Effects of Premedicant Drugs on Respiration and Gas Exchange in Man

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Abstract
The effects on pulmonary function of atropine, scopolamine, morphine, and a synthetic narcotic, AN-2227, were studied in a controlled double-blind randomized experiment. Atropine and scopolamine (0. 5 mg each) produced minimal changes except for a 22 to 25% increase in the respiratory dead space. Compensatory increase in minute volume kept CO2 tension approximately the same. Alveolar ventilation was unaffected. The respiratory response to increased CO2 was insignificantly affected by either atropine or scopolamine. O2 consumption and CO2 production were unchanged. Morphine sulfate, 10 mg, and AN-2227, 4 mg increased end-tidal CO2 tension significantly and decreased alveolar ventilation 9% and 22% respectively. Respiratory response to CO2 inhalation was significantly reduced by both morphine and the new nar -cotic, evidenced by displacements of 6 and 9 torr, respectively, in the CO2 response curve. Smaller doses of AN-2227 depressed respiration to a lesser extent, with 2 mg of the new narcotic being equidepressant with 10 mg morphine. On consuption and CO2 production did not change significantly, and lung volumes were unaffected.