Diaphragm Electrical Activity of Preterm Infants on nCPAP Versus NIHFV

Continuous Positive Airway Pressure is one of the most researched and accepted methods of delivering NIV to term and preterm infants. Non-invasive high frequency ventilation is a relatively new method of delivering NIV respiratory support in preterm infants. Preliminary studies suggest superiority over CPAP, and NIHFV is being increasingly utilized in clinical practice in an attempt to prevent intubation and minimize ventilation-induced lung injury in preterm infants. However, little is known about its mechanism of action and its effect on respiratory mechanics in the newborn. The objective of this study is to compare the effects of non-invasive ventilation (NIV) delivered by nasal Continuous Positive Airway Pressure (nCPAP) versus Non-Invasive High Frequency Ventilation (NIHFV) on respiratory pattern as assessed by the electrical activity of the diaphragm (EAdi) in very low birth weight (VLBW) preterm infants.

We hypothesize that in VLBW preterm infants with relative pulmonary insufficiency, NIHFV will reduce respiratory drive and improve ventilation, subsequently resulting in decreased patient diaphragm energy expenditure. This would be demonstrated by decreased neural respiratory rates and/or decreased peak electrical activity of the diaphragm while breathing on NIHFV compared to nCPAP.

Clinicians are seeking alternative methods for providing non-invasive respiratory support to preterm infants. NIHFV is a relatively new modality that is being increasingly utilized in clinical practice but has not been well studied. This study will help us determine how non-invasive high frequency ventilation (NIHFV) affects breathing in preterm infants, as compared to the more traditional modality of nasal CPAP. Therefore, clinicians will not only be able to better understand how NIHFV works, but also utilize this information to decide on the most appropriate respiratory support modality for preterm patients

Inclusion criteria

• Clinically stable preterm infants with birth weights ≤1500g admitted to the neonatal intensive care unit (NICU) at Sunnybrook Health Sciences Centre or BC Women's and Children's Hospital.
• Patient's on nasal continuous positive airway pressure of 6 to 8 cmH20 support for at least 48 hours, treated with methylxanthines for apnea of prematurity and requiring 25-40% of oxygen.

Exclusion criteria

• infants with congenital anomalies of the gastrointestinal tract, phrenic nerve damage, diaphragmatic paralysis, esophageal perforation;
• infants with congenital or acquired neurological deficit (including significant intraventricular hemorrhage >Grade II) [27], neonatal seizure;
• infants with significant congenital heart disease (including symptomatic PDA);
• infant with congenital anomalies of the diaphragm;
• infant with congenital anomalies of the respiratory tracts (e.g. Congenital Cystic Adenomatoid Malformation (CCAM)) infants requiring ongoing treatment for sepsis, necrotizing enterocolitis (NEC), antibiotics for lung infections, narcotic analgesics, or gastric motility agents will be excluded.
• infants on nasal CPAP and requiring more than 40% oxygen will be excluded from the study.
• infants with significant gastric residuals and vomiting, infants with facial anomalies, infants with pneumothorax or pneumomediastinum, and infants in the immediate postoperative period will be excluded.