[Preliminary application value of ultrasound contrast agent with enteral nutritional suspension as mixed medium in locating indwelling nasointestinal tube in critically ill patients].

Objective: To evaluate the value of ultrasound contrast agent with enteral nutrition suspension as mixed medium in locating indwelling nasointestinal tube in critically ill patients. Methods: Total of 45 critically ill patients had nasointestinal tube indwelled were collected from June 1,2018 to April 1,2019 in the Intensive Care Unit of Zhejiang Provincial People's Hospital, including 30 males and 15 females, with an average age of (63±17) years.Enteral nutritional suspension Peptisorb Liquid was used as research medium,with the ultrasonic imaging performance of it confirmed by in vitro and in vivo experiments.The optimal mixing ratio of microbubble ultrasound contrast agent and Peptisorb Liquid was confirmed by in vitro experiment, then the mixture was quietly placed and its stability was dynamically observed. The nasointestinal tube was confirmed in the digestive tract by conventional ultrasound and then the ultrasound contrast mode turned on. Ultrasound contrast agent with Peptisorb Liquid as mixed medium was injected into the nasointestinal tube and the tube direction and end position were observed and recorded in real time. Abdominal X-ray examination or CT was used as the gold standard for verifying the location of the nasointestinal tube and the same result represented successful positioning. Results: The in vitro and in vivo experiments showed that Peptisorb Liquid had good ultrasound imaging uniformity and penetrating power, which could clearly show the range and boundary of the filling intestine cavity; the in vitro experiment showed that the ultrasound contrast agent prepared with the microbubble ultrasound contrast agent and Peptisorb Liquid by the ratio of 1∶1 000 and 1∶500 which had the best imaging effect and the best distribution uniformity, with the best stability within 10 minutes after quietly placed. Nasointestinal tubes were successfully located by using ultrasound contrast agent with enteral nutritional suspension as mixed medium in 95.6%(43/45) of the patients collected in this study,including success at one attempt in 39 cases, the operating time was (1.6±0.5) minutes and 4 cases were successfully located after multiple operations with (5.1±0.5) minutes, the tube bent in the stomach in one case and flexed back into the stomach from the descending duodenum in another. The operation failed in 2 cases (4.4%). No significant complications occurred during the examination. Conclusion: The ultrasound contrast agent with enteral nutritional suspension as mixed medium has the advantages of both, which can conveniently, safely and effectively locate the direction and end position of nasointestinal tube in critically ill patients.

[Quick confirmation of nasointestinal tube placed below pylorus in critically ill patients by duodenal bulb ultrasonic anatomy locating method].

Objective: To investigate the value of duodenal bulb ultrasonic anatomy locating method quickly confirm nasointestinal tube placed below pylorus in critically ill patients. Methods: A total of 56 critically ill patients with nasointestinal tube posting surgery by blindly inserting method were collected from March 1 st, 2016 to August 1 st, 2016 in the Department of Critical Care Medicine of Zhejiang Provincial People's Hospital.In these patients, the duodenal bulbs were rapidly detected and located by ultrasonic anatomy locating method and at the same time observed whether nasointestinal tube echogram were in them or not. If nasointestinal tube echogram was observed in duodenal bulbs that meant nasointestinal tube placed below pylorus successfully. If disturbed by ultrasound artifacts or other reasons, injected gas into the nasointestinal tube could help to confirm when hyperechoic strip emerged. Gastrointestinal decompression or gastrointestinal motion promoting drug could help to reduce the interference of abdominal cavity or bowel gas if necessary. The results were compared with the abdominal X examination to vertify the accuracy of this method, and at the same time recorded its total time-consuming and its related complications. Results: The duodenal bulbs were rapidly located by ultrasonic anatomy locating method in 53 cases(94.6%) time-consuming(42±23)s. Nasointestinal tubes observed in duodenal bulb were confirmed to be placed below pylorus successfully in 52 cases(92.9%)time-consuming(140±94)s.There were no obvious complications in all patients. Conclusion: Duodenal bulb ultrasonic anatomy locating method is a safe, simple and convenient method with high accuracy that can quickly confirm whether nasointestinal tube placed below pylorus in critically ill patients or not.

Role of 5G-powered remote robotic ultrasound during the COVID-19 outbreak: insights from two cases.

The 2019 Novel Coronavirus disease (COVID-19) broke out in Wuhan, China in December 2019 and spread throughout the world. Early screening and early diagnosis play key roles in prevention and management of the epidemic. Attention should also be paid to the infection of health workers and shortage of medical resources in high-risk areas. Here, we report two cases of patients diagnosed with COVID-19 and evaluated by robotic ultrasound based on 5G-powered technology 700 km east of Wuhan. We here show the advantages of this kind of remote ultrasound scan, which could become a method for the diagnosis and assessment of COVID-19.

Noniterative calculation of complex propagation constants in planar waveguides.

We adapt an efficient finite-difference procedure for determining complex propagation constants to the analysis of modes in planar waveguides. The method requires solving a single rather than multiple eigenvalue equations and does not require prior knowledge of either the nature of the solutions or the position of the modal eigenvalues in the complex plane.