Elevated Hb A1C level and revisional bariatric surgery complications.

BACKGROUND: Elevated Hb A1C is a modifiable risk factor for postoperative complications. However, in bariatric surgery, as published by our group and others, elevated preoperative Hb A1C may not be associated with increased postoperative complications. Previous literature has focused on primary bariatric surgery and has excluded the higher-risk revisional surgery cohort. OBJECTIVE: To assess the impact of Hb A1C on early postoperative outcomes in patients requiring revisional bariatric surgery. SETTING: Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database. METHODS: We undertook a retrospective review of patients undergoing revisional bariatric surgery between 2017 and 2018 from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database. Two groups were studied, defined by Hb A1C cutoff, ≤8% versus >8% and ≤10% versus >10%. Early postoperative complications were compared at each threshold, with the primary outcome defined as a composite of all complications. Propensity score matching (PSM) was used with one-to-one matching for covariates, and the complication rates before and after PSM were calculated and assessed by Fisher's exact test and conditional logistic regression, respectively. RESULTS: A total of 16,234 patients had undergone revisional bariatric surgery. After PSM, elevated Hb A1C was not associated with worse outcomes. No significant difference was seen in the composite outcomes for Hb A1C ≤8% versus Hb A1C >8% (P = .22) or for patients with Hb A1C ≤10% versus Hb A1C >10% (P < .46). There were no differences in individual outcomes such as surgical-site infections, cardiopulmonary complications, or readmissions/reinterventions. CONCLUSION: In this study of revisional bariatric patients, elevated Hb A1C >8% or >10% was not associated with increased postoperative complications. Prospective studies are needed to investigate this further.

Multiparameter screen optimizes immunoprecipitation.

Immunoprecipitation (IP) coupled with mass spectrometry effectively maps protein-protein interactions when genome-wide, affinity-tagged cell collections are used. Such studies have recorded significant portions of the compositions of physiological protein complexes, providing draft 'interactomes'; yet many constituents of protein complexes still remain uncharted. This gap exists partly because high-throughput approaches cannot optimize each IP. A key challenge for IP optimization is stabilizing in vivo interactions during the transfer from cells to test tubes; failure to do so leads to the loss of genuine interactions during the IP and subsequent failure to detect. Our high-content screening method explores the relationship between in vitro chemical conditions and IP outcomes, enabling rapid empirical optimization of conditions for capturing target macromolecular assemblies.

Combined liver transplantation and sleeve gastrectomy: Report of a brief-interval staged approach.

Pretransplantation bariatric surgery in patients with high Model for End-Stage Liver Disease (MELD) score is fraught with risks. Bariatric surgery after liver transplantation (LT) may be complicated by surgical adhesions but could have advantages if performed at the time of transplantation. We investigated a method of brief-interval staging combining LT and sleeve gastrectomy (SG). LT recipients with a body mass index (BMI) > 40 kg/m 2 received an SG during the same hospitalization as the LT (LT/SG), at the same time as a planned brief-interval return to the operating room for biliary anastomosis. Differences in intraoperative attributes of the LT (Stage 1) versus SG (Stage 2) procedures were analyzed using Wilcoxon signed-rank test with significance p < 0.05 and compared with patients with obesity having a two-stage LT without SG. A total of 14 cases {median MELD score 33 (interquartile range [IQR], 18-40)} were compared with 28 controls; 60% were critically ill prior to surgery with mechanical ventilation, vasopressors, or continuous renal replacement therapy. Median interval between procedures was 16.1 (IQR, 12.5-22.7) hours for cases and 12.2 (IQR, 11.1-16.6) hours for controls, p  = 0.27. Median BMI at LT/SG was 47.0 (IQR, 41.7-51.3) kg/m 2 versus 38.1 (IQR, 35.7-39.8) kg/m 2 for controls, p < 0.001. At 1 year, median excess body weight loss was 74.0% (IQR, 46.2%-78.7%) in cases and 15.8% (IQR, -5.4% to 62.6%) in controls, p  = 0.13; total weight loss was 38.1% (IQR, 23.9-42.9) in cases versus 7.7% (IQR, -2.4% to 27.6%) for controls, p  = 0.03. Graft survival at 1 year was 92.9% for cases and 89.3% for controls with similar early postoperative outcomes. This proof-of-concept study revealed that a brief-interval SG during LT is feasible in patients with high MELD and resulted in sustained weight loss at 1 year with similar graft survival. Further studies are needed to determine an optimal strategy.

Elevated hemoglobin A1c level and bariatric surgery complications.

INTRODUCTION: In cardiac and orthopedic surgery, elevated glycosylated hemoglobin (HbA1c) is a modifiable risk factor for postoperative complications. However, in bariatric surgery, there is insufficient evidence to assess the effectiveness of preoperative HbA1c assessment and its association with postoperative complications. The objective of this study was to assess the impact of HbA1c on early postoperative outcomes in bariatric surgery patients. METHODS: Patients who underwent laparoscopic sleeve gastrectomy and laparoscopic Roux-En-Y Gastric Bypass between 2017 and 2018 were selected for a retrospective review from the metabolic and bariatric surgery accreditation and quality improvement program (MBSAQIP) database. The study population of 118,742 patients was analyzed for our primary outcome which was defined as a composite of any postoperative complications occurring within 30 days. Two groups were defined by HbA1c cutoff: comparison point A (≤ 8% vs > 8%) and comparison point B (≤ 10% vs > 10%). Procedure-related complications were also examined on subgroup analysis. Propensity score matching (PSM) was used with one-to-one matching. The complication rates before and after PSM were calculated and assessed by Fisher's exact test and conditional logistic regression, respectively. RESULTS: After PSM, demographic and clinical characteristics were all balanced and elevated HbA1C was not associated with worse outcomes. After adjusting for underlying comorbidities, there was no statistically significant difference seen in the composite outcome for comparison point A HbA1C ≤ 8 and HbA1C > 8 (p = 0.22). For comparison point B, patients with HbA1C ≤ 10 had more composite complications compared to patients with HbA1C > 10 (p < 0.001). Also, on subgroup analysis after PSM for procedure-specific complications, patients above the cutoff threshold of 8 did not have worsened composite outcomes (p = 0.58 and 0.89 for sleeve and bypass, respectively). Again, at cutoff threshold of 10, patients in HbA1C ≤ 10 had more composite complications (p = 0.001 and 0.007 for sleeve and bypass, respectively). CONCLUSION: In this study of bariatric patients, elevated HbA1c > 8% or 10% was not associated with increased postoperative complications. HbA1c lower than 10% was associated with some types of adverse outcomes in this bariatric dataset. More studies are needed to investigate these findings further. A high HbA1c alone may not disqualify a patient from proceeding with bariatric surgery.

Effectiveness of Bariatric Surgery in Increasing Kidney Transplant Eligibility in Patients with Kidney Failure Requiring Dialysis.

PURPOSE: Severe obesity can increase risk of complications after kidney transplantation. There is a paucity of literature on bariatric surgery outcomes in renal transplant candidates. The objective of this study was to analyze outcomes of bariatric surgery as a weight reduction strategy for patients with kidney failure to enhance eligibility for kidney transplantation. MATERIALS AND METHODS: We performed a retrospective analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database at a single institution for patients with chronic kidney disease receiving hemodialysis therapy (CKD G5D) undergoing bariatric surgery between 2011 and 2018. RESULTS: Of 2363 patients who underwent bariatric surgery, 38 (1.6%) had CKD G5D; median age (range) was 49 years (33; 69), 52.6% were female, and mean BMI was 44.2 kg/m2. Twenty-four patients underwent laparoscopic Roux-en-Y gastric bypass (LRYGB), and 14 patients underwent laparoscopic sleeve gastrectomy. Seventeen patients (46%, n=37) had a BMI≤35 at 6 months, while 25 patients (75.8%, n=33) achieved a BMI≤35 at 12 months. Of these, 18 patients (47%) were listed for kidney transplant, and 8 patients (21%) received kidney transplant. There was no statistically significant difference between sleeve and LRYGB procedures in patients who reached BMI of 35 at 12 months (P=0.58). Median length of stay was 2.3 days. Thirty-day readmission rate was 2 patients (5.3%), and 2 patients (5.3%) required reoperation (one for bleeding, one for acute recurrent hiatal hernia). No mortality occurred. CONCLUSION: Laparoscopic bariatric surgery offers effective weight loss for CKD G5D patients to achieve transplant eligibility with acceptable outcomes.

Intestinal stem cell-derived enteroids from morbidly obese patients preserve obesity-related phenotypes: Elevated glucose absorption and gluconeogenesis.

OBJECTIVE: The mechanisms behind the efficacy of bariatric surgery (BS) for treating obesity and type 2 diabetes, particularly with respect to the influence of the small bowel, remain poorly understood. In vitro and animal models are suboptimal with respect to their ability to replicate the human intestinal epithelium under conditions induced by obesity. Human enteroids have the potential to accelerate the development of less invasive anti-obesity therapeutics if they can recapitulate the pathophysiology of obesity. Our aim was to determine whether adult stem cell-derived enteroids preserve obesity-characteristic patient-specific abnormalities in carbohydrate absorption and metabolism. METHODS: We established 24 enteroid lines representing 19 lean, overweight, or morbidly obese patients, including post-BS cases. Dietary glucose absorption and gluconeogenesis in enteroids were measured. The expression of carbohydrate transporters and gluconeogenic enzymes was assessed and a pharmacological approach was used to dissect the specific contribution of each transporter or enzyme to carbohydrate absorption and metabolism, respectively. RESULTS: Four phenotypes representing the relationship between patients' BMI and intestinal dietary sugar absorption were found, suggesting that human enteroids retain obese patient phenotype heterogeneity. Intestinal glucose absorption and gluconeogenesis were significantly elevated in enteroids from a cohort of obese patients. Elevated glucose absorption was associated with increased expression of SGLT1 and GLUT2, whereas elevated gluconeogenesis was related to increased expression of GLUT5, PEPCK1, and G6Pase. CONCLUSIONS: Obesity phenotypes preserved in human enteroids provide a mechanistic link to aberrant dietary carbohydrate absorption and metabolism. Enteroids can be used as a preclinical platform to understand the pathophysiology of obesity, study the heterogeneity of obesity mechanisms, and identify novel therapeutics.

Bariatric Surgery in End-Stage Heart Failure: Feasibility in Successful Attainment of a Target Body Mass Index.

INTRODUCTION: Orthotopic heart transplantation (OHT) is contraindicated in morbidly obese patients with end-stage heart failure (HF), for whom cardiac allograft is the only means for long-term survival. Bariatric surgery may allow them to achieve target body mass index (BMI) for OHT METHODS: From 4/2014 to 12/2018, 26 morbidly obese HF patients who did not meet BMI eligibility criteria for OHT underwent laparoscopic bariatric surgery. Outcomes of interest were median difference in BMI, number of patients achieving target BMI for OHT, and 30-day mortality. RESULTS: Median age was 49 (IQR 14) years, and 13 (50%) were women. HF was mainly systolic (15 patients, 58%). The median LVEF was 27% (IQR 37%). At the time of bariatric surgery, 12 (46%) patients had mechanical circulatory support: 2 (8%) concomitant left ventricular assist device (LVAD) placements, 8 (31%) LVAD already-in-place, and 2 (8%) intra-aortic balloon pumps. There was no 30-day mortality, but one mortality on postoperative day 48. Over a median follow-up of 6 months (range 0-36 months, IQR 17), there was a significant reduction in BMI (p<0.0001). The median postoperative BMI was 36.7 (IQR 8.7), compared to preoperative median BMI of 42.7 (IQR 9.4). Target BMI of < 35 was achieved in 11 (42%) patients. Three patients (12%) have undergone OHT. CONCLUSION: Bariatric surgery in end-stage HF is feasible and results in a high number of patients achieving target BMI, increasing their probability of undergoing OHT. The presence of a LVAD should not preclude these patients from undergoing a bariatric intervention.

Post-bariatric surgery lab tests: are they excessive and redundant?

INTRODUCTION: Following bariatric surgery, ongoing postoperative testing is required to measure nutritional deficiencies; the purpose of this study was to quantify the prevalence of these nutritional deficiencies based on two-year follow-up tests at recommended time points. METHODS AND PROCEDURES: A retrospective data analysis was conducted of all laboratory tests for bariatric patients who underwent surgery between May 2016 and January 2018 with available lab data (n = 397). Results for nine different nutritional labs were categorized into six recommended postoperative time periods based on time elapsed since the procedure date. Binary variables were created for each laboratory result to calculate descriptive statistics of abnormalities for each lab test over time and used in the individual GEE logistic regression models. Grouped logistic regression examined the total nutritional deficiencies of the nine combined nutrients considering total available labs. RESULTS: Multiple lab tests indicated a very low frequency of abnormalities (e.g., Vitamin A, Vitamin B12, Copper, and Folate). Many of the nine included nutritional labs had an average deficiency of less than 10% across all time points. The grouped logistic model found preoperative nutritional deficiency to be predictive of postoperative nutritional deficiency (OR 3.70, p < 0.001). CONCLUSIONS: We found the vast majority of routine lab test results to be normal at multiple time points. Current practice can add up to significant lab expenses over time. The frequency of postoperative testing in this population may be redundant and of very little value. Unnecessary follow-up laboratory testing costs the patients and the health care system in both time and resources. Patients with preoperative deficiencies appear to be at higher risk for nutritional deficiencies when compared to bariatric surgery patients that did not have preoperative nutritional deficiencies. Future research should focus on defining cost effective postoperative lab testing guidelines for at risk bariatric patients.

Correction to: Longitudinal Impacts of Gastric Bypass Surgery on Pharmacodynamics and Pharmacokinetics of Statins.

In the original article the authors failed to include the following footnote.

Longitudinal Impacts of Gastric Bypass Surgery on Pharmacodynamics and Pharmacokinetics of Statins.

PURPOSE: Undergoing Roux-en-Y gastric bypass (RYGB) is expected to affect orally administered drug absorption. Statins are commonly prescribed to patients with obesity for the prevention of atherosclerotic cardiovascular diseases by lowering cholesterol. This is the first longitudinal prospective study on impacts of RYGB on weight loss, pharmacodynamics, and pharmacokinetics of atorvastatin, rosuvastatin, and simvastatin, and their active metabolites, up to 1-year post-surgery. METHODS: Forty-six patients were recruited, five patients on atorvastatin, twelve on rosuvastatin, nine on simvastatin, and twenty on no statin. The concentrations of atorvastatin, rosuvastatin, and simvastatin with their active metabolites were monitored. RESULTS: Mean plasma concentrations of atorvastatin and metabolites and rosuvastatin normalized by the unit dose [(nM)/(mg/kg)] decreased by 3- to 6-month post-surgery. Conversely, simvastatin and its metabolite concentrations increased up to 6-month post-surgery, then declined to preoperative levels by 1-year post-surgery. The metabolisms of atorvastatin to hydroxyl-metabolites and simvastatin to simvastatin acid were decreased after RYGB. The weight loss and PD outcomes were comparable between statin and non-statin groups suggesting the key impacts were from RYGB. The discontinuation or reduction of dose of atorvastatin or rosuvastatin post-RYGB exhibited rebounds of LDL levels in some subjects, but the rebound was not apparent with patients on simvastatin pre-surgery. CONCLUSION: Discontinuations of statin dosing post-RYGB require LDL monitoring and reducing the dose to half seems to have better results. Patients on statin treatment post-RYGB should be followed-up closely based on our pharmacokinetic findings, to ensure therapeutic effects of the treatment with minimal adverse effects.

Simultaneous LC-MS/MS analysis of simvastatin, atorvastatin, rosuvastatin and their active metabolites for plasma samples of obese patients underwent gastric bypass surgery.

Statins, HMG-CoA reductase inhibitors, are considered the first line treatment of hyperlipidemia to reduce the risk of atherosclerotic cardiovascular diseases. The prevalence of hyperlipidemia and the risk of atherosclerotic cardiovascular diseases are higher in obese patients. Published methods for the quantification of statins and their active metabolites did not test for matrix effect of or validate the method in hyperlipidemic plasma. A sensitive, specific, accurate, and reliable LC-MS/MS method for the simultaneous quantification of simvastatin (SMV), active metabolite of simvastatin acid (SMV-A), atorvastatin (ATV), active metabolites of 2-hydroxy atorvastatin (2-OH-ATV), 4-hydroxy atorvastatin (4-OH-ATV), and rosuvastatin (RSV) was developed and validated in plasma with low (52-103 mg/dl, <300 mg/dl) and high (352-403 mg/dl, >300 mg/dl) levels of triglyceride. The column used in this method was ACQUITY UPLC BEH C18 column (2.1 × 100 mm I.D., 1.7 µm). A gradient elution of mobile phase A (10 mM ammonium formate and 0.04% formic acid in water) and mobile phase B (acetonitrile) was used with a flow rate of 0.4 ml/min and run time of 5 min. The transitions of m/z 436.3 → 285.2 for SMV, m/z 437.2 → 303.2 for SMV-A, m/z 559.2 → 440.3 for ATV, m/z 575.4 → 440.3 for 2-OH-ATV and 4-OH-ATV, m/z 482.3 → 258.1 for RSV, and m/z 412.3 → 224.2 for fluvastatin (internal standard, IS) were determined by Selected Reaction Monitoring (SRM) method to detect transitions ions in the positive ion mode. The assay has a linear range of 0.25 (LLOQ) -100 ng/ml for all six analytes. Accuracy (87-114%), precision (3-13%), matrix effect (92-110%), and extraction recovery (88-100%) of the assay were within the 15% acceptable limit of FDA Guidelines in variations for plasma with both low and high triglyceride levels. The method was used successfully for the quantification of SMV, ATV, RSV, and their active metabolites in human plasma samples collected for an ongoing clinical pharmacokinetic and pharmacodynamic study on patients prior to and post gastric bypass surgery (GBS).

Routine use of mesh during hiatal closure is safe with no increase in adverse sequelae.

BACKGROUND: Primary laparoscopic hiatal repair with fundoplication is associated with a high recurrence rate. We wanted to evaluate the potential risks posed by routine use of onlay-mesh during hiatal closure, when compared to primary repair. METHODS: Utilizing single-institutional database, we identified patients who underwent primary laparoscopic hiatal repair from January 2005 through December 2014. Retrospective chart review was performed to determine perioperative morbidity and mortality. Long-term results were assessed by sending out a questionnaire. Results were tabulated and patients were divided into 2 groups: fundoplication with hiatal closure + absorbable or non-absorbable mesh and fundoplication with hiatal closure alone. RESULTS: A total of 505 patients underwent primary laparoscopic fundoplication. Mesh reinforcement was used in 270 patients (53.5%). There was no significant difference in the 30-day perioperative outcomes between the 2 groups. No clinically apparent erosions were noted and no mesh required removal. Standard questionnaire was sent to 475 patients; 174 (36.6%) patients responded with a median follow-up of 4.29 years. Once again, no difference was noted between the 2 groups in terms of dysphagia, heartburn, long-term antacid use, or patient satisfaction. Of these, 15 patients (16.9%, 15/89) in the 'Mesh' cohort had symptomatic recurrence as compared to 19 patients (22.4%, 19/85) in the 'No Mesh' cohort (p = 0.362). A reoperation was necessary in 6 patients (6.7%) in the 'Mesh' cohort as compared to 3 patients (3.5%) in the 'No Mesh' cohort (p = 0.543). CONCLUSIONS: Onlay-mesh use in laparoscopic hiatal repair with fundoplication is safe and has similar short and long-term results as primary repair.

Revisional Bariatric Surgery.

Revisional bariatric procedures are increasingly common. With more primary procedures being performed to manage severe obesity and its complications, 5% to 8% of these procedures will fail, requiring revisional operation. Reasons for revisional bariatric surgery are either primary inadequate weight loss, defined as less than 25% excess body weight loss, or weight recidivism, defined as a gain of more than 10 kg based on the nadir weight; however, each procedure also has inherit specific complications that can also be indications for revision. This article reviews the history of each primary bariatric procedure, indications for revision, surgical options, and subsequent outcomes.

Human Intestinal Enteroids: a New Model To Study Human Rotavirus Infection, Host Restriction, and Pathophysiology.

UNLABELLED: Human gastrointestinal tract research is limited by the paucity of in vitro intestinal cell models that recapitulate the cellular diversity and complex functions of human physiology and disease pathology. Human intestinal enteroid (HIE) cultures contain multiple intestinal epithelial cell types that comprise the intestinal epithelium (enterocytes and goblet, enteroendocrine, and Paneth cells) and are physiologically active based on responses to agonists. We evaluated these nontransformed, three-dimensional HIE cultures as models for pathogenic infections in the small intestine by examining whether HIEs from different regions of the small intestine from different patients are susceptible to human rotavirus (HRV) infection. Little is known about HRVs, as they generally replicate poorly in transformed cell lines, and host range restriction prevents their replication in many animal models, whereas many animal rotaviruses (ARVs) exhibit a broader host range and replicate in mice. Using HRVs, including the Rotarix RV1 vaccine strain, and ARVs, we evaluated host susceptibility, virus production, and cellular responses of HIEs. HRVs infect at higher rates and grow to higher titers than do ARVs. HRVs infect differentiated enterocytes and enteroendocrine cells, and viroplasms and lipid droplets are induced. Heterogeneity in replication was seen in HIEs from different patients. HRV infection and RV enterotoxin treatment of HIEs caused physiological lumenal expansion detected by time-lapse microscopy, recapitulating one of the hallmarks of rotavirus-induced diarrhea. These results demonstrate that HIEs are a novel pathophysiological model that will allow the study of HRV biology, including host restriction, cell type restriction, and virus-induced fluid secretion. IMPORTANCE: Our research establishes HIEs as nontransformed cell culture models to understand human intestinal physiology and pathophysiology and the epithelial response, including host restriction of gastrointestinal infections such as HRV infection. HRVs remain a major worldwide cause of diarrhea-associated morbidity and mortality in children ≤5 years of age. Current in vitro models of rotavirus infection rely primarily on the use of animal rotaviruses because HRV growth is limited in most transformed cell lines and animal models. We demonstrate that HIEs are novel, cellularly diverse, and physiologically relevant epithelial cell cultures that recapitulate in vivo properties of HRV infection. HIEs will allow the study of HRV biology, including human host-pathogen and live, attenuated vaccine interactions; host and cell type restriction; virus-induced fluid secretion; cell-cell communication within the epithelium; and the epithelial response to infection in cultures from genetically diverse individuals. Finally, drug therapies to prevent/treat diarrheal disease can be tested in these physiologically active cultures.

A robust and non-obtrusive automatic event tracking system for operating room management to improve patient care.

BACKGROUND: Optimization of OR management is a complex problem as each OR has different procedures throughout the day inevitably resulting in scheduling delays, variations in time durations and overall suboptimal performance. There exists a need for a system that automatically tracks procedural progress in real time in the OR. This would allow for efficient monitoring of operating room states and target sources of inefficiency and points of improvement. STUDY DESIGN: We placed three wireless sensors (floor-mounted pressure sensor, ventilator-mounted bellows motion sensor and ambient light detector, and a general room motion detector) in two ORs at our institution and tracked cases 24 h a day for over 4 months. RESULTS: We collected data on 238 total cases (107 laparoscopic cases). A total of 176 turnover times were also captured, and we found that the average turnover time between cases was 35 min while the institutional goal was 30 min. Deeper examination showed that 38 % of laparoscopic cases had some aspect of suboptimal activity with the time between extubation and patient exiting the OR being the biggest contributor (16 %). CONCLUSION: Our automated system allows for robust, wireless real-time OR monitoring as well as data collection and retrospective data analyses. We plan to continue expanding our system and to project the data in real time for all OR personnel to see. At the same time, we plan on adding key pieces of technology such as RFID and other radio-frequency systems to track patients and physicians to further increase efficiency and patient safety.

Rapid, optimized interactomic screening.

We must reliably map the interactomes of cellular macromolecular complexes in order to fully explore and understand biological systems. However, there are no methods to accurately predict how to capture a given macromolecular complex with its physiological binding partners. Here, we present a screening method that comprehensively explores the parameters affecting the stability of interactions in affinity-captured complexes, enabling the discovery of physiological binding partners in unparalleled detail. We have implemented this screen on several macromolecular complexes from a variety of organisms, revealing novel profiles for even well-studied proteins. Our approach is robust, economical and automatable, providing inroads to the rigorous, systematic dissection of cellular interactomes.

A smart trocar for automatic tool recognition in laparoscopic surgery.

BACKGROUND: Operating rooms have become increasingly complex environments and more prone to errors because of loss of situation awareness. Adding computer intelligence to the operating room may help overcome these limitations particularly if the system can automatically track which step of an operation a surgeon is performing. To develop such a platform, it is necessary to track which laparoscopic instruments are being used and in which port they are inserted. This article describes the development and validation of a "Smart Trocar" that can automatically perform this function. METHODS: A Smart Trocar system prototype was developed that uses a wireless camera attached to a standard laparoscopic port and custom software algorithms. The system recognizes color wheels attached to the handle of a laparoscopic instrument and compares the unique color pattern to an instrument library for proper tool identification. The system was tested for reliability in a box trainer environment using a variety of tool positions and levels of room light illumination. RESULTS: Correct color classification was achieved in 96.7% of trials. There were no errors in detection of the color wheel in space. In addition, the distance of the color wheel from the camera did not influence results and correct classifications were evenly distributed among the 12 laparoscopic tool positions tested. CONCLUSION: This work describes a Smart Trocar system that identifies which laparoscopic tool is being used and in which port and proves its reliability. The system is an important element of a more comprehensive program being developed to automatically understand what step of an operation a surgeon is performing and use these data to improve situation awareness in the operating room.