title: Vasopressors induce passive pulmonary hypertension by blood redistribution from systemic to pulmonary circulation.
abstract: Vasopressors are widely used in resuscitation, ventricular failure, and sepsis, and often induce pulmonary hypertension with undefined mechanisms. We hypothesize that vasopressor-induced pulmonary hypertension is caused by increased pulmonary blood volume and tested this hypothesis in dogs under general anesthesia. In normal hearts (model 1), phenylephrine (2.5 μg/kg/min) transiently increased right but decreased left cardiac output, associated with increased pulmonary blood volume (63% ± 11.8, P = 0.007) and pressures in the left atrium, pulmonary capillary, and pulmonary artery. However, the trans-pulmonary gradient and pulmonary vascular resistance remained stable. These changes were absent after decreasing blood volume or during right cardiac dysfunction to reduce pulmonary blood volume (model 2). During double-ventricle bypass (model 3), phenylephrine (1, 2.5 and 10 μg/kg/min) only slightly induced pulmonary vasoconstriction. Vasopressin (1U and 2U) dose-dependently increased pulmonary artery pressure (52 ± 8.4 and 71 ± 10.3%), but did not cause pulmonary vasoconstriction in normally beating hearts (model 1). Pulmonary artery and left atrial pressures increased during left ventricle dysfunction (model 4), and further increased after phenylephrine injection by 31 ± 5.6 and 43 ± 7.5%, respectively. In conclusion, vasopressors increased blood volume in the lung with minimal pulmonary vasoconstriction. Thus, this pulmonary hypertension is similar to the hemodynamic pattern observed in left heart diseases and is passive, due to redistribution of blood from systemic to pulmonary circulation. Understanding the underlying mechanisms may improve clinical management of patients who are taking vasopressors, especially those with coexisting heart disease.
authors.affiliation: Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Chunling
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Qian
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Shuhua
authors.initials: S
authors.lastname: Luo
authors.affiliation: Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Disorders, Department of Medicine, University of Louisville, Louisville, KY, USA.
authors.forename: Jerry
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Yajiao
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: An
authors.affiliation: Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China.
authors.forename: Nanfu
authors.initials: N
authors.lastname: Luo
authors.affiliation: Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China. dulei@scu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Du
mesh_terms: D000818:Animals; D004285:Dogs; D006439:Hemodynamics / Q000502:physiology*; D006976:Hypertension, Pulmonary / Q000139:chemically induced*; D011652:Pulmonary Circulation / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000633:toxicity*
chemical_list: D014662:Vasoconstrictor Agents
keywords: Blood redistribution; Hemodynamics; Pulmonary circulation; Pulmonary hypertension, passive; Systemic circulation; Vasopressor agents