Incidence of Complicated Appendicitis as a Metric of Health Care Delivery

BACKGROUND

Complicated acute appendicitis (CAA) has been linked to extremes of age, racial and socioeconomic disparities, public insurance, and remote residency. CAA rate has been used from 2005 to 2018 as a health care quality metric, with the assumption that delay in treatment was a main cause of perforation. We studied factors that could contribute to CAA focusing on modifiable factors which could be altered as part of a health care delivery system.

MATERIALS AND METHODS

All primary admissions for acute appendicitis (AA) from the 2010 Nationwide Inpatient Sample were linked to 2010 state-level physician density data. CAA was distinguished by codes for perforation, generalized peritonitis, or intra-abdominal abscess. A multivariable logistic regression model for CAA prediction was built.

RESULTS

A total of 288 556 patients were admitted with AA and 86 272 (29.9%) had CAA. Independent factors, linked to CAA, included age outside the 10-39 range (odds ratio (OR) = 2.1-2.4 and all P < .001), male gender (OR = 1.2), malnutrition (OR = 6.2), diabetes mellitus (OR = 2.1), chronic anemias (OR = 1.9), nonprivate insurances (OR 1.2-1.5), nonmetropolitan patient's residence (OR = 1.15), and Midwest region (OR = 1.2). Patient income and physician coverage were not significant factors after adjustment for all other covariates. Highest CAA fraction of 39.6% was noted in rural patients admitted to urban teaching facilities.

DISCUSSION

Although provider coverage at the state level may seem adequate and not related to increased CAA rates, the distance patients traveled for their definitive surgical care correlated with higher rates of CAA. Adjusting physician distribution into nonurban settings closer to patients could decrease rates of CAA by diminishing time to definitive care.

Wellbeing as Defined by Resident Physicians: A Qualitative Study

The importance of resident wellbeing is increasingly recognized by the ACGME as essential. While prior studies have quantified wellbeing/burnout, few have defined wellbeing from the resident-physician perspective. A REDCap® survey was distributed to residents in various programs, responses were grouped by theme, and data analyzed via chi-square. From 19 institutions, 53/670 responded, from university (34.0%), community (30.2%), and community/university-affiliated (30.2%) programs, mostly surgical (84.9%), followed by medical (9.4%). Wellbeing was defined by mental and spiritual/religious health (33.8%), overall health (23.0%), free time/time management (23.0%), and job/salary satisfaction (18.9%). Proposed changes to traditional training included fewer hours and more schedule flexibility (38.2%), and increased/improved support/feedback (14.7%). Nearly half of the respondents perceived lacking education on career longevity. Wellbeing is paramount to the personal/professional development of residents. Data on resident-defined wellbeing are lacking. The improved understanding of wellbeing defined here can be used to improve residency training programs.

Use of CT Scans for Abdominal Pain in the ED: Factors in Choice

Overutilization of healthcare resources is a threat to long-term healthcare sustainability and patient outcomes. CTis a costly but efficient means of assessing abdominal pain; however, 97 per cent of ED physicians acknowledge its overutilization. This study sought to understand factors that influence ED providers’ decision regarding CT use in the evaluation of abdominal pain. After evaluating a patient for acute abdominal pain, ED providers filled in a form in which the primary diagnosis and index of suspicion were recorded. Bivariate and multivariate analyses were used to identify predictors of outcomes. The CT scan utilization rate was 54.82 per cent. Whereas 34.11 per cent of CT scans were normal, 30 per cent yielded an acute abdominal pathology. Tenderness and rebound tenderness were positive predictors of high index of suspicion [odds ratio (OR) 2.09 and 2.54, respectively]. These variables were also predictive of obtaining a CT scan [OR 2.64 and 3.41, respectively]. Compared with whites, the index of suspicion was 26 per cent and 56 per cent less likely to be high when patients were black [OR 0.73] or Hispanic [OR 0.44] respectively. Blacks and Hispanics were less likely to have CT scans performed than whites [OR 0.58 and 0.48, respectively]. Leukocytosis significantly affected the index of suspicion for acute abdominal pathology, obtaining a CTscan and the acuity of CTscan diagnosis on multivariate analysis. Patients aged ≥60 years had 2.03 odds of acute CT finding compared with those aged <60 years. There is a need for committed efforts to optimize CT scan utilization and eliminate socioeconomic disparities in health care.

Measured versus Estimated Blood Loss: Interim Analysis of a Prospective Quality Improvement Study

Estimated blood loss (EBL) is an increasingly important factor used to predict outcomes, such as morbidity and mortality, length of stay, and readmissions, after major abdominal operations. However, blood loss is difficult to estimate, with frequent under- and overestimations, consequences of which can be potentially dangerous for individual patients and confounding for scoring systems relying on EBL. We hypothesized that EBL is often inaccurate and have pro-spectively enrolled consecutive patients undergoing major elective intra-abdominal operations. Actual hemoglobin levels were measured and used to calculate the measured blood loss (MBL), which was compared with the EBL, as estimated both by surgeons (sEBL) and anesthesiologists (aEBL). Of 23 eligible cases at interim analysis, pancreaticoduodenectomy (n = 8) was the most common, followed by colectomy (n = 3), hepatectomy (n = 3) and gastrectomy (n = 2), biliary excision and reconstruction (n = 2), combined gastrectomy + colectomy (n = 1), radical nephrectomy (n = 1), open cholecystectomy (n = 1), pancreatic debridement (n = 1), and exploratory laparotomy (n = 1). aEBL overestimated MBL by 192 mL (143%) on average. The aEBL was significantly greater than the MBL ( P = 0.004), whereas the sEBL was significantly less than the MBL ( P = 0.009). In conclusion, surgeons significantly underestimate and anesthesiologists significantly overestimate EBL. This finding impacts not only immediate patient care but also the interpretation of scoring systems relying on EBL.

Use of CT Scans for Abdominal Pain in the ED: Factors in Choice

Overutilization of healthcare resources is a threat to long-term healthcare sustainability and patient outcomes. CT is a costly but efficient means of assessing abdominal pain; however, 97 per cent of ED physicians acknowledge its overutilization. This study sought to understand factors that influence ED providers' decision regarding CT use in the evaluation of abdominal pain. After evaluating a patient for acute abdominal pain, ED providers filled in a form in which the primary diagnosis and index of suspicion were recorded. Bivariate and multivariate analyses were used to identify predictors of outcomes. The CT scan utilization rate was 54.82 per cent. Whereas 34.11 per cent of CT scans were normal, 30 per cent yielded an acute abdominal pathology. Tenderness and rebound tenderness were positive predictors of high index of suspicion [odds ratio (OR) 2.09 and 2.54, respectively]. These variables were also predictive of obtaining a CT scan [OR 2.64 and 3.41, respectively]. Compared with whites, the index of suspicion was 26 per cent and 56 per cent less likely to be high when patients were black [OR 0.73] or Hispanic [OR 0.44] respectively. Blacks and Hispanics were less likely to have CT scans performed than whites [OR 0.58 and 0.48, respectively]. Leukocytosis significantly affected the index of suspicion for acute abdominal pathology, obtaining a CT scan and the acuity of CT scan diagnosis on multivariate analysis. Patients aged ≥60 years had 2.03 odds of acute CT finding compared with those aged <60 years. There is a need for committed efforts to optimize CT scan utilization and eliminate socioeconomic disparities in health care.

Measured versus Estimated Blood Loss: Interim Analysis of a Prospective Quality Improvement Study

Estimated blood loss (EBL) is an increasingly important factor used to predict outcomes, such as morbidity and mortality, length of stay, and readmissions, after major abdominal operations. However, blood loss is difficult to estimate, with frequent under- and overestimations, consequences of which can be potentially dangerous for individual patients and confounding for scoring systems relying on EBL. We hypothesized that EBL is often inaccurate and have prospectively enrolled consecutive patients undergoing major elective intra-abdominal operations. Actual hemoglobin levels were measured and used to calculate the measured blood loss (MBL), which was compared with the EBL, as estimated both by surgeons (sEBL) and anesthesiologists (aEBL). Of 23 eligible cases at interim analysis, pancreaticoduodenectomy (n = 8) was the most common, followed by colectomy (n = 3), hepatectomy (n = 3) and gastrectomy (n = 2), biliary excision and reconstruction (n = 2), combined gastrectomy + colectomy (n = 1), radical nephrectomy (n = 1), open cholecystectomy (n = 1), pancreatic debridement (n = 1), and exploratory laparotomy (n = 1). aEBL overestimated MBL by 192 mL (143%) on average. The aEBL was significantly greater than the MBL (P = 0.004), whereas the sEBL was significantly less than the MBL (P = 0.009). In conclusion, surgeons significantly underestimate and anesthesiologists significantly overestimate EBL. This finding impacts not only immediate patient care but also the interpretation of scoring systems relying on EBL.

Detecting accidental punctures and lacerations during cholecystectomy in large datasets: Two methods of analysis

BACKGROUND

After the Institute of Medicine (IOM) report To Err Is Human highlighted the impact of medical errors, the Agency for Healthcare Research and Quality (AHRQ) developed Patient-Safety Indicators (PSI) to improve quality by identifying potential inpatient safety problems. PSI-15 was created to study accidental punctures and lacerations (APL), but PSI-15 may underestimate APLs in populations of patients. This study compares PSI-15 with a more inclusive approach using a novel composite of secondary diagnostic and procedural codes.

METHODS

We used Nationwide Inpatient Sample (NIS) data (2000-2012) from AHRQ's Healthcare Cost and Utilization Project (H-CUP). We analyzed PSI-15-positive and -negative cholecystectomies. Cross tabulations identified codes that were significantly more frequent among PSI-15-positive cases; these secondary diagnostic and procedural codes were selected as candidate members of a composite marker (CM) of APL. We chose cholecystectomy patients for study because this is one of the most common general operations, and the large size of NIS allows for meaningful analysis of infrequent occurrences such as APL rates.

RESULTS

CM identified 1.13 times more APLs than did PSI-15. Patients with CM-detected APLs were significantly older and had worse mortality, comorbidities, lengths of stay, and charges than those detected with PSI-15. Further comparison of these two approaches revealed that time-series analysis for both APL markers revealed parallel trends, with inflections in 2007, and lowest APL rates in July.

CONCLUSIONS

Although CM may yield more false positives, it appears more inclusive, identifying more clinically significant APLs, than PSI-15. Both measures presented similar trends over time, arguing against inflation in PSI-15 reporting. While arguably less specific, CM may increase sensitivity for detecting APL events during cholecystectomies. These results may inform the interpretation of other large population studies of APLs following abdominal operations.

Effectiveness of an Early Ultrasound Training Curriculum for General Surgery Residents

Ultrasound (US) is fast becoming an extension of the physical examination in most surgical settings. Unfortunately, few residency programs offer a formal US training curriculum to their general surgical residents. This study aimed to assess the efficacy of a formal US training module for general surgery residents. We studied the degree of improvement observed between junior and senior residents. A training-based study was conducted to evaluate baseline knowledge and skills. Subsequently, a formal didactic and practical training program for our surgery residents was instituted. Residents were then scored in various categories. A total of 18 surgical residents comprising 10 junior and 8 senior residents completed our US training module. There was no significant improvement in the scores of the senior resident group. In the junior group, the written test, image detection, optimization, and interpretation categories improved significantly after completion of the training module. Comparison of improvement in scores between junior and senior residents revealed a significantly better improvement in the junior group than in the senior group. Early training of surgical residents can significantly improve US performance in junior residents. This early training has the benefit of increased utilization of bedside US for diagnostic and procedural purposes. Interestingly, even without formal training, skill acquisition of senior residents is noted to occur during modern surgical training.

Clues to predict incidental gallbladder cancer

BACKGROUND

Consequences of incidental gallbladder cancer (iGBC) following cholecystectomy may include repeat operation (depending on T stage) and worse survival (if bile spillage occurred), both avoidable if iGBC were suspected preoperatively.

METHODS

A retrospective single-institution review was done. Ultrasound images for cases and controls were blindly reviewed by a radiologist. Chi-square and Student's t tests, as well as logistic regression and Kaplan-Meier analyses were used. A P ≤ 0.01 was considered significant.

RESULTS

Among 5796 cholecystectomies performed 2000-2013, 26 (0.45%) were iGBC cases. These patients were older (75.61 versus 52.27 years), had more laparoscopic-to-open conversions (23.1% versus 3.9%), underwent more imaging tests, had larger common bile duct diameter (7.13 versus 5.04 mm) and higher alkaline phosphatase. Ultrasound imaging showed that gallbladder wall thickening (GBWT) without pericholecystic fluid (PCCF), but not focal-versus-diffuse GBWT, was associated significantly with iGBC (73.9% versus 47.4%). On multivariable logistic regression analysis, GBWT without PCCF, and age were the strongest predictors of iGBC. The consequences iGBC depended significantly on intraoperative bile spillage, with nearly all such patients developing carcinomatosis and significantly worse survival.

CONCLUSIONS

Besides age, GBWT, dilated common bile duct, and elevated alkaline phosphatase, number of preoperative imaging modalities and the presence of GBWT without PCCF are useful predictors of iGBC. Bile spillage causes poor survival in patients with iGBC.

Effect of Residents on Operative Time and Complications: Focus on Laparoscopic Cholecystectomy in the Community

OBJECTIVE

To better understand important aspects of resident education in the perioperative setting, given that there are conflicting data regarding resident training and outcomes (e.g., operative times and complications). To study continuity of care in a resident-run outpatient hospital clinic.

DESIGN

Retrospective analysis of 2 databases.

SETTING

The study was set up in a community teaching hospital.

RESULTS

Of 4603 cases in a cholecystectomy database, 3302 (72%) were assisted by residents, with operative times ranging from 19 to 383 minutes, and 1576 (22.9%) were assisted by nonresidents. The average times were 93 and 77 minutes for resident- and non-resident-assisted cases, respectively. Complications were almost 3 times more likely for urgent vs. elective but were similar for resident-assisted vs. non-resident-assisted cases. The operative time was similar across PGY levels. Of 149 cases in a resident-run outpatient clinic, 100 (67%) of the residents participated in preoperative, intraoperative, and postoperative phases of case, but in only 4% of cases was it the same resident.

CONCLUSION

Resident assistance increased operative times but not complications. Counterbalanced effects of increasing skill and increasing participation may explain this time stability across PGY levels. Continuity of care is preserved in the era of the 80-hour workweek, but not to a patient-specific degree.

Verbal Aggressiveness Among Physicians and Trainees

OBJECTIVE

To better understand verbal aggressiveness among physicians and trainees, including specialty-specific differences.

DESIGN AND PARTICIPANTS

The Infante Verbal Aggressiveness Scale (IVAS) was administered as part of a survey to 48 medical students, 24 residents, and 257 attending physicians. The 72 trainees received the IVAS and demographic questions, whereas the attending physicians received additional questions regarding type of practice, career satisfaction, litigation, and personality type.

RESULTS

The IVAS scores showed high reliability (Cronbach α = 0.83). Among all trainees, 56% were female with mean age 28 years, whereas among attending physicians, 63% were male with mean age 50 years. Average scores of trainees were higher than attending physicians with corresponding averages of 1.88 and 1.68, respectively. Among trainees, higher IVAS scores were significantly associated with male sex, non-US birthplace, choice of surgery, and a history of bullying. Among attending physicians, higher IVAS scores were significantly associated with male sex, younger age, self-reported low-quality of patient-physician relationships, and low enjoyment talking to patients. General surgery and general internal medicine physicians were significantly associated with higher IVAS scores than other specialties. General practitioners (surgeons and medical physicians) had higher IVAS scores than the specialists in their corresponding fields. No significant correlation was found between IVAS scores and threats of legal action against attending physicians, or most personality traits. Additional findings regarding bullying in medical school, physician-patient interactions, and having a method to deal with inappropriate behavior at work were observed.

CONCLUSIONS

Individuals choosing general specialties display more aggressive verbal communication styles, general surgeons displaying the highest. The IVAS scoring system may identify subgroups of physicians with overly aggressive (problematic) communication skills and may provide a backdrop for educating physician communicators. The relationship between verbal aggressiveness and efficacy of clinical communication merits inquiry.

Laparoscopic Adrenalectomy for Adrenal Cancer-A Systematic Review

Laparoscopic adrenalectomy is increasingly employed for removal of adrenal masses. As adrenal tumors increase in size, however, their malignant potential likewise increases, raising concerns for the use of laparoscopy for removal of large adrenal malignancies. We present a systematic review of the use of laparoscopic adrenalectomy of large malignant tumors. A PubMed search was undertaken and two independent reviewers reviewed the manuscripts and a methodological index for nonrandomized studies score was determined. Manuscripts with scores greater than eight were included. The primary end points were rate of cancer recurrence, rate of conversion to open, complications, and surgical technique. Our initial search produced 412 manuscripts. After abstract review, 44 manuscripts were scored, of which 19 manuscripts were used. A total of 2183 tumors were removed, of which 517 were malignant. Average follow-up time was 38.7 months. The recurrence rate was 12.9 per cent. The rate of conversion was 3.6 per cent. The main techniques used were transabdominal and retroperitoneal. No significant differences in rate of recurrence or complications were seen when compared with open. Laparoscopic adrenalectomy may be performed for large and malignant tumors; however, most manuscripts on this subject lack significant scientific rigor and follow-up.

Laparoscopic Adrenalectomy for Adrenal Cancer—A Systematic Review

Laparoscopic adrenalectomy is increasingly employed for removal of adrenal masses. As adrenal tumors increase in size, however, their malignant potential likewise increases, raising concerns for the use of laparoscopy for removal of large adrenal malignancies. We present a systematic review of the use of laparoscopic adrenalectomy of large malignant tumors. A PubMed search was undertaken and two independent reviewers reviewed the manuscripts and a methodological index for nonrandomized studies score was determined. Manuscripts with scores greater than eight were included. The primary end points were rate of cancer recurrence, rate of conversion to open, complications, and surgical technique. Our initial search produced 412 manuscripts. After abstract review, 44 manuscripts were scored, of which 19 manuscripts were used. A total of 2183 tumors were removed, of which 517 were malignant. Average follow-up time was 38.7 months. The recurrence rate was 12.9 per cent. The rate of conversion was 3.6 per cent. The main techniques used were transabdominal and retroperitoneal. No significant differences in rate of recurrence or complications were seen when compared with open. Laparoscopic adrenalectomy may be performed for large and malignant tumors; however, most manuscripts on this subject lack significant scientific rigor and follow-up.

A Systematic Review of Perforated Appendicitis and Phlegmon: Interval Appendectomy or Wait-and-See?

Patients with appendiceal abscess or phlegmon have been traditionally managed with antibiotics and radiologically guided drainage of the abscess. Many studies have questioned the need for interval appendectomy. A systematic review of the nonsurgical treatment of patients with an appendiceal abscess or phlegmon was undertaken. The rate of recurrence after nonsurgical management, morbidity and length of hospital stay was measured. PubMed and Cochrane databases were queried to identify 21 studies reporting the morbidity of nonsurgical treatment of appendiceal phlegmon or abscess, and five studies reporting the morbidity of performing interval appendectomy. Repeat nonsurgical management was compared with that of performing interval appendectomy. The studies included a total of 1943 patients, of which 1400 patients were managed nonsurgically and 543 patients underwent interval appendectomy. Nonoperative treatment had a mean recurrence of 12.4 per cent, a morbidity of 13.3 per cent, and the length of hospital stay was 9.6 days. The mean morbidity rate and length of hospital stay for patients who underwent interval appendectomy was 10.4 per cent and 5.0 days, respectively. Interval appendectomy and repeat nonoperative management in case of recurrence are associated with similar morbidity; however, elective interval appendectomy implies additional operative costs to prevent recurrence in one of eight patients.

A Systematic Review of Perforated Appendicitis and Phlegmon: Interval Appendectomy or Wait-and-See?

Patients with appendiceal abscess or phlegmon have been traditionally managed with antibiotics and radiologically guided drainage of the abscess. Many studies have questioned the need for interval appendectomy. A systematic review of the nonsurgical treatment of patients with an appendiceal abscess or phlegmon was undertaken. The rate of recurrence after nonsurgical management, morbidity and length of hospital stay was measured. PubMed and Cochrane databases were queried to identify 21 studies reporting the morbidity of nonsurgical treatment of appendiceal phlegmon or abscess, and five studies reporting the morbidity of performing interval appendectomy. Repeat nonsurgical management was compared with that of performing interval appendectomy. The studies included a total of 1943 patients, of which 1400 patients were managed nonsurgically and 543 patients underwent interval appendectomy. Nonoperative treatment had a mean recurrence of 12.4 per cent, a morbidity of 13.3 per cent, and the length of hospital stay was 9.6 days. The mean morbidity rate and length of hospital stay for patients who underwent interval appendectomy was 10.4 per cent and 5.0 days, respectively. Interval appendectomy and repeat nonoperative management in case of recurrence are associated with similar morbidity; however, elective interval appendectomy implies additional operative costs to prevent recurrence in one of eight patients.

Energetic etiologies of acute pancreatitis: A report of five cases

There are several common causes of acute pancreatitis, principally excessive alcohol intake and gallstones, and there are many rare causes. However, cases of pancreatitis still occur in the absence of any recognizable factors, and these cases of idiopathic pancreatitis suggest the presence of unrecognized etiologies. Five cases of acute pancreatitis in four patients came to attention due to a strong temporal association with exposure to nerve stimulators and energy drinks. Given that these cases of pancreatitis were otherwise unexplained, and given that these exposures were not clearly known to be associated with pancreatitis, we performed a search for precedent cases and for mechanistic bases. No clear precedent cases were found in PubMed and only scant, weak precedent cases were found in public-health databases. However, there was a coherent body of intriguing literature in support of a mechanistic basis for these exposures playing a role in the etiology of pancreatitis.

Implications of gallbladder cholesterolosis and cholesterol polyps?

BACKGROUND

The clinical significance of cholesterolosis has not been well established but there are some provocative, if not robust, studies of the role it may play in the pathophysiology of pancreatitis and biliary dyskinesia, as well as hypercholesterolemia. Our aim was to take advantage of a very large cholecystectomy (CCY) database to support or refute these potentially important reported associations.

MATERIALS AND METHODS

A retrospective review of 6868 patients who underwent CCY from 2001-2013 was performed. Comparisons were made using the student t-test for continuous and chi-square analysis for categorical, variables.

RESULTS

Among patients for whom the CCY was the primary operation, 1053 (18%) had cholesterolosis and 4596 did not. Compared to those without cholesterolosis, those with cholesterolosis were no more likely to have elevated cholesterol levels (P = 0.64) nor low gallbladder ejection fraction (P = 0.2). To evaluate cholesterolosis as a cause of pancreatitis, all patients with gallstones were eliminated, leaving 639 patients. Among these, not only was cholesterolosis not associated with more pancreatitis, but rather there was not a single patient with or without cholesterolosis who had pancreatitis.

CONCLUSIONS

Despite prior reports of associations between cholesterolosis and elevated serum cholesterol, depressed ejection fraction, and increased risk of pancreatitis, careful analysis of this current, larger data set does not support these associations. Any patient with stones or sludge, or with biliary dyskinesia, and appropriate symptoms, should be considered for CCY, with or without suspected cholesterolosis.

Gallbladder dysfunction: how much longer will it be controversial?

BACKGROUND

Motility disorders of the biliary tree [biliary dyskinesia, including both gallbladder dysfunction (GBD), and sphincter of Oddi dysfunction] are difficult to diagnose and to treat.

SUMMARY

There is controversy in the literature in particular regarding the criteria that should be used to select patients for cholecystectomy (CCY) in cases of suspected GBD. The current review covers the history, diagnosis, and treatment of GBD. Key Messages: Only >85% of patients with suspected GBD have relief following CCY, a much lower rate than the nearly 100% success rate following CCY for gallstone disease. Unfortunately, the literature is lacking, and there are no universally agreed-upon criteria for selecting which patients to refer for operation, although cholecystokinin (CCK)-enhanced hepatobiliary iminodiacetic acid scan is often used, with emphasis on an abnormally low gallbladder ejection fraction or pain reproduction at CCK administration. There is a clear need for large, well-designed, more definitive, prospective studies to better identify the indications for and efficacy of CCY in cases of GBD.

Conventional Laparoscopic vs Robotic Training: Which is Better for Naive Users? A Randomized Prospective Crossover Study

OBJECTIVE

Robotic training (RT) using the da Vinci skills simulator and conventional training (CT) using a laparoscopic "training box" are both used to augment operative skills in minimally invasive surgery. The current study tests the hypothesis that skill acquisition is more rapid using RT than using CT among naive learners.

DESIGN AND PARTICIPANTS

A total of 40 subjects without laparoscopic or robotic surgical experience were enrolled and randomized to begin with either RT or CT. Then, 2 specific RT tasks were reproduced for CT and repeated 5 times each with RT and CT. Time and quality indicators were measured quantitatively. A crossover technique was used to control for in-study experience bias.

RESULTS

The tasks "pick and place jacks" (PP) and "thread the rings" (TR) were achieved faster with RT than with CT despite crossover (p < 0.0001). An RT-favoring difference was observed in speed for both tasks when changing modality. Percentage improvement with increasing trials was similar for RT and CT: RT completion time averaged 39 seconds and 211 seconds (PP and TR, respectively), compared with 65 seconds and 362 seconds when using CT (p < 0.0001); final improvement averaged 26% and 46% for RT (PP and TR, respectively) vs 31% and 47% for CT (p was 0.76 for PP and 0.20 for TR). Within the PP task, RT times averaged 41 seconds without previous CT experience vs 35 seconds with previous CT experience (p = 0.20); CT times averaged 61 seconds without and 69 seconds with previous RT experience (p = 0.48). Comparable times for the TR task were 212 seconds vs 216 seconds (p = 0.66) and 388 seconds vs 334 seconds (p = 0.17). Both instrument collisions and excessive force occurred more commonly for RT than for CT within the TR task (p < 0.0001).

CONCLUSIONS

Speeds were faster overall with RT than with CT, but the percentage of speed improvement with trials was similar, suggesting similar learning curves, with minimal transfer effect appreciated.

Predicting gangrenous cholecystitis

BACKGROUND

Gangrenous cholecystitis (GC) is often challenging to treat. The objectives of this study were to determine the accuracy of pre-operative diagnosis, to assess the rate of post-cholecystectomy complications and to assess models to predict GC.

METHODS

A retrospective single-institution review identified patients undergoing a cholecystectomy. Logistic regression models were used to examine the association of variables with GC and to build risk-assessment models.

RESULTS

Of 5812 patients undergoing a cholecystectomy, 2219 had acute, 4837 chronic and 351 GC. Surgeons diagnosed GC pre-operatively in only 9% of cases. Patients with GC had more complications, including bile-duct injury, increased estimated blood loss (EBL) and more frequent open cholecystectomies. In unadjusted analyses, variables significantly associated with GC included: age >45 years, male gender, heart rate (HR) >90, white blood cell count (WBC) >13,000/mm(3), gallbladder wall thickening (GBWT) ≥ 4 mm, pericholecystic fluid (PCCF) and American Society of Anesthesiology (ASA) >2. In adjusted analyses, age, WBC, GBWT and HR, but not gender, PCCF or ASA remained statistically significant. A 5-point scoring system was created: 0 points gave a 2% probability of GC and 5 points a 63% probability.

CONCLUSION

Using models can improve a diagnosis of GC pre-operatively. A prediction of GC pre-operatively may allow surgeons to be better prepared for a difficult operation.

Minimally invasive treatment of colorectal liver metastases

Minimally invasive approaches are increasingly used in the treatment of colorectal liver metastases (CRLMs) and for increasingly complex cases. Herein, we review the spectrum of modalities used in the minimally invasive treatment of CRLM, focusing on one of the newest approaches, robotic liver resection, and on local regional therapies, both operative and percutaneous. Oncologic outcomes after minimally invasive therapies are also evaluated. Although there are no randomized trials comparing minimally invasive liver resection to open resection, an increasing quantity of nonrandomized data suggest favorable outcomes with a minimally invasive approach. The future of minimally invasive treatment of CRLM will likely include specifying training and credentialing criteria as well as an enlarging role for the combined surgical treatment of CRLM and extrahepatic colorectal metastases.

Cancer surgery in the elderly

The proportions both of elderly patients in the world and of elderly patients with cancer are both increasing. In the evaluation of these patients, physiologic age, and not chronologic age, should be carefully considered in the decision-making process prior to both cancer screening and cancer treatment in an effort to avoid ageism. Many tools exist to help the practitioner determine the physiologic age of the patient, which allows for more appropriate and more individualized risk stratification, both in the pre- and postoperative periods as patients are evaluated for surgical treatments and monitored for surgical complications, respectively. During and after operations in the oncogeriatric populations, physiologic changes occuring that accompany aging include impaired stress response, increased senescence, and decreased immunity, all three of which impact the risk/benefit ratio associated with cancer surgery in the elderly.

Non-dialysis-dependent renal dysfunction and cardiac surgery-an assessment of perioperative risk factors

OBJECTIVE

In most reports, dialysis-dependent patients are known to be at increased risk for perioperative morbidity and mortality after cardiac surgical procedures.(1-7) However, the preoperative factors important for risk stratification of patients who have renal insufficiency but are not dialysis dependent are unclear. We set forth to ascertain preoperative risk factors important for predicting 2 endpoints: (1) dialysis at discharge and (2) hospital death.

DESIGN

A retrospective analysis.

SETTING

A tertiary referral center.

PATIENTS

From a database of patients undergoing cardiopulmonary bypass over a 6-year period, 150 patients were chosen for study based on their preoperative creatinine being greater than 1.5 mg/dl.

INTERVENTIONS

Routine monitoring and care of patients after their cardiac surgical procedures.

MEASUREMENTS AND MAIN RESULTS

Many preoperative, perioperative, and postoperative variables were measured. Multivariable regression was used for data analysis. There were 21 (14%) hospital deaths and 7 (5%) patients who were not on preoperative dialysis who required dialysis at discharge. Preoperative risk factors for hospital death were the patients' New York Heart Association (NYHA) class (p = 0.004) and emergency status (p = 0.005). Preoperative risk factors for dialysis at discharge were female gender (p = 0.02), emergency status of procedure (p = 0.01), and preoperative creatinine (p = 0.03).

CONCLUSIONS

These data allow for a more accurate assessment of risk stratification in this group of patients with renal insufficiency but who are not dependent on dialysis. Given the data presented here and other studies that report good outcomes for patients with renal disease after cardiac surgical procedures,(8-10) earlier operative intervention for coronary disease in this subset of patients might be warranted.

Anion, cation, and zwitterion selectivity of phospholemman channel molecules

Phospholemman (PLM), a 72-amino acid membrane protein with a single transmembrane domain, forms taurine-selective ion channels in lipid bilayers. Because taurine forms zwitterions, a taurine-selective channel might have binding sites for both anions and cations. Here we show that PLM channels indeed allow fluxes of both cations and anions, making instantaneous and voltage-dependent transitions among conformations with drastically different ion selectivity characteristics. This surprising and novel ion channel behavior offers a molecular explanation for selective taurine flux across cell membranes and may explain why molecules in the phospholemman family can induce cation- or anion-selective conductances when expressed in Xenopus oocytes.

Unitary anion currents through phospholemman channel molecules

Phospholemman (PLM) is a 72-amino-acid peptide with a single transmembrane domain, the expression of which induces chloride currents in Xenopus oocytes. It has remained unknown whether PLM is an ion channel or acts as a channel regulator. Here we show, by measuring unitary anion currents across planar phospholipid bilayers to which immunoaffinity-purified recombinant PLM was added, that it does indeed form ion channels. Excised patches of oocytes expressing PLM had similar currents. Of the ions tested, the sulphonic amino acid taurine was the most permeant, and expression of PLM increased fluxes of radiolabelled taurine in oocytes. Phospholemman is the smallest protein in cell membranes known to form an ion channel and the taurine selectivity suggests that it is involved in cell volume regulation.

Mat-8, a novel phospholemman-like protein expressed in human breast tumors, induces a chloride conductance in Xenopus oocytes

We recently identified a novel 8-kDa transmembrane protein, Mat-8, that is expressed in a subset of murine breast tumors. We have now cloned a cDNA encoding the human version of Mat-8 and show that it is expressed both in primary human breast tumors and in human breast tumor cell lines. The extracellular and transmembrane domains of Mat-8 are homologous to those of phospholemman (PLM), the major plasmalemmal substrate for cAMP-dependent protein kinase and protein kinase C in several different tissues. PLM, which induces chloride currents when expressed in Xenopus oocytes, contains consensus phosphorylation sites for both cAMP-dependent protein kinase A and protein kinase C in its cytoplasmic domain. In contrast, the cytoplasmic domain of Mat-8 contains no such consensus phosphorylation sites and is, in fact, unrelated to the cytoplasmic domain of PLM. RNA blot analysis reveals that Mat-8 and PLM exhibit distinct tissue-specific patterns of expression. We show that expression of Mat-8 in Xenopus oocytes induces hyperpolarization-activated chloride currents similar to those induced by PLM expression. These findings suggest that Mat-8 and PLM, the products of distinct genes, are related proteins that serve as Cl- channels or Cl- channel regulators but have different roles in cell and organ physiology.

Hyperpolarization-activated chloride currents in Xenopus oocytes

During hyperpolarizing pulses, defolliculated Xenopus oocytes have time- and voltage-dependent inward chloride currents. The currents vary greatly in amplitude from batch to batch; activate slowly and, in general, do not decay; have a selectivity sequence of I- > NO3- > Br- > Cl- > propionate > acetate; are insensitive to Ca2+ and pH; are blocked by Ba2+ and some chloride channel blockers; and have a gating valence of approximately 1.3 charges. In contrast to hyperpolarization-activated chloride currents induced after expression of phospholemman (Palmer, C. J., B. T. Scott, and L. R. Jones. 1991. Journal of Biological Chemistry. 266:11126; Moorman, J. R., C. J. Palmer, J. E. John, J. E. Durieux, and L. R. Jones. 1992. 267:14551), these endogenous currents are smaller; have a different pharmacologic profile; have a lower threshold for activation and lower voltage-sensitivity of activation; have different activation kinetics; and are insensitive to pH. Nonetheless, the endogenous and expressed current share striking similarities. Recordings of macroscopic oocyte currents may be inadequate to determine whether phospholemman is itself an ion channel and not a channel-modulating molecule.