Overproduction of endothelin-1 impairs glucose tolerance but does not promote visceral adipose tissue inflammation or limit metabolic adaptations to exercise

Endothelin-1 (ET-1) is a potent vasoconstrictor and proinflammatory peptide that is upregulated in obesity. Herein, we tested the hypothesis that ET-1 signaling promotes visceral adipose tissue (AT) inflammation and disrupts glucose homeostasis. We also tested if reduced ET-1 is a required mechanism by which exercise ameliorates AT inflammation and improves glycemic control in obesity. We found that 1) diet-induced obesity, AT inflammation, and glycemic dysregulation were not accompanied by significantly increased levels of ET-1 in AT or circulation in wild-type mice and that endothelial overexpression of ET-1 and consequently increased ET-1 levels did not cause AT inflammation yet impaired glucose tolerance; 2) reduced AT inflammation and improved glucose tolerance with voluntary wheel running was not associated with decreased levels of ET-1 in AT or circulation in obese mice nor did endothelial overexpression of ET-1 impede such exercise-induced metabolic adaptations; 3) chronic pharmacological blockade of ET-1 receptors did not suppress AT inflammation in obese mice but improved glucose tolerance; and 4) in a cohort of human subjects with a wide range of body mass indexes, ET-1 levels in AT, or circulation were not correlated with markers of inflammation in AT. In aggregate, we conclude that ET-1 signaling is not implicated in the development of visceral AT inflammation but promotes glucose intolerance, thus representing an important therapeutic target for glycemic dysregulation in conditions characterized by hyperendothelinemia. Furthermore, we show that the salutary effects of exercise on AT and systemic metabolic function are not contingent on the suppression of ET-1 signaling.

Characterizing information decay in patient handoffs

OBJECTIVE

The purpose of this study was to analyze the decay of information with multiple sequential patient handoff reports given by third-year medical students who have not had standardized patient handoff training.

METHODS

We examine the information decay of quantitative parameters included in 2 different simulated patient history and physical handoffs conducted among third-year medical students. Both student self-surveys and third party observer surveys tracked accuracy of information. A total of 93 students were surveyed for the first patient scenario and 103 students were surveyed for second patient scenario. Survey data were aggregated into 2 separate spreadsheets, one for each patient scenario tested. A total of 16 data points pertaining to the checklist were analyzed for common trends in handoff accuracy and information decay.

RESULTS

Quantitative analysis of information passed between handoffs showed that between the 2 case scenarios, there was a consistent loss of information between one presenter to the next. Overall, 33% of information was lost between the first and third handoffs. Within the progression of individual handoffs, a narrative decay was demonstrated. There was a regression in handoff accuracy, trending down to an average of only 45% of information being passed on successfully by the time each presenter reached the last piece of information in their patient presentation. When examining the survey data points that had greater than an 80% success rate of being included in the handoffs, there appeared to be no correlation between their inherent qualities.

CONCLUSIONS

This study showed there is a significant decrease in accuracy of information during sequential patient handoff exercises. The information decay may be a result of time, memory, or relevance of the information to the student. Future studies incorporating teaching effective handoffs early in the clinical curriculum would be an area of future research.

Methylene blue: a simple marker for intraoperative detection of gastroduodenal perforations during laparoscopic pyloromyotomy

INTRODUCTION

We studied the feasibility of using methylene blue (MB) as a marker to detect mucosal perforations during laparoscopic pyloromyotomy using in vitro and in vivo animal models.

MATERIALS AND METHODS

MB was initially tested in pig stomachs in vitro. Information gathered from these experiments was then used to test the marker during experimental live piglet laparoscopic surgery.

RESULTS

MB stained the gastric mucosa blue; this tint could be seen through the intact mucosal layer exposed via myotomy. Dye extravasation was seen during laparoscopic surgery with mucosal perforations of 1.2 mm and greater with or without air insufflation of the stomach. Air extravasation was seen with perforations of 2.0 mm and greater.

CONCLUSION

Full strength 1% MB dye instilled into the gastric lumen can potentially be used as a marker for detection of mucosal perforations of 1.2 mm or greater during laparoscopic pyloromyotomy.

Robotic versus laparoscopic colectomy

BACKGROUND

This study compared the experience and cost of the DaVinci Robotic system and laparoscopy for colon resections.

METHODS

For this study, 30 consecutive robotic and 27 consecutive laparoscopic colectomies were divided into right and sigmoid colectomies for analysis. Comparisons included indications for surgery, gender, age, body mass index (BMI), estimated blood loss (EBL), length of operation, length of hospital stay (LOS), complications, operating room (OR) cost, OR personnel cost, OR supply cost, OR time cost, and total hospital cost.

RESULTS

The comparison groups were similar in indications for surgery, gender, age, BMI, EBL, and LOS. The right colectomies included 17 robotic and 15 laparoscopic procedures. An intracorporeal anastomosis was performed in the robotic cases, and an extracorporeal anastomosis was performed in the laparoscopic cases. The total case time was 218.9 min for the robotic and 169.2 min for the laparoscopic procedures (p = 0.002). The total hospital cost was $9,255 for the robotic and $8,073 for the laparoscopic procedures (p = 0.430). The total OR cost was $5,823 for the robotic and $4,339 for the laparoscopic procedures (p < 0.000). The sigmoid colectomies included 13 robotic and 12 laparoscopic procedures. The robotic and laparoscopic cases were managed in similar sequence. The total case time was 225.2 min for the robotic and 199.4 min for the laparoscopic procedures (p = 0.128). The total hospital cost was $12,335 for the robotic and $10,697 for the laparoscopic procedures (p = 0.735). The total OR cost was $6,059 for the robotic and $4,974 for the laparoscopic procedures (p = 0.068). The complications in the robotic groups were more numerous, but were not attributable to equipment.

CONCLUSIONS

The comparison groups were similar. The robotic cases were significantly longer for right colectomies because of the intracorporeal anastomosis instead of the extracorporeal anastomosis performed in the laparoscopy cases. Every cost category was higher for the robotic cases. The right colectomies showed significant increases in total OR cost, OR personnel cost, OR supply cost, and OR time cost. The sigmoid colectomies had significant increases in OR personnel cost and OR supply cost. The total hospital cost was higher for the robotic groups, but the difference was not statistically significant.

Telerobotic surgery for right and sigmoid colectomies: 30 consecutive cases

BACKGROUND

This study aimed to evaluate the feasibility of using a robotic assistant for colon resections. This report describes the experience, advantages, and disadvantages of using the DaVinci system for a colectomy on the basis of 30 consecutive cases managed by a minimally invasive surgery fellowship-trained surgeon.

METHODS

Data were prospectively collected on 30 consecutive colectomies performed using the DaVinci system from September 2002 to March 2005.

RESULTS

A total of 13 sigmoid colectomies with splenic flexure mobilization and 17 right colectomies were performed for 14 men and 16 women. The preoperative diagnoses for the procedures were cancer (n = 5), diverticulitis (n = 8), polyps (n = 16), and carcinoid (n = 1). The right colectomies required 29.7 +/- 6.7 min (range, 22-44 min) for the port setup, 177.1 +/- 50.6 min (range, 103-306 min) for the robot, and 218.9 +/- 44.6 min (range, 167-340 min) for the total case. The length of stay was 5.2 +/- 5.8 days (range, 2-27 days). The robot portion was 80.9% of the total case time. The sigmoid colectomies required 30.1 +/- 9.6 min (range, 15-50 min) for the port setup, 103.2 +/- 29.4 min (range, 69-165 min) for the robot, and 225.2 +/- 37.1 min (range, 147-283 min) for the total case. The hospital length of stay was 6.0 +/- 7.3 days (range, 3-30 days). The robot portion was 45.8% of the total case time. Six complications occurred: left hip paresthesia, cecal injury, anastomotic leak, patient slipped from the operating table after the robotic portion of the case, transverse colon injury, and return of a patient to the office with urinary retention. Two sigmoid colectomies were converted to laparotomy. The specific advantages and disadvantages of using the DaVinci system for colectomies are discussed.

CONCLUSIONS

The 30 consecutive cases demonstrated the technical feasibility of using the DaVinci system for a colectomy. The longevity of the DaVinci system's use for colectomy will be determined by comparison of its cost and outcomes with those for conventional laparoscopic colectomy.