Assessment of the 50 % and 95 % effective paratracheal forces for occluding the esophagus in anesthetized patients.

This study aimed to evaluate the 50% and 95% effective paratracheal forces for occluding the esophagus in anesthetized patients. In 46 anesthetized patients, the upper esophagus was examined using ultrasonography, and the lower paratracheal area over the esophagus just above the clavicle was marked. Manual paratracheal force was applied over that area using a novel pressure sensing device set-up. In the first patient, a 20 N paratracheal force was applied, and the patency of the esophagus was assessed by advancing the esophageal stethoscope. Unsuccessful advancement of the esophageal stethoscope was considered an effective paratracheal force. If advancement of the esophageal stethoscope was successful, the paratracheal force was increased by 2 N for the next patient, and if it was unsuccessful, the force was decreased by 2 N for the next patient. These sequential tests were performed using 12- and 18-Fr esophageal stethoscopes, respectively. According to Dixon and Mood method, the 50% effective paratracheal force (confidence interval) was 18.4 (17.5‒19.3) N with the use of a 12-Fr esophageal stethoscope and 12.8 (11.0‒14.6) N with the use of an 18-Fr esophageal stethoscope. Using probit regression analysis, the 50% and 95% effective paratracheal forces were 18.4 (16.8‒19.6) N and 20.6 (19.4‒27.9) N, respectively, with the use of a 12-Fr esophageal stethoscope, and 12.4 (8.3‒14.4) N and 16.9 (14.7‒37.3) N, respectively, with the use of an 18-Fr esophageal stethoscope. Our findings suggest a guide for applying paratracheal force during rapid sequence induction and tracheal intubation.

Honeycomb-like MoS2 Nanotube Array-Based Wearable Sensors for Noninvasive Detection of Human Skin Moisture.

Technological advances in wearable electronics have driven the necessity of a highly sensitive humidity sensor that can precisely detect physiological signals from the human body in real time. Herein, we introduce the anodic aluminum oxide (AAO)-assisted MoS2 honeycomb structure as a resistive humidity sensor with superior sensing performance. The unique honeycomb-like structure consists of MoS2 nanotubes, which can amplify the sensing performance because of their open pores and wider surface absorption sites. The formation of uniform MoS2 nanotubes inside the AAO membrane was manipulated by the number of vacuum filtration cycles of the (NH4)2MoS4 solution. The proposed humidity sensor exhibits an elevated sensitivity that is 2 orders of magnitudes higher than the MoS2 film-based humidity sensor at the relative humidity range of 20-85%. Moreover, the sensor showed significantly faster response and recovery times of 0.47 and 0.81 s. In addition, we demonstrate the multifunctional applications such as noncontact sensation of human fingertips, human breath, speech recognition, and regional sweat rate, which show its promising potential for the next-generation wearable sensors.

Highly Sensitive and Flexible Strain-Pressure Sensors with Cracked Paddy-Shaped MoS2/Graphene Foam/Ecoflex Hybrid Nanostructures.

Three-dimensional graphene porous networks (GPNs) have received considerable attention as a nanomaterial for wearable touch sensor applications because of their outstanding electrical conductivity and mechanical stability. Herein, we demonstrate a strain-pressure sensor with high sensitivity and durability by combining molybdenum disulfide (MoS2) and Ecoflex with a GPN. The planar sheets of MoS2 bonded to the GPN were conformally arranged with a cracked paddy shape, and the MoS2 nanoflakes were formed on the planar sheet. The size and density of the MoS2 nanoflakes were gradually increased by raising the concentration of (NH4)2MoS4. We found that this conformal nanostructure of MoS2 on the GPN surface can produce improved resistance variation against external strain and pressure. Consequently, our MoS2/GPN/Ecoflex sensors exhibited noticeably improved sensitivity compared to previously reported GPN/polydimethylsiloxane sensors in a pressure test because of the existence of the conformal planar sheet of MoS2. In particular, the MoS2/GPN/Ecoflex sensor showed a high sensitivity of 6.06 kPa-1 at a (NH4)2MoS4 content of 1.25 wt %. At the same time, it displayed excellent durability even under repeated loading-unloading pressure and bending over 4000 cycles. When the sensor was attached on a human temple and neck, it worked correctly as a drowsiness detector in response to motion signals such as neck bending and eye blinking. Finally, a 3 × 3 tactile sensor array showed precise touch sensing capability with complete isolation of electrodes from each other for application to touch electronic applications.

High Durability and Waterproofing rGO/SWCNT-Fabric-Based Multifunctional Sensors for Human-Motion Detection.

Wearable strain-pressure sensors for detecting electrical signals generated by human activities are being widely investigated because of their diverse potential applications, from observing human motion to health monitoring. In this study, we fabricated reduced graphene oxide (rGO)/single-wall carbon nanotube (SWCNT) hybrid fabric-based strain-pressure sensors using a simple solution process. The structural and chemical properties of the rGO/SWCNT fabrics were characterized using scanning electron microscopy (SEM), Raman, and X-ray photoelectron spectroscopy (XPS). Complex networks containing rGO and SWCNTs were homogeneously formed on the cotton fabric. The sensing performance of the devices was evaluated by measuring the effects of bending strain and pressure. When the CNT content was increased, the change in relative resistance decreased, while durability was significantly improved. The rGO/SWCNT (0.04 wt %) fabric sensor showed particularly high mechanical stability and flexibility during 100 000 bending tests at the extremely small bending radius of 3.5 mm (11.6% bending strain). Moreover, the rGO/SWCNT fabric device exhibited excellent water resistant properties after 10 washing tests due to its hydrophobic nature. Finally, we demonstrated a fabric-sensor-based motion glove and confirmed its practical applicability.