Desflurane Does not Affect Post-Operative Short-Term Olfactory Memory of Patients Undergoing Laparoscopic Surgery Introduction: a prospective clinical study

Background: The purpose of our study was to evaluate the effect of 6% desflurane on short-term olfactory memory after laparoscopic surgery, and to investigate whether plasma concentrations of plasma S-100β protein, neuron specific enolase (NSE) and melatonin correlate with it. Methods: : We collected medical data of patients who underwent laparoscopic surgery in the Second People's Hospital of Guiyang during May 2018 - February 2020. A total of 40 patients, who were aged 18-60 years old with American Society of Anesthesiologists (ASA) physical status I-II, were enrolled in the study. During the operation, the patients inhaled 6% desflurane to maintain the anesthesia. Patients were brought to the recovery room 45 minutes prior to the surgery (T 0 ). And the patients were sent to the post-anesthesia care unit (PACU) after the surgery, if their Aldrete score was ≥ 9 points (T 1 ), the CCCRC test was repeated to re-assess their olfactory memory. Venous blood samples (3 mL) were collected at T 0 and T 1 , and the plasma was centrifuged at 3,000 rpm and then stored in a refrigerator at -20°C. Plasma S-100β protein, NSE, and melatonin levels were determined using ELISA. Results: : There was no statistically significant difference in the odor identification score between T 0 and T 1 ( P > 0.05). As compared with T 0 , the plasma concentrations of S-100β protein and NSE declined at T 1 . However, these differences were not statistically significant ( P > 0.05). There were also no statistically significant changes in melatonin levels between T 0 and T 1 ( P > 0.05）. Conclusions: : This study found that undergoing general anesthesia with the inhaled anesthetic desflurane did not affect the short-term olfactory memory of patients undergoing laparoscopic surgery. This may be explained by the proposition that desflurane maintains plasma S-100β protein, NSE, and melatonin levels. Trial registration: Chinese Clinical Trial Registry (URL: http:// www.chictr.org.cn. Registry number: ChiCTR2100049441 ). Date of Registration: 2 August 2021.