Burst Strength Analysis of Composite Pressure Vessel using Finite Element Method

Currently, composite pressure vessels are widely utilized in industries like the oil and gas industry and etc. The demand for such vessels is constantly increasing due to their better strength properties than conventional metallic pressure vessels which are heavy and highly prone to corrosion. Thus, this prompts for a more cost effective and sustainable method to assess structural integrity of a composite pressure vessel which could minimize burst failures during operations. However, the main problems are the lack of literatures and research works for design optimization as well as the lack of defined materials for composite pressure vessel construction. Hence, the main objectives of this project are to perform burst failure analysis and to conduct parametric burst failure studies on composite pressure vessels using finite element method. The main scopes of this project are the adaptation of failure criteria like Tsai-Wu, Tsai-Hill and maximum stress in performing burst failure analysis as well as parametric studies on the optimal filament orientation angle and materials used for the liner and shell of a composite pressure vesse

Socioeconomic disparities in rates of facial fracture surgeries for women and men at a regional tertiary care centre in Australia

Background: Assault is the most common mechanism of injury in patients presenting with facial trauma in Australia. For women, there is a propensity for maxillofacial injuries to stem from intimate partner violence (IPV). Those with a low socioeconomic status have higher rates of IPV. This study examines variations in the proportion of surgical procedures that are due to facial trauma for Australian women and men by employment status and residential socioeconomic status. Methods: A single centre retrospective study was conducted (2008–2018). The proportion of operative patients presenting with facial fractures was examined. Multivariable logistic regression adjusting for year and age, was performed for women and men. Results: Facial fractures comprised 1.51% (1602) of all surgeries, patients had a mean age of 32, and 81.3% were male. Unemployed patients were more likely to require surgery for a facial fracture (OR 2.36 (2.09–2.68), P <0.001), and there were no significant variations by index of economic resources (IER). Unemployed males had higher rates of facial fractures (OR 2.09 (1.82–2.39), P <0.001). Unemployed and disadvantaged IER females had higher rates of facial fractures (OR 5.02 (3.73–6.75), P <0.001 and OR 2.31(1.63–3.29), P <0.001). Conclusions: This study found disparities in rates of surgery for facial fractures; unemployment increased the rates for men and women, whereas disadvantaged IER increased rates for women. Studies have demonstrated higher rates of IPV for unemployed and low socioeconomic status women. Further research ascertaining the aetiology of these disparities is important both for primary prevention initiatives and to enable treating clinicians to better understand and address the role of IPV and alcohol consumption in these injuries

Laparoscopic ultralow anterior resection with colonic J-pouch-anal anastomosis

Purpose: Optimal treatment of mid to distal rectal cancers includes total mesorectal excision for oncologic clearance and, where reanastomosis is feasible, a colonic J-pouch-anal anastomosis improves bowel function. There is recent interest in performing an ultralow anterior resection laparoscopically.1-3 A technique is described that includes specimen extraction through the eventual routine defunctioning colostomy or ileostomy site. Methods: Consecutive unselected patients who underwent laparoscopic ultralow anterior resection were recruited. Patients with adenocarcinoma underwent preoperative endorectal ultrasound to individualize for neoadjuvant chemoradiotherapy, based on local extent and lymph nodes seen. The operative procedures were as shown in the video. Posterior dissection along the "total mesorectal excision plane" included incision of Waldeyer's fascia. Bowel continuity was restored by an intracoporeal double-cross stapled colonic J-pouch-anal anastomosis, but where not possible a coloplasty with pull-through handsewn coloanal anastomosis was performed. Results: Laparoscopic ultralow anterior resection was performed on 55 patients (35 men; median age, 63 (range, 33-90) years) from March 2004 to October 2006. The median body mass index was 26.3 (19-38); 14 patients (25 percent) had a body mass index >30. Ten patients (18 percent) had an American Society of Anesthesiologists' classification of III. The indications were adenocarcinoma (n=51), squamous-cell carcinoma of rectum (n=1), dermoid tumor of mesorectum (n=1), large villous adenoma (n=1), and carcinoid with local lymph node metastases (n=1). The adenocarcinomas were a median distance of 6 (3-12) cm from the anal verge. Neoadjuvant radiotherapy was given in 12 patients (24 percent) who had preoperative endoanal ultrasound findings of tumor extension beyond the muscularis propria and chemoradiotherapy in 7 (14 percent) of these patients where the tumor was more bulky and fixed. Laparoscopic ultralow anterior resection was completed at a median 180 (90-405) minutes, with 53.5 (2-2250) ml of blood loss, and the specimen was extracted through a 4.5 (3.5-11) cm wound. The latter included three cases (5 percent) that were converted. Significant adhesiolysis was required in 29 patients (52.7 percent) because of previous operations. The histologic grading or the adenocarcinoma patients were: Stage I, n=14; Stage II, n=23; Stage III, n=11; Stage IV, n=3. Of those who underwent curative resection (Stages I-III), the distal resection margin was 2.9±0.7 cm (mean±standard error) and the radial resection margins were at least 2 mm in all patients. The level of the coloanal anastomosis was a median 3.5 (0-4.5) cm from the anal verge; a coloanal pull-through anastomosis was required in one patient who had a distal cancer. The ileostomies functioned and patients tolerated free fluids at a median of two (1-9) days, and the median postoperative hospital stay was seven (3-22) days. At a median follow-up of 14 (2-33) months, none of the adenocarcinoma patients who had undergone curative resection had recurrences. Four patients (8 percent) had postoperative complications that required operative/invasive intervention (anatomotic leak n=1, proximal bowel ischemia n=1, port site hernia n=1, pelvic collection n=1). Four other patients had smaller pelvic collections that resolved with antibiotics; pelvic collections were associated with advanced stage of cancer (P=0.047). Discharge was delayed by acute gastric distension in 11 patients; the latter was associated with poorer American Society of Anesthesiologists' risk classification (P=0.035). Erectile dysfunction occurred in ten men, and this was associated with adjuvant chemoradiotherapy (P=0.042). One patient (2 percent) had persistent urinary retention that required catheterization at latest follow-up. The ileostomy had been closed in 50 patients, and at last follow-up, the median stool frequency was two (1-8) bowel movements per day. Conclusions: Laparoscopic ultralow anterior resection could be offered routinely and completed safely in Western populations, where obesity and adhesions from previous abdominal surgery is common. A laparoscopic technique readily allowed visual identification of the autonomic nerves in the abdomen over the aorta, which could then be followed down into the pelvis. If the pelvis was deep, inversion of the 30° laparoscope in the "upside down" position fascilited incision of Waldeyer's fascia. This brought the rectum proximally and anteriorly, aiding with the laparoscopic stapler transection of the distal rectum, especially if the cancer was distal, the patient was obese, and the pelvis was narrow. Extraction of the specimen at the eventual defunctioning stoma site reduced the incisions required. Preoperative chemoradiotherapy may have a role in postoperative male sexual dysfunction. Further randomized, controlled studies that include assessing five-year cancer survival/recurrence, pelvic nerve dysfunction, and bowel function are needed before laparoscopic ultralow anterior resection becomes widely accepted

Burst Strength Analysis of Composite Pressure Vessel using Finite Element Method

Currently, composite pressure vessels are widely utilized in industries like the oil and gas industry and etc. The demand for such vessels is constantly increasing due to their better strength properties than conventional metallic pressure vessels which are heavy and highly prone to corrosion. Thus, this prompts for a more cost effective and sustainable method to assess structural integrity of a composite pressure vessel which could minimize burst failures during operations. However, the main problems are the lack of literatures and research works for design optimization as well as the lack of defined materials for composite pressure vessel construction. Hence, the main objectives of this project are to perform burst failure analysis and to conduct parametric burst failure studies on composite pressure vessels using finite element method. The main scopes of this project are the adaptation of failure criteria like Tsai-Wu, Tsai-Hill and maximum stress in performing burst failure analysis as well as parametric studies on the optimal filament orientation angle and materials used for the liner and shell of a composite pressure vesse

Compliance and surgical team perceptions of WHO Surgical Safety Checklist: systematic review

This systematic review aimed to assess surgical safety checklist compliance and evaluate surgical team perceptions and attitudes, post-checklist implementation in the operating room. The World Health Organization (WHO) surgical safety checklist (SSC) has decreased complications and mortality. However, it is unclear whether this reduction is influenced by the vicarious enhancement in teamwork, communication, and staff awareness established by SSC implementation. The preferred reporting items for systematic reviews and meta-analyses model of review guided a search across MEDLINE, PubMed, and Embase databases. English-language studies using any adapted form of the WHO-SSC in operating rooms were reviewed by abstract and full text. Twenty-six studies, 13 assessing SSC compliance and 13 investigating surgical team perceptions of SSC, were evaluated. Compliance studies showed a checklist initiation rate of >90%, but actual observed completion rate varied widely across studies. Sign out was the most poorly performed phase of the checklist (90%) of compliance across studies, but "verification of team-members'' was significantly less compliant. Studies assessing surgical team perceptions found that SSC improved participants' perception of teamwork, communication, patient safety, and staff awareness of adverse events. However, when stakeholders placed differing degrees of importance on SSC completion, results indicated the SSC might actually antagonize team relationships. SSC compliance varies significantly across studies, being highly dependent on staff perceptions, training, and effective leadership. Surgical teams have positive perceptions of SSC; thus with effective implementation strategies, compliance rates across all phases can be substantially improved

Disparities in Advanced Peripheral Arterial Disease Presentation by Socioeconomic Status

Background: Diabetes and peripheral arterial disease (PAD) often synergistically lead to foot ulceration, infection, and gangrene, which may require lower limb amputation. Worldwide there are disparities in the rates of advanced presentation of PAD for vulnerable populations. This study examined rates of advanced presentations of PAD for unemployed patients, those residing in low Index of Economic Resources (IER) areas, and those in rural areas of Australia. Methods: A retrospective study was conducted at a regional tertiary care centre (2008–2018). To capture advanced presentations of PAD, the proportion of operative patients presenting with complications (gangrene/ulcers), the proportion of surgeries that are amputations, and the rate of emergency to elective surgeries were examined. Multivariable logistic regression adjusting for year, age, sex, Charlson Comorbidity Index, and sociodemographic variables was performed. Results: In the period examined, 1115 patients underwent a surgical procedure for PAD. Forty-nine per cent of patients had diabetes. Following multivariable testing, the rates of those requiring amputations were higher for unemployed (OR 1.99(1.05–3.79), p = 0.036) and rural patients (OR 1.83(1.21–2.76), p = 0.004). The rate of presentation with complications was higher for unemployed (OR 7.2(2.13–24.3), p = 0.001), disadvantaged IER (OR 1.91(1.2–3.04), p = 0.007), and rural patients (OR 1.73(1.13–2.65), p = 0.012). The rate of emergency to elective surgery was higher for unemployed (OR 2.32(1.18–4.54), p = 0.015) and rural patients (OR 1.92(1.29–2.86), p = 0.001). Conclusions: This study found disparities in metrics capturing delayed presentations of PAD: higher rates of presentations with complications, higher amputation rates, and increased rates of emergency to elective surgery, for patients of low socioeconomic status and those residing in rural areas. This suggests barriers to appropriate, effective, and timely care exists for these patients

Postoperative adverse events inconsistently improved by the World Health Organization Surgical Safety Checklist: a systematic literature review of 25 studies

Background: The World Health Organization Surgical Safety Checklist (SSC) has been widely implemented in an effort to decrease surgical adverse events. Method: This systematic literature review examined the effects of the SSC on postoperative outcomes. The review included 25 studies: two randomised controlled trials, 13 prospective and ten retrospective cohort trials. A metaanalysis was not conducted as combining observational studies of heterogeneous quality may be highly biased. Results: The quality of the studies was largely suboptimal; only four studies had a concurrent control group, many studies were underpowered to examine specific postoperative outcomes and teamwork-training initiatives were often combined with the implementation of the checklist, confounding the results. The effects of the checklist were largely inconsistent. Postoperative complications were examined in 20 studies; complication rates significantly decreased in ten and increased in one. Eighteen studies examined postoperative mortality. Rates significantly decreased in four and increased in one. Postoperative mortality rates were not significantly decreased in any studies in developed nations, whereas they were significantly decreased in 75 % of studies conducted in developing nations. Conclusions: The checklist may be associated with a decrease in surgical adverse events and this effect seems to be greater in developing nations. With the observed incongruence between specific postoperative outcomes and the overall poor study designs, it is possible that many of the positive changes associated with the use of the checklist were due to temporal changes, confounding factors and publication bias

Postoperative adverse events inconsistently improved by the World Health Organisation Surgical Safety Checklist: a systematic literature review of 25 studies

Background: The World Health Organization Surgical Safety Checklist (SSC) has been widely implemented in an effort to decrease surgical adverse events. Method: This systematic literature review examined the effects of the SSC on postoperative outcomes. The review included 25 studies: two randomised controlled trials, 13 prospective and ten retrospective cohort trials. A metaanalysis was not conducted as combining observational studies of heterogeneous quality may be highly biased. Results: The quality of the studies was largely suboptimal; only four studies had a concurrent control group, many studies were underpowered to examine specific postoperative outcomes and teamwork-training initiatives were often combined with the implementation of the checklist, confounding the results. The effects of the checklist were largely inconsistent. Postoperative complications were examined in 20 studies; complication rates significantly decreased in ten and increased in one. Eighteen studies examined postoperative mortality. Rates significantly decreased in four and increased in one. Postoperative mortality rates were not significantly decreased in any studies in developed nations, whereas they were significantly decreased in 75 % of studies conducted in developing nations. Conclusions: The checklist may be associated with a decrease in surgical adverse events and this effect seems to be greater in developing nations. With the observed incongruence between specific postoperative outcomes and the overall poor study designs, it is possible that many of the positive changes associated with the use of the checklist were due to temporal changes, confounding factors and publication bias

Postoperative adverse events not improved by the World Health Organization Surgical Safety Checklist at a tertiary care centre in Australia

Background: The World Health Organization Surgical Safety Checklist has been widely implemented in an effort to decrease surgical adverse events. The effects of the checklist on postoperative outcomes have not previously been examined in Australia. Methods: A retrospective review was conducted using administrative data over a 5-year time period to examine the effects of the implementation of the checklist on rates of postoperative outcomes in a sample of 6,028 surgical procedures at a tertiary care centre in Australia. Results: The adjusted total complication, postoperative mortality and readmission to hospital rates did not significantly change between pre and post implementation [9.4% to 10.4% (p=0.43, OR 1.1 (0.89-1.3)), 0.93% to 0.85% (p=0.70, OR 0.90 (0.51-1.6)), 4.5% to 5.0% (p=0.36, OR 1.1 (0.89-1.3))]. The findings remained insignificant when a sub analysis was conducted on high risk surgical groups; emergency cases and surgical procedures in the elderly. The data was separated into 6-month time periods for a nalysis of operative complication and mortality rates over time; these were consistent (mean 10% SD 1.06, mean 0.9% SD 0.31, respectively). Conclusion: Implementation of the WHO SSC was not associated with a statistically significant reduction in any operative outcomes examined over a 5-year time period in a regional tertiary care centre in Australia. This may be due to the checklist having a reduced effect in developed countries or due to the mandatory implementation of the checklist; leading to a tick and flick mentality surrounding its use. Further research is required to support the ongoing checklist use in Australia

A meta-analysis of the prevalence of low anterior resection syndrome and systemic review of risk factors

Background: With the increasing use of low anterior resection (LAR) to treat rectal cancer and avoid a permanent stoma, there has been increasing recognition of mid/long term post-operative persisting altered bowel function known as Low Anterior Resection Syndrome (LARS). The aim of this review is to estimate the prevalence of LARS, using studies which utilise the LARS score as their data collection tool. Factors implicated in the causation of the syndrome will also be investigated as it will together allow for better informed consent for patients undergoing treatment. Methods: A systematic literature search was conducted using Pubmed, Ovid Medline and the Cochrane database. Searches were performed using a combination of MeSH (medical subject headings) terms and key terms. Results: The estimated prevalence of major LARS ranged from 17.8% - 56%, with a mean of 31.5%. The patient population who has undergone a LAR is heterogenous with much variability due to tumour, patient and treatment characteristics. Radiotherapy and tumour height were the most consistently assessed variables and reached statistical significance in 8 and 7 of the studies respectively, both showing a consistent negative effect on bowel function. Defunctioning ileostomy was found to have a statistically significant negative impact on bowel function in 4 studies. Conclusions: There is likely a significant prevalence of mid-term persisting LARS after LAR. Larger studies that have greater patient numbers and more robust study design suggest that overall prevalence is between 40-52%. Radiotherapy, whether pre or post-operative, and low tumour height are the 2 factors which have the greatest negative impact of patients bowel function following LAR