Effects of Non-invasive Ventilation With Helium-oxygen Mixture in Premature Infants With Respiratory Distress Syndrome

Effects of Non-invasive Ventilation With Helium-oxygen Mixture in Premature Infants With Respiratory Distress Syndrome on Pulmonary Function and Electric Activity of the Diaphragm

The use of a mixture of helium with oxygen (heliox) as a breathing gas may be beneficial due to its unique physical properties, such as low density and high carbon dioxide (CO2) diffusion coefficient. In previous studies in neonates with respiratory failure, conventional ventilation with heliox was associated with improved oxygenation and selected respiratory parameters. The use of heliox may increase the effectiveness of intermittent nasal positive pressure ventilation (NIPPV), but knowledge about the effects of such therapy on newborns is limited.The use of non- invasive neurally adjusted ventilatory assist (NIV-NAVA) allows synchronization and assessment of electrical activity of the diaphragm (EaDI) during heliox administration in premature babies with respiratory failure.

Aim of the study was to assess of the impact of non-invasive ventilation with heliox on respiratory function, diaphragm bioelectrical activity, cerebral oxygenation and selected vital signs in premature neonates with respiratory failure. 23 neonates ≤32 weeks gestational age (GA) were enrolled in the study. Patients were eligible for inclusion when ventilated due to respiratory failure, and in group 1 (n=12) on NIV as primary modality with oxygen requirement of 0.25-0.4 in the first 72 hours of life, or in group 2 (n=11) ready to extubate according to the given criteria. Newborns were ventilated with NIV NAVA and standard breathing gas (air-oxygen) at baseline. Heliox was introduced for 3 hours, followed by 3 hours of air-oxygen. NAVA level was kept constant and pulse oximeter oxygen saturation (SpO2) kept in range of 90-95%. Recorded parameters included heart rate (HR), SpO2 and cerebral tissue oxygenation (StO2). Selected ventilation parameters: peak inspiratory pressure (PIP), positive end-expiratory pressure (PEEP), mean airway pressure (MAP), air leakage during NIV, fraction of inspired oxygen (FiO2) as well as electrical activity of the diaphragm (EaDI mean, minimum and maximum) were also acquired. Blood gas analysis was performed in each period of the study. Statistical analysis was completed with ANOVA Friedman's test and single-factor repeated-measures analysis of variance.

Inclusion Criteria (Group 1):

• GA under 33 weeks GA
• Need for NIV due to clinical symptoms of respiratory distress in course of RDS
• FiO2=0.25-0.4
• Enrollment within first 72 hours of life
• Parental consent

Inclusion Criteria (Group 2):

• GA under 33 weeks GA
• Need for MV due to clinical symptoms of respiratory distress
• at least one failed attempted extubation
• Parental consent

Exclusion Criteria:

• Major congenital anomalies
• Deteriorating pulmonary function despite NIV and the need for intubation and conventional mechanical ventilation (CMV) (Preliminary criteria: pH< 7.22, carbon dioxide partial pressure (pCO2) >65)