Lung Volume Changes in Stable Preterm Infants Positioned in Car Seats (CarSeat)

Lung Volume Changes in Stable Preterm Infants Positioned in Car Seats - A Prospective Observational Study

Premature infants (infants born <37 weeks' gestational age) are discharged from the hospital and transported home in car seats designed for term babies. The safe transport of these premature infants is an important concern. Sub-optimal positioning in car seats can lead to breathing problems in premature infants. With the help of electrical impedance tomography, the investigators want to assess the changes in lung volume during the transition from a supine to a semi-upright position in the car seat.

Study Overview

• Status: Completed
• Conditions: Premature Birth; Electrical Impedance Tomography (EIT); Car Seat Transition for At-risk Infants; Lung Volume
• Intervention / Treatment: Device: Electrical Impedance Tomography

Detailed Description

Hypothesis The investigators hypothesise that there is a decrease in the end-expiratory lung volume (EELV) of preterm infants transferred from supine to car seat position. They expect that the curved, semi-upright built of a standard car seat negatively impacts lung aeration and ventilation of preterm infants, which may result in cardiorespiratory events. They also hypothesise that EELV will normalise following the repositioning of the infant back to the supine position.

Primary objective The primary objective of this study is to assess lung volume changes during the transition from a supine to a semi-upright position in a car seat in preterm infants.

Study procedures As soon as all inclusion criteria are met, the study intervention is initiated. For the baseline measurement, the child is placed in supine position on a flat surface. The EIT belt is attached at nipple level around the infant's thorax during the last nursing care before the start of the intervention. Continuous measurement is conducted for 30 minutes.

Subsequently, the child, with the EIT belt securely in place, is repositioned from a supine to a semi-upright position in a car seat, where another 30-minute measurement is taken. A third measurement will be conducted after the infant is returned to the standard supine position in his/her cot. Manipulations during the measurement periods will be kept to a minimum to avoid disruptions or artefacts in the data recordings. EIT data will be obtained for a total of 90 minutes (plus a maximum of 10 minutes for repositioning).

Subgroup analyses will be performed for the primary outcome:

• Preterm infants ≥ 32 versus < 32 weeks at birth
• Infants with a weight ≥ 2 kg versus < 2 kg at the time of the study
• Car seat positioning: nursing staff versus parents

• Study Type: Observational
• Enrollment (Actual): 51

Contacts and Locations

Study Locations

• Switzerland
  • Canton of Zurich
    • Zurich, Canton of Zurich, Switzerland, 8091
      • University Hospital Zurich

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This study will take place at the Department of Neonatology of the University Hospital Zurich. Preterm infants ready for discharge will be screened for eligibility and parents will be approached by the treating physician or a clinician-researcher who is authorized to access the patient's clinical data.

Description

Inclusion Criteria:

• Gestational age up to 36 6/7 weeks at birth and/or birthweight < 2.5 kg
• Preterm born infants fulfilling all criteria for discharge from the NICU
• Discharge home planned within 48 hours
• Written informed consent by one or both parents or legal guardians as documented by signature.

Exclusion Criteria:

• Severe malformation adversely affecting lung aeration or malformations limiting life expectancy.
• Inability of the parents to understand the study procedures due to cognitive or linguistic reasons.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Preterm infants < 37 weeks gestation at birth or birthweight <2.5 kg (within 48 hours of discharge); Preterm infants with gestational age up to 36 6/7 weeks at birth and/or birthweight < 2.5 kg will be included. They must fulfill all criteria for discharge from the Neonatal Intensive Care Unit and be discharged home within 48 hours at the time of measurement.	Device: Electrical Impedance Tomography; Electrical Impedance Tomography data and the physiological and clinical parameters will be recorded continuously in three different positions (supine 1, car seat, supine 2) to assess alterations in lung volume and cardiorespiratory events.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Global end-expiratory lung impedance	Changes in global end-expiratory lung impedance (EELZ) between a baseline measurement in supine position, measurement in a semi-upright car seat position, and a follow-up measurement back in a supine position, as a measure of lung aeration and a proxy for end-expiratory lung volume (∆EELZ = EELZCarSeat - EELZBaseline).	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Heart rate	Changes of heart rate between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Number of bradycardia	Changes in the number of bradycardia (heart rate < 80 bpm) between a baseline measurement in supine position, measurement in a semi-upright car seat position, and a follow-up measurement back in a supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Respiratory rate	Changes in respiratory rate between baseline, a semi-upright car seat position, and a follow-up supine position based on EIT data.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Oxygen Saturation	Changes in oxygen saturation between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Number of desaturations	Changes in the number of desaturations (SpO2 < 80%) between a baseline measurement in supine position, measurement in a semi-upright car seat position, and a follow-up measurement back in a supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Regional end-expiratory lung impedance	Changes in regional end-expiratory lung impedance between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Tidal Volume	Changes in tidal volume using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Respiratory minute volume	Changes in respiratory minute volume using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Regional tidal volume distribution	Changes in regional tidal distribution using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Silent spaces, depenent	Changes in dependent silent spaces using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Silent spaces, nondependent	Changes in nondependent silent spaces using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Center of ventilation, ventral to dorsal	Changes in center of ventilation (ventral to dorsal) using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Center of ventilation, left to right	Changes in center of ventilation (left to right) using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Global inhomogeneity index	Changes in global inhomogeneity index using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.
Coefficient of variation	Changes in coefficient of variation using EIT between baseline, a semi-upright car seat position, and a follow-up supine position.	Continuous measurement is conducted for 30 minutes in a supine position, 30 minutes in a semi-upright car seat position and an additional 30 minutes in a supine position. Total measurement of 90 minutes.

Collaborators and Investigators

• Sponsor: University of Zurich
• Investigators: Study Chair: Dirk Bassler, Prof., Newborn Research, Department of Neonatology, University Hospital and University of Zurich, Zurich, Switzerland

Study record dates

Study Major Dates

• Study Start (Actual): January 3, 2025
• Primary Completion (Actual): August 22, 2025
• Study Completion (Actual): August 22, 2025

Study Registration Dates

• First Submitted: December 4, 2024
• First Submitted That Met QC Criteria: December 4, 2024
• First Posted (Actual): December 9, 2024

Study Record Updates

• Last Update Posted (Actual): September 22, 2025
• Last Update Submitted That Met QC Criteria: September 16, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: premature birth; electrical impedance tomography; car seat
• Additional Relevant MeSH Terms: Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Obstetric Labor, Premature; Obstetric Labor Complications; Pregnancy Complications; Premature Birth
• Other Study ID Numbers: CarSeat

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No