Maintaining Optimal HVNI Delivery Using Automatic Titration of Oxygen in Preterm Infants

Maintaining Optimal Delivery Using Automatic Titration of Oxygen in Preterm Infants Receiving High Velocity Nasal Insufflation Therapy

Oxygen treatment is common in management of preterm babies requiring intensive care. Delivery of too much or too little oxygen increase the risk of damage to eyes and lungs, and contributes to death and disability. Oxygen control in preterm infants requires frequent adjustments in the amount of oxygen delivered to the baby. This is generally performed manually by a clinician attending the baby, and generally directed to maintaining a specific range of blood oxygen saturation. The manual control often results in only half of the time in the specified range, with the baby experiencing high and low blood oxygen saturations.

The technology being studied is designed to assist the clinician in maintaining blood oxygen saturation within target range by measuring oxygen saturation and automatically adjusting the amount of oxygen delivered for babies receiving high velocity nasal insufflation (an advanced form of high flow oxygen therapy). The proposed study will evaluate the efficacy and safety of the automatic control of oxygen by the new technology, as compared to manual control, among babies receiving high velocity therapy in a neonatal intensive care unit.

Detailed Description: Supplemental oxygen is commonly administered to babies in neonatal intensive care units. The goal of oxygen therapy is to maintain normal oxygenation while minimizing hypoxemia and hypoxemia. Preterm infants are particularly vulnerable to oxygen toxicity and oxidative stress leading to retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), and periventricular leukomalacia (PVL). It's also well known that preterm infants experience hypoxic events exposing the baby to low oxygen levels. These hypoxic events vary as the infant matures, but exposure to prolonged and frequent episodes of hypoxemia is associated with increased morbidity and mortality. The delivery of oxygen is generally controlled by a clinician, and the control decisions are generally made using a non-invasive measure of blood oxygen saturation called pulse oximetry (SpO2) and is a standard of care in the neonatal intensive care unit. The most frequent item adjusted by clinicians to maintain SpO2 within specific target ranges is the fraction of the inspired oxygen (FiO2).

In a recent study by Reynolds, et al., caregiver manual control of oxygen delivered to NICU babies receiving high velocity therapy resulted in only 49% of the total 24-hour study period with the babies within the target SpO2 range (90-95%). by the caregiver based on the monitored oxygen saturation. Similar to the Reynolds findings, Hagadorn et al., conducted a study in 14 centers and showed that preterm infants under 28 weeks' gestation receiving oxygen spent on average only 48% of the time with SpO2 within the prescribed target range, about 36% of the time above and 16% of the time with SpO2 below the target range.

Preterm infants have frequent fluctuations in SpO2 due to their cardio-respiratory instability requiring frequent adjustments of FiO2 . Consequently, these particularly vulnerable infants spend significant time with SpO2 outside the optimal target range and are often exposed to extremes of hypoxemia and hyperoxaemia. The automatic oxygen control system continuously monitors the oxygen saturation and adjusts the oxygen delivery to maintain oxygen saturation within the target range. The efficacy of this mode of oxygen control was demonstrated by Reynolds, et al. in 2018 from two centers in the United Kingdom. Automated control of FiO2 can significantly improve compliance of oxygen saturation targeting and may significantly reduces exposure to hypoxemia as well as hyperoxaemia. The high velocity nasal insufflation therapy is a common mode of non-invasive respiratory support in preterm infants.

Unlike prior studies, this study will include a set of hypothesis-driven safety endpoints (proportion of time above or below target range), stratification by body mass at enrolment, and skin pigmentation phenotype. The objective of this randomized control trial is to evaluate the efficacy of the controller (Vapotherm Oxygen Assist Module [OAM]) in maintaining the SpO2 within target range for premature infants receiving high velocity therapy and presenting with a labile FiO2 requirement.

Inclusion Criteria:

1. Infants delivered at a gestational age of less than or equal to 35 6/7 weeks (Preterm) being treated with high velocity nasal insufflation therapy for the management of respiratory distress syndrome
2. Patients that clinically require SpO2 maintenance within the target range of 90-95%
3. A need for supplemental oxygen as demonstrated by a required FiO2 > 0.25 at enrollment
4. Requiring a flow rate of greater than 2 L•min-1 such that the assumed inspired oxygen fraction matched delivered oxygen fraction (definition of HVNI).
5. A minimum of 6 manual FiO2 adjustments in the 24hr period prior to trial enrollment.
6. Willing/Able to complete informed consent.

Exclusion Criteria:

1. Current patient weight of <1000g or >3500g at time of study
2. Major congenital abnormalities
3. Hemodynamic instability, defined as being outside of a normotensive range based on an infant's individual characteristics by clinician
4. Persistent unresolved apnea defined as: requiring 6 stimulations or more per 6 hours
5. Seizures
6. Ongoing sepsis
7. Meningitis
8. Clinician's concern regarding stability of the infant