Evaluation Of Preoperative Nebulized Dexmedetomidine for the prevention of postoperative delirium in elderly patients undergoing surgery under general anesthesia - A Randomized Control Trial

Post operative mental and behavioral abnormalities are generally divided into three situations: Emergence delirium, Post operative delirium and post operative cognitive dysfunction (1). Postoperative delirium (POD) is a common and significant complication, characterized by acute disturbances in attention, awareness, and cognition, typically occurring between postoperative days 1 and 5. (2). Surgical trauma, anesthesia, pain, disturbances in sleep patterns, changes in nutrition and delirium-inducing drugs such as high-dose narcotics, benzodiazepines and anticholinergics further contribute to the development of neurocognitive insults particularly in high-risk patients. Patients over 60 years old and those with preexisting conditions such as dementia, cardiovascular disease, diabetes and anemia are particularly vulnerable. POD can prolong recovery times, delayed discharge from the ICU and increase hospital stays overall affecting functional independence & quality of life. So, effective prevention of post operative delirium not only enhances patient safety and recovery but also reduces health care costs.

The pathophysiology of postoperative delirium (POD) is believed to be multifactorial, involving neuroinflammation, systemic stress responses, and micro emboli or watershed strokes. (4). Dexmedetomidine exerts its neuroprotective effects through multiple mechanisms primarily via selective alpha2-adrenergic receptor agonism, by reducing norepinephrine release. This leads to its both analgesic and sedative properties. It also reduces the release of substance P and mitigates nociceptive signaling. Dexmedetomidine interacts with imidazoline type 2 (I2) receptors potentially regulating calcium levels and mitigating endoplasmic reticulum stress-induced apoptosis which may protect against neuronal damage. It modulates neurotransmitter pathways and studies show that patients treated with dexmedetomidine has limited decrease in acetylcholinesterase (Ache) and butyrylcholinesterase (B.Ch.E.) activity. This limits inflammation and the systemic stress response to surgical trauma. (5)

Several drugs, including melatonin, ramelteon, acetaminophen, neostigmine and corticosteroids, are being studied for preventing postoperative delirium, but dexmedetomidine has the strongest evidence supporting its effectiveness in prevention of POD. (6)

However, there is limited research on the use of nebulized dexmedetomidine for preventing post operative delirium in adults. Therefore, this study aims to assess the efficacy of preoperative dexmedetomidine nebulization in preventing post operative delirium in elderly patients undergoing surgeries under general anesthesia.