Identifying malnutrition in emergency general surgery: systematic review

Background Emergency general surgery practice is high risk. Surgery is a key part of treatment, with resultant catabolic stress and frequent need for nutritional support. The aim of this study was to examine the current methods of defining and determining malnutrition in emergency general surgery. This included examining the use of nutrition screening and assessment tools and other measures of malnutrition. Methods MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, trial registries, and relevant journals published between January 2000 and January 2022 were searched for studies of adult patients with any emergency general surgery diagnosis, managed conservatively or operatively, with an assessment of nutritional status. Mixed populations were included if more than 50 per cent of patients were emergency general surgery patients or emergency general surgery results could be separately extracted. Studies in which patients had received nutritional support were excluded. The protocol was registered with PROSPERO, the international prospective register of systematic reviews (CRD42021285897). Results From 6700 studies screened, 324 full texts were retrieved and 31 were included in the analysis. A definition of malnutrition was provided in 23 studies (75 per cent), with nutritional status being determined by a variety of methods. A total of seven nutrition screening tools and a total of nine ‘assessment’ tools were reported. To define malnutrition, the most commonly used primary or secondary marker of nutritional status was BMI, followed by albumin level. Conclusion Wide variation exists in approaches to identify malnutrition risk in emergency general surgery patients, using a range of tools and nutrition markers. Future studies should seek to standardize nutrition screening and assessment in the emergency general surgery setting as two discrete processes. This will permit better understanding of malnutrition risk in surgical patients

Female polyandry under male harassment: the case of the common toad (Bufo bufo)

Several recent studies have demonstrated the occurrence of multiple paternity in anuran amphibians, implying that it is more common than previously thought. However, an adaptive explanation for polyandry in anurans is still lacking. The common toad Bufo bufo is an explosively breeding species that releases its eggs in strings. The operational sex ratio (OSR) is male biased, causing strong scramble competition among males; females can even drown through harassment during multiple amplexi. We used microsatellite markers to determine patterns of paternity in natural B. bufo populations and experimentally mated individuals (females exposed to either two or six males). Thirty per cent of field-collected and 22% of experimentally produced egg strings were sired by at least two males; all others were sired by a single father. Multiple paternities arose only from multiple amplexi, and we found no indication of fertilization from non-amplexing males, for example through free-swimming sperm. Our results suggest that polyandry in B. bufo is likely to occur most often at high population densities, and under the most male-biased OSRs. Moreover, polyandry might be interpreted as being the consequence of females spawning when amplexed by a few males, to avoid the risk of drowning by amplexus with multiple males

Long-term fitness benefits of polyandry in a small mammal, the bank vole Clethrionomys glareolus

Polyandry, i.e. mating with multiple males within one reproductive event, is a common female mating strategy but its adaptive function is often unclear. We tested whether polyandrous females gain genetic benefits by comparing fitness traits of monandrous (mated twice with a single male) and polyandrous (mated twice with two different males) female bank voles Clethrionomys glareolus. We raised the offspring in the laboratory until adulthood and measured their body size, before releasing them to outdoor enclosures to overwinter. At the onset of the breeding season in the following spring, we found that offspring of polyandrous females performed significantly better at reproduction than those of monandrous females. This was mainly due to sons of polyandrous females producing significantly more offspring than those of monandrous females. No significant differences were found for offspring body mass or winter survival between the two treatments. Our results appear to provide evidence that bank vole females gain long-term benefits from polyandry