Dear editor,

We read with much interest the paper of Owen et al on neonatal nasal intermittent positive pressure ventilation1. We are very thankful to the Authors for the citation of our work on BiPAP in preterm infants. However, we would like to point up that nasal (or nasopharyngeal) inspiratory positive pressure ventilation (NIPPV and NP-SIMV) is quite different from nasal bilevel (or biphasic) positive airway pressure (BiPAP). The NIPPV is a ventilation mode with similar characteristics of the IPPV applied in intubated patients. Peak inspiratory pressure (PIP) is obtained closing the expiratory valve of the circuit, preventing the patient’s expiration throughout the fixed inspiratory time (Ti). In BiPAP, PIP depends by the increase of gas flow into the circuit, allowing a completely free breathing on two CPAP levels. Support level is less “aggressive” than NIPPV, and side effects are lower; indeed, no gastrointestinal perforation or cerebral hemorrhage has ever been reported. Indications for use of the two type of ventilation are different. NIPPV can be preferred to ventilate apnoeic patients, while BiPAP always requires a spontaneous breathing (it has historically been used in COPD2 and CCHS3); it increases gas exchange modifying the minute ventilation by two different Functional Residual Capacities caused from the two CDP levels released by the ventilator. Moreover, if NIPPV is theoretically obtainable by any mechanical ventilator, for BiPAP specific devices are needed. This may explain the differences of PIP observed with some of the ventilators reported in the review. Non invasive ventilation is characterised by a “family” of techniques (CPAP, BiPAP, NIPPV, NP-SIMV, etc.) with different modalities and indications. We fully agree with the Authors that more research is necessary to define the applicability and the limits of each type of support.

References:

1) Owen LS, Morley CJ, Davis PG. Neonatal nasal intermittent positive pressure ventilation: what do we know in 2007? Arch Dis Child Fetal Neonatal Ed 2007;92;414-8.

2) Goldberg A, Leger P, Hill N, Criner G. Clinical indications for non- invasive positive pressure ventilation in chronic respiratory failure due to restrictive lung disease, COPD and nocturnal hypoventilation. A consensus conference report. Chest 1999;116:521-34.

3) Migliori C, Cavazza A, Motta M, Bottino R, Chirico G. Early use of “Bilevel Positive Airway Pressure” (BiPAP) ventilation in two infants with Congenital Central Hypoventilation Syndrome. Acta Paediatr 2003;92:823-6.