We compliment Kaur, et al.(1) for bringing up the focus on the utility of CPAP in preterm neonates with respiratory distress. The indigenous CPAP circuit depicted in this article was first described by Gregory, et al.(2) and has been used all around the world including Indian neonatal units for more than three decades. However, while trying to bring down the costs of any equipment, compromising on the safety features can be counter-productive.

This circuit has its limitations. Application of CPAP to a neonate includes not only providing stable pressure, but also warm (at 37ºC) and humidified (100% relative humidity) oxygen at desired FiO2. This can not be achieved with this simple circuit. An efficient and effective humidifier costs at least Rs. 20,000. Also, if a heated wire is not present in the circuit, it leads to condensation, fluctuations in delivered pressure and increased risk of infection. Incompletely humidified or warmed gas leads to excessive excoriation of nostrils and nasopharynx.

Although FiO2 has been calculated and expected values tabulated previously by others, as has been done by the authors of this paper, in real life, the measured FiO2 is different from the calculated values. This is because the delivered FiO2 depends on many other factors like pressure in the gas chambers, circuit compliance, precision of flow meter etc., apart from the relative air and oxygen flow rates. Hence, though one may manage without an expensive blender; in lieu, a FiO2 monitor is a must and it costs between Rs. 15,000 to 25,000. We would disagree with the authors that bubbling CPAP can be safely used without having a pulse oximeter. The upper oxygen saturation limit in preterm babies should not be allowed to exceed 95% because of the potential risk of retinopathy of prematurity and hyperoxemia.

The first principle of any therapy has to be Primum non nocere. Therefore, one has to keep the limitations and potential dangers of this simple circuit described by Gregory in mind and strive to provide optimal CPAP even though at a higher cost. An efficient humidifier and a pulse oximeter have to be integral part of any CPAP system for neonates.