ORCID Profile
0000-0001-9221-6674
Current Organisation
The University of Auckland
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Publisher: Wiley
Date: 30-11-2020
DOI: 10.1111/CODI.14899
Abstract: Gastrointestinal recovery describes the restoration of normal bowel function in patients with bowel disease. This may be prolonged in two common clinical settings: postoperative ileus and small bowel obstruction. Improving gastrointestinal recovery is a research priority but researchers are limited by variation in outcome reporting across clinical studies. This protocol describes the development of core outcome sets for gastrointestinal recovery in the contexts of postoperative ileus and small bowel obstruction. An international Steering Group consisting of patient and clinician representatives has been established. As overlap between clinical contexts is anticipated, both outcome sets will be co-developed and may be combined to form a common output with disease-specific domains. The development process will comprise three phases, including definition of outcomes relevant to postoperative ileus and small bowel obstruction from systematic literature reviews and nominal-group stakeholder discussions online-facilitated Delphi surveys via international networks and a consensus meeting to ratify the final output. A nested study will explore if the development of overlapping outcome sets can be rationalized. The final output will be registered with the Core Outcome Measures in Effectiveness Trials initiative. A multi-faceted, quality improvement c aign for the reporting of gastrointestinal recovery in clinical studies will be launched, targeting international professional and patient groups, charitable organizations and editorial committees. Success will be explored via an updated systematic review of outcomes 5 years after registration of the core outcome set.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 2021
Publisher: Wiley
Date: 13-08-2019
DOI: 10.1111/NMO.13704
Abstract: High-resolution colonic manometry is an emerging technique that has provided new insights into the pathophysiology of functional colorectal diseases. Prior studies have been limited by bulky, non-ambulatory acquisition systems, which have prevented mobilization during prolonged recordings. A novel ambulatory acquisition system for fiber-optic high-resolution colonic manometry was developed. Benchtop validation against a standard non-ambulatory system was performed using standardized calibration metrics. Clinical feasibility studies were conducted in three patients undergoing right hemicolectomy. Pressure profiles obtained from benchtop testing were near-identical using the ambulatory and the non-ambulatory systems. Clinical studies successfully demonstrated ambulatory data capture with patients freely mobilizing postoperatively during continuous recordings of >60 hours. The occurrence (P = .56), litude (P = .65), velocity (P = .10), and extent (P = .12) of colonic motor patterns were similar to those obtained in non-ambulatory studies. A novel ambulatory system for high-resolution colonic manometry has been developed and validated. This technique will facilitate prolonged ambulatory recordings of colonic motor activity, assisting with investigations into the role of colonic motility in disease states.
Publisher: Wiley
Date: 11-2020
DOI: 10.1111/ANS.16333
Publisher: Oxford University Press (OUP)
Date: 24-03-2021
DOI: 10.1093/BJS/ZNAB101
Abstract: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351 best case 196, worst case 816) or non-cancer surgery (733 best case 407, worst case 1664). Both exceeded the NNV in the general population (1840 best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.
Publisher: Wiley
Date: 18-09-2020
DOI: 10.1111/CODI.15311
Abstract: Aspiration is a common cause of pneumonia in patients with postoperative ileus. Insertion of a nasogastric tube (NGT) is often performed, but this can be distressing. The aim of this study was to determine whether the timing of NGT insertion after surgery (before versus after vomiting) was associated with reduced rates of pneumonia in patients undergoing elective colorectal surgery. This was a preplanned secondary analysis of a multicentre, prospective cohort study. Patients undergoing elective colorectal surgery between January 2018 and April 2018 were eligible. Those receiving a NGT were ided into three groups, based on the timing of the insertion: routine NGT (inserted at the time of surgery), prophylactic NGT (inserted after surgery but before vomiting) and reactive NGT (inserted after surgery and after vomiting). The primary outcome was the development of pneumonia within 30 days of surgery, which was compared between the prophylactic and reactive NGT groups using multivariable regression analysis. A total of 4715 patients were included in the analysis and 1536 (32.6%) received a NGT. These were classified as routine in 926 (60.3%), reactive in 461 (30.0%) and prophylactic in 149 (9.7%). Two hundred patients (4.2%) developed pneumonia (no NGT 2.7% routine NGT 5.2% reactive NGT 10.6% prophylactic NGT 11.4%). After adjustment for confounding factors, no significant difference in pneumonia rates was detected between the prophylactic and reactive NGT groups (odds ratio 1.03, 95% CI 0.56–1.87, P = 0.932). In patients who required the insertion of a NGT after surgery, prophylactic insertion was not associated with fewer cases of pneumonia within 30 days of surgery compared with reactive insertion.
Publisher: Wiley
Date: 11-01-2023
DOI: 10.1111/CODI.16467
Abstract: Readmissions after colorectal cancer surgery are common, despite advancements in surgical care, and have a significant impact on both in idual patients and overall healthcare costs. The aim of this study was to determine the 30‐and 90 days readmission rate after colorectal cancer surgery, and to investigate the risk factors and clinical reasons for unplanned readmissions. A multicenter, population‐based study including all patients discharged after index colorectal cancer resection from 2010 to 2020 in Aotearoa New Zealand (AoNZ) was completed. The Ministry of Health National Minimum Dataset was used. Rates of readmission at 30 days and 90 days were calculated. Mixed‐effect logistic regression models were built to investigate factors associated with unplanned readmission. Reasons for readmission were described. Data were obtained on 16,885 patients. Unplanned 30‐day and 90‐day hospital readmission rates were 15.1% and 23.7% respectively. The main readmission risk factors were comorbidities, advanced disease, and postoperative complications. Hospital level variation was not present. Despite risk adjustment, R 2 value of models was low (30 days: 4.3%, 90 days: 5.2%). The most common reasons for readmission were gastrointestinal causes (32.1%) and wound complications (14.4%). Rates of readmission did not improve over the 11 years study period ( p = 0.876). Readmissions following colorectal resections in AoNZ are higher than other comparable healthcare systems and rates have remained constant over time. While patient comorbidities and postoperative complications are associated with readmission, the explanatory value of these variables is poor. To reduce unplanned readmissions, efforts should be focused on prevention and early detection of post‐discharge complications.
Publisher: Wiley
Date: 11-2021
DOI: 10.14814/PHY2.15091
Publisher: Wiley
Date: 08-2017
DOI: 10.1111/CODI.13767
Abstract: There is increasing awareness of the poor functional outcome suffered by many patients after sphincter-preserving rectal resection, termed 'low anterior resection syndrome' (LARS). There is no consensus definition of LARS and varying instruments have been employed to measure functional outcome, complicating research into prevalence, contributing factors and potential therapies. We therefore aimed to describe the instruments and outcome measures used in studies of bowel dysfunction after low anterior resection and identify major themes used in the assessment of LARS. A systematic review of the literature was performed for studies published between 1986 and 2016. The instruments and outcome measures used to report bowel function after low anterior resection were extracted and their frequency of use calculated. The search revealed 128 eligible studies. These employed 18 instruments, over 30 symptoms, and follow-up time periods from 4 weeks to 14.6 years. The most frequent follow-up period was 12 months (48%). The most frequently reported outcomes were incontinence (97%), stool frequency (80%), urgency (67%), evacuatory dysfunction (47%), gas-stool discrimination (34%) and a measure of quality of life (80%). Faecal incontinence scoring systems were used frequently. The LARS score and the Bowel Function Instrument (BFI) were used in only nine studies. LARS is common, but there is substantial variation in the reporting of functional outcomes after low anterior resection. Most studies have focused on incontinence, omitting other symptoms that correlate with patients' quality of life. To improve and standardize research into LARS, a consensus definition should be developed, and these findings should inform this goal.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2020
DOI: 10.1097/DCR.0000000000001583
Abstract: Low anterior resection syndrome is pragmatically defined as disordered bowel function after rectal resection leading to a detriment in quality of life. This broad characterization does not allow for precise estimates of prevalence. The low anterior resection syndrome score was designed as a simple tool for clinical evaluation of low anterior resection syndrome. Although the low anterior resection syndrome score has good clinical utility, it may not capture all important aspects that patients may experience. The aim of this collaboration was to develop an international consensus definition of low anterior resection syndrome that encompasses all aspects of the condition and is informed by all stakeholders. This international patient-provider initiative used an online Delphi survey, regional patient consultation meetings, and an international consensus meeting. Three expert groups participated: patients, surgeons, and other health professionals from 5 regions (Australasia, Denmark, Spain, Great Britain and Ireland, and North America) and in 3 languages (English, Spanish, and Danish). The primary outcome measured was the priorities for the definition of low anterior resection syndrome. Three hundred twenty-five participants (156 patients) registered. The response rates for successive rounds of the Delphi survey were 86%, 96%, and 99%. Eighteen priorities emerged from the Delphi survey. Patient consultation and consensus meetings refined these priorities to 8 symptoms and 8 consequences that capture essential aspects of the syndrome. S ling bias may have been present, in particular, in the patient panel because social media was used extensively in recruitment. There was also dominance of the surgical panel at the final consensus meeting despite attempts to mitigate this. This is the first definition of low anterior resection syndrome developed with direct input from a large international patient panel. The involvement of patients in all phases has ensured that the definition presented encompasses the vital aspects of the patient experience of low anterior resection syndrome. The novel separation of symptoms and consequences may enable greater sensitivity to detect changes in low anterior resection syndrome over time and with intervention.
Publisher: Oxford University Press (OUP)
Date: 14-04-2018
DOI: 10.1002/BJS.10808
Abstract: Recovery after colonic surgery is invariably delayed by disturbed gut motility. It is commonly assumed that colonic motility becomes quiescent after surgery, but this hypothesis has not been evaluated rigorously. This study quantified colonic motility through the early postoperative period using high-resolution colonic manometry. Fibre-optic colonic manometry was performed continuously before, during and after surgery in the left colon and rectum of patients undergoing right hemicolectomy, and in healthy controls. Motor events were characterized by pattern, frequency, direction, velocity, litude and distance propagated. Eight patients undergoing hemicolectomy and nine healthy controls were included in the study. Colonic motility became markedly hyperactive in all operated patients, consistently dominated by cyclic motor patterns. Onset of cyclic motor patterns began to a minor extent before operation, occurring with increasing intensity nearer the time of surgery the mean(s.d.) active duration was 12(7) per cent over 3 h before operation and 43(17) per cent within 1 h before surgery (P = 0.024) in fasted controls it was 2(4) per cent (P & 0·001). After surgery, cyclic motor patterns increased markedly in extent and intensity, becoming nearly continuous (active duration 94(13) per cent P & 0·001), with peak frequency 2–4 cycles per min in the sigmoid colon. This postoperative cyclic pattern was substantially more prominent than in non-operative controls, including in the fed state (active duration 27(20) per cent P & 0·001), and also showed higher antegrade velocity (P & 0·001). Distal gut motility becomes markedly hyperactive with colonic surgery, dominated by cyclic motor patterns. This hyperactivity likely represents a novel pathophysiological aspect of the surgical stress response. Hyperactive motility may contribute to gut dysfunction after surgery, potentially offering a new therapeutic target to enhance recovery.
Publisher: Wiley
Date: 09-03-2021
DOI: 10.1111/ANAE.15458
Abstract: Peri‐operative SARS‐CoV‐2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS‐CoV‐2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre‐operative SARS‐CoV‐2 infection were compared with those without previous SARS‐CoV‐2 infection. The primary outcome measure was 30‐day postoperative mortality. Logistic regression models were used to calculate adjusted 30‐day mortality rates stratified by time from diagnosis of SARS‐CoV‐2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre‐operative SARS‐CoV‐2 diagnosis. Adjusted 30‐day mortality in patients without SARS‐CoV‐2 infection was 1.5% (95%CI 1.4–1.5). In patients with a pre‐operative SARS‐CoV‐2 diagnosis, mortality was increased in patients having surgery within 0–2 weeks, 3–4 weeks and 5–6 weeks of the diagnosis (odds ratio (95%CI) 4.1 (3.3–4.8), 3.9 (2.6–5.1) and 3.6 (2.0–5.2), respectively). Surgery performed ≥ 7 weeks after SARS‐CoV‐2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5 (0.9–2.1)). After a ≥ 7 week delay in undertaking surgery following SARS‐CoV‐2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2–8.7) vs. 2.4% (95%CI 1.4–3.4) vs. 1.3% (95%CI 0.6–2.0), respectively). Where possible, surgery should be delayed for at least 7 weeks following SARS‐CoV‐2 infection. Patients with ongoing symptoms ≥ 7 weeks from diagnosis may benefit from further delay.
Publisher: Elsevier BV
Date: 12-2020
DOI: 10.1111/NER.13092
Publisher: Wiley
Date: 10-08-2020
DOI: 10.1111/CODI.15275
Abstract: Postoperative drains have historically been used for the prevention and early detection of intra‐abdominal collections. However, current evidence suggests that prophylactic drain placement following colorectal surgery has no significant clinical benefit. This is reflected in the enhanced recovery after surgery (ERAS) guidelines, which recommend against their routine use. The Ileus Management International study found more than one‐third of participating centres across the world routinely used drains in the majority of colorectal resections. The aim of the present study is to audit international compliance with ERAS guidelines regarding the use of postoperative drains in colorectal surgery. This prospective, multicentre audit will be conducted via the student‐ and trainee‐led EuroSurg Collaborative network across Europe, South Africa and Australasia. Data will be collected on consecutive patients undergoing elective and emergency colorectal surgery with 30‐day follow‐up. This will include any colorectal resection, formation of colostomy/ileostomy and reversal of stoma. The primary end‐point will be adherence to ERAS guidelines for intra‐abdominal drain placement. Secondary outcomes will include the following: time to diagnosis of intra‐abdominal postoperative collections output and time to removal of drains and 30‐day postoperative complications defined by the Clavien–Dindo classification. This protocol describes the methodology for the first international audit of intra‐abdominal drain placement after colorectal surgery. The study will be conducted across a large collaborative network with quality assurance and data validation strategies. This will provide a clear understanding of current practice and novel evidence regarding the efficacy and safety of intra‐abdominal drain placement in colorectal surgical patients.
Publisher: Oxford University Press (OUP)
Date: 09-10-2019
DOI: 10.1002/BJS.11326
Abstract: Ileus is common after elective colorectal surgery, and is associated with increased adverse events and prolonged hospital stay. The aim was to assess the role of non-steroidal anti-inflammatory drugs (NSAIDs) for reducing ileus after surgery. A prospective multicentre cohort study was delivered by an international, student- and trainee-led collaborative group. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The primary outcome was time to gastrointestinal recovery, measured using a composite measure of bowel function and tolerance to oral intake. The impact of NSAIDs was explored using Cox regression analyses, including the results of a centre-specific survey of compliance to enhanced recovery principles. Secondary safety outcomes included anastomotic leak rate and acute kidney injury. A total of 4164 patients were included, with a median age of 68 (i.q.r. 57–75) years (54·9 per cent men). Some 1153 (27·7 per cent) received NSAIDs on postoperative days 1–3, of whom 1061 (92·0 per cent) received non-selective cyclo-oxygenase inhibitors. After adjustment for baseline differences, the mean time to gastrointestinal recovery did not differ significantly between patients who received NSAIDs and those who did not (4·6 versus 4·8 days hazard ratio 1·04, 95 per cent c.i. 0·96 to 1·12 P = 0·360). There were no significant differences in anastomotic leak rate (5·4 versus 4·6 per cent P = 0·349) or acute kidney injury (14·3 versus 13·8 per cent P = 0·666) between the groups. Significantly fewer patients receiving NSAIDs required strong opioid analgesia (35·3 versus 56·7 per cent P & 0·001). NSAIDs did not reduce the time for gastrointestinal recovery after colorectal surgery, but they were safe and associated with reduced postoperative opioid requirement.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2020
DOI: 10.1016/J.IJSU.2019.12.003
Abstract: Postoperative pancreatic fistula (POPF) remains a major cause of morbidity following pancreaticoduodenectomy (PD). This network meta-analysis (NMA) compared techniques of pancreatic anastomosis following PD to determine the technique with the best outcome profile. A systematic literature search was performed on the Scopus, EMBASE, Medline and Cochrane databases to identify RCTs employing the international study group of pancreatic fistula (ISGPF) definition of POPF. The primary outcome was clinically relevant POPF. Five techniques of pancreatic anastomosis following PD were directly compared in 15 RCTs comprising 2428 patients. Panreatojejunostomy (PJ) end-to-side invagination vs. PJ end-to-side duct-to-mucosa was the most frequent comparison (n = 7). Overall, 971 patients underwent PJ end-to-side duct-to-mucosa, 791 patients PJ end-to-side invagination, 505 patients pancreatogastrostomy (PG) end-to-side invagination, 98 patients PG end-to-side duct-to-mucosa, and 63 patients PJ end-to-side single layer. PG duct-to-mucosa was associated with the lowest rates of clinically relevant POPF, delayed gastric emptying, intra-abdominal abscess, all postoperative morbidity and postoperative mortality, the shortest operative time and postoperative hospital stay and the lowest volume of intra-operative blood loss. Duct-to-mucosa pancreaticogastrostomy was associated with the lowest rates of clinically relevant POPF and had the best outcome profile among all techniques of pancreatico-anastomosis following PD.
Publisher: Oxford University Press (OUP)
Date: 24-01-2020
DOI: 10.1002/BJS.11422
Abstract: Ileus is common after colorectal surgery and is associated with an increased risk of postoperative complications. Identifying features of normal bowel recovery and the appropriateness for hospital discharge is challenging. This study explored the safety of hospital discharge before the return of bowel function. A prospective, multicentre cohort study was undertaken across an international collaborative network. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The main outcome of interest was readmission to hospital within 30 days of surgery. The impact of discharge timing according to the return of bowel function was explored using multivariable regression analysis. Other outcomes were postoperative complications within 30 days of surgery, measured using the Clavien–Dindo classification system. A total of 3288 patients were included in the analysis, of whom 301 (9·2 per cent) were discharged before the return of bowel function. The median duration of hospital stay for patients discharged before and after return of bowel function was 5 (i.q.r. 4–7) and 7 (6–8) days respectively (P & 0·001). There were no significant differences in rates of readmission between these groups (6·6 versus 8·0 per cent P = 0·499), and this remained the case after multivariable adjustment for baseline differences (odds ratio 0·90, 95 per cent c.i. 0·55 to 1·46 P = 0·659). Rates of postoperative complications were also similar in those discharged before versus after return of bowel function (minor: 34·7 versus 39·5 per cent major 3·3 versus 3·4 per cent P = 0·110). Discharge before return of bowel function after elective colorectal surgery appears to be safe in appropriately selected patients.
No related grants have been discovered for Cameron Wells.