Relationship Between Electrical Impedance Tomography (EIT) Measurements and Parameters of Respiratory Status in Very Preterm Infants: An Observational Cohort Study
Phase: NA
Conditions: Chronic Lung Disease of Prematurity, Bronchopulmonary Dysplasia, Premature Lungs
Sponsor: Lawrence Rhein

Study Protocol and Statistical Analysis 
Plan 
 
 
Official Title: Relationship Between Electrical Impedance Tomography (EIT) Measurements 
and Parameters of Respiratory Status in Very Preterm Infants: An Observational Cohort Study 
ClinicalTrials.gov Identifier: NCT06609135 
Sponsor: Lawrence Rhein 
Responsible Party: Lawrence Rhein, University of Massachusetts, Worcester 
Document Date: June 20, 2023 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

1. Study Overview  
This is a prospective, single-center, observational cohort study conducted at the UMASS 
Memorial Medical Center NICU. The study investigates the use of Electrical Impedance 
Tomography (EIT) to assess respiratory status in very preterm infants, and its potential predictive 
value for the successful discontinuation of respiratory support at key developmental timepoints.  
 
2. Study Design and Participants  
• Design: Prospective observational cohort  
• Setting: UMASS Memorial Medical Center NICU, Worcester, MA  
• Study Start: November 4, 2023  
• Completion Date: August 31, 2024  
• Enrollment: 20 infants 
 
Inclusion Criteria:  
• Infants born between 25+0 and 29+6 weeks gestational age  
• Admitted to UMass NICU 
 
Exclusion Criteria:  
• Major congenital anomalies  
• Severe hemodynamic instability  
 
3. Interventions and Devices  
• Device: Sentec LuMon Electrical Impedance Tomography (EIT) system  
• Device: Sentec Digital Monitoring System (transcutaneous CO₂ monitor)  
EIT and CO₂ monitoring were performed at least twice weekly, ideally daily, starting from 
consent through NICU discharge.  
 

4. Study Procedures  
EIT monitoring began at 28+0 weeks PMA or 7 days postnatally (whichever came later), and 
was repeated weekly until NICU discharge. Sessions lasted 3 hours and were timed between 
feedings to reduce motion artifacts. Data were stored securely after each session.  
 
5. EIT Metrics and Analysis 
EIT data were analyzed breath-by-breath to derive the following parameters:  
• FLS (Fraction of Lung Signal) – proxy for lung recruitment  
• GI (Global Inhomogeneity Index) – indicator of ventilation uniformity  
• CoV, EELI, and EILI were evaluated but not selected due to variability and artifacts GI was 
post-processed by Sentec; FLS was computed in-breath using standard software.  
 
6. Study Outcomes 
Primary Outcome  
• Association of FLS and GI at 31+0 weeks PMA with successful CPAP discontinuation at 32+0 
weeks PMA  
 
Secondary Outcomes  
1. Prediction of CPAP discontinuation at 33+0 weeks PMA based on EIT metrics at 32+0 weeks  
2. Association of metrics at 34+0 weeks PMA with CPAP independence by 36+0 weeks  
3. Exploratory:  
• Correlation between EIT and transcutaneous CO₂ levels  
• Correlation with time to full oral feeds  
• Association with BPD status at 36+0 weeks PMA  
 
7. Statistical Analysis Plan  
• T-tests for continuous variables (e.g., FLS, GI vs. CPAP outcomes)  

• Fisher’s exact tests for categorical demographic characteristics  
• Missing data were handled via complete case analysis  
• No imputation was applied 
• Sample size (n=20) limits power; analyses are considered exploratory  
 
8. Limitations  
• Missing data due to timing of enrollment and technical failures  
• Only 3/6 weaned infants and 8/14 non-weaned infants had usable data at 31 weeks  
• At 33 weeks: 4/14 missing; at 36 weeks: 3/10 missing  
• Measurement variability due to EIT belt placement, gel quality, motion, and interference  
• Small sample size limits statistical power and generalizability  
• Demographic imbalance (e.g., GA, weight) not controlled