Noradrenaline and Nω-monomethyl-L-arginine (L-NMMA): effects on haemodynamics and regional blood flow in healthy and septic sheep

2000 ◽  
Vol 98 (2) ◽  
pp. 193-200 ◽  
Author(s):  
M. BOOKE ◽  
F. HINDER ◽  
R. MCGUIRE ◽  
L. D. TRABER ◽  
D. L. TRABER
Keyword(s):  
Blood Pressure ◽  
Experimental Study ◽  
Pseudomonas Aeruginosa ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Cardiac Index ◽  
Urine Output ◽  
Regional Blood Flow ◽  
Randomized Controlled ◽  
Vascular Responsiveness

This prospective, non-randomized, controlled experimental study looks at the effects of NΩ-monomethyl-l-arginine (l-NMMA) on haemodynamics, oxygen transport and regional blood flow in healthy and septic sheep, and compares these effects with those of noradrenaline (NA; norepinephrine). All sheep were chronically instrumented. Six sheep received l-NMMA (7 mg·kg-1·h-1), six sheep received NA, and seven sheep received the carrier alone (0.9% NaCl). The NA dosage was continuously and individually adjusted to achieve the same increase in blood pressure as observed in matched sheep of the l-NMMA group (non-septic phase). Treatment was discontinued after 3 h. Sepsis was initiated and maintained by a continuous infusion of live Pseudomonas aeruginosa. After 24 h of sepsis, the sheep were again challenged over a treatment period of 3 h with their previously assigned drug (septic phase). During the non-septic phase of the experiment, NA and l-NMMA both caused an increase in mean arterial pressure (MAP) through vasoconstriction. Ater 24 h of sepsis, all sheep developed a hyperdynamic circulatory state. While l-NMMA caused an increase in MAP through intense vasoconstriction, NA caused MAP to increase through a further elevation of the cardiac index. The NA dosage needed was significantly higher in the septic phase compared with the non-septic phase, reflecting a reduced vascular responsiveness to catecholamines during sepsis. Renal blood flow remained unchanged during either treatment in both the non-septic and the septic phases. Nevertheless, urine output increased during NA treatment in both the non-septic and the septic phases, while l-NMMA caused urine output to increase only under septic conditions.

scholarly journals Changes in hemodynamics, renal blood flow and urine output during continuous renal replacement therapies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
S. N. Fernández ◽  
M. J. Santiago ◽  
R. González ◽  
J. López ◽  
M. J. Solana ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Index ◽  
Renal Blood Flow ◽  
Urine Output ◽  
Venous Pressure ◽  
Kidney Injury ◽  
Renal Replacement Therapies ◽  
Continuous Renal Replacement Therapies ◽  
The Impact

AbstractContinuous renal replacement therapies (CRRT) affect hemodynamics and urine output. Some theories suggest a reduced renal blood flow as the cause of the decreased urine output, but the exact mechanisms remain unclear. A prospective experimental study was carried out in 32 piglets (2–3 months old) in order to compare the impact of CRRT on hemodynamics, renal perfusion, urine output and renal function in healthy animals and in those with non-oliguric acute kidney injury (AKI). CRRT was started according to our clinical protocol, with an initial blood flow of 20 ml/min, with 10 ml/min increases every minute until a goal flow of 5 ml/kg/min. Heart rate, blood pressure, central venous pressure, cardiac output, renal blood flow and urine output were registered at baseline and during the first 6 h of CRRT. Blood and urine samples were drawn at baseline and after 2 and 6 h of therapy. Blood pressure, cardiac index and urine output significantly decreased after starting CRRT in all piglets. Renal blood flow, however, steadily increased throughout the study. Cisplatin piglets had lower cardiac index, higher vascular resistance, lower renal blood flow and lower urine output than control piglets. Plasma levels of ADH and urine levels of aquaporin-2 were lower, whereas kidney injury biomarkers were higher in the cisplatin group of piglets. According to our findings, a reduced renal blood flow doesn’t seem to be the cause of the decrease in urine output after starting CRRT.

The Impact of several Antihypertensive drugs and Medicinal herbs on Induced hypertension in rabbits

2021 ◽  
pp. 4832-4836
Author(s):  
Hayder Sabah Hasan ◽  
Imad Hashim ◽  
Zaid Al-Attar
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Medicinal Plants ◽  
Urine Output ◽  
Effective Drug ◽  
Aqueous Extracts ◽  
Plantago Major ◽  
Induced Hypertension ◽  
Teucrium Polium ◽  
The Impact

Objective: To assess the antihypertensive efficacy of the medicinal plants used Hibiscus subdariffa, Plantago major, Teucrium polium. Moreover, we aim to Investigate the mechanisms of actions of tested agents. Design: Induced hypertension in experimental animals is tested against several drugs and medicinal plants extracts. Animals and materials: Hypertension was induced in experimental rabbits with phenylephrine 0.2mg/kg i.v. with increasing the dose (until Blood pressure>130/90mmHg). Rabbits were divided to 7 groups: Control, atenolol, furosemide, candesartan, Hibiscus subdariffa, Plantago major, Teucrium polium. ANOVA with Dunnett's test was implemented for statistical calculations with p<0.05 as significance level. Results: Candesartan was the most effective in lowering both systolic and diastolic blood pressure. Concerning the blood flow, candesartan was found to be the most significantly effective drug in increasing blood flow followed by furosemide and Hibiscus subdariffa respectively. Concerning the urine output furosemide was found to be the most significantly effective drug in increasing urine output followed by Hibiscus subdariffa. The aqueous extracts of Plantago major and Teucrium polium showed no significant effect. Conclusions: Hibiscus subdariffa is effective as diuretic agent at the concentration mentioned. Its action involves diuretic and vasodilator effect. While aqueous extracts of Plantago major and Teucrium polium are not effective.

Increased vascular resistance in paralyzed legs after spinal cord injury is reversible by training

2002 ◽  
Vol 93 (6) ◽  
pp. 1966-1972 ◽  
Author(s):  
Maria T. E. Hopman ◽  
Jan T. Groothuis ◽  
Marcel Flendrie ◽  
Karin H. L. Gerrits ◽  
Sibrand Houtman
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Cord Injury

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

Direct Cerebral Vasodilatory Effects of Sevoflurane and Isoflurane 

1999 ◽  
Vol 91 (3) ◽  
pp. 677-677 ◽  
Author(s):  
Basil F. Matta ◽  
Karen J. Heath ◽  
Kate Tipping ◽  
Andrew C. Summors
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
End Tidal

Background The effect of volatile anesthetics on cerebral blood flow depends on the balance between the indirect vasoconstrictive action secondary to flow-metabolism coupling and the agent's intrinsic vasodilatory action. This study compared the direct cerebral vasodilatory actions of 0.5 and 1.5 minimum alveolar concentration (MAC) sevoflurane and isoflurane during an propofol-induced isoelectric electroencephalogram. Methods Twenty patients aged 20-62 yr with American Society of Anesthesiologists physical status I or II requiring general anesthesia for routine spinal surgery were recruited. In addition to routine monitoring, a transcranial Doppler ultrasound was used to measure blood flow velocity in the middle cerebral artery, and an electroencephalograph to measure brain electrical activity. Anesthesia was induced with propofol 2.5 mg/kg, fentanyl 2 micro/g/kg, and atracurium 0.5 mg/kg, and a propofol infusion was used to achieve electroencephalographic isoelectricity. End-tidal carbon dioxide, blood pressure, and temperature were maintained constant throughout the study period. Cerebral blood flow velocity, mean blood pressure, and heart rate were recorded after 20 min of isoelectric encephalogram. Patients were then assigned to receive either age-adjusted 0.5 MAC (0.8-1%) or 1.5 MAC (2.4-3%) end-tidal sevoflurane; or age-adjusted 0.5 MAC (0.5-0.7%) or 1.5 MAC (1.5-2%) end-tidal isoflurane. After 15 min of unchanged end-tidal concentration, the variables were measured again. The concentration of the inhalational agent was increased or decreased as appropriate, and all measurements were repeated again. All measurements were performed before the start of surgery. An infusion of 0.01% phenylephrine was used as necessary to maintain mean arterial pressure at baseline levels. Results Although both agents increased blood flow velocity in the middle cerebral artery at 0.5 and 1.5 MAC, this increase was significantly less during sevoflurane anesthesia (4+/-3 and 17+/-3% at 0.5 and 1.5 MAC sevoflurane; 19+/-3 and 72+/-9% at 0.5 and 1.5 MAC isoflurane [mean +/- SD]; P&lt;0.05). All patients required phenylephrine (100-300 microg) to maintain mean arterial pressure within 20% of baseline during 1.5 MAC anesthesia. Conclusions In common with other volatile anesthetic agents, sevoflurane has an intrinsic dose-dependent cerebral vasodilatory effect. However, this effect is less than that of isoflurane.

scholarly journals Impact of blood pressure changes in cerebral blood perfusion of patients with ischemic Moyamoya disease evaluated by SPECT

2020 ◽  
pp. 0271678X2096745
Author(s):  
Zhao Liming ◽  
Sun Weiliang ◽  
Jia Jia ◽  
Liang Hao ◽  
Liu Yang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Moyamoya Disease ◽  
Emission Computed Tomography ◽  
Study Cohort ◽  
Pressure Changes ◽  
The Impact

Our aim was to determine the impact of targeted blood pressure modifications on cerebral blood flow in ischemic moyamoya disease patients assessed by single-photon emission computed tomography (SPECT). From March to September 2018, we prospectively collected data of 154 moyamoya disease patients and selected 40 patients with ischemic moyamoya disease. All patients underwent in-hospital blood pressure monitoring to determine the mean arterial pressure baseline values. The study cohort was subdivided into two subgroups: (1) Group A or relative high blood pressure (RHBP) with an induced mean arterial pressure 10–20% higher than baseline and (2) Group B or relative low blood pressure (RLBP) including patients with mean arterial pressure 10–20% lower than baseline. All patients underwent initial SPECT study on admission-day, and on the following day, every subgroup underwent a second SPECT study under their respective targeted blood pressure values. In general, RHBP patients showed an increment in perfusion of 10.13% (SD 2.94%), whereas RLBP patients showed a reduction of perfusion of 12.19% (SD 2.68%). Cerebral blood flow of moyamoya disease patients is susceptible to small blood pressure changes, and cerebral autoregulation might be affected due to short dynamic blood pressure modifications.

Effects of oxygen on regional hemodynamics in hemorrhagic shock

1996 ◽  
Vol 271 (1) ◽  
pp. H203-H211 ◽  
Author(s):  
H. Bitterman ◽  
V. Brod ◽  
G. Weisz ◽  
D. Kushnir ◽  
N. Bitterman
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Hemorrhagic Shock ◽  
Vascular Resistance ◽  
Regional Blood Flow ◽  
Biceps Femoris ◽  
Total Blood ◽  
Biceps Femoris Muscle ◽  
Arterial Blood ◽  
Femoris Muscle

This study investigated mechanisms of the hemodynamic effects of oxygen in hemorrhagic shock induced by bleeding 30% of the total blood volume in anesthetized rats. An ultrasonic flowmeter was used to monitor regional blood flow. Changes in tissue perfusion were assessed by the laser-Doppler technique. The inhalation of 100% oxygen induced a significant increase in mean arterial blood pressure (MABP) and vascular resistance in the hindquarters, with a concomitant decrease in blood flow in the distal aorta and biceps femoris muscle. In contrast, oxygen did not change vascular resistance in the superior mesenteric artery (SMA) and renal beds and induced a significant increase in blood flow to the renal artery, SMA, and small bowel in hemorrhaged rats. L-Arginine (100 mg/kg iv) but not D-arginine or the vehicle (0.9% NaCl) completely abolished the effects of oxygen on blood pressure and reversed its effects on blood flow and resistance in the hindquarters and biceps femoris muscle. Administration of the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (50 mg/kg iv) significantly increased MABP and the resistance in the three vascular beds. Pretreatment of hemorrhaged rats with a superoxide dismutase mimic, the NO-stable radical 2,2,6,6-tetramethylpiperidine-N-oxyl (5 mg/kg iv), resulted in significantly diminished effects of oxygen on hindquarter hemodynamics. These results demonstrate a differential effect of oxygen, which increases vascular resistance in the hindquarters without a significant effect in the splanchnic and renal beds, thus favoring an increase in splanchnic and renal perfusion. It is suggested that inactivation of NO by reactive oxygen species may underlie the effects of oxygen on hindquarter vascular tone during shock.

Age-related changes in regional blood flow in the rat

1985 ◽  
Vol 249 (3) ◽  
pp. H485-H491 ◽  
Author(s):  
R. F. Tuma ◽  
G. L. Irion ◽  
U. S. Vasthare ◽  
L. A. Heinel
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Cardiac Index ◽  
Regional Blood Flow ◽  
Adult Rats ◽  
Blood Flows ◽  
Arterial Blood ◽  
Anesthetized Rats ◽  
Regional Blood Flows ◽  
Central Hemodynamic

The purpose of this investigation was to characterize the changes in regional blood flow and central hemodynamic measures that occur in the rat as a result of the aging process. The isotope-labeled microsphere technique was used to measure cardiac output and regional blood flows in conscious and anesthetized adult (12 mo) and senescent (24 mo) Fischer 344 virgin female rats. No significant changes were observed in central hemodynamic measurements or regional blood flows in conscious rats with the exception of a 25% reduction in splenic blood flow. Pentobarbital anesthesia significantly reduced cardiac index and heart rate but elevated total peripheral resistance and mean arterial blood pressure. There was a decrease in blood flow to skeletal muscle, spleen, duodenum, stomach, and brain tissue samples and increased hepatic arterial blood flow in both age groups. The use of anesthesia caused a greater reduction in the cardiac index and brain blood flow in the senescent anesthetized rats than in the adult rats. Heart and kidney blood flows were decreased by anesthesia in the senescent rats but not in the adult rats. Skeletal muscle blood flow, however, was significantly greater in the senescent anesthetized rats than in the younger anesthetized animals. Although body weight and organ weights of the liver, spleen, kidneys, stomach, heart, and brain were significantly greater for the senescent rats, no differences could be demonstrated in tibial length or lean body mass.

Evidence for Peripheral Vascular Involvement in Mild Elevation of Blood Pressure in Man

1976 ◽  
Vol 51 (s3) ◽  
pp. 65s-68s
Author(s):  
R. Sivertsson ◽  
R. Sannerstedt ◽  
Y. Lundgren
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Index ◽  
Structural Changes ◽  
Vascular Involvement ◽  
Control Group ◽  
Study Group ◽  
Blood Pressure Elevation ◽  
Pressure Elevation ◽  
Arterial Blood

1. Cardiac output at rest, intra-arterial blood pressure and hand blood flow at maximal vasodilatation were studied in two groups of 18–25-year-old men: forty-four with mild blood pressure elevation were referred from a military enlistment centre, and twenty-nine normotensive volunteers were mainly recruited from the same enlistment centre. 2. The study group was characterized by a significantly higher cardiac index at rest, and a significantly higher blood flow resistance in the hand at maximal vasodilatation than the control group, indicating the presence of structural modifications in the resistance vessels of patients with mild blood pressure elevation. 3. The tendency to increased vascular resistance in the blood vessels of the hand at maximal vasodilatation was more pronounced in patients with a normal cardiac index than in those with a high index. This suggests inclusion in the study group of tense, anxious individuals with an elevated cardiac index but otherwise normal circulation, but does not exclude the possibility that these patients may develop structural changes later on.

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