[Effective dose and adverse reactions analysis of Remimazolam for sedation in elderly patients undergoing gastroscopy].

Objective: To explore the 50% effective dose (ED50) and 95% effective dose (ED95) of Remimazolam during gastroscopic sedation in elderly patients, and to observe the adverse reactions during anesthesia. Methods: From July to November 2020, 39 elderly patients, of which there were 18 males and 21 females, aged from 65 to 82 (72±5) years, were examined by gastroscopy in the Second Affiliated Hospital of Hainan Medical University, who American Society of Anesthesiologists (ASA) was grade Ⅰ or Ⅱ. Sufentanil 0.1 µg/kg and test dose Remimazolam were injected intravenously, and the initial dose of Remimazolam was 0.17 mg/kg. The dose of the next patient was determined according to the modified Dixon sequential method. If the former patient had a positive reaction during gastroscopy, such as cough, nausea, vomiting and/or body movement reaction occurred when the gastroscope was placed into the pharynx or in the 2 min, the next patient would increase the dose, otherwise, the dose would be reduced. The dose increase and decrease gradient of Remimazolam was 0.01 mg/kg, and the test was stopped after 12 times of return. At the same time, the occurrence of adverse reactions during anesthesia was observed. Results: A total of 39 elderly patients completed the trial, of which 21 were effective and 18 were ineffective. When the elderly patients were sedated by gastroscopy, the ED50 of single intravenous injection of Remimazolam was 0.153 mg/kg (95%CI:0.151-0.154 mg/kg) and the ED95 was 0.164 mg/kg (95%CI:0.160-0.166 mg/kg). The total dose of Remimazolam was (10.6±2.8) mg, the recovery time was (10.0±3.4) min, and the stay time in resuscitation room was (8.2±2.6) min. During anesthesia, nausea and vomiting occurred in 1 case, transient hypotension in 4 cases, and no other adverse reactions were found. Conclusion: The ED50 of Remimazolam during gastroscopic sedation in elderly patients is 0.153 mg/kg, ED95 is 0.162 mg/kg, and the incidence of adverse reactions is low.

Recovery of gastrointestinal function with thoracic epidural vs. systemic analgesia following gastrointestinal surgery.

The objective of this review was to systematically assess the effect of thoracic epidural analgesia (TEA) vs. systemic analgesia (SA) on the recovery of gastrointestinal (GI) function in patients following GI surgery. We performed a comprehensive literature search to identify randomized controlled trials of adult patients undergoing GI surgery, comparing the effect of two postoperative analgesia regimens. Patients postoperatively receiving local anesthesia-based TEA with or without opioids were compared to patients receiving opioid-based SA. The outcomes considered were times to GI function recovery, GI complications, and specific side effects. Twelve studies with 331 patients in the TEA group and 319 in the SA group were included. Compared to SA, TEA improved the GI recovery after GI procedures by shortening the time to first passage of flatus by 31.3 h, 95% confidence intervals (CIs): -33.2 to -29.4, P < 0.01; and shortening the time to first passage of stool by 24.1 h, 95% CIs: -27.2 to -20.9, P < 0.001. There was no difference between the groups in the incidence of anastomotic leakage and ileus. The occurrence of postoperative hypotension was relatively higher in the TEA group, risk ratio: 7.9, 95% CIs: 2.4 to 26.5, P = 0.001; other side effects (such as pruritus and vomiting) were similar in the two groups. There is evidence that TEA (compared to SA) improves the recovery of GI function after GI procedures without any increased risk of GI complications. To further confirm these effects, larger, better quality randomized controlled trials with standard outcome measurements are needed.

Entropy generation across Earth's collisionless bow shock.

Earth's bow shock is a collisionless shock wave but entropy has never been directly measured across it. The plasma experiments on Cluster and Double Star measure 3D plasma distributions upstream and downstream of the bow shock allowing calculation of Boltzmann's entropy function H and his famous H theorem, dH/dt≤0. The collisionless Boltzmann (Vlasov) equation predicts that the total entropy does not change if the distribution function across the shock becomes nonthermal, but it allows changes in the entropy density. Here, we present the first direct measurements of entropy density changes across Earth's bow shock and show that the results generally support the model of the Vlasov analysis. These observations are a starting point for a more sophisticated analysis that includes 3D computer modeling of collisionless shocks with input from observed particles, waves, and turbulences.

Experimental observations and density functional simulations on the structural transition behavior of a two-dimensional transition-metal dichalcogenide.

In this work, we show an obvious evidence of nondestructive Raman spectra for the structural transition, i.e., the existence of a charge density wave (CDW) in monolayer 2H-TaS2, which can exhibit a much higher transition temperature than bulk and results in additional vibrational modes, indicating strong interactions with light. Furthermore, we reveal that the degenerate breath and wiggle modes of 2H-TaS2 originated from the periodic lattice distortion can be probed using the optical methods. Since recently several light-tunable devices have been proposed based on the CDW phase transition of 1 T-TaS2, our study and in particular, the theoretical results will be very helpful for understanding and designing electronic devices based on the CDW of 2H-TaS2.

Magnetic reconnection in the near Venusian magnetotail.

Observations with the Venus Express magnetometer and low-energy particle detector revealed magnetic field and plasma behavior in the near-Venus wake that is symptomatic of magnetic reconnection, a process that occurs in Earth's magnetotail but is not expected in the magnetotail of a nonmagnetized planet such as Venus. On 15 May 2006, the plasma flow in this region was toward the planet, and the magnetic field component transverse to the flow was reversed. Magnetic reconnection is a plasma process that changes the topology of the magnetic field and results in energy exchange between the magnetic field and the plasma. Thus, the energetics of the Venus magnetotail resembles that of the terrestrial tail, where energy is stored and later released from the magnetic field to the plasma.