A Computer Controlled System to Simulate the Small, Rapid Oxygen Fluctuations Experienced by Preterm Infants Developing Retinopathy of Prematurity (ROP)

Abstract 85

Background: Preterm neonates experience small, frequent fluctuations in their blood oxygen values, which are associated with the development of severe ROP. Aims: To custom build equipment capable of reproducing the transcutaneous oxygen (TcPO₂) levels recorded by infant cotside monitoring equipment in a rat model. The equipment precision was assessed. Methods: Using previously published data for the rat that translates TcPO₂ into the equivalent inspired FiO₂, a profile was derived from a datalog of TcPO₂ values recorded every minute for 14 days in an infant that had developed severe ROP. This profile was controlled in the animal chamber by software algorithms which calculated the amount of gas to be injected to move oxygen to each new set-point. CO₂ regulation within the chamber was also possible. Results: Absolute differences between the datalog set-points (n = 17,465) and the oxygen sensor were median 0.3%, IQR 0.2 - 0.7%, with 95% of the differences < ±2%. Conclusion: The equipment is capable of reproducing the oxygen environment experienced by a preterm ventilated infant, giving a satisfactory level of precision.