title: Wave reflections in the pulmonary arteries analysed with the reservoir-wave model.
abstract: Conventional haemodynamic analysis of pressure and flow in the pulmonary circulation yields incident and reflected waves throughout the cardiac cycle, even during diastole. The reservoir-wave model provides an alternative haemodynamic analysis consistent with minimal wave activity during diastole. Pressure and flow in the main pulmonary artery were measured in anaesthetized dogs and the effects of hypoxia and nitric oxide, volume loading and positive end-expiratory pressure were observed. The reservoir-wave model was used to determine the reservoir contribution to pressure and flow and once subtracted, resulted in 'excess' quantities, which were treated as wave-related. Wave intensity analysis quantified the contributions of waves originating upstream (forward-going waves) and downstream (backward-going waves). In the pulmonary artery, negative reflections of incident waves created by the right ventricle were observed. Overall, the distance from the pulmonary artery valve to this reflection site was calculated to be 5.7 ± 0.2 cm. During 100% O2 ventilation, the strength of these reflections increased 10% with volume loading and decreased 4% with 10 cmH2O positive end-expiratory pressure. In the pulmonary arterial circulation, negative reflections arise from the junction of lobar arteries from the left and right pulmonary arteries. This mechanism serves to reduce peak systolic pressure, while increasing blood flow.
authors.affiliation: Libin Cardiovascular Institute of Alberta james.bouwmeester@yale.edu.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Bouwmeester
authors.affiliation: Libin Cardiovascular Institute of Alberta Departments of Cardiac Sciences Medicine.
authors.forename: Israel
authors.initials: I
authors.lastname: Belenkie
authors.affiliation: Civil Engineering.
authors.forename: Nigel G
authors.initials: NG
authors.lastname: Shrive
authors.affiliation: Libin Cardiovascular Institute of Alberta Departments of Cardiac Sciences Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: John V
authors.initials: JV
authors.lastname: Tyberg
mesh_terms: D000818:Animals; D062186:Arterial Pressure; D004285:Dogs; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D008954:Models, Biological; D009200:Myocardial Contraction; D009569:Nitric Oxide / Q000502:physiology; D010100:Oxygen / Q000502:physiology; D011651:Pulmonary Artery / Q000502:physiology*; D011652:Pulmonary Circulation
chemical_list: D009569:Nitric Oxide; D010100:Oxygen
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