Interaction of Cobalamin Status With Nitrous Oxide in Relation to Postoperative Cognitive Changes in the Elderly
Public ClinicalTrials.gov record NCT00212147. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
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Official title
Subtle Disturbances of Cobalamin Status
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
Low cobalamin (vitamin B12) levels are frequent in the elderly. Most often they reflect a mild metabolic abnormality without clinical symptoms (subclinical cobalamin deficiency). It is unclear if these elderly people require medical intervention, unlike that small minority with clinical symptoms which can progress and create severe blood or nervous system problems. The study aims to determine if nitrous oxide (N2O), a common anesthetic agent, worsens cobalamin status in elderly patients with unrecognized subclinical cobalamin deficiency. The reason for concern is that N2O inactivates cobalamin and can aggravate the clinical picture of patients who already have clinical manifestations of cobalamin deficiency. The elderly are known to have an increased risk of developing mental changes after surgery and it may be that sometimes these result from aggravation of subclinical cobalamin deficiency. The study recruits people over the age of 60 years who are undergoing clinically indicated elective surgery requiring general anesthesia for more than 1 hour. Patients meeting exclusion and inclusion criteria are randomized to receive either a standard anesthetic regimen that includes N2O or a nearly identical one without N2O. Before surgery and 2 weeks and 4 weeks after surgery, each patient undergoes (1) a broad battery of tests of cognition and mood and (2) blood tests measuring cobalamin, folate and homocysteine-methionine metabolism to determine whether they have any subtle biochemical impairment of cobalamin status. DNA from blood cells is also tested for the presence of common mutations that affect key enzymes in those metabolic pathways. A brief testing for postoperative delirium is also done 2 hours after surgery. The patient subgroups' are analyzed for neuropsychologic changes over time, using the preoperative test as the baseline for all comparisons, and associations of those changes with metabolic, genetic, demographic and clinical data. The primary question is what effect routine N2O exposure has on the latter compared with non-N2O anesthesia in elderly people who either have or do not have subclinical cobalamin deficiency. It will help answer whether or not the combination can help explain the increased risk of cognitive problems after surgery in elderly patients, and by extension whether preoperative cobalamin testing and treatment may be indicated in the elderly. It will also test whether genetic predisposition affects the described problems.
Study identification
- NCT ID
- NCT00212147
- Recruitment status
- Completed
- Study type
- Interventional
- Phase
- Not applicable
- Enrollment
- 444 participants
Conditions and interventions
Interventions
Drug
Eligibility (public fields only)
- Age range
- 60 Years and older
- Sex
- All
- Healthy volunteers
- Healthy volunteers not accepted
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Aug 31, 2003
- Primary completion
- Jul 31, 2008
- Completion
- Jul 31, 2008
- Last update posted
- Aug 7, 2022
2003 – 2008
United States locations
- U.S. sites
- 2
- U.S. states
- 1
- U.S. cities
- 2
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| New York Methodist Hospital | Brooklyn | New York | 11215 | — |
| WeillMedical College of Cornell University | New York | New York | 10021 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT00212147, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Aug 7, 2022 · Synced Sep 7, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT00212147 live on ClinicalTrials.gov.