Dexmedetomidine for prevention of propofol injection pain upon induction of anesthesia: a meta-analysis.

PURPOSE: Propofol injection pain is a very common problem during the induction of general anesthesia. The purpose of this review is to evaluate the effectiveness of dexmedetomidine for the prevention of propofol injection pain so as to provide evidence for future clinical applications. METHODS: PubMed, Embase, Cochrane library, and Google Scholar databases were searched for relevant randomized controlled trials examining the use of dexmedetomidine for the prevention of propofol injection pain. The pooled risk ratio (RR) with corresponding 95% confidence intervals (CI) was calculated employing fixed-effects or random-effects models, depending upon the heterogeneity of the included trials. Because of the wide variety of interventions investigated, three comparisons of studies were established, dexmedetomidine compared with saline, lidocaine, and ketamine. RESULTS: Compared with saline, dexmedetomidine allowed more patients to experience no pain upon propofol injection (RR = 0.26, 95% CI (0.18, 0.38), P < 0.00001). Dexmedetomidine at doses of < 1 µg/kg did not show superiority in relieving propofol injecting pain compared with lidocaine (RR = 1.28, 95% CI (0.82, 2.00), P = 0.04). Dexmedetomidine is less effective than ketamine in reducing pain on propofol injection with a statistically significant P value of < 0.000010 (RR = 1.93, 95% CI (1.51, 2.47)). The report of adverse effects is rare, dexmedetomidine is a safe method to reduce propofol injection pain. CONCLUSION: Pretreatment with dexmedetomidine may be a useful alternative for reducing pain on propofol injection, even though dexmedetomidine is less effective than lidocaine and ketamine.

Affinity regulation of the NH3 + H2O system by ionic liquids with molecular interaction analysis.

This work proposed using an adequate ionic liquid (IL) to weaken the affinity between NH3 and H2O as a potential solution to the issue of high-energy consumption involved in separating NH3 gas from liquid H2O. Two quaternary phosphonium-based ILs were selected according to an optimized regulation strategy. The regulation effects of the ILs were evaluated by the vapor-liquid equilibrium property of the NH3 + H2O + IL systems, and were compared with the regulation effects of traditional additives. The results showed that the expected effects were achieved by adding ILs. The regulation mechanisms of different strategies were discussed with respect to the molecular structure and chemical equilibrium for the first time limited to the authors' latest literature review. Finally, the IR spectra of the NH3 + H2O + IL systems were acquired and analyzed to verify the interactions of the ILs with NH3 and H2O.