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Dive into the research topics where Oliver Warren is active.

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Featured researches published by Oliver Warren.


Journal of Clinical Investigation | 2007

Better: A surgeon’s notes on performance

Ara Darzi; Oliver Warren

In Better: a surgeon’s notes on performance, Atul Gawande, best-selling author of Complications: a surgeon’s notes on an imperfect science, general and endocrine surgeon at Brigham and Women’s Hospital, and assistant professor at Harvard Medical School and Harvard School of Public Health, investigates human performance in medicine. He takes the reader to courtrooms, clinics, war zones, and execution chambers to demonstrate the incredible environments in which doctors care for and treat patients. While drawing on a vast array of sources, including his own personal experience, Gawande interweaves into nearly every chapter fascinating vignettes about the most important person in his view of medicine: the patient. By ensuring that every message is personalized in this manner, he brings a warm, humane touch to this superb book.


World Journal of Emergency Surgery | 2006

Emergency laparoscopy--current best practice.

Oliver Warren; James Kinross; Paraskevas Paraskeva; Ara Darzi

Emergency laparoscopic surgery allows both the evaluation of acute abdominal pain and the treatment of many common acute abdominal disorders. This review critically evaluates the current evidence base for the use of laparoscopy, both diagnostic and interventional, in the emergency abdomen, and provides guidance for surgeons as to current best practise. Laparoscopic surgery is firmly established as the best intervention in acute appendicitis, acute cholecystitis and most gynaecological emergencies but requires further randomised controlled trials to definitively establish its role in other conditions.


Biomarkers in Medicine | 2009

Intestinal ischemia/reperfusion injury: defining the role of the gut microbiome

James Kinross; Oliver Warren; Sonia Basson; Elaine Holmes; David B. Silk; Ara Darzi; Jeremy K. Nicholson

Intestinal ischemia/reperfusion (I/R) injury initiates a systemic inflammatory response syndrome with a high associated mortality rate. Early diagnosis is essential for reducing surgical mortality, yet current clinical biomarkers are insufficient. Metabonomics is a novel strategy for studying intestinal I/R, which may be used as part of a systems approach for quantitatively analyzing the intestinal microbiome during gut injury. By deconvolving the mammalian-microbial symbiotic relationship systems biology thus has the potential for personalized risk stratification in patients exposed to intestinal I/R. This review describes the mechanism of intestinal I/R and explores the essential role of the intestinal microbiota in the initiation of systemic inflammatory response syndrome. Furthermore, it analyzes current and future approaches for elucidating the mechanism of this condition.


World Journal of Surgery | 2008

New Technologies for the Surgical Curriculum

Rajesh Aggarwal; Julian Leong; Daniel Leff; Oliver Warren; Guang-Zhong Yang; Ara Darzi

The aim of a surgical residency program is to produce competent professionals displaying the cognitive, technical, and personal skills required to meet the needs of society. Current changes to the delivery of healthcare necessitate the development of new models of training. These can be supported with the development of new technologies to train and assess surgical practitioners. This article describes recent developments within Imperial College London with regard to eye tracking, noninvasive brain imaging, and an innovative mentoring scheme for the new surgical curriculum. The concept of eye tracking is described, together with surgical application for this technique in terms of dexterity analysis during minimally invasive procedures. We have also begun to understand spatial localization within the brain cortex during surgical knot-tying tasks. The aim is to develop a map of the cortex with regard to surgical novices and experienced surgeons and then to develop the hypothesis that a translational process of cortical plasticity occurs during training. Finally, the article is intended to describe a training scheme that goes beyond dexterity, and moves toward the development of a successful surgeon through surgical mentoring. It is hoped that some of these tools will enhance the training of future surgeons in order to continue to provide a high-quality service to our patients.


Asaio Journal | 2007

Does systemic leukocyte filtration affect perioperative hemorrhage in cardiac surgery: a systematic review and meta-analysis

Oliver Warren; Sophie Wallace; Rachel Massey; Caroline Tunnicliffe; Christos Alexiou; John Powell; Narendra Meisuria; Ara Darzi; Thanos Athanasiou

Cardiopulmonary bypass causes a systemic inflammatory reaction. Activation of leukocytes is an important part of this process, and is known to directly contribute to the development of postoperative coagulopathy, and thus hemorrhage. The removal of leukocytes from the cardiopulmonary bypass circulation, using specialized filters, has been proposed as one method for attenuating this inflammatory response. However, there is no consensus on its effectiveness. We used meta-analytical techniques to systematically assess the literature reporting on the potential effect of systemic leukofiltration on perioperative hemorrhage. Random effects modeling was used to calculate overall estimate, and heterogeneity was assessed. Systemic leukofiltration made no significant impact on chest tube drainage in the first 24 hours (weighted mean difference [WMD], ×23.9 ml; 95% confidence interval [CI], ×95.48–47.61; p = 0.51) or on the total packed red cell transfusion requirements of each patient (WMD, 7.84 ml; 95% CI, ×80.13–95.81; p = 0.86). The studies performed in this area thus far are highly heterogeneous, due in part to relatively poor-quality design and inadequate matching of their study groups. Although further high-quality trials on systemic leukofiltration may be appropriate, other strategies to reduce the coagulopathy associated with cardiopulmonary bypass should be sought and evaluated.


Journal of Physics A | 2007

Genus two finite gap solutions to the vector nonlinear Schrödinger equation

Thomas Woodcock; Oliver Warren; John N. Elgin

A recently published article presents a technique used to derive explicit formulae for odd genus solutions to the vector nonlinear Schrodinger equation. In another article solutions of genus two are derived using a different approach which assumes a separable ansatz. In this communication, the extension of the first technique to the even genus case is discussed, and this extension is carried out explicitly for genus two. Furthermore, a birational mapping is found between the spectral curves that arise in the two approaches.


Diseases of The Colon & Rectum | 2018

Comparison of Western and Asian Guidelines Concerning the Management of Colon Cancer

Gianluca Pellino; Oliver Warren; Sarah Mills; Shahnawaz Rasheed; Paris P. Tekkis; Christos Kontovounisios

BACKGROUND: Guidelines are important to standardize treatments and optimize outcomes. Several societies have published authoritative guidelines for patients with colon cancer, and a certain degree of variation can be predicted. OBJECTIVE: This study aims to compare Western and Asian guidelines for the management of colon cancer. DATA SOURCES: A literature review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for studies published between 2010 and 2017 by the online resources from the official Web sites of the societies/panels. Sources included guidelines by European Society of Medical Oncology, the Japanese Society for Cancer of the Colon and Rectum, and the National Comprehensive Cancer Network. STUDY SELECTION: Only full-text studies and the latest guidelines dealing with colon cancer were included. Studies and guidelines were separately assessed by 2 authors, who independently identified discrepancies and areas for further research. These were discussed and agreed with by all the authors. MAIN OUTCOME MEASURES: The recommendations of the guidelines of each society were compared, seeking discrepancies and potential areas for improvement. RESULTS: Endoscopic techniques for the management of early colon cancer are discussed in detail in the Asian guidelines. Asian guidelines advocate extended (D3) lymphadenectomy on a routine basis in T3/T4 and in selected T2 patients, whereas such an approach is still under investigation in Western countries. Only US guidelines describe neoadjuvant chemotherapy and radiotherapy. All the guidelines recommend adjuvant treatment in selected stage II patients, but agreement exists that this is performed without solid evidence, because better outcomes are hypothesized based on studies including stage III or stage II/III patients. The role of cytoreductive surgery with intra-abdominal chemotherapy is dubious, and European guidelines only recommend it in the setting of trials. Asian guidelines endorse an aggressive surgical approach to peritoneal disease. Only US guidelines include a patient advocate in the drafting panel. LIMITATIONS: Bias may have arisen from country-specific socioeconomic and cultural issues, and from the latest available updates. CONCLUSIONS: Surgical approaches to colon cancer differ significantly among Western and Asian guidelines, reflecting different concepts of treatment. The role of adjuvant treatment in node-negative disease and quality-of-life assessment need further research.


PLOS ONE | 2017

Social media and colorectal cancer: A systematic review of available resources

Gianluca Pellino; Constantinos Simillis; Shengyang Qiu; Shahnawaz Rasheed; Sarah Mills; Oliver Warren; Christos Kontovounisios; Paris P. Tekkis

Aim Social media (SM) can provide information and medical knowledge to patients. Our aim was to review the literature and web-based content on SM that is used by Colorectal Cancer (CRC) patients, as well as surgeons’ interaction with SM. Method Studies published between 2006 and 2016 were assessed. We also assessed the impact of several hashtags on Twitter with a freeware (Symplur). Results Nine studies were included assessing Twitter (78%), Forums/Cancer-survivor networks (33%), and Facebook (22%). Aims included use of SM by CRC patients (67%), cancer-specific usage of SM with different types of cancer (44%), content credibility (33%), and influence in CRC awareness (33%). Prevention was the most common information that CRC patients looked for, followed by treatment side-effects. Only 2% of CRC SM users are doctors. SM use by colorectal consultants was suboptimal. Only 38% of surgeons had a LinkedIn account (most with less than 50 connections), and 3% used Twitter. A steep increase of tweets was observed for searched Hashtags over time, which was more marked for #ColonCancer (+67%vs+38%, #Coloncancer vs #RectalCancer). Participants engaged with colon cancer increased by 85%, whereas rectal cancer ones increased by 29%. The hashtag ‘#RectalCancer’ was mostly tweeted by colorectal surgeons. The official twitter account of American Society of Colorectal Surgeons (@fascrs_updates) was the most active account. Conclusion CRC patients and relatives are increasingly engaging with SM. CRC surgeons’ participation is poor, but we confirm a trend toward a greater involvement. Most SM lack of authoritative validation and the quality of shared content still is largely anecdotic and not scientifically evidenced-based. However, SM may offer several advantages over conventional information sharing sources for CRC patients and surgeons, and create connections with mutual enrichment.


European Journal of Gastroenterology & Hepatology | 2017

Colorectal cancer diagnosed during pregnancy: systematic review and treatment pathways.

Gianluca Pellino; Constantinos Simillis; Christos Kontovounisios; Daniel L. Baird; Stella Nikolaou; Oliver Warren; Paris P. Tekkis; Shahnawaz Rasheed

The aim of this study was to identify the mode of presentation and incidence of colorectal cancer in pregnancy (CRC-p), assess the outcomes of the mother and foetus according to gestational age, treatment delivered and cancer features and location. A systematic review of the literature was carried out to identify studies reporting on CRC-p and pooled analysis of the reported data. Seventy-nine papers reporting on 119 patients with unequivocal CRC-p were included. The calculated pooled risk is 0.002% and age at diagnosis has decreased over time. The median age at diagnosis was 32 (range, 17–46) years. Twelve per cent, 41 and 47% of CRC-p were diagnosed during the first, second and third trimester. The CRC-p site was the colon in 53.4% of cases, the rectum in 44% and multiple sites in 2.6%. Bleeding occurred in 47% of patients, abdominal pain in 37.6%, constipation in 14.1%, obstruction in 9.4% and perforation in 2.4%. Out of 82 patients whose treatment was described, 9.8% received chemotherapy during pregnancy. None of their newborns developed permanent disability, one developed hypothyroidism and 72% of newborns were alive. Vaginal delivery was possible in 60% of cases. Anterior resection was performed in 30% of patients and abdominoperineal excision of the rectum in 14.9%. Five patients had either synchronous (60%) or metachronous liver resection (40%). The median survival in these patients was 42 (0–120) months. Fifty-five per cent of patients were alive at the last available follow-up. The median survival of the mother was 36 (0–360) months. Patients with rectal cancer had longer survival compared with patients with colon cancer (P=0.0072). CRC-p is rare, leading to symptoms being overlooked, and diagnosis made at advanced stages. Cases described in the literature include patients who had cancer before pregnancy or developed it after delivery. Survival has not increased over time and the management of these patients requires collaboration between specialties and active interaction with the patients.


Acta Chirurgica Belgica | 2017

A comparative study of short-term outcomes of colorectal cancer surgery in the elderly population

C. Yen; Constantinos Simillis; Mariam Choudhry; Sarah Mills; Oliver Warren; Paris P. Tekkis; Christos Kontovounisios

Abstract Background: Colorectal Cancer (CRC) is a disease of the elderly, and with an ageing population, oncological surgical procedures for CRC in the elderly is expected to increase. However, the balance between surgical benefits and risks associated with age and comorbidities in elderly patients is obscure. Materials and methods: A retrospective database of consecutive patients who received CRC surgery was used to compare short-term surgical and oncological outcomes between patients aged ≥75 and <75 years old undergoing CRC resection. Results: There were 54 patients (63.5%) in the <75 group and 31 patients (36.5%) in the ≥75 group. Overall, there were no differences between the <75 and ≥75 groups in postoperative HDU/ITU stay, median hospital LOS or 30-day mortality rates. Patients ≥75 had a higher preoperative performance status (25.9% versus 71.0%, p < .001), but no difference in ASA Grade and referral pattern, proportion of emergency operations, cancer staging, resection margins, achievement of curative resection or median lymph node yield. There was a significantly higher use of adjuvant chemotherapy in the <75 age group (48.1% versus 25.8%, p = .043). Conclusions: With adequate patient selection, CRC resection in elderly patients is not associated with higher postoperative mortality or worse short-term oncological benefits.

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Ara Darzi

Imperial College London

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Paris P. Tekkis

The Royal Marsden NHS Foundation Trust

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Gianluca Pellino

Instituto Politécnico Nacional

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Sarah Mills

Imperial College London

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Shahnawaz Rasheed

The Royal Marsden NHS Foundation Trust

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