P2.I175: Neonatal Noninvasive Ventilation Pressure Injuries: A Prospective Observational Benchtop Study

Background: Respiratory distress is a common complication of prematurity with an incidence of 6.7% overall and 30.0-65.6% within the preterm population. After the AAP strongly recommended the use of CPAP as an alternative to routine intubation, a rapid shift to noninvasive ventilation (NIV) occurred. Since most patients receive nasal CPAP, a concomitant, substantial increase in nasal pressure injuries occurred, reported in 30% of neonates overall and up to 100% of preterm neonates resulting in costs ranging from $890 to $98000 per patient. Initial attempts at quantifying pressure exerted by nasal masks on facial skin demonstrated pressures ranging from 6.46 to 158.25 mmHg. Studies have suggested that regular NIV placement training can reduce pressure injuries. The objectives of this prospective observational study are to develop clinical strategies to reduce nasal pressure injury in premature neonates by 1.) quantifying interface pressure between a commercial nasal CPAP interface and a neonatal simulator and 2.) assessing the pressure variation caused by inter-individual variability.

Methods: A calibrated 1F MEMS Connect pressure sensor (Millar®) was modified for contact measurements with silicone embedding. The sensor was calibrated prior to each experiment. A 24-Week Preterm Newborn Skills Trainer (Gaumard Scientific®) was used as a neonatal simulator. A bubble CPAP generator and interface components were sized for the simulator and assessed at 6 cmH20 and 8 L/min with no humidification. Thirteen University of Cincinnati Medical Center NICU staff comprised of registered nurses (n=6) and respiratory therapists (n=7) placed the simulator on CPAP at 6 cmH20 and 8 L/min with no humidification. Pressure was measured in triplicate at the forehead, nasal bridge, and nasal philtrum. Descriptive statistics and a location-specific, one-way analysis of variance (ANOVA) with a Tukey post hoc test were performed (Minitab, LLC).

Results: Pressure across all sites ranged from 12.3 to 377.3 mmHg (over 15x neonatal diastolic blood pressure). The mean (SD, 95% CI) interface pressure (mmHg) at the nasal philtrum was significantly higher than both the nasal bridge and the forehead (nasal philtrum: 173.9 (101.3, 152.0-195.9), nasal bridge: 67.79 (28.9, 45.86-89.73), and forehead 79.02 (36.87, 57.09-100.95), p ˂ 0.05) (Fig. 1). There was implementation variation of CPAP interface components, including bonnet placement, trunk angle, mask compression, use of hook and loop extenders, and level of vigorous bubble feedback achieved (Fig. 2).

Conclusion: The maximum pressures were higher than those previously reported in literature with the nasal septum significantly higher than both the nasal bridge and the forehead. Inter-individual variability was captured in both quantitative measurements and visual analysis of post-placement images. Small movements of the interface components or the neonatal simulator resulted in large changes in pressure, such that ideal placement could not be reasonably maintained. Improved NIV nasal mask interfaces should focus on stability and improved sizing increments.