Partitioning a matrix with non-guillotine cuts to minimize the maximum cost

none2noWe consider the problem of partitioning a matrix of m rows and n columns of non-negative integers into M smaller submatrices. With each submatrix is associated a cost equal to the sum of its elements. The objective is to minimize the cost of the submatrix of maximum cost. We present a (O-l)-integer programming formulation of the problem and three different lower bounds. A heuristic procedure for finding a valid upper bound to the optimal solution cost is also described. Problem reduction tests derived from both the original problem and the lower bounds are given. Lower bounds and reduction tests are used in a tree search algorithm in order to find the optimal solution to the problem. Computational results on a number of randomly generated test problems are presented. © 2002 Elsevier Science B.V. AU rights reserved.noneMingozzi A.; Morigi S.Mingozzi A.; Morigi S

Nurse-managed basal-bolus versus sliding-scale insulin regimen in subjects with hyperglycemia at admission for orthopedic surgery: a propensity score approach

Aims: A sliding-scale (SS) regimen is discouraged to correct hyperglycemia in hospital patients, but there is resistance to adoption of basal-bolus (BB) treatment in surgical units. We tested the feasibility and the effects of a nurse-based BB regimen in orthopedic surgery. Methods: Following an intense training to implement a protocol amenable by nurses, a group of patients admitted with hyperglycemia in an orthopedic institute were prospectively followed according to a basal-bolus insulin regimen (BB, n = 80). They were compared with a hyperglycemic group eventually treated by sliding-scale insulin on demand (SS, n = 122). Diabetes was present in 196 cases. Metabolic control was assessed during the first 3 days of surgery; outcome data were tested by logistic regression, after adjusting for propensity score. Result: Average blood glucose and glucose variability were lower in BB versus SS (P < 0.001), in the presence of similar 3-day insulin doses. Complications were recorded in 68 cases (16.2% vs. 45.1% in BB and SS, respectively). BB regimen was associated with propensity-adjusted reduction in all adverse events [odds ratio (OR) 0.36; 95% confidence interval (CI) 0.17-0.76] and of systemic infections (OR 0.18; 95% CI 0.07-0.50) and with shorter hospital stay (8.8 \ub1 SD 5.2 days vs. 12.5 \ub1 7.4; P < 0.01). The superiority of BB regimen was confirmed in the pair-matched analysis. Conclusions: The study proves the feasibility and the superiority of nurse-based BB versus SS treatment in metabolic control and on the risk of adverse events in orthopedic surgery patients with hyperglycemia

Management and outcomes in critically ill nonagenarian versus octogenarian patients

Background: Intensive care unit (ICU) patients age 90 years or older represent a growing subgroup and place a huge financial burden on health care resources despite the benefit being unclear. This leads to ethical problems. The present investigation assessed the differences in outcome between nonagenarian and octogenarian ICU patients. Methods: We included 7900 acutely admitted older critically ill patients from two large, multinational studies. The primary outcome was 30-day-mortality, and the secondary outcome was ICU-mortality. Baseline characteristics consisted of frailty assessed by the Clinical Frailty Scale (CFS), ICU-management, and outcomes were compared between octogenarian (80-89.9 years) and nonagenarian (>= 90 years) patients. We used multilevel logistic regression to evaluate differences between octogenarians and nonagenarians. Results: The nonagenarians were 10% of the entire cohort. They experienced a higher percentage of frailty (58% vs 42%; p < 0.001), but lower SOFA scores at admission (6 +/- 5 vs. 7 +/- 6; p < 0.001). ICU-management strategies were different. Octogenarians required higher rates of organ support and nonagenarians received higher rates of life-sustaining treatment limitations (40% vs. 33%; p < 0.001). ICU mortality was comparable (27% vs. 27%; p = 0.973) but a higher 30-day-mortality (45% vs. 40%; p = 0.029) was seen in the nonagenarians. After multivariable adjustment nonagenarians had no significantly increased risk for 30-day-mortality (aOR 1.25 (95% CI 0.90-1.74; p = 0.19)). Conclusion: After adjustment for confounders, nonagenarians demonstrated no higher 30-day mortality than octogenarian patients. In this study, being age 90 years or more is no particular risk factor for an adverse outcome. This should be considered- together with illness severity and pre-existing functional capacity - to effectively guide triage decisions