Thermodiffusion for Continuous Quantification of Hepatic Microcirculation—Validation and Potential in Liver Transplantation

Klar, E.; Kraus, Thomas; Bleyl, J. U.; Newman, W.H.; Bowman, H. F.; Hofmann, Walter; Kummer, Rüdiger von; Bredt, M.; Herfarth, Christian

doi:10.1006/mvre.1999.2166

Cited by 36 publications

(21 citation statements)

References 22 publications

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“…Previous methods, however, have been inefficient to measure local tissue perfusion (10,11). In this study, we used TDM to measure LMP distal to the LAD, which validated many other organs (11)(12)(13)(14).…”

Section: Discussionmentioning

confidence: 86%

Nicardipine Augments Local Myocardial Perfusion after Coronary Artery Reperfusion in Dogs

Jang

Kim

2003

J Korean Med Sci

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INTRODUCTIONThe measurement of perfusion is very important to understand the physiology at the tissue level. And local myocardial perfusion (LMP) can identify hypoperfused myocardial tissue more precisely. In particular, during ischemia the myocardial layers of the left ventricle can be ischemic, while the epicardial blood flow is preserved. Many drugs have been used to improve the myocardial function in patients with coronary disease, and they may affect the LMP by various mechanisms (1-5). Nicardipine, a dihydropyridine calcium antagonist, is one of the most commonly used drugs to control the high blood pressure after coronary artery bypass graft. Nicardipine has relatively selective coronary vascular action (6). However, there has been no study of identifying the nicaridipine effects in myocardium by using LMP after the coronary reperfusion.Therefore, this study was undertaken to evaluate the nicadipine's effect in myocardial layers after the coronary reperfusion. The LMP and left anterior descending coronary blood flow (BF-LAD) before and after left anterior descending coronary artery (LAD) occlusion were evaluated according to the nicardipine administration. MATERIALS AND METHODSThis investigations were performed under a protocol approved by the Institutional Animal Investigation Committee, Keimyung University, Daegu, Korea. A total of 14 mongrel dogs, weighing 20-25 kg, were entered into the study. We divided the dogs into two groups, control group (n=7) and nicardipine group (n=7). The anesthesia was induced by 20 mg/kg thiopental sodium and 0.2 mg/kg vecuronium bromide followed by tracheal intubation after 2 min. Mechanical ventilation was done with 50% nitrous oxide in oxygen and 1-1.5 vol% isoflurane with a tidal volume of 15 mL/kg with a respiratory rate of 12/min.A left thoracotomy was performed on the 5th or 6th intercostal space and LAD was exposed for occlusion and release. A thermal diffusion microprobe (TDM) was implanted in the myocardium perfused by the exposed LAD. To prevent the TDM displacement during cardiac contraction, the TDM was sutured in place. The TDM was then connected to QFlow J Korean Med Sci 2003; 18: 23-6 ISSN 1011-8934 Copyright � The Korean Academy of Medical Sciences 23 Nicardipine Augments Local Myocardial Perfusion after Coronary Artery Reperfusion in DogsNicardipine is a potent coronary and systemic vasodilator without depression of ventricular function. We investigated the changes in local myocardial perfusion (LMP) according to the nicardipine administration after coronary reperfusion in a beating canine model. A Doppler probe was placed around the left anterior descending coronary artery (LAD) and thermal diffusion microprobe was implanted in the myocardium perfused by the exposed LAD. To define the nicardipine effects, we compared the two groups (control group, n=7 vs nicardipine group, n=7). In nicardipine group, 5 g/kg/min nicardipine was infused continuously. After the release of the LAD occlusion, LAD blood flow were increased compared to the baseline of both...

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Section: Discussionmentioning

confidence: 86%

Nicardipine Augments Local Myocardial Perfusion after Coronary Artery Reperfusion in Dogs

Jang

Kim

2003

J Korean Med Sci

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“…These probes have been used in multiple microvascular applications ranging from cerebral blood flow [4] to pedicle flaps [5]. They also showed success in ex vivo hepatic perfusion monitoring [7,8]. However, although very suitable to measure tissue perfusion, the principle of thermal diffusion is difficult to apply directly on blood vessels.…”

Section: Introductionmentioning

confidence: 99%

Optimizing probe design for an implantable perfusion and oxygenation sensor

Akl

Long

McShane

et al. 2011

Biomed. Opt. Express

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Abstract:In an effort to develop an implantable optical perfusion and oxygenation sensor, based on multiwavelength reflectance pulse oximetry, we investigate the effect of source-detector separation and other sourcedetector characteristics to optimize the sensor's signal to background ratio using Monte Carlo (MC) based simulations and in vitro phantom studies. Separations in the range 0.45 to 1.25 mm were found to be optimal in the case of a point source. The numerical aperture (NA) of the source had no effect on the collected signal while the widening of the source spatial profile caused a shift in the optimal source-detector separation. Specifically, for a 4.5 mm flat beam and a 2.4 mm × 2.5 mm photodetector, the optimal performance was found to be when the source and detector are adjacent to each other. These modeling results were confirmed by data collected from in vitro experiments on a liver phantom perfused with dye solutions mimicking the absorption properties of hemoglobin for different oxygenation states. Frank, "Development of an implantable oximetry-based organ perfusion sensor," Conf. Proc. IEEE Eng. Med.

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“…Therefore, it is difficult to compare with precision the effects of the two different types of blood flows upon peripheral tissue perfusion, and thus it is difficult to prove that pulsatile blood flow is superior in extracorporeal circulation systems. However, recently the thermal diffusion technique has offered the possibility of obtaining real time, continuous, absolute values of peripheral tissue perfusion and allowing peripheral perfusion measurements in organs such as the brain, 7 liver, 8 and kidney. 9 Consequently, our study was designed to directly prove that pulsatile blood flow is superior to nonpulsatile blood flow with respect to peripheral tissue perfusion in the case of extracorporeal circulation.…”

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confidence: 99%

The Effects of Pulsatile Flow Upon Renal Tissue Perfusion During Cardiopulmonary Bypass: A Comparative Study of Pulsatile and Nonpulsatile Flow

Kim¹,

Son²,

Yao³

et al. 2005

ASAIO Journal

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This study was conducted to directly compare the effects of pulsatile and nonpulsatile blood flow in the extracorporeal circulation upon renal tissue perfusion by using a tissue perfusion measurement system. A total cardiopulmonary bypass circuit was constructed to accommodate twelve Yorkshire swine, weighing 20 approximately 30 kg. Animals were randomly assigned to group 1 (n = 6, nonpulsatile centrifugal pump) or group 2 (n = 6, pulsatile T-PLS pump). A tissue perfusion measurement probe (Q-Flow 500) was inserted into the renal parenchymal tissue, and the extracorporeal circulation was maintained for an hour at a pump flow rate of 2 L/min after aortic cross-clamping. Tissue perfusion flow in the kidney was measured before bypass and every 10 minutes after bypass. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout bypass (ranging 48.5-64.1 ml/min/100 g in group 1 vs. 51.0-88.1 ml/min/100 g in group 2). The intergroup difference was significant at 30 minutes (47.5 +/- 18.3 ml/min/100 g in group 1 vs. 83.4 +/- 28.5 ml/min/100 g in group 2; p = 0.026). Pulsatile flow achieves higher levels of tissue perfusion of the kidney during short-term extracorporeal circulation. A further study is required to observe the effects of pulsatile flow upon other vital organs and its long-term significance.

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Thermodiffusion for Continuous Quantification of Hepatic Microcirculation—Validation and Potential in Liver Transplantation

Cited by 36 publications

References 22 publications

Nicardipine Augments Local Myocardial Perfusion after Coronary Artery Reperfusion in Dogs

Nicardipine Augments Local Myocardial Perfusion after Coronary Artery Reperfusion in Dogs

Optimizing probe design for an implantable perfusion and oxygenation sensor

The Effects of Pulsatile Flow Upon Renal Tissue Perfusion During Cardiopulmonary Bypass: A Comparative Study of Pulsatile and Nonpulsatile Flow

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