(731) Estimation of Pleural Effusion Volume and De-Escalation of Respiratory Support Utilizing POCUS

Introduction: Ultrasound is utilized to qualitatively estimate the size of pleural effusion volume identified on chest radiography. Currently, the pediatric literature is devoid of investigations demonstrating the ultrasound's capacity to provide a quantitative estimation of pleural effusion volume. The primary objective of this study is to determine if POCUS can estimate pleural effusion volumes utilizing specific intrathoracic dimensions. The secondary objective of this study is to determine the volume of pleural effusion that must be removed to de-escalate respiratory support.

Methods: A total of 111 patients who underwent chest tube placement by interventional radiology were included in this study. Inclusion criteria included pediatric patients, pleural effusion on chest radiography and required chest tube placement. Linear regression analysis was performed to determine correlation between pleural distance normalized against patient height (cm) and pleural effusion volume obtained after drainage. 3D CT was utilized to determine total lung volume (mL). From this estimate, our group calculated the effusion volume (mL/kg) as a function of IBW (kg) to determine the volume of pleural effusion required to be removed to deescalate respiratory support. Statistical analysis was performed on Minitab Software 5.0.

Results: After linear regression analysis, there was a moderately strong correlation between pleural distance normalized against the patient’s height (cm) and the volume of pleural effusion drained, (y=252.9x + 43.3 R2= 0.55, R=0.72). Our group determined 5.1 +/- 1.7 mL/kg, (95% CI: 5.1 +/- 0.5) of pleural effusion volume was required to be drained in order to de-escalate respiratory support. 97% of patients underwent respiratory de-escalation after chest tube placement within 48 hours of intervention by interventional radiology.

Conclusions: This is the first pediatric investigation to determine if bedside ultrasound can utilize specific anatomical dimensions to quantitatively estimate pleural effusion volume in the critical care setting. The correlation identified in this study should be further investigated in a larger, prospective cohort to determine if POCUS can inform clinicians as to whether a patient should have pleural effusion drainage that will result in de-escalation of respiratory support.