Extraction and Evaluation of the Fuel Properties of Tyre Pyrolysis Oil

Abstract

Background: Shivering is a repetitive and involuntary skeletal muscle activity that is caused by a fall in core temperature. The aim of shivering is to increase metabolic heat production to counter the fall in core body temperature. Shivering may occur during spinal anaesthesia. It causes undesirable events in patients. The magnitude of this problem varies widely in the literature. Broad Objectives: To establish the incidence of shivering and risk factors associated with shivering intraoperatively during lower limb orthopedic surgeries under spinal anaesthesia at Kenyatta National Hospital, Kenya. Study design and Sites: This was a prospective cohort study that was carried out in Kenyatta National Hospital’s main theatre. Participants and Methods: Study participants were adult patients undergoing elective lower limb orthopedic surgeries under spinal anesthesia. Linear systemic sampling was used to select 113 eligible study participants from elective orthopedic theatre lists. After administration of a standard spinal anaesthesia dose (3 ml of bupivacaine 0.5% and fentanyl 25 mcg), patients were observed and those that developed shivering were recorded and the grade noted. Factors that were likely to be associated with shivering were also observed and recorded. Data analysis: The data were analyzed using Statistical Package for the Social Sciences (SPSS) version 23. Categorical data were summarized and presented using frequencies and proportions. Mean and standard deviation was used to summarize parametric numerical data. Median and interquartile ranges were used to summarize nonparametric numerical data. Logistic regression (bivariate and multivariate) was used to identify predictors of shivering. The level of association between shivering and its risk factors were identified by the relative risk at a confidence interval of 95%. Variables with a p value of less than 0.05 were considered as statistically significant. 12 | P a g e Results: There were more male than female participants 96(85%) vs 17 (15%). The incidence of shivering among patients undergoing lower limb orthopedic surgery under spinal anaesthesia at KNH was 31% with a mean time to onset of shivering of 27.2 ±23.8 minutes. The patient factor associated with shivering was the development of hypothermia with a relative risk of 2.6(CI 1.1- 6.1, p=0.023) when compared to normothermic individuals. The environmental factor associated with shivering was the use of cold intravenous fluids at a relative risk of 0.2 (CI 0.04-0.9, p=0.025) when comparing warm and cold intravenous fluids. Conclusions: The risk factors for shivering were the development of hypothermia and use of cold intravenous fluids during spinal anaesthesia for lower limb elective orthopedic procedures. Age, sex, spinal block height, BMI and ambient operating room temperature were not associated with the development of shivering in this study. Intrathecal fentanyl for spinal anaesthesia alongside bupivacaine may have lowered the incidence of shivering.