Perioperative Salivary Alpha-amylase as a Predictor of Delirium After Lower Extremity Vascular Bypass Surgery

Delirium is a neuropsychiatric syndrome that is characterized by the sudden onset of altered awareness, decreased ability to maintain attention, and disorders of the mental process. The pathophysiology of Postoperative delirium (POD) is related to postoperative neuroinflammation.

Biomarkers not only indicate a certain pathological state, but also provide information about disease activity and progression. Although several biomarkers are reported to predict POD, biomarkers with high sensitivity and specificity are still lacking.

Biochemical parameters associated with complement cascade (C3a, C3, C5a) and inflammatory response (IL-17A, IL-33, E-selectin, MMP9) were involved in neurocognitive regulation.

Salivary alpha amylase (SAA) enzyme is one of the most important enzyme compositions in the saliva that accounts for 40% to 50% of the total salivary proteins, and most of it is secreted from the parotid gland. SAA is locally produced by the highly differentiated epithelial acinar cells of the exocrine salivary glands, mostly of the parotid glands and plays an important role in carbohydrate hydrolysis.

Inclusion criteria

• Age ≥ 65 years.
• Both sexes.
• American Society of Anesthesiologists (ASA) physical status III.
• Undergoing lower extremity vascular surgery under general anesthesia.

Exclusion criteria

• Patients who used any medication that could affect salivary glands (such as antihypertensive, antidepressants or antipsychotic drugs).
• Inability to communicate.
• History of psychiatric diseases or previous stroke
• Previous history of pod.
• Those with smoking and drinking habits.
• Pregnant female.