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.

SARS-CoV-2 has been associated with an increased rate of venous thromboembolism in critically ill patients. Since surgical patients are already at higher risk of venous thromboembolism than general populations, this study aimed to determine if patients with peri-operative or prior SARS-CoV-2 were at further increased risk of venous thromboembolism. We conducted a planned sub-study and analysis from an international, multicentre, prospective cohort study of elective and emergency patients undergoing surgery during October 2020. Patients from all surgical specialties were included. The primary outcome measure was venous thromboembolism (pulmonary embolism or deep vein thrombosis) within 30 days of surgery. SARS-CoV-2 diagnosis was defined as peri-operative (7 days before to 30 days after surgery); recent (1-6 weeks before surgery); previous (≥7 weeks before surgery); or none. Information on prophylaxis regimens or pre-operative anti-coagulation for baseline comorbidities was not available. Postoperative venous thromboembolism rate was 0.5% (666/123,591) in patients without SARS-CoV-2; 2.2% (50/2317) in patients with peri-operative SARS-CoV-2; 1.6% (15/953) in patients with recent SARS-CoV-2; and 1.0% (11/1148) in patients with previous SARS-CoV-2. After adjustment for confounding factors, patients with peri-operative (adjusted odds ratio 1.5 (95%CI 1.1-2.0)) and recent SARS-CoV-2 (1.9 (95%CI 1.2-3.3)) remained at higher risk of venous thromboembolism, with a borderline finding in previous SARS-CoV-2 (1.7 (95%CI 0.9-3.0)). Overall, venous thromboembolism was independently associated with 30-day mortality ). In patients with SARS-CoV-2, mortality without venous thromboembolism was 7.4% (319/4342) and with venous thromboembolism was 40.8% (31/76). Patients undergoing surgery with peri-operative or recent SARS-CoV-2 appear to be at increased risk of postoperative venous thromboembolism compared with patients with no history of SARS-CoV-2 infection. Optimal venous thromboembolism prophylaxis and treatment are unknown in this cohort of patients, and these data should be interpreted accordingly.

Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? A lot of information has been gathered on the subject of complications following urinary bladder augmentation and/or substitution in the recent years. The present study, based on the analysis of 86 patients, gives a critical analysis of these complications (stone formation, bowel obstruction, hematuria‐dysuria syndrome, small bowel bacterial overgrowth, persistent vesico‐ureteral reflux, obstruction at the site of ureteral reimplantation, reservoir perforation, premalignant histological changes, decreased bladder capacity/compliance requiring reaugmentation, etc.). The study adds one more new complication (small bowel colonization following colocystoplasty performed with the cecum and ascending colon) and reports complications in a fairly big (by European standards) cohort of patients with a long follow‐up. OBJECTIVE To evaluate complications after urinary bladder augmentation or substitution in a prospective study in children. PATIENTS AND METHODS Data of 86 patients who underwent urinary bladder augmentation (80 patients) or substitution (6 patients) between 1988 and 2008 at the authors’ institute were analysed. Ileocystoplasty occurred in 32, colocystoplasty in 30 and gastrocystoplasty in 18. Urinary bladder substitution using the large bowel was performed in six patients. All patients empty their bladder by intermittent clean catheterization (ICC), 30 patients via their native urethra and 56 patients through continent abdominal stoma. Mean follow‐up was 8.6 years. Rate of complications and frequency of surgical interventions were statistically analysed (two samples t‐test for proportions) according to the type of gastrointestinal part used. RESULTS In all, 30 patients had no complications. In 56 patients, there were a total of 105 complications (39 bladder stones, 16 stoma complications, 11 bowel obstructions, 5 reservoir perforations, 7 VUR recurrences, 1 ureteral obstruction, 4 vesico‐urethral fistulae, 4 orchido‐epididymitis, 4 haematuria‐dysuria syndrome, 3 decreased bladder capacity/compliance, 3 pre‐malignant histological changes, 1 small bowel bacterial overgrowth and 7 miscellaneous). In 25 patients, more than one complication occurred and required 91 subsequent surgical interventions. Patients with colocystoplasty had significantly more complications (P < 0.05), especially more stone formation rate (P < 0.001) and required more post‐ operative interventions (P < 0.05) than patients with gastrocystoplasty and ileocystoplasty. CONCLUSIONS Urinary bladder augmentation or substitution is associated with a large number of complications, particularly after colocystoplasty. Careful patient selection, adequate preoperative information and life‐long follow‐up are essential for reduction, early detection and management of surgical and metabolic complications in patients with bladder augmentation or substitution.

SUMMARYThis paper is concerned with the development of a 'best' rank one transitive approximation to a general paired comparison matrix in a least-squares sense. A direct attack on the non-linear problem is frequently replaced by a sub-optimal linear problem and, here, the best procedure of this kind is obtained. The Newton-Kantorovich method for the solution of the non-linear problem is also studied, including the role of the best linear approximation as a starting point for this method. Numerical examples are included.

The correct estimation of spill, or passenger demand turned away, is an integral part of the determination of optimal aircraft capacities in the airline fleet assignment process. While making advances in the solution of the large-scale fleet assignment optimization problem, airlines have continued to use an aggregate approach to spill estimation. This aggregate approach ignores the effects of yield management practices that have been widely implemented by airlines during the past decade. In this paper, we illustrate the importance of incorporating the effects of yield management booking limits into the methodology used to estimate both the number of passengers spilled at a given aircraft capacity and their associated revenue value. We describe an approach to spill estimation that makes use of the detailed demand information provided by yield management systems, and we present recursive algorithms that can be used to obtain more accurate spill estimates in cases when multiple booking classes are used. Numerical examples are presented to illustrate the extent to which the outcomes of the different estimation approaches differ, suggesting that these differences can be large enough to have an impact on optimal fleet assignment.