A sudden arterial blood pressure decrease is compensated by an increase in intracranial blood volume

2002 ◽  
Vol 249 (5) ◽  
pp. 538-541 ◽  
Author(s):  
Bernhard Rosengarten ◽  
Damian Rüskes ◽  
Irene Mendes ◽  
Erwin Stolz
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Blood Volume ◽  
Blood Pressure Decrease ◽  
Arterial Blood ◽  
Pressure Decrease

Supine exercise restores arterial blood pressure and skin blood flow despite dehydration and hyperthermia

1999 ◽  
Vol 277 (2) ◽  
pp. H576-H583 ◽  
Author(s):  
José González-Alonso ◽  
Ricardo Mora-Rodríguez ◽  
Edward F. Coyle
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Arterial Blood Pressure ◽  
Blood Volume ◽  
Plasma Catecholamines ◽  
Central Blood Volume ◽  
Vascular Conductance ◽  
Arterial Blood ◽  
Cutaneous Vascular Conductance

We determined whether the deleterious effects of dehydration and hyperthermia on cardiovascular function during upright exercise were attenuated by elevating central blood volume with supine exercise. Seven trained men [maximal oxygen consumption (V˙o 2 max) 4.7 ± 0.4 l/min (mean ± SE)] cycled for 30 min in the heat (35°C) in the upright and in the supine positions (V˙o 2 2.93 ± 0.27 l/min) while maintaining euhydration by fluid ingestion or while being dehydrated by 5% of body weight after 2 h of upright exercise. When subjects were euhydrated, esophageal temperature (Tes) was 37.8–38.0°C in both body postures. Dehydration caused equal hyperthermia during both upright and supine exercise (Tes = 38.7–38.8°C). During upright exercise, dehydration lowered stroke volume (SV), cardiac output, mean arterial pressure (MAP), and cutaneous vascular conductance and increased heart rate and plasma catecholamines [30 ± 6 ml, 3.0 ± 0.7 l/min, 6 ± 2 mmHg, 22 ± 8%, 14 ± 2 beats/min, and 50–96%, respectively; all P < 0.05]. In contrast, during supine exercise, dehydration did not cause significant alterations in MAP, cutaneous vascular conductance, or plasma catecholamines. Furthermore, supine versus upright exercise attenuated the increases in heart rate (7 ± 2 vs. 9 ± 1%) and the reductions in SV (13 ± 4 vs. 21 ± 3%) and cardiac output (8 ± 3 vs. 14 ± 3%) (all P< 0.05). These results suggest that the decline in cutaneous vascular conductance and the increase in plasma norepinephrine concentration, independent of hyperthermia, are associated with a reduction in central blood volume and a lower arterial blood pressure.

scholarly journals Effects of glucagon-like peptide-1(7-36) amide on neurohypophysial and cardiovascular functions under hypo- or normotensive hypovolaemia in the rat

2002 ◽  
Vol 172 (2) ◽  
pp. 303-310 ◽  
Author(s):  
E Bojanowska ◽  
B Stempniak
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Blood Volume ◽  
Mean Arterial Blood Pressure ◽  
Volume Depletion ◽  
Arterial Blood ◽  
The Mean ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Cardiovascular Functions

To date, glucagon-like peptide 1(7-36) amide (tGLP-1) has been found to affect the neurohypophysial and cardiovascular functions in normotensive and normovolaemic rats. The aim of the present study was to investigate possible effects of tGLP-1 on the mean arterial blood pressure and the release of vasopressin and oxytocin under conditions of blood volume depletion in the rat. In the first series of experiments, the animals were injected i.p. with either 0.15 M saline or 30% polyethylene glycol (PEG). PEG caused an 18% reduction of blood volume 1 h after injection. No significant changes in the mean arterial blood pressure were found in either normo- or hypovolaemic rats during the experiment. tGLP-1 injected i.c.v. at a dose of 1 microg/5 microl 1 h after the i.p. injection increased similarly the arterial blood pressure in normo- and hypovolaemic rats. The plasma vasopressin/oxytocin concentrations were markedly elevated in hypovolaemic animals and tGLP-1 further augmented the release of both hormones. In the second study, hypovolaemia was induced by double blood withdrawal. The haemorrhage resulted in a marked decrease of the mean arterial blood pressure and in the elevated plasma vasopressin/oxytocin concentrations. tGLP-1 injected immediately after the second blood withdrawal increased the arterial blood pressure. In parallel, tGLP-1 enhanced significantly vasopressin and oxytocin secretion when compared with haemorrhaged, saline-injected rats. The results of this study indicate that tGLP-1 may affect the arterial blood pressure and the secretion of neurohypophysial hormones under pathological conditions brought about by blood volume depletion.

scholarly journals Management of initial orthostatic hypotension: lower body muscle tensing attenuates the transient arterial blood pressure decrease upon standing from squatting

2007 ◽  
Vol 113 (10) ◽  
pp. 401-407 ◽  
Author(s):  
C. T. Paul Krediet ◽  
Ingeborg K. Go-Schön ◽  
Yu-Sok Kim ◽  
Mark Linzer ◽  
Johannes J. Van Lieshout ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Orthostatic Hypotension ◽  
Healthy Subjects ◽  
Lower Body ◽  
Blood Pressure Decrease ◽  
Body Muscle ◽  
Arterial Blood ◽  
Pressure Decrease ◽  
Standing Up ◽  
Initial Orthostatic Hypotension

IOH (initial orthostatic hypotension) comprises symptoms of cerebral hypoperfusion caused by an abnormally large transient MAP (mean arterial pressure) decrease 5–15 s after arising from a supine, sitting or squatting position. Few treatment options are available. In the present study, we set out to test the hypothesis that LBMT (lower body muscle tensing) attenuates IOH after rising from squatting and its symptoms in daily life. A total of 13 IOH patients (nine men; median age, 27 years) rose from squatting twice, once with LBMT and once without. In addition, seven healthy volunteers (five men; median age, 27 years) were studied in a cross-over study design. They stood up from the squatting position three times, once combined with LBMT. Blood pressure (Finometer) was measured continuously, and CO (cardiac output) by Modelflow and TPR (total peripheral resistance) were computed. MAP, CO and TPR were compared without and with LBMT. Using a questionnaire, the perceived effectiveness of LBMT in the patients' daily lives was evaluated. With LBMT, the minimal MAP after standing up was higher in both groups (19 mmHg in patients and 13 mmHg in healthy subjects). In healthy subjects, the underlying mechanism was a blunted TPR decrease (to 47% compared with 60%; P<0.05), whereas in the patients no clear CO or TPR pattern was discernible. During follow-up, eight out of ten patients using LBMT reported fewer IOH symptoms. In conclusion, LBMT is a new intervention to attenuate the transient blood pressure decrease after standing up from squatting, and IOH patients should be advised about the use of this manoeuvre.

Relation Between Arterial Blood Pressure and Blood Volume and Effect of Infused Albumin in Sick Preterm Infants

PEDIATRICS ◽  
1977 ◽  
Vol 60 (3) ◽  
pp. 282-289
Author(s):  
Peter A. Barr ◽  
Penrhyn E. Bailey ◽  
James Sumners ◽  
George Cassady
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Preterm Infants ◽  
Blood Volume ◽  
Hyaline Membrane Disease ◽  
Mean Blood Pressure ◽  
Albumin Infusion ◽  
Arterial Blood ◽  
Hyaline Membrane ◽  
Blood Pressures

The relation between directly measured arterial blood pressure and blood volume was studied in 61 sick preterm infants. Mean blood volume (derived from plasma volume [T1824 ten-minute albumin space] and hematocrit value) of 26 hypotensive infants (89.1 ± 17.26 ml/kg) was not significantly different from that of 35 normotensive, but otherwise comparable, infants (91.4 ± 14.57 ml/kg). There was no relation between arterial mean blood pressure and blood volume. Twenty-one infants with arterial mean blood pressure less than 30 mm Hg were given 1.0 g/kg of 10% salt-poor albumin. Significant increases in blood pressure occurred but were small in magnitude; more than one half of infants had arterial mean blood pressures persistently less than 30 mm Hg. Arterial/alveolar Po2 ratio decreased significantly with albumin infusion in six infants with hyaline membrane disease not receiving continuous distending-airway pressure, suggesting an association between infused albumin and impaired oxygen exchange.

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