title: A Fixed Flow is More Effective than Titrated Flow during Bubble Nasal CPAP for Respiratory Distress in Preterm Neonates.
abstract: BACKGROUND
  The clinical effects of a pre-fixed flow of air-oxygen versus a flow titrated according to visible bubbling are not well understood.
  
  
  OBJECTIVE
  To compare the effects of a fixed flow (5 L/min) and titrated flow (flow just enough to ensure bubbling) at different set pressures on delivered intra-prong pressure, gas exchange and clinical parameters in preterm infants on bubble CPAP for respiratory distress.
  
  
  METHODS
  Preterm infants <35 weeks gestational age on bubble CPAP and <96 h of age were enrolled in this crossover study. They were subjected to 30-min periods of titrated flow and fixed flow. At the end of both epochs, gas flow rate, set pressure, FiO2, SpO2, Silverman retraction score, respiratory rate, abdominal girth, and blood gases were recorded. The delivered intra-prong pressure was measured by an electronic manometer.
  
  
  RESULTS
  69 recordings were made in 54 infants. For each of the set CPAP pressures (4, 5, and 6 cm H2O), the mean delivered pressure with a fixed flow of 5 L/min was higher than that delivered by the titrated flow. During the fixed flow epoch, the delivered pressure was closer to and higher than the set pressure resulting in higher PaO2 and lower PaCO2 as compared to titrated flow epoch. In the titrated flow period, the delivered pressure was consistently lower than the set pressure.
  
  
  CONCLUSIONS
  In preterm infants on bubble CPAP with set pressures of 4-6 cm H2O, a fixed flow of 5 L/min is more effective than a flow titrated to ensure adequate visible bubbling. It achieves higher delivered pressures, better oxygenation and ventilation.
authors.affiliation: Neonatal Unit, Department of Pediatrics, Fernandez Hospital , Hyderabad , India.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Murki
authors.affiliation: Neonatal Unit, Department of Pediatrics, Fernandez Hospital , Hyderabad , India.
authors.forename: Ratan Kumar
authors.initials: RK
authors.lastname: Das
authors.affiliation: Neonatal Unit, Department of Pediatrics, Fernandez Hospital , Hyderabad , India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Sharma
authors.affiliation: Neonatal Unit, Department of Pediatrics, Advanced Pediatrics Center, Postgraduate Institute of Medical Education and Research , Chandigarh , India.
authors.forename: Praveen
authors.initials: P
authors.lastname: Kumar
keywords: bubble CPAP; fixed flow; preterm; respiratory distress; titrated flow