title: Reflex and mechanical circulatory effects of graded Valsalva maneuvers in normal man.
abstract: In 17 normal subjects we studied the changes evoked by five levels of expiratory pressure (EP) ranging from 2.5 to 30 mmHg in a number of circulatory variables during the last 10 s of a 30-s Valsalva maneuver. Variables studied included mean arterial (MAP) and pulse (PP) pressures; right atrial (RAP) and peripheral vein (PVP) pressures; cardiac output (CO); total peripheral resistance (TPR) and heart rate (HR). EP-circulatory response curves were obtained in each subject a) before autonomic block; b) after cardiac effector block (atropine + propranolol); c) after "total" autonomic block (atropine + propranolol; guanethidine + phentolamine). Mechanical effects were determined from results during "total" autonomic block. They included EP-related rises in RAP and PVP each to about 0.7 mmHg/mmHg applied EP, and falls in CO, MAP, and PP to levels of approximately 50%, 70%, and 80% of resting respectively at EP 30 mmHg, but no changes in TPR and HR. Reflex effects included EP-related rises in HR and in TPR and in MAP, to levels of 160%, 160%, and 115% of resting respectively at EP 30 mmHg. The afferent input profile is probably complex, and the role of the different receptor groups may vary at the different levels of EP.
mesh_terms: D016275:Atrial Function; D001285:Atropine / Q000494:pharmacology; D001340:Autonomic Nerve Block; D001794:Blood Pressure; D006328:Cardiac Catheterization; D002302:Cardiac Output; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D006339:Heart Rate; D006801:Humans; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D014636:Valsalva Maneuver; D014655:Vascular Resistance
chemical_list: D001285:Atropine; D011433:Propranolol; D010646:Phentolamine; D006145:Guanethidine