Modeling and characterization of gas coupled ultrasonic transducers at low pressures and temperatures and implications for sonic anemometry on Mars.

A sonic anemometer targeted at wind speed measurements on the surface of Mars is described. This environment requires transducer operation in 4-10 mbar CO2 at temperatures between 143 and 293 K (-130 °C and 20 °C, respectively). Over these ranges, transducer pressure and temperature sensitivity could be a source of measurement error. To investigate this, four candidate transducers were tested using transmission mode ultrasonic testing and impedance measurements: two narrowband piezoelectric transducers, a broadband capacitive transducer, and a micromachined capacitive ultrasound transducer. A system model was used for comparison and interpretation, and implications for a sonic anemometer were examined. Variation of transducer characteristics, including diffraction effects, across 2-10 mbar in CO2 and 190-293 K (-83 °C-20 °C) result in ±2.3% error in wind speed measurement and ±1.1% error in speed of sound measurement for the worst case but only ±0.14% error in wind and ±0.07% error in speed of sound for the best transducer operated off resonance. The acoustic conditions on Mars are similar to those in Earth's stratosphere at 30-42 km of altitude. Hence, testing was also conducted in dry air over the same range of pressures and temperatures with relevance to a secondary application of the instrument as a stratospheric anemometer for high altitude balloon missions on Earth.

Variability in Practice and Implementation of Oxygen Target Saturation Policies in United States' Neonatal Intensive Care Units.

OBJECTIVE: This study aimed to describe target oxygen saturation (SpO2) ranges used for premature infants in United States' neonatal intensive care units (NICUs) and to describe if these target SpO2 ranges have changed in recent years. STUDY DESIGN: A 29-question survey focused on target SpO2 practices and policies was distributed via the NICU medical directors listservs for the American Academy of Pediatrics Section of Neonatal-Perinatal Medicine and Pediatrix Medical Group between August and October of 2021. Results were collected via Research Electronic Data Capture (REDCap). RESULTS: We received responses representing 170 unique, levels 2, 3, and 4 NICUs from 36 states. Most NICUs (130, 78%) have recently changed their SpO2 targets in response to target SpO2 clinical trials. Over time, the most commonly reported target SpO2 range has shifted from 88-92% to 90-95. Of NICUs that changed limits, the most common lower SpO2 limits increased from 88 to 90% and the upper SpO2 limits changed from 92 to 95%. The interquartile range for lower SpO2 limit shifted from 85-88% to 88-90% and the IQR for upper SpO2 limit decreased from 92-95 to 94-95%. Most NICUs had designated conditions that would allow for deviations from standard target SpO2 ranges. These most commonly include pulmonary hypertension (152, 95%), severe bronchopulmonary dysplasia (81, 51%), and retinopathy of prematurity (51, 32%). CONCLUSION: Oxygen saturation limits have changed over time with an overall increase in targeted SpO2. However, there remains considerable interunit variation in SpO2 policies. There is a need to achieve consensus to optimize clinical outcomes. KEY POINTS: · What are the SpO2 ranges in United States' NICUs?. · There is a shift in SpO2 ranges for preterm infants in NICUs across United States.. · Variability still persists in SpO2 ranges for preterm infants in United States' NICUs..

Couplet Care-The Next Frontier of Care in the Newborn Intensive Care Unit.

Couplet care of mother and newborn intensive care unit (NICU) baby in the same room is a new, rapidly evolving option for the care of NICU babies. This change has structural and operational challenges that require careful planning but its successful implementation is likely to drive enhanced family participation in the care of their baby throughout the NICU stay as well as improve collaboration between obstetric and neonatal providers.