title: The effect of pregnancy on pulmonary nitrogen washout. A study of pre-oxygenation.
abstract: Pre-oxygenation times were studied in 30 fit pregnant women during the course of their pregnancy. The mothers were studied in the supine position with a left lateral tilt and breathing through a standard Magill system with an oxygen flow rate of 8 litres/minute. Between 13-26 weeks gestation and 26-42 weeks the times needed to achieve an end-tidal nitrogen of 2% were 104 seconds (SD 30) and 80 seconds (SD 20), respectively. A control group of young women of similar age and weight needed 130 seconds (SD 30) to achieve the same end-tidal nitrogen concentration. A gas-tight mask was found to be essential to achieve effective denitrogenation (end-tidal nitrogen concentration of 2%).
mesh_terms: D000328:Adult; D000773:Anesthesia, Obstetrical; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology*; D009584:Nitrogen; D010100:Oxygen / Q000008:administration & dosage* / Q000502:physiology; D011247:Pregnancy / Q000502:physiology*; D013997:Time Factors
chemical_list: D009584:Nitrogen; D010100:Oxygen