RESUMO
The study is dedicated to the consideration of lower alkyl ethers of glycerol as potential components of low-melting technical fluids (e.g., heat transfer fluids, hydraulic fluids, aircraft de-icing fluids, etc.). Four isomeric mixtures of glycerol ethers (GMME-monomethyl; GDME-dimethyl; GMEE-monoethyl; GDEE-diethyl) were synthesized from epichlorohydrin and methanol/ethanol in the presence of sodium and subjected to detailed characterization as pure compounds and as aqueous solutions (30-90 vol%). The temperature and concentration dependencies of density, viscosity, cloud point, boiling range, specific heat capacity, thermal conductivity, and rubber swelling were obtained. On the basis of the data obtained, a comparison was made between the aqueous solutions of glycerol ethers and of other common bases for low-melting liquids (glycerol, ethylene glycol, and propylene glycol). Pure glycerol ethers could potentially be used as technical fluids in a very wide temperature range-from -114 to 150 °C. It was further demonstrated that in low temperature applications (e.g., in low-temperature chiller systems) the glycerol-ether-based aqueous heat transfer fluids could provide enhanced efficiency when compared to the glycerol- or propylene-glycol-based ones due to their lower viscosities and favorable environmental properties.
RESUMO
OBJECTIVE: As the thoracolumbar interfascial plane (TLIP) block may be a promising alternative in spinal surgery, there is a need for timely meta-analysis of this method's effectiveness in different medical outcomes. METHODS: The meta-analysis of 6 randomized controlled studies on the application of TLIP block in spinal surgery was performed under the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. The primary outcome used for comparison was the mean difference (MD) of pain intensity scores at rest/in motion between patients receiving TLIP block and those receiving no block care. RESULTS: Our analysis favors TLIP block over no block (control group) for pain intensity at rest (MD with 95% confidence interval [CI] is -1.14 [-1.29, -0.99], P value <0.00001, I2 = 99%) and pain intensity in motion (MD with 95% CI is -1.49 [-1.73, -1.24], P value <0.00001, I2 = 99%) on postoperative day 1. Analysis also favors TLIP block in terms of cumulative fentanyl consumption on postoperative day 1 (MD is -166.64 mcg with 95% CI [-204.48, -128.80], P value <0.00001, I2 = 89%), postoperative side effects (risk ratio with 95% CI is 0.63 [0.44, 0.91], P value = 0.01, I2 = 0%), requests for supplementary/rescue analgesia (risk ratio with 95% CI is 0.36 [0.23, 0.49], P value <0.00001, I2 = 0%). The results are statistically significant. CONCLUSIONS: The TLIP block reduces postoperative pain intensity, opioid consumption, side effects, and requests for rescue analgesia after spinal surgery more than the no-block alternative.
