Continuous positive airway pressure (CPAP) is a noninvasive, continuous flow respiratory system that maintains positive pressure in the infant’s airway during spontaneous breathing. CPAP was developed by George A. Gregory, in the late 1960s (1). Positive pressure was originally applied by placing the neonate’s head into a semi-airtight “box” (the Gregory box) and, subsequently, by a fitted face mask covering the mouth and nose (2). A major problem with both these methods of application was the fact that it was difficult to feed the baby without discontinuing the CPAP; thus, the evolution to the current method of applying CPAP through bilateral nasal prongs (3). “Bubble CPAP” (b-CPAP) is a modern resurgence of the original method of supplying CPAP, wherein pressure is generated in the breathing circuit by immersing the distal end of the expiratory limb of the breathing circuit under water seal (Fig. 37.1) (4, 5, 6).

b-CPAP allows provision of CPAP without use of a ventilator, and is currently primarily used for early treatment of low-birthweight premature infants, with or at risk for, respiratory distress syndrome and/or with frequent apnea/bradycardia (7). In addition to cost considerations, there is early evidence that b-CPAP may be more effective in small premature babies than ventilator-derived CPAP (8).