Bedside monitoring of circulating blood volume has become possible with the introduction of an integrated fiberoptic monitoring system that calculates blood volume from the changes in blood ...concentration of indocyanine green dye 4 mins after injection. The aim of this investigation was to compare the blood volume estimate of the integrated fiberoptic monitoring system (group 1) with the standard methods of blood volume measurement using Evans blue (group 2), and indocyanine green measured photometrically (group 3).
Prospective laboratory study.
Animal laboratory of a University's institute for experimental surgery.
Eleven anesthetized, paralyzed, and mechanically ventilated piglets.
A central venous catheter was used for the injection of the indicator dyes (Evans blue and indocyanine green). A fiberoptic thermistor catheter was advanced into the thoracic aorta. The fiberoptic catheter detects indocyanine green by reflection densitometry for the estimation of blood volume of the integrated fiberoptic monitoring system. Samples for the determination of Evans blue and indocyanine green concentrations were drawn from an arterial catheter in the femoral artery over a period of 17 mins after injection.
Measurements were performed during normovolemia, hypovolemia (blood withdrawal of < or = 30 mL/kg), and hypervolemia (retransfusion of the withdrawn blood plus an infusion of 10% hydroxyethyl starch 45 mL/kg). Linear regression, correlation, and bias were calculated for the comparison of the blood volume estimates by the fiberoptic monitoring system (group 1) vs. the total blood volume estimates using Evans blue (group 2) and indocyanine green (group 3): group 1 = 0.82.group 2-26 mL; r2 = 82.71%; r = .91; n = 40; group 1-group 2 +/- 1 SD = -435 +/- 368 mL; group 1 = 0.79.group 3 + 50 mL; r2 = 74.81%; r = .87; n = 28; group 1-group 3 +/- 1 SD = -506 +/- 374 mL.
The results demonstrate that the blood volume estimate of the fiberoptic monitoring system (group 1) correlates closely with the total blood volume measurement using Evans blue (group 2) and indocyanine green (group 3). Trapped indicator in the packed red cell column after centrifugation of the blood samples may account for an overestimation of group 2 and group 3 of approximately 10% to 14%, but there still remains a proportional difference of 10% between group 1 vs. group 2 and vs. group 3. This difference is due to the longer mixing times of group 3 (16 mins) and group 2 (17 mins), during which they are distributed in slowly exchanging blood pools. It seems that the blood volume estimate of the fiberoptic monitoring system (group 1) represents the actively circulating blood volume and may be useful for bedside monitoring.
Abdominoplasty procedures involve a high risk of early complications, including hematomas, seromas, necrosis, and wound-healing problems. Their rationale is evident from the vascular anatomy of the ...abdominal wall, as traditional abdominoplasty includes a division of the main perforating vessels. No studies exist to quantitatively assess the consequences of abdominoplasty on the perfusion of the random pattern abdominal flap. To address this issue and quantify the influence of classic abdominoplasty on the perfusion of the abdominal skin, the authors performed a prospective clinical trial including 15 low-risk patients undergoing abdominoplasty for aesthetic purposes. Perfusion of the abdominal flap was measured intraoperatively using the technique of dynamic laser-fluorescence-videoangiography. In the region between the umbilicus and the transverse scar (zone 1), the increment of fluorescence (the slope of the intensity curve during inflow of the indocyanine green) was recorded and compared with the intensity curve of normal tissue that was not involved in surgery (thoracic wall). The results of the intraoperative indocyanine green perfusography showed a significant impairment of the vascular supply of zone 1 in all patients. The mean perfusion index in this region was 17.2 percent (range, 5 to 32 percent) of the perfusion of the surrounding skin that was not involved in surgery. The complication rate was 33 percent (five patients) and included two cases of hematoma and three cases of scar dehiscence with skin and/or fat necrosis. These data indicate that conventional abdominoplasty including extended undermining and division of the superficial and the deep arterial systems causes profound devascularization of the abdominal flap. This might explain the high incidence of complications following this procedure.
This paper presents a methodology for compact model evaluation and validation at circuit level for RF and mm-wave applications. Accurate compact models are a prerequisite for efficient circuit design ...but currently modeling engineers lack of suitable verification procedures. In this work we detail a methodology to fulfill these requirements together with circuit examples, starting from the simplest differential pair to the most advanced four stage differential LNA working at 220GHz. It is shown that a complete hierarchy of validation circuits (from the simplest circuit to the most complex) provides a new perspective with respect to the crucial task of model qualification but also directions for future compact model developments.
We review the development of wavelength stabilized 980nm pump laser modules without active temperature stabilization for applications in erbium-doped fiber amplifiers. Operation over a wide ...temperature range with an output power exceeding 400mW at an ambient temperature of 70°C is demonstrated. The overall reliability of uncooled modules is estimated to be well below 500 FIT at all operating conditions. Such devices are made possible by continuous development and steady improvement of the pump laser chip, the optimization of the fiber Bragg grating stabilization scheme, careful design of the module package, and extended reliability analysis on the basis of stress tests as well as field data.
A person’s cultural background as well as their gaze direction have been identified as relevant factors that influence the behavioural and neural processing of emotional expressions. However, ...research on their combined influence is sparse. Here, we manipulated the cultural background and gaze direction of emotion-encoders to investigate the interaction of both factors during the neural processing of emotions. Stimuli consisted of short video sequences showing faces that displayed either direct or averted gaze, expressed either anger or happiness, and represented either cultural in-group (European faces) or cultural out-group members (Asian faces). While undergoing functional magnetic resonance imaging, a group of German participants rated the stimuli with respect to their valence. Results revealed that when anger was expressed with direct gaze, more activation was found in the dorsomedial and dorsolateral prefrontal cortices in response to cultural out-group compared to in-group members. However, when anger was expressed with averted gaze, activity increased in the amygdala and the striatum in response to cultural in-group compared to out-group members. With respect to happiness, enhanced neural activation in medial and lateral prefrontal cortical areas was associated with the processing of cultural in-group compared to out-group members expressing happiness with direct gaze. These findings indicate a complex interplay between culture, gaze direction and the valence of emotions.
Purpose:
Central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP) and right ventricular end-diastolic volume (RVEDV) are often regarded as indicators of both circulating blood volume ...and cardiac preload. To evaluate these relationships, the response of each variable to induced volume shifts was tested. The relationships between these variables and cardiac index (CI) and stroke volume index (SVI) was also recorded to assess the utility of each variable as an indicator of cardiac preload. The responses of the new variable intrathoracic blood volume (ITBV) to the same maneuvers was also tested. To examine the effects of changes in cardiac output alone on ITBV, the effects of infusing dobutamine were studied.
Materials and Methods:
Ten anesthetized piglets were studied during conditions of normovolemia, hypovolemia, and hypervolemia. The effects of an infusion of dobutamine were examined under normovolemia and hypovolemia. Cardiac output was measured by thermodilution, and ITBV was measured by double-indicator dilution.
Results:
CI was correlated to CVP with
r
2 = .42 (
P ≤ .01), to PAOP with
r
2 = .43 (
P ≤ 5.01), to RVEDV index with
r
2 = .21 (
P ≤ .01), and to ITBV with
r
2 = .78 (
P ≤ .01) (pooled absolute values). Bias (mean difference of the percent changes with normovolemia = 100%) ± 1 SD; for SVI - ITBV index was 1 ± 22%, for SVI — CVP it was −128 ± 214%; for SVI — PAOP it was −36 ± 46%; and for SVI -RVEDV index it was 1 ± 29%. Dobutamine infusion increased heart rate (to about 190 × min
−1) and CI by 30% in normovolemia and hypovolemia, while ITBV remained basically unchanged.
Conclusions:
Under the experimental conditions choosen neither CVP, PAOP, nor RVEDV reliably indicated changes in circulating blood volume, nor were they linearly and tightly correlated to the resulting changes in SVI. ITBV reflected both changes in volume status and the resulting alteration in cardiac output. The possibility that ITBV might be cardiac output-dependent was not supported. ITBV, therefore, shows potential as a clinically useful indicator of overall cardiac preload.
Continuous emergence of known or new pathogens as well as increasing complexity of pathogen testing challenge the provision of safe blood products. Pathogen inactivation using amotosalen + UVA ...effectively reduces a number of different pathogens including viruses, bacteria and parasites (Transfusion 2006; 46:1168).
We determined the impact of pathogen inactivation on the coagulation activity of frozen plasma (FP) using amotosalen (150μM) and UVA (3 J/cm2) in the operational setting of a large blood bank. Plasma (650mL) was collected as single-donor apheresis plasma processed within 8h (arm A) and whole blood derived plasma pooled from three different, but ABO and Rh identical donors after an initial storage time of 8h (arm B) or after 22h (arm C) before photochemical treatment (PCT). Each 650mL unit of treated plasma was divided into 3 units of 200mL each prior to freezing at −40°C. Eight subsequent FP units (200mL) from individual collections were analyzed per arm, representing different blood groups. Samples for coagulation analysis were taken at baseline, after PCT and absorption of amotosalen (post-inactivation), and after six weeks of storage at −40°C (post-storage). Global coagulation tests (PT, aPTT), thrombin time, fibrinogen activity (Clauss) and fibrinogen antigen levels remained within normal ranges at all time points in all three arms. Similarly, activities of coagulation factors II, V, VII, IX, X, XI, XII, XIII, as well as von Willebrand factor (vWF) antigen, ristocetin cofactor, vWF-collagen binding capacity, antithrombin, protein C levels, protein S activity, plasmin-antiplasmin-complexes (PAP), plasminogen levels, and D-dimers did not show significant alterations. Median factor VIII activities were diminished compared to baseline (= 100%) in all three groups post-inactivation and post-storage, respectively (A: 84% and 80%; B: 74% and 65%; C: 84% and 93%). Significant differences in thrombin-antithrombin-complex (TAT) levels were seen between apheresis plasma (< 0.1 ng/ml) and plasma processed from whole blood after 8h (7.25 ng/ml) and 22h (57 ng/ml) of storage time prior to PCT. During pathogen inactivation, there was no increase in TAT levels ruling out that thrombin was formed through the inactivation process.
In summary, pathogen inactivation of FP using amotosalen + UVA does not significantly influence coagulation parameters with the exception of FVIII. The decrease in FVIII activity might be explained in part by an additional freeze-thawing cycle included in the protocol due to technical reasons. Increased TAT levels, especially in arm C, were not reflected in decreased AT activity or an increase in other markers of coagulation activation, but indicate continuous, although moderate activation of the coagulation cascade during storage time.
We conclude that the described inactivation procedure for whole blood derived and apheresis FP can be performed in a large blood bank setting without significant decreases in coagulation factor activities and thus without major impairment of the functional capacity of therapeutic plasma.
This paper presents the experimental results of \(17~MeV\) proton irradiation on a \(60~GHz\) low power, half-duplex transceiver (TRX) chip implemented in \(65~nm\) CMOS technology. It supports short ...range point-to-point data rate up to \(6~Gbps\) by employing on-off keying (OOK). To investigate the irradiation hardness for high energy physics applications, two TRX chips were irradiated with total ionizing doses (TID) of \(74~kGy\) and \(42~kGy\) and fluence of \(1.4~\times\)10\(^{14}~ N_{eq}/cm^2\) and \(0.8~\times\)10\(^{14}~N_{eq}/cm^2\) for RX and TX modes, respectively. The chips were characterized by pre- and post-irradiation analogue voltage measurements on different circuit blocks as well as through the analysis of wireless transmission parameters like bit error rate (BER), eye diagram, jitter etc. Post-irradiation measurements have shown certain reduction in performance but both TRX chips have been found operational through over the air measurements at \(5~Gbps\). Moreover, very small shift in the carrier frequency was observed after the irradiation.
Provider: - Institution: - Data provided by Europeana Collections- Köln, Universität zu Köln, Diss., 2013- All metadata published by Europeana are available free of restriction under the Creative ...Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
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