title: Influence of anticholinesterase on distribution of ventilation and gas exchange.
abstract: This project was designed to titrate the influence of pyridostigmine injected intraarterially on pulmonary resistance and gas exchange in pigs and dogs. Pyridostigmine at 1 mg/kg reduced red blood cell cholinesterase activity 28-35% that was not significantly reduced further with doses up to 9 mg/kg. Plasma cholinesterase was reduced by 80% in the dog and 40% in the pig with 1 mg/kg of pyridostigmine and with 3 mg/kg it was reduced to 40% in the pig and 10% in the dog. Higher doses had no further significant effect. Breathing resistance (cm H2O/l/s) in the pig was doubled as a linear function with 9 mg/kg pyridostigmine. In the dog, breathing resistance went to a maximum of 8 cm H2O/l/s from a control value of 1 cm H2O/l/s with 3 mg/kg of pyridostigmine but did not go higher with doses up to 9 mg/kg. PaO2 was reduced by approximately 20% in the pig and 15% in the dog with pyridostigmine doses of 6-9 mg/kg. These experiments indicate that significant alterations in pulmonary function do not occur until acute dosages in the range of 3-6 mg/kg are reached. Furthermore, acute administration of large doses of pyridostigmine results in salivation and gastrointestinal stimulation well in advance of any impairment of respiratory function.
authors.affiliation: Virginia Mason Research Center, Seattle, WA 98101.
authors.forename: H I
authors.initials: HI
authors.lastname: Modell
mesh_terms: D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D016084:Bronchoconstriction / Q000502:physiology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D002802:Cholinesterases / Q000097:blood; D004285:Dogs; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D008297:Male; D010100:Oxygen / Q000097:blood; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D012119:Respiration / Q000187:drug effects*; D013552:Swine
chemical_list: D002800:Cholinesterase Inhibitors; D002802:Cholinesterases; D010100:Oxygen