Cognitive Dysfunction After Cataract Surgery
Condition: POCD - Postoperative Cognitive Dysfunction
MeSH terms: Cataract; Capsule Opacification; Postoperative Cognitive Complications; Cognitive Dysfunction
Study type: Interventional

Summary: 
      -  Cataract surgery is commonly performed in elderly patients who are at high risk for
           developing postoperative cognitive dysfunction. Most cataract surgeries are performed
           under peribulbar or retrobulbar anesthesia, however, most of the patients require
           sedation to relieve the perioperative anxiety and induce amnesia. So, many sedative
           agents can be used especially benzodiazepines which may increase the risk of developing
           postoperative cognitive dysfunction.

        -  Ketamine can be used as a sedative and analgesic agent in a dose of 0.25 -0.5 mg/kg with
           certain studies suggesting that it may decrease the risk of postoperative cognitive
           dysfunction. Similarly, dexmedetomidine can be used as a sedative and analgesic agent
           with the possibility of decreasing the incidence of postoperative cognitive dysfunction.

        -  this controlled study will compare the effect of ketamine or dexmedetomidine on the POCD
           of patients undergoing cataract surgery.
    

Detailed description: 
      -  Postoperative cognitive dysfunction is a common postoperative complication in elderly
           patients. Despite the role of the risk of anesthesia and/or surgery in developing
           postoperative cognitive dysfunction, it can be developed even with surgeries performed
           under local or regional anesthesia.

        -  Ageing is the most common risk factor for developing postoperative cognitive dysfunction
           that can affect memory and speech. Also, impaired vision may be another important risk
           factor.

        -  Cataract surgeries can be considered the most common surgery performed in elderly
           patients. It is usually performed under local anesthesia (peribulbar, retrobulbar, or
           sub-tenon blocks), however, sedation is usually required to relieve the anxiety of the
           patients and induce amnesia.

        -  there are many sedative agents that can be used with such patients, the most commonly
           used are benzodiazepines. However, benzodiazepines use may increase the incidence of
           postoperative cognitive dysfunction.

        -  Ketamine, the dissociative anesthetic, acts mainly through inhibition of NMDA receptors
           that reduce the neuronal loss of the cortex. it may attenuate the postoperative
           cognitive dysfunction and induce neuroprotective effect through suppressing the
           inflammatory response and minimizing cerebral ischemia.

        -  dexmedetomidine is a sedative and analgesic agent that have the advantage of minimal
           respiratory depression and can be used as a sedative agent in cataract surgery. Studied
           revealed that its sedative analgesic effect is not associated with changes in memory.

        -  This randomized controlled double-blinded study will be carried upon 90 elderly patients
           undergoing cataract surgery under peribulbar anesthesia where they will be classified
           into 3 groups: - Group I (Placebo Group). Where the patients will receive normal saline
           as a placebo.

      Group II (Ketamine group). Where patients will receive ketamine in a dose of 0.3 mg/kg in
      physiological solution.

      Group III (Dexmedetomidine group). where patients will receive dexmedetomidine in a dose of
      0.5 ug/kg in a physiological solution.

      -Primary outcome will be the incidence of POCD, the secondary outcomes will be the
      hemodynamic changes and the changes in the intraocular pressure.
    

Intervention name(s): Ketamine; Dexmedetomidine; Normal saline
Intervention type(s): Drug; Drug; Drug
Intervention description(s): Ketamine at a dose of 0.3 mg/kg dissolved in normal saline.; Dexmedetomidine at a dose of 0.5 ug/kg dissolved in normal saline.; Normal saline in a labeled syringe
Intervention MeSH terms: Dexmedetomidine; Ketamine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Supportive Care
Keywords: Ketamine; Dexmedetomidine; cataract; Cognitive dysfunction