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Background: ModulHeart (Puzzle Medical Devices Inc) is a novel percutaneous flow entrainment pump anchored in the descending aorta. The current study evaluates the hemodynamic effect of ModulHeart support and its impact on cerebral, myocardial, and renal blood flow. Methods: ModulHeart was implanted in the descending aorta of four healthy calves. A ramp protocol (2000 RPM increments) was performed with the pump operating at five different speeds from 14 000 to 22 000 RPM. For each speed, pressures proximal and distal to the pump, and right heart catheterization measurements were recorded. Stable‐isotope labeled microspheres were injected in the left ventricle to evaluate organ perfusion. Results: Thermodilution cardiac output increased by 23% at 22 000 RPM. Greater pump speeds resulted in greater pump gradients, up to 10 mm Hg in mean arterial pressure at 22 000 RPM, without significant reduction of proximal perfusion pressures. Arterial pulse pressure remained stable at all speeds. ModulHeart was not associated with a reduction in cerebral or myocardial blood flow at any speed. Renal cortical and medullary blood flow increased by up to 50% and 40%, respectively. Conclusion: The ModulHeart device implanted in the descending aorta of healthy calves resulted in significant arterial pressure gradients and preserved pulse pressure. Greater pump speeds translated into greater increases in renal blood flow, with no decrease in cerebral or myocardial perfusion. [ABSTRACT FROM AUTHOR]

To alleviate the persistent shortage of donor livers, high‐risk liver grafts are increasingly being considered for liver transplantation. Conventional preservation with static cold storage falls short in protecting these high‐risk livers from ischemia–reperfusion injury, as evident from higher rates of post‐transplant complications such as early allograft dysfunction and ischemic cholangiopathy. Moreover, static cold storage does not allow for a functional assessment of the liver prior to transplantation. To overcome these limitations, dynamic strategies of liver preservation have been proposed, designed to provide a protective effect while allowing pre‐transplant functional assessment. In this review, we discuss how different dynamic preservation strategies exert their effects, where we stand in assessing liver function and what challenges are lying ahead. [ABSTRACT FROM AUTHOR]

Raman spectroscopy was applied in this research to monitor the overall health and degradation of porcine livers perfused ex vivo using the VasoWaveW® perfusion system. A novel Raman-based diagnostic analysis was developed that enables near real-time and label-free monitoring of organ health during ex vivo perfusion designed to extend the useful life of the organ for transplantation. Multivariate statistical analysis of Raman spectra of organ perfusate fluid, using a combination of principal component analysis and linear discriminant analysis, proved to be an effective technique to assess the degradation properties of the livers. Three livers (with replicates) were perfused ex vivo under different pressures and temperatures and were compared with a 24-h time-course. Results indicated that perfusion pressure was a more significant factor in organ degradation than was temperature. In addition, a non-linear degradation profile was identified for all three perfused livers, and this profile was different for individual livers, demonstrating the time-dependent transition from its initial 'healthy' state towards a more 'unhealthy' degenerative state at 24 h. The Raman spectroscopy-based approach described here has potential applications in perfusion and diagnostic instrumentation that can be used in near real-time during organ transit and in operating rooms to help identify appropriately healthy organs for transplantation. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

1. Poor perfusion of the kidneys and gut, and associated functional impairment, are major problems in the first days of life in very preterm infants. These complications can be associated with a substantial mortality and further problems such as reduced kidney growth and chronic renal problems in later childhood. 2. There is very little information, and consequently considerable debate, about how or even whether to improve perfusion of the vital organs of this most vulnerable group of babies. Current treatments simply do not consistently improve babies’ perfusion generally or kidney and gut perfusion and function in particular. 3. In this review we critically examine clinical and experimental evidence that suggests that exposure to low oxygen levels before and during birth may be a significant contributor to impaired systemic perfusion, and highlight areas requiring further research. 4. This knowledge is essential to develop and refine ways of improving perfusion of the kidneys and other vital organs in premature babies. [ABSTRACT FROM AUTHOR]

Mean arterial pressure (MAP) has been characterized as a more sensitive and physiologically appropriate hemodynamic parameter in the detection of hemapheresis-related hypotension, resulting in a much closer correlation with the presence of symptomatic hypotension. Patients were enrolled over a 12-month period and data collected on any previous diagnosis of hypertension, antihypertensive therapy used, indication for apheresis, age decile, and gender. Baseline vital signs, any hypotensive signs or symptoms observed, and the patient's vital signs at the time of any hypotensive episode were recorded. Patients were assigned to a subgroup, sensitivity and specificity analysis performed, positive likelihood ratios calculated, receiver operating characteristic curves constructed, and ideal cutoff values identified. The incidence of hypotension among our study population was found to be 6.8%. Over all procedures, systolic blood pressure (SBP) was determined to be a 'poor' test for detecting hypotension, while MAP demonstrated a 'fair' capacity. A downward normalization was evident in the ideal cutoff value based upon a patient's hypertensive history. The currently accepted SBP less than 80 mmHg cutoff failed to detect hypotensive episodes among baseline hypertensive patients, raising questions about its sensitivity. Based upon physiologic principles and study findings, a MAP-based criterion is preferable in the diagnosis of hypotension during hemapheresis. J. Clin. Apheresis © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Baicu SC, Simmons PM, Campbell LH, Taylor MJ, Brockbank KGM. Interstitial fluid analysis for assessment of organ function. Clin Transplant 2004: 18 (Suppl. 12): 16–21. © Blackwell Munksgaard, 2004 Evaluation methods are required for non-heart-beating donor (NHBD) kidneys to ensure the success of transplantation. In this study, the microdialysis technique was employed for the ex-vivo assessment of hypothermically preserved NHBD kidney function. Microdialysis probes were placed in the renal cortex of 2 h warm ischaemic porcine kidneys to monitor interstitial pyruvate dynamics during hypothermic machine perfusion with perfusate containing 29.4 mM fructose-1,6-diphosphate (FDP). The presence of exogenous FDP in the perfusate induced no changes in the renal flow rate and vascular resistance, renal artery effluent biochemistry, or pyruvate concentration relative to untreated control kidneys. Significant increases in pyruvate production ( P < 0.05), however, were observed after 12 h of perfusion in the interstitial fluid of FDP-treated kidneys relative to control kidneys. After 24 h of perfusion, interstitial fluid concentrations of pyruvate were 149.1 ± 58.4 vs. 55.6 ± 17.9 µM ( P < 0.05) in the FDP and control group, respectively. The microdialysis probe collected the interstitial fluid directly from the cellular sites of metabolic and synthetic activity, where perfusate dilution was minimal. Consequently, the biochemical changes induced by the organ metabolic activity were detected only at the interstitial level, in the microdialysates. Interstitial fluid pyruvate may be a good indicator of kidney function. The addition of FDP to the perfusion solution during ischaemic kidney preservation resulted in enhanced pyruvate production in the extracellular space, indirectly reflecting an increase in anaerobic ATP production. The pyruvate will be transformed during organ reperfusion into acetyl Co-A enzyme allowing an immediate start of aerobic metabolism. This in turn can increase the amount of ATP available to the cells and may help prevent reperfusion injury upon transplantation. [ABSTRACT FROM AUTHOR]

Abstract: Research of the distributed artificial heart is important not only to acquire the means of individual organ perfusion but also to clarify the characteristics of the organ and the mechanism of blood distribution. To investigate the distributed artificial heart, the miniature undulation pump was developed. The outer diameter and the thickness of the developed pump were 38 mm and 11 mm, respectively. The priming volume of the pump was 3.2 ml. The total size including the motor unit was 38 mm in diameter and 32 mm in length. The total weight was 67.5 g. The total volume was 27.5 ml. The pump was driven with pulse width modulation by using a 1 chip motor controller. More than 5 L/min of continuous output could be obtained. The results showed that the developed miniature undulation pump system had enough performance for individual organ perfusion. [ABSTRACT FROM AUTHOR]