SAGES video acquisition framework-analysis of available OR recording technologies by the SAGES AI task force

BACKGROUND

Surgical video recording provides the opportunity to acquire intraoperative data that can subsequently be used for a variety of quality improvement, research, and educational applications. Various recording devices are available for standard operating room camera systems. Some allow for collateral data acquisition including activities of the OR staff, kinematic measurements (motion of surgical instruments), and recording of the endoscopic video streams. Additional analysis through computer vision (CV), which allows software to understand and perform predictive tasks on images, can allow for automatic phase segmentation, instrument tracking, and derivative performance-geared metrics. With this survey, we summarize available surgical video acquisition technologies and associated performance analysis platforms.

METHODS

In an effort promoted by the SAGES Artificial Intelligence Task Force, we surveyed the available video recording technology companies. Of thirteen companies approached, nine were interviewed, each over an hour-long video conference. A standard set of 17 questions was administered. Questions spanned from data acquisition capacity, quality, and synchronization of video with other data, availability of analytic tools, privacy, and access.

RESULTS

Most platforms (89%) store video in full-HD (1080p) resolution at a frame rate of 30 fps. Most (67%) of available platforms store data in a Cloud-based databank as opposed to institutional hard drives. CV powered analysis is featured in some platforms: phase segmentation in 44% platforms, out of body blurring or tool tracking in 33%, and suture time in 11%. Kinematic data are provided by 22% and perfusion imaging in one device.

CONCLUSION

Video acquisition platforms on the market allow for in depth performance analysis through manual and automated review. Most of these devices will be integrated in upcoming robotic surgical platforms. Platform analytic supplementation, including CV, may allow for more refined performance analysis to surgeons and trainees. Most current AI features are related to phase segmentation, instrument tracking, and video blurring.

Standing electric scooter injuries: Impact on a community

BACKGROUND

This study investigates the impact of standing electric scooter-related injuries within an entire integrated hospital system.

METHODS

We performed a retrospective review of patients involved in standing electric scooter incidents presenting throughout an urban hospital network over a 10 month period. Rates of Google searches of scooter-related terms performed locally were used as a surrogate for ride frequency. Injury, mechanism, and cost data were analyzed.

RESULTS

Data on 248 patients were reviewed. Twenty-three (9%) were under 18 years old. Loss of balance was the most common cause of injury accounting for nearly half, while tripping over a scooter 14 (6%) affected the elderly disproportionately. Eight (3%) riders wore helmets. All TBI and closed head injuries occurred in unhelmeted patients. Most incidents occurred in the street, only one in a bicycle lane. Facilities costs were greater for patients under the influence of alcohol and marijuana.

CONCLUSION

Policies related to the use of mandated safety equipment, dedicated bicycle lanes, and the proper storage of empty vehicles should be further investigated.

Improved prediction of HIT in the SICU using an improved model of the Warkentin 4-T system: 3-T

BACKGROUND

The Warkentin 4-T scoring system for determining the pretest probability of heparin-induced thrombocytopenia (HIT) has been shown to be inaccurate in the ICU and does not take into account body mass index (BMI).

METHODS

Prospectively collected data on patients in the surgical and cardiac ICU between January 2007 and February 2016 who were presumed to have HIT by clinical suspicion were reviewed. Patients were categorized into 3 BMI groups and assigned scores: Normal weight, overweight, and obese. Multivariate analyses were used to identify independent predictors of HIT.

RESULTS

A total of 523 patients met inclusion criteria. Multivariate analysis showed that only BMI, Timing, and oTher variables were independently associated with HIT. This new 3-T model was better than a five-component model consisting of the entire 4-T scoring system plus BMI (AUC = 0.791).

CONCLUSIONS

Incorporating patient 'T'hickness into a pretest probability model along with platelet 'T'iming and the exclusion of o'T'her causes of thrombocytopenia yields a simplified "3-T" scoring system that has increased predictive accuracy in the ICU.

Direct Two-Minute Unassisted Breathing Evaluation (DTUBE) Is an Attractive Alternative to Longer Spontaneous Breathing Trials: A Prospective Observational Study

We sought to identify a simple bedside method to predict successful extubation outcomes that might be used during rounds. We hypothesized that a direct 2-minute unassisted breathing evaluation (DTUBE) could replace a longer spontaneous breathing trial (SBT). Data were prospectively collected on all patients endotracheally intubated for >48 hours nearing extubation in a tertiary center's mixed trauma/surgical intensive care unit from August 2012 to August 2013. The SBT was performed for at least 30 minutes at 40 per cent FiO2, PEEP 5, and PS 8. DTUBE was performed by physically disconnecting the intubated patient from the ventilator circuit for a 2-minute period of direct observation on room air. Successful extubation was defined freedom from ventilator for greater than 72 hours. Both SBT and DTUBE were performed 128 times, resulting in 90 extubations. The DTUBE correctly predicted success in 75/79 (94.9%) extubations versus 82/89 (92.1%) via SBT. No adverse effects were directly attributed to the DTUBE. The DTUBE is a rapid method of evaluating patients for extubation with prediction accuracy similar to the SBT.

Direct Two-Minute Unassisted Breathing Evaluation (DTUBE) is an Attractive Alternative to Longer Spontaneous Breathing Trials: A Prospective Observational Study

We sought to identify a simple bedside method to predict successful extubation outcomes that might be used during rounds. We hypothesized that a direct 2-minute unassisted breathing evaluation (DTUBE) could replace a longer spontaneous breathing trial (SBT). Data were pro-spectively collected on all patients endotracheally intubated for >48 hours nearing extubation in a tertiary center's mixed trauma/surgical intensive care unit from August 2012 to August 2013. The SBT was performed for at least 30 minutes at 40 per cent FiO2, PEEP 5, and PS 8. DTUBE was performed by physically disconnecting the intubated patient from the ventilator circuit for a 2-minute period of direct observation on room air. Successful extubation was defined freedom from ventilator for greater than 72 hours. Both SBTand DTUBE were performed 128 times, resulting in 90 extubations. The DTUBE correctly predicted success in 75/79 (94.9%) extubations versus 82/89 (92.1%) via SBT. No adverse effects were directly attributed to the DTUBE. The DTUBE is a rapid method of evaluating patients for extubation with prediction accuracy similar to the SBT.

Body mass index strongly impacts the diagnosis and incidence of heparin-induced thrombocytopenia in the surgical intensive care unit

BACKGROUND

The obese state has been linked to several immune-mediated conditions. Our objective was to examine the association of body mass index (BMI) with the diagnosis of heparin-induced thrombocytopenia (HIT).

METHODS

Prospectively collected data on patients in the surgical and cardiac intensive care unit suspected of having HIT between January 2007 and August 2014 were analyzed. Patients were categorized into five discrete BMI (kg/m) groups and compared. Data collected included Warkentin 4-T scores, antiplatelet factor 4 (anti-PF4OD) values, serotonin release assay values, and thromboembolic diseases. HIT positivity was defined as serotonin release assay value greater than 20%.

RESULTS

Of 304 patients meeting inclusion criteria, mean (SD) age was 62.1 (16.5) years, 59% were male, and mean (SD) BMI was 27 (6) kg/m. Thirty-six (12%) were positive for HIT. Incidence of HIT increased progressively with BMI (0%, 8%, 11%, 19%, 36%; p < 0.001). Compared with patients with normal BMI, patients with a BMI of 30 kg/m to 39.9 kg/m had a 200% increase in the odds for HIT (odds ratio [OR], 2.94; 95% confidence interval [CI], 1.20-7.54; p = 0.019), while patients with a BMI of 40 kg/m or greater had a 600% increase (OR, 6.98; 95% CI, 1.59-28.2; p = 0.012). After regression analysis, BMI remained an independent predictor of the development of HIT (adjusted OR per kg/m, 1.08; 95% CI, 1.02-1.14; p = 0.010). Anti-PF4OD values greater than or equal to 2.0 also increased with BMI (p < 0.001). In-hospital mortality increased significantly with BMI above normal (p = 0.026). Warkentin 4-T scores, deep venous thrombosis, pulmonary embolism, and stroke incidence did not correlate with changes in BMI.

CONCLUSION

Increasing BMI seems to be strongly associated with increased rates of HIT in intensive care unit patients. Obesity is an important new clinical variable for estimating the pretest probability of HIT, and patient "thickness" could be considered a fifth "T" of the 4-T scoring system. Additional biochemical work is indicated to decipher the role of obesity in this immune-mediated condition.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, level III.

Effect of Thoracentesis on Intubated Patients with Acute Lung Injury

Pleural effusions occur frequently in mechanically ventilated patients, but no consensus exists regarding the clinical benefit of effusion drainage. We sought to determine the impact of thoracentesis on gas exchange in patients with differing severities of acute lung injury (ALI). A retrospective analysis was conducted on therapeutic thoracenteses performed on intubated patients in an adult surgical intensive care unit of a tertiary center. Effusions judged by ultrasound to be 400 mL or larger were drained. Subjects were divided into groups based on their initial P:F ratios: normal >300, ALI 200 to 300, and acute respiratory distress syndrome (ARDS) <200. Baseline characteristics, physiologic variables, arterial blood gases, and ventilator settings before and after the intervention were analyzed. The primary end point was the change in measures of oxygenation. Significant improvements in P:F ratios (mean ± SD) were seen only in patients with ARDS (50.4 ± 38.5, P = 0.001) and ALI (90.6 ± 161.7, P = 0.022). Statistically significant improvement was observed in the pO2 (31.1, P = 0.005) and O2 saturation (4.1, P < 0.001) of the ARDS group. The volume of effusion removed did not correlate with changes in individual patient's oxygenation. These data support the role of therapeutic thoracentesis for intubated patients with abnormal P:F ratios.

Effect of Thoracentesis on Intubated Patients with Acute Lung Injury

Pleural effusions occur frequently in mechanically ventilated patients, but no consensus exists regarding the clinical benefit of effusion drainage. We sought to determine the impact of thoracentesis on gas exchange in patients with differing severities of acute lung injury (ALI). A retrospective analysis was conducted on therapeutic thoracenteses performed on intubated patients in an adult surgical intensive care unit of a tertiary center. Effusions judged by ultrasound to be 400 mL or larger were drained. Subjects were divided into groups based on their initial P:F ratios: normal >300, ALI 200 to 300, and acute respiratory distress syndrome (ARDS) <200. Baseline characteristics, physiologic variables, arterial blood gases, and ventilator settings before and after the intervention were analyzed. The primary end point was the change in measures of oxygenation. Significant improvements in P:F ratios (mean ± SD) were seen only in patients with ARDS (50.4 ± 38.5, P = 0.001) and ALI (90.6 ± 161.7, P = 0.022). Statistically significant improvement was observed in the pO2 (31.1, P = 0.005) and O2 saturation (4.1, P < 0.001) of the ARDS group. The volume of effusion removed did not correlate with changes in individual patient's oxygenation. These data support the role of therapeutic thoracentesis for intubated patients with abnormal P:F ratios.

Epidural Analgesia after Rib Fractures

Pain associated with rib fractures impairs respiratory function and increases pulmonary morbidity. The purpose of this study was to determine how epidural catheters alter mortality and complications in trauma patients. We performed a retrospective study involving adult blunt trauma patients with moderate-to-severe injuries from January 1, 2004 to December 31, 2013. During the 10-year period, 526 patients met the inclusion criteria; 43/526 (8%) patients had a catheter placed. Mean age of patients with epidural catheter (CATH) was higher compared with patients without epidural catheter (NOCATH) (54 vs 48 years, P = 0.021), Injury Severity Score was similar (26 CATH vs 27 NOCATH, P = 0.84), and CATH had higher mean rib fractures (7.4 vs 4.1, P < 0.001). Mortality was lower in CATH (0% vs 13%, P = 0.006). Deep vein thrombosis (DVT) rate was higher in CATH (12% vs. 5%, P = 0.036). After regression analysis, we found catheter placement to be a predictor for DVT (adjusted odds ratios 2.80, P = 0.036). Our center noted increased use of epidural catheters in patients who present with moderate-to-severe injuries. Patients with catheters were older and had a mean of 7.4 ribs fractured. The epidural cohort had longer hospital LOS and decreased mortality. In contrast to other studies, DVT rates were increased in patients who received epidural catheters.

Epidural Analgesia after Rib Fractures

Pain associated with rib fractures impairs respiratory function and increases pulmonary morbidity. The purpose of this study was to determine how epidural catheters alter mortality and complications in trauma patients. We performed a retrospective study involving adult blunt trauma patients with moderate-to-severe injuries from January 1, 2004 to December 31, 2013. During the 10-year period, 526 patients met the inclusion criteria; 43/526 (8%) patients had a catheter placed. Mean age of patients with epidural catheter (CATH) was higher compared with patients without epidural catheter (NOCATH) (54 vs 48 years, P = 0.021), Injury Severity Score was similar (26 CATH vs 27 NOCATH, P = 0.84), and CATH had higher mean rib fractures (7.4 vs 4.1, P < 0.001). Mortality was lower in CATH (0% vs 13%, P = 0.006). Deep vein thrombosis (DVT) rate was higher in CATH (12% vs. 5%, P = 0.036). After regression analysis, we found catheter placement to be a predictor for DVT (adjusted odds ratios 2.80, P = 0.036). Our center noted increased use of epidural catheters in patients who present with moderate-to-severe injuries. Patients with catheters were older and had a mean of 7.4 ribs fractured. The epidural cohort had longer hospital LOS and decreased mortality. In contrast to other studies, DVT rates were increased in patients who received epidural catheters.

Prospective evaluation of early propranolol after traumatic brain injury

BACKGROUND

Although beta-adrenergic receptor blockade may improve outcomes after traumatic brain injury (TBI), its early use is not routine. We hypothesize that judicious early low-dose propranolol after TBI (EPAT) will improve outcomes without altering bradycardia or hypotensive events.

METHODS

We conducted a prospective, observational study on all patients who presented with moderate-to-severe TBI from March 2010-August 2013. Ten initial patients did not receive propranolol (control). Subsequent patients received propranolol at 1-mg intravenous every 6 h starting within 12 h of intensive care unit (ICU) admission (EPAT) for a minimum of 48 h. Heart rate and blood pressure were recorded hourly for the first 72 h. Bradycardia and hypotensive events, mortality, and length of stay (LOS) were compared between cohorts to determine significant differences.

RESULTS

Thirty-eight patients were enrolled; 10 control and 28 EPAT. The two cohorts were similar when compared by gender, emergency department (ED) systolic blood pressure, ED heart rate, and mortality. ED Glasgow coma scale was lower (4.2 versus 10.7, P < 0.01) and injury severity score higher in control. EPAT patients received a mean of 10 ± 14 doses of propranolol. Hypotensive events were similar between cohorts, whereas bradycardia events were higher in control (5.8 versus 1.6, P = 0.05). ICU LOS (15.4 versus 30.4 d, P = 0.02) and hospital LOS (10 versus 19.1 d, P = 0.05) were lower in EPAT. Mortality rates were similar between groups (10% versus 10.7%, P = 0.9). The administration of propranolol led to no recorded complications.

CONCLUSIONS

Although bradycardia and hypotensive events occur early after TBI, low-dose intravenous propranolol does not increase their number or severity. Early use of propranolol after TBI appears to be safe and may be associated with decreased ICU and hospital LOS.

Postoperative infection risk after splenectomy: A prospective cohort study

INTRODUCTION

Splenectomy is associated with a life-long risk for overwhelming infections. The risk for early post-operative infectious complications following traumatic and elective splenectomy is, however, understudied. This investigation aimed to determine if splenectomy increases the risk for post-operative infections.

METHODS

This was a retrospective review of prospectively collected data on patients admitted to the surgical intensive care unit (SICU) between 1/2011 and 7/2013 investigating the risk for infectious complications in patients undergoing a splenectomy compared with those undergoing any other abdominal surgery.

RESULTS

During the 30-month study period, a total of 1884 patients were admitted to the SICU. Of those, 33 (2%) had a splenectomy and 493 (26%) had an abdominal surgery. The two groups were well balanced for age, APACHE IV score >20, and past medical history, including diabetes mellitus, cardiac history, renal failure or immunosuppression. Patients undergoing splenectomy were more likely to have sustained a traumatic injury (30% vs. 7%, p < 0.01). After adjustment, splenectomy was associated with increased risk for infectious complications (49% vs. 29%, Adjusted Odds Ratio (AOR) [95% CI]: 2.7 [1.3, 5.6], p = 0.01), including intra-abdominal abscess (9% vs. 3%, AOR [95% CI]: 4.3 [1.1, 16.2], p = 0.03). On a subgroup analysis, there were no differences between traumatic and elective splenectomy with regards to overall infectious complications (50% vs. 46%, p = 0.84), although, abdominal abscess developed only in those who had an elective splenectomy (0% vs. 12%, p = 0.55).

CONCLUSION

Splenectomy increases the risk for post-operative infectious complications. Further studies identifying strategies to decrease the associated morbidity are necessary.

Impact of deceased organ donor demographics and critical care end points on liver transplantation and graft survival rates

BACKGROUND

The criteria for organ acceptance remain inconsistent, which limits the ability to standardize critical care practices. We sought to examine predictors of liver graft use and survival to better guide the selection and management of potential organ donors.

STUDY DESIGN

A prospective observational study of all donors managed by the 8 organ procurement organizations in United Network for Organ Sharing Region 5 was conducted from July 2008 to March 2011. Critical care end points that reflect the normal hemodynamic, acid-base, respiratory, endocrine, and renal status of the donor were collected at 3 time points. Critical care and demographic data associated with liver transplantation and graft survival rates were first determined using univariate analyses, and then logistic regression was used to identify independent predictors of these two outcomes.

RESULTS

From 961 donors, 730 (76%) livers were transplanted and 694 (95%) were functioning after 74 ± 73 days of follow-up. After regression analysis, donor BMI (odds ratio [OR] = 0.94), male sex (OR = 1.89), glucose <150 mg/dL (OR = 1.97), lower dopamine dose (OR = 0.95), vasopressin use (OR = 1.95), and ejection fraction >50% (OR = 1.77) remained as independent predictors of liver use. Graft survival was associated with lower donor BMI (OR = 0.91) and sodium levels (OR = 0.95).

CONCLUSIONS

After controlling for donor age, sex, and BMI, both hemodynamic and endocrine critical care end points were associated with increased liver graft use. Both donor BMI and lower sodium levels during the course of donor management were independently predictive of improved graft survival. These results may help guide the management and selection of potential organ donors after neurologic determination of death.

Defining early trauma-induced coagulopathy using thromboelastography

Early trauma-induced coagulopathy (ETIC) is abnormal coagulation detected on presentation, but a clear description is lacking. We used thromboelastography (TEG) to characterize ETIC. Data were prospectively collected on high-acuity trauma activations at an urban Level I trauma center between July 2012 and May 2013. Patients with admission TEG before any blood transfusion were stratified by Injury Severity Score (ISS): mild (less than 16), moderate (16 to 24), severe (25 or greater). TEG parameters were compared between groups. ETIC was defined as any abnormality detected on TEG. Fifty-two patients were included; mean age was 49 years and mean time to the emergency department was 26 minutes. Mean ISS for the cohort was 17 with 28 patients in mild, eight in moderate, and 16 in severe. Glasgow Coma Score was lower and head Abbreviated Injury Scale was higher in severe (P < 0.001). Forty-three (83%) patients had an abnormal TEG. Shortened reaction (R) time was noted in 42 patients. There were no differences in any TEG parameters between the injury severity groups. Hyperfibrinolysis was detected in four (8%) patients. ETIC was present in over 80 per cent of high-acuity trauma activations irrespective of injury severity and characterized primarily by shortened R time, indicating ETIC is initially described by a hypercoagulable state as a result of thrombin generation.

Defining Early Trauma-induced Coagulopathy Using Thromboelastography

Early trauma-induced coagulopathy (ETIC) is abnormal coagulation detected on presentation, but a clear description is lacking. We used thromboelastography (TEG) to characterize ETIC. Data were prospectively collected on high-acuity trauma activations at an urban Level I trauma center between July 2012 and May 2013. Patients with admission TEG before any blood transfusion were stratified by Injury Severity Score (ISS): mild (less than 16), moderate (16 to 24), severe (25 or greater). TEG parameters were compared between groups. ETIC was defined as any abnormality detected on TEG. Fifty-two patients were included; mean age was 49 years and mean time to the emergency department was 26 minutes. Mean ISS for the cohort was 17 with 28 patients in mild, eight in moderate, and 16 in severe. Glasgow Coma Score was lower and head Abbreviated Injury Scale was higher in severe ( P < 0.001). Forty-three (83%) patients had an abnormal TEG. Shortened reaction (R) time was noted in 42 patients. There were no differences in any TEG parameters between the injury severity groups. Hyperfibrinolysis was detected in four (8%) patients. ETIC was present in over 80 per cent of high-acuity trauma activations irrespective of injury severity and characterized primarily by shortened R time, indicating ETIC is initially described by a hypercoagulable state as a result of thrombin generation.

Insurance type, not race, predicts mortality after pediatric trauma

BACKGROUND

In adult trauma, mortality varies with race and insurance status. In the elderly, insurance type has little impact on mortality after trauma and the influence of race is reduced. How race and insurance affect pediatric trauma requires further attention. We hypothesized that mortality after pediatric trauma is influenced by insurance type and not race.

METHODS

We reviewed all cases of blunt trauma in children ≤13 y requiring admission, using the National Trauma Data Bank Research Data Sets for 2007 and 2008. Exclusions included an Abbreviated Injury Score of 6 for any body region, dead on arrival, and missing data. Our primary outcome measure was in-hospital mortality.

RESULTS

We identified 831 Asian (1.2%), 10,592 black (15.5%), 45,173 white (66.2%), and 8498 Hispanic (12.5%) children, and 3161 children (4.6%) classified as other race. Mean age was 7.4 ± 4.5 y, 11.9% were uninsured, and overall in-hospital mortality was 1.4%. Multivariable modeling indicated that race was not associated with increased mortality (Asian versus white, adjusted odds ratio [AOR] 1.05, P = 0.88; black versus white, AOR 0.92, P = 0.42; Hispanic versus white, AOR 0.87, P = 0.26; and other race versus white, AOR 1.01, P = 0.96). In contrast, insurance status (any insurance versus no insurance, AOR 0.6, P < 0.01) and insurance type (private insurance versus no insurance, AOR 0.47, P < 0.01; Medicaid versus no insurance, 0.67, P < 0.01) predicted reduced mortality.

CONCLUSIONS

Insurance status and insurance type are important predictors of mortality after pediatric trauma while, in contrast, race is not.

Virtual reality applied to procedural testing: the next era

OBJECTIVE

To establish the construct validity of a virtual reality-based upper gastrointestinal endoscopy simulator as a tool for the skills training of residents.

SUMMARY BACKGROUND DATA

Previous studies have demonstrated the relevance of virtual reality training as an adjunct to traditional operating room learning for residents. The use of specific task trainers, which have the ability to objectively analyze and track user performance, has been shown to demonstrate improvements in performance over time. Using this off-line technology can lessen the financial and ethical concerns of using operative time to teach basic skills.

METHODS

Thirty-five residents and fellows from General Surgery and Gastrointestinal Medicine were recruited for this study. Their performance on virtual reality upper endoscopy tasks was analyzed by computer. Assessments were made on parameters such as time needed to finish the examination, completeness of the examination, and number of wall collisions. Subjective experiences were queried through questionnaires. Users were grouped according to their prior level of experience performing endoscopy.

RESULTS

Construct validation of this simulator was demonstrated. Performance on visualization and biopsy tasks varied directly with the subjects' prior experience level. Subjective responses indicated that novice and intermediate users felt the simulation to be a useful experience, and that they would use the equipment in their off time if it were available.

CONCLUSIONS

Virtual reality simulation may be a useful adjunct to traditional operating room experiences. Construct validity testing demonstrates the efficacy of this device. Similar objective methods of skills evaluation may be useful as part of a residency skills curriculum and as a means of procedural skills testing.

Identification of tyrosinase-related protein 2 as a tumor rejection antigen for the B16 melanoma

Recently, major advances have been made in the identification of antigens from human melanoma which are recognized by T cells. In spite of this, little is known about the optimal ways to use these antigens to treat patients with cancer. Progress in this area is likely to require accurate preclinical animal models, but the availability of such models has lagged behind developments in human tumor immunology. Whereas many of the identified human melanoma antigens are normal tissue differentiation proteins, analogous murine tumor antigens have not yet been identified. In this paper we identify a normal tissue differentiation antigen, tyrosinase-related protein 2 (TRP-2), expressed by the murine B16 melanoma which was found by screening a cDNA library from B16 with tumor-reactive cytotoxic T lymphocytes (CTL). A peptide conforming to the predicted MHC class I H2-Kb binding motif, TRP-2181-188, was identified as the major reactive epitope within TRP-2 recognized by these anti-B16 CTLs. By site-directed mutagenesis, it was shown that alteration of this epitope eliminated recognition of TRP-2. It was further demonstrated that a CTL line raised from splenocytes by repeated stimulation in vitro with this peptide could recognize B16 tumor and was therapeutic against 3-d-old established pulmonary metastases. The use of TRP-2 in a preclinical model of tumor immunotherapy may be helpful in suggesting optimal vaccination strategies for cancer therapy in patients.

Tracheoesophageal fistula associated with Barrett's ulcer: the importance of reflux control

A benign tracheoesophageal fistula occurring as a complication of Barrett's ulcerative esophagitis is described. Surgical control of gastroesophageal reflux resulted in healing of the fistula, obviating the need for a resective procedure or esophageal exclusion. Although Barrett's ulcer has been reported as a cause of acquired esophagorespiratory fistula, to our knowledge, the important role of reflux control in the management of this difficult problem has not been discussed.