An adult system versus a Bain system: Comparative ability to deliver minute ventilation to an infant lung model with pressure-limited ventilation

We compared the efficacy of an adult circle system versus a Bain system to deliver minute ventilation (V-E) to an infant test lung model using pressur e-limited ventilation. To simulate a wide variety of potential infant clini cal states, V-E was measured with two compliances: at peak inspiratory pres sures (PIP) of 20, 30, 40, and 50 cm H2O and at respiratory rates (RR) of 2 0, 30, 40, and 50 breaths/min. Each measurement was made three times, and t heir average was used for analysis. Data were analyzed using the multiple r egression technique. In both normal and low-compliance lung models, V-E was nearly identical between adult circle and Bain systems (P = 0.67 for norma l compliance model, P = 0.89 for low-compliance model). V-E positively corr elated with RR (P < 0.001), PLP (P < 0.001), and lung compliance (P < 0.001 ). Very high PIP or RR were required to deliver V-E to the low-compliance l ung model. The adult circle system is equivalent to the Bain system in its ability to ventilate an infant test lung over a wide range of RR, PIP, and two compliances during pressure-limited ventilation. V-E is dependent of PI P, RR, and lung compliance. With low-compliance lungs, both systems require a high PIP. We conclude that both anesthetic systems deliver ventilation o ver a wide range of respiratory variables during pressure-limited ventilati on in infants. Implications: We obtained results from this infant test lung study that indicate that either an adult circle breathing system or the Ba in system can reliably deliver ventilation over a wide range of respiratory variables during pressure-limited ventilation in infants.