scholarly journals The Effect of Body Position and Forelimb Exercise on Cephalic Blood Flow

Stroke ◽  
1971 ◽  
Vol 2 (2) ◽  
pp. 168-192 ◽  
Author(s):  
WAKOU ANAZAWA ◽  
KOJI SHIGENO ◽  
JAMES F. TOOLE ◽  
RICHARD JANEWAY
Keyword(s):  
Blood Flow ◽  
Body Position ◽  
Cephalic Blood Flow

Estimation of pituitary secretion rate during the reproductive cycle of sheep

1990 ◽  
Vol 114 (2) ◽  
pp. 213-218
Author(s):  
K. S. Lindsay ◽  
I. R. Fleet ◽  
D. E. Walters ◽  
R. B. Heap
Keyword(s):  
Blood Flow ◽  
Reproductive Cycle ◽  
Hormone Secretion ◽  
Pituitary Hormone ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Pituitary Secretion ◽  
Conscious Sheep ◽  
Cephalic Blood Flow ◽  
Secretion Rates

SUMMARYA technique has been developed for the measurement of pituitary hormone secretion rates in conscious sheep. The technique involves the continuous and simultaneous sampling of blood from the carotid artery and jugular vein and the measurement of cephalic blood flow by an indicator dilution technique. Veno-arterial differences in hormone concentrations multiplied by cephalic blood flow gave average secretion rates which were measured after single or repeated large doses of luteinizing hormone releasing hormone (LHRH) and thyrotrophin-releasing hormone (TRH) at various times in the reproductive cycle.

Sympathetic modulation of blood flow and O2 uptake in rhythmically contracting human forearm muscles

1992 ◽  
Vol 263 (4) ◽  
pp. H1078-H1083 ◽  
Author(s):  
M. J. Joyner ◽  
L. A. Nauss ◽  
M. A. Warner ◽  
D. O. Warner
Keyword(s):  
Blood Flow ◽  
Body Position ◽  
Maximum Voluntary Contraction ◽  
Sympathetic Nerves ◽  
Work Load ◽  
Voluntary Contraction ◽  
Sympathetic Block ◽  
O2 Uptake ◽  
Fick Principle ◽  
Rhythmic Exercise

This study tested the effects of sympathetically mediated changes in blood flow to active muscles on muscle O2 uptake (VO2) in humans. Four minutes of graded (15-80% of maximum voluntary contraction, MVC) rhythmic handgrip exercise were performed. Forearm blood flow (FBF) (plethysmography) and deep vein O2 saturation were measured each minute. Forearm O2 uptake was calculated using the Fick principle. In protocol 1, exercise was performed while supine and again while upright to augment sympathetic outflow to the active muscles. Standing reduced FBF at rest from 3.6 to 2.2 ml.100 ml-1.min-1 (P < 0.05). During light exercise (15-40% MVC) FBF was unaffected by body position. Standing reduced FBF (P < 0.05) from 36.0 to 25.2 ml.100 ml-1.min-1 and forearm VO2 from 38.2 to 28.1 ml.kg-1.min-1 during the final work load. In protocol 2, exercise was performed while supine before and after local anesthetic block of the sympathetic nerves to the forearm. Sympathetic block increased FBF at rest from 3.1 to 8.9 ml.100 ml-1.min-1 (P < 0.05), and FBF was higher during all work loads At 70-80% of MVC sympathetic block increased FBF from 35.4 to 50.7 ml.100 ml-1.min-1 (P < 0.05), and forearm VO2 from 45.5 to 54.2 ml.kg-1.min-1 (P < 0.05). These results suggest that in humans sympathetic nerves modulate blood flow to active muscles during light and heavy rhythmic exercise and that this restraint of flow can limit O2 uptake in muscles performing heavy rhythmic exercise.

Abstract 114: Effect of Body Position on Intracranial Pressure and Carotid Blood Flow During Extracorporeal Cardiopulmonary Resuscitation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_4) ◽  
Author(s):  
Yaël Levy ◽  
Rocio Fernandez ◽  
Fanny Lidouren ◽  
Matthias Kohlhauer ◽  
Lionel Lamhaut ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Arrest ◽  
Intracranial Pressure ◽  
Cardiopulmonary Resuscitation ◽  
Body Position ◽  
Spontaneous Circulation ◽  
Systemic Hemodynamics ◽  
Body Tilt ◽  
Whole Body ◽  
Extracorporeal Cardiopulmonary Resuscitation

Introduction: Extracorporeal cardiopulmonary resuscitation (E-CPR) using extracorporeal membrane oxygenation (ECMO) is widely proposed for the treatment of refractory cardiac arrest. Hypothesis: Since cerebral autoregulation is altered in such conditions, body position may modify hemodynamics during ECPR. Our goal was to determine whether a whole body tilt-up challenge (TUC) could lower intracranial pressure (ICP) as previously shown with conventional CPR, without deteriorating cerebral blood flow (CBF). Methods: Pigs were anesthetized and instrumented for the continuous evaluation of CBF, ICP and systemic hemodynamics. After 15 min of untreated ventricular fibrillation they were treated with 30 min of E-CPR followed by sequential defibrillation shocks until resumption of spontaneous circulation (ROSC). ECMO was continued after ROSC to target a mean arterial pressure (MAP) >60 mmHg. Animals were maintained in the flat position (FP) throughout protocol, except during a 2 min TUC of the whole body (+30°) at baseline, during E-CPR and after-ROSC. Results: Four animals received the entire procedure and ROSC was obtained in 3/4. After cardiac arrest, E-CPR was delivered at 29±2 ml/kg/min to maintain a MAP of 57±8 mmHg in the FP. CBF was 28% of baseline and ICP remain stable (12±1 vs 13±1 mmHg during ECPR vs baseline, respectively). Under baseline pre-arrest conditions TUC resulted in a significant decrease in ICP (-63±7%) and CBF (-21±3%) versus the FP, with no significant effect on systemic hemodynamics. During E-CPR and after ROSC, TUC markedly reduced ICP but CBF remained unchanged vs the FP (Figure). Conclusion: During E-CPR whole body TUC reduced ICP without lowering CBF compared with E-CPR flat. Additional investigations with prolonged TUC and selective head and thorax elevation during E-CPR are warranted.

scholarly journals Supine, prone, right and left gravitational effects on human pulmonary circulation

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Björn Wieslander ◽  
Joao Génio Ramos ◽  
Malin Ax ◽  
Johan Petersson ◽  
Martin Ugander
Keyword(s):  
Blood Flow ◽  
Intensive Care ◽  
Blood Volume ◽  
Pulmonary Blood Flow ◽  
Body Position ◽  
Dependent Lung ◽  
Pulmonary Hemodynamics ◽  
Gravitational Effects ◽  
Volume Variation ◽  
Arterial Blood

Abstract Background Body position can be optimized for pulmonary ventilation/perfusion matching during surgery and intensive care. However, positional effects upon distribution of pulmonary blood flow and vascular distensibility measured as the pulmonary blood volume variation have not been quantitatively characterized. In order to explore the potential clinical utility of body position as a modulator of pulmonary hemodynamics, we aimed to characterize gravitational effects upon distribution of pulmonary blood flow, pulmonary vascular distension, and pulmonary vascular distensibility. Methods Healthy subjects (n = 10) underwent phase contrast cardiovascular magnetic resonance (CMR) pulmonary artery and vein flow measurements in the supine, prone, and right/left lateral decubitus positions. For each lung, blood volume variation was calculated by subtracting venous from arterial flow per time frame. Results Body position did not change cardiac output (p = 0.84). There was no difference in blood flow between the superior and inferior pulmonary veins in the supine (p = 0.92) or prone body positions (p = 0.43). Compared to supine, pulmonary blood flow increased to the dependent lung in the lateral positions (16–33%, p = 0.002 for both). Venous but not arterial cross-sectional vessel area increased in both lungs when dependent compared to when non-dependent in the lateral positions (22–27%, p ≤ 0.01 for both). In contrast, compared to supine, distensibility increased in the non-dependent lung in the lateral positions (68–113%, p = 0.002 for both). Conclusions CMR demonstrates that in the lateral position, there is a shift in blood flow distribution, and venous but not arterial blood volume, from the non-dependent to the dependent lung. The non-dependent lung has a sizable pulmonary vascular distensibility reserve, possibly related to left atrial pressure. These results support the physiological basis for positioning patients with unilateral pulmonary pathology with the “good lung down” in the context of intensive care. Future studies are warranted to evaluate the diagnostic potential of these physiological insights into pulmonary hemodynamics, particularly in the context of non-invasively characterizing pulmonary hypertension.

scholarly journals Sympathetic regulation of cephalic blood flow.

Stroke ◽  
1977 ◽  
Vol 8 (2) ◽  
pp. 197-201 ◽  
Author(s):  
M W Meyer ◽  
K A Smith ◽  
A C Klassen
Keyword(s):  
Blood Flow ◽  
Sympathetic Regulation ◽  
Cephalic Blood Flow

Evidence for a dorso-medial parietal system involved in mental transformations of the body

1996 ◽  
Vol 76 (3) ◽  
pp. 2042-2048 ◽  
Author(s):  
E. Bonda ◽  
S. Frey ◽  
M. Petrides
Keyword(s):  
Blood Flow ◽  
Parietal Cortex ◽  
Human Subjects ◽  
Body Position ◽  
The Body ◽  
Right Hand ◽  
Positron Emission ◽  
Superior Parietal Cortex ◽  
The Right ◽  
Mental Transformations

1. The neural systems underlying body-space mental representation were studied by measuring changes in regional cerebral blood flow (CBF) with positron emission tomography in human subjects. 2. The experimental paradigm involved identification of the left or the right hand of the experimenter presented in different orientations or the palm of the subject's right hand. The subjects were required to decide whether it was the left or the right hand that was presented. To perform this task, the subjects had to move mentally the position of their own arm to adopt that of the experimenter's arm. The control condition involved the same type of tactual stimulation without the requirement of mental transformations of the subject's body position. The distribution of CBF was measured by means of the water bolus H2(15)O methodology during the performance of these tasks. 3. Comparison of the distribution of CBF between the experimental and control tasks was carried out to reveal changes specific to the mental transformations of the subject's body. Significant blood flow increases were observed in the caudal superior parietal cortex, including the intraparietal sulcus, and the adjacent medial parietal cortex. These findings demonstrated that there is a dorsomedially directed parietal system underlying mental transformations of the body in interactive relation with external space.

Insufflation profile and body position influence portal venous blood flow during pneumoperitoneum

2003 ◽  
Vol 17 (12) ◽  
pp. 1951-1957 ◽  
Author(s):  
C. -G. Schmedt ◽  
O. Heupel ◽  
V. Riemer ◽  
C. N. Gutt
Keyword(s):  
Blood Flow ◽  
Body Position ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Portal Venous Blood Flow ◽  
Portal Venous Blood
Sign in / Sign up

Export Citation Format

Share Document