Extracorporeal membrane oxygenation for general thoracic surgery: case series and narrative review.

Background and Objective: Extracorporeal membrane oxygenation (ECMO) has historically been utilized as a temporary life support option for patients with severe cardiac and pulmonary dysfunction. Recent advancements have enabled the safe application of ECMO in a wider variety of patients; we present a review of its use in patients undergoing general thoracic procedures supported by a case series at our institution. Methods: We review current literature focusing on ECMO applications in thoracic surgery outside of the traditional use. Additionally, we offer three cases of ECMO utilization to illustrate success stories and key lessons learned regarding the use of ECMO in general thoracic surgery. Key Content and Findings: Technologic advancements and enhanced safety profiles have enabled the safe application of ECMO in a wide array of patients far beyond the historic indications of cardiogenic shock and acute respiratory distress syndrome (ARDS). It is now feasible to consider ECMO for management of acute thoracic emergencies, as well as to better facilitate operative safety in complex general thoracic surgical procedures. Both venovenous and venoarterial ECMO can be utilized in carefully selected patients to provide cardiopulmonary support while enabling improved visualization and increased mobilization without concern for respiratory and/or cardiac compromise. Conclusions: Enthusiasm for the use of ECMO has increased in recent years. What was once considered a salvage therapy in cases of life-threatening cardiopulmonary decompensation now plays an increasingly important role in the safe conduct of complex thoracic surgery procedures, provides much needed time for organ recovery, and offers acute resuscitation options. This shift broadens our ability to deliver life-saving care to patients that previously would have otherwise had limited treatment options.

Improved atmospheric constraints on Southern Ocean CO2 exchange.

We present improved estimates of air-sea CO2 exchange over three latitude bands of the Southern Ocean using atmospheric CO2 measurements from global airborne campaigns and an atmospheric 4-box inverse model based on a mass-indexed isentropic coordinate (Mθe). These flux estimates show two features not clearly resolved in previous estimates based on inverting surface CO2 measurements: a weak winter-time outgassing in the polar region and a sharp phase transition of the seasonal flux cycles between polar/subpolar and subtropical regions. The estimates suggest much stronger summer-time uptake in the polar/subpolar regions than estimates derived through neural-network interpolation of pCO2 data obtained with profiling floats but somewhat weaker uptake than a recent study by Long et al. [Science 374, 1275-1280 (2021)], who used the same airborne data and multiple atmospheric transport models (ATMs) to constrain surface fluxes. Our study also uses moist static energy (MSE) budgets from reanalyses to show that most ATMs tend to have excessive diabatic mixing (transport across moist isentrope, θe, or Mθe surfaces) at high southern latitudes in the austral summer, which leads to biases in estimates of air-sea CO2 exchange. Furthermore, we show that the MSE-based constraint is consistent with an independent constraint on atmospheric mixing based on combining airborne and surface CO2 observations.

Tracheostomy in high-risk patients on ECMO: A bedside hybrid dilational technique utilizing a Rummel tourniquet.

Objective: Traditionally, critically ill patients requiring prolonged mechanical ventilation benefit from a long-term airway, thus necessitating tracheostomy. The widespread application of extracorporeal membrane oxygenation (ECMO) has exponentially increased in recent years, creating a new subset of patients necessitating tracheostomy with significantly increased bleeding risk. We present a hybrid dilational tracheostomy technique utilizing a Rummel tourniquet developed at our institution to mitigate bleeding risk in patients on ECMO necessitating long-term airway. Methods: A total of 24 patients on ECMO underwent bedside hybrid dilational tracheostomy with utilization of a Rummel tourniquet from 06/2020 to 01/2022 at our institution. These patients were followed longitudinally and evaluated for postoperative bleeding. Particular attention was paid to anticoagulation regimens pre- and post-operatively. Results: The primary outcome of the study, postoperative bleeding, was observed in four of the 24 study participants (16.67 %). Each of these complications were managed with tightening of the Rummel tourniquet and application of hemostatic packing agents; no operative interventions were required. Anticoagulation was held for a mean time of 4.33 h preoperatively and 5.2 h postoperatively. Conclusions: Our data support this hybrid tracheostomy technique with the addition of a Rummel tourniquet to be a safe and effective adjunct for perioperative hemostasis in high-risk patients necessitating tracheostomy while on ECMO. While this technique was initially developed for critically ill COVID-19 patients, we believe it can be applied to all patients on ECMO to help mitigate perioperative bleeding risk.

Hyperthermic intrapleural chemotherapy: an update.

The safety and efficacy of hyperthermic intrathoracic chemotherapy (HITHOC) as an adjunct to cytoreductive surgery (CRS) in pleural malignancies has been well demonstrated. This is most often described in cases of mesothelioma, thymoma, or other secondary pleural metastases. The utilization of a direct cytotoxic agent with increased penetration secondary to a hyperthermic environment is especially beneficial in pleural malignancy as a microscopic resection remains immensely challenging. Despite favorable outcomes with a limited associated risk profile, there persists a variety in utilization and technique of HITHOC described in current literature. National Comprehensive Cancer Network (NCCN) guidelines state that though intraoperative adjuvant therapies such as HITHOC have been studied, they remain of unclear benefit and definitive recommendations do not currently exist. This ambiguity limits the standardization of HITHOC, thus hindering its further application in a patient population with exceedingly poor outcomes within current guideline-based therapy. As the prevalence of pleural malignancies necessitating CRS with adjuvant HITHOC remains quite low, we believe a task force initiative to further investigate the role of HITHOC in surgical management of pleural malignancies would enable wider utility of this promising technique. Additionally, we propose that the creation of a pleural cancer index could aid in standardization of HITHOC in those with pleural malignancy.

Spontaneous middle lobe torsion: An institutional case series.

Objective: Lobar torsion is a rare occurrence in which a portion of the lung is twisted on its bronchovascular pedicle. The vast majority are observed in the acute postoperative period often following right upper lobectomy. Spontaneous middle lobe torsion independent of pulmonary resection is exceptionally rarer; fewer than 15 cases have been recorded. We present an institutional case series of 2 patients postorthotopic liver transplantation who developed spontaneous middle lobe torsion due to large pleural effusions. Methods: We provide the medical course as well as intraoperative techniques for our 2 patients along with a review of the literature. Results: Both patients in this case series underwent orthotopic liver transplant complicated postoperatively by a large pulmonary effusion. Patient one developed an abdominal hematoma requiring evacuation and repair, after which he developed progressive shortness of breath. Bronchoscopy revealed a right middle lobe obstruction; upon thoracotomy, 180-degree torsion with widespread necrosis was evident and the middle lobe was removed. He is doing well to date. Patient 2 experienced postoperative pleural effusion and mucus plugging; computed tomography revealed abrupt middle lobe arterial occlusion prompting urgent operative intervention. Again, the middle lobe was grossly ischemic and dissection revealed a 360-degree torsion around the pedicle. It was resected. He is doing well to date. Conclusions: As the result of its rarity, radiographic and clinical diagnosis of spontaneous pulmonary lobar torsion is challenging; a high index of suspicion for spontaneous middle lobe torsion must be maintained to avoid delays in diagnosis. Prompt surgical intervention is essential to improve patient outcomes.

The utility of machine learning for predicting donor discard in abdominal transplantation.

BACKGROUND: Increasing access and better allocation of organs in the field of transplantation is a critical problem in clinical care. Limitations exist in accurately predicting allograft discard. Potential exists for machine learning to provide a balanced assessment of the potential for an organ to be used in a transplantation procedure. METHODS: We accessed and utilized all available deceased donor United Network for Organ Sharing data from 1987 to 2020. With these data, we evaluated the performance of multiple machine learning methods for predicting organ use. The machine learning methods trialed included XGBoost, random forest, Naïve Bayes (NB), logistic regression, and fully connected feedforward neural network classifier methods. The top two methods, XGBoost and random forest, were fully developed using 10-fold cross-validation and Bayesian optimization of hyperparameters. RESULTS: The top performing model at predicting liver organ use was an XGBoost model which achieved an AUC-ROC of .925, an AUC-PR of .868, and an F1 statistic of .756. The top performing model for predicting kidney organ use classification was an XGBoost model which achieved an AUC-ROC of .952, and AUC-PR of .883, and an F1 statistic of .786. CONCLUSIONS: The XGBoost method demonstrated a significant improvement in predicting donor allograft discard for both kidney and livers in solid organ transplantation procedures. Machine learning methods are well suited to be incorporated into the clinical workflow; they can provide robust quantitative predictions and meaningful data insights for clinician consideration and transplantation decision-making.

nnU-Net Deep Learning Method for Segmenting Parenchyma and Determining Liver Volume From Computed Tomography Images.

Background: Recipient donor matching in liver transplantation can require precise estimations of liver volume. Currently utilized demographic-based organ volume estimates are imprecise and nonspecific. Manual image organ annotation from medical imaging is effective; however, this process is cumbersome, often taking an undesirable length of time to complete. Additionally, manual organ segmentation and volume measurement incurs additional direct costs to payers for either a clinician or trained technician to complete. Deep learning-based image automatic segmentation tools are well positioned to address this clinical need. Objectives: To build a deep learning model that could accurately estimate liver volumes and create 3D organ renderings from computed tomography (CT) medical images. Methods: We trained a nnU-Net deep learning model to identify liver borders in images of the abdominal cavity. We used 151 publicly available CT scans. For each CT scan, a board-certified radiologist annotated the liver margins (ground truth annotations). We split our image dataset into training, validation, and test sets. We trained our nnU-Net model on these data to identify liver borders in 3D voxels and integrated these to reconstruct a total organ volume estimate. Results: The nnU-Net model accurately identified the border of the liver with a mean overlap accuracy of 97.5% compared with ground truth annotations. Our calculated volume estimates achieved a mean percent error of 1.92% + 1.54% on the test set. Conclusions: Precise volume estimation of livers from CT scans is accurate using a nnU-Net deep learning architecture. Appropriately deployed, a nnU-Net algorithm is accurate and quick, making it suitable for incorporation into the pretransplant clinical decision-making workflow.

A multi-city urban atmospheric greenhouse gas measurement data synthesis.

Urban regions emit a large fraction of anthropogenic emissions of greenhouse gases (GHG) such as carbon dioxide (CO2) and methane (CH4) that contribute to modern-day climate change. As such, a growing number of urban policymakers and stakeholders are adopting emission reduction targets and implementing policies to reach those targets. Over the past two decades research teams have established urban GHG monitoring networks to determine how much, where, and why a particular city emits GHGs, and to track changes in emissions over time. Coordination among these efforts has been limited, restricting the scope of analyses and insights. Here we present a harmonized data set synthesizing urban GHG observations from cities with monitoring networks across North America that will facilitate cross-city analyses and address scientific questions that are difficult to address in isolation.

Doege Potter syndrome presenting as multiple fibrous tumours of the chest.

Doege Potter syndrome is a rare condition causing non-islet cell paraneoplastic hypoglycaemia associated with fibrous tumours, which can be both benign and malignant. The vast majority are solitary and located within the chest. Non-islet cell tumour-induced hypoglycaemia, as in Doege Potter syndrome, is quite rare and occurs around 4 times less often than islet cell-associated paraneoplastic hypoglycaemia. We present a case of Doege Potter syndrome with severe hypoglycaemia in conjunction with multiple recurrent fibrous tumours of the lung and pleura.

Transcatheter aortic valve replacement outcomes in solid organ transplant recipients.

BACKGROUND AND AIMS: Transcatheter aortic valve replacement (TAVR) has become the primary treatment for severe symptomatic aortic stenosis in patients >65 years with volumes exceeding surgical aortic valve replacements (SAVR) since 2019. As a less invasive procedure with lower complication rates, TAVR is preferable in most patient populations, particularly those with increased surgical risk. One such population is patients who have undergone solid organ transplant (SOT). We aimed to evaluate periprocedural outcomes and complication rates following TAVR in SOT recipients as compared to the general TAVR population. METHODS: The 2016-2018 National Inpatient Sample (NIS) was queried by ICD-10 PCS codes to identify TAVR cases; hospitalizations were subsequently stratified by SOT history. Multivariate analyses were completed to evaluate complication rates, length of stay (LOS), and cost of stay (COS). RESULTS: No significant difference was observed in mortality rates or post-procedural complications between SOT recipients (n = 223) and those without transplant history undergoing TAVR (n = 29,448) except for increased thromboembolic events captured in transplant patients (p < .001). There was no significant variation in LOS or COS between the two populations; female sex and Black or Hispanic race were predictors of increased inpatient time. CONCLUSIONS: SOT recipients have no increased risk of mortality or periprocedural complications when undergoing TAVR. Though the rate of thromboembolic events was higher in SOT recipients, observation size was small (n = 27 TAVR, n = 4 TAVR + SOT) thus external validity is limited. Based on these data, transplant recipients experience no difference in outcomes following TAVR as compared to patients without a history of organ transplant.

Strong Southern Ocean carbon uptake evident in airborne observations.

The Southern Ocean plays an important role in determining atmospheric carbon dioxide (CO2), yet estimates of air-sea CO2 flux for the region diverge widely. In this study, we constrained Southern Ocean air-sea CO2 exchange by relating fluxes to horizontal and vertical CO2 gradients in atmospheric transport models and applying atmospheric observations of these gradients to estimate fluxes. Aircraft-based measurements of the vertical atmospheric CO2 gradient provide robust flux constraints. We found an annual mean flux of ­0.53 ± 0.23 petagrams of carbon per year (net uptake) south of 45°S during the period 2009­2018. This is consistent with the mean of atmospheric inversion estimates and surface-ocean partial pressure of CO2 (Pco2)­based products, but our data indicate stronger annual mean uptake than suggested by recent interpretations of profiling float observations.

Coupled Air Quality and Boundary-Layer Meteorology in Western U.S. Basins during Winter: Design and Rationale for a Comprehensive Study.

Wintertime episodes of high aerosol concentrations occur frequently in urban and agricultural basins and valleys worldwide. These episodes often arise following development of persistent cold-air pools (PCAPs) that limit mixing and modify chemistry. While field campaigns targeting either basin meteorology or wintertime pollution chemistry have been conducted, coupling between interconnected chemical and meteorological processes remains an insufficiently studied research area. Gaps in understanding the coupled chemical-meteorological interactions that drive high pollution events make identification of the most effective air-basin specific emission control strategies challenging. To address this, a September 2019 workshop occurred with the goal of planning a future research campaign to investigate air quality in Western U.S. basins. Approximately 120 people participated, representing 50 institutions and 5 countries. Workshop participants outlined the rationale and design for a comprehensive wintertime study that would couple atmospheric chemistry and boundary-layer and complex-terrain meteorology within western U.S. basins. Participants concluded the study should focus on two regions with contrasting aerosol chemistry: three populated valleys within Utah (Salt Lake, Utah, and Cache Valleys) and the San Joaquin Valley in California. This paper describes the scientific rationale for a campaign that will acquire chemical and meteorological datasets using airborne platforms with extensive range, coupled to surface-based measurements focusing on sampling within the near-surface boundary layer, and transport and mixing processes within this layer, with high vertical resolution at a number of representative sites. No prior wintertime basin-focused campaign has provided the breadth of observations necessary to characterize the meteorological-chemical linkages outlined here, nor to validate complex processes within coupled atmosphere-chemistry models.

Unpiloted Aircraft System Instrument for the Rapid Collection of Whole Air Samples and Measurements for Environmental Monitoring and Air Quality Studies.

A new airborne system, the Whole Air Sampling Pilotless Platform (WASPP), is described for the collection of whole air samples and in situ meteorological measurements onboard a commercial hexacopter. Rapid sample collection enables the collection ≤15 air samples per flight in positively pressurized miniature canisters, subsequently analyzed on a mated analytical system for up to 80 nonmethane volatile organic compounds (VOCs). The WASPP is well suited to investigate VOC gradients in urban environments impacted by traffic, industry, and oil and natural gas (O&NG) development, but has the sensitivity to characterize continental background conditions, as shown here using a subset of >40 species. We document empirical tests to minimize the influence of rotor wash and other sampling artifacts and report favorable results of laboratory-based calibrations of the WASPP's meteorological sensors and field-based comparisons of WASPP's VOC measurements and horizontal wind velocity measurements. Airborne WASPP measurements can complement and enhance ground-based VOC monitoring efforts by providing substantial meteorological and VOC measurement capability across vertical and horizontal spatial scales. These measurements reveal strong vertical gradients in VOC mixing ratios, depending on local meteorology and sources. WASPP has wide applicability for pollution source identification and quantification of hazardous air pollutants and precursors of criteria pollutants, including monitoring O&NG emissions or industry fenceline monitoring.

Global atmospheric CO2 inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate.

We have compared a suite of recent global CO2 atmospheric inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO2 concentration profiles against observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) aircraft campaigns over the mid-Pacific in 2009-2011. Although the models differ in inverse approaches, assimilated observations, prior fluxes, and transport models, their broad latitudinal separation of land fluxes has converged significantly since the Atmospheric Carbon Cycle Inversion Intercomparison (TransCom 3) and the REgional Carbon Cycle Assessment and Processes (RECCAP) projects, with model spread reduced by 80% since TransCom 3 and 70% since RECCAP. Most modeled CO2 fields agree reasonably well with the HIPPO observations, specifically for the annual mean vertical gradients in the Northern Hemisphere. Northern Hemisphere vertical mixing no longer appears to be a dominant driver of northern versus tropical (T) annual flux differences. Our newer suite of models still gives northern extratropical land uptake that is modest relative to previous estimates (Gurney et al., 2002; Peylin et al., 2013) and near-neutral tropical land uptake for 2009-2011. Given estimates of emissions from deforestation, this implies a continued uptake in intact tropical forests that is strong relative to historical estimates (Gurney et al., 2002; Peylin et al., 2013). The results from these models for other time periods (2004-2014, 2001-2004, 1992-1996) and reevaluation of the TransCom 3 Level 2 and RECCAP results confirm that tropical land carbon fluxes including deforestation have been near neutral for several decades. However, models still have large disagreements on ocean-land partitioning. The fossil fuel (FF) and the atmospheric growth rate terms have been thought to be the best-known terms in the global carbon budget, but we show that they currently limit our ability to assess regional-scale terrestrial fluxes and ocean-land partitioning from the model ensemble.

Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth.

Cities are concentrated areas of CO2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO2 mole fractions from five sites across Utah's metropolitan Salt Lake Valley. We examine "excess" CO2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO2 trends to changes in emissions, since we did not find long-term trends in atmospheric mixing proxies. Three contrasting CO2 trends emerged across urban types: negative trends at a residential-industrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of population within the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO2, implying a nonlinear relationship with CO2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles.

Reduced prevalence of pain and distress during 4 years of screening with QUICATOUCH in Australian oncology patients.

While psychosocial screening has been recommended in oncology for some time, widespread adoption in clinical practice has lagged. The QUICATOUCH program is one example of sustained clinic-level screening, assessment and referral. We examined whether this program was associated with reductions in pain or distress. Oncology outpatients completed a brief, computerised assessment using Distress and Pain Thermometers. We describe population levels of pain and distress and model pain and distress scores over 4 years of the program. 9,133 patients were screened on 26,385 occasions over 48 months (October 2007-September 2011). Pain over threshold (1/10) reduced over time, from 33% in the first 3 months to 16% in the final quarter of the evaluation. Distress over threshold (4/10) reduced from 28% to 10%. A reduction was also observed when restricted to patients screened for the first time. Our analysis demonstrated this effect was not explained by measured potential confounders (gender, age, treatment status) and was unlikely to be attributable to regression to the mean. Observational studies cannot prove causation. However, the significant reduction in pain and distress levels in the 48 months following commencement of QUICATOUCH is consistent with a beneficial effect of the program.

Heads Up: a pilot trial of a psychological intervention to improve nutrition in head and neck cancer patients undergoing radiotherapy.

Malnutrition in head and neck cancer (HNC) patients is common and associated with poorer radiotherapy outcomes including increased mortality. This pilot trial investigates the feasibility and effectiveness of a psychological intervention to improve nutritional status, depression and mortality in HNC patients undergoing radiotherapy. Fifty-nine intervention patients received motivational interviewing and cognitive behavioural therapy compared to 70 historical controls who received treatment as usual. Participants were assessed for nutrition, depression and mortality. There were no significant differences between groups in nutritional status, depression or mortality. Subgroup analyses among patients at greater nutritional risk (cancers of the oral cavity, pharynx, larynx) revealed a potentially clinically important reduction on the PG-SGA and lower mortality (31% of controls vs. 16% intervention; P = 0.03) in favour of the intervention condition. Potential benefits in nutritional status and in mortality in this pilot trial of a psychological intervention among HNC patients at high nutritional risk suggest that a larger randomised controlled trial is warranted.

Doxorubicin chemotherapy for presumptive cardiac hemangiosarcoma in dogs†.

Sixty-four dogs were treated with single-agent doxorubicin (DOX) for presumptive cardiac hemangiosarcoma (cHSA). The objective response rate (CR + PR) was 41%, and the biologic response rate (CR + PR + SD), or clinical benefit, was 68%. The median progression-free survival (PFS) for treated dogs was 66 days. The median survival time (MST) for this group was 116 days and was significantly improved compared to a MST of 12 days for untreated control dogs (P = 0.0001). Biologic response was significantly associated with improved PFS (P < 0.0001) and OS (P < 0.0001). Univariate analysis identified larger tumour size as a variable negatively associated with PFS. The high rate of clinical benefit and improved MST suggest that DOX has activity in canine cHSA.

Effect of increasing CO2 on the terrestrial carbon cycle.

Feedbacks from the terrestrial carbon cycle significantly affect future climate change. The CO2 concentration dependence of global terrestrial carbon storage is one of the largest and most uncertain feedbacks. Theory predicts the CO2 effect should have a tropical maximum, but a large terrestrial sink has been contradicted by analyses of atmospheric CO2 that do not show large tropical uptake. Our results, however, show significant tropical uptake and, combining tropical and extratropical fluxes, suggest that up to 60% of the present-day terrestrial sink is caused by increasing atmospheric CO2. This conclusion is consistent with a validated subset of atmospheric analyses, but uncertainty remains. Improved model diagnostics and new space-based observations can reduce the uncertainty of tropical and temperate zone carbon flux estimates. This analysis supports a significant feedback to future atmospheric CO2 concentrations from carbon uptake in terrestrial ecosystems caused by rising atmospheric CO2 concentrations. This feedback will have substantial tropical contributions, but the magnitude of future carbon uptake by tropical forests also depends on how they respond to climate change and requires their protection from deforestation.