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The following represent additions to UpToDate from the past six months that were considered by the editors and authors to be of particular interest. The most recent What's New entries are at the top of each subsection.
ANESTHESIA AND PERIOPERATIVE CARE
Safety of magnetic resonance imaging and gadolinium in pregnancy (September 2016)
Magnetic resonance imaging (MRI) may be used for diagnostic imaging in pregnancy when ultrasound examination is inadequate; however, fetal safety has not been conclusively established. Recently, the largest study of MRI in pregnancy (over 1700 exposed and 1.4 million unexposed births) reported that first-trimester MRI was not associated with significantly increased risks for stillbirth, neonatal death, congenital anomaly, neoplasm, or vision or hearing loss in children followed up to age four years, when adjustments were made for differences between exposure groups . The study also found that gadolinium exposure at any time during pregnancy was associated with an increased risk for stillbirth and neonatal death. Children exposed in utero were at increased risk for rheumatological, inflammatory, or infiltrative skin conditions, but not congenital anomalies or nephrogenic systemic fibrosis (NSF). This study is a major addition to the body of evidence supporting the safety of MRI in pregnancy when medically indicated. It also provides the first data supporting existing recommendations to avoid use of gadolinium-based contrast agents in pregnant women, when possible. (See "Diagnostic imaging procedures during pregnancy", section on 'Magnetic resonance imaging'.)
Aspirin does not prevent acute respiratory distress syndrome in adults (July 2016)
Preclinical and clinical observational studies have suggested a potential role for aspirin in the prevention of acute respiratory distress syndrome (ARDS). The ability of aspirin to prevent ARDS was tested in a randomized trial of 390 patients who were assessed upon presentation to an emergency department to be at risk of developing ARDS . Aspirin, administered at 325 mg orally followed by 81 mg daily for seven days, had no effect on the incidence of ARDS at one week (approximately 10 percent in each group). However, the lower than expected rate of ARDS in this study may have limited the potential to detect a study drug effect. (See "Acute respiratory distress syndrome: Novel therapies in adults", section on 'Aspirin'.)
Dosing of direct oral anticoagulants in obese patients (June 2016)
Limited data are available to guide dosing of direct oral anticoagulants (DOACs; dabigatran, apixaban, edoxaban, rivaroxaban) in patients with obesity. The International Society of Thrombosis and Hemostasis (ISTH) has issued guidance on this subject . The major recommendations include use of DOACs at standard doses for those with a body mass index (BMI) ≤40 kg/m2 or weight <120 kg, and avoidance of DOACs in individuals with a BMI >40 kg/m2 or weight ≥120 kg. (See "Direct oral anticoagulants: Dosing and adverse effects".)
Showering after uncomplicated surgery (April 2016)
When a patient can resume bathing/showering after uncomplicated surgery is not well defined. A recent trial randomly assigned 444 patients undergoing procedures classified as clean or clean-contaminated to showering with the wound undressed 48 hours after surgery or no showering until stitches were removed (median time 10 days) . The rate of surgical site infection was not significantly different between the groups, suggesting that showering is safe following an initial period of wound coverage (48 hours). (See "Basic principles of wound management", section on 'Acute wounds'.)
ARTERIAL AND VENOUS ACCESS
Locking solutions for preventing hemodialysis catheter malfunction (July 2016)
Heparin is commonly used as a locking solution to prevent hemodialysis catheter malfunction. Alternative locking solutions (eg, citrate, recombinant tissue plasminogen activator, various antimicrobial agents) and systemic anticoagulation (eg, warfarin) have also been tried. In a recent metaanalysis of randomized trials of alternative agents for preventing central venous hemodialysis catheter malfunction, the incidence of malfunction was not significantly different with use of alternative locking solutions or systemic agents compared with usual care, which was typically instillation of heparin 5000 units into each catheter port . The results of this systematic review confirm our practice of using heparin to minimize catheter malfunction, given its ease of use, availability, and relatively low cost compared with alternative agents. (See "Central catheters for acute and chronic hemodialysis access", section on 'Anticoagulant locking solutions'.)
Closure of mesenteric defects during laparoscopic gastric bypass (April 2016)
Laparoscopic gastric bypass is one of the most commonly performed bariatric procedures; however, mesenteric defects created during the procedure are a major cause of small bowel obstruction. In a randomized trial including over 2500 laparoscopic gastric bypass procedures with or without mesenteric defect closure, mesenteric closure reduced the incidence of reoperation for small bowel obstruction at three years (6 versus 10 percent), but increased the incidence of early severe postoperative complications (4.3 versus 2.8 percent), which were primarily due to kinking of the small bowel anastomosis . We advocate routine closure of all mesenteric defects during gastric bypass to reduce the overall risk of small bowel obstruction. Future refinements in the technique of small bowel anastomosis may reduce the risk of early postoperative complications. (See "Late complications of bariatric surgical operations", section on 'Internal hernias'.)
Hemorrhoidal artery ligation not superior to rubber band ligation for internal hemorrhoids (August 2016)
Doppler-guided transanal hemorrhoidal artery ligation (HAL) is a relatively new procedure that uses Doppler ultrasound to identify and ligate the hemorrhoidal arterial blood supply. In a recent trial of 337 patients with grade II or III internal hemorrhoids randomly assigned to treatment with HAL or rubber band ligation (RBL), HAL resulted in greater pain, more serious adverse events requiring hospitalization, and higher costs, but fewer recurrences within 12 months of the procedure . However, the additional recurrences in the RBL group were largely attributable to repeated procedures in patients with multiple hemorrhoids. Repeat RBL is common in this group since typically only one hemorrhoid column is banded at each RBL session. Given its low morbidity and cost, RBL remains the first-line treatment for symptomatic internal hemorrhoids. (See "Surgical treatment of hemorrhoidal disease", section on 'Hemorrhoidal artery ligation'.)
HEPATOBILIARY AND PANCREATIC SURGERY
Adverse outcomes with lack of follow-up following emergency department visit for biliary colic (April 2016)
Proper follow-up of patients being discharged from the emergency department following an episode of symptomatic gallstones is important to avoid adverse outcomes. This was examined in a study of more than 11,000 Texas Medicare patients age 66 and older with symptomatic gallstones who were discharged from the emergency department without undergoing cholecystectomy . A quarter of the patients did not see a physician in follow-up. Subsequent emergency hospitalization was required in 78 percent of those patients (compared with 8 percent of those who saw a surgeon and 15 percent of those who saw a physician other than a surgeon). Of the patients with biliary colic, 17 percent required emergency cholecystectomy, with a complication rate of 41 percent (compared with a 19 percent complication rate for elective cholecystectomy). This study reinforces the importance of appropriate follow-up and management for patients with symptomatic gallstones. (See "Uncomplicated gallstone disease in adults", section on 'Cholecystectomy'.)
Perioperative complications in minimally invasive live donor nephrectomy (September 2016)
Minimally invasive donor nephrectomies account for more than half of live donor nephrectomies performed for kidney transplantation. A systematic review of over 32,000 minimally invasive live donor nephrectomies demonstrated a low operative mortality rate of 0.01 percent and low rates of intraoperative and postoperative complications (primarily bleeding and infections) . Comparison of the different minimally invasive techniques found similar complication rates between hand-assisted versus non-hand-assisted, laparoscopic versus retroperitoneoscopic, and multiport versus single-port procedures. (See "Benefits and complications of minimally invasive live-donor nephrectomy", section on 'Donor morbidity'.)
TRAUMA AND BURN SURGERY
Oxandrolone to treat moderate-to-severe burns (August 2016)
Many pharmacological therapies have been tried to reverse the damaging effects of the hypermetabolic response to severe injury. Trials evaluating anabolic steroids, which improve protein balance, have reported inconsistent outcomes. A recent systematic review included 15 randomized trials of adults and children with severe burns (>20 percent total body surface area) treated with oxandrolone, a testosterone analog, versus placebo or blank controls . Meta-analyses of individual outcome measures in the acute phase, intermediate phase, and long term showed significant improvements in metabolic parameters (eg, less nitrogen loss, less weight loss, increased lean body mass, improved wound healing), shortened length of stay, and no significant differences in adverse events (mortality, infection, liver dysfunction). These results support our recommendation to treat all patients with moderate-to-severe burns with oxandrolone (10 mg twice daily in adults; 5 mg twice daily in children and patients >65 years of age). (See "Hypermetabolic response to severe burn injury: Recognition and treatment", section on 'Oxandrolone'.)
New guidelines for the management of Stevens-Johnson/toxic epidermal necrolysis syndrome (August 2016)
The British Association of Dermatologists released new guidelines for the management of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), a severe and potentially fatal mucocutaneous drug reaction . The guidelines provide evidence-based recommendations for the diagnosis, severity assessment, and management of SJS/TEN. Specific areas covered include initial management, supportive care, and therapies intended to reduce mortality, such as intravenous immune globulins, systemic corticosteroids, and cyclosporine. The treatment of eye involvement, including systemic therapies and amniotic membrane transplantation to prevent permanent ocular sequelae, as well as the management of oral, urogenital, and airway mucosal involvement are also addressed. (See "Stevens-Johnson syndrome and toxic epidermal necrolysis: Management, prognosis, and long-term sequelae", section on 'General principles'.)
Thromboelastography-guided transfusion in trauma patients (July 2016)
Coagulopathy associated with trauma is evident in 25 to 35 percent of severely injured civilian patients and is associated with increased morbidity and mortality. Thromboelastography (TEG) is a point-of-care testing method that rapidly provides information on the properties of clot formation, detects hyperfibrinolysis, and may offer an advantage over standard coagulation assays. The results of a randomized trial are consistent with observations suggesting that TEG-parameter-guided resuscitation may improve outcomes . Following initial transfusion triggered by activation of a massive transfusion protocol, 111 injured patients were randomly assigned to subsequent transfusions based upon TEG parameters or conventional coagulation assays. Mortality rates were significantly lower for the TEG group compared with the conventional group at 6 hours and 28 days (7.1 versus 21.8 percent, and 19.6 versus 36.4 percent, respectively). Although there were no differences in the overall volume of transfusion at 24 hours, the standard assay group received more plasma and platelets during the first several hours of resuscitation. Where TEG is available, we suggest TEG-based goal-directed resuscitation for trauma patients requiring massive transfusion. (See "Coagulopathy associated with trauma", section on 'Thromboelastography-based transfusion'.)
Immunocompetence following splenic embolization for trauma (April 2016)
Routine immunization is recommended following splenectomy, but the need for immunization following nonsurgical treatment of splenic injury is unclear. In a systematic review of 12 observational studies of splenic function after angioembolization for splenic trauma, most studies found that splenic function was preserved . However, uncertainty remains since the studies used different parameters to assess splenic function and the best parameter/test to assess immunocompetence in this population has not been determined. Overall, these studies support our practice of not immunizing patients following splenic embolization, splenic salvage surgery, or nonoperative management. (See "Management of splenic injury in the adult trauma patient", section on 'Immunocompetence after splenic injury'.)
UPPER GASTROINTESTINAL SURGERY
Laparoscopic versus open surgery for advanced gastric cancer (May 2016)
Open gastrectomy is the standard surgical treatment for gastric cancer worldwide; however, laparoscopic gastrectomy is performed with increasing frequency for early gastric cancers in high-volume centers with the requisite expertise, mainly in Asia. A recent randomized trial conducted in China compared the safety and efficacy of laparoscopic versus open resection in 1056 patients with advanced gastric cancers (T2-4a, N0-3, M0) . Rates of postoperative mortality and morbidity, severe morbidity, and completion of a D2 lymphadenectomy were similar in both groups; follow-up has been inadequate for meaningful assessment of oncologic outcomes. Western populations, however, may have different outcomes since surgeon experience and patient characteristics are different. Patients in Western countries are generally older, more obese, and more likely to have poorly differentiated tumors than Asian populations, which could impact successful use of laparoscopic surgery. Further trials in Western countries are required before laparoscopic surgery can be recommended for the routine treatment of all gastric cancers. (See "Surgical management of invasive gastric cancer", section on 'Open versus laparoscopic resection'.)
VASCULAR AND ENDOVASCULAR SURGERY
Bioresorbable drug-eluting iliac artery stenting for PAD (July 2016)
Metal stents are commonly used to treat suboptimal transluminal angioplasty, but restenosis remains a problem. Bioresorbable scaffolds have been used in the coronary circulation, but may increase stent thrombosis. A recent feasibility study reported the first clinical use of a drug-eluting (everolimus) bioresorbable vascular scaffold to treat 66 patients with symptomatic peripheral artery disease in the iliac or femoral arteries . At one and two years follow-up, binary restenosis rates (>50 percent) were 12.1 and 16.1 percent, respectively, and freedom from target lesion revascularization was 91.2 and 88.2 percent, respectively. There were no procedure-related amputations or deaths at two years follow-up. Although these results are encouraging, direct comparisons with drug-eluting balloons and drug-eluting polymer-coated metal stents are needed. (See "Percutaneous interventional procedures in the patient with lower extremity claudication", section on 'Aortoiliac occlusive disease'.)
Ticagrelor in patients with peripheral artery disease (July 2016)
Patients with a history of myocardial infarction and concomitant lower extremity peripheral artery disease (PAD) are at increased risk for both systemic and limb ischemic events. Long-term antiplatelet therapy with aspirin is recommended for these patients. Whether adding a second agent offers additional benefits in this population is unclear. A recent large multicenter trial randomly assigned over 21,000 patients with prior myocardial infarction (MI) to ticagrelor 90 mg twice daily, ticagrelor 60 mg twice daily, or placebo in addition to low-dose aspirin . Among the subset of patients with previously identified PAD (n = 1143), compared with placebo, use of ticagrelor reduced the absolute rate of major adverse cardiovascular events (MACE) by 4.1 percent and reduced the risk for peripheral revascularization for limb ischemia (hazard ratio [HR] 0.63; 95% CI 0.43-0.93), with a 0.12 percent absolute excess of major bleeding. Given methodologic issues with data ascertainment, further trials are needed to determine if the benefits of dual therapy outweigh the bleeding risk. We do not use dual antiplatelet therapy in patients with PAD in the absence of other indications (eg, drug-eluting stent). (See "Overview of lower extremity peripheral artery disease", section on 'Antithrombotic therapy'.)
Genetically determined clopidogrel nonresponsiveness and DAPT outcomes (June 2016)
Dual antiplatelet therapy (DAPT), compared with aspirin alone, lowers the risk of subsequent ischemic events in patients with established atherosclerotic cardiovascular disease. However, many patients on DAPT experience ischemic events. One potential cause of treatment failure is failure to properly metabolize clopidogrel; the presence of the CYP2C19 loss of function allele has been correlated with clopidogrel resistance. The CHANCE trial of patients with transient ischemic attack or minor stroke found that DAPT was more effective in preventing subsequent stroke than aspirin alone. A 2016 subgroup analysis of 2933 individuals in CHANCE, who had genotyping for CYP2C19 genetic variants performed, found that the risk of stroke was lower among noncarriers of the CYP2C19 loss of function allele than those who carried the allele . While the evidence seems to be increasing that genetic variation may determine outcome with the use of clopidogrel, we do not recommend genotyping for clopidogrel loss of function genetic variants or testing for clopidogrel hypo/nonresponsiveness. (See "Clopidogrel resistance and clopidogrel treatment failure", section on 'Loss of function gene carriers'.)
OTHER GENERAL SURGERY
Thymectomy for myasthenia gravis (August 2016)
Lacking evidence from randomized trials, thymectomy for patients with nonthymomatous myasthenia gravis (MG) had been controversial. Now, the benefit of thymectomy is supported by the results of the multicenter, assessor-blinded MGTX trial, which enrolled 126 subjects with generalized acetylcholine receptor (AChR) antibody-associated MG and randomly assigned them to thymectomy plus alternate-day prednisone or alternate-day prednisone alone . Over a three-year period, thymectomy improved multiple clinical outcomes, including quantitative strength testing, average alternating-day prednisone requirements (44 versus 60 mg), need for azathioprine immunosuppression (17 versus 48 percent), and hospitalization for acute exacerbations (9 versus 37 percent). Based on these results and prior observational data, we recommend thymectomy for patients age <60 years with nonthymomatous, generalized acetylcholine receptor (AChR) antibody-associated MG. Thymectomy is also indicated in all patients with thymoma if resection is feasible. (See "Thymectomy for myasthenia gravis", section on 'Efficacy'.)
Routine chest tube suction unnecessary following nonpneumonectomy lung resection (April 2016)
Whether ongoing suction to the chest tube improves or worsens pleural leaks following elective lung resection (not lung reduction surgery or pneumonectomy) is controversial. In a meta-analysis of randomized trials of suction versus no suction on chest drains following lung resection, suction did not affect the occurrence of prolonged air leak . Based on the lack of benefit and disadvantages associated with ongoing suction, we suggest not routinely using ongoing chest tube suction following elective lung resection (not lung reduction surgery or pneumonectomy). However, for patients with postoperative pneumothorax, worsening pneumothorax on follow-up postoperative chest radiographs, or increasing subcutaneous air on physical exam, the chest tube should be connected to suction. (See "Placement and management of thoracostomy tubes", section on 'Level of suction'.)
Bariatric surgery benefits joint pain and physical function (April 2016)
Morbid obesity is associated with significant joint pain and limitations in physical activities. Bariatric surgery is effective in promoting weight loss, which may ameliorate these problems. In one study of over 2000 patients undergoing bariatric surgery for severe obesity, 50 to 75 percent reported significant improvements in body, hip, and knee pain, and physical functions at one year after surgery . Improvements in knee and hip pain were sustained at three years. This study demonstrates that bariatric surgery can improve patient outcomes that are beyond the metabolic syndrome. (See "Medical outcomes following bariatric surgery", section on 'Pain and physical function'.)
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