01 December 2005
Alternations of static cerebral and systemic circulation in normal humans during14-day head-down bed rest.
Kaname Hirayanagi, Satoshi Iwase, Atsunori Kamiya, Yoriko Watanabe, Tomoki Shiozawa, Nobuhisa Yamaguchi, Kazuyoshi Yajima, Tadaaki ManoMed Sci Monit 2005; 11(12): CR570-575 :: ID: 438853
Abstract
Background: There have so far been few reports on the static regulationsof cerebral and systemic circulation during prolonged head-down bed rest (HDBR). Our aim was to investigatethe time course changes in static cerebral and systemic circulation during 14 days of 6° degrees HDBR.Material/Methods: Sixteen subjects participated in the HDBR study. The systolic, mean, and diastoliccerebral blood flow velocities (CBFVs) of the middle cerebral artery were measured using a transcranialDoppler technique. Cerebrovascular bed resistance indices, i.e., resistance index (RI), pulsatility index(PI), and estimated regional cerebrovascular resistance (CVR[sub]est[/sub])) were calculated. The systemic cardiovascularfunctions, i.e, heart rate (HR), mean arterial pressure (MAP), left ventricular ejection time (LVET),stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were measured or calculated.Results: All CBFVs consistently showed significant decreases from the 2[sup]nd[/sup] day to the last day of theHDBR. The RI and PI showed a rising tendency throughout the HDBR. The CVR[sub]est[/sub] showed significantly higherlevels in the later half of the HDBR. The HR and MAP did not change during the HDBR. Conclusions: Theadaptive process of cerebral circulation triggered by HDBR begins very early and leads to a new equilibriumwithin few days after the onset of HDBR. The alteration of static cerebral circulation with prolongedHDBR, i.e., lowered CBFVs and somewhat higher cerebrovascular bed resistance implies a reduction in thecerebral circulation, but it does not necessarily imply the impaired regulation of cerebral circulation.
Keywords: Blood Flow Velocity, Bed Rest, Cardiovascular Physiological Phenomena, Cerebrovascular Circulation, Head-Down Tilt - physiology, Hemodynamics
Editorial
01 May 2024 : Editorial
Editorial: First Regulatory Approval for Adoptive Cell Therapy with Autologous Tumor-Infiltrating Lymphocytes (TILs) – Lifileucel (Amtagvi)DOI: 10.12659/MSM.944927
Med Sci Monit 2024; 30:e944927
In Press
12 Mar 2024 : Clinical Research
Comparing Neuromuscular Blockade Measurement Between Upper Arm (TOF Cuff®) and Eyelid (TOF Scan®) Using Miv...Med Sci Monit In Press; DOI: 10.12659/MSM.943630
11 Mar 2024 : Clinical Research
Enhancement of Frozen-Thawed Human Sperm Quality with Zinc as a Cryoprotective AdditiveMed Sci Monit In Press; DOI: 10.12659/MSM.942946
12 Mar 2024 : Database Analysis
Risk Factors of Age-Related Macular Degeneration in a Population-Based Study: Results from SHIP-TREND-1 (St...Med Sci Monit In Press; DOI: 10.12659/MSM.943140
12 Mar 2024 : Clinical Research
Preoperative Blood Transfusion Requirements for Hemorrhoidal Severe Anemia: A Retrospective Study of 128 Pa...Med Sci Monit In Press; DOI: 10.12659/MSM.943126
Most Viewed Current Articles
17 Jan 2024 : Review article
Vaccination Guidelines for Pregnant Women: Addressing COVID-19 and the Omicron VariantDOI :10.12659/MSM.942799
Med Sci Monit 2024; 30:e942799
14 Dec 2022 : Clinical Research
Prevalence and Variability of Allergen-Specific Immunoglobulin E in Patients with Elevated Tryptase LevelsDOI :10.12659/MSM.937990
Med Sci Monit 2022; 28:e937990
16 May 2023 : Clinical Research
Electrophysiological Testing for an Auditory Processing Disorder and Reading Performance in 54 School Stude...DOI :10.12659/MSM.940387
Med Sci Monit 2023; 29:e940387
01 Jan 2022 : Editorial
Editorial: Current Status of Oral Antiviral Drug Treatments for SARS-CoV-2 Infection in Non-Hospitalized Pa...DOI :10.12659/MSM.935952
Med Sci Monit 2022; 28:e935952