8 research outputs found

    Intra-specific variations in the life-history traits of two lacunids (Gastropoda : Prosobranchia)

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    Within life-history trait variations for two herbivorous intertidal lacunids, Lacuna pallidula, a direct developer and Lacuna vincta a planktotroph, were compared and related to their ecology and to marine invertebrate life-history theory. Aspects of life-history theory covered included; reproductive investment, the relationship between egg size and egg fecundity, the Egg-Juvenile-Period (EJP), the implications of egg size for offspring status and maternal effects. Similar patterns of growth and reproductive investment were observed for adult females of both species, although absolute rates of growth and reproduction were differently affected by macroalgal diet. Further, differences in response to the favourability of macroalgal diet were observed for the two species, notably in the manner in which eggs were packaged. Variations in both egg size and egg numbers in spawn masses were observed for the two species, among populations within both species and within Lacuna pallidula populations. For Lacuna pallidula, these variations were shown to be mediated by both maternal macroalgal diet and population source. Maternal diet directly affected the size of hatching offspring but not the size of eggs produced. Consequently, egg size was not a good indicator of hatching size for either species. The EJP was determined for both species for a range of temperatures. Greater variations in the EJP and juvenile size were observed in Lacuna vincta. This was attributed to the ability of the larvae of this species to delay metamorphosis and to display positive growth during the delay phase. Both temperature and microalgal diet were shown to affect patterns of growth and development in Lacuna vincta larvae. Sources of naturally occurring cues for inducing settlement and metamorphosis in Lacuna vincta larvae were investigated to understand further the distribution patterns of this species on macroalgal types. Extension of the work investigated the suitability of various artificial cues for inducing metamorphosis and the effects of larval age and nutritional status of larvae upon latency of response to established inducing cues. Overall, L. pallidula displayed greater variation in traits and was more sensitive to environmental change than L. vincta. This finding is discussed in light of the two species larval strategy

    Impact of case management by advanced practice nurses in primary care on unplanned hospital admissions: a controlled intervention study

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    <p>Abstract</p> <p>Background</p> <p>Increasing unplanned hospital admissions disrupt planned health care, lead to additional morbidity and are expensive. A recent review found only weak evidence for case management preventing unplanned admissions, yet case management of older people is being implemented widely in the UK. We aimed to study the effect of advanced practice nurse case management on unplanned medical and geriatric hospital admission rates in patients 50 years and over, and on admission risk in a 'higher risk' sub-group of patients in the UK.</p> <p>Methods</p> <p>Case management by advanced practice nurses in NHS primary care practices in the Swansea Local Health Board area, Wales, UK. We conducted a prospective non-randomized controlled intervention study comparing unplanned medical and geriatric patient admissions between five intervention and thirty non-intervention practices during a pre-intervention year and an intervention year.</p> <p>Results</p> <p>For all lengths of stay, comparing intervention (n = 5) with non-intervention practices (n = 30) from pre-intervention to intervention year, we found that the unplanned medical and geriatric admission rate was significantly lower in the intervention group – adjusted relative risk of 0.909; relative risk reduction 9.1% (95% credible limit 0.840 to 0.984, p = 0.018); absolute risk reduction 0.99 admissions per 100 patients (95% credible limit 0.17 to 1.86, p = 0.018). For lengths of stay of one night or more we observed a stronger effect – adjusted relative risk 0.896; relative risk reduction 10.41% (95%, credible limit 0.820 to 0.979, p = 0.015). Most of the rate reduction was due to a reduction in the number of new admissions but much less so for admissions of lengths of stay of at least one night, compared to all lengths of stay. We did not find a statistically significant effect on re-admission or multiple re-admission rates in 'higher risk' patients previously admitted one or more times – adjusted relative risk of further multiple admissions per previously admitted patient 0.908 (95% credible limit 0.765, 1.077); relative risk reduction 9.3%; adjusted relative risk of total admissions per multiple admitter 0.995 (95% credible limit 0.940, 1.053) relative risk reduction 0.6%.</p> <p>Conclusion</p> <p>Although this study reports a reduction in unplanned admission rates in the intervention practices, this appears to be only in part directly due to nurse case management: most of the reduction did not occur in multipe admitters whom were case managed. Further research is needed to explain this finding, to elucidate how best to target the attention of case managers and to examine the complexity of potential outcomes in terms of the nature and necessity of admissions and most suitable lengths-of-stay in terms of acute care or rehabilittion need.</p

    Postoperative continuous positive airway pressure to prevent pneumonia, re-intubation, and death after major abdominal surgery (PRISM): a multicentre, open-label, randomised, phase 3 trial

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    Background: Respiratory complications are an important cause of postoperative morbidity. We aimed to investigate whether continuous positive airway pressure (CPAP) administered immediately after major abdominal surgery could prevent postoperative morbidity. Methods: PRISM was an open-label, randomised, phase 3 trial done at 70 hospitals across six countries. Patients aged 50 years or older who were undergoing elective major open abdominal surgery were randomly assigned (1:1) to receive CPAP within 4 h of the end of surgery or usual postoperative care. Patients were randomly assigned using a computer-generated minimisation algorithm with inbuilt concealment. The primary outcome was a composite of pneumonia, endotracheal re-intubation, or death within 30 days after randomisation, assessed in the intention-to-treat population. Safety was assessed in all patients who received CPAP. The trial is registered with the ISRCTN registry, ISRCTN56012545. Findings: Between Feb 8, 2016, and Nov 11, 2019, 4806 patients were randomly assigned (2405 to the CPAP group and 2401 to the usual care group), of whom 4793 were included in the primary analysis (2396 in the CPAP group and 2397 in the usual care group). 195 (8\ub71%) of 2396 patients in the CPAP group and 197 (8\ub72%) of 2397 patients in the usual care group met the composite primary outcome (adjusted odds ratio 1\ub701 [95% CI 0\ub781-1\ub724]; p=0\ub795). 200 (8\ub79%) of 2241 patients in the CPAP group had adverse events. The most common adverse events were claustrophobia (78 [3\ub75%] of 2241 patients), oronasal dryness (43 [1\ub79%]), excessive air leak (36 [1\ub76%]), vomiting (26 [1\ub72%]), and pain (24 [1\ub71%]). There were two serious adverse events: one patient had significant hearing loss and one patient had obstruction of their venous catheter caused by a CPAP hood, which resulted in transient haemodynamic instability. Interpretation: In this large clinical effectiveness trial, CPAP did not reduce the incidence of pneumonia, endotracheal re-intubation, or death after major abdominal surgery. Although CPAP has an important role in the treatment of respiratory failure after surgery, routine use of prophylactic post-operative CPAP is not recommended

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