Explore the vast range of titles available.

Abstract The use of pulmonary artery catheters has diminished, so that other technologies are emerging. Central venous oxygen saturation measurement (ScvO2) as a surrogate for mixed venous oxygen saturation measurement (Sv−O2) is simple and clinically accessible. To maximize the clinical utility of ScvO2 (or Sv−O2) measurement, it is useful to review what the measurement means in a physiologic context, how the measurement is made, important limitations, and how this measurement may be helpful in common clinical scenarios. Compared with cardiac output measurement, Sv−O2 is more directly related to tissue oxygenation. Furthermore, when tissue oxygenation is a clinical concern, Sv−O2 is less prone to error compared with cardiac output, where small measurement errors may lead to larger errors in interpreting adequacy of oxygen delivery. ScvO2 should be measured from the tip of a central venous catheter placed close to, or within, the right atrium to reduce measurement error. Correct clinical interpretation of Sv−O2, or its properly measured ScvO2 surrogate, can be used to (1) estimate cardiac output using the Fick equation, (2) better understand whether a patient's oxygen delivery is adequate to meet their oxygen demands, (3) help guide clinical practice, particularly when resuscitating patients using validated early goal directed therapy treatment protocols, (4) understand and treat arterial hypoxemia, and (5) rapidly estimate shunt fraction (venous admixture).

To evaluate the feasibility of streamlined radioembolization using yttrium-90 resin microspheres without lung shunt fraction (LSF) assessment in patients with intrahepatic cholangiocarcinoma (ICC). This single-center retrospective study included 23 patients with ICC who underwent radioembolization using resin microspheres (SIR-Spheres; SIRTEX, Woburn, MA, USA) without LSF measurement between April 2022 and April 2025. Eligibility criteria, based on prior institutional data, included a target tumor size less than 10 cm, absence of hepatic vein invasion and intratumoral dysmorphic vessels, and an institutional waiting time exceeding one week for macroaggregated albumin scintigraphy. All patients had at least one follow-up imaging study. Radiation activity was prescribed according to tumor location, liver function, and clinical setting, using both single-compartment and multi-compartment dosimetry under the assumptions of a 5% LSF and a tumor-to-normal (TN) ratio of 3. Post-treatment yttrium-90 PET/CT dosimetry was performed in 12 patients. Treatment-related toxicity, tumor response, and local tumor progression-free survival were analyzed. The median administered activity was 1.43 GBq (interquartile range, 0.89-2.15). The median mean absorbed dose to the perfused tissue was 147 Gy, and the median tumor absorbed dose (TAD) was 339 Gy, assuming a TN ratio of 3. Post-treatment PET/CT analysis demonstrated a median TAD of 371 Gy and a median TN ratio of 4.7. No patient developed symptomatic radiation pneumonitis. Best tumor response was partial response in 52% of patients and stable disease in 48%. Local tumor progression-free survival rates at six months, one year, and two years were 95.2%, 81.1%, and 81.1%, respectively. Streamlined radioembolization without LSF assessment appears feasible and may represent a practical alternative to conventional multi-step workflows in patients with ICC measuring less than 10 cm.

BackgroundTechnetium-99m macroaggregated albumin is used to estimate lung shunt fraction (LSF) prior to yttrium-90 (Y90). Studies have debated the safety and efficacy of Y90 in patients with LSF > 15%. We aimed to assess the role of Y90 in hepatocellular carcinoma (HCC) with LSF > 15%.MethodsWith IRB approval, we searched our prospectively acquired database of HCC patients with Y90 treated with LSF > 15%. Median LSF and liver and lung doses were calculated. The response was assessed using RECIST. Overall survival (OS) was calculated from date of first Y90.ResultsA total of 103 HCC patients underwent Y90. The median baseline LSF was 24.4% (IQR 18.1–28.8). Patients exhibited multifocal disease (59/103, 60%) and median tumor size of 7.85 cm (IQR 5.2, 10.57). BCLC class was A, B, C, and D in 7 (7%), 5 (5%), 85 (83%), and 6 (6%) patients, respectively. The median liver dose was 84.6 Gy (IQR 57.4, 107.55). The median lung dose per session and cumulatively was 22.9 Gy (IQR 15–28) and 29.5 Gy (IQR 20.5–44.3). Thirty-three patients (32%) demonstrated partial response, 57 stable disease, and 13 (13%) had progressive disease. The median OS was 7.3 months (95% CI 5.3, 11.47). Twenty patients (19%) had non-specific pulmonary symptoms (cough, shortness of breath, wheezing) in the 1-year post-Y90. The median time to the appearance of non-specific pulmonary symptoms was 63 days (range 7–224). Thoracic imaging demonstrated no pulmonary fibrosis/injury following treatment in any patient.ConclusionY90 can be performed in patients with LSF > 15%. The RECIST response was identified in 32% of the patients. In isolation, LSF > 15% should not deter from treatment with Y90.

Background Prone position is used in acute respiratory distress syndrome and in coronavirus disease 2019 (Covid-19) acute respiratory distress syndrome (ARDS). However, physiological mechanisms remain unclear. The aim of this study was to determine whether improved oxygenation was related to pulmonary shunt fraction (Q’s/Q’t), alveolar dead space (Vd/Vtalv) and ventilation/perfusion mismatch (V’ A /Q’). Methods This was an international, prospective, observational, multicenter, cohort study, including six intensive care units in Sweden and Poland and 71 mechanically ventilated adult patients. Results Prone position increased PaO 2 :FiO 2 after 30 min, by 78% (83–148 mm Hg). The effect persisted 120 min after return to supine ( p  < 0.001). The oxygenation index decreased 30 min after prone positioning by 43% (21–12 units). Q’s/Q’t decreased already after 30 min in the prone position by 17% (0.41–0.34). The effect persisted 120 min after return to supine ( p  < 0.005). Q’s/Q’t and PaO 2 :FiO 2 were correlated both in prone (Beta -137) ( p  < 0.001) and in the supine position (Beta -270) ( p  < 0.001). V’ A /Q’ was unaffected and did not correlate to PaO 2 :FiO 2 ( p  = 0.8). Vd/Vtalv increased at 120 min by 11% (0.55–0.61) ( p  < 0.05) and did not correlate to PaO 2 :FiO 2 ( p  = 0.3). The ventilatory ratio increased after 30 min in the prone position by 58% (1.9–3.0) ( p  < 0.001). PaO 2 :FiO 2 at baseline predicted PaO 2 :FiO 2 at 30 min after proning (Beta 1.3) ( p  < 0.001). Conclusions Improved oxygenation by prone positioning in COVID-19 ARDS patients was primarily associated with a decrease in pulmonary shunt fraction. Dead space remained high and the global V’ A /Q’ measure could not explain the differences in gas exchange.

Assessment of oxygenation is fundamental to the care of patients. Numerous indices of oxygenation have been developed that entail variable degrees of invasiveness, complexity and physiologic underpinning. The clinical reliability of these indices has been questioned. This theoretical study uses a steady-state model of blood gas physiology to study the assumptions and nonpulmonary factors that have been hypothesized to impact index performance. A model derived from cardiac and pulmonary Fick expressions was used to calculate the effects of the physiological parameters—shunt, dead space, cardiac output, ventilation, oxygen extraction, carbon dioxide elimination, hematocrit, temperature and base excess—on predicted arterial, mixed-venous and post-capillary oxygen contents and arterial and alveolar oxygen and carbon dioxide partial pressures. Values of these parameters were determined over a range of shunt from 0 to 50% and then used to calculate (1) estimated shunt with the shunt equation and FShunt, and (2) the alveolar-arterial partial pressure of oxygen difference (A-a O2 gradient), and the arterial partial pressure of oxygen to fraction of inspired oxygen (Pa/Fi) ratio. Calculations were performed either treating parameters as fixed (assuming several values) or as random variables. Assumptions of constant arterio-venous oxygen content and of alveolar and arterial partial pressures of carbon dioxide being equal were shown to fail in certain settings where shunt and physiologic parameters varied. These effects manifested as calculated indices either over or under-estimating actual shunt by FShunt, or wide unpredictable variability (scatter) when correlating A-a O2 gradient and Pa:Fi ratio to actual shunt. Cardiac output and oxygen extraction have noticeable impacts on all calculated indices. The results support the clinical observations that the performance of indices of oxygenation can vary with fraction of inspired oxygen and various nonpulmonary physiological factors that underly heterogeneity present in the clinical population.

Background99mTc-macroaggregated albumin (99mTc-MAA) scintigraphy is utilized in treatment planning for Yttrium-90 (90Y) Selective Internal Radiation Therapy (SIRT) of liver tumors to evaluate hepatopulmonary shunting by calculating the lung shunt fraction (LSF). The purpose of this study was to evaluate if LSF calculation using SPECT/CT instead of planar gamma camera imaging is more accurate and if this can potentially lead to more effective treatment planning of hepatic lesions while avoiding excessive pulmonary irradiation.ResultsLSF calculation was obtained using two different methodologies in 85 cases from consecutive patients intended to receive 90Y SIRT. The first method was based on planar gamma camera imaging in the anterior and posterior views with geometric mean calculation of the LSF from regions of interest of the liver and lungs. The second method was based on segmentation of the liver and lungs from SPECT/CT images of the thorax and abdomen. The differences in planar imaging versus SPECT/CT derived LSF values along with the estimated absorbed lung mean dose (LMD) were evaluated. The LSF values were higher in planar imaging versus SPECT/CT in 81/85 cases, with a mean value of 8.5% vs. 4.6% respectively; the difference was statistically significant using a paired t-test (alpha = 0.05). In those patients who received SIRT, the estimated absorbed LMD calculated with planar imaging was significantly higher than with SPECT/CT (t-test, P < 0.005). Repeated phantom experiments using an anthropomorphic torso phantom with variable 99mTc activity concentrations for the liver and lungs were performed with the standard patient protocol, demonstrated improved accuracy of the LSF calculation based on SPECT/CT than planar imaging (mean overestimated value of 6% vs. 26%).ConclusionsThis study demonstrates that LSF calculation using planar imaging can be significantly overestimated while calculation using SPECT/CT imaging and appropriate segmentation tools can be more accurate. Minimizing the errors in obtaining the LSF can lead to more effective 90Y SIRT treatment planning for hepatic tumors while ensuring the lung dose will not exceed the standard acceptable safety thresholds.

Background Prior studies have established that macroaggregated albumin (MAA)-SPECT/CT offers more robust lung shunt fraction (LSF) and lung mean absorbed dose (LMD) estimates in 90 Y radioembolization in comparison to planar imaging. However, incomplete SPECT/CT coverage of the lungs is common due to clinical workflows, complicating its potential use for LSF and LMD calculations. In this work, lung truncation in MAA-SPECT/CT was addressed via correction strategies to improve 90 Y treatment planning. Methods Lung truncation was simulated in 56 cases with adequate (> 90%, mean: 98%) lung coverage in MAA-SPECT/CT by removing slices in ~ 5 mm increments from the lung apices to the diaphragm. A wide range of lung coverages from 100% to < 1% in ~ 2% increments were created. LSF and LMD were calculated with four methods. (1) 2D planar imaging standard (not truncated), truncated lung SPECT/CT data was: (2) used with no corrections (SPECT Trunc ), (3) uniformly extrapolated to full lung coverage (SPECT Uniform ), (4) fit with an empirical model to predict lung counts at full lung coverage (SPECT Fit ). To determine counts for LSF, full lung volumes, those modified at the lung/liver boundary (Lungs 2-cm), and those isolated to the left lung (Left Lung) were used. The correction methods were then applied to 31 independent cases without full lung coverage (< 90%, mean: 74%). The variations in LSF and LMD estimates from each correction method were analyzed. Results Averaged across simulated lung coverages from 40 to 80%, percent errors relative to non-truncated data for SPECT Trunc were (mean ± σ) − 22% ± 15% for LSF and 34% ± 29% for LMD. SPECT Uniform had similar errors with 29% ± 26% for both LSF and LMD. SPECT Fit yielded the most accurate and precise estimates for LSF and LMD, with errors of 11% ± 20% for both. The Left Lung approach equalized LMD errors in all three correction methods, with percent errors of 3% ± 17% (SPECT Trunc ), 2% ± 17% (SPECT Uniform ), and 4% ± 13% (SPECT Fit ). In the 31 cases without ground truth LSF or LMD, Left Lung produced highly comparable LMD estimates, with a mean (max) coefficient of variation across the three correction methods of 4% (20%). Conclusion LSF and LMD can be estimated for 90 Y radioembolization using truncated lung coverage data in MAA-SPECT/CT. Empirical models to predict lung counts at full lung coverage produced LSF and LMD estimates with minimal bias and uncertainty. With lung/liver boundary adjustments, all SPECT/CT methods assessed in this work yielded LMD estimates comparable to ground truth, even down to 50% lung coverage.

Objective Transarterial radioembolization (TARE) with Yttrium-90 ( 90 Y) labeled microspheres is an effective locoregional treatment option for patients with primary and metastatic liver cancer. However, TARE is also associated with radiation-induced lung injury due to hepatopulmonary shunting. If a large proportion of the injected radionuclide microspheres (more than 15%) is shunted, a rare but lethal complication may develop: radiation-induced pneumonitis (RP). Diffusion capacity of the lungs for carbon monoxide (DLCO) is a valuable test to assess lung function and a decrease in DLCO may indicate an impairment in gas exchange caused by the lung injury. Some previous researches have been reported the most consistent changes in pulmonary function tests after external beam radiotherapy are recorded with DLCO. This study aimed to examine the changes in DLCO after TARE with glass microspheres in newly treated and retreated patients with relatively higher lung shunt fractions. Methods We prospectively analyzed forty consecutive patients with liver malignancies who underwent lobar or superselective TARE with 90 Y glass microspheres. DLCO tests were performed at baseline and on days 15, 30, and 60 after the treatment. All patients were followed up clinically and radiologically for the development of RP. Results A statistically significant decrease was found in the DLCO after the first treatment (81.4 ± 13.66 vs. 75.25 ± 13.22,  p  = 0.003). The frequency of the patients with impaired DLCO at baseline was significantly increased after the first treatment (37.5 vs 57.5% p  < 0.05). In the retreated group ( n  = 8), neither the DLCO (71.5 ± 10.82 vs. 67.50 ± 11.24,  p  = 0.115) nor the frequency of patients with impaired DLCO (25 vs 25%, p  = 1) did not significantly change. Also, the change in DLCO values did not significantly correlate with lung shunt fraction, administered radiation dose, and absorbed lung dose after the first and second treatments ( p  > 0.05 for all). None of the patients developed RP. Conclusion Our study showed that a significant reduction in DLCO after TARE may occur in patients with relatively higher lung shunt fractions. Further studies with larger sample sizes are needed to better investigate the changes in DLCO in patients with high lung shunt fractions.

Introduction: Although the incidence of mechanical complications of myocardial infarction is decreasing, the associated mortality rate remains high. Such complications require an early diagnosis and multidisciplinary management. In most cases, surgery is the only definitive treatment, despite it being associated with high peri-operative mortality and morbidity. An intra-aortic balloon pump (IABP) or Extracorporeal Membrane Oxygenation (ECMO) may also be required for unstable patients. After the employment of mechanical assistance, ultrasound and chemical parameters are associated with successful weaning, indicating adequate cardiac function, perfusion, and oxygen delivery. Case presentation: The aim of this case report is to describe the weaning from the extracorporeal support in a case of post-myocardial-infarction ventricular septal defect (VSD) and Left ventricle (LV) apical aneurysm. The patient underwent surgery for VSD closure and aneurysm exclusion. After the emergency surgery, the patient developed a severe post-cardiotomy cardiogenic shock, which required veno-arterial femoral–femoral extracorporeal membrane oxygenation (VA-ff-ECMO), IABP, and maximal pharmacologic support. During the ICU stay, we weaned the patient from the ECMO support based on transesophageal echocardiography (TEE) imaging and pulmonary artery catheter (PAC) monitoring and quantified the shunt fraction. On the fifth post-operative day, we started the weaning trial. Hemodynamic and ultrasound monitoring showed an adequate cardiac function, and the shunt fraction calculated with both the ultrasound parameters and Fick’s law was acceptable. We removed the ECMO the day after, and the weaning was successful. Discussion: Data deriving from the Swan–Ganz catheter has been found to be important in guiding the process of weaning a patient from extracorporeal support. Nevertheless, the TEE played a pivotal role in the decision-making process and in clinical management. We reduced the ECMO blood flow following a real-time echocardiographic cardiac function assessment. Conclusions: Following the fundamental guides for both PAC monitoring and TEE imaging, we successfully removed the extracorporeal support, with a positive outcome.

Background Prior to selective internal radiotherapy of liver tumors, a determination of the lung shunt fraction (LSF) is performed using 99mTc- macroaggregated albumin (99mTc-MAA) injected into the hepatic artery. Most commonly planar but sometimes SPECT/CT images are acquired upon which regions of interests are drawn manually to define the liver and the lung. The LSF is then calculated by taking the count ratios between these two organs. An accurate estimation of the LSF is necessary to avoid an excessive pulmonary irradiation dose. Methods In this study, we propose a computational, semi-automatic approach for LSF calculation from SPECT/CT scans, based on machine learning 3D segmentation, implemented within TriDFusion (3DF). We retrospectively compared this approach with the LSF calculated using the standard planar approach on 150 patients. Using CT images (from the SPECT/CT) as a blueprint, the TotalSegmentor machine learning algorithm automatically computes masks for the liver and lungs. Then, the SPECT attenuation-corrected images are fused with the CT and, based on the CT segmentation mask, TriDFusion (3DF) generates volume-of- interest (VOI) regions on the SPECT images. The liver and lung VOIs are further augmented to compensate for breathing motion. Finally, the LSF is calculated using the number of counts in the respective VOIs. Measurements using an anthropomorphic 3D-printed phantom with variable 99mTc activity concentrations for the liver and lungs were performed to validate the accuracy of the algorithm. Results On average, LSF determined from 2D planar images were between 21 and 70% higher than those determined from SPECT/CT data. Semi-automated determination of the LSF using TriDFusion (3DF) analysis of SPECT-CT acquisitions was within 4–12% of the phantom-determined ratio measurements (ground truth). Conclusions The utilization of TriDFusion (3DF) AI 3D Lung Shunt is a precise method for quantifying lung shunt fraction (LSF) and is more accurate than planar 2D image-based estimates. By incorporating machine learning segmentation and compensating for breathing motion, the approach underscores the potential of artificial intelligence (AI)-driven techniques to revolutionize pulmonary imaging, providing clinicians with efficient and reliable tools for treatment planning and patient management.