[Comparing the effect of pethedine, dexamethasone and placebo on preventing post-operation shivering]

Post-operation shivering is very common and followed by many problems such as increased oxygen consumption, blood pressure, intracranial and intraocular pressure, and post-operation pain. Therefore, prevention of shivering is important especially in elderly and ischemic heart disease patients. The goal of this study was comparing the effect of Pethedine [Meperidin], Dexanethasione and Placebo on prevention of shivering. This double blind clinical trial study was carried out on 114 patients of ASA class I and II who were candidates for elective abdominal surgery under general anesthesia. The patients were randomly divided into three groups including those who received Pethedine [P], Dexamethasone [D] and Placebo [N]. Induction and maintenance of anesthesia for all patients were similar. Temperature of patients was measured in 4 steps: before induction, before extubation, in the beginning of recovery and the end of recovery. Five minutes before the ending of the surgery 0.3mg/kg of Pethedine, 0.1mg/kg of Dexamethasone and 3ml of saline 0.9% were injected to groups P, D and N respectively. N recovery all patients were controlled for visible shivering. 25 mg of Pethedine was injected intravenously while shivering. All data were statistically analyzed by SPSS software and ANOVA and chi square tests. There were no significant differences among three mentioned groups regarding of gender, age and duration of surgery. 18 cases [47.4%] in group N had post-op shivering. Whereas, in group D only 7 cases [18.4%] had shivering and the difference was significant [P value=0.0001]. Also in group P just 3 cases [7.9%] had shivering that the difference from Placebo group was significant [P value=0.0001]. But the difference between group P and D was not significant too [P value= 0.155]. The present study showed that Pethedine and Dexamethasone are effective drugs for preventing the post-op shivering in elective abdominal surgery

Determination of the ultrasonic effectiveness in advanced wastewater treatment

Ultrasonic technology may be used for water and wastewater treatment as an advanced oxidation process. Application of this technology, leads to the decomposition of many organic compounds during cavitation process. In this study, the efficiency of ultrasonic in advanced treatment of municipal wastewater has been investigated by use of an ultrasonic bath. COD and BOD[5] tests were used as the indicators of organic matter concentrations and three detention times for treatment were appointed at 10, 30 and 60 minutes. Two frequencies of 35 and 130 kHz for sonication were used. Results indicated that sonication can reduce 25% to 30% of COD in less than 60 minutes. Also, it was indicated that suspended COD was mainly converted to soluble COD during sonication. The rate of hydrogen peroxide production and thus the efficiency of treatment were higher at 130 kHz, but this efficiency was not much increased by prolonging sonication time. In other words, maximum efficiency was achieved at the initial time of sonication. Furthermore, no considerable change in nutrients concentration was detected and pH variations of samples were negligible [<0.3]. In contrast, significant temperature change occured which was about [18-20] degree C increase in 60 minutes. However, this temperature change had no considerable effect on treatment efficiency