title: Phenylephrine increases near-infrared spectroscopy determined muscle oxygenation in men.
abstract: Phenylephrine increases mean arterial pressure (MAP) by enhanced total peripheral resistance (TPR) but near-infrared spectroscopy (NIRS) determined muscle oxygenation (SmO2) increases. We addressed that apparent paradox during supine rest and head-up tilt (HUT). Variables were determined ± phenylephrine in males during supine rest (n = 17) and 40° HUT (n = 7). MAP, stroke volume (SV), heart rate (HR), and TPR were derived by Modelflow®and NIRS determined biceps SmO2and (tibial) bone oxygenation (StibialO2). For ten subjects, cardiac filling and the diameter of the inferior caval vein (ICV collapsibility index: ((ICVexpiration- ICVinspiration)/ICVexpiration) × 100) were assessed by ultrasound. Pancreatic polypeptide (PP) and atrial natriuretic peptide (proANP) in plasma were determined by immunoassay. Brachial artery blood flow was assessed by ultrasound and skin oxygenation (SskinO2) monitored by white light spectroscopy. Phenylephrine increased MAP by 34% and TPR (62%; P < 0.001) during supine rest. The ICV collapsibility index decreased (24%; P < 0.001) indicating augmented cardiac preload although volume of the left atrium and ventricle did not change. SV increased (18%; P < 0.001) as HR decreased (24%; P < 0.001). ProANP increased by 9% (P = 0.002) with unaffected PP. Brachial artery blood flow tended to decrease while SskinO2together with StibialO2decreased by 11% (P = 0.026) and 20% (P < 0.001), respectively. Conversely, phenylephrine increased SmO2(9%) and restored the HUT elicited decrease in SmO2(by 19%) along with SV (P = 0.02). Phenylephrine reduces skin and bone oxygenation and tends to reduce arm blood flow, suggesting that the increase in SmO2reflects veno-constriction with consequent centralization of the blood volume.
authors.affiliation: Department of Anesthesia, The Copenhagen Muscle Research Centre, University of Copenhagen, Rigshospitalet 2043, Blegdamsvej 9, DK-2100, Copenhagen Ø, Denmark. hs770@hotmail.com.
authors.forename: H
authors.identifier: http://orcid.org/0000-0003-0819-106X
authors.initials: H
authors.lastname: Sørensen
authors.affiliation: Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J H
authors.initials: JH
authors.lastname: Thomsen
authors.affiliation: Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: A S P
authors.initials: ASP
authors.lastname: Meyer
authors.affiliation: Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: D
authors.initials: D
authors.lastname: Terzic
authors.affiliation: Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Hilsted
authors.affiliation: Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Kjærgaard
authors.affiliation: Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J P
authors.initials: JP
authors.lastname: Goetze
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Brazil.
authors.forename: T C
authors.initials: TC
authors.lastname: Barbosa
authors.affiliation: Department of Anesthesia, The Copenhagen Muscle Research Centre, University of Copenhagen, Rigshospitalet 2043, Blegdamsvej 9, DK-2100, Copenhagen Ø, Denmark.
authors.forename: N H
authors.initials: NH
authors.lastname: Secher
mesh_terms: D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood; D001783:Blood Flow Velocity; D001810:Blood Volume; D001916:Brachial Artery; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007118:Immunoassay; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D010191:Pancreatic Polypeptide / Q000097:blood; D056888:Patient Positioning; D010656:Phenylephrine / Q000494:pharmacology*; D012867:Skin / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D016683:Supine Position; D013977:Tibia / Q000378:metabolism*; D055815:Young Adult
chemical_list: D010656:Phenylephrine; D010191:Pancreatic Polypeptide; D009320:Atrial Natriuretic Factor; D010100:Oxygen
keywords: Atrial natriuretic peptide; Muscle oxygenation; Near infrared spectroscopy; Pancreatic polypeptide; Phenylephrine; Skin oxygenation; Tibial bone oxygenation