[Determination of the block range of ultrasound-guided lumbar erector spinal plane and its application in lumbar spine surgery].

Objective: To determinate the block range of lumbar erector spinal plane (ESPB), and investigate the efficacy of ESPB in lumbar spine surgery. Methods: Forty patients who underwent posterior lumbar fusion in the Second Affiliated Hospital of Wenzhou Medical University from November 2019 to August 2020 were randomly divided into two groups (with n=20 in each group) using the random number table: the experimental group (group E) and control group (group C). All the patients received ultrasound-guided bilateral ESPB with 20 ml of 0.375% ropivacaine (group E) or equal volume of normal saline (group C) on each side before induction of general anesthesia. The range of weakened temperature sense in each patient was measured at 10 min, 20 min and 30 min after ESPB, respectively. Dosage of analgesic drug, visual analog scale (VAS), and incidence of adverse events were recorded and compared between the two groups. Results: In group E, the dermatomal distribution and area of weakened temperature sense at 10 min, 20 min, 30 min after ESPB were T9-S1 (222±16) cm2, T8-S2 (352±22) cm2, T8-S3 (481±24) cm2, respectively. The intraoperative dosage of remifentanil in group E was (0.76±0.02) mg, which was significantly lower than that of group C (0.97±0.06) mg (P<0.05). Oxycodone consumption in group E at 0-12 h and 12-24 h after surgery was (4.9±0.4) mg and (8.4±1.2) mg, respectively, which were lower than those in group C [(14.5±2.4) mg and (19.3±2.4) mg, respectively] (both P<0.05). The VAS during rest and movement within 24 h after operation in group E were significantly lower than those in group C (both P<0.05). The passive exercise in bed in group E started at (3.3±0.3) h postoperatively, which was earlier than that in group C (4.6±0.3) h (P<0.05). Conclusion: The blocking effects of T12-S1 segment after ultrasound-guided lumbar ESPB is definite, which can effectively decrease the amounts of analgesics during and after the lumbar fusion surgery, reduce postoperative rest and exercise VAS score, and contribute to a rapid recovery of the patients.

[Determination of major components in Psoralea corylifolia L. by using supercritical fluid extraction (SFE)].

A method based on SFE and CGC has been developed for qualitative and quantitative analysis of major components in Psoralea corylifolia L.. The orthogonal design method and the analysis of variance are used to optimize the five variables (temperature, pressure, volume of modifier, static extraction time and CO2 dynamic extracting volume) of SFE and the optimized conditions listed as follows: temperature 70 degrees C, pressure 38.5 MPa, static extraction 1 min, dynamic extraction 7 mL and 60 microL CHCl3 as modifier. The recoveries of psoralen and isopsoralen are 96.93% (RSD 1.87%) and 98.43% (RSD 2.06%) respectively. Being compared with conventional methods, the SFE as an alternative technique for sample preparation will be most useful in the quality control of Chinese traditional medicines.

[Single-pump on-line addition of modifier for supercritical fluid chromatography].

Modified CO2 as mobile phase is usually necessary for packed-column supercritical fluid chromatography. Single syringe pump was applied in this work to add modifier through a parallel connection device, which can maintain constant and stable volume fraction of modifier without any contamination of the pump. Viscosity of the modifiers (here are methanol and acetone) and the length of the CO2 pipe line/modifier pipe line can affect the volume fraction. Volume fractions of methanol and acetone were determined by gas chromatography and ultraviolet spectrometry respectively and their rules of variation were also examined. It shows that the volume fraction of methanol is lower than that of acetone under similar condition. With fixed modifierr line, the longer the CO2 line is, the higher the volume fraction will be. The new device can conveniently alter the nature and ratio of the modifier with quite stable volume fraction. The online addition device can tentatively replace the dual-pump system.

Determination of salicylic acid in plasma by gas chromatography using steam as carrier gas.

A gas chromatography method using steam as the carrier gas was established for the determination of salicylic acid in plasma. A 0.5 mL plasma sample was mixed with 0.5 mL of 6N HCl and then extracted with 2 mL of dichloromethane. The dichloromethane was evaporated to dryness and the residue was redissolved in 0.5 mL of water and then analysed by gas chromatography using steam as the carrying gas. The result was calculated by external standardization.