The central blood volume as measured by thoracic electrical impedance and plasma proANP is not compromised by donation of 900 mL of blood in men

2020 ◽  
Vol 30 (6) ◽  
pp. 450-455
Author(s):  
Mikkel Gybel‐Brask ◽  
Nikolai Baastrup Nordsborg ◽  
Jens P. Goetze ◽  
Pär I. Johansson ◽  
Niels H. Secher ◽  
...  
Keyword(s):  
Blood Volume ◽  
Electrical Impedance ◽  
Central Blood Volume ◽  
Thoracic Electrical Impedance

Restricted postexercise pulmonary diffusion capacity and central blood volume depletion

1997 ◽  
Vol 83 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Birgitte Hanel ◽  
Inge Teunissen ◽  
Alan Rabøl ◽  
Jørgen Warberg ◽  
Niels H. Secher
Keyword(s):  
Blood Volume ◽  
Electrical Impedance ◽  
Control Group ◽  
Central Blood Volume ◽  
Volume Depletion ◽  
Diffusion Capacity ◽  
Pulmonary Diffusion ◽  
Before And After ◽  
Pulmonary Diffusion Capacity

Hanel, Birgitte, Inge Teunissen, Alan Rabøl, Jørgen Warberg, and Niels H. Secher. Restricted postexercise pulmonary diffusion capacity and central blood volume depletion. J. Appl. Physiol. 83(1): 11–17, 1997.—Pulmonary diffusion capacity for carbon monoxide (Dl CO), regional electrical impedance (Z0), and the distribution of technetium-99m-labeled erythrocytes together with concentration of plasma atrial natriuretic peptide (ANP) were determined before and after a 6-min “all-out” row in nine oarsmen and in six control subjects. Two and one-half hours after exercise in the upright seated position, Dl CO was reduced by 6 (−2 to 21; median and range) %, the thoracic-to-thigh electrical impedance ratio (Z0 thorax/Z0 thigh) rose by 14 (−1 to 29) %, paralleled by a 7 (−3 to 11) % decrease and a 3 (−5 to 12) % increase in the thoracic and thigh blood volume, respectively. These responses were associated with a decrease in the plasma ANP concentration from 15 (13–31) to 12 (9–27) pmol/l ( P < 0.05). Similarly, in the supine position, Z0 thorax/Z0 thighincreased by 10 (−5 to 28) % when Dl CO was reduced 12 (6–26) % ( P < 0.05), whereas Dl COremained stable in the control group. The increase in Z0 thorax/Z0 thighand the corresponding redistribution of the blood volume in both body positions show that approximately one-half of the postexercise reduction of Dl CO is explained by a decrease in the pulmonary blood volume. The role of a reduced postexercise central blood volume is underscored by the lower plasma ANP, which aids in upregulating the blood volume after exercise in athletes.

Resonance in a mathematical model of baroreflex control: arterial blood pressure waves accompanying postural stress

2005 ◽  
Vol 288 (6) ◽  
pp. R1637-R1648 ◽  
Author(s):  
Peter E. Hammer ◽  
J. Philip Saul
Keyword(s):  
Blood Pressure ◽  
Mathematical Model ◽  
Blood Volume ◽  
Low Frequency ◽  
Pressure Waves ◽  
Central Blood Volume ◽  
Arterial Baroreflex ◽  
Arterial Blood ◽  
Gain Margin ◽  
The Stability

A mathematical model of the arterial baroreflex was developed and used to assess the stability of the reflex and its potential role in producing the low-frequency arterial blood pressure oscillations called Mayer waves that are commonly seen in humans and animals in response to decreased central blood volume. The model consists of an arrangement of discrete-time filters derived from published physiological studies, which is reduced to a numerical expression for the baroreflex open-loop frequency response. Model stability was assessed for two states: normal and decreased central blood volume. The state of decreased central blood volume was simulated by decreasing baroreflex parasympathetic heart rate gain and by increasing baroreflex sympathetic vaso/venomotor gains as occurs with the unloading of cardiopulmonary baroreceptors. For the normal state, the feedback system was stable by the Nyquist criterion (gain margin = 0.6), but in the hypovolemic state, the gain margin was small (0.07), and the closed-loop frequency response exhibited a sharp peak (gain of 11) at 0.07 Hz, the same frequency as that observed for arterial pressure fluctuations in a group of healthy standing subjects. These findings support the theory that stresses affecting central blood volume, including upright posture, can reduce the stability of the normally stable arterial baroreflex feedback, leading to resonance and low-frequency blood pressure waves.

scholarly journals Components of the "Central" Blood Volume in the Dog

1960 ◽  
Vol 8 (1) ◽  
pp. 93-99 ◽  
Author(s):  
ROBERT J. MARSHALL ◽  
YANG WANG ◽  
JOHN T. SHEPHERD
Keyword(s):  
Blood Volume ◽  
Central Blood Volume

Contribution of abdomen and legs to central blood volume expansion in humans during immersion

1997 ◽  
Vol 83 (3) ◽  
pp. 695-699 ◽  
Author(s):  
Lars Bo Johansen ◽  
Thomas Ulrik Skram Jensen ◽  
Bettina Pump ◽  
Peter Norsk
Keyword(s):  
Blood Volume ◽  
Volume Expansion ◽  
Protein Concentration ◽  
Water Immersion ◽  
Venous Pressure ◽  
Cuff Inflation ◽  
Central Blood Volume ◽  
Central Venous ◽  
Plasma Protein Concentration ◽  
Blood Volume Expansion

Johansen, Lars Bo, Thomas Ulrik Skram Jensen, Bettina Pump, and Peter Norsk. Contribution of abdomen and legs to central blood volume expansion in humans during immersion. J. Appl. Physiol. 83(3): 695–699, 1997.—The hypothesis was tested that the abdominal area constitutes an important reservoir for central blood volume expansion (CBVE) during water immersion in humans. Six men underwent 1) water immersion for 30 min (WI), 2) water immersion for 30 min with thigh cuff inflation (250 mmHg) during initial 15 min to exclude legs from contributing to CBVE (WI+Occl), and 3) a seated nonimmersed control with 15 min of thigh cuff inflation (Occl). Plasma protein concentration and hematocrit decreased from 68 ± 1 to 64 ± 1 g/l and from 46.7 ± 0.3 to 45.5 ± 0.4% ( P < 0.05), respectively, during WI but were unchanged during WI+Occl. Left atrial diameter increased from 27 ± 2 to 36 ± 1 mm ( P < 0.05) during WI and increased similarly during WI+Occl from 27 ± 2 to 35 ± 1 mm ( P < 0.05). Central venous pressure increased from −3.7 ± 1.0 to 10.4 ± 0.8 mmHg during WI ( P < 0.05) but only increased to 7.0 ± 0.8 mmHg during WI+Occl ( P < 0.05). In conclusion, the dilution of blood induced by WI to the neck is caused by fluid from the legs, whereas the CBVE is caused mainly by blood from the abdomen.

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