in the upper part of the figure. For each area, a score of 0 to 3 has been assigned. Scores are given as follows, for any lung area: 0 indicates only A lines ( arrowheads); 1, defined as the presence of ≥3 B-lines (arrowheads); 2, severe B lines without consolidations (white lung) and 3, extended consolidation (box). LUS: Lung ultrasound.

Figure 2. Correlation of LUS score and pH.

LUS: Lung ultrasound.

Figure 3. Correlation of LUS score and PCO2.

LUS: Lung ultrasound.