The effects of vascular catheterization upon heart rate and blood pressure before aorto-coronary bypass surgery

Ten patients presenting for aorto-coronary bypass surgery were premedicated with their regular dose of propranolol and nitrates and diazepam 0.15 mg x kg-1 by mouth, morphine 0.15 mg x kg-1 and scopolamine 0.4 mg intramuscularly, 60 to 90 minutes before arrival in the operating room. Venous, arterial and pulmonary artery catheterizations were done under local anaesthesia. No significant changes were noted in systolic blood pressure and rate pressure product. Heart rate was decreased after internal jugular puncture and for the remainder of the study. PaCO2 increased and PaO2 decreased from values obtained the day before operation. Cardiovascular stability during vascular catheterization was achieved by emphasizing a detailed preoperative explanation, maintenance of beta-blockade up to the time of operation, substantial sedative premedication, and the liberal use of local anaesthesia.