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Results for “BLOOD CIRCULATION”

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At least 55 records · Page 3Linked to original sources
PubMed1997

[Problems of laparoscopy using captoperitoneum: controlled ventilation, circulation, blood gas and body temperature].

More and more veterinarians are going to perform laparoscopic diagnosis and surgery those days. But the technique using capnoperitoneum implicates several alterations of different physiological parameters, which, without proper monitoring, are often realized to late. Pathophysiology under CO2 insufflated abdomen as well as counter measures to keep or reestablish physiological situations are described. Within experimental studies, 27 pigs received partial colon resection using the laparoscopic technique, another six after laparotomy. They were compared concerning controlled ventilation, cardiovascular and blood gas parameters as well as the body temperature. Monitoring of the end-exspiratory CO2-gas tension as well as controlled ventilation seems to be essential. Blood gas analyses are proposed additionally. Under the described laparoscopic conditions blood circulation and body temperature seem to be influenced positively.

Abdomen↗
PubMedDate not supplied

[Circulating blood volume meter].

The article describes the functional diagram, calibration principle and operation of a new instrument, ur1-7. This device measures the volume of blood circulating in the organism by the radioisotope dilution method. The measurement range is from 1 to 9.9 1, with error not exceeding +/- 5%.

Blood Volume Determination↗
PubMed1991

Influence of probe motion on laser probe temperature in circulating blood.

The purpose of this study was to evaluate the effect of probe motion on laser probe temperature in various blood flow conditions. Laser probe temperatures were measured in an in vitro blood circulation model consisting of 3.2 nm-diameter plastic tubes. A 2.0 mm-diameter metal probe attached to a 300 microns optical quartz fiber was coupled to an argon laser. Continuous wave 4 watts and 8 watts of laser power were delivered to the fiber tip corresponding to a 6.7 +/- 0.5 and 13.2 +/- 0.7 watts power setting at the laser generator. The laser probe was either moved with constant velocity or kept stationary. A thermocouple inserted in the lateral portion of the probe was used to record probe temperatures. Probe temperature changes were found with the variation of laser power, probe velocity, blood flow, and duration of laser exposure. Probe motion significantly reduced probe temperatures. After 10 seconds of 4 watts laser power the probe temperature in stagnant blood decreased from 303 +/- 18 degrees C to 113 +/- 17 degrees C (63%) by moving the probe with a velocity of 5 cm/sec. Blood flow rates of 170 ml/min further decreased the probe temperature from 113 +/- 17 degrees C to 50 +/- 8 degrees C (56%). At 8 watts of laser power a probe temperature reduction from 591 +/- 25 degrees C to 534 +/- 36 degrees C (10%) due to 5 cm/sec probe velocity was noted. Probe temperatures were reduced to 130 +/- 30 degrees C (78%) under the combined influence of 5 cm/sec probe velocity and 170 ml/min blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed2006

Recombinant human serum albumin dimer has high blood circulation activity and low vascular permeability in comparison with native human serum albumin.

PURPOSE: Human serum albumin (HSA) is used clinically as an important plasma expander. Albumin infusion is not recommended for critically ill patients with hypovolemia, burns, or hypoalbuminemia because of the increased leakage of albumin into the extravascular spaces, thereby worsening edema. In the present study, we attempted to overcome this problem by producing a recombinant HSA (rHSA) dimer with decreased vascular permeability and an increased half-life. METHODS: Two molecules of rHSA were genetically fused to produce a recombinant albumin dimer molecule. The pharmacokinetics and biodistribution of the recombinant proteins were evaluated in normal rats and carrageenin-induced paw edema mouse model. RESULTS: The conformational properties of this rHSA dimer were similar to those for the native HSA (the HSA monomer), as evidenced by the Western blot and spectroscopic studies. The biological half-life and area under the plasma concentration-time curve of the rHSA dimer were approximately 1.5 times greater than those of the monomer. Dimerization has also caused a significant decrease in the total body clearance and distribution volume at the steady state of the native HSA. rHSA dimer accumulated to a lesser extent in the liver, skin, muscle, and fat, as compared with the native HSA. Up to 96 h, the vascular permeability of the rHSA dimer was less than that of the native HSA in paw edema mouse models. A prolonged plasma half-life of the rHSA dimer was also observed in the edema model rats. CONCLUSIONS: rHSA dimer has a high retention rate in circulating blood and a lower vascular permeability than that of the native HSA.

Animals↗
PubMed1990

[The estimation of blood circulation parameters using imaging techniques--comparison with measurements made using the Swan-Ganz catheter].

Circulation can be evaluated by means of measuring parameters in X-ray-thorax and ultrasonography. Changes in haemodynamics can be estimated by measured changes in width of vena azygos. Additional sonography of systemic veins of thoracic inlet (V. jugularis interna, V. cava inferior) improves multiple correlation to circulating blood volume up to r = 0.81. Supine or erect position and type of ventilation are influencing factors. Diaphragm motility was measured by means of ultrasonography: patients with assisted ventilation showed significantly decreased motility compared to patients with spontaneous breathing.

Adult↗
PubMed2006

V1a vasopressin receptors maintain normal blood pressure by regulating circulating blood volume and baroreflex sensitivity.

Arginine-vasopressin (AVP) is a hormone that is essential for both osmotic and cardiovascular homeostasis, and exerts important physiological regulation through three distinct receptors, V1a, V1b, and V2. Although AVP is used clinically as a potent vasoconstrictor (V1a receptor-mediated) in patients with circulatory shock, the physiological role of vasopressin V1a receptors in blood pressure (BP) homeostasis is ill-defined. In this study, we investigated the functional roles of the V1a receptor in cardiovascular homeostasis using gene targeting. The basal BP of conscious mutant mice lacking the V1a receptor gene (V1a-/-) was significantly (P < 0.001) lower compared to the wild-type mice (V1a+/+) without a notable change in heart rate. There was no significant alteration in cardiac functions as assessed by echocardiogram in the mutant mice. AVP-induced vasopressor responses were abolished in the mutant mice; rather, AVP caused a decrease in BP, which occurred in part through V2 receptor-mediated release of nitric oxide from the vascular endothelium. Arterial baroreceptor reflexes were markedly impaired in mutant mice, consistent with a loss of V1a receptors in the central area of baroreflex control. Notably, mutant mice showed a significant 9% reduction in circulating blood volume. Furthermore, mutant mice had normal plasma AVP levels and a normal AVP secretory response, but had significantly lower adrenocortical responsiveness to adrenocorticotropic hormone. Taken together, these results indicate that the V1a receptor plays an important role in normal resting arterial BP regulation mainly by its regulation of circulating blood volume and baroreflex sensitivity.

Adrenal Cortex↗