Cerebral blood flow, blood volume, and brain tissue hematocrit during isovolemic hemodilution with hetastarch in rats

1992 ◽  
Vol 263 (1) ◽  
pp. H75-H82 ◽  
Author(s):  
M. M. Todd ◽  
J. B. Weeks ◽  
D. S. Warner
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Cell ◽  
Cell Volume ◽  
Brain Tissue ◽  
Blood Volume ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Isovolemic Hemodilution ◽  
Blood Cell And Plasma

The influence of isovolemic hemodilution with 6% hetastarch [hematocrits (Hct) ranging from 43 to 20%] on cerebral blood flow (CBF), cerebral red blood cell and plasma volumes, total cerebral blood volume (CBV), and cerebral Hct was examined in normothermic, normocarbic, halothane-anesthetized Sprague-Dawley rats. CBF was measured via the indicator-fractionation method ([3H]nicotine), red blood cell volume was measured using 99mTc-labeled red blood cells, while plasma volume was measured using [14C]dextran. Brain tissue was fixed in situ by microwave irradiation. All data plots (e.g., CBF vs. Hct) were fitted by linear regression methods. Hemodilution was associated with a progressive increase in forebrain CBF (from a fitted value of 78 ml.100 g-1.min-1 at Hct = 43%, to 171 ml.100 g-1.min-1 at 20%). Cerebral plasma volume also rose, while red blood cell volume decreased. Total CBV (i.e., the sum of red blood cell and plasma volumes) increased in parallel with CBF (from 2.51 ml/100 g at Hct = 43 to 4.94 ml/100 g at Hct = 20%). This increase is larger than can be explained by a simple increase in the diameter of arterial/arteriolar resistance vessels and may be due to either capillary recruitment or to an increase in the volume of postarteriolar structures. Calculated cerebral tissue hematocrit decreased. The magnitude of this decrease was larger than the reduction in arterial Hct; the ratio of cerebral to arterial Hct decreased from 0.780 at an arterial Hct equaling 43% to 0.458 at Hct equaling 20%.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Regulation of blood volume in lowlanders exposed to high altitude

2017 ◽  
Vol 123 (4) ◽  
pp. 957-966 ◽  
Author(s):  
Christoph Siebenmann ◽  
Paul Robach ◽  
Carsten Lundby
Keyword(s):  
Blood Cell ◽  
High Altitude ◽  
Cell Volume ◽  
Blood Volume ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Hemoglobin Concentration ◽  
Circulating Blood Volume ◽  
Oxyhemoglobin Saturation ◽  
Physiological Relevance

Humans ascending to high altitude (HA) experience a reduction in arterial oxyhemoglobin saturation and, as a result, arterial O2content ([Formula: see text]). As HA exposure extends, this reduction in [Formula: see text] is counteracted by an increase in arterial hemoglobin concentration. Initially, hemoconcentration is exclusively related to a reduction in plasma volume (PV), whereas after several weeks a progressive expansion in total red blood cell volume (RCV) contributes, although often to a modest extent. Since the decrease in PV is more rapid and usually more pronounced than the expansion in RCV, at least during the first weeks of exposure, a reduction in circulating blood volume is common at HA. Although the regulation of hematological responses to HA has been investigated for decades, it remains incompletely understood. This is not only related to the large number of mechanisms that could be involved and the complexity of their interplay but also to the difficulty of conducting comprehensive experiments in the often secluded HA environment. In this review, we present our understanding of the kinetics, the mechanisms and the physiological relevance of the HA-induced reduction in PV and expansion in RCV.

Blood flow and volume distribution during forced submergence in Pekin ducks (Anas platyrhynchos)

1988 ◽  
Vol 66 (7) ◽  
pp. 1589-1596 ◽  
Author(s):  
M. R. A. Heieis ◽  
David R. Jones
Keyword(s):  
Blood Flow ◽  
Blood Cell ◽  
Red Blood Cells ◽  
Cell Volume ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Area Measurement ◽  
Volume Distribution ◽  
Residual Blood ◽  
Time Required

Blood is the major oxygen store in ducks forced to dive, and underwater endurance depends on how much of this store can be used by oxygen-sensitive tissues such as the heart and brain. Arterial injection of macroaggregated albumin labelled with technetium-99 m, which is trapped and held by capillaries, showed that circulation in dives was restricted to the thoracic and head areas. However, tracing red blood cells labelled with technetium-99 m as they were injected during dives showed not only that the time required for the activity to reach equilibrium was 4–10 times longer than when labelled cells were injected into resting ducks but also that blood flow continued in the leg and visceral regions. Tracing red blood cells, labelled with technetium-99 m and mixed in the circulation before a dive, during the dive showed that labelled red blood cells were redistributed from the peripheral and visceral areas to the central cardiovascular area. Measurement of circulating red blood cell volume during and after diving showed that, on average, 75.24 ± 4.56% of the total red blood cell volume was circulated during forced submergence. Hence, in forced dives, red blood cell volume is positioned in such a manner that the heart and brain have access to the oxygen stored there, and the residual blood flow in the periphery ensures that most of the red blood cell volume is circulated.

scholarly journals Evaluation of cobalt as a performance enhancing drug (PED) in racehorses

2020 ◽  
Vol 16 (4) ◽  
pp. 243-252
Author(s):  
K.H. McKeever ◽  
K. Malinowski ◽  
C.K. Fenger ◽  
W.C. Duer ◽  
G.A. Maylin
Keyword(s):  
Adverse Effects ◽  
Blood Cell ◽  
Blood Volume ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Jugular Vein ◽  
Anaerobic Exercise ◽  
Science Center ◽  
Performance Enhancing ◽  
A Performance

Cobalt is a required trace element in animals, but administration in excess is considered dangerous and potentially performance enhancing in equine athletes. This study seeks to determine if cobalt may actually act as a performance enhancing drug (PED) by altering biochemical parameters related to red blood cell production as well as markers of aerobic and anaerobic exercise performance. In addition, for adequate regulation of naturally occurring substances, such as cobalt, its distribution among the population must be defined. In order to identify this distribution, plasma Cobalt was determined from 245 Standardbred horses with no cobalt supplementation from farms in New York and New Jersey, including horses at the Rutgers University Equine Science Center. Samples were analysed by Inductively Coupled Plasma Mass Spectrometry. Seven healthy, race fit Standardbreds (4 geldings, 3 mares, age: 5±3 years, ~500 kg) were used for the PED experiment. An incremental graded exercise test (GXT) to measure maximal aerobic capacity (V̇O2max) and markers of performance, measurement of plasma volume and blood volume as well as the measurement of lactate, erythropoietin (EPO), and various blood haematological factors were determined 7 days prior to cobalt administration. Each horse was administered a sterile solution of cobalt salts (50 mg of elemental Co as CoCl2 in 10 ml of saline, IV) at 9 AM on three consecutive days via the jugular vein. Blood samples were obtained from the contralateral jugular vein before and at 1, 2, 4 and 24 h after administration. Plasma and blood volume were measured one day after the last dose of cobalt, and a post administration GXT was performed the next day. Horses were observed for signs of adverse effects of the cobalt administration (agitation, sweating, increased respiration, etc.). Plasma cobalt concentration increased from a pre-administration mean of 1.6±0.6 to 369±28 μg/l following 3 doses of the cobalt solution (P<0.05). This Co concentration was unaccompanied by changes in aerobic or anaerobic performance, plasma EPO concentration, plasma volume, resting blood volume, total blood volume, or estimated red blood cell volume (P>0.05). There were no observed adverse effects.

Blood Volume Changes during Three-Week Residence at High Altitude

1970 ◽  
Vol 16 (1) ◽  
pp. 7-14 ◽  
Author(s):  
L G Myhre ◽  
D B Dill ◽  
F G Hall ◽  
D K Brown
Keyword(s):  
Carbon Monoxide ◽  
Blood Cell ◽  
High Altitude ◽  
Cell Volume ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Hemoglobin Concentration ◽  
Red Cell ◽  
Volume Changes ◽  
Cell Volumes

Abstract Circulating red blood cell volumes were determined by the carbon monoxide method, and plasma volumes were calculated in four men 20, 29, 71, and 75 years old, and two women 29 years of age before, during, and after exposure to an altitude of 3800 m. In the four youngest subjects there were early increases in hemoglobin concentration during the first days at the stated altitude attributed to decreases in plasma volume. At the same time, hemoglobin concentration decreased and plasma volume increased in the oldest subject. Red cell volumes were slow to change, and it was concluded that 3 weeks or more of exposure to this altitude are required to affect significantly the red cell volume in man.

Importance of Monitoring the Circulating Blood Volume in Patients with Cerebral Vasospasm after Subarachnoid Hemorrhage

Neurosurgery ◽  
1981 ◽  
Vol 9 (5) ◽  
pp. 514-520 ◽  
Author(s):  
Tadashi Kudo ◽  
Shigeharu Suzuki ◽  
Takashi Iwabuehi
Keyword(s):  
Blood Cell ◽  
Cell Volume ◽  
Blood Volume ◽  
Red Blood Cell ◽  
Cerebral Aneurysms ◽  
Neurological Deterioration ◽  
Red Cell ◽  
Dilution Technique ◽  
Circulating Blood Volume ◽  
Time Of Admission

Abstract We used the isotope dilution technique to monitor circulating blood volume (CBV) in three patients with ruptured cerebral aneurysms who developed pre- or postoperative ischemic symptoms that responded well to intravascular volume expansion therapy with blood transfusion and plasma expanders. In the first and second cases, predeterioration CBVs were obtained. Both of these patients showed hypovolemia and a decreased red blood cell volume at the time of neurological deterioration. A predeterioration CBV was not available for the third patient for comparison, but his red cell volume was also markedly decreased. Postrecovery CBVs were obtained in the second and third cases. Our data suggested that a depleted red blood cell volume was more responsible for neurological deterioration than was a lowered plasma volume. To prevent the occurrence of hypovolemia and anemia in aneurysm patients, we should monitor CBV not only at the time of neurological deterioration, but also at the time of admission and during the immediate postoperative period.

scholarly journals Erythropoiesis with endurance training: dynamics and mechanisms

2017 ◽  
Vol 312 (6) ◽  
pp. R894-R902 ◽  
Author(s):  
David Montero ◽  
Andreas Breenfeldt-Andersen ◽  
Laura Oberholzer ◽  
Thomas Haider ◽  
Jens P. Goetze ◽  
...  
Keyword(s):  
Blood Cell ◽  
Endurance Training ◽  
Cell Volume ◽  
Natriuretic Peptide ◽  
Plasma Volume ◽  
Red Blood Cell ◽  
Cycle Ergometry ◽  
Hematological Markers ◽  
Linear Relationships ◽  
Overnight Fasting

The purpose of the present study was to characterize the progression of red blood cell volume (RBCV) expansion and potential volumetric and endocrine regulators of erythropoiesis during endurance training (ET). Nine healthy, untrained volunteers (age = 27 ± 4 yr) underwent supervised ET consisting of 3–4 × 60 min cycle ergometry sessions per week for 8 wk. Plasma volume (PV), RBCV, and overnight fasting hematological markers were determined before and at weeks 2, 4, and 8 of ET. In addition, plasma erythropoietin (EPO), cortisol, copeptin, and proatrial natriuretic peptide concentrations were measured during a 3-h morning period at baseline and postexercise at weeks 1 and 8. PV increased from baseline (2,405 ± 335 ml) at weeks 2, 4, and 8 (+374 ± 194, +505 ± 156, and +341 ± 160 ml, respectively, P < 0.001). Increases in RBCV from baseline (1,737 ± 442 ml) were manifested at week 4 (+109 ± 114 ml, P = 0.030) and week 8 (+205 ± 109 ml, P = 0.001). Overnight fasting plasma EPO concentration increased from baseline (11.3 ± 4.8 mIU/ml) at week 2 (+2.5 ± 2.8 mIU·ml−1, P = 0.027) and returned to baseline concentration at weeks 4 and 8. Higher 3-h-postexercise EPO concentration was observed at week 1 (11.6 mIU/ml) compared with week 8 (8.4 ± 3.9 mIU/ml, P = 0.009) and baseline (9.0 ± 4.2 mIU/ml, P = 0.019). Linear relationships between EPO concentration and hematocrit (β = −56.2, P < 0.001) and cortisol (β = 0.037, P < 0.001) were detected throughout the ET intervention. In conclusion, ET leads to mild, transient increases in circulating EPO concentration, concurring with early PV expansion and lowered hematocrit, preceding gradual RBCV enhancement.

scholarly journals Laboratory and Genetic Biomarkers Associated with Cerebral Blood Flow Velocity in Hemoglobin SC Disease

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Rayra Pereira Santiago ◽  
Camilo Vieira ◽  
Corynne Stephanie Ahouefa Adanho ◽  
Sanzio Silva Santana ◽  
Caroline Conceição Guarda ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Cell ◽  
Flow Velocity ◽  
Red Blood Cell ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Distribution Width ◽  
Genetic Biomarkers ◽  
Hemoglobin Sc Disease

Reference values for cerebral blood flow velocity (CBFV) in hemoglobin SC disease (HbSC) have not been established. We aimed to investigate associations between laboratory and genetic biomarkers associated with CBFV in HbSC children. Sixty-eight HbSC children were included; CBFV was analyzed by transcranial Doppler, and the time-averaged maximum mean velocity (TAMMV) was estimated. Hematological, biochemical, immunological, and genetic analyses were performed. TAMMV was negatively correlated with red blood cell count (RBC) count, hemoglobin, hematocrit, and direct bilirubin (DB), yet positively correlated with monocytes and ferritin. We found that children with TAMMV ≥ 128 cm/s had decreased red blood cell distribution width (RDW) and nitric oxide metabolite (NOx) concentration. Children with TAMMV ≥ 143.50 cm/s had decreased hemoglobin and hematocrit, as well as increased ferritin levels. Decreased hemoglobin, hematocrit, RDW, and NOx and increased ferritin were detected in children with TAMMV ≥ 125.75 cm/s. The CAR haplotype was associated with higher TAMMV. In association analyses, RBC, hemoglobin, hematocrit, RDW, monocyte, DB, NOx, and ferritin, as well as the CAR haplotype, were found to be associated with higher TAMMV in HbSC children. Multivariate analysis suggested that high TAMMV was independently associated with hematocrit, RDW, and NOx. Additional studies are warranted to validate the establishment of a cutoff value of 125.75 cm/s associated with elevated TAMMV in HbSC children.

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