Homocysteine After Nitrous Oxide Anesthesia

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE4

Total Enrollment

140 participants

Study Classification

INTERVENTIONAL

Study Start Date

2005-01-31

Study Completion Date

2007-03-31

Brief Summary

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Our study looks at the interaction of a common mutation in the MTHFR gene and the risk of developing higher homocysteine levels after nitrous oxide (N2O) anesthesia.

Specifically, we want to test the hypothesis that healthy patients carrying the MTHFR 677C\>T haplotype develop abnormal homocysteine levels after nitrous oxide anesthesia.

Detailed Description

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Nitrous oxide - laughing gas - is a widely used anaesthetic gas with many favourable but also some dangerous properties. Among the latter is the increase in homocysteine levels after nitrous oxide (N2O) exposure by inhibition of enzymes in the vitamin B12 pathway. Elevated homocysteine levels have been found to be an independent risk factor for ischemic events and are associated with an increased risk for perioperative myocardial ischemia. If a patient carries one or more loss-of-function mutations in enzymes of the methionine/homocysteine/folate pathway he is at an increased risk for hyperhomocysteinemia and if exposed to N2O might suffer severe, sometimes disastrous neurological damage. Recently, a case report in the New England Journal of Medicine reported the death of a child with an enzyme defect in the MTHFR gene after anaesthesia with nitrous oxide (NEJM 2003;349:45-50).

Thus, we are convinced that if we can determine the risk of patients who carry mutations in the MTHFR gene and undergo anaesthesia with N2O for developing pathological levels of homocysteine, we can add an important piece of information to the safety profile of N2O.

Our study tests the hypothesis that patients who carry the 677C\<T mutation in the MTHFR gene (the most common mutation) have a higher risk of developing hyperhomocysteinemia after N2O anaesthesia.

Conditions

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Anesthesia, General Adverse Effects Nitrous Oxide

Study Design

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Allocation Method

NA

Intervention Model

SINGLE_GROUP

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

NONE

Interventions

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Nitrous oxide

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Patient scheduled for general anaesthesia (\> 2 hours)
* Age \> 18 years
* ASA status I-II

Exclusion Criteria

* Pregnancy
* Age \< 18 years
* contraindication against N2O: pneumothorax, mechanical bowel obstruction, middle ear occlusion, laparoscopic surgery
* recent use of vitamin preps (B12, B6, folate)

Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Principal Investigators

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Peter Nagele, M.D.

Role: PRINCIPAL_INVESTIGATOR

Medical University of Vienna

Locations

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Dept of Anesthesiology, Medical University of Vienna

Vienna, , Austria

Site Status

Countries

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Austria

References

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Nagele P, Zeugswetter B, Eberle C, Hupfl M, Mittlbock M, Fodinger M. A common gene variant in methionine synthase reductase is not associated with peak homocysteine concentrations after nitrous oxide anesthesia. Pharmacogenet Genomics. 2009 May;19(5):325-9. doi: 10.1097/FPC.0b013e328328d54c.

Reference Type DERIVED

PMID: 19339913 (View on PubMed)

Nagele P, Zeugswetter B, Wiener C, Burger H, Hupfl M, Mittlbock M, Fodinger M. Influence of methylenetetrahydrofolate reductase gene polymorphisms on homocysteine concentrations after nitrous oxide anesthesia. Anesthesiology. 2008 Jul;109(1):36-43. doi: 10.1097/ALN.0b013e318178820b.