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1.
Contraindications and adverse effects in abdominal imaging.
Caraiani, C, Petresc, B, Dong, Y, Dietrich, CF
Medical ultrasonography. 2019;(4):456-463
Abstract
Ultrasound (US), computed-tomography (CT) and magnetic resonance imaging (MRI) are the most frequently used imaging techniques in abdominal pathology. US plays a pivotal role in evaluating abdominal disease, sometimes being sufficient for a complete diagnosis and has virtually no contraindications. The usage of US contrast agents will add useful diagnostic information in both hepatic and non-hepatic pathology. CT has, over MRI, the advantage of being readily available. The usage of ionizing radiation is the main pitfall of CT. Allergies and contrast induced nephropathy in patients with an impaired renal function are the major risks of contrast media administration in CT. Its excellent tissue resolution makes MRI a very useful technique in abdominal pathology, the major contraindications being the presence of MRI "unsafe" implants and devices and the presence of metallic foreign bodies, particularly close to vital structures like the eyes or major vessels. Contrast administration in MRI is restricted in patients with renal insufficiency due to the risk of nephrogenic systemic fibrosis. Allergies to MRI contrast media are rare and less important compared to allergies due to CT contrast media.
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2.
Dual-Energy CT in Evaluation of the Acute Abdomen.
Murray, N, Darras, KE, Walstra, FE, Mohammed, MF, McLaughlin, PD, Nicolaou, S
Radiographics : a review publication of the Radiological Society of North America, Inc. 2019;(1):264-286
Abstract
Evaluation of the nontraumatic acute abdomen with multidetector CT has long been accepted and validated as the reference standard in the acute setting. Dual-energy CT has emerged as a promising tool, with multiple clinical applications in abdominal imaging already demonstrated. With its ability to allow characterization of materials on the basis of their differential attenuation when imaged at two different energy levels, dual-energy CT can help identify the composition of internal body constituents. Therefore, it is possible to selectively identify iodine to assess the enhancement pattern of an organ, including the identification of hyperenhancement in cases of inflammatory processes, or ischemic changes secondary to vascular compromise. Quantification of iodine uptake with contrast material-enhanced dual-energy CT is also possible, and this quantification has been suggested to be useful in differentiating inflammatory from neoplastic conditions. Dual-energy CT can help determine the composition of gallstones and urolithiasis and can be used to accurately differentiate uric acid urinary calculi from non-uric acid urinary calculi. Moreover, dual-energy CT is capable of substantially reducing artifacts caused by metallic prostheses, to improve the imaging evaluation of abdominopelvic organs. The possibility of creating virtual nonenhanced images in the evaluation of acute aortic syndrome, gastrointestinal hemorrhage and ischemia, or pancreatic pathologic conditions substantially reduces the radiation dose delivered to the patient, by eliminating a true nonenhanced acquisition. Finally, by increasing the iodine conspicuity, contrast-enhanced dual-energy CT can render an area of free active extravasation or endoleak more visible, compared with conventional single-energy CT. This article reviews the basics of dual-energy CT and highlights its main clinical applications in evaluation of the nontraumatic acute abdomen. ©RSNA, 2019.
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3.
Imaging with ultrasound contrast agents: current status and future.
Chong, WK, Papadopoulou, V, Dayton, PA
Abdominal radiology (New York). 2018;(4):762-772
Abstract
Microbubble ultrasound contrast agents (UCAs) were recently approved by the Food and Drug administration for non-cardiac imaging. The physical principles of UCAs, methods of administration, dosage, adverse effects, and imaging techniques both current and future are described. UCAs consist of microbubbles in suspension which strongly interact with the ultrasound beam and are readily detectable by ultrasound imaging systems. They are confined to the blood pool when administered intravenously, unlike iodinated and gadolinium contrast agents. UCAs have a proven safety record based on over two decades of use, during which they have been used in echocardiography in the U.S. and for non-cardiac imaging in the rest of the world. Adverse effects are less common with UCAs than CT/MR contrast agents. Compared to CT and MR, contrast-enhanced ultrasound has the advantages of real-time imaging, portability, and reduced susceptibility to metal and motion artifact. UCAs are not nephrotoxic and can be used in renal failure. High acoustic amplitudes can cause microbubbles to fragment in a manner that can result in short-term increases in capillary permeability or capillary rupture. These bioeffects can be beneficial and have been used to enhance drug delivery under appropriate conditions. Imaging with a mechanical index of < 0.4 preserves the microbubbles and is not typically associated with substantial bioeffects. Molecularly targeted ultrasound contrast agents are created by conjugating the microbubble shell with a peptide, antibody, or other ligand designed to target an endothelial biomarker associated with tumor angiogenesis or inflammation. These microbubbles then accumulate in the microvasculature at target sites where they can be imaged. Ultrasound contrast agents are a valuable addition to the diagnostic imaging toolkit. They will facilitate cross-sectional abdominal imaging in situations where contrast-enhanced CT and MR are contraindicated or impractical.
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4.
The Impact of Total Body Prehabilitation on Post-Operative Outcomes After Major Abdominal Surgery: A Systematic Review.
Luther, A, Gabriel, J, Watson, RP, Francis, NK
World journal of surgery. 2018;(9):2781-2791
Abstract
BACKGROUND Despite advances in perioperative care, post-operative clinical and functional outcomes after major abdominal surgery can be suboptimal. Prehabilitation programmes attempt to optimise a patient's preoperative condition to improve outcomes. Total body prehabilitation includes structured exercise, nutritional optimisation, psychological support and cessation of negative health behaviours. This systematic review aims to report on the current literature regarding the impact of total body prehabilitation prior to major abdominal surgery. METHODS Relevant studies published between January 2000 and July 2017 were identified using MEDLINE, EMBASE, AMED, CINAHL, PsychINFO, PubMed, and the Cochrane Database. All studies published in a peer-reviewed journal, assessing post-operative clinical and functional outcomes, following a prehabilitation programme prior to major abdominal surgery were included. Studies with less than ten patients, or a prehabilitation programme lasting less than 7 days were excluded. RESULTS Sixteen studies were included, incorporating 2591 patients, with 1255 undergoing a prehabilitation programme. The studies were very heterogeneous, with multiple surgical sub-specialties, prehabilitation techniques, and outcomes assessed. Post-operative complication rate was reduced in six gastrointestinal studies utilising either preoperative exercise, nutritional supplementation in malnourished patients or smoking cessation. Improved functional outcomes were observed following a multimodal prehabilitation programme. Compliance was variably measured across the studies (range 16-100%). CONCLUSIONS There is substantial heterogeneity in the prehabilitation programmes used prior to major abdominal surgery. A multimodal approach is likely to have better impact on functional outcomes compared to single modality; however, there is insufficient data either to identify the optimum programme, or to recommend routine clinical implementation.
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5.
Meta-analysis of immunonutrition in major abdominal surgery.
Probst, P, Ohmann, S, Klaiber, U, Hüttner, FJ, Billeter, AT, Ulrich, A, Büchler, MW, Diener, MK
The British journal of surgery. 2017;(12):1594-1608
Abstract
BACKGROUND The objective of this study was to evaluate the potential benefits of immunonutrition in major abdominal surgery with special regard to subgroups and influence of bias. METHODS A systematic literature search from January 1985 to July 2015 was performed in MEDLINE, Embase and CENTRAL. Only RCTs investigating immunonutrition in major abdominal surgery were included. Outcomes evaluated were mortality, overall complications, infectious complications and length of hospital stay. The influence of different domains of bias was evaluated in sensitivity analyses. Evidence was rated according to the GRADE Working Group grading of evidence. RESULTS A total of 83 RCTs with 7116 patients were included. Mortality was not altered by immunonutrition. Taking all trials into account, immunonutrition reduced overall complications (odds ratio (OR) 0·79, 95 per cent c.i. 0·66 to 0·94; P = 0·01), infectious complications (OR 0·58, 0·51 to 0·66; P < 0·001) and shortened hospital stay (mean difference -1·79 (95 per cent c.i. -2·39 to -1·19) days; P < 0·001) compared with control groups. However, these effects vanished after excluding trials at high and unclear risk of bias. Publication bias seemed to be present for infectious complications (P = 0·002). Non-industry-funded trials reported no positive effects for overall complications (OR 1·13, 0·88 to 1·46; P = 0·34), whereas those funded by industry reported large effects (OR 0·66, 0·48 to 0·91; P = 0·01). CONCLUSION Immunonutrition after major abdominal surgery did not seem to alter mortality (GRADE high quality of evidence). Immunonutrition reduced overall complications, infectious complications and shortened hospital stay (GRADE low to moderate). The existence of bias lowers confidence in the evidence (GRADE approach).
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6.
Restrictive and liberal fluid administration in major abdominal surgery.
Pang, Q, Liu, H, Chen, B, Jiang, Y
Saudi medical journal. 2017;(2):123-131
Abstract
To determine whether perioperative fluid restrictive administration can reduce specific postoperative complications in adults undergoing major abdominal surgery. Methods: We searched the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials, Google scholar, and article reference lists (up to December 2015) for studies that assessed fluid therapy and morbidity or mortality in patients undergoing major abdominal surgeries. The quality of the trials was assessed using the Jadad scoring system, and a meta-analysis of the included randomized, controlled trials was conducted using Review Manager software, version 5.2. Results: Ten studies with a total of 1160 patients undergoing major abdominal surgeries were included. We found that perioperative restrictive fluid therapy could reduce the risk of postoperative infectious complications (odds ratio [OR]=0.54, 95% confidence interval [CI]: 0.39-0.74, p=0.0001, I2=37%), pulmonary complications (OR=0.49, 95% CI: 0.26-0.93, p=0.03, I2=50%), and cardiac complications (OR=0.45, 95% CI: 0.29-0.69, p=0.0003, I2=48%), but had no effect on the risk of gastrointestinal complications (OR=0.87, 95% CI: 0.51-1.46, p=0.59, I2=0%), renal complications (OR=0.76, 95% CI: 0.43-1.34, p=0.35, I2=0%), and postoperative mortality (OR=0.62, 95% CI: 0.25-1.50, p=0.29, I2=0%). Conclusion: Perioperative restrictive fluid administration was superior to liberal fluid administration in reducing the infectious, pulmonary and cardiac complications after major abdominal surgeries.
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7.
Effect of perioperative goal-directed hemodynamic therapy on postoperative recovery following major abdominal surgery-a systematic review and meta-analysis of randomized controlled trials.
Sun, Y, Chai, F, Pan, C, Romeiser, JL, Gan, TJ
Critical care (London, England). 2017;(1):141
Abstract
BACKGROUND Goal-directed hemodynamic therapy (GDHT) has been used in the clinical setting for years. However, the evidence for the beneficial effect of GDHT on postoperative recovery remains inconsistent. The aim of this systematic review and meta-analysis was to evaluate the effect of perioperative GDHT in comparison with conventional fluid therapy on postoperative recovery in adults undergoing major abdominal surgery. METHODS Randomized controlled trials (RCTs) in which researchers evaluated the effect of perioperative use of GDHT on postoperative recovery in comparison with conventional fluid therapy following abdominal surgery in adults (i.e., >16 years) were considered. The effect sizes with 95% CIs were calculated. RESULTS Forty-five eligible RCTs were included. Perioperative GDHT was associated with a significant reduction in short-term mortality (risk ratio [RR] 0.75, 95% CI 0.61-0.91, p = 0.004, I 2 = 0), long-term mortality (RR 0.80, 95% CI 0.64-0.99, p = 0.04, I 2 = 4%), and overall complication rates (RR 0.76, 95% CI 0.68-0.85, p < 0.0001, I 2 = 38%). GDHT also facilitated gastrointestinal function recovery, as demonstrated by shortening the time to first flatus by 0.4 days (95% CI -0.72 to -0.08, p = 0.01, I 2 = 74%) and the time to toleration of oral diet by 0.74 days (95% CI -1.44 to -0.03, p < 0.0001, I 2 = 92%). CONCLUSIONS This systematic review of available evidence suggests that the use of perioperative GDHT may facilitate recovery in patients undergoing major abdominal surgery.
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8.
Outcomes of abdominal surgery in patients with liver cirrhosis.
Lopez-Delgado, JC, Ballus, J, Esteve, F, Betancur-Zambrano, NL, Corral-Velez, V, Mañez, R, Betbese, AJ, Roncal, JA, Javierre, C
World journal of gastroenterology. 2016;(9):2657-67
Abstract
Patients suffering from liver cirrhosis (LC) frequently require non-hepatic abdominal surgery, even before liver transplantation. LC is an important risk factor itself for surgery, due to the higher than average associated morbidity and mortality. This high surgical risk occurs because of the pathophysiology of liver disease itself and to the presence of contributing factors, such as coagulopathy, poor nutritional status, adaptive immune dysfunction, cirrhotic cardiomyopathy, and renal and pulmonary dysfunction, which all lead to poor outcomes. Careful evaluation of these factors and the degree of liver disease can help to reduce the development of complications both during and after abdominal surgery. In the emergency setting, with the presence of decompensated LC, alcoholic hepatitis, severe/advanced LC, and significant extrahepatic organ dysfunction conservative management is preferred. A multidisciplinary, individualized, and specialized approach can improve outcomes; preoperative optimization after risk stratification and careful management are mandatory before surgery. Laparoscopic techniques can also improve outcomes. We review the impact of LC on surgical outcome in non-hepatic abdominal surgeries required in this cirrhotic population before, during, and after surgery.
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9.
Enteral nutrition versus parenteral nutrition after major abdominal surgery in patients with gastrointestinal cancer: a systematic review and meta-analysis.
Zhao, XF, Wu, N, Zhao, GQ, Liu, JF, Dai, YF
Journal of investigative medicine : the official publication of the American Federation for Clinical Research. 2016;(5):1061-74
Abstract
To clarify the benefits of enteral nutrition (EN) versus total parenteral nutrition (TPN) in patients with gastrointestinal cancer who underwent major abdominal surgery. Medline, Cochrane, EMBASE, and Google Scholar were searched for studies published until July 10, 2015, reporting outcomes between the two types of postoperative nutritional support. Only randomized controlled trials (RCTs) were included. A χ(2)-based test of homogeneity was performed using Cochran's Q statistic and I(2) A total of 2540 patients (1268 who received EN and 1272 who received TPN; average age range: 58.3-67.7 years) from 18 RCTs were included for assessment. Patients who received EN had shorter lengths of hospital stay (pooled difference in mean=-1.74, 95% CI -2.41 to -1.07, p<0.001, shorter time to flatus (pooled difference in mean=-1.27, 95% CI -1.69 to -0.85, p<0.001), and significantly greater increases in albumin levels (pooled difference in mean=-1.33, 95% CI -2.18 to -0.47, p=0.002) compared with those who received TPN after major abdominal surgery, based on a random-effects model of analysis. EN after major abdominal surgery provided better outcomes compared with TPN in patients with gastrointestinal cancer.
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10.
Enhanced recovery pathways in abdominal gynecologic surgery: a systematic review and meta-analysis.
de Groot, JJ, Ament, SM, Maessen, JM, Dejong, CH, Kleijnen, JM, Slangen, BF
Acta obstetricia et gynecologica Scandinavica. 2016;(4):382-95
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Abstract
INTRODUCTION Enhanced recovery pathways have been widely accepted and implemented for different types of surgery. Their overall effect in abdominal gynecologic surgery is still underdetermined. A systematic review and meta-analysis were performed to provide an overview of current evidence and to examine their effect on postoperative outcomes in women undergoing open gynecologic surgery. MATERIAL AND METHODS Searches were conducted using Embase, Medline, CINAHL, and the Cochrane Library up to 27 June 2014. Reference lists were screened to identify additional studies. Studies were included if at least four individual items of an enhanced recovery pathway were described. Outcomes included length of hospital stay, complication rates, readmissions, and mortality. Quantitative analysis was limited to comparative studies. Effect sizes were presented as relative risks or as mean differences (MD) with 95% confidence intervals (CI). RESULTS Thirty-one records, involving 16 observational studies, were included. Diversity in reported elements within studies was observed. Preoperative education, early oral intake, and early mobilization were included in all pathways. Five studies, with a high risk of bias, were eligible for quantitative analysis. Enhanced recovery pathways reduced primary (MD -1.57 days, 95% CI CI -2.94 to -0.20) and total (MD -3.05 days, 95% CI -4.87 to -1.23) length of hospital stay compared with traditional perioperative care, without an increase in complications, mortality or readmission rates. CONCLUSION The available evidence based on a broad range of non-randomized studies at high risk of bias suggests that enhanced recovery pathways may reduce length of postoperative hospital stay in abdominal gynecologic surgery.