About

Gary Alan Bass, MD MSc MBA FICS FEBS(Em Surg), is an Assistant Professor of Surgery at the Hospital of the University of Pennsylvania. He serves as an Attending Surgeon and Intensivist at the Hospital of the University of Pennsylvania, Penn Presbyterian Medical Center, and Pennsylvania Hospital. Dr. Bass is also a Senior Fellow at the Leonard Davis Institute for Health Economics at the University of Pennsylvania, and holds roles such as Senior Scholar at the Center for Perioperative Outcomes Research and Transformation (CPORT), and Director of the Penn Trauma International Program. His clinical expertise encompasses Surgical Critical Care, Emergency General Surgery, and Trauma Surgery. His research focuses on prospective multi-center observational cohort studies, randomized control trials, and retrospective surgical outcomes observational studies in Emergency General Surgery, Surgical Critical Care, and Trauma Surgery. He employs causal inferential methods and clinical epidemiology to better inform clinician decision support and patient outcomes, leveraging targeted trial emulation surgical outcomes research and mixed-methods implementation science.

Research topics

• Medicine
• Surgery
• Internal medicine
• Emergency medicine
• Intensive care medicine
• Virology
• Operations management
• Computer Science
• Political Science
• Nursing
• Medical emergency
• Environmental health
• Business
• Pathology
• Engineering
• Economics
• Medical education
• Marketing
• Management

Selected publications

• TXA after severe TBI: Learning and memory benefits are prominent only in males

  The Journal of Trauma: Injury, Infection, and Critical Care · 2026-01-05

  article

  BACKGROUND: Tranexamic acid (TXA), a commonly used pharmacotherapy, appears to preserve blood brain barrier integrity after traumatic brain injury (TBI) in males, but whether TXA confers equivalent neurocognitive benefit in female and male subjects after TBI remains unknown. We hypothesized that TXA unequally affects male and female learning and memory post-TBI. METHODS: CD1 male (M, n = 24) and female (F, n = 24) mice underwent controlled cortical impact (TBI) or sham craniotomy (Sh), receiving either TXA (60 mg/kg) or saline (placebo [P]) i.v., 1 hour later. For 14 days, mice underwent Morris water maze testing where improved learning/memory was indicated by traveling a shorter distance/reaching or crossing into target zones with greater frequency (Z1, platform quadrant; Z5, platform, Z6; Z7, concentric peri-platform zones). Brains were collected for tissue water determinations and neurological recovery was quantified daily using the Garcia neurological test and Neurological Severity Score across 14 days. RESULTS: Post-TBI TXA improved male spatial learning (crossing frequency into Z6 and Z7 [ p < 0.01]; latency to Z1 [ p < 0.01], Z5 [ p < 0.01], Z6 [ p < 0.01], and Z7 [ p < 0.01]). Tranexamic acid improved female learning solely in one parameter (Z7 latency; p < 0.01). Tranexamic acid improved male memory (frequency into Z5 [ p = 0.02] and Z6; duration in Z1 [ p = 0.01] and Z7 [ p = 0.04] and swimming velocity [ p < 0.01]). In females, TXA improved memory solely in one parameter (Z1 duration; p = 0.02). Tranexamic acid reduced only male cerebral edema.Tranexamic acid enhanced male mice Garcia Neurological Test scores early (first 3 days) and female mice scores, late (Day 11). Tranexamic acid only improved male Neurological Severity Score on Days 8 to 11. CONCLUSION: Post-TBI TXA benefits males more than females. Traumatic brain injury should be studied separately in males and females to identify sex-specific mechanisms of injury and recovery. ( J Trauma Acute Care Surg . 2026;100: 739-746. Copyright © 2025 Wolters Kluwer Health, Inc. All rights reserved.).

  PublisherDOI

• Impact of surgery and complications on <scp>GI</scp> recovery after <scp>SBO</scp> : Insights from the <scp>SnapSBO</scp> cohort

  Colorectal Disease · 2026-03-01

  articleOpen access

  BACKGROUND: Small bowel obstruction (SBO) is a common surgical emergency associated with impaired gastrointestinal (GI) function and prolonged recovery. The PRO-diGI patient-reported outcome measure (PROM) assesses patients' reports on key domains of appetite, nausea, bowel function, well-being and overall GI function. This study evaluated the influence of demographic and treatment factors on GI recovery following SBO and examined whether these associations persisted after balancing for baseline differences using propensity score matching (PSM). METHODS: An international prospective multicentre cohort study enrolled adult patients undergoing treatment for SBO of any aetiology. GI recovery was assessed using the PRO-diGI tool. Multivariable regression models were used to identify associations between clinical factors and PROM scores. Regression coefficients (β) with 95% confidence intervals were calculated. PSM was performed within the adhesional SBO subgroup to minimize confounding from differences in follow-up time and baseline characteristics. RESULTS: Of 1734 participants, 644 completed all PROM domains. Among patients contributing PROM data, surgical intervention was associated with improved nausea (β 5.9, 95% confidence interval 1.1-11.0) and overall GI function (β 6.8, 95% confidence interval 0.54-13.0) scores. Complications were linked to worse nausea (β -9.3, 95% confidence interval -17.0 to -1.7), well-being (β -17.0, 95% confidence interval -29.0 to -4.3), and overall function (β -12.0, 95% confidence interval -22.0 to -1.4). Previous nonoperative SBO episodes were associated with reduced appetite scores (β -7.3, 95% confidence interval -13.0 to -1.7). In the adhesion PSM cohort, overall GI function remained higher after surgery, and laparoscopic adhesiolysis was associated with superior appetite and overall function scores. DISCUSSION: Surgical treatment without complications was associated with improved patient-reported GI recovery after SBO. Persistence of these associations following matching indicates that patient-reported GI recovery differs across treatment pathways in selected patients, supporting the feasibility and discriminatory value of PRO-diGI as a patient-centred outcome measure.

  PublisherDOI

• Techniques for Mesoappendix Division and Appendiceal Stump Closure: A Comparative Review

  The American Surgeon · 2026-02-22

  article

  Acute appendicitis is a leading cause of emergency abdominal surgery, with laparoscopic appendectomy (LA) established as the gold standard treatment. Notwithstanding its extensive utilization, there is no agreement on the most effective method for closing the appendiceal stump and dividing the mesoappendix. This review sought to assess existing treatments in terms of surgical duration, hospital length of stay (LOS), complications, and cost-effectiveness. A comprehensive review of 53 studies was performed. Eligible studies included adult patients undergoing appendectomy and examined various procedures for appendiceal stump closure and mesoappendix division. The primary outcomes were surgical duration and LOS; the secondary objectives were postoperative complications and cost-effectiveness. For appendiceal stump closure, clips and staples were frequently linked to decreased surgical duration in comparison to ligatures or sutures, although outcomes varied. Clips were also associated with a reduced length of hospital stay. Cost-effectiveness analyses consistently found clips to be the most economical option for stump closure, with staples the most expensive. Complication rates were largely comparable, though loop ligatures were linked to more organ/space infections, and clips showed higher rates of surgical site infections in some studies. For mesoappendix division, electrocautery and energy devices generally shortened operative time compared with mechanical methods. Electrocautery was the least costly for mesoappendix division, while energy devices tended to increase costs. Division of the mesoappendix and appendiceal stump closure can be achieved with a wide range of techniques and tools. The optimal treatment strategy varies significantly based on the outcome investigated.

  PublisherDOI

• Dogma, data, and decision-making: a history of treatment for small-bowel obstruction

  World Journal of Emergency Surgery · 2026-01-14

  articleOpen access1st authorCorresponding

  BACKGROUND: Mechanical small-bowel obstruction (SBO) has been recognized since antiquity. We systematically review the evolution of its diagnosis and treatment, with emphasis on surgical milestones, influential surgeons, and procedural advances alongside the development of imaging and non-operative therapy. METHODS: We searched primary historical texts, monographs, and PubMed-indexed articles (inception to July 2025) for descriptions of mechanical SBO management. Data on key innovations, figures, outcomes, and global knowledge sharing were extracted and chronologically synthesized. Narrative synthesis followed SANRA criteria for scholarly reviews with emphasis on clarity of scope, critical interpretation, and structured presentation of key developments. RESULTS: Early sources solely describe non-surgical measures. In one of the first invasive interventions, Praxagoras of Cos (circa 350 BCE) reportedly advocated for surgical intervention in cases of intestinal obstruction, describing a decompressive enterocutaneous fistula as a therapeutic measure when purgation failed. Operative release of strangulated hernia was re-introduced by Ambroise Paré in the sixteenth century. Ether anesthesia (1846) and antisepsis (1867) enabled safe laparotomy; shortly thereafter, Sir Frederick Treves formalized the core operative principles in 1884. Plain abdominal radiography (1900s) improved diagnosis while Owen Wangensteen's nasogastric suction (1931) reduced mortality from > 60% to ~ 5%. Antibiotics, intravenous fluids, and stapled anastomoses further enhanced outcomes. Computed tomography (1980s) became the diagnostic gold standard, guiding selective non-operative management with enteral decompression and hyperosmolar contrast administration. Minimally invasive adhesiolysis, first embarked upon in the 1990s, now benefits carefully selected patients. CONCLUSIONS: Mechanical SBO care has evolved from basic supportive measures to structured, evidence-based therapy. Each advance addressed a specific clinical barrier: anesthesia enabled laparotomy, radiography enabled diagnosis, and decompression enabled non-operative management. As a result, SBO now exemplifies how iterative innovation can transform a once highly morbid emergency into a condition amenable to algorithmic, protocol-driven care. This historical arc offers instructive parallels for current surgical challenges.

  PublisherDOI

• ESTES recommendations for the treatment of polytrauma—a European consensus based on the German S3 guidelines for the treatment of patients with severe/multiple injuries

  European Journal of Trauma and Emergency Surgery · 2025-04-11 · 10 citations

  reviewOpen access

  INTRODUCTION: Considerable heterogeneity exists in the configuration and implementation maturity of trauma systems across European healthcare settings, and the opportunities for guideline-informed high-quality care varies considerably. Therefore, the European Society of Trauma and Emergency Surgery (ESTES), with its constituent national societies, has developed comprehensive consensus recommendations for care-context appropriate treatment of polytrauma patients in Europe, from the pre-hospital setting to the first surgical phase. METHODS: Adhering to the RAND/UCLA Appropriateness Method (RAM), ESTES conducted a three-round modified Delphi consensus. National society expert delegates assessed Grade of Recommendation (GoR) A and Good Clinical Practice Points (GPP) elements of the German Society of Trauma Surgery (DGU) "S3 guidelines for polytrauma/severe injury management" for appropriateness and implementability within their respective healthcare systems. RESULTS: In the first consensus round, 82 GoR A and 57 GPP recommendations were analysed. Of these, seven GPP were rephrased for clarity and four were removed due to redundancy or conflicting content. Consequently, 135 recommendations (82 GoR A and 53 GPP) remained, with 128 (77 GoR A and 51 GPP) deemed appropriate and necessary, and seven as uncertain due to expert disagreement. CONCLUSION: These ESTES recommendations constitute the first cohesive Europe-wide framework for managing the polytrauma patient from the prehospital setting to the end of the first surgical phase. They serve as a foundational tool for the development of national guidelines, particularly in regions with evolving trauma systems, and promote alignment towards a uniform standard-of-care across Europe.

  PublisherOA PDFDOI

• Disorders of Lymphatic Architecture and Flow in Critical Illness

  Critical Care Medicine · 2025-01-07 · 2 citations

  review

  OBJECTIVES: To provide a narrative review of disordered lymphatic dynamics and its impact on critical care relevant condition management. DATA SOURCES: Detailed search strategy using PubMed and Ovid Medline for English language articles (2013-2023) describing congenital or acquired lymphatic abnormalities including lymphatic duct absence, injury, leak, or obstruction and their associated clinical conditions that might be managed by a critical care medicine practitioner. STUDY SELECTION: Studies that specifically addressed abnormalities of lymphatic flow and their management were selected. The search strategy time frame was limited to the last 10 years to enhance relevance to current practice. DATA EXTRACTION: Relevant descriptions or studies were reviewed, and abstracted data were parsed into structural or functional etiologies, congenital or acquired conditions, and their management within critical care spaces in an acute care facility. DATA SYNTHESIS: Abnormal lymph flow may be identified stemming from congenital lymphatic anomalies including lymphatic structure absence as well as acquired obstruction or increased flow from clinical entities or acute therapy. Macro- and microsurgical as well as interventional radiological techniques may address excess, inadequate, or obstructed lymph flow. Patients with deranged lymph flow often require critical care, and those who require critical care may concomitantly demonstrate deranged lymph flow that adversely impacts care. CONCLUSIONS: Critical care clinicians ideally demonstrate functional knowledge of conditions that are directly related to, or are accompanied by, deranged lymphatic dynamics to direct timely diagnostic and therapeutic interventions during a patient's ICU care episode.

  PublisherDOI

• From rare procedure to institutional capability: a proposal to embed systematic training and adoption of emergency front of neck access

  British Journal of Anaesthesia · 2025-10-08 · 2 citations

  reviewOpen access
  PublisherOA PDFDOI

• Long-term outcome of patient choice of surgery or active surveillance following a clinical complete response to neoadjuvant chemoradiotherapy for oesophageal cancer

  European Journal of Surgical Oncology · 2025-11-06 · 1 citations

  article
  PublisherDOI

• Institutional Competence in Rigid Bronchoscopy for Oxygenation–Ventilation Rescue Is Vital Within the Difficult-Airway Continuum

  Anesthesiology Clinics · 2025-12-22

  articleSenior author
  PublisherDOI

• Initial Adhesive Small Bowel Obstruction Management Pathway Drives Infectious Complication Occurrence

  Surgical Infections · 2025-09-17 · 1 citations

  articleOpen accessSenior author

  INTRODUCTION: The Bologna guideline outlines three small bowel obstruction (SBO) management pathways. It remains unclear how pathway selection influences post-operative infections. METHODS: A multi-national, prospective, observational, audit of SBO management (November 1, 2023-May 31, 2024) captured demographics, care, and outcomes. Patients were grouped by pathway (successful non-operative management [NOM], NOM followed by surgery [NOM-T], direct to surgery [DTS]). Intergroup comparisons by chi-square or Fisher exact test, significance for p < 0.05. RESULTS: A total of 1,737 patients were assessed across 21 countries (850 NOM, 379 NOM-T, 508 DTS). Operative cohorts demonstrated similar age (NOM-T 65.2 ± 17.3 vs. DTS 65.5 ± 18.4 y; p = 0.834) and gender (NOM-T 53.6% vs. DTS, 52% female; p = 0.688). Comorbidities were more frequent in patients undergoing NOM-T (77.8%) versus DTS (69.7%; p < 0.001). DTS demonstrated more intestinal ischemia (NOM-T 22.8% vs. DTS 33%; p = 0.002). Time to OR was longer in NOM-T (43.8 ± 30.6 vs. DTS 12.4 ± 15.2 h; p < 0.001). Hospital length of stay (LOS) (NOM-T 12.4 ± 15.2 vs. DTS 7.7 ± 8.0 d; p < 0.001) and LOS (NOM-T 10.1 ± 10.4 vs. DTS 6.6 ± 9.1 d; p < 0.001) were longer in NOM-T. Superficial wound dehiscence (3.9%) and fascial dehiscence (2.6%) were uncommon. Overall surgical site infection (SSI) incidence was similar (NOM-T 8.7% vs. DTS 7.7%; p = 0.578). Deep SSI overall frequency was low (3.9%) but increased in NOM-T (5.5%) versus DTS (2.8%, p = 0.035). CONCLUSIONS: An NOM trial before operation for adhesive SBO seems to increase deep SSI risk and likely reflects time to OR as well as hospital and surgeon factors-elements that merit specific evaluation.

  PublisherOA PDFDOI

Frequent coauthors

• Daniel C. Cullinane

  Maine Medical Center

  419 shared

• Kosar Khwaja

  McGill University Health Centre

  401 shared

• Jerry Cheriyan

  Kern Medical Center

  400 shared

• Laura Petrey

  Baylor University Medical Center

  400 shared

• David S. Morris

  400 shared

• Gregory P. Schaefer

  Vanderbilt University Medical Center

  400 shared

• Ashlee E. Moore

  Holmes Regional Medical Center

  400 shared

• Bryce R. H. Robinson

  University of California, San Francisco

  400 shared

Education

• PhD

  Orebro University

• Master of Science by Research (MSc), Human Anatomy & Physiology

  University College Dublin

  2005