A breath of fresh air: a quality-improvement study comparing an air-circulating technique versus conventional technique to prevent nasogastric tube dysfunction

Background

Nasogastric tubes are an important component of care in patients with gastrointestinal obstructions. However, they are prone to malfunction despite conventional flushing techniques, with potentially severe consequences. There is no widely accepted, gold-standard way to ensure that a nasogastric tube succeeds in maintaining an empty stomach following flushing.

Methods

We have developed a flushing technique to better ensure successful tube function. We compared this technique to conventional flushing both in vitro (using a plastic stomach model) and in vivo (in a pig model), and we provide a didactic video.

Results

The mean gastric residual volume following our novel flushing technique is nearly 25-fold lower than following conventional flushing (13 mL vs. 330 mL).

Conclusions

Our simple technique is more effective than conventional techniques in maintaining nasogastric tube function and therefore should prevent dangerous vomiting and aspiration pneumonia better than conventional techniques.

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.

Transient suppression of hepatocellular replication in the mouse liver following transduction with recombinant adeno-associated virus

Recombinant vectors based on adeno-associated virus (AAV) are proving to be powerful tools for genetic manipulation of the liver, for both discovery and therapeutic purposes. The system can be used to deliver transgene cassettes for expression or, alternatively, DNA templates for genome editing via homologous recombination. The replicative state of target cells is known to influence the efficiency of these processes and knowledge of the host-vector interactions involved is required for optimally effective vector deployment. Here we show, for the first time in vivo, that in addition to the known effects of hepatocellular replication on AAV-mediated gene transfer, the vector itself exerts a potent, albeit transient suppressive effect on cell cycle progression that is relieved on a time course that correlates with the known rate of clearance of input single-stranded vector DNA. This finding requires further mechanistic investigation, delineates an excellent model system for such studies and further deepens our insight into the complexity of interactions between AAV vectors and the cell cycle in a clinically promising target tissue.

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.

Necrotizing pancreatitis: a review of multidisciplinary management

The objective of this review is to summarize the current state of the art of the management of necrotizing pancreatitis, and to clarify some confusing points regarding the terminology and diagnosis of necrotizing pancreatitis, as these points are essential for management decisions and communication between providers and within the literature. Acute pancreatitis varies widely in its clinical presentation. Despite the publication of the Atlanta guidelines, misuse of pancreatitis terminology continues in the literature and in clinical practice, especially regarding the local complications associated with severe acute pancreatitis. Necrotizing pancreatitis is a manifestation of severe acute pancreatitis associated with significant morbidity and mortality. Diagnosis is aided by pancreas-protocol computed tomography or magnetic resonance imaging, ideally 72 h after onset of symptoms to achieve the most accurate characterization of pancreatic necrosis. The extent of necrosis correlates well with the incidence of infected necrosis, organ failure, need for debridement, and morbidity and mortality. Having established the diagnosis of pancreatic necrosis, goals of appropriately aggressive resuscitation should be established and adhered to in a multidisciplinary approach, ideally at a high-volume pancreatic center. The role of antibiotics is determined by the presence of infected necrosis. Early enteral feeds improve outcomes compared with parenteral nutrition. Pancreatic necrosis is associated with a multitude of complications which can lead to long-term morbidity or mortality. Interventional therapy should be guided by available resources and the principle of a minimally invasive approach. When open debridement is necessary, it should be delayed at least 3-6 weeks to allow demarcation of necrotic from viable tissue.

Gene-specific selection against experimental fanconi anemia gene inactivation in human cancer

The Fanconi anemia (FA) gene family comprises at least 12 genes interacting in a common pathway involved in DNA repair. To gain insight into the role of FA gene inactivation occurring in tumors among the general population, we endogenously targeted in cancer cells four FA genes that act at different stages of the FA pathway. After successful mono-allelic deletion of all genes, the sequential homozygous deletion was achieved only for FANCC and FANCG, acting upstream, but not for BRCA2 or FANCD2, acting downstream in the FA pathway. Targeting of the second allele in in BRCA2 and FANCD2 heterozygote clones resulted in redeletion exclusively of the already defective allele in multiple instances (13x concerning BRCA2, 25x concerning FANCD2), strongly suggesting a detrimental phenotype. Unlike complete FANCD2 disruption, the mere reduction of FANCD2 protein levels had no discernible effect. In addition, we confirmed that human cancer cells harboring the Seckel ATR mutation display impaired FANCD2 monoubiquitination and FANCD2 nuclear focus formation, as well as an increased sensitivity to DNA interstrand-crosslinking agents. Nevertheless, these cells were viable, indicating an ATR-independent function of FANCD2, distinct from its major known functions, to be responsible for the detrimental effects of FANCD2 loss. In conclusion, we established the downstream FA genes FANCD2 and BRCA2 to represent particularly vulnerable parts of the FA pathway, providing direct evidence for the paradoxical assumption that their inactivation could be predominantly selected against in cancer cells. This would explain why certain FA gene defects, despite an apparent selection for FA pathway inactivation in cancer, are rarely observed in tumors among the general population.

Hemosuccus pancreaticus due to a noninflammatory pancreatic pseudotumor

CONTEXT

Hemosuccus pancreaticus is a rare source of gastrointestinal bleeding, the most frequent cause of which is pancreatitis, followed by tumors, but nearly all these tumors are true neoplasms, and not pseudotumors. Furthermore, nearly all pseudotumors of the pancreas and retroperitoneum are inflammatory.

CASE REPORT

We present a case of hemosuccus pancreaticus associated with a nonneoplastic noninflammatory pseudotumor of the pancreas.

CONCLUSIONS

Pancreatic pseudotumors are not always inflammatory and should be considered in the differential diagnosis of gastrointestinal bleeding associated with hemosuccus pancreaticus.

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.

Massive splenomegaly correlates with malignancy: 180 cases of splenic littoral cell tumors in the world literature

Littoral cell tumors (LCT) are rare primary splenic neoplasms, unique for their morphologic and immunolabeling features resembling the endothelial littoral cells lining the sinusoids of the red pulp. They include the more common and typically benign littoral cell angioma, as well as the less common, potentially malignant, littoral cell hemangioendothelioma (LCHE) and the aggressive littoral cell angiosarcoma (LCAS). The most common presentation of these neoplasms is splenomegaly, and diagnosis is made histologically following biopsy or resection. To better understand these tumors, a comprehensive, international literature search was performed. Patient and tumor data, including presenting symptoms, comorbid cancers, immunosuppressive states, splenic mass and tumor size were analyzed. Massive splenomegaly (≥ 1500 g) following splenic resection, which correlates with a splenic length of 20 cm preoperatively, was found to be significantly associated with the presence of malignancy in the LCT (P<0.05).

A rapid, controlled-environment seedling root screen for wheat correlates well with rooting depths at vegetative, but not reproductive, stages at two field sites

BACKGROUND AND AIMS

Root length and depth determine capture of water and nutrients by plants, and are targets for crop improvement. Here we assess a controlled-environment wheat seedling screen to determine speed, repeatability and relatedness to performance of young and adult plants in the field.

METHODS

Recombinant inbred lines (RILs) and diverse genotypes were grown in rolled, moist germination paper in growth cabinets, and primary root number and length were measured when leaf 1 or 2 were fully expanded. For comparison, plants were grown in the field and root systems were harvested at the two-leaf stage with either a shovel or a soil core. From about the four-leaf stage, roots were extracted with a steel coring tube only, placed directly over the plant and pushed to the required depth with a hydraulic ram attached to a tractor.

KEY RESULTS

In growth cabinets, repeatability was greatest (r = 0.8, P < 0.01) when the paper was maintained moist and seed weight, pathogens and germination times were controlled. Scanned total root length (slow) was strongly correlated (r = 0.7, P < 0.01) with length of the two longest seminal axile roots measured with a ruler (fast), such that 100-200 genotypes were measured per day. Correlation to field-grown roots at two sites at two leaves was positive and significant within the RILs and cultivars (r = 0.6, P = 0.01), and at one of the two sites at the five-leaf stage within the RILs (r = 0.8, P = 0.05). Measurements made in the field with a shovel or extracted soil cores were fast (5 min per core) and had significant positive correlations to scanner measurements after root washing and cleaning (>2 h per core). Field measurements at two- and five-leaf stages did not correlate with root depth at flowering.

CONCLUSIONS

The seedling screen was fast, repeatable and reliable for selecting lines with greater total root length in the young vegetative phase in the field. Lack of significant correlation with reproductive stage root system depth at the field sites used in this study reflected factors not captured in the screen such as time, soil properties, climate variation and plant phenology.

Pneumatosis and portal venous gas: do CT findings reassure?

BACKGROUND

Small, single-institution studies have suggested risk factors for bowel ischemia/necrosis (I/N) in patients with computed tomography (CT) findings of pneumatosis (PN) and portal venous gas (PVG). Here, analysis has been expanded in a large, multicenter study.

MATERIALS & METHODS

Logistic regression models and receiver operating characteristic curves were used to construct a scoring system for I/N in cases of PN/PVG.

RESULTS

Of 265 patients with PN/PVG identified, 209 had adequate data. In unadjusted analyses the following variables were significantly associated with I/N: age, peritoneal signs, ascites, the presence of both PVG and PN, blood urea nitrogen (BUN), CO2, albumin, and a history of hypertension, myocardial infarction, or stroke. In contrast, the CT findings of mesenteric stranding, bowel-wall thickening, and type of PN were not associated with I/N. In adjusted analyses, three variables were significantly associated with I/N: age ≥60 y (odds ratio = 2.51, 95% confidence interval: 1.26-4.97), peritoneal signs (10.58, 4.23-26.4), and BUN >25 mg/dL (3.08, 1.54-6.17), whereas presence of both PN and PVG (versus only one) was associated with an increase (but not statistically significant increase) in odds (2.01, 0.94-4.36). Although several ad hoc models were used to maximize diagnostic ability, with maximal odds ratio = 174, the areas of receiver operating characteristic curves were all below 0.80, revealing suboptimal accuracy to diagnose I/N.

CONCLUSIONS

Older age, peritoneal signs, and high BUN are associated with I/N, suggesting an ability to predict which patients need operation. CT findings traditionally suggestive of ischemic PN/PVG, however, do not diagnose I/N accurately enough to reliably identify patients needing 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.

Hepatic gas: widening spectrum of causes detected at CT and US in the interventional era

The spectrum of causes of hepatic gas detected at computed tomography (CT) and ultrasonography (US) is widening. There are many iatrogenic and noniatrogenic causes of hepatic parenchymal, biliary, hepatic venous, and portal venous gas. Hepatic gas may be an indicator of serious acute disease (infarct, infection, abscess, bowel inflammation, or trauma). In other clinical scenarios, it may be an expected finding related to therapeutic interventions (such as surgery; hepatic artery embolization for a tumor or for active bleeding in acute trauma cases; percutaneous tumor ablation performed with radiofrequency, cryotherapy, laser photocoagulation, or ethanol). In some cases, hepatic gas is an incidental finding of no clinical significance. Familiarity with the expanding list of newer intervention-related causes of hepatic gas detected at CT and US, knowledge of the patient's clinical history, and a careful search for associated clues on images are all factors that may allow the radiologist to better determine the clinical relevance of this finding.

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.