Short term olfactory memory and olfactory function after inhalation anesthetic agents: a randomized clinical trial

Sarı, Hüseyin; Atar, Yavuz; Mingir, Tarkan; Kumral, Tolgar Lütfı; Akgun, Muhammed Fatih; Ahmed, Esmail Abdulahi; Aydoğdu, İmran; Saltürk, Zıya; Berkıten, Güler; Uyar, Yavuz

doi:10.1016/j.bjane.2020.02.009

Cited by 5 publications

(6 citation statements)

References 21 publications

(21 reference statements)

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“…Although we used an olfactory identification test, this age effect could contribute to the greater postoperative decline in our older cohort. Overall, we show a decrease in median olfactory identification score on the first postoperative day, which corroborates existing studies showing similar results either at 3 hours [ 9 – 11 ] or, using the discrimination modality, within 15 hours [ 12 ] postoperatively. In two of them, olfactory results were retested again at least 3 days postoperatively and came back to baseline [ 10 , 11 ].…”

Section: Discussionsupporting

confidence: 91%

Poor preoperative performance at Clock Drawing Test is associated with postoperative decline in olfaction in older patients: an observational pilot study

Van Regemorter,

Coulie,

Dollase

et al. 2023

BMC Anesthesiol

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Background Decline in olfaction may occur after general anesthesia, but the exact incidence and underlying physiopathology remain scarcely investigated. Olfactory dysfunction arises with aging and is known to be linked to cognitive impairment. In this pilot study, we evaluated the incidence of immediate postoperative decline in olfaction and its association with a preoperative cognitive test, performance at Clock Drawing Test (CDT), in a group of older patients. Methods This pilot study is a sub-analysis of a prospective observational study. Patients ≥ 65 years old and scheduled for elective non-cardiac surgery under sevoflurane-based anesthesia were enrolled. CDT was part of the preoperative evaluation. We assessed olfaction on the day before and the day after surgery (between 16 and 26 h postoperatively) using the Sniffin’ Sticks 12-item identification test, which consists of pen-like devices displaying 12 different odors. Postoperative decline in olfaction was defined as a decrease of at least 1 standard deviation in the olfactory score. Results We included a total of 93 patients, among whom 19 (20.4%) presented a postoperative decline in olfaction. The incidence of postoperative decline in olfaction was higher in the “CDT low-score” (score ≤ 5/8) group (11/34, 32.4%) than in the “CDT high-score” (score ≥ 6/8) group (8/58, 13.6%) (P = 0.030). Despite adjusting for confounding variables, CDT score remained independently associated with immediate postoperative decline in olfactory identification function (OR 0.67, 95% CI 0.48 to 0.94, P = 0.022). Conclusions Postoperative decline in olfaction occurred in 20.4% of older patients and was associated with poor preoperative performance at CDT. Trial registration This study was retrospectively registered on https://clinicaltrials.gov/ under the NCT04700891 number (principal investigator: Victoria Van Regemorter), in December 2020.

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Section: Discussionsupporting

confidence: 91%

Poor preoperative performance at Clock Drawing Test is associated with postoperative decline in olfaction in older patients: an observational pilot study

Van Regemorter,

Coulie,

Dollase

et al. 2023

BMC Anesthesiol

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“…There are only a few published articles about changes in olfaction related to anesthesia, and most of these are case reports or letters to editors. Some have attempted to determine the effect of anesthesia in controlled studies, however, only transient effects were noted at best 30 , 33 . There has been no clear causality or pathophysiology for these phenomena.…”

Section: Discussionmentioning

confidence: 99%

“…There have also been several reports on effects of anesthesia 27 on olfaction. Most reports involve general anesthesia 21 – 24 , 26 , 28 – 30 , however, there are a few citing spinal anesthesia 3 , 31 , intravenous 25 , and topical anesthesia 28 , 32 , 33 to also have effects on olfaction. The rarity of such events may also mean that these cases are underreported.…”

Section: Introductionmentioning

confidence: 99%

Olfactory function testing before and after anesthesia

Hernandez

Fuchss

Haehner

et al. 2021

Sci Rep

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This study aimed to determine whether anesthesia would affect olfactory function. Patients who were admitted for surgical intervention that did not include the nasal cavity and paranasal sinuses were included in this prospective cohort study. Structured medical history was taken from the patients, including the following: age, sex, smoking history, alcohol intake, current medications, and sleep deficits prior to surgery. Before surgery, patients were asked for a self-rating of their olfactory function. Olfactory function was also measured using Sniffin’ Sticks comprising measures of odor threshold, discrimination, and identification. The mean interval between olfactory tests was 6 days (range 3–12 days). Seventy-three patients were included in the study, 34 men and 39 women. Olfactory scores were consistent before and after surgery as indicated by correlative analyses (p < 0.05). Odor thresholds, discrimination, identification, and composite TDI scores did not change significantly, whereas odor identification scores increased (p = 0.011) after surgery. In conclusion, post-operative olfactory scores remained stable. However, identification scores exhibited a slight increase which can be attributed to a retest effect. Overall, the present results indicate that surgery outside of the nasal and paranasal sinus region performed in general anesthesia has no major effect on the sense of smell.

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“…These studies have shown that the loss of neurons in the olfactory bulb is a crucial cause of olfactory cognitive dysfunction. The importance of olfactory cognitive function lies in its significant influence in other social behaviors, including personality, sexual behavior and interpersonal communication (Sari et al, 2020). Once abnormalities in olfactory cognitive function occur, they may lead to severe psychiatric disorders, such as depression, schizophrenia, and olfactory cognitive dysfunction (Schinder and Gage, 2004;Apple et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Dexmedetomidine alleviates olfactory cognitive dysfunction by promoting neurogenesis in the subventricular zone of hypoxic-ischemic neonatal rats

Chen

Deng

et al. 2022

Front. Pharmacol.

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Background: Hypoxic-ischemic brain damage (HIBD) is the main cause of neurological dysfunction in neonates. Olfactory cognitive function is important for feeding, the ability to detect hazardous situations and social relationships. However, only a few studies have investigated olfactory cognitive dysfunction in neonates with HIBD; furthermore, the specific mechanisms involved are yet to be elucidated. It has been reported that neurogenesis in the subventricular zone (SVZ) is linked to olfactory cognitive function. Recently, dexmedetomidine (DEX) has been shown to provide neuroprotection in neonates following HIBD. In the present study, we investigated whether DEX could improve olfactory cognitive dysfunction in neonatal rats following HIBD and attempted to determine the underlying mechanisms.Methods: We induced HIBD in rats using the Rice–Vannucci model, and DEX (25 μg/kg, i.p.) was administered immediately after the induction of HIBD. Next, we used triphenyl tetrazolium chloride (TTC) staining and the Zea-longa score to assess the success of modelling. The levels of BDNF, TNF-α, IL-1β and IL-6 were determined by western blotting. Immunofluorescence staining was used to detect microglial activation and microglial M1/M2 polarization as well as to evaluate the extent of neurogenesis in the SVZ. To evaluate the olfactory cognitive function, the rats in each group were raised until post-natal days 28–35; then, we performed the buried food test and the olfactory memory test.Results: Analysis showed that HIBD induced significant brain infarction, neurological deficits, and olfactory cognitive dysfunction. Furthermore, we found that DEX treatment significantly improved olfactory cognitive dysfunction in rat pups with HIBD. DEX treatment also increased the number of newly formed neuroblasts (BrdU/DCX) and neurons (BrdU/NeuN) in the SVZ by increasing the expression of BDNF in rat pups with HIBD. Furthermore, analysis showed that the neurogenic effects of DEX were possibly related to the inhibition of inflammation and the promotion of M1 to M2 conversion in the microglia.Conclusion: Based on the present findings, DEX treatment could improve olfactory cognitive dysfunction in neonatal rats with HIBD by promoting neurogenesis in the SVZ and enhancing the expression of BDNF in the microglia. It was possible associated that DEX inhibited neuroinflammation and promoted M1 to M2 conversion in the microglia.

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Short term olfactory memory and olfactory function after inhalation anesthetic agents: a randomized clinical trial

Cited by 5 publications

References 21 publications

Poor preoperative performance at Clock Drawing Test is associated with postoperative decline in olfaction in older patients: an observational pilot study

Poor preoperative performance at Clock Drawing Test is associated with postoperative decline in olfaction in older patients: an observational pilot study

Olfactory function testing before and after anesthesia

Dexmedetomidine alleviates olfactory cognitive dysfunction by promoting neurogenesis in the subventricular zone of hypoxic-ischemic neonatal rats

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