Effect of Continuous Positive Airway Pressure Delivered by Two Different Modalities on Breathing Pattern in Preterm Infants

• The difference in the tonic EAdi between IF-CPAP and HFNC . [ Time Frame: During the 4-hour study period. ] [ Designated as safety issue: No ]
  Patients will be randomized in two groups, one group will start on IF-CPAP for 30 minutes. After another 45 minutes, this group will be switched to HFNC for another 30 minutes. The other group will start on HFNC and then switched to IF-CPAP. EAdi will be analyzed in the last 15 minutes of each 30 minutes period.
  
  

• Difference in the number of apnea episodes (breathing pauses) on EAdi recorded with each modality. [ Time Frame: During the 4-hour study period. ] [ Designated as safety issue: No ]
  
• Difference in episodes of clinically significant apnea with HFNC and IF-CPAP. [ Time Frame: During the 4-hour study period. ] [ Designated as safety issue: No ]
  
• Indices of respiratory muscle effort (inspiratory and expiratory) will be calculated from Edi waveform. [ Time Frame: During the 4-hour study period. ] [ Designated as safety issue: No ]
  These indices include the phasic Edi to the peak, mean inspiratory Edi, Edi-time product, post inspiratory activity and all neural timings.
  
  

Many preterm very low birth weight infants require continuous positive airway pressure(CPAP) for breathing support because of lung immaturity. CPAP can be delivered by the infant flow(TM) device which is well studied. Prolonged use of nasal prongs CPAP has been shown to cause discomfort and, rarely, nasal injury leading to long term disfigurement. On the other hand, High flow nasal cannula (HFNC) ,which is another modality of delivering CPAP, creates less pressure on the nose and less disfiguring effect but previous research showed that the use of HFNC may be less effective than IF-CPAP in providing breathing support in these infants.

We plan to study 10 stable preterm infants born less than 32 weeks' gestation and 1.5 kilograms at birth after being stable for at least 48hours on IF-CPAP. babies will be randomized to start on IF-CPAP or HFNC for 30 minutes. After 45 minutes of adaptation, baby will be switched to the other modality for another 30 minutes. By inserting a specialized feeding tube with sensors into the stomach, we can measure the electrical activity of the diaphragm (EAdi). By analysing EAdi with each modality of delivering CPAP, we want to directly assess how HFNC affects breathing compared to IF-CPAP.