Surfactant Treatment Shows Higher Correlation Between Ventilator and EIT Tidal Volumes in an RDS Animal Model

Yoon Zi Kim; Hee Yoon Choi; Yong Sung Choi; Chae Young Kim; Young Joo Lee; Sung Hoon Chung

doi:10.3389/fphys.2022.814320

Surfactant Treatment Shows Higher Correlation Between Ventilator and EIT Tidal Volumes in an RDS Animal Model

Front Physiol. 2022 Apr 20:13:814320. doi: 10.3389/fphys.2022.814320. eCollection 2022.

Authors

Yoon Zi Kim¹, Hee Yoon Choi¹, Yong Sung Choi¹, Chae Young Kim¹, Young Joo Lee², Sung Hoon Chung¹

Affiliations

¹ Department of Pediatrics, College of Medicine Kyung Hee University, Seoul, South Korea.
² Department of Obstetrics and Gynecology, College of Medicine Kyung Hee University, Seoul, South Korea.

Abstract

Neonatal respiratory distress syndrome (RDS) is a condition of pulmonary surfactant insufficiency in the premature newborn. As such, artificial pulmonary surfactant administration is a key treatment. Despite continued improvement in the clinical outcomes of RDS, there are currently no established bedside tools to monitor whether pulmonary surfactant is effectively instilled throughout the lungs. Electrical impedance tomography (EIT) is an emerging technique in which physiological functions are monitored on the basis of temporal changes in conductivity of different tissues in the body. In this preliminary study, we aimed to assess how EIT tidal volumes correlate with ventilator tidal volumes in an RDS animal model, namely untreated, surfactant-treated, and normal control rabbit pups. Tidal volumes were measured simultaneously on an EIT system and a mechanical ventilator and compared at different peak inspiratory pressures. The linear correlation between tidal volumes measured by EIT and by ventilator had an R ² of 0.71, 0.76 and 0.86 in the untreated, surfactant-treated, and normal control groups, respectively. Bland-Altman analysis showed a good correlation between the measurements obtained with these two modalities. The intraclass correlation coefficients (ICC) between ventilator tidal volume and EIT tidal volume were 0.83, 0.87, and 0.93 (all p < 0.001) in the untreated, surfactant-treated, and normal control groups, respectively, indicating that the higher ICC value, the better inflated status of the lung. In conclusion, we demonstrated that EIT tidal volume correlated with ventilator tidal volume. ICC was higher in the surfactant treated group.

Keywords: alveoli collapse; electronic impedance tomography; homogeneity; mechanical ventilator; neonatal intensive care unit (NICU); premature infant; respiratory distress syndrome.