Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Degree of approximation of functions belonging to Lipα class and weighted (L<SUP>r</SUP>,ξ(t)) class by product summability method

A good amount of work has been done on degree of approximation of functions belonging to Lipα, Lip(α,r), Lip(ξ(t),r) and W(Lr, ξ(t)) classes using Cesàro and (generalized) Nörlund single summability methods by a number of researchers like Alexits, Sahney, Goel, Qureshi, Neha, Chandra, Khan, Leindler and Rhoades. But till now no work seems to have been done so far in the direction of present work. Therefore, in present paper, two quite new results on degree of approximation of functions f∈ Lipα and f∈ W(Lr,ξ(t)) class by (E,1)(C,1) product summability means of Fourier series have been obtained

On approximation of functions by product operators

In the present paper, two quite new reults on the degree of approximation of a function f belonging to the class Lip(α,r), 1≤ r <∞ and the weighted class W(Lr,ξ(t)), 1≤ r <∞ by (C,2)(E,1) product operators have been obtained. The results obtained in the present paper generalize various known results on single operators

On almost (N,p,q) summability of conjugate Fourier series

A new theorem on almost generalized Nörlund summability of conjugate series of Fourier series has been established under a very general condition

Degree of approximation of conjugate of a function belonging to Lip(ξ(t),p) class by matrix summability means of conjugate Fourier series

We determine the degree of approximation of conjugate of a function belonging to Lip(ξ(t),p) class by matrix summability means of a conjugate series of a Fourier series

P A ON (E,1)(C,1) SUMMABILITY OF FOURIER SERIES AND ITS CONJUGATE SERIES

[2] have studied (N, p n ) , (N, p, q), almost (N, p, q) and matrix summability methods of Fourier series and its conjugate series using different conditions. But nothing seems to have been done so far to study (E, 1)(C, 1) product summability of Fourier series and its conjugate series. Therefore, in this paper, two theorems on (E, 1)(C, 1) summability of Fourier series and its conjugate series under a general condition have been proved

A study on almost matrix summability of Fourier-Jacobi series

In this paper, a quite new theorem on almost summability of Fourier-Jacobi series has been established. Our theorem extends and generalizes all previously known results of this line of work