Studies on cyclopropane; the effect of premedication with demerol upon the heart rate, rhythm and blood pressure in dogs under cyclopropane anesthesia.

1. An investigation of the blood pressure and electrocardiographic changes has been made in dogs anesthetized with cyclopropane after medication with Demerol. 2. In most dogs there is a reduction in heart rate and temporary fall in blood pressure after the intramuscular injection of 10 mg./kg. of Demerol. 3. The cardiac irregularities routinely observed during cyclopropane anesthesia after morphine premedication in dogs are not observed after Demerol premedication. 4. Demerol reduces the amount of cyclopropane necessary for the lighter planes of anesthesia.