title: Nitric oxide-mediated vascular function in sepsis using passive leg movement as a novel assessment: a cross-sectional study.
abstract: Post-cuff occlusion flow-mediated dilation (FMD) is a proposed indicator of nitric oxide (NO) bioavailability and vascular function. FMD is reduced in patients with sepsis and may be a marker of end organ damage and mortality. However, FMD likely does not solely reflect NO-mediated vasodilation, is technically challenging, and often demonstrates poor reproducibility. In contrast, passive leg movement (PLM), a novel methodology to assess vascular function, yields a hyperemic response that is predominately NO-dependent, reproducible, and easily measured. This study evaluated PLM as an approach to assess NO-mediated vascular function in patients with sepsis. We hypothesized that PLM-induced hyperemia, quantified by the increase in leg blood flow (LBF), would be attenuated in sepsis. In a cross-sectional study, 17 subjects in severe sepsis or septic shock were compared with 16 matched healthy controls. Doppler ultrasound was used to assess brachial artery FMD and the hyperemic response to PLM in the femoral artery. FMD was attenuated in septic compared with control subjects (1.1 ± 1.7% vs. 6.8 ± 1.3%; values are means ± SD). In terms of PLM, baseline LBF (196 ± 33 ml/min vs. 328 ± 20 ml/min), peak change in LBF from baseline (133 ± 28 ml/min vs. 483 ± 86 ml/min), and the LBF area under the curve (16 ± 8.3 vs. 143 ± 33) were all significantly attenuated in septic subjects. Vascular function, as assessed by both FMD and PLM, is attenuated in septic subjects compared with controls. These data support the concept that NO bioavailability is attenuated in septic subjects, and PLM appears to be a novel and feasible approach to assess NO-mediated vascular function in sepsis.
authors: Department of Internal Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; ash.nelson@hsc.utah.edu.
authors: Ashley D
authors: AD
authors: Nelson
authors: Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah; and.
authors: Matthew J
authors: MJ
authors: Rossman
authors: Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware.
authors: Melissa A
authors: MA
authors: Witman
authors: Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah; and.
authors: Zachary
authors: Z
authors: Barrett-O'Keefe
authors: Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah; and.
authors: H Jonathan
authors: HJ
authors: Groot
authors: Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah;
authors: Ryan S
authors: RS
authors: Garten
authors: Department of Internal Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah; Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah; and.
authors: Russell S
authors: RS
authors: Richardson
mesh_terms: D001916:Brachial Artery / Q000378:metabolism / Q000503:physiopathology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005263:Femoral Artery / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D006940:Hyperemia / Q000378:metabolism / Q000503:physiopathology; D007866:Leg / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D018805:Sepsis / Q000378:metabolism* / Q000503:physiopathology*; D014664:Vasodilation / Q000502:physiology
chemical_list: D009569:Nitric Oxide
keywords: endothelial function; flow-mediated dilation; nitric oxide; passive leg movement; sepsis