Current evidence suggests that noninvasive positive pressure ventilation (NIPPV) is more effective than continuous positive airway pressure (CPAP) in preventing respiratory failure in preterm infants with respiratory distress syndrome (RDS), both as initial and post-extubation support. NIPPV may be delivered in synchronized (sNIPPV) or non-synchronized (nsNIPPV) modes, with sNIPPV offering clear benefits by coordinating support with the infant's own breathing. Recent studies indicate sNIPPV is superior to nsNIPPV in preventing respiratory failure, though the intrapulmonary mechanisms behind this advantage remain unclear. To address this, the present study uses Electrical Impedance Tomography (EIT) to evaluate how lung volume changes during different types of breaths and ventilator inflations - spontaneous breaths, synchronized inflations, non-synchronized inflations, and backup inflations - in preterm infants receiving sNIPPV.
Hypothesis: Synchronized inflations during NIPPV will increase tidal volumes (VT) and lung aeration when compared with non-synchronized inflations. Pressure peaks delivered during expiration (non-synchronized inflations), between spontaneous breaths (backup inflations), or during periods of apnea (backup inflations) will not increase relative VT. Primary objective: The primary objective is to assess lung volume changes between spontaneous breaths and synchronized inflations, non-synchronized inflations, and backup inflations using EIT. Secondary objectives: The secondary objectives are to assess regional differences in aeration and ventilation among spontaneous breaths, synchronized inflations, non-synchronized inflations, and backup inflations using EIT. Primary endpoint: Difference in relative Vt (rel. Delta-Z) between spontaneous breaths and synchronized inflations. Study procedures: Study procedures include attaching an EIT belt and a pulse oximeter sensor during the final nursing care session before the study begins. Synchronized NIPPV is provided by EVEneo ventilators, and synchronization will be achieved through an abdominal capsule (Graseby). 1. Sixty minutes after the beginning of the EIT recording , the noninvasve ventilation mode will be switched to CPAP for 2 minutes. This 2-minute period will be the baseline period during which spontaneous breathing will be assessed. 2. The NIV mode will then be switched back to sNIPPV. Ventilator settings will be maintained at the same levels used before the start of the study, and adjustments will not be permitted. 3. Prior to the next nursing care session, a second 2-minute nCPAP period will be introduced and serve as the baseline (together with the 1st CPAP period) . 4. The EIT recording and SpO2/HR measurements will continue until the next nursing care round, at which point the EIT belt and SpO2 sensor will be removed.
Study Type
OBSERVATIONAL
Enrollment
27
Electrical Impedance Tomography and clinical data will be recorded continuously. Corresponding data will be extracted and analyzed at five pre-defined timepoints.
University Hospital Zurich
Zurich, Canton of Zurich, Switzerland
RECRUITINGTidal volume (VT)
Difference in relative VT (rel. ΔZ) between spontaneous breaths and synchronized inflations.
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Global lung impedance
Difference between end-expiratory lung impedance (EELI) and inspiratory onset lung impedance (SILI) during spontaneous breaths, synchronized inflations, non-synchronized inflations, and back-up inflations.
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Regional tidal volume distribution
Difference in regional tidal distribution between spontaneous breaths, synchronized inflations, non-synchronized inflations and back-up inflations
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Center of ventilation
Difference in center of ventilation between spontaneous breaths, synchronized inflations, non-synchronized inflations and back-up inflations
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Silent spaces
Difference in silent spaces between spontaneous breaths, synchronized inflations, non-synchronized inflations and back-up inflations
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Global inhomogeneity index
Difference in global inhomogeneity index between spontaneous breaths, synchronized inflations, non-synchronized inflations and back-up inflations. An inhomogeneity index of zero represents a perfectly homogeneous distribution of ventilation.
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Coefficient of variation
Difference in coefficient of variation (EIT) between spontaneous breaths, synchronized inflations, non-synchronized inflations and back-up inflations
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Inspiratory time
Difference in inspiratory times between spontaneous breaths, synchronized inflations, non-synchronized inflations and back-up inflations
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Expiratory time
Difference in expiratory times between spontaneous breaths, synchronized inflations, non-synchronized inflations and back-up inflations
Time frame: At five pre-defined timepoints from the beginning to the end of the study at 180 minutes.
Lung ultrasound score
Difference in lung ultrasound score at two pre-defined timepoints. Each lung will be divided into 3 areas. For each lung area, a 0- to 3-point score will be given (total score ranging from 0-18). Higher scores represent greater severity of lung disease.
Time frame: Immediately before the first infant handling as well as following electrical impedance tomography belt removal.
Heart rate
Changes of heart rate between five pre-defined time points.
Time frame: Continuous measurement during the 180-minute recording period.
Peripheral oxygen saturation
Changes in oxygen saturation between five pre-defined time points.
Time frame: Continuous measurement during the 180-minute recording period.
Oxygen supplementation
Changes in FiO2 between five pre-defined time points.
Time frame: Continuous measurement during the 180-minute recording period.
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