Premature infants commonly have desaturation episodes due to different reasons such as cessation of breathing or loss of lung volume. The purpose of this study is to differentiate the mechanisms of desaturation episodes with continuous lung volume monitoring. As we better understand the mechanisms underlying the desaturation episodes, newer strategies directed at underlying pathophysiology can potentially by evaluated for mitigation of these episodes.

This is an observational study evaluating changes in lung volume during hypoxemia episodes (HEs or desaturation episodes) in spontaneously breathing very preterm infants. We postulate that HEs can be differentiated into distinct subtypes based on alterations in lung volume. Additionally, the severity and duration of HEs correlates with the degree of changes in lung volumes. Therefore, we are performing an observational study in very preterm infants with spontaneous HEs and classifying these episodes into different subtypes of Apnea, forced exhalation, mixed, and unclassified subtypes according to changes in lung volume. Lung volume will be measured non-invasively using electrical impedance tomography (EIT) device (Sentec Inc, RI, USA). In brief, the device consists of a soft belt with 32 embedded electrodes which is placed around the chest of the infant and applies a weak alternating current and measures returning voltage. The measured returning voltage is dependent on the electrical conductivity of the underlying tissue. The reconstruction algorithm creates an image of regional impedance distribution in real time. These data are then used to compute lung volume parameters at different phases of respiratory cycle providing end expiratory lung impedance reflective of EELV, tidal impedance reflective of tidal volume, and regional distribution of ventilation. The changes in lung volume parameters will be used to differentiate HEs into different subtypes and correlated with degree and severity of HEs. In addition, we will also measure cerebral tissue oxygen saturation (CrSO2) to monitor changes in tissue oxygenation with hypoxemia episodes and changes in lung volume.

Inclusion Criteria:

• Born at ≤32w GA
• Post menstrual age between 30w to 36w
• 4 or more episodes of HEs in the previous 24h (Defined as SpO2<90≥5s)

Exclusion Criteria:

• Major congenital malformation
• Receiving invasive mechanical ventilation
• Severe neurological injury
• Hemodynamic instability requiring inotropes in last 72h

All infants admitted to the neonatal intensive care unit at Bristol Myers Squibb Children's Hospital and meeting eligibility criteria will be considered for enrollment and parents will be approached for informed consent.

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Beginning 9 months and ending 36 months following article publication

Researchers who provide a methodologically sound proposal and individual patient data meta-analysis.