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In this case report, we are the first to describe the occurrence of a pneumothorax after ultrasound-guided supraclavicular block. The block was performed using a medial-to-lateral in-plane needle insertion technique. The predisposing operator, technical, and patient factors as well as strategies for preventing this uncommon yet potentially severe complication are discussed.

Vinyl cyanide (C 2 H 3 CN) is theorized to form in Titan's atmosphere via high-altitude photochemistry and is of interest regarding the astrobiology of cold planetary surfaces due to its predicted ability to form cell membrane-like structures (azotosomes) in liquid methane. In this work, we follow up on the initial spectroscopic detection of C 2 H 3 CN on Titan by Palmer et al. (2017) with the detection of three new C 2 H 3 CN rotational emission lines at submillimeter frequencies. These new, high-resolution detections have allowed for the first spatial distribution mapping of C 2 H 3 CN on Titan. We present simultaneous observations of C 2 H 5 CN, HC 3 N, and CH 3 CN emission, and obtain the first (tentative) detection of C 3 H 8 (propane) at radio wavelengths. We present disk-averaged vertical abundance profiles, two-dimensional spatial maps, and latitudinal flux profiles for the observed nitriles. Similarly to HC 3 N and C 2 H 5 CN, which are theorized to be short-lived in Titan's atmosphere, C 2 H 3 CN is most abundant over the southern (winter) pole, whereas the longer-lived CH 3 CN is more concentrated in the north. This abundance pattern is consistent with the combined effects of high-altitude photochemical production, poleward advection, and the subsequent reversal of Titan's atmospheric circulation system following the recent transition from northern to southern winter. We confirm that C 2 H 3 CN and C 2 H 5 CN are most abundant at altitudes above 200 km. Using a 300 km step model, the average abundance of C 2 H 3 CN is found to be 3.03 ± 0.29 ppb, with a C 2 H 5 CN/C 2 H 3 CN abundance ratio of 2.43 ± 0.26. Our HC 3 N and CH 3 CN spectra can be accurately modeled using abundance gradients above the tropopause, with fractional scale-heights of 2.05 ± 0.16 and 1.63 ± 0.02, respectively.