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4. A Hessian for Gaussian Mixture Likelihoods in Nonlinear Least Squares

Author

Korotkine, Vassili, Cohen, Mitchell, and Forbes, James Richard

Subjects
Computer Science - Robotics
Abstract

This paper proposes a novel Hessian approximation for Maximum a Posteriori estimation problems in robotics involving Gaussian mixture likelihoods. Previous approaches manipulate the Gaussian mixture likelihood into a form that allows the problem to be represented as a nonlinear least squares (NLS) problem. The resulting Hessian approximation used within NLS solvers from these approaches neglects certain nonlinearities. The proposed Hessian approximation is derived by setting the Hessians of the Gaussian mixture component errors to zero, which is the same starting point as for the Gauss-Newton Hessian approximation for NLS, and using the chain rule to account for additional nonlinearities. The proposed Hessian approximation results in improved convergence speed and uncertainty characterization for simulated experiments,and similar performance to the state of the art on real-world experiments. A method to maintain compatibility with existing solvers, such as ceres, is also presented. Accompanying software and supplementary material can be found at https://github.com/decargroup/hessian_sum_mixtures., Comment: 8 pages, 2 figures. Accepted to IEEE Robotics and Automation Letters

Published
2024

5. The Invariant Rauch-Tung-Striebel Smoother

Author

van der Laan, Niels, Cohen, Mitchell, Arsenault, Jonathan, and Forbes, James Richard

Subjects
Computer Science - Robotics
Abstract

This paper presents an invariant Rauch-Tung- Striebel (IRTS) smoother applicable to systems with states that are an element of a matrix Lie group. In particular, the extended Rauch-Tung-Striebel (RTS) smoother is adapted to work within a matrix Lie group framework. The main advantage of the invariant RTS (IRTS) smoother is that the linearization of the process and measurement models is independent of the state estimate resulting in state-estimate-independent Jacobians when certain technical requirements are met. A sample problem is considered that involves estimation of the three dimensional pose of a rigid body on SE(3), along with sensor biases. The multiplicative RTS (MRTS) smoother is also reviewed and is used as a direct comparison to the proposed IRTS smoother using experimental data. Both smoothing methods are also compared to invariant and multiplicative versions of the Gauss-Newton approach to solving the batch state estimation problem., Comment: 8 pages, 3 figures, published in Robotics and Automation Letters

Published
2024
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6. Navigation and Control of Unconventional VTOL UAVs in Forward-Flight with Explicit Wind Velocity Estimation

Author

Cohen, Mitchell and Forbes, James Richard

Subjects
Computer Science - Robotics
Abstract

This paper presents a solution for the state estimation and control problems for a class of unconventional vertical takeoff and landing (VTOL) UAVs operating in forward-flight conditions. A tightly-coupled state estimation approach is used to estimate the aircraft navigation states, sensor biases, and the wind velocity. State estimation is done within a matrix Lie group framework using the Invariant Extended Kalman Filter (IEKF), which offers several advantages compared to standard multiplicative EKFs traditionally used in aerospace and robotics problems. An SO(3)- based attitude controller is employed, leading to a single attitude control law without a separate sideslip control loop. A control allocator is used to determine how to use multiple, possibly redundant, actuators to produce the desired control moments. The wind velocity estimates are used in the attitude controller and the control allocator to improve performance. A numerical example is considered using a sample VTOL tailsitter-type UAV with four control surfaces. Monte-Carlo simulations demonstrate robustness of the proposed control and estimation scheme to various initial conditions, noise levels, and flight trajectories., Comment: 8 pages, 7 figures, published in Robotics and Automation Letters

Published
2024
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10. navlie: A Python Package for State Estimation on Lie Groups

Author

Cossette, Charles Champagne, Cohen, Mitchell, Korotkine, Vassili, Bernal, Arturo del Castillo, Shalaby, Mohammed Ayman, and Forbes, James Richard

Subjects
Computer Science - Robotics
Abstract

The ability to rapidly test a variety of algorithms for an arbitrary state estimation task is valuable in the prototyping phase of navigation systems. Lie group theory is now mainstream in the robotics community, and hence estimation prototyping tools should allow state definitions that belong to manifolds. A new package, called navlie, provides a framework that allows a user to model a large class of problems by implementing a set of classes complying with a generic interface. Once accomplished, navlie provides a variety of on-manifold estimation algorithms that can run directly on these classes. The package also provides a built-in library of common models, as well as many useful utilities. The open-source project can be found at https://github.com/decargroup/navlie., Comment: 6 pages, 8 figures, presented at the 2023 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

Published
2023

23. Correction: Demonstrating responsiveness of the pediatric cardiac quality of life inventory in children and adolescents undergoing arrhythmia ablation, heart transplantation, and valve surgery

Author

O’Connor, Amy M., Cassedy, Amy, Cohen, Mitchell, Goldberg, Caren, Lamour, Jacqueline, Mahle, William, Mahony, Lynn, Mussatto, Kathleen, Newburger, Jane, Richmond, Marc E., Shah, Maully, Allen, Kiona, Wolfe, Brian, Wernovsky, Gil, Wray, Jo, and Marino, Bradley S.

Published
2024
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24. Know What You Don't Know: Consistency in Sliding Window Filtering with Unobservable States Applied to Visual-Inertial SLAM (Extended Version)

Author

Lisus, Daniil, Cohen, Mitchell, and Forbes, James Richard

Subjects
Computer Science - Robotics
Abstract

Estimation algorithms, such as the sliding window filter, produce an estimate and uncertainty of desired states. This task becomes challenging when the problem involves unobservable states. In these situations, it is critical for the algorithm to ``know what it doesn't know'', meaning that it must maintain the unobservable states as unobservable during algorithm deployment. This letter presents general requirements for maintaining consistency in sliding window filters involving unobservable states. The value of these requirements for designing navigation solutions is experimentally shown within the context of visual-inertial SLAM making use of IMU preintegration., Comment: Main paper accepted to Robotics and Automation Letters. Main paper has 8 pages, 3 figures. Supplemental materials are 6 pages, 0 figures after the main paper

Published
2022
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29. Letters

Author

Marquardt, Elizabeth, Gallagher, Maggie, Conant, Oliver, Brociner, Ken, Ross, Benjamin, Furstenberg, Frank, Rule, James B., and Cohen, Mitchell

Published
2011
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33. Postinjury platelet aggregation and venous thromboembolism.

Author

Matthay, Zachary, Hellmann, Zane, Nunez-Garcia, Brenda, Fields, Alexander, Neal, Matthew, Berger, Jeffrey, Luttrell-Williams, Elliot, Knudson, M, Cohen, Mitchell, Kornblith, Lucy, Callcut, Rachael, and Cuschieri, Joseph

Subjects
Humans, Venous Thromboembolism, Platelet Aggregation, Thrombin, Platelet Function Tests, Adenosine Diphosphate
Abstract

BACKGROUND: Posttraumatic venous thromboembolism (VTE) remains prevalent in severely injured patients despite chemoprophylaxis. Importantly, although platelets are central to thrombosis, they are not routinely targeted in prevention of posttraumatic VTE. Furthermore, platelets from injured patients show ex vivo evidence of increased activation yet impaired aggregation, consistent with functional exhaustion. However, the relationship of this platelet functional phenotype with development of posttraumatic VTE is unknown. We hypothesized that, following injury, impaired ex vivo platelet aggregation (PA) is associated with the development of posttraumatic VTE. METHODS: We performed a secondary analysis of 133 severely injured patients from a prospective observational study investigating coagulation and inflammation (2011-2019). Platelet aggregation in response to stimulation with adenosine diphosphate (ADP), collagen, and thrombin was measured at presentation (preresuscitation) and 24 hours (postresuscitation). Viscoelastic clot strength and lysis were measured in parallel by thromboelastography. Multivariable regression examined relationships between PA at presentation, 24 hours, and the change (δ) in PA between presentation and 24 hours with development of VTE. RESULTS: The 133 patients were severely injured (median Injury Severity Score, 25), and 14% developed VTE (all >48 hours after admission). At presentation, platelet count and PA were not significantly different between those with and without incident VTE. However, at 24 hours, those who subsequently developed VTE had significantly lower platelet counts (126 × 10 9 /L vs. 164 × 10 9 /L, p = 0.01) and lower PA in response to ADP ( p < 0.05), collagen ( p < 0.05), and thrombin ( p = 0.06). Importantly, the magnitude of decrease in PA (δ) from presentation to 24 hours was independently associated with development of VTE (adjusted odds ratios per 10 aggregation unit decrease: δ-ADP, 1.31 [ p = 0.03]; δ-collagen, 1.36 [ p = 0.01]; δ-thrombin, 1.41 [ p < 0.01]). CONCLUSION: Severely injured patients with decreasing ex vivo measures of PA despite resuscitation have an increased risk of developing VTE. This may have implications for predicting development of VTE and for studying platelet targeted chemoprophylaxis regimens. LEVEL OF EVIDENCE: Prognostic/Epidemiological; Level III.

Published
2022

35. Contributors

Author

Abelson, Jennifer, primary, Aboutanos, Michel B., additional, Abraham, Peter J., additional, Abualruz, Abdul Rahman, additional, Agarwal, Suresh, additional, Agrawal, Devendra K., additional, Alverdy, John C., additional, Aly, Ahmed, additional, Amato, Stas, additional, Anstadt, Michael J., additional, Asensio, Juan A., additional, Avery, Martin, additional, Bailey, Jeffrey A., additional, Barie, Philip S., additional, Becker, Tyson, additional, Beckerman, Daniel, additional, Bedrick, Edward J., additional, Benson, Jamie, additional, Berne, John D., additional, Berry, Cherisse, additional, Berry, Stepheny, additional, Bhat, Sneha G., additional, Bowie, Jason M., additional, Bowyer, Mark W., additional, Bozeman, Matthew C., additional, Bradley, Matthew, additional, Brakenridge, Scott, additional, Brandes, Steven B., additional, Brenner, Megan, additional, Britt, L.D., additional, Brown, Carlos V., additional, Brown, Ian E., additional, Brown, J. Christian, additional, Brown, Tommy, additional, Buckman, Robert F., additional, Burlew, Clay Cothren, additional, Byers, Patricia M., additional, Caban, Kim M., additional, Cancio, Leopoldo C., additional, Cannon, Jeremy W., additional, Cantlie, Shawn M., additional, Carroll, Eben A., additional, Champion, Howard R., additional, Childs, Ed W., additional, Chiu, William C., additional, Christmas, A. Britton, additional, Cioffi, William G., additional, Cocanour, Christine S., additional, Cohen, Mitchell J., additional, Coimbra, Raul, additional, Cook, Alan, additional, Cornell, David L., additional, Cotton, Bryan A., additional, Couture, Daniel E., additional, Cox, Thomas B., additional, Cristancho, Luis Alfonso Bustamante, additional, Croce, Martin A., additional, Croft, Chasen A., additional, Cubano, Miguel A., additional, Dabestani, Parinaz J., additional, Danton, Gary H., additional, Davis, Christopher S., additional, Davis, Kimberly, additional, de Moya, Marc A., additional, Desai, Urmen, additional, Destiné, Henson, additional, Diebel, Lawrence N., additional, Doucet, Jay J., additional, DuBose, Joseph J., additional, Dubov, Wayne E., additional, Duchesne, Juan C., additional, Durham, Rodney M., additional, Durso, Anthony M., additional, Eastridge, Brian, additional, Efron, David T., additional, Efron, Philip A., additional, Elster, Eric, additional, Esposito, Thomas J., additional, Fakhry, Samir M., additional, Feliciano, David V., additional, Fernandez, Carlos, additional, Fernandez-Moure, Joseph S., additional, Fernández, Luis G., additional, Fiorentino, Michele, additional, Firstenberg, Michael S., additional, Flint, Lewis M., additional, Fredericks, Charles J., additional, Fry, Donald E., additional, Galán, Ricardo, additional, Galante, Joseph M., additional, Galvagno, Samuel M., additional, Garcia, Ana Maria, additional, García, Erwin Rodriguez, additional, García-Núñez, Col Luis Manuel, additional, Gentilello, Larry M., additional, Ghanta, Ravi K., additional, Gigena, Alejandro, additional, Gilani, Ramyar, additional, Glance, Laurent G., additional, Goldman, Matthew, additional, Gonzalez, Ernest A., additional, Gonzalez, Richard P., additional, Grabo, Daniel, additional, Gross, Ronald I., additional, Gummadi, Sriharsha, additional, Guerrero, Whitney M., additional, Gunter, Oliver L., additional, Gurney, Jennifer M., additional, Gutiérrez, Jorge A., additional, Hall, Chad, additional, Hauser, Carl J., additional, Henry, Sharon, additional, Hirshberg, Ashen, additional, Holcomb, John B., additional, Hosmer, David, additional, Hoth, J. Jason, additional, Gomez, Tatiana Hoyos, additional, Hoyt, David B., additional, Humphries, Ashley, additional, Iyengar, Rahul, additional, Jawa, Randeep S., additional, Jessie, Elliot, additional, Johannigman, Jay, additional, Aquino Jose, Victor M., additional, Jurkovich, Gregory J., additional, Kalamchi, Louay, additional, Kapil, Aditi M., additional, Karmy-Jones, Riyad, additional, Kasotakis, George, additional, Kelley, Kathryn C., additional, Keskey, Robert, additional, Kessler, John J., additional, Kim, Dennis Y., additional, Kiraly, Laszlo, additional, Kirton, Orlando C., additional, Kotaru, Tharun R., additional, Kunac, Anastasia, additional, Kwolek, Kinga, additional, Lallemand, Michael S., additional, Ledgerwood, Anna M., additional, Lee, Amanda, additional, Leeper, Christine M., additional, Li, Zhongyu, additional, Libby, Matthew, additional, Lim, Robert B., additional, Liveris, Anna, additional, Livingston, David H., additional, Lobb, Jennifer, additional, Loftus, Tyler J., additional, Lucas, Charles E., additional, Luchette, Fred A., additional, Lundeberg, Megan R., additional, Mackersie, Robert C., additional, Mackey, Kevin E., additional, Magnotti, Louis J., additional, Mah, John W., additional, Maldonado, William Sánchez, additional, Malhotra, Ajai K., additional, Malone, Debra L., additional, Marini, Corrado P., additional, Martin, Matthew J., additional, Marttos, Antonio C., additional, Martyak, Michael T., additional, Mathew, Prakash J., additional, Mattox, Kenneth L., additional, Mayberry, John C., additional, Mazzini, Federico N., additional, McNelis, John, additional, Meallet, Mario A., additional, Meerkov, Meir B.L., additional, Meizoso, Jonathan P., additional, Meredith, J. Wayne, additional, Michetti, Christopher P., additional, Miljkovic, Stephanie S., additional, Miller, Keith R., additional, Miller, Preston R., additional, Minei, Joseph P., additional, Mitchell, Frank L., additional, Moas, Victor M., additional, Mohr, Alicia M., additional, Molnar, Joseph A., additional, Moore, Ernest E., additional, Moore, Frederick A., additional, Moutinho, Manuel, additional, Moysidis, Stavros, additional, Munera, Felipe, additional, Naiditch, Jessica A., additional, Napolitano, Lena M., additional, Narayan, Mayur, additional, Nash, Nicholas A., additional, Nicholson, Kristina J., additional, Nicholson, Susannah, additional, Norwood, Scott H., additional, Nunn, Andrew M., additional, O’Shea, Anne, additional, Osler, Turner M., additional, Pachter, H. Leon, additional, Paladino, Lorenzo, additional, Panthaki, Zubin Jal, additional, Parikh, Manish, additional, Pasquale, Michael D., additional, Patel, Purvi P., additional, Peitzman, Andrew B., additional, Peralta, Ruben, additional, Perez-Alonso, Alejandro J., additional, Pestana, Ivo A., additional, Petrone, Patrizio, additional, Pierre, Edgar J., additional, Pilson, Holly, additional, Polk, Travis, additional, Puyana, Juan Carlos, additional, Quintana, David, additional, Rai, Vikrant, additional, Rajasingh, Charlotte, additional, Ranney, Stephen, additional, Reisbig, Mark D., additional, Reiser, Bibiana Jin, additional, Remick, Kyle N., additional, Rhee, Peter, additional, Rich, Norman M., additional, Richardson, J. David, additional, Richart, Charles M., additional, Rivas, Luis A., additional, Robles, Anamaria J., additional, Rodriguez, Aurelio, additional, Rosengart, Matthew, additional, Rosenthal, Martin D., additional, Rotondo, Michael F., additional, Rowe, Vincent L., additional, Rubano, Jerry A., additional, Rubiano, Andrés M., additional, Ruggero, John M., additional, Rushing, Amy, additional, Salim, Ali, additional, Saillant, Noelle Nugent, additional, Sally, Mitchell B., additional, Salsamendi, Jason, additional, Sanford, Arthur P., additional, Savetamal, Alisa, additional, Scalea, Thomas M., additional, Schecter, William, additional, Schipper, Paul H., additional, Schreiber, Martin A., additional, Schroll, Rebecca W., additional, Schulingkamp, Danielle, additional, Schulman, Carl I., additional, Schulz, John T., additional, Shackelford, Stacy A., additional, Shadis, Ryan, additional, Shapiro, Marc J., additional, Shatz, David V., additional, Shiroff, Adam M., additional, Sicard, Gregorio, additional, Sifri, Ziad C., additional, Sing, Ronald F., additional, Sisley, Amy, additional, Smith, Brian P., additional, Smith, R. Stephen, additional, Singares, Eduardo Smith, additional, Sola, Richard, additional, Spain, David A., additional, Spencer, Audrey L., additional, Stavas, Joseph, additional, Stawicki, Stanislaw P., additional, Stein, Deborah M., additional, Stewart, Nakosi, additional, Stirparo, Joseph J., additional, Strong, Bethany L., additional, Sukumar, Mithran S., additional, Tadlock, Matthew D., additional, Taylor, John R., additional, Thaller, Seth R., additional, Thomas, Bradley W., additional, Thompson, Ashley M., additional, Tieu, Brandon H., additional, Tillou, Areti, additional, Tinkoff, Glen H., additional, Tisherman, Samuel A., additional, Todd, S. Rob, additional, Tominaga, Gail T., additional, Trammell, Amy Phillips, additional, Trunkey, Donald D., additional, Tuggle, David, additional, Upchurch, Gilbert R., additional, Van, Philbert, additional, VanDerHeyden, Nicole, additional, Vanzant, Erin L., additional, Wall, Matthew J., additional, Wenzl, Florian A., additional, Whitlow, Christopher T., additional, Wiegand, Lucas R., additional, Williams, Timothy K., additional, Wilson, Jonathan L., additional, Yeh, D. Dante, additional, Youngblood, Charles F., additional, and Zhang, Wei, additional

Published
2024
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37. Patterns of Electrocardiographic Abnormalities in Children with Hypertrophic Cardiomyopathy

Author

Marshall, Mayme, Malik, Aneeq, Shah, Maully, Fish, Frank A., Etheridge, Susan P., Aziz, Peter F., Russell, Mark W., Tisma, Svjetlana, Pflaumer, Andreas, Sreeram, Narayanswami, Kubus, Peter, Law, Ian H., Kantoch, Michal J., Kertesz, Naomi J., Strieper, Margaret, Erickson, Christopher C., Moore, Jeremy P., Nakano, Stephanie J., Singh, Harinder R., Chang, Philip, Cohen, Mitchell, Fournier, Anne, Ilina, Maria V., Zimmermann, Frank, Horndasch, Michaela, Li, Walter, Batra, Anjan S., Liberman, Leonardo, Hamilton, Robert, Janson, Christopher M., Sanatani, Shubhayan, Zeltser, Ilana, McDaniel, George, Blaufox, Andrew D., Garnreiter, Jason M., and Balaji, Seshadri

Published
2023
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40. Smoking primes the metabolomic response in trauma

Author

Gallagher, Lauren T., Erickson, Christopher, DʼAlessandro, Angelo, Schaid, Terry, Thielen, Otto, Hallas, William, Mitra, Sanchayita, Stafford, Preston, Moore, Ernest E., Silliman, Christopher C., Calfee, Carolyn S., and Cohen, Mitchell J.

Published
2024
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43. Cigarette Smoke Exposure and Acute Respiratory Distress Syndrome in Sepsis: Epidemiology, Clinical Features, and Biologic Markers.

Author

Moazed, Farzad, Hendrickson, Carolyn, Jauregui, Alejandra, Gotts, Jeffrey, Conroy, Amanda, Delucchi, Kevin, Zhuo, Hanjing, Arambulo, Mikhaela, Vessel, Kathryn, Ke, Serena, Deiss, Thomas, Ni, Amy, Leligdowicz, Aleksandra, Abbott, Jason, Cohen, Mitchell J, Sinha, Pratik, Gomez, Antonio, Kangelaris, Kirsten, Kornblith, Lucy, Matthay, Michael, Benowitz, Neal, Liu, Kathleen, and Calfee, Carolyn S

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Sepsis, Hematology, Prevention, Lung, Clinical Research, Rare Diseases, Tobacco Smoke and Health, Tobacco, Infectious Diseases, Acute Respiratory Distress Syndrome, Detection, screening and diagnosis, Aetiology, 4.1 Discovery and preclinical testing of markers and technologies, 2.1 Biological and endogenous factors, Respiratory, Inflammatory and immune system, Cancer, Good Health and Well Being, Biomarkers, Cigarette Smoking, Humans, Lung Injury, Prospective Studies, Respiratory Distress Syndrome, Tobacco Smoke Pollution, ARDS, cigarette smoking, biomarkers, Medical and Health Sciences, Respiratory System, Cardiovascular medicine and haematology, Clinical sciences
Abstract

Rationale: Cigarette smoke exposure is associated with an increased risk of developing acute respiratory distress syndrome (ARDS) in trauma, transfusion, and nonpulmonary sepsis. It is unknown whether this relationship exists in the general sepsis population. Furthermore, it is unknown if patients with ARDS have differences in underlying biology based on smoking status. Objectives: To assess the relationship between cigarette smoke exposure and ARDS in sepsis and identify tobacco-related biomarkers of lung injury. Methods: We studied a prospective cohort of 592 patients with sepsis from 2009 to 2017. Plasma cotinine and urine NNAL [urine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol] were measured to categorize smoking status. Plasma biomarkers of inflammation and lung injury were measured, including in a smaller cohort of trauma patients with ARDS to increase generalizability. Measurements and Main Results: Passive and active smoking were associated with increased odds of developing ARDS in patients with sepsis. Among patients with sepsis and ARDS, active cigarette smokers were younger and had lower severity of illness than nonsmokers. Patients with ARDS with cigarette smoke exposure had lower plasma levels of IL-8 (P = 0.01) and sTNFR-1 (soluble tumor necrosis factor 1; P = 0.01) compared with those without exposure. Similar biomarker patterns were observed in blunt trauma patients with ARDS. Conclusions: Passive and active smoking are associated with an increased risk of developing ARDS in patients with pulmonary and nonpulmonary sepsis. Among patients with ARDS, those with cigarette smoke exposure have less systemic inflammation, while active smokers also have lower severity of illness compared with nonsmokers, suggesting that smoking contributes to biological heterogeneity in ARDS.

Published
2022

44. Inhalation Injury is Associated with Endotheliopathy and Abnormal Fibrinolytic Phenotypes in Burn Patients: A Cohort Study

Author

Keyloun, John W, Le, Tuan D, Brummel-Ziedins, Kathleen E, Mclawhorn, Melissa M, Bravo, Maria C, Orfeo, Thomas, Johnson, Laura S, Moffatt, Lauren T, Pusateri, Anthony E, Shupp, Jeffrey W, McLawhorn, Melissa M, Callcut, Rachael A, Cohen, Mitchell J, Petzold, Linda R, Varner, Jeffrey D, Bravo, Maria Cristina, Freeman, Kalev, Mann, Kenneth G, Gautam, Aarti, Hammamieh, Rasha, and Jett, Marti

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Hematology, Physical Injury - Accidents and Adverse Effects, Clinical Research, Good Health and Well Being, Burns, Cohort Studies, Female, Humans, Male, Phenotype, Retrospective Studies, Thrombelastography, SYSCOT Study Group, Emergency & Critical Care Medicine, Clinical sciences, Allied health and rehabilitation science, Nursing
Abstract

Burn injury is associated with endothelial dysfunction and coagulopathy and concomitant inhalation injury (IHI) increases morbidity and mortality. The aim of this work is to identify associations between IHI, coagulation homeostasis, vascular endothelium, and clinical outcomes in burn patients. One hundred and twelve patients presenting to a regional burn center were included in this retrospective cohort study. Whole blood was collected at set intervals from admission through 24 hours and underwent viscoelastic assay with rapid thromboelastography (rTEG). Syndecan-1 (SDC-1) on admission was quantified by ELISA. Patients were grouped by the presence (n = 28) or absence (n = 84) of concomitant IHI and rTEG parameters, fibrinolytic phenotypes, SDC-1, and clinical outcomes were compared. Of the 112 thermally injured patients, 28 (25%) had IHI. Most patients were male (68.8%) with a median age of 40 (interquartile range, 29-57) years. Patients with IHI had higher overall mortality (42.68% vs 8.3%; P < .0001). rTEG LY30 was lower in patients with IHI at hours 4 and 12 (P < .05). There was a pattern of increased abnormal fibrinolytic phenotypes among IHI patients. There was a greater proportion of IHI patients with endotheliopathy (SDC-1 > 34 ng/ml) (64.7% vs 26.4%; P = .008). There was a pattern of increased mortality among patients with IHI and endotheliopathy (0% vs 72.7%; P = .004). Significant differences between patients with and without IHI were found in measures assessing fibrinolytic potential and endotheliopathy. Mortality was associated with abnormal fibrinolysis, endotheliopathy, and IHI. However, the extent to which IHI-associated dysfunction is independent of TBSA burn size remains to be elucidated.

Published
2022

45. Finite-Horizon LQR Control of Quadrotors on $SE_2(3)$

Author

Cohen, Mitchell R., Abdulrahim, Khairi, and Forbes, James Richard

Subjects
Computer Science - Robotics
Abstract

This paper considers optimal control of a quadrotor unmanned aerial vehicles (UAV) using the discrete-time, finite-horizon, linear quadratic regulator (LQR). The state of a quadrotor UAV is represented as an element of the matrix Lie group of double direct isometries, $SE_2(3)$. The nonlinear system is linearized using a left-invariant error about a reference trajectory, leading to an optimal gain sequence that can be calculated offline. The reference trajectory is calculated using the differentially flat properties of the quadrotor. Monte-Carlo simulations demonstrate robustness of the proposed control scheme to parametric uncertainty, state-estimation error, and initial error. Additionally, when compared to an LQR controller that uses a conventional error definition, the proposed controller demonstrates better performance when initial errors are large., Comment: Published in IEEE Robotics and Automation Letters and presented at the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

Published
2021
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46. Associations of longitudinal D-Dimer and Factor II on early trauma survival risk

Author

Jiang, Richard M, Pourzanjani, Arya A, Cohen, Mitchell J, and Petzold, Linda

Subjects
Mathematical Sciences, Statistics, Clinical Research, Good Health and Well Being, Adolescent, Adult, Aged, Aged, 80 and over, Bayes Theorem, Female, Fibrin Fibrinogen Degradation Products, Humans, Male, Middle Aged, Prothrombin, Retrospective Studies, Survival Analysis, Wounds and Injuries, Young Adult, Early trauma survival risk, Longitudinal models, Joint models, Clinical panel data, D-Dimer, Factor II, Biological Sciences, Information and Computing Sciences, Bioinformatics, Biological sciences, Information and computing sciences, Mathematical sciences
Abstract

BackgroundTrauma-induced coagulopathy (TIC) is a disorder that occurs in one-third of severely injured trauma patients, manifesting as increased bleeding and a 4X risk of mortality. Understanding the mechanisms driving TIC, clinical risk factors are essential to mitigating this coagulopathic bleeding and is therefore essential for saving lives. In this retrospective, single hospital study of 891 trauma patients, we investigate and quantify how two prominently described phenotypes of TIC, consumptive coagulopathy and hyperfibrinolysis, affect survival odds in the first 25 h, when deaths from TIC are most prevalent.MethodsWe employ a joint survival model to estimate the longitudinal trajectories of the protein Factor II (% activity) and the log of the protein fragment D-Dimer ([Formula: see text]g/ml), representative biomarkers of consumptive coagulopathy and hyperfibrinolysis respectively, and tie them together with patient outcomes. Joint models have recently gained popularity in medical studies due to the necessity to simultaneously track continuously measured biomarkers as a disease evolves, as well as to associate them with patient outcomes. In this work, we estimate and analyze our joint model using Bayesian methods to obtain uncertainties and distributions over associations and trajectories.ResultsWe find that a unit increase in log D-Dimer increases the risk of mortality by 2.22 [1.57, 3.28] fold while a unit increase in Factor II only marginally decreases the risk of mortality by 0.94 [0.91,0.96] fold. This suggests that, while managing consumptive coagulopathy and hyperfibrinolysis both seem to affect survival odds, the effect of hyperfibrinolysis is much greater and more sensitive. Furthermore, we find that the longitudinal trajectories, controlling for many fixed covariates, trend differently for different patients. Thus, a more personalized approach is necessary when considering treatment and risk prediction under these phenotypes.ConclusionThis study reinforces the finding that hyperfibrinolysis is linked with poor patient outcomes regardless of factor consumption levels. Furthermore, it quantifies the degree to which measured D-Dimer levels correlate with increased risk. The single hospital, retrospective nature can be understood to specify the results to this particular hospital's patients and protocol in treating trauma patients. Expanding to a multi-hospital setting would result in better estimates about the underlying nature of consumptive coagulopathy and hyperfibrinolysis with survival, regardless of protocol. Individual trajectories obtained with these estimates can be used to provide personalized dynamic risk prediction when making decisions regarding management of blood factors.

Published
2021

50. Acute respiratory distress syndrome, acute kidney injury, and mortality after trauma are associated with increased circulation of syndecan-1, soluble thrombomodulin, and receptor for advanced glycation end products

Author

Dixon, Alexandra, Kenny, James E., Buzzard, Lydia, Holcomb, John, Bulger, Eileen, Wade, Charles, Fabian, Timothy, Schreiber, Martin, Holcomb, John B., Wade, Charles E., del Junco, Deborah J., Fox, Erin E., Matijevic, Nena, Podbielski, Jeanette M., Beeler, Angela M., Tilley, Barbara C., Baraniuk, Sarah, DeSantis, Stacia M., Zhu, Hongjian, Nixon, Joshua, Seay, Roann, Appana, Savitri N., Yang, Hui, Gonzalez, Michael O., Baer, Lisa, Wang, Yao-Wei Willa, Hula, Brittany S., Espino, Elena, Nguyen, An, Pawelczyk, Nicholas, Arora-Nutall, Kisha D., Sharma, Rishika, Cardenas, Jessica C., Rahbar, Elaheh, Burnett, Tyrone, Jr, Clark, David, van Belle, Gerald, May, Susanne, Leroux, Brian, Hoyt, David, Powell, Judy, Sheehan, Kellie, Hubbard, Alan, Arkin, Adam P., Hess, John R., Callum, Jeannie L., Pittet, Jean-Francois, Miller, Christopher N., Cotton, Bryan A., Vincent, Laura, Welch, Timothy, Poole, Tiffany, Pivalizza, Evan G., Gumbert, Sam D., Bai, Yu, McCarthy, James J., Noland, Amy, Hobbs, Rhonda, Bulger, Eileen M., Klotz, Patricia, Cattin, Lindsay, Warner, Keir J., Wilson, Angela, Boman, David, White, Nathan, Grabinsky, Andreas, Daniel-Johnson, Jennifer A., Cohen, Mitchell Jay, Callcut, Rachael A., Nelson, Mary, Redick, Brittney, Conroy, Amanda, Steurer, Marc P., Maxim, Preston C., Fiebig, Eberhard, Moore, Joanne, Mallari, Eireen, Muskat, Peter, Johannigman, Jay A., Robinson, Bryce R. H., Branson, Richard D., Gomaa, Dina, Barczak, Christopher, Bennett, Suzanne, Carey, Patricia M., Hancock, Helen, Rodriguez, Carolina, Inaba, Kenji, Zhu, Jay G., Wong, Monica D., Menchine, Michael, Katzberg, Kelly, Henderson, Sean O., McKeever, Rodney, Shulman, Ira A., Nelson, Janice M., Tuma, Christopher W., Matsushita, Cheryl Y., Scalea, Thomas M., Stein, Deborah M., Shaffer, Cynthia K., Wade, Christine, Herrera, Anthony V., Kallam, Seeta, Wade, Sarah E., Galvagno, Samuel M., Jr, Fontaine, Magali J., Hunt, Janice M., Cooke, Rhonda K., Fabian, Timothy C., Weinberg, Jordan A., Croce, Martin A., Wilson, Suzanne, Panzer-Baggett, Stephanie, Waddle-Smith, Lynda, Flax, Sherri, Brasel, Karen J., Walsh, Pamela, Milia, David, Nelson, Allia, Kaslow, Olga, Aufderheide, Tom P., Gottschall, Jerome L., Carpenter, Erica, OʼKeeffe, Terence, Rokowski, Laurel L., Denninghoff, Kurt R., Redford, Daniel T., Novak, Deborah J., Knoll, Susan, Kerby, Jeffrey D., Bosarge, Patrick L., Pierce, Albert T., Williams, Carolyn R., Stephens, Shannon W., Wang, Henry E., Marques, Marisa B., Schreiber, Martin A., Watters, Jennifer M., Underwood, Samantha J., Groat, Tahnee, Newgard, Craig, Merkel, Matthias, Scanlan, Richard M., Miller, Beth, Rizoli, Sandro, Tien, Homer, Nascimento, Barto, Trpcic, Sandy, Sobrian-Couroux, Skeeta, Reis, Marciano, Pérez, Adic, Belo, Susan E., Merkley, Lisa, and Colavecchia, Connie

Published
2024
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