Effect of Low Flow Anesthetics on Neurocognitive Decline in the Elderly

Study Overview
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Brief Summary
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This study aims to investigate the effect of inhaled anesthetics with a low fresh gas flow on cognitive function of elderly patients undergoing elective surgery

Detailed Description
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Geriatric patients scheduled to undergo surgery were tested with Mini Mental State Examination (MMSE) in the preoperative visit. MMSE was repeated postoperatively at the 6th hour, the 1st, 3rd, and 7th day. Visual analogue scale (VAS) test was performed simultaneously on the postoperative 6th hour, the 1st, 3rd, and 7th day. Two cohorts were created according to the amount of fresh gas flow (low flow vs high flow) in the maintenance phase of the inhalational anesthetic. MMSE scores were compared between cohorts and baseline. VAS scores were compared between cohorts.

Official Title
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Effect of Low Fresh Gas Flow Volatile Anesthetics on Postoperative Neurocognitive Function in Elderly Patients

Conditions
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Neurocognitive Disorders, Inhalation; Vapor

Intervention / Treatment
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* Other: General anesthesia with low fresh gas flow
* Other: General anesthesia with high fresh gas flow
* Diagnostic Test: Mini mental state examination
* Diagnostic Test: Visual Analogue Scale


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age>65 Consenting to participate Scheduled for surgery longer than 2 hours under GA Able to read and write Exclusion Criteria: Age<65 Refusing to participate Existing visual impairment preventing the patient from reading or writing Unable to read and write Existing major neurocognitive disorder Use of TIVA or regional techniques Allergies to the volatile agents Uncontrolled DM, acute alcohol intoxication Conditions increasing tissue oxygen consumption (sepsis, thyrotoxicosis, etc.) Anticipation/existence of major hemorrhage Haemodynamic instability > 10 min or more than 5 times intraoperatively

Ages Eligible for Study
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Minimum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| High flow cohort (HFA)<br>Patients, whose maintenance phase of anesthesia is managed with a fresh gas flow ≥ 1L/min, were included in this cohort. | Other: General anesthesia with high fresh gas flow<br>* General anesthesia with a fresh gas flow equal to or higher than 1L/min for the maintenance phase of anesthesia<br>Diagnostic Test: Mini mental state examination<br>* 6 category and 30-point test to inquire patient's cognitive function<br>* Other names: MMSE;Diagnostic Test: Visual Analogue Scale<br>* The patient's self-reported pain intensity according to a visual scale between 0 and 100<br>* Other names: VAS;|
| Low flow cohort (LFA)<br>Patients, whose maintenance phase of anesthesia is managed with a fresh gas flow < 1L/min, were included in this cohort. | Other: General anesthesia with low fresh gas flow<br>* General anesthesia with a fresh gas flow lower than 1L/min for the maintenance phase of anesthesia<br>Diagnostic Test: Mini mental state examination<br>* 6 category and 30-point test to inquire patient's cognitive function<br>* Other names: MMSE;Diagnostic Test: Visual Analogue Scale<br>* The patient's self-reported pain intensity according to a visual scale between 0 and 100<br>* Other names: VAS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in neurocognitive status on the 30 point MMSE at postoperative 24th hour | A Mini-Mental State Examination (MMSE) is a set of 11 questions that doctors and other healthcare professionals commonly use to check for cognitive impairment (problems with thinking, communication, understanding and memory). | Baseline and postoperative day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in neurocognitive status on the 30 point MMSE at postoperative 6th hour | A Mini-Mental State Examination (MMSE) is a set of 11 questions that doctors and other healthcare professionals commonly use to check for cognitive impairment (problems with thinking, communication, understanding and memory). | Baseline and postoperative hour 6 | 
| Change from baseline in neurocognitive status on the 30 point MMSE at postoperative 3rd day | A Mini-Mental State Examination (MMSE) is a set of 11 questions that doctors and other healthcare professionals commonly use to check for cognitive impairment (problems with thinking, communication, understanding and memory). | Baseline and postoperative day 3 | 
| Change from baseline in neurocognitive status on the 30 point MMSE at postoperative 7th day | A Mini-Mental State Examination (MMSE) is a set of 11 questions that doctors and other healthcare professionals commonly use to check for cognitive impairment (problems with thinking, communication, understanding and memory). | Baseline and postoperative day 7 | 
| Change from baseline in pain on the 10 point VAS scale at postoperative 6th hour | The visual analog scale (VAS) is a tool widely used to measure pain. A patient is asked to indicate his/her perceived pain intensity (most commonly) along a 100 mm horizontal line, and this rating is then measured from the left edge | Baseline and postoperative hour 6 | 
| Change from baseline in pain on the 10 point VAS scale at postoperative 24th hour | The visual analog scale (VAS) is a tool widely used to measure pain. A patient is asked to indicate his/her perceived pain intensity (most commonly) along a 100 mm horizontal line, and this rating is then measured from the left edge | Baseline and postoperative hour 24 | 
| Change from baseline in pain on the 10 point VAS scale at postoperative 3rd day | The visual analog scale (VAS) is a tool widely used to measure pain. A patient is asked to indicate his/her perceived pain intensity (most commonly) along a 100 mm horizontal line, and this rating is then measured from the left edge | Baseline and postoperative day 3 | 
| Change from baseline in pain on the 10 point VAS scale at postoperative 7th day | The visual analog scale (VAS) is a tool widely used to measure pain. A patient is asked to indicate his/her perceived pain intensity (most commonly) along a 100 mm horizontal line, and this rating is then measured from the left edge | Baseline and postoperative day 7 |