PT  - JOURNAL ARTICLE
AU  - Cook, Shannon E
AU  - Fedor, Katherine L
AU  - Chatburn, Robert L
TI  - Effects of Imposed Resistance on Tidal Volume With 5 Neonatal Nasal Continuous Positive Airway Pressure Systems
DP  - 2010 May 01
TA  - Respiratory Care
PG  - 544--548
VI  - 55
IP  - 5
4099  - http://rc.rcjournal.com/content/55/5/544.short
4100  - http://rc.rcjournal.com/content/55/5/544.full
AB  - BACKGROUND: Neonates with respiratory distress syndrome are often treated with nasal continuous positive airway pressure (CPAP). Nasal CPAP methods include electronic feedback control, underwater seal, flow opposition, and flow opposition with fluidic flow reversal on expiration. Few studies have compared those modes, and the results have been contradictory. METHODS: We compared the effect of resistive load on simulated tidal volume (VT) with 5 neonatal nasal CPAP systems: Fisher and Paykel nasal CPAP tubing with Maquet Servo-i ventilator in NIV CPAP mode; Cardinal Health AirLife nasal CPAP system; Fisher and Paykel nasal CPAP tubing with water-seal pressure generator; AirLife infant nasal CPAP generator kit; and Hamilton Medical Arabella fluidic nasal CPAP generator. The lung simulator settings were: compliance 0.5 mL/cm H2O, resistance 125 H2O/L/s, sinusoidal patient-effort range 6.5–26 cm H2O, rise 25%, hold 0%, release 25%, respiratory rate 65 breaths/min. We compared the mean values from 10 breaths. RESULTS: The mean inspiratory pressure drop and VT difference (compared to the simulator alone, unloaded) increased with VT, respectively, from 0.32 cm H2O to 1.73 cm H2O, and from −0.04 mL to −0.40 mL. Flow opposition had the smallest pressure drop (from 0.10 cm H2O to 0.64 cm H2O, P < .001). At VT of ≤ 6 mL, the bubble nasal CPAP's pressure drop was largest (P < .001), whereas at VT of ≥ 9 mL the electronic nasal CPAP's pressure drop was largest (P < .001). All systems except the ventilator did not have an average end-expiratory pressure of the targeted 5 cm H2O. CONCLUSIONS: The differences in these nasal CPAP systems correlate with the differences in unassisted VT due to loading effects. The ventilator imposed the least load, and the AirLife nasal CPAP system imposed the most.