Background Accurate assessment of volume responsiveness in elderly patients is important as it may reduce the risk of post-operative complications and enhance surgical recovery. This study evaluated the utility of two Doppler ultrasound-derived parameters, the carotid corrected flow time (FTc) and respirophasic variation in carotid artery blood flow peak velocity (ΔVpeak), to predict volume responsiveness in elderly patients under general anaesthesia. Methods A total of 97 elderly patients undergoing elective abdominal surgery under general anaesthesia were enrolled in this prospective observational study. After entering the operating room, all patients underwent radial artery puncture connected with a LiDCO device to measure stroke volume variation (SVV), and fluid therapy was performed after anaesthesia induction. Patients were classified as responders if SVV ≥ 13% before fluid challenge and nonresponders if SVV < 13%. The FTc, ΔVpeak, SVV and haemodynamic data were measured by ultrasound at baseline (T0) and before (T1) and after (T2) fluid challenge. The correlations between the Doppler ultrasound-derived parameters and SVV were analysed, and the receiver operating characteristic (ROC) curves was computed to characterize both FTc and ΔVpeak as measures of volume responsiveness in elderly patients. Results Forty-one (42.3%) patients were fluid responders. Carotid FTc before fluid challenge was negatively correlated with SVV before fluid challenge (r = -0.77; P < 0.01), and ΔVpeak was positively correlated with SVV (r = 0.72; P < 0.01). FTc and ΔVpeak predicted SVV ≥ 13% after general anaesthesia in elderly patients, with areas under the receiver operating characteristic curves (AUROCs) of 0.811 [95% confidence interval (CI), 0.721–0.900; P < 0.001] and 0.781 (95% CI, 0.686–0.875; P < 0.001), respectively. The optimal cut-off values of FTc and ΔVpeak to predict SVV ≥ 13% were 340.74 ms (sensitivity of 76.8%; specificity of 80.5%) and 11.69% (sensitivity of 78.0%; specificity of 67.9%), respectively. Conclusions There was a good correlation between carotid artery ultrasound parameters and SVV. FTc predicted fluid responsiveness better than ΔVpeak in elderly patients during general anaesthesia. Further study is needed before these parameters can be recommended for clinical application. Trial registration www.chictr.org.cn(ChiCTR2000031193); registered 23 March 2020.

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Background: Remimazolam is a novel ultrashort-acting intravenous benzodiazepine sedative–hypnotic that significantly reduces the times to sedation onset and recovery. This trial was conducted to confirm the recovery time from anesthesia of remimazolam-flumazenil versus propofol in patients undergoing endotracheal surgery under rigid bronchoscopy. Methods: Patients undergoing endotracheal tumor resection or stent implantation were randomly allocated into a remimazolam group (Group R) or a propofol group (Group P). The primary outcome was the recovery time from general anesthesia. The secondary outcomes were the time to loss of consciousness (LoC), hemodynamic fluctuations, and adverse events. Results: A total of 34 patients were screened, and 30 patients were enrolled in the study. The recovery time was significantly shorter for Group R (140 ± 52 s) than for Group P (374 ± 195 s) (p < 0.001). The times to LoC were 76 ± 40 s in Group R and 75 ± 25 s in Group P and were not significantly different. There were also no significant differences in hemodynamic fluctuations or adverse events between the two groups. Conclusions: The recovery time from general anesthesia in rigid bronchoscopy patients was shorter using remimazolam-flumazenil than with propofol, with no dramatic hemodynamic fluctuations and adverse events or differences between the agents. Remimazolam-flumazenil allows for faster recovery from anesthesia than propofol.

Here in this paper, we report a room-temperature operating infrared photodetector based on the interband transition of an InAsSb/GaSb quantum well. The interband transition energy of 5-nm thick InAs 0.91 Sb 0.09 embedded in the GaSb barrier is calculated to be 0.53 eV (2.35 µm), which makes the absorption range of InAsSb cover an entire range from short-wavelength infrared to long-wavelength infrared spectrum. The fabricated photodetector exhibits a narrow response range from 2.0 µm to 2.3 µm with a peak around 2.1 µm at 300 K. The peak responsivity is 0.4 A/W under −500-mV applied bias voltage, corresponding to a peak quantum efficiency of 23.8% in the case without any anti-reflection coating. At 300 K, the photodetector exhibits a dark current density of 6.05×10 −3 A/cm 2 under −400-mV applied bias voltage and 3.25×10 −5 A/cm 2 under zero, separately. The peak detectivity is 6.91×10 10 cm•Hz 1/2 /W under zero bias voltage at 300 K.