The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts


Mitchell Goldstein1, Michael Terry1, Kate Gattuso1, Sunhwa Kim1, Elba Fayard1, Ricardo Peverini1

Background: Use of nasal ventilation in the NICU has increased over the past several years. Confusion has resulted from clinicians using varied nomenclature to refer to phasic nasal modes of ventilation in ways that differ from what may actually be delivered. In the common parlance, Nasal Intermittent Positive Pressure Ventilation (NIPPV) has been used to refer to ventilator Intermittent Mandatory Ventilation (IMV) supplied to the nasal apparatus. The question of whether this is a misnomer arises because the ventilator appears to be delivering a continuous positive pressure waveform unless the PEEP has been set to zero. We asked whether IMV via a nasal device results in a disruption of the continuous pressure waveform (NIPPV) or whether continuous pressure is present (NIMV).

Methods: Pediatric and infant (neonatal) nasal cannula (Salter Labs, Arvin, CA) adapted to an ETT adapter were pressurized with IMV breaths varying from 10/2 to 30/8 (PIP/PEEP). Continuous Distal flow was quantified by the presence of pressure propagation (flow) in a bubble chamber at varied depths during the entire phase of the ventilatory cycle. Pressures were analyzed graphically (Statistica 8, Statsoft, Tulsa, OK).

Results: As noted in the graphics below, continuous positive pressure was not consistently demonstrable at PEEP less than 3 cm H2O.

Conclusion: Higher resistances of CPAP devices may affect the pressure propagation at lower PEEP. Patient interface leak may also result in pressure loss. In these cases, pressure may be truly intermittent. NIMV can be differentiated by the presence of continuous pressure propagation during the ventilatory cycle. Nasal ventilation can be termed NIPPV only at lower PEEP in cannulae where continuous pressure is not maintained through the complete cycle.