My research develops and applies statistical, computational, and AI-enabled methods to address clinically important questions in perioperative medicine, trauma recovery, and complex health data analysis. Across projects, I work closely with clinicians, trainees, and interdisciplinary collaborators to build research programs that are methodologically rigorous, practically useful, and increasingly supported by reproducible data science and AI workflows.
I view Research and Portfolio as complementary pages: this page summarizes the main scientific directions and representative work, while the Portfolio page highlights current systems-building efforts such as AI-assisted clinical summarization and prediction pipelines.
Research Areas
Perioperative Medicine
Patient-centered and data-informed perioperative care
I study perioperative risk factors, treatment effects, gastric ultrasound, fluid status, and AI-assisted decision support tools designed to improve preoperative and intraoperative care.
Trauma Recovery
Posttraumatic pain, neuropsychiatric outcomes, and biomarkers
I develop prediction tools, identify clinically meaningful subgroups, and investigate wearable, language, and behavioral biomarkers for heterogeneous posttraumatic outcomes.
Methodology
Statistical modeling for high-dimensional and longitudinal data
My methodological work spans latent variable models, heterogeneous treatment effects, hidden Markov models, and computational approaches for complex longitudinal health data.
Selected Work By Area
Perioperative care and clinical decision support
Collaborators
- Wrobel JR, Magin JC, Koyama Y, Sanders DG, Pillai M, An X, Grant SA, Doyal AS. Developing a method for ultrasound estimation of gastric volume in patients with previous gastric sleeve. Reg Anesth Pain Med. 2025.
- Jacqueline A. Quinn, Kevin M. Welch, Erina Fujino, Carlos A. Jimenez Rosado, Xinming An, Jay W. Schoenherr, Lindsey N. Gouker. Perioperative glucagon-like peptide-1 receptor agonist use and retained gastric contents: A retrospective analysis of patients undergoing elective upper endoscopy. Journal of Clinical Anesthesia. 2025.
- Magin JC, Wrobel JR, An X, Acton J, Doyal A, Jia S, Krakowski JC, Schoenherr J, Serrano R, Flynn D, McLean D, Grant SA. Venous Excess Ultrasound (VExUS) grading to assess perioperative fluid status for noncardiac surgeries: a prospective observational pilot study. POCUS J. 2023.
- Smeltz AM, Farber MA, Parodi FE, An X, Kirsch RJ, Hipp JS, Kumar PA, Arora H. Comparison of landmark-guided versus fluoroscopy-guided cerebrospinal fluid drain-related complications after aortic repairs. J Cardiothorac Vasc Anesth. 2023.
Posttraumatic outcomes and recovery
Collaborators
Sarah Linnstaedt, Lauriane Guichard, Sam McLean, and Chiyoung Lee.
- Vizer L, Pierce J, Ji Y, Bucher MA, Liu M, Ungar L, Giorgi S, Xing Z, House SL, Beaudoin FL, Stevens JS, Neylan TC, Clifford GD, Jovanovic T, Linnstaedt SD, Zeng D, Germine LT, Bollen KA, Rauch SL, Haran JP, Storrow AB, Lewandowski C, Musey PI Jr, Hendry PL, Sheikh S, Jones CW, Punches BE, Hudak LA, Pascual JL, Seamon MJ, Harris E, Pearson C, Peak DA, Merchant RC, Domeier RM, O’Neil BJ, Sergot P, Sanchez LD, Bruce SE, Harte SE, Kessler RC, Koenen KC, McLean SA, An X. Smartphone language features may help identify adverse post-traumatic neuropsychiatric sequelae and their trajectories. NPP Digit Psychiatry Neurosci. 2025.
- Guichard L, An X, Neylan TC, Clifford GD, Li Q, Ji Y, Macchio L, Baker J, Beaudoin FL, Jovanovic T, Linnstaedt SD, Germine LT, Bollen KA, Rauch SL, Haran JP, Storrow AB, Lewandowski C, Musey PI Jr, Hendry PL, Sheikh S, Jones CW, Punches BE, Swor RA, Gentile NT, Pascual JL, Seamon MJ, Datner EM, Pearson C, Peak DA, Merchant RC, Domeier RM, Rathlev NK, O’Neil BJ, Sergot P, Sanchez LD, Bruce SE, Sheridan JF, Harte SE, Ressler KJ, Koenen KC, Kessler RC, McLean SA. Heart rate variability wrist-wearable biomarkers identify adverse posttraumatic neuropsychiatric sequelae after traumatic stress exposure. Psychiatry Res. 2024.
- Lee C, House SL, Beaudoin FL, Neylan TC, Clifford GD, Linnstaedt SD, Germine LT, Rauch SL, Haran JP, Storrow AB, Lewandowski C, Musey PI Jr, Hendry PL, Sheikh S, Punches BE, Swor RA, Hudak LA, Pascual JL, Seamon MJ, Harris E, Pearson C, Peak DA, Domeier RM, Rathlev NK, O’Neil BJ, Sergot P, Sanchez LD, Bruce SE, Sheridan JF, Harte SE, Koenen KC, Kessler RC, McLean SA, Yang Q, An X. Understanding onset, dynamic transitions, and associated inequality risk factors for adverse posttraumatic neuropsychiatric sequelae after trauma exposure. Psychiatr Res Clin Pract. 2024.
- Jones CW, An X, Ji Y, Liu M, Zeng D, House SL, Beaudoin FL, Stevens JS, Neylan TC, Clifford GD, Jovanovic T, Linnstaedt SD, Germine LT, Bollen KA, Rauch SL, Haran JP, Storrow AB, Lewandowski C, Musey PI Jr, Hendry PL, Sheikh S, Punches BE, Lyons MS, Kurz MC, Swor RA, McGrath ME, Hudak LA, Pascual JL, Seamon MJ, Datner EM, Harris E, Chang AM, Pearson C, Peak DA, Merchant RC, Domeier RM, Rathlev NK, O’Neil BJ, Sergot P, Sanchez LD, Bruce SE, Miller MW, Pietrzak RH, Joormann J, Barch DM, Pizzagalli DA, Sheridan JF, Smoller JW, Harte SE, Elliott JM, Koenen KC, Ressler KJ, Kessler RC, McLean SA. Derivation and validation of a brief ED-based prediction tool for posttraumatic stress after motor vehicle collision. Ann Emerg Med. 2022.
Statistical methodology and high-dimensional data analysis
- Ge L, An X, Zeng D, McLean S, Kessler R, Song R. Continuous-time hidden Markov factor model for mobile health data: application to adverse posttraumatic neuropsychiatric sequelae. IEEE J Biomed Health Inform. 2025.
- Watson RA, Cai H, An X, McLean S, Song R. On heterogeneous treatment effects in heterogeneous causal graphs. ICML 2023.
- An X, Yang Q, Bentler PM. A latent factor linear mixed model for high-dimensional longitudinal data analysis. Statistics in Medicine. 2013.
- An X, Bentler PM. Extended mixture factor analysis model with covariates for mixed binary and continuous responses. Statistics in Medicine. 2011.
- An X, Bentler PM. Efficient direct sampling MCEM algorithm for latent variable models with binary responses. Computational Statistics & Data Analysis. 2012.
For project-level systems work, demos, and current AI-enabled pipelines, see the Portfolio page. For a broader academic record and external publication profiles, see CV.