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.
Publisher
University of Nairobi
Rights
Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
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