Mechanisms of Polymyxin B Endotoxin Removal from Extracorporeal Blood Flow: Hydrodynamics of Sorption

2010 ◽  
pp. 55-64 ◽  
Author(s):  
G.B. Fiore ◽  
M. Soncini ◽  
S. Vesentini ◽  
A. Redaelli
Keyword(s):  
Blood Flow ◽  
Polymyxin B ◽  
Extracorporeal Blood

scholarly journals Flow manipulation and the association with myocardial contractility during extracorporeal life support (FLAME)

2021 ◽  
Vol 10 (Supplement_1) ◽  
Author(s):  
SKT Ma ◽  
WC Sin ◽  
CW Ngai ◽  
ASK Wong ◽  
WM Chan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiogenic Shock ◽  
Myocardial Contractility ◽  
Life Support ◽  
Extracorporeal Life Support ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Contractility ◽  
Left Ventricular Contractility ◽  
Extracorporeal Blood

Abstract Funding Acknowledgements Type of funding sources: None. Background Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is an advanced technique in extracorporeal life support (ECLS) used to support extreme circulatory failure including patients with cardiac arrest and cardiogenic shock refractory to conventional support. It is a long-standing belief that peripheral V-A ECMO poses increased afterload to the inured heart, but conventional echocardiographic measurements are often insensitive in detecting subtle changes in loading conditions. Purpose This study aimed to evaluate the effects of varying blood flow during peripheral V-A ECMO on intrinsic myocardial contractility, using detailed echocardiographic assessment including speckle tracking echocardiography (STE). Methods Adult patients with acute cardiogenic shock who were supported by peripheral V-A ECMO from April 2019 to September 2020 were recruited. Serial hemodynamic and cardiac performance parameters were measured by transthoracic echocardiogram (TTE) within 48 hours after implementation of V-A ECMO, at different levels of extracorporeal blood flow – 100%, 120% and 50% of target blood flow (TBF). Results A total of 30 patients were included. 22 (71%) were male, and the mean (SD) age was 54 (13) years. The major indications for V-A ECMO were myocardial infarction (19, 63% patients), and myocarditis (5, 17%). With a decrease in extracorporeal blood flow from 100% to 50% of TBF, mean arterial pressure (MAP) dropped from 76+/-3 to 64+/-3mmHg (p <0.001), and cardiac index (CI) increased from 0.89+/-0.13 to 1.27+/-0.18L/min/m2 (p < 0.001). All indices of left ventricular contractility improved at a lower extracorporeal blood flow: the myocardial contractility measured by global longitudinal peak systolic strain (GLPSS) improved from -3+/-0.7% to -5+/-0.8% (p < 0.001); left ventricular ejection fraction (LVEF) increased from 21.5+/-2.6% to 30.9+/-2.7% (p < 0.001) and 19.7+/-3.1% to 28.4+/-3.2% (p < 0.001) by biplane and linear methods, respectively; left ventricular index of myocardial performance (LIMP) improved from 1.51+/-0.12 to 1.03+/-0.09 (p < 0.001). Similar findings were reproduced when comparing left ventricular contractility at extracorporeal blood flows of 120% and 50% of TBF. Conclusions The ECMO blood flow rate in peripheral V-A ECMO is inversely related to myocardial contractility, and is quantifiable by myocardial strain measured by STE.

Blood Flow Rate and Access Recirculation in Hemodialysis

1992 ◽  
Vol 15 (8) ◽  
pp. 470-474 ◽  
Author(s):  
I.D. Daniels ◽  
G.M. Berlyne ◽  
R.H. Barth
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Blood Flow Rate ◽  
Hemodialysis Patients ◽  
Blood Pump ◽  
Concomitant Increase ◽  
Urea Clearance ◽  
Extracorporeal Blood

We studied the effect of extracorporeal blood flow rate (BFR) on access recirculation (recirc) in 19 hemodialysis patients. BUN was determined in simultaneous peripheral (P), arterial (A), and venous (V) blood obtained at BFRs of 200, 400 and 600 ml/min. Percent recirc was calculated for each BFR using the formula (P-A) / (P-V) X 100. Venous drip-chamber (VP) and pre-blood-pump (AP) pressures were measured at each BFR. Fistulograms were performed in 10 patients, and stenoses were identified in 5, all at the proximal (arterial) end of the access. Recirc increased with increasing BFR from 200 to 400 ml/min but increased little from 400 to 600 ml/min. At all BFRs recirc in the stenotic patients was higher than that of non-stenotic or unstudied patients. Urea clearance, corrected for recirc, rose with blood flow both in stenotic and non-stenotic patients. There were no differences in AP or in VP between stenotic and non-stenotic patients. At BFR ≥ 400 ml/min, a recirc threshold of 15% identified stenoses with sensitivity 100% and specificity 71%. We conclude (1) recirc increases with increasing BFR but not enough to outweight the concomitant increase in urea clearance; (2) significant access stenosis and recirc may be present even with low VP; (3) recirc was associated with arterial side stenoses; (4) at BFR ≥ 400 ml/min, access stenosis is associated with recirc > 15%.

The Detection of Blood Impurities Using Ultrasound Doppler

1980 ◽  
Vol 2 (4) ◽  
pp. 370-380 ◽  
Author(s):  
V. L. Newhouse ◽  
M. L. Hoover ◽  
S. R. Ash
Keyword(s):  
Blood Flow ◽  
Potential Importance ◽  
Velocity Of Sound ◽  
Particle Detection ◽  
Ultrasound Doppler ◽  
Carbon Particles ◽  
Extracorporeal Blood ◽  
Pulse Echo

The atraumatic detection of blood impurities such as charcoal particles has potential importance in the monitoring of extracorporeal blood flow for hemodialysis systems using carbon slurry in the dialisate and for blood detoxification using carbon columns. It is shown that existing clinical ultrasound Doppler systems can detect carbon particles whose diameter is comparable to that of an erythrocyte in concentrations as low as 1.5 times 10−6 g/ml in less than one second. It is shown that for particle detection in flow, Doppler systems are more sensitive than pulse echo systems of equivalent resolution by the ratio of the velocity of sound to that of the flow.

Regional Blood Acidification Enhances Extracorporeal Carbon Dioxide Removal

2014 ◽  
Vol 120 (2) ◽  
pp. 416-424 ◽  
Author(s):  
Alberto Zanella ◽  
Paolo Mangili ◽  
Sara Redaelli ◽  
Vittorio Scaravilli ◽  
Marco Giani ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Lactic Acid ◽  
Blood Flow Rate ◽  
Carbon Dioxide Removal ◽  
Low Flow ◽  
Extracorporeal Carbon Dioxide Removal ◽  
Membrane Lung ◽  
Extracorporeal Blood ◽  
Patients At Risk

Abstract Background: Extracorporeal carbon dioxide removal has been proposed to achieve protective ventilation in patients at risk for ventilator-induced lung injury. In an acute study, the authors previously described an extracorporeal carbon dioxide removal technique enhanced by regional extracorporeal blood acidification. The current study evaluates efficacy and feasibility of such technology applied for 48 h. Methods: Ten pigs were connected to a low-flow veno-venous extracorporeal circuit (blood flow rate, 0.25 l/min) including a membrane lung. Blood acidification was achieved in eight pigs by continuous infusion of 2.5 mEq/min of lactic acid at the membrane lung inlet. The acid infusion was interrupted for 1 h at the 24 and 48 h. Two control pigs did not receive acidification. At baseline and every 8 h thereafter, the authors measured blood lactate, gases, chemistry, and the amount of carbon dioxide removed by the membrane lung (VCO2ML). The authors also measured erythrocyte metabolites and selected cytokines. Histological and metalloproteinases analyses were performed on selected organs. Results: Blood acidification consistently increased VCO2ML by 62 to 78%, from 79 ± 13 to 128 ± 22 ml/min at baseline, from 60 ± 8 to 101 ± 16 ml/min at 24 h, and from 54 ± 6 to 96 ± 16 ml/min at 48 h. During regional acidification, arterial pH decreased slightly (average reduction, 0.04), whereas arterial lactate remained lower than 4 mEq/l. No sign of organ and erythrocyte damage was recorded. Conclusion: Infusion of lactic acid at the membrane lung inlet consistently increased VCO2ML providing a safe removal of carbon dioxide from only 250 ml/min extracorporeal blood flow in amounts equivalent to 50% production of an adult man.

scholarly journals Arterial line pressure control enhanced extracorporeal blood flow prescription in hemodialysis patients

2008 ◽  
Vol 9 (1) ◽  
Author(s):  
Franklin G Mora-Bravo ◽  
Alfonso Mariscal ◽  
Juan P Herrera–Felix ◽  
Salvador Magaña ◽  
Guadalupe De-La-Cruz ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pressure Control ◽  
Hemodialysis Patients ◽  
Arterial Line ◽  
Extracorporeal Blood ◽  
Line Pressure

scholarly journals Vascular Access Blood Flow Estimation Based On Standardized Extracorporeal Blood Flow in Hemodialysis Patients

2021 ◽  
Author(s):  
Franklin Geovany Mora-Bravo ◽  
Sonia Catalina Rivera González ◽  
Pamela Tatiana Morales Torres ◽  
Marco Rivera Ullauri
Keyword(s):  
Blood Flow ◽  
Observational Study ◽  
Upper Limb ◽  
Vascular Access ◽  
Hemodialysis Patients ◽  
Arterial Line ◽  
Flow Estimation ◽  
Extracorporeal Blood ◽  
Hemodialysis Unit ◽  
The Right

Abstract Background: Measurement of vascular access flow (Qa) is a recommendation in the care of hemodialysis patients. We developed an observational study to answer the following question: Can access blood flow be estimated?Methods: This observational study was carried out in the hemodialysis unit of the José Carrasco Arteaga Hospital in Cuenca-Ecuador. The sample calculation was 41 cases. Patients older than 17 years with stage 5d chronic renal failure and vascular access with arteriovenous fistula were included. The variables were descriptive of the population: Qa and extracorporeal blood flow (Qb). Qa measurement was performed with the Transonic ® monitor. Qb was measured at dynamic arterial line pressures (DALPs) of -60 mmHg, -100 mmHg, -160 mmHg, and -200 mmHg. The correlation coefficient "r" was obtained between Qa and Qb. SPSS 22.0 was used to analyze the information and perform a linear regression equation to estimate access blood flow (eQa).Results: Fifty-seven patients aged 62.9 ± 12.7 years with 29.4 ± 33 months on hemodialysis were included; 23 women (40.3%) and 45.6% had diabetic nephropathy. Fistulas were seen in 40 cases in the left upper limb (70.2%) and 17 (29.8%) in the right upper limb. The prevalence of aneurysms was 10.5%. The 50th percentile of Qb was 415 mL/min with a DALP of -200 mmHg. The mean access flow was 1516 ± 878 ml/min. The correlation between Qb and Qa was statistically more significant between Qb and DALP of -200 mmHg. The association had a coefficient Rs = 0.643 (IC 0.453 to 0.771) P <0.0001. The estimated access flow eQa = (Qb at DALP of -200 mmHg (mL/min) * 16.63) - 5449.71.Conclusions: It was possible to estimate access blood flow with parameters for easy intradialysis measurements. The equation obtained, if applied to the same patient with the same DALP, could become a useful parameter for monitoring vascular access.Trial registration: ClinicalTrials.gov Identifier: NCT00522704. Registered 14 March 2008, https://clinicaltrials.gov/ct2/show/NCT00522704

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