Browsing by Author "Yimam, Ali"

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    Assessment of dissatisfaction, refusal and associated factors after spinal anaesthesia for elective surgical procedures in public hospitals in Addis Ababa, Ethiopia, 2020/2021, A cross sectional study
    (Addis Abeba University, 2021-06) Yimam, Ali; Seifu, Ashenafi (BSc, MSc)
    Background: Spinal anaesthesia is the most common type of regional anaesthesia technique which helped for a wide range of surgical procedures. Patient satisfaction with anaesthesia care is important to monitor the quality of anaesthesia delivery system. It is important to identify the reasons and the risk factors for patients’ dissatisfaction and refusal after spinal anaesthesia for continuous improvement of quality of anaesthesia services. Objectives: The aim of this study was to assess the dissatisfaction, refusal and associated factors after spinal anaesthesia for elective surgical procedures in public hospitals in Addis Ababa, Ethiopia, 2020/2021. Methods: A multicentre cross-sectional study was conducted from December 30 to April 14, 2020/2021, in selected public hospitals in Addis Ababa, Ethiopia. A total of 227 patients older than 18 years old scheduled for elective surgery under spinal anaesthesia were incorporated in the study. A five point likert scale was used to assess patients preoperative, intraoperative, and postoperative satisfaction level of anaesthesia service. Both bivariate and multivariate logistic regressions were used to measure association of predictor and outcome variable at 95% CI using adjusted odds ratio. P value <0.05 was used to declare statistical significance. Results: A total of 227 patients included in this study and overall proportion of patients who were satisfied with spinal anaesthesia was 150 (66.1%). Risk factors of dissatisfaction were backache (AOR=4.73, 95%CI=1.97, 11.36), headache (AOR=3.68, 95%CI=1.54, 8.80), and intraoperative nausea &vomiting (AOR=3.33(1.43, 7.73). 188(83%) of patients would choose spinal anaesthesia again whereas 39(17%) would refuse to undergo spinal anaesthesia in the future and its risk factors were intraoperative pain, fear of awareness and backache. Conclusion and recommendation: Patients satisfaction towards spinal anaesthesia was very low in our setup compared to many other previous studies. Backache, headache and intraoperative nausea and vomiting were risk factors which results patients dissatisfaction. Explaining the benefits and risks of anaesthesia, and understanding the patient’s opinion is essential to increase satisfaction with anaesthesia service.
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    Disign and Implementation of Solar wind Hybrid Engener System for maximizing lifspon of field Deployed wirless sensor Network (WSN)
    (Addis Ababa University, 2017-02) Yimam, Ali; Negash, Yalemzewd(PhD)
    A Wireless Sensor Network (WSN) is composed of a large number of sensor nodes that are densely deployed either inside a phenomenon or very close to it. The main challenge for the researchers in the field of WSNs is maintaining network lifespan until the mission of the network is completed. This challenge is coming from the nodes limited energy source of fixed amount capable primary battery which has no option to maintain its energy by recharging. And also changing it with another battery is impossible if the field that the network located is inaccessible. This thesis addresses this challenge with the design and implementation of harvested energy source for the sensor node’s rechargeable battery from the hybrid power sources of solar irradiance and wind speed. In addition, energy management system is designed for managing the on/off states of sensor nodes due to uncontrollable property of the power source used here. And also, energy efficient LEACH algorithm is incorporated for assisting the sensor nodes to use the charged energy efficiently. Besides this, simulation experiment is done to show what can be the behavior of remaining energy in case of supplying sensor nodes from fixed amount capable primary battery and from the harvested energy stored in rechargeable battery and supper capacitor. This experiment is made on three IDEs known as Omnet++, Castalia and greenCastalia by integrating them together. At the end quantitative and qualitative analysis of obtained results is done. From the result analysis one can observe the network lifespan is prolonged when harvested energy is used together with the management system for uncontrolled behavior of the sources (solar and wind) rather than fixed capable battery. Hence, for field deployed WSNs, utilizing naturally existed abundant energy sources like solar and wind have promising solutions for the challenged network lifespan without exerting any negative impact for the environment at which they are deployed. The simulation result also confirms this by generating 98 and 96% residual energy for rechargeable battery and supper capacitor respectively over that of 86% for fixed capable battery after 5000seconds of operation time completed. Keywords: Energy Harvesting, Wireless Sensor Network, Lifespan, Remaining Energy, Solar-Wind Hybrid Power Source, Rechargeable Battery, Power Efficient Routing Algorithm.