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Introduction: Hyperbaric chamber ventilation (HCV) refers to the intentional introduction of fresh gas, whether air, oxygen, or heliox, into a pressurised hyperbaric chamber in order to remove stale or otherwise compromised gas. The minimum required continuous HCV rate is usually determined by mathematical models derived from the contaminant mass balance within a well-stirred compartment. Non-uniform contaminant distribution patterns inside a hyperbaric chamber could emerge and invalidate the predictions of well-stirred models. Methods: Contaminant distribution was investigated inside a clinical hyperbaric chamber with the aim of comparing wellstirred model predictions with the actual contaminant concentration measurements. Results: Local ventilation effectiveness inside a clinical hyperbaric chamber may be compromised, leading to higher contaminant concentration values compared to the predictions of a mathematical model with a well-stirred assumption. Conclusions: A well-stirred assumption in mathematical models is a useful simplification that allows reasonably accurate estimates of HCV requirements. However, local ventilation effectiveness values in a particular hyperbaric chamber might vary, with the potential for hazardous contaminant accumulation in under-ventilated zones. [ABSTRACT FROM AUTHOR]

Introduction: Scuba diving is a big part of the tourism sector in Malta, and all the cases of decompression illness (DCI) are treated within the single hyperbaric referral centre in the country. Methods: This retrospective analysis reviews all the medical records of divers with DCI in Malta within the 30-year period between 1987 to 2017 who required recompression therapy with hyperbaric oxygen. Results: There were 437 discrete cases of DCI managed with recompression therapy. Amongst DCI subtypes, the prevalence of musculo-skeletal DCI is decreasing, whereas that of vestibulo-cochlear DCI is increasing. Conclusion: The increasing prevalence of vestibulo-cochlear DCI may be due to a change in diving practices in Malta. [ABSTRACT FROM AUTHOR]

Background For patients with poor weight loss (WL) after Roux-en-Y gastric bypass (RYGB) there are few well-tolerated and effective surgical options. Revision to distal bypass by shortening of the common channel (CC) induces significant WL but often produces protein calorie malnutrition (PCM) and severe diarrhea. Objective The aim of this study was to identify a safe and effective threshold for distal small bowel bypass when done for revision of gastric bypass. Setting Academic Institution, United States. Methods We performed revision of RYGB for WL in 20 patients by shortening the CC to a new length of 120–300 cm. The Roux limb length was unchanged. WL and PCM were monitored. A threshold for percent of small bowel bypassed at which PCM was avoided was retrospectively determined. WL was then compared in patients above and below this threshold. Five patients completed a 250-kcal mixed meal challenge before and 3 months after revision to determine selected gut hormone responses. Results Bypassing≥70% small bowel resulted in PCM in 4 of 10 patients but in none of 10 patients below that threshold. PCM was observed as late as 2 years after revision and necessitated rerevision by lengthening of the CC in 3 patients. Additionally, nocturnal diarrhea was more common and more intractable when≥70% bypass was done. Both groups had significant excess body WL over 2 years, but it was greater in patients with≥70% bypass (47±19 versus 26±17; P <.05). A favorable gut hormone response was observed with 3-hour decrease in glucose-dependent insulinotropic peptide (GIP) by 25% and increase in glucagon-like peptide-1 (GLP-1) by 25%, whereas fasting peptide-YY (PYY) increased by 71% ( P <.05 for all). Conclusions Revision of RYGB to distal bypass when it is<70% of a patient’s small bowel length results in an acceptable balance of WL and a positive safety profile. WL may be mediated through an enhanced gut hormone effect, an aversion to ingested fat, and possibly other mechanisms. [ABSTRACT FROM AUTHOR]

Background: Roux-en-Y gastric bypass (RYGB) results in profound weight loss and resolution of type 2 diabetes mellitus (T2DM). The mechanism of this remarkable transition remains poorly defined. It has been proposed that endotoxin (lipopolysaccharide [LPS]) sets inflammatory tone, triggers weight gain, and initiates T2DM. Because RYGB may diminish LPS from endogenous and exogenous sources, we hypothesized that LPS and the associated cascade of oxidative and inflammatory stress would diminish after RYGB. Methods: Fifteen adults with morbid obesity and T2DM undergoing RYGB were studied. After an overnight fast, a baseline blood sample was collected the morning of surgery and at 180 days to assess changes in glycemia, insulin resistance, LPS, mononuclear cell nuclear factor (NF)-κB binding and mRNA expression of CD14, TLR-2, TLR-4, and markers of inflammatory stress. Results: At 180 days after RYGB, subjects had a significant decrease in body mass index (52.1 ± 13.0 to 40.4 ± 11.1), plasma glucose (148 ± 8 to 101 ± 4 mg/dL), insulin (18.5 ± 2.2 mμU/mL to 8.6 ± 1.0 mμU/mL) and HOMA-IR (7.1 ± 1.1 to 2.1 ± 0.3). Plasma LPS significantly reduced by 20 ± 5% (0.567 ± 0.033 U/mL to 0.443 ± 0.022E U/mL). NF-κB DNA binding decreased significantly by 21 ± 8%, whereas TLR-4, TLR-2, and CD-14 expression decreased significantly by 25 ± 9%, 42 ± 8%, and 27 ± 10%, respectively. Inflammatory mediators CRP, MMP-9, and MCP-1 decreased significantly by 47 ± 7% (10.7 ± 1.6 mg/L to 5.8 ± 1.0 mg/L), 15 ± 6% (492 ± 42 ng/mL to 356 ± 26 ng/mL) and 11 ± 4% (522 ± 35 ng/mL to 466 ± 35 ng/mL), respectively. Conclusion: LPS, NF-κB DNA binding, TLR-4, TLR-2, and CD14 expression, CRP, MMP-9, and MCP-1 decreased significantly after RYGB. The mechanism underlying resolution of insulin resistance and T2DM after RYGB may be attributable, at least in part, to the reduction of endotoxemia and associated proinflammatory mediators. [ABSTRACT FROM AUTHOR]

Background: Pulmonary embolism (PE) is a leading cause of death after roux-en-Y gastric bypass (RYGB); therefore, current recommendations for prophylaxis may be inadequate. Methods: We reviewed our first 1,341 patients (controls) who underwent RYGB and weighted factors that may have contributed to PE to arrive at a pulmonary embolism risk score (PERS). We postulated that more aggressive prophylaxis in higher risk patients might have reduced the incidence of PE. We tested our hypothesis by basing prophylaxis on the PERS in 1,652 subsequent RYGB patients (study group). Standard risk patients (PERS <4) were ambulated 2 hours after surgery, had application of intermittent compression devices, and received subcutaneous low-dose, unfractionated heparin (LDUH). Intermediate risk patients (PERS = 4) received standard prophylaxis and 3 weeks of postdischarge LDUH. High-risk patients (PERS >4) had postdischarge LDUH and a preoperative vena cava filter. Results: The 0.36% incidence of PE (6 patients) in the study group was significantly lower (P <.05) than the 1% incidence (13 patients) in the controls. Three of 189 men in the control group died of PE, whereas there were no deaths from PE in 271 men in the study group (P <.05). Conclusion: The PERS may be an appropriate scoring system for determining preoperatively the level of risk for postoperative PE in RYGB patients. Basing prophylaxis on the level of risk reduces the incidence and mortality of PE and consumes resources judiciously. [Copyright &y& Elsevier]

Abstract: Background: The Internet is a valuable method of information sharing and could have important applications for bariatric surgical practices. The purpose of this study was to devise criteria by which Centers of Excellence Web sites could be evaluated. By applying these criteria to the study sample, we hoped to identify specific content that could improve Web site functionality and, thereby, its efficacy. Methods: We developed an original survey instrument that used specific criteria of Web site content to determine its functionality. The categories of content were Marketing, Interactivity, Education, and Support. Each of these categories was further divided into 3–7 subcategories for more in-depth analysis. From the Surgical Review Committee Web site page, 66 Centers of Excellence Web sites met our inclusion criteria of private, exclusively bariatric surgery practices. We then applied the survey instrument to evaluate their functionality. Results: The survey revealed marketing and education content in all sites, and nearly all were interactive and provided patient support. However, all Web sites had deficiencies in >1 subcategory. Conclusion: Many Centers of Excellence have a Web presence. However, the opportunity exists to increase Web site functionality and efficacy by improving content in specific areas and using up-to-date technology. [Copyright &y& Elsevier]

Abstract: Background: Because rapid weight loss after bariatric surgery increases gallstone formation, a 6-month treatment regimen with ursodiol has been recommended. Even prophylactic cholecystectomy at the time of gastric bypass in the absence of stones has been proposed. However, the incidence of symptomatic gallstones requiring cholecystectomy in untreated patients after gastric bypass has not yet been established. Methods: The patients in our study were not treated with ursodiol after open Roux-en-Y gastric bypass. Additional inclusion criteria were no palpable gallstones at bypass, at least 16 months of follow-up after bypass, and continuous coverage by the same health insurance plan extending from the time of the operation to study completion, to track subsequent cholecystectomies by claims paid. Results: A total of 100 females and 25 males met the study inclusion criteria. Follow-up extended from 16 to 48 months. Symptomatic gallstones requiring cholecystectomy developed in 10 patients, all females. Laparoscopic cholecystectomy was performed in 9 of these patients and open cholecystectomy was performed in the remaining patient, between 3 and 21 months after bypass. There were no serious complications from the stones or the cholecystectomy. Conclusions: Prophylactic cholecystectomy would have been unnecessary in 115 of the 125 patients in the study group. A 6-month course of ursodiol for all 125 patients, at a cost of $56,250, would have had to decrease the number of cholecystectomies from 10 to 3 to demonstrate a treatment effect (P < .05). Therefore, most newly formed gallstones after gastric bypass are likely asymptomatic, prophylactic cholecystectomy is not indicated, and ursodiol therapy may be better reserved for symptomatic patients who refuse surgery. © 2005 American Society for Bariatric Surgery [Copyright &y& Elsevier]

Abstract: Background: The antiplatelet drug clopidogrel (Plavix) is widely used in patients who have undergone coronary artery stenting or had a stroke. Because morbid obesity is associated with atherosclerosis, some of these patients are candidates for weight loss surgery. We chose to determine the risk of upper gastrointestinal bleeding after gastric bypass in patients taking clopidogrel. Methods: Patients who took clopidogrel after gastric bypass were identified by specific review of the subset of patients who had had upper gastrointestinal bleeding requiring hospital admission and transfusion. All who bled underwent emergency endoscopy. Results: Of 11 patients taking clopidogrel, 4 (36%) presented with significant upper gastrointestinal bleeding 25–234 days after gastric bypass. All stopped bleeding with discontinuation of the drug and treatment with an intravenous proton pump inhibitor. Conclusion: Gastric bypass patients appear to be at high risk of bleeding complications when taking clopidogrel. On the basis of the available published data from another high-risk group (i.e., those with a history of peptic ulcer disease), co-treatment with omeprazole may be indicated when clopidogrel must be continued. [Copyright &y& Elsevier]