Although often felt to be relatively innocuous, nitrous oxide can have significant metabolic effects in settings of abnormal vitamin B12 and B12-related metabolism in children. These conditions can be genetic or environmental. Symptoms may not appear until days to weeks after exposure to nitrous oxide. Although overt genetic diseases are relatively uncommon, the implications of nitrous oxide in...

Extensive clinical use has now been made of the nitrous oxide test for the detection and localization of left-to-right circulatory shunts. On theoretical grounds the magnitude of such a shunt should be related to the systemic and pulmonary arteriovenous differences in nitrous oxide content measured early in the period of inhalation. In order to determine the validity of the nitrous oxide method...

Prolonged anaesthesia with nitrous oxide inactivates vitamin B12 and impairs DNA synthesis in bone marrow cells. The use of parenteral folinic acid in the prevention of these toxic effects has been studied in 11 patients, ventilated artificially with nitrous oxide in oxygen for 24 h. Bone marrow aspirates were performed before and after exposure to nitrous oxide. They were assessed morphologica...

Extensive clinical use has now been made of the nitrous oxide test for the detection and localization of left-to-right circulatory shunts. On theoretical grounds the magnitude of such a shunt should be related to the systemic and pulmonary arteriovenous differences in nitrous oxide content measured early in the period of inhalation. In order to determine the validity of the nitrous oxide method...

A method of gas analysis is described for estimating carbon dioxide in the presence of nitrous oxide, using a modified Lloyd-Haldane apparatus. Some of the sample, after scrubbing with soda-lime, bubbles through the potash and this eliminates the solubility effect of nitrous oxide by equilibrating the standard potash solution with nitrous oxide at the tension of the sample analysed and eliminat...

Since the late 1960s, investigators have assessed the risks associated with exposure to a variety of potentially harmful agents used in dental practice. This paper provides a brief overview of the epidemiologic literature examining the associations between occupational exposures to elemental mercury and anesthetic gases and reproductive outcomes, such as spontaneous abortion, congenital abnorma...

What does it take to get an established and effective but forgotten tool back into obstetric practice? In the case of nitrous oxide, it took a nurse-midwife. Nitrous oxide, also called laughing gas, is a colorless gas initially synthesized by the chemist JosephPriestly in 1772.1 In the late 1700s nitrous oxide was used recreationally to induce euphoria. It got the name laughing gas because user...

Peripheral vascular and myocardial effects of increasing concentrations of nitrous oxide (0 to 70 per cent) in oxygen were determined in 15 unanaesthetized calves before and after replacement in their natural heart (NH) with a pneumatically driven artificial heart (AH). Nitrous oxide produced concentration-related decreases in arterial and mixed venous pH and increases in minute ventilation and...

BACKGROUND Spectral entropy of the electroencephalogram (EEG) has been proposed to monitor anaesthetic depth. We investigated the effect of nitrous oxide on response (RE) and state entropy (SE) of the EEG during lumbar disc surgery under anaesthesia with sufentanil and sevoflurane. METHODS In an open study, anaesthesia was induced with propofol and sufentanil, and maintained with 2% end-tidal...

It is generally assumed that during denitrification bacteria oxidize organic substances completely to carbon dioxide concomitant with the reduction of nitrate or nitrite to nitrogen and nitrous oxide. This assumption is based upon the early experiments of Gayon and Dupetit (1886) which demonstrated that the ratio of carbon dioxide to nitrogen in denitrifying cultures corresponded to the theoret...