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NCT Number: NCT03726580

Evaluation of Neurotoxic Effect of Sevoflurane-Based AnaesthesiaGuided by Short-Term Olfactory Identification

Nowadays there is increasing doubts about the safety of anesthesia . Anesthesiologists have to console the worried patients, who are anxious about the potential risks of anesthetic-induced brain damage, by suggesting that any detrimental effects would be "mild".Anesthetics are responsible for postoperative taste and odor defects and cognitive dysfunction.

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Key information

Conditions

Neurotoxic Effect of Sevoflurane-Based Anaesthesia Anosmia Chemically-Induced Disorders Nervous System Diseases Neurologic Manifestations Neurotoxicity Syndromes Olfaction Disorders Pathological Conditions, Signs and Symptoms Poisoning Sensation Disorders Signs and Symptoms

Age range

60 year–75 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Ahmed Said Elgebaly

Tanta, Egypt

About this study

Aims: The aim of this study is to assess the effect of isoflurane, sevoflurane, propofol and regional anesthesia on the olfactory threshold, olfactory identification and endocrine regulation of associative memory in the postoperative period in old age group.

Methods: 600 patients (> 60years ) fulfilling the criteria of the American society of anesthesiologists and II status were selected for this prospective single-blinded randomized controlled study. Patients were randomized into one of four groups to receive regional anesthesia (control group), general anesthesia with sevoflurane, general anesthesia with isoflurane and total intravenous anesthesia with propofol.

Mini-Mental State Examination (MMSE), olfactory threshold, and olfactory identification were tested at 12 hours preoperatively (T0), at 3 hours postoperatively (T1) and at the time of discharge or postoperative 3 days (T2). In addition, serum melatonin levels were estimated at T0 and T1.

N-butyl alcohol was used to test the olfactory threshold and the Pocket Smell Test TM series (PSTs) was used to test olfactory identification. Data were analyzed using the one-way analysis of variance, Kruskal-Wallis or Mann-Whitney tests.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • American Society of Anaesthesiologists I and II physical status
  • aged from 60 to 75years
  • scheduled for elective surgery with the anticipated duration of 100-120 min.
  • surgical procedures included hernia repair,
  • varicose vein surgery,
  • incisional hernia repair,
  • minor gynecological procedures,
  • lower limb orthopedic procedures,
  • minor urological procedures

Exclusion criteria

  • Patients with recent airway infection,
  • allergic rhinitis,
  • nasal polyps,
  • history of alcoholism,
  • smoking,
  • mental retardation,
  • psychiatric illness,
  • neurosurgical or oto-rhino-laryngeal surgery
  • patients with a history of olfactory deficits and cognitive impairment

Treatment and study plan

Sevoflurane

Drug

Assess the effect of isoflurane, sevoflurane, propofol and regional anesthesia on the olfactory threshold, olfactory identification and endocrine regulation of associative memory in the postoperative period in old age group.

Other names: Isoflurane, Propofol

Primary outcomes

  1. The changes in Mini-Mental State Examination (MMSE)

    Time frame: basically at 12 hours preoperatively (T0), then 3 hours postoperatively (T1) and at the time of discharge or postoperative 3 days (T2)

    Cognitive function evaluated by MMSE scores. The Mini-Mental State Examination (MMSE) or Folstein test is a 30-point questionnaire that is used extensively in clinical and research settings to measure cognitive impairment. It is commonly used in medicine and allied health to screen for dementia.

  2. The changes in olfactory threshold

    Time frame: basically at 12 hours preoperatively (T0), then 3 hours postoperatively (T1) and at the time of discharge or postoperative 3 days (T2)

    Was measured using serial dilutions (10 dilutions) of 4% n-butyl alcohol in deionized water. The test consists of 10 steps. In each step, the odorant and a blank were presented to the participant. The test progressed from weaker-to-stronger concentrations of odorant. Two bottles were presented to each participant, an odorant bottle and an identical bottle filled with distilled water. The participant sniffed each one for approximately 9 s and then chose which one smelled stronger. If the participant was incorrect at one concentration, the next higher concentration was presented. When the correct choice was made, the same concentration of odorant was presented to the participant until four consecutive correct responses were given. The threshold was defined as the butyl alcohol concentration correctly chosen over water in four consecutive trials, and the corresponding number of the concentration was taken as the threshold value.

  3. The changes in olfactory identification

    Time frame: basically at 12 hours preoperatively (T0), then 3 hours postoperatively (T1) and at the time of discharge or postoperative3 days (T2)

    Was assessed using the Pocket Smell TestTM series (PSTs). The test uses four booklets containing labels impregnated with odorous substances. The test is in multiple-choice format, with four written response alternatives for each odor. The odors are released when the labels are scratched. The examiner scraped each target patch and instructed participants to smell the patch and then select the name of the released odor from among four alternatives. Olfactory identification tested using the (PSTs) assessed both the recent memory and the remote memory of the patient as it contained odors which were a mixture of both the familiar and unfamiliar ones to the study population. Here, it is not utilized to identify patients with anosmia or hyposmia. Instead, the (PSTs) is used as a linear, unbiased unidimensional Rasch measure of human smell recognition abilities.

Secondary outcomes

  1. The changes in olfactory melatonin levels

    Time frame: serum melatonin levels were estimated basically at 12 hours preoperatively (T0), then 3 hours postoperatively (T1) and at the time of discharge or postoperative3 days (T2)

    Melatonin levels were measured in plasma by the enzyme-linked immunosorbent assay (ELISA) (IBL, Hamburg, Germany).

Sponsors and collaborators

Lead sponsor

Tanta University

Other

Collaborators

  • Amer Galal Younis,MD

Registry information

Official study title

Evaluation of Neurotoxic Effect of Sevoflurane-Based Anaesthesia Guided by Significant Short-Term Olfactory Identification Impairment in Old Age

Important dates

Study start
2017
Primary completion
2018
Study completion
2018
First posted
Oct 31, 2018
Registry last updated
Nov 1, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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