Feasibility and Impact of Volume Targeted Ventilation for Preterm Infants Born <32 Weeks Gestational Age With Need for Invasive Positive Pressure Ventilation in the Delivery Room in Reducing Neonatal Pulmonary Morbidities

BACKGROUND BPD continues to be one of the most common complications associated with preterm birth. A 2013 US study reported an increase in healthcare cost of $31,565 associated with BPD, after controlling for birth weight, gestational age, and socio-demographic characteristics during the initial neonatal intensive care unit (NICU) hospitalization itself. This economic burden starts from the initial NICU admission and persists through childhood and adulthood. A recent Spanish study published in 2013, reported that the healthcare related cost during the first 2 years of life of a preterm baby with BPD and no other major prematurity-related complications ranged between €45,049.81 and €118,760.43, in Spain, depending on birth weight and gestational age. If the baby required home oxygen therapy or developed pulmonary hypertension, this cost could further escalate to €181,742.43. With 10,000-15,000 new cases of BPD annually in USA alone, the economic impact of BPD is tremendous.

The pathogenesis of BPD is multifactorial, with lung injury from mechanical ventilation, oxygen toxicity, and antenatal or postnatal infections, all leading to lung inflammation which play a key role in the development of BPD. Delivery room (DR) management of preterm infants during the initial resuscitation is critical, and can have a significant impact on development of BPD. Studies have demonstrated that DR respiratory management with invasive respiratory support and higher oxygen content is associated with increased risk of death and/or BPD compared to non-invasive ventilation and lower oxygen resuscitation, respectively. Preterm infants stabilized on continuous positive airway pressure (CPAP) with prudent titration of supplemental oxygen in the delivery room to achieve targeted oxygen saturations have demonstrated improved rates of BPD.

CURRENT STANDARD OF PRACTICE Current DR practice for intubated preterm infants focuses on pressure limited ventilation using either a self-inflating bag or a T-piece resuscitator where the provider regulates the inflation pressure and inflation time, but not the tidal volume.

As an infant transitions to extra uterine life, pulmonary compliance changes rapidly. Total pulmonary compliance is a composite of the lung and chest wall compliances. In preterm infants, the chest wall is composed primarily of cartilage rendering the chest wall highly compliant, and as a result, the neonatal lung is more prone to collapse. Preterm lungs additionally have reduced surfactant production which further decreases lung compliance. Upon initiation of positive pressure ventilation (PPV), the rapid fluid shift in the immediate newborn period can also result in swift changes in a newborn's pulmonary compliance. Provision of maternal antenatal steroids as well as surfactant replacement therapies can positively impact the preterm pulmonary outcomes. For these preterm infants, tidal volumes generated during PPV is directly proportional to the lung compliance as demonstrated by the formula: Cdyn=VT/(PiP-PEEP), where, VT = tidal volume; PIP=peak inspiratory pressure; and PEEP=positive end-expiratory pressure.

Hence, with PLV the exact same pressure due to rapidly changing lung compliance may lead to under-inflation or over-inflation of the lungs.