BACKGROUND There is a plausible pathophysiologic rationale for increased long-term cardiovascular morbidity and mortality in patients receiving significant exposure to nitrous oxide. However, this relationship has not been established clinically. The ENIGMA trial randomized 2050 patients having noncardiac surgery lasting more than 2 hours to nitrous oxide-based or nitrous oxide-free anesthesia....

BACKGROUND Globally there are >200 million major surgical procedures undertaken annually, and about 20% of these involve patients who have coronary artery disease. Many receive nitrous oxide, which impairs methionine synthase, thus inhibiting folate synthesis and increasing postoperative homocysteine levels. Nitrous oxide anesthesia leads to postoperative endothelial dysfunction, and there is s...

BACKGROUND Nitrous oxide limits intraoperative hypothermia because the vasoconstriction threshold with nitrous oxide is higher than with equi-minimum alveolar concentrations of sevoflurane or isoflurane, presumably because of its stimulating actions on the sympathetic nervous system. Xenon, in contrast, does not cause sympathetic activation. Therefore, the authors tested the hypothesis that the...

BACKGROUND Even the best cancer surgery is usually associated with minimal residual disease. Whether these remaining malignant cells develop into clinical recurrence is at least partially determined by adequacy of host defense, especially natural killer cell function. Anesthetics impair immune defenses to varying degrees, but nitrous oxide appears to be especially problematic. We therefore test...

Due to the present evidence for reproductive toxicity of nitrous oxide (N(2)O) among female personnel in health care, exposure of 17 female workers employed in two post-anesthesia care units was evaluated. Geometric mean concentration of nitrous oxide for six recovery room personnel was 3.1 ppm versus 1.17 ppm for eleven employees in surgical nursing units. The longest time needed to reach zero...

Adverse effects may occur when patients with air in the pleural space or in the cerebral ventricles breathe nitrous oxide. We developed an animal model to learn whether similar adverse effects are associated with the inhalation of nitrous oxide when air is present in the subcutaneous space. We induced extensive subcutaneous emphysema in swine and measured oxygen and carbon dioxide tensions in s...

The effect of halothane or nitrous oxide or both, on division of cultured, murine bone-marrow cells was investigated. Halothane caused a dose-dependent depression of growth rate ranging from a minimal effect at 0.5% to almost total inhibition at 2.0%. Nitrous oxide 75% had an effect similar to 0.5% halothane and the combination of 0.75% halothane with 75% nitrous oxide produced results little d...

The effect of in vitro exposure to nitrous oxide on rat fetal and maternal methionine synthase activity was investigated. Enzyme solutions were prepared from livers of fetuses and mothers on day 19 of gestation and exposed to air, 50% oxygen or 50% nitrous oxide in oxygen for periods up to 24 h. Normal activity of methionine synthase in the fetus was about 65% of that in the mother. Activity de...

We have investigated the effects of fentanyl, nitrous oxide, or both, on carotid sinus baroreceptor reflexes in cats during basal chloralose anaesthesia. The bilaterally isolated carotid sinuses were perfused at prevailing systemic arterial pressure or at predetermined levels of pump-controlled pulsatile pressures of 50-200 mm Hg in steps of 25 mm Hg. Other major baroreceptor sites were denerva...

The mutagenic potential of halothane, enflurane and isoflurane in combination with nitrous oxide was investigated using the sex-linked recessive lethal assay in the fruit fly Drosophila melanogaster. Male wild-type flies were exposed for 1 h to 1 or 2% volatile anaesthetic with various concentrations of nitrous oxide up to 75%. They were then mated with untreated females of the Basc marker stra...