Comparative Study between the Effects of Intravenous or Intrathecal Dexmedetomidine on Characteristics of Bupivacaine Spinal Block in Lower Limb Orthopedic Surgeries

Abstract

Lower limb orthopedic surgeries performed under spinal anesthesia has the advantage of having rapid onset, maintaining spontaneous breathing, relaxing the necessary muscles for surgery, and cost effectiveness. It also has the advantage of being free from the risks of intubation and pulmonary aspiration. Prolonging the duration of spinal anesthesia would allow longer surgical interventions. Various additives have been used in order to prolong the duration of spinal anesthesia e.g ketamine, magnesium and clonidine. Agents such as opioids and neostigmine have also been used. Dexmedetomidine is a centrally acting α2 receptor agonist that can be titrated to the desired level of sedation without significant respiratory depression. It has an analgesic-sparing effect, significantly reducing Opioid requirements both during and after surgery. Dexmedetomidine also has a sympatholytic effect that can attenuate the stress response to surgery mitigating tachycardia and hypertension. Because of its analgesic properties, "cooperative sedation" and lack of respiratory depression, Dexmedetomidine is increasingly being used as a sedative and adjuvant in anesthesia. Dexmedetomidine has been used safely in patients undergoing surgical procedures under regional anesthesia. Intravenous and intrathecal dexmedetomidine showed to