title: Reversal of nitrous oxide-induced depression of hypoxic pulmonary vasoconstriction by lignocaine hydrochloride during collapse and ventilation hypoxia of the left lower lobe.
abstract: The blood flow to the left lower lobe (QL), and total (QT) pulmonary blood flow, were measured in 10 open-chest dogs using electromagnetic flowmeters. Ventilation of the left lower lobe with 7% oxygen in nitrogen produced a greater reduction in QL/QT (41%) than lobar ventilation with 7% oxygen in nitrous oxide (33%). Lobar collapse reduced QL/QT by 65%, but there was no change in QL/QT when 50% nitrous oxide was administered to the right lung. The i.v. infusion of lignocaine hydrochloride during ventilation of the lobe with 7% oxygen in nitrogen produced no change in QL/QT. However, lignocaine infusion during lobar ventilation with 7% oxygen in nitrous oxide produced a further reduction in QL/QT to a value which was not significantly different from that observed during ventilation with 7% oxygen in nitrogen. Lignocaine had no effect on QL/QT during lobar collapse whether the right lung was ventilated with 50% oxygen in nitrogen or 50% oxygen in nitrous oxide. It is concluded that lignocaine reverses the depression of hypoxic pulmonary vasoconstriction produced by lobar ventilation with nitrous oxide.
mesh_terms: D000818:Animals; D001794:Blood Pressure; D003864:Depression, Chemical; D004285:Dogs; D008012:Lidocaine / Q000494:pharmacology*; D008168:Lung / Q000098:blood supply*; D009609:Nitrous Oxide / Q000494:pharmacology*; D010100:Oxygen / Q000502:physiology*; D001261:Pulmonary Atelectasis / Q000503:physiopathology; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D008012:Lidocaine; D009609:Nitrous Oxide; D010100:Oxygen