We deliberate a examine to analysis the relations amongst blood stress (BP), viscosity, and temperature in wholesome topics and amongst BP, viscosity, and glucose in diabetics. With easy random sampling technique, 53 wholesome and 29 diabetes mellitus (DM) kind II topics had been chosen. Parameters had been decided with capillary viscometer and glucometer at 22°C, 36.5°C, and 39.5°C in wholesome topics, and at 22°C on diabetic sufferers throughout OGTT with 75 g of glucose. Statistical evaluations of the information had been made with regression evaluation, Pupil t check, Spearman's correlation, and evaluation of variance. When temperature decreased from 36.5°C to 22°C, blood viscosity elevated 26.13%. This improve resulted in a 20.72% lower in blood stream fee. In line with the Hagen-Poiseuille equation, the required BP improve for compensation of the ensuing tissue ischemia was 20.72%. Additionally, a 34.73% lower in erythrocyte deformability and 18.71% improve in plasma viscosity had been seen. When temperature elevated from 36.5° to 39.5°C, blood viscosity decreased 10.38%. This prompted 11.15% lower in blood stream fee, and 11.15% lower in BP, in response to the equation. Erythrocyte deformability improve of 9.92% and plasma viscosity lower of 4.99% arose from the temperature rise. There's a correlation between whole information for temperatures and viscosities (r = −0.84, P < .001). When the imply worth of blood glucose elevated from 100 to 400 mg/dL, viscosity elevated 25% (r = 0.59, P = .002). On this state, blood stream fee lower was 20% and BP improve for physiological compensation was 25%. Consequently, temperature, glucose and viscosity ranges of blood are vital elements for BP. Am J Hypertens 2001;14:433–438 © 2001 American Journal of Hypertension, Ltd.
The intention of our examine is to analysis the relationships amongst temperature, glucose focus, and viscosity of blood and plasma, and to calculate their results on blood stress (BP) in response to Hagen-Poiseuille's hydrodynamics equation.
If the human circulatory system is taken into account as a closed system, hemodynamic equilibrium might be decided in response to Poiseuille's equation by way of the stress, viscosity, stream fee, velocity of blood, and vessel diameter. Viscosity might be outlined because the resistance of fluids towards stream. The resistance for blood circulation consists of friction between the blood parts and between the vessel lumen and blood. To make a fluid stream, the appliance of vitality is required. Due to this fact, the vitality of the circulatory system is spent in correlation with the viscosity stage of blood. Power types of the circulatory system are BP and blood stream velocity. The speed (v) and stress of blood stream might be decided with Poiseuille's equation as v = 1/4ηL (F1 − F2) (a2 − r2), and likewise BP fee (Q) might be expressed from the above equation as Q = πa4/Eight ηL (F1 − F2), the place η is the viscosity of the fluid, F1 and F2 are the preliminary and the ultimate cross sectional pressures of blood, L is the size, a is the radius of vessel, and r is the space from the middle of the vessel for a flowing particle.1,2 Thus, to maintain the equilibrium of the equation fixed within the circulatory system, BP will improve when viscosity will increase.
It has been proven that between 25.32% and 60.16% values of hematocrit, each 11% improve in hematocrit will increase blood viscosity by 20%. On this state, in response to Poiseuille's equation, blood stream fee decreases by 16.67%, which can result in tissue ischemia. To maintain the circulatory system in equilibrium (that's, protecting the stream fee ample and stopping tissue ischemia), a 20% improve in BP or 4.66% vasodilation is required.3 Nonetheless, the human circulatory system isn't a precise closed system, as a result of blood viscosity might be altered with the absorption of meals or medicine.4–8 Moreover, the consequences of dietary fats and of some medicine on blood viscosity and hemodynamics resembling BP have been reported. As a result of atherosclerotic vessels can not dilate sufficiently as a response to vasodilator medicine, it has been advised that elevated blood viscosity can solely be compensated with a BP improve in such circumstances.9–12 Additionally, the relationships amongst BP, headache, coagulation, blood stream velocity, and blood viscosity have been described by way of the rules of hemodynamics.13,14
The examine consisted of two teams. For the primary group, our intention was to measure the doable alterations in blood and plasma viscosity and erythrocyte deformability as a consequence of temperature adjustments on wholesome topics, and likewise to find out the adjustments of BP through the use of calculations primarily based upon the legislation of hemodynamics. As diameters of erythrocytes are bigger than these of capillaries, they'll solely go by way of capillaries by deforming. Such a form alteration capability of erythrocytes might be measured and outlined with the idea of deformability. The free stream time of erythrocyte mass by way of the viscometer is inversely proportional to erythrocyte deformability.15 Relationships amongst blood viscosity, erythrocyte deformability, temperature, and BP haven't but been reported.
The second group consisted of diabetes mellitus (DM) kind II sufferers with out diabetic problems. Our intention was to find out the connection between blood glucose and viscosity throughout an oral glucose tolerance check (OGTT), and to calculate the consequences of those elements on BP with the legislation of hydrodynamics. Diabetic sufferers had been chosen to analysis the connection between glucose and viscosity in a variety of blood glucose concentrations. Though the connection between blood glucose and viscosity has been proven, the connection between blood glucose and BP has not but been reported.16,17
Supplies and Strategies
For the primary group of the examine, a complete of 53 wholesome topics had been chosen by a easy random sampling technique. The examine inhabitants was chosen from the guests of our clinic's sufferers, who had no complaints and had not used any medicines for the final week. The group was made up of 36 males and 17 ladies with a imply age of 26.5 ± 6.5 years. For the second group, a complete of 29 topics who had uncomplicated DM and had not taken any medicines had been chosen by a easy random sampling technique from newly identified DM kind II sufferers at our division's diabetes mellitus outpatient clinic. Knowledgeable consent was obtained from all people collaborating within the examine.
Preparation of Blood Samples
After an in a single day fasting interval, a 9.9 mL blood pattern was collected from the brachial vein of each topic over 0.1 mL (500 IU) of heparin sodium. Every pattern was centrifuged at 3000 rpm for five min by a centrifuge with a 9.5 cm radius. The plasma was obtained as a supernatant and the buff-coat was thrown away. To separate the remaining erythrocyte sediment from leucocytes, it was blended with 5 mL of 0.9% NaCl answer and centrifuged twice by the identical technique.
Measurement of Viscosity and Deformability
Measurements had been made through the use of the straightforward capillary tube viscometer technique that has been utilized in our division since 1990.3,11,12,18 The viscometer had a reservoir on the higher half with a quantity of two mL. It was crammed within the vertical place with fluid pattern to the higher line of the reservoir, after which the free stream time of the pattern to the decrease line of the reservoir was measured in seconds (sec).
If the free stream time of distilled water is accepted as 1, the worth achieved by comparability to the free stream time of a pattern could also be termed as “relative viscosity”.
The viscometer was used on the chosen fixed laboratory circumstances in the identical vertical place and with out publicity to direct daylight or airflow. We used free stream time as a substitute of relative viscosity worth as information, to make the statistical and graphic estimates extra correct and to forestall rounding of the calculations.
The free stream occasions of blood, plasma, and erythrocyte mass had been decided at 22°, 36.5°, and 39.5°C. To forestall protein precipitation, the viscometer was used after it was washed with 0.9% sodium chloride answer, rinsed with distilled water, and dried with acetone. For examine at totally different temperatures, the viscometer was positioned in a clear, plastic enclosed bathtub system, wherein the 2 ends of the viscometer stood vertically and heat-controlled water was circulated constantly with a excessive output peristaltic pump within the bathtub system.
Erythrocyte deformability is the shape-changing capability of an erythrocyte. One of many strategies to measure deformability is willpower of erythrocyte passing time by way of a filter that has commonplace sized pores. Due to the distinction in erythrocyte diameter and quantity between people, the specificity and the sensitivity of this technique could also be inadequate.15 As a result of free stream time of pure erythrocyte mass represents erythrocyte deformability, fluidity, and inside viscosity, and since utilizing the viscometer to find out the erythrocyte free stream time was extra cheap and simpler, we most well-liked this technique and its information for the examine.
Measurement of Blood Glucose Focus
The blood glucose focus measurements had been made with an Accutrend GC glucometer (Boehringer Mannheim, Mannheim, Germany). At the very least 4 measurements of blood glucose and simultaneous measurements of blood and plasma viscosity had been made for the entire 29 circumstances at 0, 30, 60, and 120 min at 22°C, after ingestion of 75 g of glucose.
Outcomes of the primary group had been evaluated statistically with the Pupil t check and Spearman correlation check. The connection between blood glucose focus and viscosity was evaluated statistically through the use of the Pupil t check, evaluation of variance, and regression evaluation.
Relationship of Blood Temperature, Viscosity, and Strain
When the blood temperature decreased from 36.5° to 22°C, the imply blood free stream time elevated from 11.62 to 15.55 sec (26.13%). In line with Poiseuille's equation, the blood stream fee decreases 20.72%, and for the compensation of this ischemic state, a 26.13% BP improve or 5.9% vasodilation is required. If viscosity (η within the denominator of the equation) adjustments from 100 to 126.13 (26.13%), the stream fee Q would lower 100/126.13 = 20.72%. If viscosity will increase 26.13%, the stress (F1 − F2) worth (multiplier within the equation) should be elevated with the identical share to maintain the equation fixed. When the viscosity will increase 26.13%, to maintain the stream fee fixed, the radius of vessel (preliminary) a4, should improve 26.13%. The calculation of this elevated radius (last) is a4last = 1.2613 × a4preliminary. From this calculation, αlast = = 1.0597 and so, 5.97% vasodilation might be estimated.
When the temperature elevated from 36.5° to 39.5°C, the blood free stream time decreased from 11.59 to 10.58 sec (10.38%). On this state, the blood stream fee elevated 11.15%; in response to Poiseuille's equation, a 10.38% lower in BP or 2.71% vasoconstriction was wanted to maintain the hemodynamic equilibrium fixed.
The correlation between temperature and blood viscosity is r = −0.84, P < .001 when all of the variations on the three temperatures are evaluated collectively (Fig. 1). When the entire blood free stream time information for the three temperatures had been evaluated collectively in response to age, there was a detrimental correlation (r = −0.1381 and P < .05); when the information had been evaluated in response to intercourse, it was discovered that the imply blood free stream time in ladies was 12.97% lower than that in males (r = 0.3408, P < .001).
Impact of temperature on blood viscosity. When blood temperature decreases from 36.5° to 22°C, blood viscosity will increase 26.13%. If temperature will increase from 36.5° to 39.5°C, blood viscosity decreases 10.38%. To make a extra correct presentation within the graphic illustration and statistics, as a substitute of the “relative viscosity” worth, blood free stream time in seconds (s) was used as information. When the entire variations at three temperatures are evaluated collectively, a detrimental correlation is seen between blood temperature and viscosity (r = −0.84, P < .001).
When the temperature decreased from 36.5° to 22°C, plasma free stream time rose from 4.81 to five.71 sec (18.71%); with a temperature improve from 36.5° to 39.5°C, it decreased from 4.78 to 4.57 sec (4.99%). A detrimental correlation was seen (r = −0.9342, P < .001) when the plasma stream occasions on the three temperatures had been evaluated collectively. With a temperature lower from 36.5° to 22°C, erythrocyte free stream time elevated from 27.03 to 36.42 sec (34.73%). When the temperature elevated from 36.5° to 39.5°C, erythrocyte free stream time decreased from 27.02 to 24.35 sec (9.92%). There was a detrimental correlation between temperature and erythrocyte free stream time (r = −0.62, P < .001). The entire blood, plasma viscosity, and erythrocyte deformability variations as a consequence of temperature had been statistically vital (P < .001).
Relationship of Blood Glucose, Viscosity, and Strain
The correlation coefficient of blood glucose versus blood free stream time and plasma free stream time ranged from 0.59 to 0.49 and from 0.55 to 0.53, respectively. Regression traces had been drawn at no cost stream time of blood and plasma versus blood glucose concentrations, and their slopes didn't present any vital distinction. Thus, the beneath formulation had been derived from the equation y = ax + b: blood free stream time = (0.011)(blood glucose) + 12.10; plasma free stream time = (0.008)(blood glucose) + 5.4.
From these formulae, the calculated blood free stream time for a 100 mg/dL blood glucose focus was 13.2 sec, and plasma free stream time was 6.2 sec. For every 100 mg/dL improve in blood glucose focus, there was a 1.1 sec improve in blood free stream time and 0.Eight sec improve in plasma free stream time. At 400 mg/dL blood glucose focus, blood free stream time elevated from 13.2 to 16.5 sec (25%).
Within the regression evaluation, the next values had been calculated: F = 11.59, P = .002 (P < .05) for blood free stream time and F = 14.6, P = .0007 (P < .05) for plasma free stream time. The squared a number of correlation coefficient (R2) worth was 0.35, which means that there was a 35% impact of the blood glucose on the blood free stream time.
The connection between the blood and the plasma viscosity values versus glucose concentrations are represented on scatterplots with regression traces in Fig. 2. Vital will increase in glucose focus and viscosity values (free stream time) of blood and plasma had been noticed (P < .05). In line with Poiseuille's equation, a 25% improve in viscosity leads to a 20% lower in blood stream fee. For the physiological compensation of this ischemic state, a 25% improve in BP or a 5.7% vasodilatation was required.
Illustration of the function of blood glucose on blood viscosity on scatter diagram with regression traces. Adjustments within the values of the blood free stream time and the plasma free stream time had been measured with the capillary viscometer in seconds and used as the information towards blood glucose concentrations of oral glucose tolerance check (in mg/dL). Correlation coefficient of blood glucose versus blood viscosity and plasma viscosity ranges ranged from 0.59 to 0.49 (P = .002) and from 0.55 to 0.53 (P = .0007), respectively.
The Impact of Temperature on Blood Strain
The noticed BP improve of 26.13% associated to decreased temperature and elevated viscosity should be clinically vital. As the primary purpose of the management system of blood circulation is protecting the blood stream quantity at a continuing and ample fee, a few of the excessive BP measured in sufferers could also be as a consequence of physiological compensation of decreased blood stream fee.
The temperature of the decrease extremities in regular circumstances is roughly 25°C,19 and the temperatures of the extremities, face, lungs, and different elements of the physique can lower in chilly climate. This example can result in decreased blood stream fee as a consequence of elevated blood viscosity, and may clarify the coronary angina and exertion problem noticed in a chilly surroundings. An identical state is medical hibernation, wherein blood temperature falls to 22°C. As a result of atherosclerotic vessels can not dilate and sufficiently reply to vasodilator medicine, BP improve could also be the primary mechanism for prevention of ischemia in some sufferers.20–24 The chance for ischemia might be elevated in a chilly surroundings if sufferers are hypertensive and don't have any reserve capability of BP improve to compensate the circulatory load. In these sufferers, lowering viscosity through the use of applicable medicine ought to achieve significance.11,12
The stress lower of 10.38% as a consequence of a temperature improve to 39.5°C should be clinically vital. This data can clarify some scientific conditions resembling hypotension assaults noticed in scorching environments, and fever-related tachycardia, which is the early physiological compensatory reflex for decreased BP.19 Moreover, protecting the physique temperature at about 39.5°C throughout a marathon run might carry a circulatory benefit to an athlete by growing the blood stream fee by way of decreased viscosity. The ability achieve of athletes earlier than competitors by warm-up workout routines might be thought of for instance supporting this level. As lowering blood viscosity has an impact just like lowering the peripheral resistance of circulation, blood temperature turns into an vital issue for peripheral resistance and BP. The stream chart in Fig. Three reveals the relationships amongst BP, viscosity, and temperature.
Presentation in a stream chart of the stoichiometric relations of the adjustments within the blood viscosity, stream fee, stress, and vessel diameter with the altering blood temperature.
The above calculations and interpretations might be made for the noticed relationships amongst temperature, plasma viscosity, and erythrocyte deformability.
The Impact of Glucose on Blood Strain
We confirmed that BP should improve 25% to compensate the decreased blood stream fee as a consequence of hyperviscosity seen with hyperglycemia at 400 mg/dL, and this discovering should be clinically vital.
After an insulin-resistant state had been proven in important hypertension,25 Resnick et al reported that in regular and hypertensive sufferers, growing glucose concentrations raised intracellular calcium ion concentrations in erythrocytes.26 Then, Barbagallo et al demonstrated that hyperglycemia might underlie the predisposition to hypertension and vascular illnesses amongst diabetic topics by growing the intracellular free calcium concentrations in vascular easy muscle cells.27
As a result of vascular problems and atherosclerosis are extra widespread in DM, these outcomes might be utilized in some scientific conditions.28,29 For diabetics and for diabetics with atherosclerosis, BP improve would be the solely doable or dominant compensation mechanism of decreased blood stream fee as a consequence of hyperglycemic hyperviscosity, due to inadequate vasodilation led by elevated intracellular calcium focus and atherosclerosis. Excessive BP in a affected person who's admitted to the emergency service with hyperglycemic coma can in reality be a physiological response to compensate the ischemia. A speedy and uncontrolled lower in BP in such a affected person earlier than therapy of hyperglycemia can result in a sudden fall in blood stream fee, which suggests acute tissue ischemia. Hyperglycemic hyperviscosity might be one clarification for the postprandial exertion problem. For the adjustment of antihypertensive medicine, BP measurements underneath normoglycemic circumstances shouldn't be ignored.
These relationships amongst blood stream fee, glucose, viscosity, stress, and vasodilatation capacities are proven as a system evaluation on a stream chart in Fig. 4.
In line with Hagen-Poiseuille Hydrodynamics Legislation and our examine outcomes, stoichiometric relations between BP, viscosity, glucose, stream fee, and vessel diameter might be proven as a organic system evaluation in a stream chart.
On this examine, we stoichiometrically confirmed that temperature and hyperglycemia have an vital impact on blood viscosity and BP. In line with this data, the mechanism of chilly climate angina, peripheric resistance, tachycardia, and hypotension in scorching climate, postprandial exertion problem, and physiological achieve with warm-up workout routines and with temperature improve might be defined on a brand new foundation. The data in our examine will increase the variety of hemodynamic parameters and ought to be thought of within the therapy and follow-up of sufferers with hypertension and evaluation of the circulatory system.