title: A square-pulse flow method for measuring characteristics of the arterial bed.
abstract: A device was designed to provide a "square" pulse of blood flow into the arterial system. Pulses were injected into the carotid artery of the rabbit during transient cardiac arrest. Analysis of pressure response curves generated by the flow provides information as to the state of the arterial tree. With certain assumptions it is possible to estimate from these curves lumped values of peripheral resistance, critical closing pressure, and arterial compliance. In a series of 12 rabbits the mean value of peripheral resistance was found to be 0.21 +/- 0.7 mmHg-ml-1-min and critical closing pressure was estimated to be 23.6 +/- 3.8 mmHg. This method gives two possible values for arterial compliance 0.036 +/- 0.010 and 0.055 +/- 0.010 ml-mm-1 based, respectively, on the rise and decay curves of the pressure response. The theory and limitations of the method are discussed. The use of the method is illustrated in following the response to increased PCO2 and hemorrhage.
mesh_terms: D000818:Animals; D001158:Arteries / Q000502:physiology*; D001794:Blood Pressure; D003187:Compliance; D004594:Electrophysiology; D007263:Infusions, Parenteral / Q000295:instrumentation / Q000379:methods; D008954:Models, Biological; D011817:Rabbits; D012039:Regional Blood Flow; D012119:Respiration; D012965:Sodium Chloride; D014655:Vascular Resistance
chemical_list: D012965:Sodium Chloride