Models of Tissue Oxygen Uptake and Microcirculatory Blood Flow

2001 ◽  
pp. 146-177
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Tissue Oxygen ◽  
Microcirculatory Blood Flow

scholarly journals Hypotension during Fluid-restricted Abdominal Surgery

2011 ◽  
Vol 114 (3) ◽  
pp. 557-564 ◽  
Author(s):  
Luzius B. Hiltebrand ◽  
Eliana Koepfli ◽  
Oliver Kimberger ◽  
Gisli H. Sigurdsson ◽  
Sebastian Brandt
Keyword(s):  
Blood Flow ◽  
Abdominal Surgery ◽  
Oxygen Tension ◽  
Intestinal Tract ◽  
Tissue Oxygen Tension ◽  
Control Group ◽  
Tissue Oxygen ◽  
Microcirculatory Blood Flow ◽  
Intestinal Tissue ◽  
Doppler Flowmetry

Background Vasopressors, such as norepinephrine, are frequently used to treat perioperative hypotension. Increasing perfusion pressure with norepinephrine may increase blood flow in regions at risk. However, the resulting vasoconstriction could deteriorate microcirculatory blood flow in the intestinal tract and kidneys. This animal study was designed to investigate the effects of treating perioperative hypotension with norepinephrine during laparotomy with low fluid volume replacement. Methods Twenty anesthetized and ventilated pigs were randomly assigned to a control or treatment (norepinephrine) group. Both groups received 3 ml · kg⁻¹ · h⁻¹ Ringer's lactate solution. In addition, the norepinephrine group received norepinephrine to stepwise increase blood pressure to 65 and 75 mmHg. Regional blood flow was measured in the splanchnic arteries. In the small bowel and colon, microcirculatory blood flow was measured using laser Doppler flowmetry. Intestinal tissue oxygen tension was measured with intramural Clark-type electrodes. Results Hepatosplanchnic and kidney blood flow remained unchanged after reversal of arterial hypotension to a mean arterial pressure of 75 mmHg with norepinephrine. For the norepinephrine group versus the control group, the mean ± SD microcirculatory blood flow in the jejunum (96 ± 41% vs. 93 ± 18%) and colon (98 ± 19% vs. 97 ± 28%) and intestinal tissue oxygen tension (jejunum, 45 ± 13 vs. 43 ± 5 mmHg; colon, 50 ± 10 vs. 45 ± 8 mmHg) were comparable. Conclusions In this model of abdominal surgery in which clinical conditions were imitated as close as possible, treatment of perioperative hypotension with norepinephrine had no adverse effects on microcirculatory blood flow or tissue oxygen tension in the intestinal tract.

scholarly journals Oxygen Homeostasis and Mitochondrial Function in COVID-19 and ARDS Patients: The Ultimate Vital Signs

2020 ◽  
Keyword(s):  
Blood Flow ◽  
Real Time ◽  
Mitochondrial Function ◽  
Vital Signs ◽  
The Body ◽  
Oxygen Balance ◽  
Tissue Oxygen ◽  
Microcirculatory Blood Flow ◽  
Oxygen Homeostasis ◽  
Hemoglobin Oxygenation

The leading cause of death from the COVID-19 is the development of Pneumonia and Acute Respiratory Distress Syndrome-ARDS. Advanced physiological monitoring of COVID -19 patients in real time is a missing tool that avoid the optimization of better diagnosis and evaluating the efficacy of the treatment given. As of today, the monitoring of the systemic vital signs provides important information regarding the respiratory and cardiovascular systems including the pulse oximetry that provide data on hemoglobin oxygenation in the macro circulation. Our hypothesis is that the pathophysiology of COVID-19 and ARDS patients includes severe changes in the microcirculatory hemodynamics and cellular disturbances in Tissue and cellular Oxygen Homeostasis. Therefore, we postulate that real time monitoring of mitochondrial NADH redox state and microcirculatory blood flow, volume and hemoglobin oxygenation is the missing information that will affect dramatically the outcome of COVID-19 and ARDS patients. During the last 2 decades we studied the mechanism of blood flow redistribution activated in animal models as well as in patients exposed to total body negative oxygen balance. This mechanism is activated by the sympathetic pathway. This effect is not equal in all organs of the body, namely, in the most vital organs - brain, heart, and adrenal glands oxygen supply is preserved while in the less vital organs (visceral and peripheral organs) hypo perfusion and negative oxygen balance is recorded. In order to evaluate the tissue oxygen homeostasis, we developed a new concept named - LifenLight Score (LLS)TM based on the monitoring of four physiological parameters measured in real time from one of the less vital organs in the body. Our developed device is monitoring mitochondrial function by measuring the NADH auto fluorescence and microcirculatory blood flow, tissue reflectance and hemoglobin oxygenation. In animal model we monitored simultaneously the brain and the small intestine. In patients we used a 3-way Foley catheter introduced to the bladder via the urethra. We found that monitoring the less vital organ could serve as an early warning signal to the development of negative oxygen balance in the body as well as indicate of a recovery process in the improvement of the oxygen balance homeostasis. In conclusion, we hypothesize that using our new monitoring system will be able to detect deterioration process related to hypoxia in COVID-19 and ARDS patients, as well as to monitor improvement in tissue oxygen balance due to various treatments such as exposure to hyperoxia.

scholarly journals Goal-directed Colloid Administration Improves the Microcirculation of Healthy and Perianastomotic Colon

2009 ◽  
Vol 110 (3) ◽  
pp. 496-504 ◽  
Author(s):  
Oliver Kimberger ◽  
Michael Arnberger ◽  
Sebastian Brandt ◽  
Jan Plock ◽  
Gisli H. Sigurdsson ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Tension ◽  
Fluid Therapy ◽  
Group Versus ◽  
Tissue Oxygen Tension ◽  
Colon Anastomosis ◽  
Tissue Oxygen ◽  
Microcirculatory Blood Flow ◽  
Crystalloid Fluid ◽  
Group 3

Background The aim of this study was to compare the effects of goal-directed colloid fluid therapy with goal-directed crystalloid and restricted crystalloid fluid therapy on healthy and perianastomotic colon tissue in a pig model of colon anastomosis surgery. Methods Pigs (n = 27, 9 per group) were anesthetized and mechanically ventilated. A hand-sewn colon anastomosis was performed. The animals were subsequently randomized to one of the following treatments: R-RL group, 3 ml x kg(-1) x h(-1) Ringer lactate (RL); GD-RL group, 3 ml x kg(-1) x h(-1) RL + bolus 250 ml of RL; GD-C group, 3 ml x kg(-1) x h(-1) RL + bolus 250 ml of hydroxyethyl starch (HES 6%, 130/0.4). A fluid bolus was administered when mixed venous oxygen saturation dropped below 60%. Intestinal tissue oxygen tension and microcirculatory blood flow were measured continuously. Results After 4 h of treatment, tissue oxygen tension in healthy colon increased to 150 +/- 31% in group GD-C versus 123 +/- 40% in group GD-RL versus 94 +/- 23% in group R-RL (percent of postoperative baseline values, mean +/- SD; P < 0.01). Similarly perianastomotic tissue oxygen tension increased to 245 +/- 93% in the GD-C group versus 147 +/- 58% in the GD-RL group and 116 +/- 22% in the R-RL group (P < 0.01). Microcirculatory flow was higher in group GD-C in healthy colon. Conclusions Goal-directed colloid fluid therapy significantly increased microcirculatory blood flow and tissue oxygen tension in healthy and injured colon compared to goal-directed or restricted crystalloid fluid therapy.

Intestinal blood flow and oxygen uptake in the neonatal piglet during reduced perfusion pressure

1987 ◽  
Vol 252 (2) ◽  
pp. G190-G194
Author(s):  
P. T. Nowicki ◽  
N. B. Hansen ◽  
J. A. Menke
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Vascular Resistance ◽  
Perfusion Pressure ◽  
Intestinal Blood Flow ◽  
Base Line ◽  
Pressure Reduction ◽  
Tissue Oxygen ◽  
Newborn Piglets ◽  
Severe Reduction

The effect of reduced perfusion pressure on neonatal intestinal blood flow, vascular resistance, arterio-venous oxygen content (a-v O2), and oxygen uptake was studied in nine fasted newborn piglets, aged 5-6 days. Successive reductions of intestinal perfusion pressure were achieved by a clamp on the thoracic aorta. Intestinal blood flow decreased after each reduction of perfusion pressure. Intestinal vascular resistance increased and Gf, a measure of flow control, was negative after all but the final, most severe reduction of perfusion pressure. However, intestinal a-v O2 increased after each pressure reduction and intestinal oxygen uptake was thus maintained at greater than or equal to 95% of its baseline value until perfusion pressure was reduced to less than or equal to 70% of its base-line value. The neonatal intestine maintains tissue oxygen uptake during moderate hypotension, and this is accomplished by regulation of a-v O2, rather than by regulation of blood flow.

Ventilatory threshold is related to walking tolerance in patients with intermittent claudication

VASA ◽  
2012 ◽  
Vol 41 (4) ◽  
pp. 275-281 ◽  
Author(s):  
da Rocha Chehuen ◽  
G. Cucato ◽  
P. dos Anjos Souza Barbosa ◽  
A. R. Costa ◽  
M. Ritti-Dias ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Intermittent Claudication ◽  
Lower Limb ◽  
Ventilatory Threshold ◽  
Reactive Hyperemia ◽  
Ankle Brachial Index ◽  
Metabolic Parameters ◽  
Walking Distance ◽  
The Relationship

Background: This study assessed the relationship between lower limb hemodynamics and metabolic parameters with walking tolerance in patients with intermittent claudication (IC). Patients and methods: Resting ankle-brachial index (ABI), baseline blood flow (BF), BF response to reactive hyperemia (BFRH), oxygen uptake (VO2), initial claudication distance (ICD) and total walking distance (TWD) were measured in 28 IC patients. Pearson and Spearman correlations were calculated. Results: ABI, baseline BF and BF response to RH did not correlate with ICD or TWD. VO2 at first ventilatory threshold and VO2peak were significantly and positively correlated with ICD (r = 0.41 and 0.54, respectively) and TWD (r = 0.65 and 0.71, respectively). Conclusions: VO2peak and VO2 at first ventilatory threshold, but not ABI, baseline BF and BFHR were associated with walking tolerance in IC patients. These results suggest that VO2 at first ventilatory threshold may be useful to evaluate walking tolerance and improvements in IC patients.

scholarly journals The use of pulse pressure variation for predicting impairment of microcirculatory blood flow

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christoph R. Behem ◽  
Michael F. Graessler ◽  
Till Friedheim ◽  
Rahel Kluttig ◽  
Hans O. Pinnschmidt ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Reperfusion Injury ◽  
Pulse Pressure ◽  
Pulse Pressure Variation ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Pressure Variation ◽  
Volume Loading ◽  
Microcirculatory Blood Flow

AbstractDynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg−1 bodyweight−1. Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min−1) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.

EFFECT OF INCREASED INTRA-ABDOMINAL PRESSURE ON HEPATIC ARTERIAL, PORTAL VENOUS, AND HEPATIC MICROCIRCULATORY BLOOD FLOW

1992 ◽  
Vol 33 (2) ◽  
pp. 279-283 ◽  
Author(s):  
Lawrence N. Diebel ◽  
Robert F. Wilson ◽  
Scott A. Dulchavsky ◽  
Jonathan Saxe
Keyword(s):  
Blood Flow ◽  
Abdominal Pressure ◽  
Microcirculatory Blood Flow

Local blood flow, oxygen tension, and oxygen consumption in the rat spinal cord

1983 ◽  
Vol 58 (4) ◽  
pp. 526-530 ◽  
Author(s):  
Nariyuki Hayashi ◽  
Barth A. Green ◽  
Mayra Gonzalez-Carvajal ◽  
Joseph Mora ◽  
Richard P. Veraa
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Oxygen Tension ◽  
Tissue Oxygen ◽  
Local Blood Flow ◽  
Rat Spinal Cord ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Tissue Oxygen Consumption

✓ Using a reliable and reproducible microelectrode technique, consistent simultaneous measurements of local spinal cord blood flow (SCBF), tissue oxygen tension, and tissue oxygen consumption were made at cervical, thoracic, and lumbar levels in the rat spinal cord. These observations showed that the metabolic state is maintained constant along the cord, despite significant variations in vasculature. The physiological and anatomical aspects of these findings are discussed.

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