Intraoperative Ketamine Versus Lidocaine Infusion on Postoperative Cognitive Dysfunction in Patients Undergoing Hip Surgery

Hip arthroplasty remains one of the most commonly used and successful contemporary surgical interventions performed in older adults. Hip fractures in the elderly have emerged as a serious injury that incurs high medical costs and public resources due to long-term bed rest, limitations of independent daily living, or death, more than 28,000 hip fractures occur annually; this number is rapidly rising with the aging population) .

Despite successful surgery, patients still may suffer short- or long-term postoperative cognitive dysfunction , due to long operative times, extensive trauma, and the possibility of fat emboli .

POCD, which reflects a negative change in an individual's cognitive trajectory, has increasingly been recognized as a complication in elderly patients. It is characterized by disturbances in consciousness, orientation, thinking, memory, and executive function after surgical anesthesia .

The potential pathogenesis of postoperative cognitive dysfunction involves neuroinflammation and oxidative stress secondary to anesthesia and surgery. Post-surgery inflammation is characterized by increased levels of inflammatory cytokines and mediators and vascular permeability. Excessive inflammation can disrupt the body's immune system, potentially leading to certain inflammation-related conditions .

postoperative cognitive dysfunction is a neurological dysfunction which may last for weeks, months or years and can delay recovery, extend hospital stays, and even increase patient mortality. The incidence of postoperative cognitive dysfunction varies between 20 and 40% in patients over 60 years old. Therefore, it is important to develop new strategies to prevent postoperative cognitive dysfunction , especially in elderly patients . However, there is still unclear. on the methods and treatments used to prevent and treat postoperative cognitive dysfunction , including dexmedetomidine, ketamine, ulinastatin, parecoxib, midazolam, lidocaine, and dexamethasone.

Systemic lidocaine possesses analgesic, antihyperalgesic, prokinetic, and anti-inflammatory properties. It inhibits the release of proinflammatory cytokines and superoxide anions from activated neutrophils and blocks their accumulation at the injury site. The use of intravenous lidocaine infusions is associated with better pain relief, decreased risk of postoperative ileus, and improved enhanced recovery after surgery outcomes .

Ketamine, a non-competitive antagonist of N-methyl-d-aspartate receptors, exerts its primary mechanism of action by blocking N-methyl-d-aspartate receptors on gamma-aminobutyric acid interneurons and activating alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. Ketamine possesses anti-inflammatory properties, including the reduction of microglia activation as well as downregulation of pro-inflammatory cytokines . Hence, this study aims to compare effects of ketamine and lidocaine on postoperative cognitive dysfunction in geriatric hip surgery patients.

This study aims to compare effects of ketamine versus lidocaine on postoperative cognitive dysfunction in geriatric patient undergoing hip surgery.

Inclusion criteria

• Both sexes of Elderly patient Aged >65 years.
• American Society of Anesthesiologists classification I-III.
• Undergoing hip surgery under spinal anesthesia.

Exclusion criteria

• Patient refusal.
• History of mental illness or scoring less than 8 using abbreviated mental test before operation as in table 3 .
• Obvious sinus bradycardia (heart rate of <50 beats per minute) or other serious cardiovascular diseases.
• Symptomatic cerebrovascular disease (such as previous stroke).
• History of liver and kidney dysfunction.
• Allergy to lidocaine or ketamine.
• Metabolic disorders and fluid, electrolytes disturbances.
• Alcohol dependence or drug abuse.
• Redo surgery or infectious complications.
• Central nervous system medications (antipsychotics, anticonvulsants, antiparkinsonian, antidepressants).
• History of deep vein thrombosis.