title: Arterial concentrations of nitrous oxide during intermittent patient-controlled inhalation of 50 percent nitrous oxide in oxygen (Entonox) during the first stage of labour.
mesh_terms: D000328:Adult; D000773:Anesthesia, Obstetrical; D005260:Female; D006801:Humans; D007743:Labor, Obstetric; D009609:Nitrous Oxide / Q000008:administration & dosage / Q000097:blood*; D010100:Oxygen; D011247:Pregnancy; D012119:Respiration; D013997:Time Factors; D014692:Ventilation-Perfusion Ratio
chemical_list: D009609:Nitrous Oxide; D010100:Oxygen