Characterization of lung ultrasound imaging in preterm infants with bronchopulmonary dysplasia

Effects of Lung Ultrasound Technique and Pleural Line Depth on In Vitro and In Vivo Measurements of Pleural Line Thickness

OBJECTIVE

The aim of the work described here was to determine the effects of imaging protocol, technique and pleural line depth on measured pleural line thickness (PLT).

METHODS

Sonograms were performed on a phantom and healthy volunteers. In vitro, pleural line depth, transducer type (5-1 MHz phased array vs. 13-6 MHz linear array), angle of the pleural line relative to the transducer and distance between the pleural line and focal length were explicitly modified. PLT was measured using electronic calipers. Regression equations described the effects of independent variables on PLT. Factors influencing PLT in vitro were tested in vivo.

RESULTS

In vitro (n = 250 sonograms), PLT was 3.8 (standard error: ±0.24) mm greater when using the phased array compared with the linear transducer (p < 0.001). For every additional centimeter of pleural line depth, PLT increased by 0.96 (±0.081) mm for the phased array (p < 0.001) and 0.26 (±0.019) mm for the linear transducer (p < 0.001). Neither pleural angle nor focal length altered PLT. In vivo (n = 160 sonograms), PLT was 2.56 (±0.06) mm greater when using the phased array (p < 0.001) compared with the linear transducer. PLT increased by 0.67 (±0.060) mm with the phased array (p < 0.001) and 0.25 mm (±0.019) with the linear transducer (p < 0.001) for every additional centimeter between the transducer and the pleura. Together the variables explained 93% of PLT variance in vivo (p < 0.001).

CONCLUSION

PLT measurements are affected by transducer type and pleural line depth. Future studies evaluating PLT as a disease marker should account for confounding by these variables.

Imaging of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a multifactorial disease with many associated co-morbidities, responsible for most cases of chronic lung disease in childhood. The use of imaging exams is pivotal for the clinical care of BPD and the identification of candidates for experimental therapies and a closer follow-up. Imaging is also useful to improve communication with the family and objectively evaluate the clinical evolution of the patient's disease. BPD imaging has been classically performed using only chest X-rays, but several modern techniques are currently available, such as lung ultrasound, thoracic tomography, magnetic resonance imaging and electrical impedance tomography. These techniques are more accurate and provide clinically meaningful information. We reviewed the most recent evidence published in the last five years regarding these techniques and analyzed their advantages and disadvantages.

Prediction of respiratory distress severity and bronchopulmonary dysplasia by lung ultrasounds and transthoracic electrical bioimpedance

This study aims to evaluate whether the assessment of a lung ultrasound score (LUS) by lung ultrasonography and of thoracic fluid contents (TFC) by electrical cardiometry may predict RDS severity and the development of bronchopulmonary dysplasia (BPD) in preterm infants with respiratory distress (RDS). Infants ≤ 34 weeks' gestation admitted with RDS to two neonatal intensive care units were prospectively enrolled in this observational study. A simultaneous evaluation of LUS and TFC was performed during the first 72 h. The predictivity of LUS and TFC towards mechanical ventilation (MV) need after 24 h and BPD development was evaluated using receiver operating characteristic analysis. Sixty-four infants were included. The area under the curve (AUC) for the prediction of MV need was 0.851 (95%CI, 0.776-0.925, p < 0.001) for LUS and 0.793 (95%CI, 0.724-0.862, p < 0.001) for TFC, while an AUC of 0.876 (95%CI, 0.807-0.946, p < 0.001) was obtained for combined LUS and TFC evaluation. LUS and TFC AUC for BPD prediction were 0.769 (95%CI, 0.697-0.842, p < 0.001) and 0.836 (95%CI, 0.778-0.894, p < 0.001), respectively, whereas their combined assessment yielded an AUC of 0.867 (95%CI, 0.814-0.919, p < 0.001). LUS ≥ 11 and TFC ≥ 40 were identified as cut-off values for MV need prediction, whereas LUS ≥ 9 and TFC ≥ 41.4 best predicted BPD development.   Conclusion: A combined evaluation of LUS and TFC by lung ultrasonography and EC during the first 72 h may represent a useful predictive tool towards short- and medium-term pulmonary outcomes in preterm infants with RDS. What is Known: • Lung ultrasonography is largely used in neonatal intensive care and can contribute to RDS diagnosis in preterm infants. • Little is known on the diagnostic and predictive role of TFC, measured by transthoracic electrical bioimpedance, in neonatal RDS. What is New: • Combining lung ultrasonography and TFC evaluation during the first 72 h can improve the prediction of RDS severity and BPD development in preterm infants with RDS and may aid to establish tailored respiratory approaches to improve these outcomes.

A scoping review of echocardiographic and lung ultrasound biomarkers of bronchopulmonary dysplasia in preterm infants

Despite recent improvements in neonatal care, moderate to severe bronchopulmonary dysplasia (BPD) is still associated with high mortality and with an increased risk of developing pulmonary hypertension (PH). This scoping review provides an updated overview of echocardiographic and lung ultrasound biomarkers associated with BPD and PH, and the parameters that may prognosticate their development and severity, which could be clinically helpful to undertake preventive strategies. A literature search for published clinical studies was conducted in PubMed using MeSH terms, free-text words, and their combinations obtained through appropriate Boolean operators. It was found that the echocardiography biomarkers for BPD, and especially those assessing right ventricular function, are reflective of the high pulmonary vascular resistance and PH, indicating a strong interplay between heart and lung pathophysiology; however, early assessment (e.g., during the first 1-2 weeks of life) may not successfully predict later BPD development. Lung ultrasound indicating poor lung aeration at day 7 after birth has been reported to be highly predictive of later development of BPD at 36 weeks' postmenstrual age. Evidence of PH in BPD infants increases risk of mortality and long-term PH; hence, routine PH surveillance in all at risk preterm infants at 36 weeks, including an echocardiographic assessment, may provide useful information. Progress has been made in identifying the echocardiographic parameters on day 7 and 14 to predict later development of pulmonary hypertension. More studies on sonographic markers, and especially on echocardiographic parameters, are needed for the validation of the currently proposed parameters and the timing of assessment before recommendations can be made for the routine clinical practice.

A bedside ultrasound protocol to the measurement of the systemic vascular resistances: Preliminary results in the patients with sepsis

BACKGROUND

The use of the ultrasound (US) bedside examination is increasing for the detailed evaluation of the hemodynamic parameters, allowing the physicians to set the appropriate therapeutic strategies with greater precision.

OBJECTIVE

The aim of this study is to evaluate the hemodynamic parameters (the cardiac output or CO, the central venous pressure or CVP and the systemic vascular resistance or SVR) in the patients with sepsis, by using a bedside US approach.

METHODS

We consecutively enrolled n.82 patients of S.Andrea Hospital (n.47 with sepsis and n.35 without sepsis), examining the hemodynamic parameters by a bedside US evaluation.

RESULTS

The incidence of sepsis was more than 50% of cases. The patients with sepsis presented higher comorbidity and polypharmacy (p < 0.01, p < 0.001), with increased creatinine (p < 0.001) and consequent esteemed glomerular filtration rate (p < 0.01), C-reactive protein (p < 0.01), SOFA (Sepsis-related Organ Failure Assessment) score (p < 1.58×10-7) and reduced SVR (p < 0.05). The SOFA score was inversely related to the SVR (p < 0.05).

CONCLUSIONS

To our best knowledge, this is the first study with a bedside US protocol to measure SVR, beyond the abdominal and cardiac qualitative evaluation.

Application of ultrasonography in neonatal lung disease: An updated review

Lung disease is often life-threatening for both preterm and term newborns. Therefore, an accurate and rapid diagnosis of lung diseases in newborns is crucial, as management strategies differ with different etiologies. To reduce the risk of radiation exposure derived from the conventionally used chest x-ray as well as computed tomography scans, lung ultrasonography (LUS) has been introduced in clinical practice to identify and differentiate neonatal lung diseases because of its radiation-free characteristic, convenience, high accuracy, and low cost. In recent years, it has been proved that LUS exhibits high sensitivity and specificity for identifying various neonatal lung diseases. Here, we offer an updated review of the applications of LUS in neonatal lung diseases based on the reports published in recent years (2017 to present).