Which interventions with youths counter ageism toward older adults? Results from a realist review.

Age-related social biases - ageism - are developed at an early age. Interventions to counter ageism have been identified but little is known about their mechanisms, particularly in children. This study aimed to provide a comprehensive understanding of which interventions in youths are most effective, under which circumstances, how, and with what outcomes. Using 46 keywords in 6 databases, a realist review identified 24 studies published between 2000 and 2022 targeting youths under 18. A content analysis of these studies led to the construction of a Context-Mechanisms-Outcomes explanatory model. Contextual facilitators triggering mechanisms for changing stereotypes, prejudices and discrimination were: 1) enhancing knowledge about aging and older adults by providing nuanced information, 2) improving the quality of intergenerational contacts, 3) increasing opportunities to apply previously acquired knowledge in intergenerational interactions, and 4) promoting reflective thinking about experiences with older adults. However, stereotypes and prejudices appeared to be resistant and changes difficult to generalize. Insufficiently advanced cognitive development in children or viewing healthy and socially engaged older adults as unrepresentative of their age group were obstacles that reduced intervention effectiveness. Future studies should explore how advancing age influences interventions as well as the characteristics of older adults involved.

Flip Distances Between Graph Orientations.

Flip graphs are a ubiquitous class of graphs, which encode relations on a set of combinatorial objects by elementary, local changes. Skeletons of associahedra, for instance, are the graphs induced by quadrilateral flips in triangulations of a convex polygon. For some definition of a flip graph, a natural computational problem to consider is the flip distance: Given two objects, what is the minimum number of flips needed to transform one into the other? We consider flip graphs on orientations of simple graphs, where flips consist of reversing the direction of some edges. More precisely, we consider so-called α -orientations of a graph G, in which every vertex v has a specified outdegree α ( v ) , and a flip consists of reversing all edges of a directed cycle. We prove that deciding whether the flip distance between two α -orientations of a planar graph G is at most two is NP-complete. This also holds in the special case of perfect matchings, where flips involve alternating cycles. This problem amounts to finding geodesics on the common base polytope of two partition matroids, or, alternatively, on an alcoved polytope. It therefore provides an interesting example of a flip distance question that is computationally intractable despite having a natural interpretation as a geodesic on a nicely structured combinatorial polytope. We also consider the dual question of the flip distance between graph orientations in which every cycle has a specified number of forward edges, and a flip is the reversal of all edges in a minimal directed cut. In general, the problem remains hard. However, if we restrict to flips that only change sinks into sources, or vice-versa, then the problem can be solved in polynomial time. Here we exploit the fact that the flip graph is the cover graph of a distributive lattice. This generalizes a recent result from Zhang et al. (Acta Math Sin Engl Ser 35(4):569-576, 2019).

Phosphate addition to hemodiafiltration solutions during continuous renal replacement therapy.

OBJECTIVE: Hypophosphatemia often occurs during continuous renal replacement therapy (CRRT). The addition of phosphate to dialysate and replacement solutions facilitates phosphate handling, but the risk of precipitation with calcium within these solutions has not been addressed. DESIGN AND SETTING: Experimental study with a retrospective observational study in a medico-surgical intensive care unit. METHODS AND PATIENTS: We tested the addition of phosphate to calcium-rich lactate- and bicarbonate-based solutions (Hemosol LG2 and Hemosol B0) used in CRRT to see whether precipitation occurs. Two milliliters of potassium phosphate added to 5-l bags gives a physiological phosphate concentration of 1.2 mmol/l. In addition, calcium and phosphate homeostasis was retrospectively evaluated in 20 consecutive CRRT patients where potassium phosphate had been added to these solutions. MEASUREMENTS AND RESULTS: Total and ionized calcium, phosphate, pH, PCO(2) and bicarbonate remained essentially unchanged 5 h after the addition of 2 ml of potassium phosphate to 5-l Hemosol solutions. Visual inspection did not reveal any precipitate. Of the 20 patients studied, 14 received more than 24 h of phosphate supplementation to dialysate and replacement solutions. Phosphate remained stable throughout CRRT despite phosphate intake from nutrition in 11 cases. No adverse event was noted on potassium, calcium, pH and bicarbonate homeostasis. CONCLUSIONS: The addition of phosphate to Hemosol solutions does not precipitate with the calcium within these solutions. This practical method effectively prevents hypophosphatemia in CRRT patients.

Continuous renal replacement therapy after cardiac surgery. Review of 85 cases.

BACKGROUND/AIMS: To evaluate the outcome of patients who require continuous renal replacement therapy (CRRT) following cardiac surgery. METHODS: All patients who received CRRT after cardiac surgery over more than 4 years at the Surgical Intensive Care Unit of the Montreal Heart Institute were reviewed. Among 5,564 consecutive patients, 85 underwent CRRT postoperatively. RESULTS: The mean delay between surgery and CRRT initiation was 5 days, and the duration of CRRT was 9 days, without a difference between survivors and non-survivors. Delivered clearances with CRRT were estimated at 25-28 ml/min (approximately 40 liters/day), 29-32 ml/min (approximately 46 liters/day) and 17 ml/min (approximately 25 liters/day) for continuous veno-venous hemofiltration, continuous veno-venous hemodiafiltration and continuous veno-venous hemodialysis, respectively. In-hospital mortality was 43.5%. No difference in mortality was observed between patients with normal renal function at baseline and those with pre-operative renal dysfunction. Mortality was 33.3% after a coronary artery bypass graft (CABG), 57.1% after CABG and valve surgery, 60% after valve surgery, and 72.7% for redo-CABG or redo-valve surgery. 79% of survivors and 86% of non-survivors had received a cardiopulmonary bypass (p = NS). The Simplified Acute Physiology Score II upon intensive care unit (ICU) admission and the requirement of an intra-aortic balloon pump were higher in non-survivors (p < 0.05). The mean length of ICU and hospital stay was 27.4 and 34.2 days for survivors and 17.9 and 22.3 days for non-survivors, respectively (p < 0.05). CONCLUSIONS: Renal impairment is relatively common after cardiac surgery. The mortality of patients who required CRRT after cardiac surgery was 43.5% and was particularly influenced by the type of surgery.

Solute clearances during continuous venovenous haemofiltration at various ultrafiltration flow rates using Multiflow-100 and HF1000 filters.

BACKGROUND: In continuous venovenous haemofiltration (CVVH), high ultrafiltration rates provide survival benefits in acute renal failure. This study measured clearances obtained at ultrafiltration rates of up to 4.5 l/h. METHODS: Clearances of small solutes (urea, creatinine, phosphate and urate) and of beta(2)-microglobulin (beta(2)-M) were measured during CVVH. Five preset Multiflow-100 (M-100) and five HF1000 hollow-fibre filters were compared. For the M-100, clearances obtained by haemofiltration were compared with those obtained by haemodiafiltration at similar total effluent rates from a previous study. RESULTS: For small solutes, the effluent to plasma ratio (E/P) remained close to 1.0 at all ultrafiltration rates; filter clearances were thus equal to Quf for both filters. Increasing Quf from 1.0 to 4.5 l/h did not significantly modify E/P. Convective clearances of beta(2)-M were lower than those obtained for small solutes. For the M-100, average beta(2)-M E/P was 0.62+/-0.10 and did not significantly change while increasing Quf. For the HF1000, average beta(2)-M E/P were significantly lower compared with the M-100 (0.42+/-0.09 at 1.0 l/h) and decreased progressively to 0.26+/-0.06 while increasing Quf to 4.5 l/h. With pre-dilution, progressive decreases in clearances delivered to patients were observed reaching 40% at a Quf rate of 4.5 l/h. There was no clinically significant adsorption of beta(2)-M. For the M-100, at similar total effluent flow rates, clearances delivered to patients using haemodiafiltration were significantly higher for small solutes but lower for beta(2)-M in comparison to haemofiltration only. CONCLUSIONS: Filter clearance for small solutes equalled Quf at evaluated rates. At high ultrafiltration rates there was significant loss of clearances with pre-dilution. At similar total effluent rates with the use of pre-dilution, haemodiafiltration is superior to haemofiltration for small solute clearance but inferior for beta(2)-M.