About

Aalok Kacha, MD PhD, is an Associate Professor of Anesthesia and Critical Care as well as Surgery at the University of Chicago. His clinical interests include anesthesia, with a focus on caring for transplant patients and managing intraoperative cardiac events. Dr. Kacha's research encompasses various aspects of anesthesiology and critical care, including intraoperative ventilation strategies, management of intraoperative cardiac arrest, and postoperative infection risk in transplant recipients. His work has contributed to understanding perioperative fluid strategies, protective ventilation techniques, and the management of complex transplant cases. He holds a PhD in Immunology and has completed his MD, internship, residency, and fellowship at the University of Chicago, establishing a strong foundation in both clinical practice and research in critical care medicine.

Research topics

• Medicine
• Surgery
• Internal medicine
• Anesthesia
• Immunology
• Microbiology
• Gastroenterology
• Family medicine
• Endocrinology
• Intensive care medicine
• Bioinformatics
• Biology
• Nursing

Selected publications

• Caring for the Transplant Patient for Non-transplant Anesthesia

  International Anesthesiology Clinics · 2025-05-22

  articleSenior author
  PublisherDOI

• Microbiome compositions and fecal metabolite concentrations predict post-operative infection in liver transplant recipients

  medRxiv · 2023-02-18

  preprintOpen accessSenior author

  ABSTRACT Background Liver transplantation (LT) is associated with postoperative infections caused by antibiotic-resistant bacterial pathogens that reside in the intestine. An intact intestinal microbiome suppresses expansion of enteric pathogens, however patients with severe liver disease often have reduced microbiome diversity and increased density of antibiotic-resistant Enterococcus and Enterobacterales species. (1–4) Experimental models have demonstrated that metabolites produced by the intestinal microbiome, including short chain fatty acids (SCFAs), secondary bile acids and indole compounds, enhance host epithelial and immune defenses against enteric pathogens.(5–10) Microbiome derived metabolites likely contribute to resistance against infectious diseases in LT patients, however, this remains uninvestigated. Methods We prospectively enrolled 107 liver transplant candidates and determined peri-transplant fecal microbiome compositions including relative and absolute fecal metabolite concentrations. Results Fecal microbiomes in LT recipients ranged from highly diverse to complete loss of diversity resulting in expansion of Enterococcus and/or Enterobacterales species that were associated with postoperative infection. Gas chromatographic (GC-) and liquid chromatographic (LC-) Mass spectrometric analyses revealed decreased concentrations of SCFAs, secondary bile acids, and indole compounds in fecal samples with low microbiome diversity and associated expansion of Enterococcus and Enterobacterales populations. Conclusion Fecal metabolite abundances accurately predicted LT patients with reduced microbial diversity and those who developed postoperative infection.

  PublisherOA PDFDOI

• Fecal metabolite profiling identifies liver transplant recipients at risk for postoperative infection

  Cell Host & Microbe · 2023 · 31 citations

  Senior authorCorresponding
  • Biology
  • Immunology
  • Microbiology
  PublisherDOI

• Management of Intraoperative Cardiac Arrest

  Anesthesiology Clinics · 2023-03-01 · 2 citations

  review1st authorCorresponding
  PublisherDOI

• 287. Fecal Microbiome and Microbial Metabolites Predict Postoperative <i>Enteroccoccus</i> and <i>Enterobacterales</i> Infections in Liver Transplant

  Open Forum Infectious Diseases · 2023-11-27

  articleOpen accessSenior author

  Abstract Background Liver transplantation (LT) is associated with postoperative infections caused by antibiotic-resistant bacterial pathogens that reside in the intestine. An intact intestinal microbiome suppresses expansion of enteric pathogens, however patients with severe liver disease often have reduced microbiome diversity and increased density of antibiotic-resistant Enterococcus and Enterobacterales species. Experimental models have demonstrated that metabolites produced by the intestinal microbiome, including short chain fatty acids (SCFAs), secondary bile acids and indole compounds, enhance host epithelial and immune defenses against enteric pathogens. Microbiome derived metabolites likely contribute to resistance against infectious diseases in LT patients, however, this remains uninvestigated. Graphical Abstract Methods We prospectively enrolled 158 liver transplant candidates and determined peri-transplant fecal microbiome compositions including relative and absolute fecal metabolite concentrations. We then used microbiome composition characteristics and metabolite profiles to predict postoperative bacterial infection. Enrollment Results Fecal microbiomes in LT recipients ranged from highly diverse to complete loss of diversity resulting in expansion of Enterococcus and/or Enterobacterales species that were associated with postoperative infection. Gas chromatographic (GC-) and liquid chromatographic (LC-) Mass spectrometric analyses revealed decreased concentrations of SCFAs, secondary bile acids, and indole compounds in fecal samples with low microbiome diversity and associated expansion of Enterococcus and Enterobacterales populations. Enterococcus and Enterobacterales expansion at 20% and 2.5% respectively reliably predicted postoperative infection. Reduced short chain fatty acids, secondary bile acids, and indole metabolites predicted postoperative bacterial infection as well as Enterococcus and Enterobacterales expansion. Microbiome Compositions of LT recipients vary widely (A) Fecal microbiome composition plots of liver transplant (LT) patients and healthy donors (HD) vertically organized by relative abundance and color coded by taxa. Individual samples were ordered horizontally by Shannon diversity. (B) taxUMAP1 plot of taxonomic composition, HD are denoted as triangles. Samples are color coded by the most abundant taxon and size determined by the relative abundance of that taxon. (C-E) Comparison of Alpha diversity between LT diversity groups and between high diversity and HD using (C) Inverse Simpson, (D) Shannon, and (E) Richness. (F-J) Comparison of relative abundance of select taxa between LT diversity groups and HD. (F) Lachnospiraceae; (G) Enterococcus; (H) Enterobacterales; (I) Bacteroidetes; (J) Oscilospiraceae. Significance tested by Kruskal-Wallis test *p≤ 0.05 **p≤0.01 ***p≤0.001 ****p≤0.0001 Qualitatively measured microbiome derived fecal metabolites vare widely among LT recipients Individual metabolite abundances represented on a colorimetric heat map by log2 fold change from the mean between samples. Red indicating increased abundance; blue indicating reduced abundance. Significance was measured between LT groups using the Kurskal-Wallis test and denoted on a colorimetric scale where green represents lower p-values, adjusted for multiple comparisons. HD were included for visual comparison. Add. Compounds include kynurenine pathway and phenolic aromatics. Abbreviations: 1°-Primary; 2°-Secondary; Add.-Additional; 3-Oxo-D-Or-3-Oxocheno.-1-Oxo-Deoxycholic or 3-Oxochenodeoxycholic acid, which could not be completely discriminated chromatographically and are included together. Enterococcus and Enterobacterales expansion microbiome predicts postoperative infection (A) Fecal microbiome composition plots color coded by taxon. Plots are categorized by presence of bacterial infection and ordered by descending relative abundance of Enterococcus. Colored tiles indicate an infection caused by the denoted organism associated with that stool sample. For taxonomic color palate refer to Figure 1. (B) Receiver operator curve using Enterococcus abundance to predict Enterococcus infection. Cut point determined by Youden Index to optimize both sensitivity and specificity. 95% Confidence intervals for Accuracy (0.74-0.91), Specificity (59-94%), and Sensitivity (65-100%). (C) Fecal microbiome composition plots organized by relative abundance of Enterobacterales. (D) Receiver operator curve using Enterobacterales abundance to predict Enterobacterales infection. 95% Confidence intervals Accuracy (0.82-0.96), Specificity (72-94%), and Sensitivity (100-100%). Abbreviations: AUC-Area under the curve; ACC-Accuracy; Spec.-Specificity; Sens.-Sensitivity. Conclusion Enteroccoccus expansion, Enterobacterales expansion, and microbial metabolite abundances accurately predicted LT patients who developed postoperative infection. Microbiome derived fecal metabolites identify alpha diversity and post operative infection (A) sPLS-DA using input matrix of sample metabolites and predicted microbial diversity group. Comparison between predicted groups was visualized on a grid with dividing lines and optimized by maximum distance between groups. Accuracy was: Low Diversity 77%, Medium Diversity 72%, and High Diversity 78%. Sensitivity ranged from 60-84%. Specificity ranged from 62-95%. (B) sPLS-DA using input matrix of sample metabolites and predicted postoperative infection. Comparison between outcomes was visualized on a grid with a dividing line and optimized by maximum distance between groups. Accuracy was 82.2% [73.9-89.1%], sensitivity was 63% [42.4-80.6], specificity was 88.9% [80-94.8%], and odds ratio was 13.6 [4.8-38.6]. Disclosures Eric Pamer, MD, Seres Therapeutics: Inventor on patent application # WPO2015179437A1 and #WO2017091753A1 and receives royalties from Seres Therapeutics, Inc.

  PublisherOA PDFDOI

• Intraoperative positive end-expiratory pressure and postoperative pulmonary complications: a patient-level meta-analysis of three randomised clinical trials

  British Journal of Anaesthesia · 2022 · 68 citations

  • Medicine
  • Anesthesia
  • Surgery
  DOI

• Combined heart‐liver‐kidney transplant: The university of Chicago medicine experience

  Clinical Transplantation · 2022 · 5 citations

  • Medicine
  • Intensive care medicine
  • Surgery

  BACKGROUND: Until recently, combined heart-liver-kidney transplantation was considered too complex or too high-risk an option for patients with end-stage heart failure who present with advanced liver and kidney failure as well. AIMS: The objective of this paper is to present our institution's best practices for successfully executing this highly challenging operation. At our institution, referral patterns are most often initiated through the cardiac team. RESULTS: Determinants of successful outcomes include diligent multidisciplinary patient selection, detailed perioperative planning, and choreographed care transition and coordination among all transplant teams. The surgery proceeds in three distinct phases with three different teams, linked seamlessly in planned handoffs. The selection and perioperative care are executed with determined collaboration of all of the invested care teams. CONCLUSIONS: Combined heart-liver-kidney transplantation can be successfully done by careful selection, coordination, and execution.

  PublisherDOI

• Reverse Takotsubo Stress Cardiomyopathy During Liver Transplantation

  Journal of Cardiothoracic and Vascular Anesthesia · 2022-12-12 · 3 citations

  article
  PublisherDOI

• 421.5: Extracorporeal Membrane Oxygenation Use in Orthotopic Liver Transplantation as a Viable Bridge to Transplant and Tool For Intraoperative and Postoperative Rescue

  Transplantation · 2022-09-01

  article

  Introduction: The use of extracorporeal membrane oxygenation (ECMO) to treat cardiac and pulmonary failure in orthotopic liver transplant (OLT) patients is uncommon and poorly understood despite the high morbidity and mortality related to these complications. We present one of the largest contemporary single-center case series of adult OLT patients requiring ECMO. Methods: This is a retrospective study of adult patients undergoing OLT at University of Chicago from January 2017 to March 2022, who required ECMO before, during, or after transplant. We excluded pediatric patients and patients undergoing simultaneous heart-liver and heart-liver-kidney transplantation. We conducted a chart review to identify relevant patient and operative factors, length of hospital stay, postoperative complications, postoperative survival days, length of time on ECMO, and mortality. Results: A total of 273 patients underwent OLT during the study period. Eleven patients required ECMO, of which ECMO was initiated in 4 patients pre-transplant (planned), 2 patients intraoperatively (rescue), and 5 patients postoperatively (rescue). Patient and operative factors in addition to outcomes are described in Table 1. Six of the 11 patients survived to discharge following ECMO decannulation and all six are alive today. Three different types of ECMO were used: venoarterial (peripheral femoral venoarterial cannulation and central cannulation), venovenous ECMO (peripheral femoral venovenous cannulation), right ventricular assist device (RVAD) with an oxygenator (via a dual lumen cannula placed in the internal jugular so that its inflow lumen is in the SVC and outflow lumen is in the pulmonary artery). Conclusions: ECMO may be used as a bridge to transplantation, for intraoperative rescue, and in the postoperative setting to provide mechanical support when medical management options for severe cardiopulmonary failure have been exhausted. Prior to using ECMO as a bridge to transplantation, evaluation should focus on the post-transplant reversibility of the condition requiring ECMO (e.g. advanced hepatopulmonary syndrome or severe right ventricular dysfunction). When ECMO is used for intraoperative rescue or postoperative decompensation, our outcomes are similar to previously published work. We noted improved outcomes when it is utilized for isolated hypoxemia without heart failure/vasoplegic shock. The exception to this observation was Patient 2 who had an RVAD/oxygenator placed prior to transplant for severe right ventricular dysfunction from volume overload with low pulmonary vascular resistance. In our experience, the need for rescue ECMO was unpredictable based on preoperative patient factors. Based on these results, we believe that ECMO is a viable strategy to provide additional support for patients with medically refractory but reversible hypoxemia or cardiogenic shock.

  PublisherDOI

• Intravascular Devices in the ICU

  Difficult decisions in surgery: an evidence-based approach · 2019-01-01

  book-chapterSenior authorCorresponding
  PublisherDOI

Frequent coauthors

• Marcus J. Schultz

  Amsterdam University Medical Centers

  12 shared

• Marcelo Gama de Abreu

  Outcomes Research Consortium

  8 shared

• Ary Serpa Neto

  Monash University

  7 shared

• Thomas Bluth

  Klinik und Poliklinik für Psychotherapie und Psychosomatik

  6 shared

• Thomas F. Gajewski

  University of Chicago

  4 shared

• Carlos Ferrando

  Hospital Israelita Albert Einstein

  4 shared

• Thomas Kiss

  TU Dresden

  4 shared

• Sabrine N.T. Hemmes

  The Netherlands Cancer Institute

  4 shared

Labs

• University of Chicago Department of Anesthesia and Critical CarePI

Education

• Ph.D., Immunology

  University of Chicago

  2006

• M.D.

  University of Chicago

  2007

• B.A., Biology & Mathematics

  Augustana College

  1997

• M.D., Anesthesiology and Critical Care Internship and Residency

  University of Chicago

  2011

• M.D., Critical Care Medicine Fellowship

  University of Chicago

  2012