Crowd-Sourced Deep Learning for Intracranial Hemorrhage Identification: Wisdom of Crowds or Laissez-Faire.

BACKGROUND AND PURPOSE: Researchers and clinical radiology practices are increasingly faced with the task of selecting the most accurate artificial intelligence tools from an ever-expanding range. In this study, we sought to test the utility of ensemble learning for determining the best combination from 70 models trained to identify intracranial hemorrhage. Furthermore, we investigated whether ensemble deployment is preferred to use of the single best model. It was hypothesized that any individual model in the ensemble would be outperformed by the ensemble. MATERIALS AND METHODS: In this retrospective study, de-identified clinical head CT scans from 134 patients were included. Every section was annotated with "no-intracranial hemorrhage" or "intracranial hemorrhage," and 70 convolutional neural networks were used for their identification. Four ensemble learning methods were researched, and their accuracies as well as receiver operating characteristic curves and the corresponding areas under the curve were compared with those of individual convolutional neural networks. The areas under the curve were compared for a statistical difference using a generalized U-statistic. RESULTS: The individual convolutional neural networks had an average test accuracy of 67.8% (range, 59.4%-76.0%). Three ensemble learning methods outperformed this average test accuracy, but only one achieved an accuracy above the 95th percentile of the individual convolutional neural network accuracy distribution. Only 1 ensemble learning method achieved a similar area under the curve as the single best convolutional neural network (Δarea under the curve = 0.03; 95% CI, -0.01-0.06; P = .17). CONCLUSIONS: None of the ensemble learning methods outperformed the accuracy of the single best convolutional neural network, at least in the context of intracranial hemorrhage detection.

Intraoperative TOE guided management of newly diagnosed severe tricuspid regurgitation and pulmonary hypertension during orthotopic liver transplantation: a case report demonstrating the importance of reversibility as a favorable prognostic factor.

BACKGROUND: Tricuspid regurgitation (TR) and pulmonary hypertension (PHT) are highly dynamic cardiovascular lesions that may progress rapidly, particularly in the orthotopic liver transplantation (OLT) waitlist population. Severe TR and PHT are associated with poor outcomes in these patients, however it is rare for the two to be newly diagnosed intraoperatively at the time of OLT. Without preoperative information on pulmonary vascular and right heart function, the potential for reversibility of severe TR and PHT is unclear, making the decision to proceed to transplant fraught with difficulty. CASE PRESENTATION: We present a case of successful orthotopic liver transplantation (OLT) in a 48 year old female with severe (PHT) (mean pulmonary arterial pressure > 55 mmHg) and severe TR diagnosed post induction of anaesthesia. The degree of TR was associated with systemic venous pressures of > 100 mmHg resulting in massive haemorrhage during surgery and difficulty in distinguishing venous from arterial placement of vascular access devices. Intraoperative transoesophageal echocardiography (TOE) proved crucial in diagnosing functional TR due to tricuspid annular and right ventricular (RV) dilatation, and dynamically monitoring response to treatment. In response to positioning, judicious volatile anaesthesia administration, pulmonary vasodilator therapy and permissive hypovolemia during surgery we noted substantial improvement of the TR and pulmonary arterial pressures, confirming the reversibility of the TR and associated PHT. CONCLUSION: TR and PHT are co-dependent, dynamic, load sensitive right heart conditions that are interdependent with chronic liver disease, and may progress rapidly in patients waitlisted for OLT. Use of intraoperative TOE and pulmonary artery catheterisation on the day of surgery will detect previously undiagnosed severe TR and PHT, enable rapid assessment of the cause and the potential for reversibility. These dynamic monitors permit real-time assessment of the response to interventions or events affecting right ventricular (RV) preload and afterload, providing critical information for prognosis and management. Furthermore, we suggest that TR and PHT should be specifically sought when waitlisted OLT patients present with hepatic decompensation.

Associations of fluid amount, type, and balance and acute kidney injury in patients undergoing major surgery.

Fluid administration has been reported to be associated with an increased risk of acute kidney injury (AKI). We assessed whether, after correction for fluid balance, amount and chloride content of fluids administered have an independent association with AKI. We performed an observational study in patients after major surgery assessing the independent association of AKI with volume, chloride content and fluid balance, after adjustment for Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM) score, age, elective versus emergency surgery, and duration of surgery. We studied 542 consecutive patients undergoing major surgery. Of these, 476 patients had renal function tested as part of routine clinical care and 53 patients (11.1%) developed postoperative AKI. After adjustments, a 100 ml greater mean daily fluid balance was artificially associated with a 5% decrease in the instantaneous hazard of AKI: adjusted Hazard Ratio (aHR) 0.951, 95% confidence intervals (CI) 0.935 to 0.967, P <0.001. However, after adjustment for the proportion of chloride-restrictive fluids, mean daily fluid amounts and balances, POSSUM morbidity, age, duration and emergency status of surgery, and the confounding effect of fluid balance, every 5% increase in the proportion of chloride-liberal fluid administered was associated with an 8% increase in the instantaneous hazard of AKI (aHR 1.079, 95% CI 1.032 to 1.128, P=0.001), and a 100 ml increase in mean daily fluid amount given was associated with a 6% increase in the instantaneous hazard of AKI (aHR 1.061, 95% CI 1.047 to 1.075, P <0.001). After adjusting for key risk factors and for the confounding effect of fluid balance, greater fluid administration and greater administration of chloride-rich fluid were associated with greater risk of AKI.

Novel transoesophageal echocardiographic views attain superior incident angles for tricuspid, but not pulmonary, valvular Doppler interrogation.

For accurate spectral Doppler valvular evaluation, intraoperative sonographers must use transoesophageal echocardiographic (TOE) views that offer optimal incident angles. We hypothesised that views added to the 2013 American Society of Echocardiography/Society of Cardiovascular Anesthesiologists (ASE/SCA) standard views and other novel views we have described of the tricuspid (TV) and pulmonary valves (PV) offered superior incident angles to those included in the original 1999 ASE/SCA recommendations for comprehensive intraoperative TOE examination. We compared the acquisition feasibility and incident angles obtained by these views in 62 patients undergoing elective cardiac surgery, who received TOE monitoring as standard care. Overall, the 2013 ASE/SCA standard and novel views provided superior incident angles for the TV (28% and 66% of patients) whereas the 1999 ASE/SCA standard views provided superior incident angles for the PV (79% of patients, P <0.0001). The novel 90° mid-oesophageal modified bicaval view (90°MEMBC) and the 1999 ASE/SCA standard aortic arch short-axis view (AoArSAX) obtained best incident angles for the TV (mean [95% confidence interval] 13° [10°-16°]) and PV (5° [3°-7°]) respectively. PV view acquisition feasibility between the 1999 ASE/SCA standard, 2013 ASE/SCA standard and novel views was not significantly different (acquisition rate difference 11%, P ≥0.11). We conclude that the 2013 ASE/SCA TV standard and novel views obtained superior incident angles for the tricuspid, but not pulmonary valves. We recommend that intraoperative sonographers consider the use of these views, particularly when incident angles obtained with standard views are suboptimal.

Changing patterns in volatile anaesthetic agent consumption over seven years in Victorian public hospitals.

Evidence-based choices of volatile agents can increase health cost efficiencies. In this pharmaco-economic study, we evaluated the trends and costs of volatile agent use in Australian public hospitals. The total number of volatile agent (isoflurane, sevoflurane and desflurane) bottles ordered and inflation-adjusted costs were collected from 65 Victorian public hospitals from 2005 to 2011. Environmental costs were measured through the 100-year global warming potential index as carbon dioxide equivalents. During this time period, the aggregate inflation-adjusted expenditure was $39,209,878. Time series analysis showed that bottles of isoflurane ordered decreased by 419/year (99% confidence interval (CI): -603 to -235); costs decreased by $56,017/year (99% CI: -$93,243 to -$18,791). Bottles of sevoflurane increased by 1,330/year (99% CI: 1141 to 1,519); costs decreased by $423,3573/year (99% CI: -$720,030 to -112,783). Bottles of desflurane increased by 726/year (99% CI: 288 to 1,164); costs increased by $171,578/year (99% CI: $136,951 to $206,205). The amount of calculated greenhouse gas emissions released into the atmosphere over this period was 37,000 tonnes of carbon dioxide equivalents, with isoflurane contributing 6%, sevoflurane 17%, and desflurane 77% of this total. In conclusion, isoflurane is no longer being used in the majority of Victorian public hospitals, with sevoflurane and desflurane remaining as the primary volatile agents, utilised respectively at a ratio of 2.2 to 1, and costs at 0.8 to 1.

Adiponectin is associated with bone strength and fracture history in paralyzed men with spinal cord injury.

UNLABELLED: We explored the association between adiponectin levels and bone strength in paralyzed men with spinal cord injury. We found that bone strength was inversely associated with circulating adiponectin levels. Thus, strength estimates and adiponectin levels may improve fracture risk prediction and detection of response to osteogenic therapies following spinal cord injury. PURPOSE: Previous research has demonstrated an inverse relationship between circulating adiponectin and bone mineral density, suggesting that adiponectin may be used as a biomarker for bone health. However, this relationship may reflect indirect effects on bone metabolism via adipose-mediated mechanical pathways rather than the direct effects of adipokines on bone metabolism. Thus, we explored the association between circulating adiponectin levels and bone strength in 27 men with spinal cord injury. METHODS: Plasma adiponectin levels were quantified by ELISA assay. Axial stiffness and maximal load to fracture of the distal femur were quantified via finite element analysis using reconstructed 3D models of volumetric CT scans. We also collected information on timing, location, and cause of previous fractures. RESULTS: Axial stiffness and maximal load were inversely associated with circulating adiponectin levels (R (2) = 0.44, p = 0.01; R (2) = 0.58, p = 0.05) after adjusting for injury duration and lower extremity lean mass. In individuals with post-SCI osteoporotic fractures, distal femur stiffness (p = 0.01) and maximal load (p = 0.005) were lower, and adiponectin was higher (p = 0.04) than those with no fracture history. CONCLUSIONS: Based on these findings, strength estimates may improve fracture risk prediction and detection of response to osteogenic therapies following spinal cord injury. Furthermore, our findings suggest that circulating adiponectin may indeed be a feasible biomarker for bone health and osteoporotic fracture risk in paralyzed individuals with spinal cord injury.

Spontaneous coronary artery dissection in pregnancy requiring emergency caesarean delivery followed by coronary artery bypass grafting.

Spontaneous coronary artery dissection is a rare and often fatal condition of pregnancy. The long-term morbidity is unknown, but a small cohort of patients develop severe ventricular dysfunction as a consequence. We describe a 37-week gestation parturient who presented with cardiogenic shock secondary to spontaneous left main coronary artery dissection. Despite rapid diagnosis, stabilisation with an intra-aortic balloon pump and prompt transfer to a tertiary centre for emergency caesarean delivery and coronary artery bypass grafting, the patient developed a severe postoperative dilated ischaemic cardiomyopathy. There is little information about the long-term outcomes and the specific anaesthesia management of combined emergency caesarean delivery and cardiac surgery in pregnancy for spontaneous coronary artery dissection. Therefore, we outline our multidisciplinary management of this critically ill pregnant woman.