BACKGROUND: Pulmonary complications, including infections, are highly prevalent in patients after hematopoietic cell transplantation with chronic graft-vs-host disease. These comorbid diseases can make the diagnosis of early lung graft-vs-host disease (bronchiolitis obliterans syndrome) challenging. A quantitative method to differentiate among these pulmonary diseases can address diagnostic challenges and facilitate earlier and more targeted therapy. STUDY DESIGN AND METHODS:We conducted a single-center study of 66 patients with CT chest scans analyzed with a quantitative imaging tool known as parametric response mapping. Parametric response mapping results were correlated with pulmonary function tests and clinical characteristics. Five parametric response mapping metrics were applied to K-means clustering and support vector machine models to distinguish among posttransplantation lung complications solely from quantitative output.RESULTS: Compared with parametric response mapping, spirometry showed a moderate correlation with radiographic air trapping, and total lung capacity and residual volume showed a strong correlation with radiographic lung volumes. K-means clustering analysis distinguished four unique clusters. Clusters 2 and 3 represented obstructive physiology (encompassing 81% of patients with bronchiolitis obliterans syndrome) in increasing severity (percentage air trapping 15.6% and 43.0%, respectively). Cluster 1 was dominated by normal lung, and cluster 4 was characterized by patients with parenchymal opacities. A support vector machine algorithm differentiated bronchiolitis obliterans syndrome with a specificity of 88%, sensitivity of 83%, accuracy of 86%, and an area under the receiver operating characteristic curve of 0.85. INTERPRETATION:Our machine learning models offer a quantitative approach for the identification of bronchiolitis obliterans syndrome vs other lung diseases, including late pulmonary complications after hematopoietic cell transplantation.

Mechanical circulatory support (MCS) has made rapid progress over the last three decades. This was driven by the need to develop acute and chronic circulatory support as well as by the limited organ availability for heart transplantation. The growth of MCS was also driven by the use of extracorporeal membrane oxygenation (ECMO) after the worldwide H1N1 influenza outbreak of 2009. The majority of mechanical pumps (ECMO and left ventricular assist devices) are currently based on continuous flow pump design. It is interesting to note that in the current era, we have reverted from the mammalian pulsatile heart back to the continuous flow pumps seen in our simple multicellular ancestors. This review will highlight key physiological concepts of the assisted circulation from its effects on cardiac dynamics to principles of cardiopulmonary fitness. We will also examine the physiological principles of the ECMO-assisted circulation, anticoagulation and the hemocompatibility challenges that arise when the blood is exposed to a foreign mechanical circuit. Finally, we conclude with a perspective on smart design for future development of devices used for MCS.

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The projected prevalence of obesity in the US is 50% by 2030.1 Little data exists on resident physician obesity management in their primary care clinics.2 We aimed to explore internal medicine (IM) resident comfort, knowledge, and treatment practice of obesity in primary care. IM residents at one academic medical center (N=125), at 5 primary care sites were anonymously surveyed about knowledge, comfort, and practice behaviors around obesity management. In this exploratory analysis, respondents self-reported comfort with lifestyle counselling and weight management medication (WMM) prescription on 4-point Likert scales; scores were combined into an overall Comfort Score (CS). Correlation analysis (Pearson’s correlation) compared CS with the following Clinical Actions: referral to lifestyle specialists, lifestyle counseling, WMM prescription, and bariatric surgery referral. The response rate was 70/125 (56%). Most residents (91%) reported discomfort with prescribing WMMs and most (84%) had never prescribed one. While most residents (81%) were “comfortable” or “somewhat comfortable” with lifestyle counseling, only 33% reported consistently providing it. Of the 31% of residents that correctly identified indications for bariatric surgery, only 9% reported referring patients they considered appropriate for surgery. Notably, a higher CS was significantly correlated with more frequent bariatric surgery referrals (r = 0.29; p = 0.015), lifestyle counselling (r = 0.33; p = 0.004), WMM prescription (r = 0.32; p=0.006), and lifestyle specialist referral (r = 0.25; p = 0.035). Reported barriers to lifestyle counseling were lack of time (93%), poor familiarity with resources (50%), and lack of training in motivational interviewing (36%). Barriers to WMM prescription were unfamiliarity with the medications (84%) and side effect concerns (61%). Finally, 90% desired more training in pharmacotherapy, and 77% wanted more information on referral processes for surgical and medical interventions. Most residents surveyed do not feel adequately prepared to provide evidence-based management of obesity via lifestyle changes counseling, WMM prescription, or specialty care referral. Comfort and knowledge of system processes/resources and WMMs are critical to resident management of obesity. These are potential targets for educational intervention in residency curricula that may improve care for patients with obesity. Citations: 1. Ward ZJ, Bleich SN, Cradock AL, et al. Projected U.S. State-Level Prevalence of Adult Obesity and Severe Obesity. N Engl J Med. 2019;381(25):2440-2450. doi:10.1056/NEJMsa19093012. Huang J, Yu H, Marin E, Brock S, Carden D, Davis T. Physicians’ Weight Loss Counseling in Two Public Hospital Primary Care Clinics. Acad Med. 2004. doi:10.1097/00001888-200402000-00012