Evaluation of Nitrous Oxide in the Gas Mixture for... (Phase 4) — Recruiting Now

Conditions

The effect of Nitrous Oxide on endothelial function for patients having elective surgery of 2 hour or more duration.

Summary

Patients consenting to the trial will have baseline and day 1 postoperative measurements of their endothelial functioning on one arm. Preoperatively : A blood pressure cuff is inflated on the upper arm and an ultrasound is taken of the blood vessels in the arm as the cuff is deflated. Blood tests are taken for folate, homocysteine, arginine, citrulline, ADMA and nitrate. Intraoperatively : Patients will be randomly allocated to either 70% N2O in oxygen (FiO2 0.3) or oxygen with or without nitrogen (FiO2 0.8-1.0). Postoperatively : Patients will have the ultrasound on the same arm as preoperatively and blood tests will be done again. Half of the patients will have received nitrous oxide for a minimum of 2 hours and the other half only oxygen.

Eligibility

Sex: Both males and femalesMin Age: 18 Yearss

Inclusion Criteria1

Any risk factors for arteriosclerosis (eg. hypertension, diabetes, age >60 yrs, coronary artery disease). 2. Planned general anaesthesia for surgery that includes a skin incision and expected to exceed two hours, and the patient is expected to be in hospital for at least three days.

Exclusion Criteria1

Endoscopic or radiological procedures 2. Cardiac surgery3. Marked impairment of gas-exchange (requiring Fi02> 0.3)4. Thoracic surgery requiring one-lung ventilation (requiring Fi02> 0.3)5. Specific circumstances where N2O is contraindicated (eg. volvulus, pulmonary hypertension, raised intracranial pressure)6. Lack of provision of N2O.7. Patients considered to be at high-risk for PONV8. Patients considered to be at high-risk for wound infection.

Interventions

Patients consenting to the trial will have baseline and day 1 postoperative measurements of their endothelial functioning on one arm. Preoperatively : A blood pressure cuff is inflated on the uppe

Patients consenting to the trial will have baseline and day 1 postoperative measurements of their endothelial functioning on one arm. Preoperatively : A blood pressure cuff is inflated on the upper arm and an ultrasound is taken of the blood vessels in the arm as the cuff is deflated. Blood tests are taken for folate, homocysteine, arginine, citrulline, ADMA and nitrate. Intraoperatively : Patients will be randomly allocated to either 70% N2O in oxygen (FiO2 0.3) or oxygen with or without nitrogen (FiO2 0.8-1.0). Postoperatively : Patients will have the ultrasound on the same arm as preoperatively and blood tests will be done again. Half of the patients will have received nitrous oxide for a minimum of 2 hours and the other half only oxygen.

Locations(1)

Australia

Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia