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Dive into the research topics where John A. Aucar is active.

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Featured researches published by John A. Aucar.


Journal of The American College of Surgeons | 1999

Analysis of laparoscopy in trauma.

Raphael T. Villavicencio; John A. Aucar

BACKGROUND The optimum roles for laparoscopy in trauma have yet to be established. To date, reviews of laparoscopy in trauma have been primarily descriptive rather than analytic. This article analyzes the results of laparoscopy in trauma. STUDY DESIGN Outcome analysis was done by reviewing 37 studies with more than 1,900 trauma patients, and laparoscopy was analyzed as a screening, diagnostic, or therapeutic tool. Laparoscopy was regarded as a screening tool if it was used to detect or exclude a positive finding (eg, hemoperitoneum, organ injury, gastrointestinal spillage, peritoneal penetration) that required operative exploration or repair. Laparoscopy was regarded as a diagnostic tool when it was used to identify all injuries, rather than as a screening tool to identify the first indication for a laparotomy. It was regarded as a diagnostic tool only in studies that mandated a laparotomy (gold standard) after laparoscopy to confirm the diagnostic accuracy of laparoscopic findings. Costs and charges for using laparoscopy in trauma were analyzed when feasible. RESULTS As a screening tool, laparoscopy missed 1% of injuries and helped prevent 63% of patients from having a trauma laparotomy. When used as a diagnostic tool, laparoscopy had a 41% to 77% missed injury rate per patient. Overall, laparoscopy carried a 1% procedure-related complication rate. Cost-effectiveness has not been uniformly proved in studies comparing laparoscopy and laparotomy. CONCLUSIONS Laparoscopy has been applied safely and effectively as a screening tool in stable patients with acute trauma. Because of the large number of missed injuries when used as a diagnostic tool, its value in this context is limited. Laparoscopy has been reported infrequently as a therapeutic tool in selected patients, and its use in this context requires further study.


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2005

A review of surgical simulation with attention to validation methodology.

John A. Aucar; Nicholas R. Groch; Scott A. Troxel; Steve W. Eubanks

The use of simulation technology for teaching and evaluating surgical skills has gained considerable attention in recent years. This is driven by interest in quality of care, concerns over increasing operative complexity, constraints on the use of animal models, limited available patient material, medicolegal pressures, and fiscal mandates for cost-effective performance. Traditional mechanical models are yielding to techniques dependent on electronic technology, including virtual reality. Data to support the validity of simulation techniques for surgical training, assessment, and certification represent only a fraction of the literature available on the subject. Literature searches were conducted in MEDLINE and ERIC, covering the period from 1966 to the present. The electronic and bioengineering literature was not surveyed due to the extensive literature on technology development, distinct from assessment of context specific validity. The search results and the bibliographies of key review articles were examined to identify articles that contained original data, measured performance between cohorts, defined performance measures, and described a standard against which performance was compared. Most of the literature pertaining to simulation techniques for surgical training has been published within the past 5 years and consist of review, opinion, and feasibility articles. There is an emerging body of evidence to establish the validity of simulation techniques for assessing surgical skills. Further refinement of simulation techniques, identification of specific performance measures, longitudinal evaluations, and comparison to practice outcomes are still needed to establish the validity and the value of surgical simulation for teaching and assessing surgical skills prior to considering implementation for certification purposes.


Journal of Trauma-injury Infection and Critical Care | 1998

Pulmonary tractotomy as an abbreviated thoracotomy technique

Matthew J. Wall; Raphael T. Villavicencio; Charles C. Miller; John A. Aucar; Thomas A. Granchi; Kathleen R. Liscum; David Shin; Kenneth L. Mattox

BACKGROUND Operative abbreviated thoracotomy techniques in thoracic trauma include emergency center thoracotomy, ligation of major arterial branches, packing the thoracic cavity for diffuse bleeding, towel clip or Bogota bag closure of the chest, and pulmonary tractotomy. Pulmonary tractotomy with selective vascular ligation was originally described for deep through-and-through lung injuries that did not involve hilar vessels or airways. Pulmonary tractotomy has evolved into use as an abbreviated thoracotomy technique in patients with severe thoracic or multivisceral trauma. As with any operative technique in high-risk patients, specific procedure-related complications may occur and are analyzed herein. The objective of this manuscript is to review the indications, techniques, and results for pulmonary tractotomy in trauma patients requiring abbreviated thoracotomy. METHODS Medical records were retrospectively reviewed for 30 of 32 consecutive tractotomy patients treated at Ben Taub General Hospital, during a 3-year period. By using a model for logistic regression analysis, the characteristics of each patient and their clinical course were tested for impact on mortality. RESULTS Seventy percent of patients had at least one intraoperative parameter indicative of acidosis (pH < 7.2), coagulopathy (prothrombin time > 13.8 or partial thromboplastin time > 38.0 seconds), or hypothermia (core temperature < 34 degrees C), and 50% of patients manifested two of these three parameters. The mortality rate among the 30 patients was 17%. Three of the five patients who died were noted to be acidotic, coagulopathic, and hypothermic. Twelve of 25 patients who survived more than 1 day had at least one thoracic complication. There were no late deaths. There was one failed tractotomy and one missed injury. A second thoracotomy was not required for control of a lung injury in any patient. Logistic regression analysis showed that intraoperative blood loss was the only predictive factor for mortality. CONCLUSION Pulmonary tractotomy is a simple and effective technique in injured patients who require an abbreviated thoracotomy and has an acceptable mortality and complication rate. This follow-up report notes that as definitive therapy, tractotomy continues to allow for direct control of bleeding and air leak and obviates the need for formal resection.


Surgical Endoscopy and Other Interventional Techniques | 1999

Analysis of thoracoscopy in trauma

R. T. Villavicencio; John A. Aucar; Matthew J. Wall

AbstractBackground: The role of video-assisted thoracic surgery (VATS) in trauma has yet to be established. Up to the time of this writing, reviews of thoracoscopy in trauma have been primarily descriptive rather than analytic. This article analyzes the results of thoracoscopy (nonvideo and VATS) in trauma. Methods: Analysis was done by reviewing 28 nonoverlapping studies since the introduction of thoracoscopy in 1910, with a combined total of more than 500 patients. Results: Diagnostically, thoracoscopy has been used primarily to evaluate diaphragmatic injury, continued chest tube bleeding, and suspected cardiac injury. Thoracoscopy has a 98% (188/191 patients) accuracy rate in diagnosing diaphragmatic injuries. Therapeutically, thoracoscopy has been used primarily to control chest tube bleeding, evacuate retained hemothoraces, and evacuate empyemas. Thoracoscopy is 90% (89/99 patients) effective in evacuating retained hemothoraces, 86% (19/22 patients) effective in evacuating empyemas, and 82% (33/40 patients) effective in controlling chest tube bleeding. Thoracoscopy benefits include preventing 62% (323/514) of trauma patients from having a thoracotomy or laparotomy. Risks include a 2% (11/534 patients) procedure-related complication rate and a 0.8% (4/471 patients) missed injury rate. Technical failure rates are 10% (10/99 patients) and 4% (7/199 patients) in evacuation of retained hemothoraces and evaluation of diaphragmatic injuries, respectively. Conclusions: Analysis suggests that thoracoscopy (nonvideo and VATS) can be applied safely and effectively in the care of the injured patient.


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2004

Traumatic abdominal wall hernia: same-admission laparoscopic repair.

John A. Aucar; Biggers B; Silliman Wr; Julian E. Losanoff

Traumatic abdominal wall hernias are uncommon. They are traditionally treated with open surgery. We report a case repaired using laparoscopic technique and prosthetic reinforcement.


Shock | 2003

Intraoperative detection of traumatic coagulopathy using the activated coagulation time

John A. Aucar; Peter Norman; Elizabeth Whitten; Thomas S. Granchi; Kathleen R. Liscum; Matthew J. Wall; Kenneth L. Mattox

Traumatic coagulopathy manifests as a hypocoagulable state associated with hypothermia, acidosis, and coagulation factor dilution. The diagnosis must be made clinically because traditional coagulation tests are neither sensitive nor specific and take too long to be used for intraoperative monitoring. We hypothesized that the activated coagulation time (ACT) would reflect the global coagulation status of traumatized patients and would become elevated as coagulation reserves become exhausted. A prospective protocol was used to study 31 victims of major trauma who underwent immediate surgical intervention. Victims of major head trauma were excluded and patients were selected at random over an 8-month period. At least two serial intraoperative blood samples were obtained at 15-min intervals via indwelling arterial catheters. A Hemochron model 801 coagulation monitor was used to measure the ACT. Of the 31 patients studied, 7 became clinically coagulopathic and 24 did not. The ACT measurements of coagulopathic and noncoagulopathic trauma patients were significantly different by multiple statistical comparisons. Both groups differed from normal, nontraumatized patients. The coagulopathic trauma patients had significantly elevated values when compared with other trauma patients or to normal values. We conclude that a low ACT reflects the initial hypercoagulability associated with major trauma and an elevated ACT is an objective indicator that the coagulation system reserve is near exhaustion. An elevated ACT may represent an indication for considering damage control maneuvers or more aggressive resuscitation.


American Journal of Surgery | 2000

Is regionalization of trauma care using telemedicine feasible and desirable

John A. Aucar; Thomas S. Granchi; Kathleen R. Liscum; Matthew J. Wall; Kenneth L. Mattox

BACKGROUND The judgement and skill of an experienced surgeon are crucial ingredients during trauma resuscitation, so that errors of omission, commission, and misprioritization can be avoided. Trauma represents a potential paradigm application for telemedicine owing to its ubiquitous and urgent nature and the limited availability of specialized care. METHODS A two-phase project was performed, using an Advanced Trauma Life Support (ATLS)-based evaluation tool. In phase I, we reviewed 24 videotaped trauma resuscitations on a single pass. Clinical data thus observed were compared with the clinical chart for agreement. In phase II, we performed real time, remote, initial evaluations of 17 trauma victims. RESULTS In phase I, 19 of 44 variables had agreement rates >90%, 10 had agreement rates between 70% and 90%. In phase II, agreement rates were similar to those in phase I, with improved accuracy in documenting initial and secondary vital signs and the secondary physical examination. CONCLUSION Remote evaluation of trauma victims is feasible. Accurate clinical data can be recorded, tasks delegated, and therapeutic measures advised using telemedicine. This can make expert trauma care available to hospitals without advanced trauma systems and potentially reduce cost, prevent unnecessary transfers, and promote early transfer when indicated.


Injury-international Journal of The Care of The Injured | 2004

Primary repair of blunt pancreatic transection.

John A. Aucar; Julian E. Losanoff

A 19-year-old female patient with blunt traumatic transection of the pancreas underwent successful primary repair of the pancreas and main pancreatic duct. A literature review revealed 14 previously reported such cases. Primary repair of the main pancreatic duct is feasible in selected patients. A wider experience will help to determine the methods role among such established surgical procedures as distal pancreatectomy, internal drainage, and minimally invasive transpapillary stent techniques.


American Journal of Surgery | 2003

Quantitative tracheal lavage versus bronchoscopic protected specimen brush for the diagnosis of nosocomial pneumonia in mechanically ventilated patients

John A. Aucar; Miguel Bongera; Jeffrey O. Phillips; Ravishankar Kamath; Michael H. Metzler


American Journal of Surgery | 2005

Economic modeling comparing trauma and general surgery reimbursement

John A. Aucar; Lanis L. Hicks

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Kenneth L. Mattox

Baylor College of Medicine

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Matthew J. Wall

Baylor College of Medicine

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Thomas S. Granchi

Baylor College of Medicine

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Charles C. Miller

University of Texas Health Science Center at Houston

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David Shin

Baylor College of Medicine

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Elizabeth Whitten

Baylor College of Medicine

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