Systematic Review of Preoperative Risk Discussion in Practice

BACKGROUND

Informed consent is an ethical imperative of surgical practice. This requires effective communication of procedural risks to patients and is learned during residency. No systematic review has yet examined current risk disclosure. This systematic review aims to use existing published information to assess preoperative provision of risk information by surgeons.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses as a guide, a standardized search in Ovid MEDLINE, Embase, CINHAL, and PubMed was performed. Three reviewers performed the study screening, with 2-reviewer consensus required at each stage. Studies containing objective information concerning preoperative risk provision in adult surgical patients were selected for inclusion. Studies exclusively addressing interventions for pediatric patients or trauma were excluded, as were studies addressing risks of anesthesia.

RESULTS

The initial search returned 12,988 papers after deduplication, 33 of which met inclusion criteria. These studies primarily evaluated consent through surveys of providers, record reviews and consent recordings. The most ubiquitous finding of all study types was high levels of intra-surgeon variation in what risk information is provided to patients preoperatively. Studies recording consents found the lowest rates of risk disclosure. Studies using multiple forms of investigation corroborated this, finding disparity between verbally provided information vs chart documentation.

CONCLUSIONS

The wide variance in what information is provided to patients preoperatively inhibits the realization of the ethical and practical components of informed consent. The findings of this review indicate that significant opportunities exist for practice improvement. Future development of surgical communication tools and techniques should emphasize standardizing what risks are shared with patients.

Does adding clinical data to administrative data improve agreement among hospital quality measures?

BACKGROUND

Hospital performance measures based on patient mortality and readmission have indicated modest rates of agreement. We examined if combining clinical data on laboratory tests and vital signs with administrative data leads to improved agreement with each other, and with other measures of hospital performance in the nation's largest integrated health care system.

METHODS

We used patient-level administrative and clinical data, and hospital-level data on quality indicators, for 2007-2010 from the Veterans Health Administration (VA). For patients admitted for acute myocardial infarction (AMI), heart failure (HF) and pneumonia we examined changes in hospital performance on 30-d mortality and 30-d readmission rates as a result of adding clinical data to administrative data. We evaluated whether this enhancement yielded improved measures of hospital quality, based on concordance with other hospital quality indicators.

RESULTS

For 30-d mortality, data enhancement improved model performance, and significantly changed hospital performance profiles; for 30-d readmission, the impact was modest. Concordance between enhanced measures of both outcomes, and with other hospital quality measures - including Joint Commission process measures, VA Surgical Quality Improvement Program (VASQIP) mortality and morbidity, and case volume - remained poor.

CONCLUSIONS

Adding laboratory tests and vital signs to measure hospital performance on mortality and readmission did not improve the poor rates of agreement across hospital quality indicators in the VA.

INTERPRETATION

Efforts to improve risk adjustment models should continue; however, evidence of validation should precede their use as reliable measures of quality.

How pooling fragmented healthcare encounter data affects hospital profiling

OBJECTIVES

People receiving healthcare from multiple payers (eg, Medicare and the Veterans Health Administration [VA]) have fragmented health records. How the use of more complete data affects hospital profiling has not been examined.

STUDY DESIGN

Retrospective cohort study.

METHODS

We examined 30-day mortality following acute myocardial infarction at 104 VA hospitals for veterans 66 years and older from 2006 through 2010 who were also Medicare beneficiaries. Using VA-only data versus combined VA/Medicare data, we calculated 2 risk-standardized mortality rates (RSMRs): 1 based on observed mortality (O/E) and the other from CMS' Hospital Compare program, based on model-predicted mortality (P/E). We also categorized hospital outlier status based on RSMR relative to overall VA mortality: average, better than average, and worse than average. We tested whether hospitals whose patients received more of their care through Medicare would look relatively better when including those data in risk adjustment, rather than including VA data alone.

RESULTS

Thirty-day mortality was 14.8%. Adding Medicare data caused both RSMR measures to significantly increase in about half the hospitals and decrease in the other half. O/E RSMR increased in 53 hospitals, on average, by 2.2%, and decreased in 51 hospitals by -2.6%. P/E RSMR increased, on average, by 1.2% in 56 hospitals, and decreased in the others by -1.3%. Outlier designation changed for 4 hospitals using O/E measure, but for no hospitals using P/E measure.

CONCLUSIONS

VA hospitals vary in their patients' use of Medicare-covered care and completeness of health records based on VA data alone. Using combined VA/Medicare data provides modestly different hospital profiles compared with those using VA-alone data.

Inguinoscrotal bladder hernias: report of a series and review of the literature

Bladder involvement occurs in 1%-4% of cases of inguinal hernias. Among obese men aged 50 to 70, the incidence may reach 10%.1,2 The diagnosis of bladder involvement is often difficult to delineate at the time of presentation and may only become apparent at the time of herniorrhaphy. Surgical management pertaining to the approach, repair and potential need for bladder resection may challenge the surgeon. We report a series of 4 cases of large inguinoscrotal bladder hernias and provide a literature review. Our goal is to highlight the clinical presentation and the decisive issues surrounding the diagnosis and management of this condition.

Assessing the Quality of Surgical Care

Because of better educated patients, more demanding payers, and regulatory agencies, safety and quality have become prominent criteria for evaluating surgical care. Providers are increasingly asked to document these areas, and patients are using this documentation to select surgeons and hospitals. Payers are using the data to direct patients to providers, and potentially to adjust reimbursement rates. Therefore, health care policy makers, health service researchers, and others are aggressively developing and implementing quality indicators for surgical practice. Given the complex interplay of structure, process, and outcomes, assessment of surgical quality presents a daunting task. We must firmly establish the links between these elements to validate current and future metrics, while engendering "buy-in'' on the part of surgeons.

Relationship of Processes and Structures of Care in General Surgery to Postoperative Outcomes: A Descriptive Analysis

BACKGROUND

The systematic collection of quantitative data on structures and processes from surgical services participating in the National Surgical Quality Improvement Program (NSQIP) has not been a focus to date. Efficient collection of useful measures of structures and processes may improve understanding of surgical outcomes and strategies for improving the quality of surgical care, as NSQIP continues to expand. The purpose of this article was to describe results of a quantitative survey designed to measure surgical care structures and processes within NSQIP sites.

STUDY DESIGN

A cross-sectional survey was mailed to 123 Department of Veteran Affairs (VA) and 14 private sector sites participating in the Agency for Healthcare Research and Quality (AHRQ)-funded Patient Safety in Surgery (PSS) Study. The survey included questions about organizational structures and processes of preoperative, intraoperative, and postoperative general surgical care services. For this study, we included only data from 90 VA sites that returned a survey (73% response rate). We used descriptive statistics and examined the bivariate association of structures and processes items or scales with risk-adjusted observed-to-expected (O/E) ratios of surgical morbidity and mortality.

RESULTS

Examination of frequency or means and standard deviations of items and scales revealed substantial variation in the structures and processes of surgical care services in participating VA sites, with correlation analyses demonstrating that, of 35 process and structure variables, there was a statistically significant relationship with the hospital's observed-to-expected ratio for 14 variables for morbidity, but only 4 variables for mortality.

CONCLUSIONS

This descriptive analysis provides support for the potential importance of measuring organizational structures and processes of care in addition to risk-adjusted morbidity and mortality.

Relationship of Processes and Structures of Care in General Surgery to Postoperative Outcomes: A Qualitative Analysis

BACKGROUND

With increased focus on improving surgical care quality, understanding structures and processes that influence surgical care is timely and important, as is more precise specification of these through improved measurement.

STUDY DESIGN

We conducted a qualitative study to help design a quantitative survey of structures and processes of surgical care. We audiotaped 44 face-to-face interviews with surgical care leaders and other diverse members of the surgical care team from 6 hospitals (two Veterans Affairs, four private sector). Qualitative interviews were transcribed and analyzed to identify common structures and processes mentioned by interviewees to include on a quantitative survey and to develop a rich description of salient themes on indicators of effective surgical care services and surgical care teams.

RESULTS

Qualitative analyses of transcripts resulted in detailed descriptions of structures and processes of surgical care services that affected surgical care team performance--and how particular structures led to effective and ineffective processes that impacted quality and outcomes of surgical care. Communication and care coordination were most frequently mentioned as essential to effective surgical care services and teams. Informants also described other influences on surgical quality and outcomes, such as staffing, the role of residents, and team composition and continuity.

CONCLUSIONS

Surgical care team members reinforced the importance of understanding surgical care processes and structures to improve both quality and outcomes of surgical care. The analysis of interviews helped the study team identify potential measures of structures and processes to include in our quantitative survey.

Comparison of Risk-Adjusted 30-Day Postoperative Mortality and Morbidity in Department of Veterans Affairs Hospitals and Selected University Medical Centers: General Surgical Operations in Men

BACKGROUND

We used data from the Patient Safety in Surgery Study to compare patient populations, operative characteristics, and unadjusted and risk-adjusted 30-day postoperative mortality and morbidity between the Veterans Affairs (VA) (n = 94,098) and private (n = 18,399) sectors for general surgery operations in men.

STUDY DESIGN

This is a prospective cohort study. Trained nurses collected preoperative risk factors, operative variables, and 30-day postoperative mortality and morbidity outcomes in male patients undergoing major general surgery operations at 128 VA medical centers and 14 university medical centers from October 1, 2001, to September 30, 2004. Multiple logistic regression analysis was used to identify preoperative predictors of postoperative mortality and morbidity. An indicator variable for VA versus private-sector medical center was added to the model to determine if risk-adjusted outcomes were significantly different in the two systems.

RESULTS

The unadjusted 30-day mortality rate was higher in the VA compared with the private sector (2.62% versus 2.03%, p = 0.0002); unadjusted morbidity rate was lower in the VA compared with the private sector (12.24% versus 13.99%, p < 0.0001). After risk adjustment, odds ratio for mortality for the VA versus private sector was 1.23 (95% CI, 1.08-1.41). For morbidity after risk adjustment, the indicator variable for health-care system just missed statistical significance (p = 0.0585). Thirty-day postoperative mortality was comparable in the VA and private sector for very common operations but was higher in the VA for less common, more complex operations.

CONCLUSIONS

In general surgery operations in men, the VA appeared to have a higher risk-adjusted mortality rate compared with the private sector, but differences in mortality ascertainment in the two sectors might account for some of this effect. The higher mortality in the VA could be the result of higher mortality in the less common, more complex operations. There is a trend toward lower risk-adjusted morbidity in the VA compared with the private sector.

The Patient Safety in Surgery Study: Background, Study Design, and Patient Populations

BACKGROUND

The purpose of this article is to describe the background, design, and patient populations of the Patient Safety in Surgery Study, as a preliminary to the articles in this journal that will report the results of the Study.

STUDY DESIGN

The Patient Safety in Surgery Study was a prospective cohort study. Trained nurses collected preoperative risk factors, operative variables, and 30-day postoperative mortality and morbidity outcomes in patients undergoing major general and vascular operations at 128 Veterans Affairs (VA) medical centers and 14 selected university medical centers between October 1, 2001 and September 30, 2004. An Internet-based data collection system was used to input data from the different private medical centers. Semiannual feedback of observed to expected mortality and morbidity ratios was provided to the participating medical centers.

RESULTS

During the 3-year study, total accrual in general surgery was 145,618 patients, including 68.5% from the VA and 31.5% from the private sector. Accrual in vascular surgery totaled 39,225 patients, including 77.8% from the VA and 22.2% from the private sector. VA patients were older and included a larger proportion of male patients and African Americans and Hispanics. The VA population included more inguinal, umbilical, and ventral hernia repairs, although the private-sector population included more thyroid and parathyroid, appendectomy, and operations for breast cancer. Preoperative comorbidities were similar in the two populations, but the rates of comorbidities were higher in the VA. American Society of Anesthesiologists classification tended to be higher in the VA.

CONCLUSIONS

The National Surgical Quality Improvement Program methodology was successfully implemented in the 14 university medical centers. The data from the study provided the basis for the articles in this issue of the Journal of the American College of Surgeons.

Comparison of Risk-Adjusted 30-Day Postoperative Mortality and Morbidity in Department of Veterans Affairs Hospitals and Selected University Medical Centers: General Surgical Operations in Women

BACKGROUND

In 1985, Congress mandated that the Department of Veterans Affairs (VA) compare its risk-adjusted surgical results with those in the private sector. The National Surgical Quality Improvement Program was developed as a result, in the VA system, and subsequently trialed in 14 university medical centers in the private sector. This report examines the results of the comparison between patient characteristics and outcomes of female general surgical patients in the two health care environments.

STUDY DESIGN

Preoperative patient characteristics and laboratory variables, operative variables, and unadjusted postoperative outcomes were compared between VA and the private sector populations. In addition, stepwise logistic regression models were developed for 30-day postoperative mortality and morbidity. Finally, the effect of being treated in a VA or private sector hospital was assessed by adding an indicator variable to the models and testing it for statistical significance.

RESULTS

Data from 5,157 female general surgical VA patients who underwent eligible procedures were compared with those from 27,467 patients in the private sector. Unadjusted 30-day mortality was virtually identical in the two groups (1.3%). The unadjusted morbidity rate was slightly, but notably, higher in the private sector (10.9%) as compared with that observed in the VA (8.5%, p < 0.0001). Predictive models were generated for mortality and morbidity combining both groups; top variables in these models were similar to those described previously in the National Surgical Quality Improvement Program. The indicator variable for system of care (VA versus private sector) was not statistically significant in the mortality model, but substantially favored the VA in the morbidity model (odds ratio=0.80, 95% CI=0.71, 0.90).

CONCLUSIONS

The data demonstrate that in female general surgical patients, risk-adjusted mortality rates are comparable in the VA and the private sector, but risk-adjusted morbidity is higher in the private sector. Rates of urinary tract infections in the two populations may account for much of the latter difference.

Reducing surgical site infections through a multidisciplinary computerized process for preoperative prophylactic antibiotic administration

BACKGROUND

Surgical site infections (SSIs) result in significant postoperative morbidity and mortality. Although many of these infections can be prevented by timely administration of preoperative antibiotics, data suggest that many patients do not receive such therapy.

METHODS

A multidisciplinary team was convened that reviewed published guidelines, made antibiotic recommendations, and addressed administration issues. Responsibility for antibiotic administration was shifted from preoperative nursing staff to the anesthetist. Electronic quick orders were developed to encourage appropriate antibiotic selection and simplify order creation.

RESULTS

Timely administration of preoperative antibiotics improved from 51% to 98% from February 2005 to February 2006. Appropriate antibiotic administered improved from 78% to 94%. The clean wound infection rate decreased from 2.7% to 1.4% over the same time period.

CONCLUSION

A multidisciplinary approach to prophylactic antibiotic use, including computer-guided decision support, facilitates appropriate preoperative antibiotic use, resulting in a significant decrease in surgical wound infections.

Informed Versus Uninformed Consent for Prostate Surgery: The Value of Electronic Consents

PURPOSE

We evaluated the documentation of informed consent for 2 common prostate operations using current, conventional, paper based consent forms. Based on the results of the review the conventional paper based consent system was replaced with a new, standardized electronic consent system.

MATERIALS AND METHODS

We retrospectively reviewed the consent forms obtained for transurethral resection of the prostate and radical prostatectomy procedures during the 6-year period 1995 to 2000 at Atlanta Veterans Affairs Medical Center. Analysis focused on the basic elements of informed consent, including a description of the proposed treatment, and the purpose, benefits, risks and alternatives. Based on these findings we standardized the procedure specific information contained in consent forms and stored it electronically in a central network accessible to all urology providers throughout the medical center.

RESULTS

Of the 222 total procedures 204 consent forms were available for review. Senior residents, junior residents and physician assistants obtained consent for 42.2%, 30.9% and 25.5% of procedures, respectively. Information on the purpose and benefits of treatment was missing in 4.4% of cases and deficient in 22.6%. General or procedure specific risks were documented inconsistently in 0% to 96% of cases. Alternative treatment options were missing in 49% of the consent forms and they were significantly deficient in the remaining 51%. Prognosis and surgical risks were documented variably for each procedure. For example, in the radical prostatectomy group 79 patients (88.8%) had appropriate documentation regarding the potential for significant blood loss and yet only 23 (25.8%) had documented consent for blood transfusion. Following the implementation of a new standardized electronic consent program 96.1% of the patients surveyed preferred the new system.

CONCLUSIONS

Conventional nonstandardized consent forms have significant deficiencies and errors. The new system of electronic informed consent is standardized, legible and understandable, and it assists providers in fully informing patients about the treatment, risks, benefits and alternative therapies, thereby supporting ethical and legal standards, and improving the quality of care. In our opinion standardized electronic informed consent should be the new standard of care.

Evidence-based outcome data after hernia surgery: A possible role for the National Surgical Quality Improvement Program

Since its inception in 1994, the National Surgical Quality Improvement Program (NSQIP) has been used to compare the performance of all Veterans Administration (VA) hospitals offering major surgical procedures. The program's outcome data are used to identify areas of both excellent and poor performance. The data can also be used to focus on specific procedures, especially high frequency operations such as inguinal herniorrhaphy. Following several successful feasibility studies, the NSQIP has been adopted by the American College of Surgeons (ACS) and is being offered nationwide in the non-VA sector. Given the profound decrease in operative mortality and morbidity seen within the VA, it seems realistic to expect similar improvements in global-and procedure specific-surgical outcomes within the non-VA sector.

Evaluating alternative risk-adjustment strategies for surgery

BACKGROUND

Comparison of institutional health care outcomes requires risk adjustment. Risk-adjustment methodology may influence the results of such comparisons.

METHODS

We compared 3 risk-adjustment methodologies used to assess the quality of surgical care. Nurse reviewers abstracted data from a continuous sample of 2,167 surgical patients at 3 academic institutions. One risk adjustor was based on medical record data (National Surgical Quality Improvement Program [NSQIP]) whereas the other 2, the DxCG and Charlson Comorbidity Index (CCI), primarily used International Classification of Disease-9 (ICD-9) codes. Risk-assessment scores from the 3 systems were compared with each other and with mortality.

RESULTS

Substantial disagreement was found in the risk assessment calculated by the 3 methodologies. Although there was a weak association between the CCI and DxCG, neither correlated well with the NSQIP. The NSQIP was best able to predict mortality, followed by the DxCG and CCI.

CONCLUSION

In surgical patients, different risk-adjustment methodologies afford divergent estimates of mortality risk.

Endoscopic Retrograde Cholangiopancreatography in Chronic Pancreatitis

Endoscopic retrograde cholangiopancreatography (ERCP) plays an important diagnostic and therapeutic role in the management of chronic pancreatitis. New techniques are being developed which should further improve outcomes of endoscopic intervention. The ultimate role of these therapeutic interventions for chronic pancreatitis awaits prospective randomized data demonstrating their efficacy and safety in comparison to surgery. Until such time, these often difficult techniques should be performed by experienced endoscopists with significant experience in pancreatic disease, ideally within the context of controlled clinical trials.

Angiotensin II evokes calcium-mediated signaling events in isolated dog pancreatic epithelial cells

INTRODUCTION

Calcium-activated chloride conductance has been identified in normal pancreatic duct cells. Recent in vitro evidence suggests that angiotensin II (AngII) stimulates pancreatic secretion in both cystic fibrosis (CFPAC) and transformed pancreatic cells.

AIMS

To investigate calcium-mediated stimulatory effects of AngII in both nontransformed dog pancreatic duct epithelial (DPDE) and CFPAC cells.

METHODS

Western blots were performed in both cells seeking AngII receptors. In additional studies, DPDE and CFPAC cells were grown on vitrogen-coated glass cover slips and loaded with Indo-1-AM dye. Cells were placed in a confocal microscope's perfusion chamber and perfused with 100 microM AngII or ATP (control). Cells were excited with UV light, and intracellular calcium ([Ca+2]i) was read using fluorescence emission at 405 and 530 nm. Finally, single channels in the DPDE cells were examined using cell-attached patch clamps. Current amplitude histograms provided estimates of the conductance and open probability of channels.

RESULTS

Western blots demonstrated presence of both AT and AT AngII receptors in DPDE and CFPAC cells; the density of AT receptors appeared lower than that of AT receptors. Basal intracellular calcium concentrations did not differ between DPDE (109 +/- 11 nM) and CFPAC (103 +/- 8 nM) cells. AngII significantly increased measured intracellular calcium concentrations in both DPDE (909 +/- 98 nM) and CFPAC (879 +/- 207 nM) cells, as did ATP (DPDE = 1722 +/- 228 nM; CFPAC = 1522 +/- 245 nM). In the patch clamp studies, a variety of different channels were observed; they appeared to be an 11pS nonselective cation (NSC) channel, a 4.6pS Na+ channel, a 3pS anion channel, and an 8pS chloride channel. The latter channel had characteristics similar to cystic fibrosis transmembrane conductance regulator (CFTR). Apical or basolateral application of AngII activated both the 11pS NSC and the 3pS channels.

CONCLUSION

In nontransformed DPDE and CFPAC cells, specific AngII receptors mediate increases in [Ca ]. The latter effect of AngII may elicit activation of calcium-mediated chloride channels, suggesting a role for AngII as an alternative mediator of pancreatic ductal secretion.

The National Surgical Quality Improvement Program in non-veterans administration hospitals: initial demonstration of feasibility

OBJECTIVE

To assess the feasibility of implementing the National Surgical Quality Improvement Program (NSQIP) methodology in non-VA hospitals.

SUMMARY BACKGROUND DATA

Using data adjusted for patient preoperative risk, the NSQIP compares the performance of all VA hospitals performing major surgery and anonymously compares these hospitals using the ratio of observed to expected adverse events. These results are provided to each hospital and used to identify areas for improvement. Since the NSQIP's inception in 1994, the VA has reported consistent improvements in all surgery performance measures. Given the success of the NSQIP within the VA, as well as the lack of a comparable system in non-VA hospitals, this pilot study was undertaken to test the applicability of the NSQIP models and methodology in the nonfederal sector.

METHODS

Beginning in 1999, three academic medical centers (Emory University, Atlanta, GA; University of Michigan, Ann Arbor, MI; University of Kentucky, Lexington, KY) volunteered the time of a dedicated surgical nurse reviewer who was trained in NSQIP methodology. At each academic center, these nurse reviewers used NSQIP protocols to abstract clinical data from general surgery and vascular surgery patients. Data were manually collected and then transmitted via the Internet to a secure web site developed by the NSQIP. These data were compared to the data for general and vascular surgery patients collected during a concurrent time period (10/99 to 9/00) within the VA by the NSQIP. Logistic regression models were developed for both non-VA and VA hospital data. To assess the models' predictive values, C-indices (0.5 = no prediction; 1.0 = perfect prediction) were calculated after applying the models to the non-VA as well as the VA databases.

RESULTS

Data from 2,747 (general surgery 2,251; vascular surgery 496) non-VA hospital cases were compared to data from 41,360 (general surgery 31,393; vascular surgery 9,967) VA cases. The bivariate relationships between individual risk factors and 30-day mortality or morbidity were similar in the non-VA and VA patient populations for over 66% of the risk variables. C-indices of 0.942 (general surgery), 0.915 (vascular surgery), and 0.934 (general plus vascular surgery) were obtained following application of the VA NSQIP mortality model to the non-VA patient data. Lower C-indices (0.778, general surgery; 0.638, vascular surgery; 0.760, general plus vascular surgery) were obtained following application of the VA NSQIP morbidity model to the non-VA patient data. Although the non-VA sample size was smaller than the VA, preliminary analysis suggested no differences in risk-adjusted mortality between the non-VA and VA cohorts. CONCLUSIONS With some adjustments, the NSQIP methodology can be implemented and generates reasonable predictive models within non-VA hospitals.

Insulin inhibits secretin-induced pancreatic bicarbonate output via cholinergic mechanisms

INTRODUCTION

Exogenous insulin inhibits secretin-stimulated pancreatic bicarbonate output via a dose-dependent mechanism; this effect is prevented by pancreatic denervation.

AIMS

To investigate possible cholinergic mediation, we examined the effect of bethanechol on secretin-stimulated pancreatic secretion during euglycemic, hyperinsulinemic clamp.

METHODOLOGY

In four dogs with chronic pancreatic fistulas, euglycemic, hyperinsulinemic clamp (1.25 mU/kg/min) was begun after a 30-minute basal period; computer-assisted glucose administration maintained euglycemia. Control studies were performed with volume-matched and rate-matched vehicle infusion. After 1 hour, secretin infusion was begun at a dosage of 16 ng/kg/h; the dose was doubled every 30 minutes. The studies were then repeated during background bethanechol infusion (90 microg/kg/h) begun 30 minutes after clamp initiation. Pancreatic juice was analyzed for bicarbonate and protein; serum samples were analyzed for glucose and insulin.

RESULTS

Exocrine outputs and serum glucose and insulin levels did not differ in the basal period. Insulin levels were significantly elevated during the euglycemic, hyperinsulinemic clamp (62 microU/mL versus 12 microU/mL; p < 0.01); glucose levels did not differ. As before, secretin-induced bicarbonate output was inhibited by euglycemic, hyperinsulinemic clamp. The inhibitory effect of insulin was reversed by bethanechol. Despite the euglycemic, hyperinsulinemic clamp, secretin-induced bicarbonate output was potentiated by bethanechol at higher secretin doses (p < 0.05).

CONCLUSION

These data confirm that cholinergic mechanisms mediate insulin's inhibition of secretin-induced pancreatic bicarbonate output.

Captopril inhibits secretin-induced pancreatic bicarbonate output

BACKGROUND

Renin-angiotensin systems function at both the organ and systemic levels. Previous studies suggest that angiotensin II (Ang II) stimulates pancreatic secretion in vitro. In contrast, in vivo studies suggest that Ang II inhibits pancreatic secretion. To further assess Ang II's influence on pancreatic secretion, we examined the effect of captopril on secretin-stimulated pancreatic output.

METHODS

After a 30-min basal period, four conscious dogs with chronic gastric and Herrera pancreatic fistulas received an intravenous bolus of captopril (0.1 mg/kg) followed by a continuous infusion (25 microg/kg/min). Control studies were performed with volume- and rate-matched saline infusion. After 1 h, secretin infusion was begun at 16 ng/kg/h, doubling the dose every 30 min. Pancreatic juice was analyzed for bicarbonate and protein. A paired t test was used to assess statistical significance.

RESULTS

When compared to controls, pancreatic bicarbonate outputs were lower during captopril administration; the difference between captopril and control was statistically significant at the highest secretin dose. Protein outputs also appeared lower during captopril administration, although these differences were not statistically significant.

CONCLUSION

These data suggest that Ang II may augment secretin-induced pancreatic secretion. Further, the data seemingly refute the inhibitory role attributed to Ang II in earlier studies.

Recent experience with percutaneous endoscopic gastrostomy/jejunostomy (PEG/J) for enteral nutrition

BACKGROUND

Enteral feeding is the preferred means of nutritional support in patients unable to eat orally. Jejunal-placed feeding tubes are often considered optimal for this purpose. Successful administration of such tube feedings depends on the method of placement and the size of the tube. Herein we review our experience with endoscopically placed jejunal feeding tubes.

METHODS

Thirteen percutaneous endoscopic gastrostomy/jejunostomy (PEG/J) tubes were placed in 13 patients at the Emory University hospital by one surgeon. Indications for jejunal placement included aspiration in five patients and suspicion of increased reflux susceptibility in eight patients. Insertion of an 8.5-Fr nasobiliary tube was attempted in nine patients using the technique described by Coates and MacFadyen. A 12-Fr tube was placed in four patients using a technique that took advantage of previously placed PEG tubes.

RESULTS

Initial placement was successful in all but one patient. Nine tube-related complications occurred in seven patients. These included six tube occlusions, one tube site infection, one peristomal leak, and one tube perforation that required replacement. Five of six tube occlusions (83%) occurred in the smaller 8.5-Fr. tubes. There was one non-tube-related death.

CONCLUSIONS

PEG/J insertion can be performed successfully and safely in most patients. Long-term tube patency is, however, dependent on the use of tubes with a large diameter; thus, modalities that enable placement of larger-sized tubes are preferable. Further technical developments are needed to facilitate the endoscopic insertion of larger jejunostomy tubes.

Hyperglycemia alone does not inhibit secretin-induced pancreatic bicarbonate secretion

Administration of exogenous insulin (INS) inhibits secretin-stimulated pancreatic bicarbonate (HCO3) output via a dose-dependent, neurally mediated mechanism. To determine whether this effect was due to systemic hyperinsulinemia or to reduced endogenous insulin production, we examined the effect of hyperglycemia on secretin-stimulated pancreatic secretion. Chronic pancreatic fistulae were created in six dogs. After 30 minutes of equilibration, a computer-assisted hyperglycemic clamp protocol was used to maintain glucose (GLU) levels 100 or 150 mg/dL above basal in clamp animals; control animals received volume- and rate-matched infusions of 0.9% saline. One hour after beginning the clamp period, intravenous secretin dose-response (16-125 ng/kg/h) was begun, doubling the dose every half hour. Unstimulated (0-30 minutes) HCO3, GLU, and INS levels did not differ between groups. INS and GLU levels in clamp animals were significantly elevated during clamp (30-90 minutes) and stimulated (90-210 minutes) periods. For the same periods, HCO3 secretion was not significantly changed despite profound hyperinsulinemia. We conclude that systemic hyperinsulinemia alone does not inhibit secretin-stimulated HCO3 output. Since exogenous INS exerts feedback regulation on the pancreas, we propose that suppression of endogenous INS secretion mediates the previously reported inhibitory response.

Growth and function of isolated canine pancreatic ductal cells

These studies investigated the growth characteristics and functional properties of isolated canine pancreatic ductal epithelial cells. Cells were isolated from the accessory pancreatic duct and cultured by using three conditions: on vitrogen-coated petri dishes with fibroblast conditioned medium (nonpolarized); in vitrogen-coated Transwells above a fibroblast feeder layer (polarized); or as organotypic rafts above a fibroblast-embedded collagen layer (polarized). Growth characteristics, transepithelial resistances, and carbonic anhydrase and cyclic adenosine monophosphate (AMP) responses were evaluated. Under polarized conditions, the cells grew as monolayers with columnar epithelial characteristics. The monolayers developed high transepithelial resistance and became impervious to the passage of horseradish peroxidase. Epithelial growth factor (EGF) (2 ng/ml) stimulated ductal cell growth and accelerated the formation of a high-resistance monolayer. Forskolin (10 microM) rapidly decreased transepithelial resistance. Carbonic anhydrase activity, which was lower in nonpolarized compared with polarized conditions, was stimulated by carbachol (175 microM). Secretin, however, did not stimulate carbonic anhydrase activity in these cells. Although secretin stimulated adenylyl cyclase activity in early-passage cells, this response was lost in later-passage cells. Both vasoactive intestinal polypeptide (VIP; 1 microM) and forskolin (10 microM) consistently increased adenylyl cyclase activity. Isolated canine pancreatic ductal epithelial cells proliferate in vitro, develop high-resistance epithelial monolayers, and respond to stimuli that activate adenylyl cyclase. These cells should provide a useful model for regulatory studies of ductal cell functions.

Experience with percutaneous transhepatic cholangioscopy (PTCS) in the management of biliary tract disease

BACKGROUND

Biliary tract disorders often present significant management difficulties, particularly in patients who are poor surgical candidates. Percutaneous transhepatic cholangioscopy (PTCS) is an infrequently utilized alternative that might offer significant therapeutic benefit. We reviewed our experience with the use of this modality as a definitive therapy for biliary tract disorders.

METHODS

Patient records at the Atlanta VAMC and Emory University hospitals were reviewed. We identified 17 patients who had undergone 25 PTCS interventions between August 1994 and December 1998. The indications for PTCS included dilatation of biliary-enteric anastomoses in four patients, biliary stone removal (with or without lithotripsy) in eight patients, stricturoplasty in four patients, biopsy of suspected biliary neoplasms in seven patients, and removal of obstructing clot in one patient. Most procedures (n = 17) were performed through percutaneous transhepatic tracts (12-18 Fr) that were <1 week old. All tracts were dilated to operating size on the day of the procedure. All patients received periprocedural antibiotics.

RESULTS

The interventions were successful in seven of eight stone removals, four of five stricturoplasties, three of four anastomotic dilatations, seven of seven biopsies, and the single clot removal. The only complication involved one episode of hemobilia, requiring angio-embolization of a small branch of the right hepatic artery.

CONCLUSIONS

PTCS is a safe, useful, and well-tolerated adjunct to the more common endoscopic and surgical techniques for managing complicated biliary tract disorders. Our experience suggests that PTCS can be performed early, without prolonged sequential dilatation of the percutaneous transhepatic tract, and may allow avoidance of operation in high-risk surgical candidates.

Current management of endoscopic feeding tube dysfunction

Surgically placed gastrostomy and jejunostomy feeding tubes allow administration of enteral nutrition for patients who are unable to swallow safely. Several endoscopic techniques have been used for tube placement. Endoscopically placed feeding tubes provide access to the gastrointestinal tract, but only when patent. Use of the approaches presented permits optimal feeding tube care and prolongs tube patency. Table 1 summarizes the recommendations for preventing and restoring patency to feeding tubes.

Alternative methods for management of the complicated gallbladder

Laparoscopic cholecystectomy is the procedure of choice for symptomatic cholelithiasis. However, in the presence of acute cholecystitis, 10% to 15% of patients face conversion to laparotomy. Alternatives to conventional therapy may therefore help to improve the clinical outcome of patients with complicated gallbladder disease. In selecting patients for alternative therapies, preoperative and intraoperative factors must be considered. Preoperative factors include the severity of biliary disease and preexisting medical risk factors; whereas intraoperative factors include conditions at the time of surgery that make dissection difficult or unsafe. Alternative therapies provide the least invasive management to safely temporize or definitively treat the acute condition. These alternatives include percutaneous cholecystostomy alone or followed by laparoscopic cholecystectomy, laparoscopic cholecystostomy followed by laparoscopic cholecystectomy, laparoscopic subtotal cholecystectomy, endoscopic retrograde cannulation of the gallbladder, and extracorporeal shockwave lithotripsy. By appropriate selection of the initial therapeutic approach, the surgeon may ultimately improve the clinical outcome in these complicated patients.

Management of pancreatic pseudocysts

BACKGROUND

Operative internal drainage has been standard treatment for chronic unresolved pancreatic pseudocysts (PPs). Recently, percutaneous external drainage (PED) has become the primary mode of treatment at many medical centers.

STUDY DESIGN

A retrospective chart review was performed of 96 patients with PPs who were managed between 1987 and 1996. Longterm followup information was obtained by telephone and mail questionnaire.

RESULTS

Twenty-seven patients underwent computed tomographic (CT)-guided PED. PP resolution occurred in 17 patients. Clinical deterioration or secondary infection mandated urgent pancreatic debridement in 7 (26%) patients and cystgastrostomy in 2 (7%) patients. There was one hospital death in this group. Thirty-two patients underwent cystgastrostomy or cystjejunostomy (n = 21), distal pancreatectomy (n = 8), pancreatic debridement and external drainage (n = 2), or cystectomy (n = 1). Two (6%) patients required postoperative pancreatic debridement for failure of resolution and peritonitis and two patients underwent PED of abscess. There was one hospital death in the expectantly managed group of 37 patients. Median followup of 3 years (range, 0.5-9.3 years) in 66 patients revealed that 6, 3, and 4 patients of PED, surgery, and expectantly managed groups, respectively, had radiologic evidence of recurrent PPs.

CONCLUSIONS

Operative management for PPs appears to be superior to CT-guided PED. Although the later was often successful, it required major salvage procedures in one third of the patients. An expectant management protocol may be suitable for selected patients.

Exogenous insulin does not influence CCK- and meal-stimulated pancreatic secretion

Although previous reports suggest interactions between the endocrine and the exocrine pancreas, insulin's effect on pancreatic exocrine function remains unclear. Chronic pancreatic fistulae were created in five dogs; these animals were studied using the euglycemic, hyperinsulinemic clamp technique. After a 30-min unstimulated period, both groups received a 60-min, 1.5 mU/kg/min insulin (clamp) or vehicle (control) infusion. Cholecystokinin (CCK) or meal stimulation was then begun. Intravenous CCK was initiated at 12.5 ng/kg/h; the CCK dose was doubled every 30 min until 100 ng/kg/h was achieved. The intraduodenal liquid test meal (1.5 kcal/ml; 15% protein, 32% fat, 53% carbohydrate) was administered at 100 ml/h. Unstimulated (0- to 30-min) serum glucose and insulin levels and pancreatic bicarbonate and protein outputs did not differ between groups. Clamp (30- to 90-min) and stimulated (90- to 210-min) insulins were significantly elevated in clamp groups (p < 0.001); glucose and bicarbonate were unchanged. Exocrine outputs during clamp periods were unaffected by insulin. Neither CCK- nor meal-stimulated pancreatic secretion (90-210 min) was influenced by insulin administration. These data suggest that hyperinsulinemia does not alter pancreatic acinar cell secretion in the intact animal.

The effect of pancreatic denervation and atropine on the cholecystokinin-induced pancreatic exocrine response

To study the influence of extrapancreatic neural and cholinergic activity on the pancreatic response to cholecystokinin (CCK), six dogs underwent creation of Herrera pancreatic fistulas, placement of Thomas gastric cannulas, and distal pancreatectomies (innervated; INN). Six additional dogs were prepared similarly, with the addition of total extrinsic pancreatic denervation (denervated; DEN). The pancreatic protein and bicarbonate response to graded 12.5 to 200 ng/kg/h CCK doses was determined for INN and DEN animals both alone and with 10 micrograms/kg/h atropine infusion. The influence of extra-pancreatic neural and cholinergic activity on secretin's potentiation of the CCK-induced pancreatic response was then determined by repeating the studies with a 125 ng/kg/h secretin infusion. The latter results were compared to those predicted by summating the responses seen during separate 12.5-200 ng/kg/h CCK dose-response and 125 ng/kg/h secretin studies. Unstimulated protein output was diminished by atropine in INN animals (78 +/- 21 vs. 39 +/- 9 mg/15 min; p < 0.05) but not in DEN animals. Unstimulated bicarbonate outputs, integrated bicarbonate and protein outputs, and bicarbonate and protein dose-response curves were unaffected by denervation or atropine. Potentiation of CCK-induced bicarbonate output by secretin was also unaffected by atropine and denervation. We conclude that cholinergic elements are involved in unstimulated, but not CCK-induced, enzyme secretion. Further, potentiation of CCK-induced bicarbonate output by secretin does not depend on extrinsic neural or cholinergic elements.

Insulin inhibits secretin-stimulated pancreatic bicarbonate output by a dose-dependent neurally mediated mechanism

Although previous reports suggest interactions between endocrine and exocrine pancreas, insulin's effect on pancreatic exocrine function remains unclear. Chronic pancreatic fistulas were created in six dogs with innervated INN and five dogs with denervated (DEN) pancreata; these animals were studied using the euglycemic, hyperinsulinemic clamp technique. After a 30-min unstimulated period, both groups received a 60-min 1.5 mU.kg-1.min-1 insulin (clamp) or vehicle (control) infusion. Intravenous secretin was then initiated at 16 ng.kg-1.h-1; the secretin dose was doubled every 30 min until 125 ng.kg-1.h-1 was achieved. These studies were then repeated in INN animals during infusion of a 10 micrograms.kg-1.h-1 atropine background. Finally, INN animals underwent a similar unstimulated period followed by a 1.25 mU.kg-1.min-1 insulin (clamp) or vehicle (control) infusion. after 60 min, a 64 ng.kg-1.h-1 secretin infusion was initiated. Insulin infusion was then increased by 0.25 mU.kg-1.min-1 at 30-min intervals until 2.0 mU.kg-1.min-1 was reached. Unstimulated (0-30 min) serum glucose and insulin levels and pancreatic bicarbonate and protein outputs did not differ between groups. Clamp (30-90 min) and stimulated (90-210 min) insulin were each significantly elevate in clamp groups (81.9 +/- 2.4 vs. 7.0 +/- 0.3 microU/ml, P < 0.001); glucose and bicarbonate were unchanged. Protein outputs during clamp (64 +/- 9 vs. 24 +/- 6 mg/10 min; P < 0.05) and secretin-stimulated (52 +/- 9 vs. 29 +/- 3 mg/10 min; P < 0.05) periods were diminished by atropine but were unaffected by insulin. Secretin-stimulated (90-210 min) bicarbonate output was diminished by insulin (0.03 +/- 0.01 vs. 0.31 +/- 0.05 meq/10 min; P < 0.003) in INN but not DEN animals; this effect was partially reversed by atropine. Dose-response studies demonstrated a threshold for insulin's inhibitory actions between 1.5 and 1.75 mU.kg-1.min-1. These data provide further evidence for exocrine-endocrine regulatory interactions and suggest that insulin may influence secretin's stimulation of ductal cell secretion by a mechanism that is at least partially cholinergic in character.

Somatostatin inhibits cholecystokinin-induced pancreatic protein secretion via cholinergic pathways

Although somatostatin is a potent inhibitor of pancreatic exocrine secretion in vivo, its mechanism of action remains unclear. The influence of extrapancreatic nerves and intrapancreatic cholinergic activity on somatostatin-induced inhibition of pancreatic exocrine secretion was studied in conscious dogs. Chronic pancreatic fistulae were created in six mongrel dogs, and a second group of six dogs also underwent complete pancreatic denervation. The pancreatic responses to graded doses of cholecystokinin (12.5-200 ng/kg/h) and bethanechol (57-916 micrograms/kg/h), both alone and during background infusion of somatostatin-14 (800 pm/kg/h), were determined in all dogs. The cholecystokinin dose-response with a somatostatin-14 background was then repeated with the addition of atropine (10 micrograms/kg/h). In both groups of animals, cholecystokinin elicited a dose-dependent increase in pancreatic protein secretion that was inhibited significantly by somatostatin-14. Regardless of the status of extrapancreatic nerves, atropine further inhibited cholecystokinin-induced protein secretion beyond that evoked by somatostatin-14. In both innervated and denervated animals, cholinergic stimulation with bethanechol elicited a dose-dependent increase in pancreatic protein secretion that was unaffected by somatostatin-14. We conclude that extrapancreatic nerves do not mediate the inhibitory effects of somatostatin-14. Somatostatin-14 appears to inhibit cholecystokinin-induced pancreatic secretion by an intrapancreatic cholinergic mechanism.

Adrenergic pathways do not mediate peptide YY-induced inhibition of pancreatic exocrine secretion

The influence of extrapancreatic nerves and intrapancreatic adrenergic activity on the inhibition of pancreatic exocrine secretion by peptide YY (PYY) was studied in conscious dogs. Chronic pancreatic fistulae were created in five mongrel dogs while a second group of five dogs also underwent complete pancreatic denervation. After recovery, a continuous infusion of secretin (62 ng/kg/h) and cholecystokinin (CCK; 50 ng/kg/h) was administered over 2 h. An infusion of PYY (400 pmol/kg/h) was then given randomly, during either the first or second experimental hour. The experiments were then replicated after establishing adrenergic blockade with continuous background infusions of either phentolamine (0.2 mg/kg/h), propranolol (0.5 mg/kg bolus) or a combination of phentolamine and propranolol. The secretin/cholecystokinin-induced bicarbonate and protein outputs were significantly inhibited by PYY in both the innervated and denervated animals. Adrenergic blockade failed to eliminate the inhibitory effects of PYY. We conclude that extrapancreatic neural pathways, including adrenergic mechanisms, do not mediate the inhibitory effects of PYY. The results suggest that PYY inhibits secretin/cholecystokinin-induced pancreatic response by an indirect nonadrenergic mechanism.

Metastatic implantation of an oral squamous-cell carcinoma at a percutaneous endoscopic gastrostomy site

Percutaneous endoscopic gastrostomy (PEG) has become an important adjunct in the care of the head-and-neck cancer patient. When resection will likely affect swallowing, PEG can be performed just prior to cancer resection. However, it is unclear whether PEG should be the procedure of choice for establishing enteral access in head-and-neck cancer patients. In this report we describe a man with advanced oral squamous cell carcinoma who had a One-Step PEG button inserted immediately prior to his cancer resection. Six months later, the patient developed metastatic squamous-cell carcinoma at the PEG site. Although the mechanism of spread cannot be confirmed, direct seeding from passage through the cancer-filled oral cavity seems likely. Methods of establishing enteral access which avoid tumor-contaminated fields, such as use of an overtube during conventional PEG, open gastrostomy, or laparoscopic gastrostomy, may be more appropriate in head-and-neck cancer patients.

Candida in pancreatic infection: a clinical experience

Pancreatic infection remains a significant clinical problem, with substantial morbidity and mortality. Published case reports of Candida species identified in these infections prompted a review of 17 consecutive patients recently treated for peripancreatic infection by scheduled relaparotomy. Six patients were transferred from other hospitals, all having undergone prior operative intervention (median stay elsewhere: 58 days). The 11 other patients underwent initial operation an average of 14 days after admission. Candida species were identified in the initial operative cultures of 5 patients (29%), three of whom had undergone previous drainage at other hospitals. Two patients (11.7%) had Candida identified at subsequent operation. Six patients were treated with Amphotericin B for a median of 12 days (range 6-32) and a median dosage of 420 mg (range 225-830 mg). All patients were cleared of their Candida infection, but three subsequently died, for an overall mortality of 17.6%. Candida infected patients suffered a 42 per cent mortality. Our series supports the suspicion that Candida is much more frequent (41% of patients) than previously recognized in peripancreatic sepsis, and is commonly acquired after the initial operation. Amphotericin B therapy is effective in clearing Candida infection, but affected patients have a high associated mortality.

Pancreatic denervation does not influence glucose-induced insulin response

BACKGROUND

Pancreatic transplantation results in denervation and loss of splanchnic venous drainage and inflicts numerous metabolic abnormalities. However, it is unclear whether denervation or loss of splanchnic venous drainage is responsible for the observed metabolic abnormalities.

METHODS

To discern denervation's role in these abnormalities, four mongrel dogs underwent extrinsic pancreatic denervation with preservation of splanchnic venous drainage. These animals, as well as four innervated control subjects, underwent standardized enteral and intravenous glucose tolerance testing. In addition, hyperglycemic clamps that maintained stable serum glucose elevations at either 2.8 or 8.3 mmol/L above basal were also performed.

RESULTS

Prestimulated glucose (90.4 +/- 2.7 vs 92.6 +/- 4.9 mg/dl) and insulin levels (6.8 +/- 1.7 vs 8.5 +/- 1.4 muU/ml) did not differ between innervated and denervated groups. Integrated incremental enteral glucose (5320 +/- 1900 vs 7790 +/- 2000 mg/dl) and insulin (2565 +/- 350 vs 2836 +/- 598 muU/ml) levels did not differ between groups. Integrated incremental intravenous glucose (3680 +/- 400 vs 3950 +/- 1000 mg/dl) and insulin (741 +/- 70 vs 1053 +/- 326 muU/ml) levels also did not differ. During glucose clamp studies, time-weighted 60 to 120-minute insulin levels (2.8 mmol/L, 30 +/- 5.0 vs 24 +/- 4.8 muU/ml; 8.3 mmol/L, 57 +/- 5.9 vs 50 +/- 9.8 muU/ml) did not differ between groups. In addition, glucose disposal, cyclic insulin release, and insulin sensitivity indexes were unchanged by denervation.

CONCLUSIONS

Extrinsic pancreatic neural elements are not necessary for cyclic insulin release in response to enteral or parenteral glucose challenge or physiologic and pharmacologic hyperglycemia. These findings suggest that the previously described posttransplantation glucose and insulin abnormalities are not attributable to denervation.

Inhibition of pancreatic exocrine secretion by galanin

The influence of extrapancreatic nerves on the inhibition of meal- and secretogogue-induced pancreatic secretion by galanin was studied in conscious dogs. Chronic pancreatic fistulae were created in five mongrel dogs and a second group of five dogs also underwent complete pancreatic denervation. After recovery, galanin dose response (150-1,200 pmol/kg/h) revealed that 600 pmol/kg/h was the lowest dose of galanin to significantly inhibit pancreatic exocrine secretion. Pancreatic responses to a mixed meal, cholecystokinin (CCK) dose response (12.5-200 ng/kg/h), and secretin dose response (16-500 ng/kg/h) were determined. The experiments were then replicated with a continuous background infusion of galanin (600 pmol/kg/h). Galanin inhibited meal-, CCK-, and secretin-induced bicarbonate outputs in both the innervated and denervated pancreas. Galanin also inhibited meal- and CCK-induced protein responses in both groups. We conclude that extrapancreatic nerves do not mediate the inhibitory effects of galanin.

Extrapancreatic cholinergic nerves mediate cholecystokinin-stimulated pancreatic polypeptide release

Although vagal cholinergic stimulation is the predominant regulatory mechanism governing the release of pancreatic polypeptide (PP), recent studies suggest that cholecystokinin (CCK) is also an important mediator. The present study examined the role of cholinergic neural pathways in the PP response to exogenous CCK-8 using a selectively denervated canine pancreas model. Chronic denervated pancreatic preparations were created in five dogs, while five dogs underwent sham laparotomy as controls. On study days, the fasted animals were infused intravenous CCK-8 (40 or 400 pmole/kg/hr) for 60 min both with and without atropine (20 micrograms/kg/hr). Plasma was collected at 20-min intervals and PP levels were determined by radioimmunoassay. CCK-8 elicited a dose-dependent increase in circulating PP in dogs with a neurally intact pancreas. Atropine and pancreatic denervation eliminated the PP response to CCK-8 at 40 pmole/kg/hr (P < 0.01) and inhibited the PP response to CCK-8 at 400 pmole/kg/hr (P < 0.05). The high dose of CCK-8 still elicited a small PP response in the denervated dogs (P < 0.05), which was subsequently abolished by the addition of atropine. These findings suggest that extrapancreatic cholinergic nerves are essential components of CCK-stimulated PP release, and that intrapancreatic cholinergic activity may play a limited role.

Potentiation of canine pancreatic bicarbonate output by oleic acid is not neurally dependent

To study neural involvement in potentiation of acid-induced pancreatic bicarbonate output, six dogs underwent extrapancreatic denervation and pancreatic fistula creation. Pancreatic responses to secretin (16 and 32 ng/kg/h) and cholecystokinin (50 ng/kg/h) were then assessed. The duodenum was then perfused with three sets of perfusates. The first set contained hydrochloric acid with either D- or L-phenylalanine. The second set contained bovine serum albumin and hydrochloric acid with or without oleic acid; the albumin and acid were varied so that each 50 ml contained 1, 2, or 4 meq titratable acid (pH 2.0-4.5). The third set was identical to the second except for initial pH of 3.5. Pancreatic responses predicted upon addition of cholecystokinin to secretin, L-phenylalanine to hydrochloric acid, or oleic acid to bovine serum albumin were compared with observed responses. At both doses, secretin-induced bicarbonate output was increased by cholecystokinin (16 ng/kg/h: 0.88 +/- 0.29 meq/15 min; 32 ng/kg/h: 1.01 +/- 0.23 meq/15 min). The latter significantly exceeded predicted output (16 ng/kg/h: 0.38 +/- 0.10 meq/15 min; 32 ng/kg/h: 0.58 +/- 0.15 meq/15 min), verifying potentiation. L-phenylalanine failed to potentiate bicarbonate output evoked by acidified D-phenylalanine. In contrast, addition of oleic acid to pH 2.0 or 3.5 bovine serum albumin potentiated bicarbonate output. These data suggest that enteropancreatic reflexes mediate potentiation of acid-induced pancreatic bicarbonate output by amino acids, but not by fatty acids.

Thermal injury of the posterior duodenum during laparoscopic cholecystectomy

While complications of laparoscopic cholecystectomy occur in 3-7% of cases, bowel injuries are uncommonly reported. Bowel injuries appear to be of two types: penetrating bowel injury from either the Veress needle or trocar, and thermal bowel injury from either contact or conductive burn. The duodenum is usually spared from Veress needle or trocar injury because of its posterior location. However, during dissection in the triangle of Calot, the duodenum is at risk for direct contact burn or energy conduction burn. In this report we describe a presumed conductive burn injury of the posterior second portion of the duodenum which followed laparoscopic cholecystectomy. This unrecognized injury resulted in full-thickness necrosis of the duodenal wall with delayed perforation. This injury was successfully managed with pyloric exclusion. The diagnosis and management of this previously unreported injury are described.

Effect of pancreatic denervation and atropine on the pancreatic response to secretin

To study the influence of extrapancreatic nerves and intrapancreatic cholinergic activity on the pancreatic response to secretin, six dogs underwent extrapancreatic denervation and creation of pancreatic fistulae. A second group of six dogs had pancreatic fistulae created without pancreatic denervation. The pancreatic exocrine response to graded doses of secretin (16-500 ng/kg/h) was determined, both alone and during a background infusion of cholecystokinin-octapeptide (CCK8, 50 ng/kg/h). All studies were replicated during administration of atropine (10 micrograms/kg/h). Secretin-induced bicarbonate output was significantly inhibited by atropine in both the innervated and denervated groups. Combined secretin and CCK8 elicited a dose-dependent increase in bicarbonate output and a sustained increase in protein output in both groups, regardless of atropine. In addition, potentiation of secretin-induced bicarbonate output by CCK8 was observed despite both extrinsic pancreatic denervation and administration of atropine. We conclude that endogenous intrapancreatic cholinergic activity influences the pancreatic response to secretin. Potentiation of secretin-induced bicarbonate output by CCK, however, is not dependent on neural mediation.