The Use of Regional Anesthesia to Reduce Blood Loss in Isolated Limb Perfusion (ILP)-A Novel Approach.

BACKGROUND: Isolated limb perfusion (ILP) for soft tissue sarcomas (STS) is usually performed with tumor necrosis factor alpha (TNF-α) and melphalan. ILP regularly leads to a total blood loss (BLt) of 1.5-2 L/patient. Blood inflow from the central blood circulation to the limb is influenced by unstable pressure gradients and pain reactions after the administration of melphalan. With perioperative regional anesthesia (RA), pain levels can be reduced, and the pressure gradient stabilized resulting in a reduced BLt. The aim of this study was to compare the BLt with and without RA in patients with ILP during circulation of drugs. METHODS: Patients were treated according to the following protocol: After the establishment of limb circulation, ILP was started with the administration of TNF-α. Half the dose of melphalan was given as a bolus after 30 min, and the remaining dose was continuously administered in the following 30 min. The extremity was washed out after 90 min. ILP with perioperative RA (supraclavicular plexus block/peridural catheter) was performed prospectively in 17 patients and compared to a matched retrospective control group of 17 patients without RA. BLt was documented and perioperative anesthesiological data were analyzed for response rates after the application of melphalan (RaM). RESULTS: BLt and RaM tended to be lower for the intervention group with RA if compared to the control group without RA in all analyses. The trend of lower BLt and RaM in ILP with RA was more pronounced for the upper extremity compared to the lower extremity. Results were not statistically significant. CONCLUSION: These findings indicate that the use of RA can help to stabilize hemodynamic anesthetic management and reduce the BLt in ILP, especially during perfusion of the upper extremities.

[Color Doppler Sonography: Device Settings Determine the Quality of Diagnosis and the Occurrence of Artifacts]. / Farbdopplersonografie: Geräteeinstellungen bedingen die Diagnosequalität und das Auftreten von Artefakten.

Color Doppler Sonography: Device Settings Determine the Quality of Diagnosis and the Occurrence of Artifacts Abstract. The major goal of the ultrasound examination is to find the right diagnosis. The correct setting of the device parameters is crucial for a reliable diagnosis. The examiner's knowledge of possible artifacts is helpful in evaluating the ultrasound images. Artifacts are not only present in B-mode sonography, but also in color Doppler sonography. Terms such as blooming, aliasing and twinkling refer to classic artifacts in color Doppler sonography. The causes of these artifacts and the possibilities of influencing them by device technology are presented and discussed. Exemplary images document the most important artifacts in color Doppler sonography.

Does standoff material affect acoustic radiation force impulse elastography? A preclinical study of a modified elastography phantom.

PURPOSE: This study was conducted to determine the influence of standoff material on acoustic radiation force impulse (ARFI) measurements in an elasticity phantom by using two different probes. METHODS: Using ARFI elastography, 10 observers measured the shear wave velocity (SWV, m/sec) in different lesions of an elasticity phantom with a convex 4C1 probe and a linear 9L4 probe. The experimental setup was expanded by the use of an interposed piece of porcine muscle as standoff material. The probe pressure on the phantom was registered. RESULTS: Faulty ARFI measurements occurred more often when quantifying the hardest lesion (74.0 kPa 4.97 m/sec) by the 9L4 probe with the porcine muscle as a standoff material interposed between the probe and the phantom. The success rate for ARFI measurements in these series was 52.4%, compared with 99.5% in the other series. The SWV values measured with the 9L4 probe were significantly higher (3.33±1.39 m/sec vs. 2.60±0.74 m/sec, P<0.001 in the group without muscle) and were closer to the reference value than those measured with the 4C1 probe (0.25±0.23 m/sec vs. 0.85±1.21 m/sec, P<0.001 in the same group). The SWV values measured when using the muscle as a standoff material were lower than those without the muscle (significant for 9L4, P=0.040). The deviation from the reference value and the variance increased significantly with the 9L4 probe if the muscle was in situ (B=0.27, P=0.004 and B=0.32, P<0.001). In our study, the pressure exerted by the operator had no effect on the SWV values. CONCLUSION: The presence of porcine muscle acting as a standoff material influenced the occurrence of failed measurements as well as the variance and the accuracy of the measured values. The linear high-frequency probe was particularly affected.

Preclinical evaluation of acoustic radiation force impulse measurements in regions of heterogeneous elasticity.

PURPOSE: The purpose of this study was to compare the reliability of ultrasound-based shear wave elastography in regions of homogeneous versus heterogeneous elasticity by using two different probes. METHODS: Using acoustic radiation force impulse (ARFI) elastography, we measured the shear wave velocity (SWV) in different lesions of an elastography phantom with the convex 4C1 probe and the linear 9L4 probe. The region of interest (ROI) was positioned in such a way that it was partly filled by one of the lesions (0%, 25%, 50%, 75%, and 100%) and partly by the background of the phantom (100%, 75%, 50%, 25%, and 0%, respectively). RESULTS: The success rate was 98.5%. The measured value and the reference value of SWV correlated significantly (r=0.89, P<0.001). Further, a comparison of the two probes revealed that there was no statistical difference in either the mean or the variance values. However, the deviation of SWV from the reference was higher in the case of the 9L4 probe than in the case of the 4C1 probe, both overall and in measurements in which the ROI contained structures of different elasticity (P=0.021 and P=0.002). Taking into account all data, for both probes, we found that there was a greater spread and deviation of the SWV from the reference value when the ROI was positioned in structures having different elastic properties (standard deviation, 0.02±0.01 m/sec vs. 0.04±0.04 m/sec; P=0.010; deviation from the reference value, 0.21±0.12 m/sec vs. 0.38±0.27 m/sec; P=0.050). CONCLUSION: Quantitative ARFI elastography was achievable in structures of different elasticity; however, the validity and the reliability of the SWV measurements decreased in comparison to those of the measurements performed in structures of homogeneous elasticity. Therefore, a convex probe is preferred for examining heterogeneous structures.

Evaluation of Hemodynamic Determinants of Quantitative Tissue Doppler Echocardiography in the Assessment of Left Ventricular Function.

The aim of the present study was to determine whether quantitative tissue Doppler echocardiography has a role in the assessment of left ventricular hemodynamics. Thirty patients with suspected or known heart disease, but no wall motion abnormalities, took part in the study. Quantitative tissue Doppler echocardiography was performed using new software for digital analysis of the tissue Doppler signal. Average systolic subendocardial (S1), subepicardial (S2), and transmural (S3) wall velocity data were obtained from the inferoposterior wall and compared with the hemodynamics, including high fidelity pressure readings. S1 and S3 rates were found to be most reliable, being directly related to the peak rate of left ventricular pressure rise (dP/dt(peak)) and inversely to systemic vascular resistance (SVR) and resistance index (SVRI). The best correlation was between S1, dP/dt(peak), and SVRI (multiple regression analysis: r = 0.76, P < 0.0001; simple regression analysis relating S1 to dP/dt(peak)/SVRI: r = 0.77, SEE = 0.25, P < 0.0001). Thus, wall velocity indices as defined in this study have promise to become helpful in guiding the therapeutic modulation of inotropy and afterload in patients with heart failure.