ORIGINAL PAPER Vasiliki Kavvadia á Anne Greenough á Gabriel Dimitriou Effect on lung function of continuous positive airway pressure administered either by infant ¯ow driver or a single nasal prong Received: 29 June 1999 and in revised form: 23 September / Accepted: 15 October 1999 Abstract The aim of this study was to assess if continuous positive airways pressure (CPAP) delivered by an infant ¯ow driver (IFD) was a more eective method of im- proving lung function than delivering CPAP by a single nasal prong. A total of 36 infants (median gestational age 29 weeks, range 25±35 weeks) were studied, 12 who received CPAP via an IFD, 12 who received CPAP via a single nasal prong and 12 without CPAP. CPAP was administered post extubation if apnoeas and bradycardias or a respiratory acidosis developed or electively if the infant was of birth weight <1.0 kg. Lung function was assessed by the supplementary oxygen requirement and measurement of compliance of the respiratory system using an occlusion technique. Assessments were made imme- diately prior to and after 24 h of CPAP administration and at similar postnatal ages in the non-CPAP group. The infants who did not require CPAP had better lung function (non signi®cant) than the other two groups before they received CPAP. After 24 h, lung function had improved in both CPAP groups to the level of the non CPAP infants. The supplementary oxygen requirements of all three groups decreased over the 24 h period, but this only reached signi®cance in the single nasal prong group (P< 0.05). Four infants supported by the IFD, but none with a single nasal prong, became hyperoxic. Conclusion Continuous positive airways pressure administration via the infant ¯ow driver appears to oer no short-term advantage over a single nasal prong system when used after extubation in preterm infants. Key words Continuous positive airways pressure á Infant ¯ow driver á Lung function Abbreviations CPAP continuous positive airways pressure á CRS compliance of the respiratory system á FRC functional residual capacity á IFD infant ¯ow driver á NICU neonatal intensive care unit Introduction Continuous positive airways pressure (CPAP) is an in- creasingly popular form of respiratory support, used in the acute stage of respiratory distress syndrome [2, 10], following extubation [4, 13] and once apnoeas and bra- dycardias develop [7]. A variety of techniques have been used to deliver CPAP, but all have limitations. Recently a new nasal CPAP device has been designed [11]. In very low birth weight infants, the imposed work of breathing by this device was reported to be approximately 25% of that of a conventional device [9]. In addition, it showed less variability in the delivered airway pressure and was less sensitive to airway leakage [9]. We, therefore, Eur J Pediatr (2000) 159: 289±292 Ó Springer-Verlag 2000 V. Kavvadia á A. Greenough (&) á G. Dimitriou Children Nationwide Regional Neonatal Intensive Care Centre, King's College Hospital, London, UK e-mail: anne.greenough@kcl.ac.uk Tel.: +44-171-346-3037; Fax: +44-171-924-9365 A. Greenough Department of Child Health, King's College Hospital, London SE5 9RS, UK