Age, burnout and physical and psychological work ability among nurses.

Background: The ageing of the US labour force highlights the need to examine older adults' physical and psychological ability to work, under varying levels of occupational burnout. Aims: To examine how age and burnout interact in predicting physical and psychological work ability. Methods: Using a cohort of actively working nurses, we assessed factors on the Work Ability Index at 12-month follow-up and determined how these were related to age and exhaustion-related burnout at baseline. Results: The study group consisted of 402 nurses aged 25-67 (mean = 41.7). Results indicated age by burnout interactions in which decrements in physical work ability with greater age were observed at all but the lowest level of burnout (1.5 SD below mean: ß = -0.14, 95% CI -0.36, 0.07; 1 SD below: ß = -0.23, 95% CI -0.39, -0.06; mean: ß = -0.39, 95% CI -0.50, -0.29; 1 SD above: ß = -0.56, 95% CI -0.70, -0.42; 1.5 SD above: ß = -0.64, 95% CI -0.83, -0.46). In contrast, we observed decrements in psychological work ability with age at higher levels of burnout only (1 SD above: ß = -0.20, 95% CI -0.35, -0.05; 1.5 SD above: ß = -0.30, 95% CI -0.49, -0.11); at lower levels of burnout, older age was associated with improvements in this (1 SD below: ß = 0.19, 95% CI 0.03, 0.35; 1.5 SD below: ß = 0.29, 95% CI 0.08, 0.50). Conclusions: Findings indicated physical and psychological dimensions of work ability that differed by age and occupational burnout. This emphasizes the need for interventions to reduce burnout and to address age-related strengths and vulnerabilities relating to physical and psychological work ability.

Soil mineral N retention and N(2) O emissions following combined application of (15) N-labelled fertiliser and weed residues.

RATIONALE: The combination of plant residues with inorganic fertiliser-N provides the potential to increase N-use efficiency in agricultural fruit production systems, such as olive orchards. The development of weeds in the inter-canopy area of olive orchards is encouraged as a novel strategy to reduce soil erosion. However, little is known about soil N retention or N(2) O production following the combined application of inorganic-N with the mulched weed residues. METHODS: Emissions of (15) N-N(2) O and soil mineral (15) N retention were measured following combined applications of (15) N-labelled fertiliser and a range of olive crop weed residues to a silty loam soil under controlled conditions. These plant residues differed in their C:N ratios, lignin and polyphenol contents. RESULTS: The magnitude of soil (15) N-NO(3) (-) retention from combining plant residues and fertiliser-N was highly dependent on potential N mineralisation (r = -0.96) and the (lignin + polyphenol)-to-N ratio (r = 0.98) of the residues. Fertiliser-N-derived retention was zero for a legume-based mulch but up to 80% in the treatment containing plant residues with a high (lignin + polyphenol)-to-N ratio. N(2) O emissions increased after the addition of residues, and increased further (up to 128%) following the combined application of inorganic fertiliser and residues. Fertiliser-derived (15) N-N(2) O was <1.4% of the total (14+15) N-N(2) O emission and <0.01% of the applied (15) N-NO(3) (-) . Enhanced N(2) O emissions following the application of residues and the fertiliser-N values were positively correlated with the C:N ratio of the residue. Thus, combining organic- and inorganic-N immobilised a significant proportion of the inorganic N with little increase in N(2) O, especially in low C:N ratio residues. CONCLUSIONS: The results demonstrate that whilst there is potential for N(2) O emissions to be controlled by combining weed residues and inorganic fertilisers, this is not easy to achieve as the magnitude and direction of interactions vary between different species due to their varying substrate qualities.

Gross and net rates of nitrogen mineralisation in soil amended with composted olive mill pomace.

Olive mill pomace is the major waste product in the olive oil industry and composting these by-products for the purpose of recycling nutrients and organic matter is a sound environmental strategy. Yet little is known about the quantity and timing of nitrogen (N) release from composted olive mill pomace. This paper assesses both gross (using the (15)N dilution technique) and net (aerobic incubation) nitrogen (N) mineralisation and N(2)O emissions of soil amended with seven commercially available composts of olive mill pomace (COMP). All are currently produced in Andalusia and differ in the proportions of raw materials co-composted with the pomace. The absence of significant differences in net N or gross mineralisation and nitrification in COMP-amended soil compared with a control, except for COMP combined with poultry manure, highlighted the recalcitrant nature of the COMP-N. Applications of COMP are hence unlikely to supply available N in available forms, at least in the short-term. Furthermore, N(2)O emissions from COMP-amended soil were negligible and, therefore, applications in the field should not result in increased N loss through denitrification.

High rates of nitrogen cycling in volcanic soils from Chilean grasslands.

There are over one million hectares of pasture in Chile, and 80% and 50% of the country's milk and meat comes from 72% of this area, situated in the lake region of southern Chile. The soils are volcanic and a major characteristic is that they have very high organic matter (OM) contents with the potential to support plant growth with only moderate levels of added nitrogen (N). To understand better the potential fertility of these soils in order to maximise production and minimise losses of N, we undertook studies using the stable isotope of N ((15)N) to resolve the rates of the main internal N cycling processes in three soils representing the two main volcanic soil types: Osorno and Chiloé (Andisol) and Cudico (Ultisol). We also assessed the longer-term potential of these soils to sustain N release using anaerobic incubation. Gross rates (µg N g(-1) day(-1)) of mineralisation were 27.9, 27.1 and 15.5 and rates of immobilisation were 5.9, 12.0 and 6.3 for Osorno, Chiloé and Cudico, respectively, implying high rates of net mineralisation in these soils. This was confirmed by anaerobic incubation which gave potential seasonal net mineralisation indices of 1225, 1059 and 450 kg N ha(-1) in the top 10 cm soil layers of the three soils. However, plant production may still benefit from added N, as the release of N from organic sources may not be closely synchronised with crop demand. The low rates of nitrification that we found with these acidic soils suggest that the more mobile N (viz. nitrate-N) would be in limited supply and plants would have to compete for the less mobile ammonium-N with the soil microbial biomass. Nitrogen was mineralised in appreciable amounts even down to 60 cm depth, so that leaching could become significant, particularly if the soils were limed, which could enhance nitrification and N mobility through the soil profile.

Evidence for the production of NO and N2O in two contrasting subsoils following the addition of synthetic cattle urine.

Nitrogenous materials can be transferred out of the topsoil, either vertically to a greater depth, or in lateral pathways to surface waters, and they may also become transformed, with the potential of generating environmentally active agents. We measured the production of NO and N(2)O in two contrasting subsoils (70 to 90 cm): one poorly drained and the other freely drained and compared this with the topsoil (0 to 20 cm) of the corresponding soils. The soils were incubated aerobically in jars with subtreatments of either synthetic cattle urine or deionised water and sampled at intervals up to 34 days. (15)N-NO(3)(-) was used to determine the processes responsible for NO and N(2)O production. The headspace was analysed for the concentrations of N(2)O, NO and CO(2) and (15)N enrichment of N(2)O. The soil samples were extracted and analysed for NO(2)(-), NO(3)(-) and NH(4)(+), and the (15)N enrichment of the extracts was measured after conversion into N(2)O and N(2). The study demonstrated the potential for NO, N(2)O and NO(2)(-) to be generated from subsoils in laboratory incubations. Differences in these N dynamics occurred due to subsoil drainage class. In the freely drained subsoil the rates of NO and NO(2)(-) production were higher than those observed for the corresponding topsoil, with mean maximum production rates of 3.5 microg NO(2)(-)-N g(-1) dry soil on day 16 and 0.12 microg NO-N g(-1) dry soil on day 31. The calculated total losses of N(2)O-N as percentages of the applied synthetic urine N were 0.37% (freely drained subsoil), 0.24% (poorly drained subsoil), 0.43% (freely drained topsoil) and 2.09% (poorly drained topsoil). The calculated total losses of NO-N as percentages of the applied synthetic urine N were 1.53% (freely drained subsoil), 0.02% (poorly drained subsoil), 0.25% (freely drained topsoil) and 0.08% (poorly drained topsoil).

The effect of cutting, mulching and applications of farmyard manure on nitrogen fixation in a red clover/grass sward.

In organic farming, maximising the amount of nitrogen (N) which is fixed and retained within the soil is of paramount importance for the yield of the following crop. The aim of this study was to establish the extent to which increased soil fertility, farmyard manure (FYM) applications and/or mulching, could adversely affect fixation. At two sites, situated in the South West (SW) and North East (NE) of England, N(2) fixation was estimated in 'organically' managed red clover/grass plots, both with and without green manure (i.e. surface mulched) and/or the addition of FYM. The FYM was incorporated into the seedbeds at both sites in autumn 2002 at the rate of 170 kg total Nha(-1), as either well-composted (SW site), or not actively-composted (NE site) manures. The same FYM application rate was repeated as top-dressings to both sites in autumn 2003. The plots were cut three or four times each year over two growing seasons. In the first harvest year (2003), incorporation of FYM had beneficial effects of increasing dry matter and N yields significantly at the first cut, but there were no significant differences in subsequent cuts. The same pattern was found in the second harvest year (2004) after the top dressings of FYM, suggesting that most of the N in both types of FYM was in recalcitrant forms. Over the two growing seasons, mulching did not affect red clover/grass dry matter or N yields, but did reduce the proportion of N(2) fixed, by up to 60 kg Nha(-1) when compared with plots from which the clover/grass herbage was cut and removed. Thus, the gain in N from FYM or green manure tended to be offset by a similar reduction in N(2) fixation. These results demonstrate the close association between the availability of soil N and the feed-back system which operates on N(2) fixation by red clover.

Quality in paediatric anaesthesia: a pilot study of interdepartmental peer review.

A pilot to assess a process of interdepartmental peer review of paediatric anaesthetic departments in the United Kingdom was undertaken. Departments were assessed in relation to the standards which should characterise anaesthetic departments throughout the country. Examples of good practice and areas for further development were identified. Peer review visits were conducted by teams which included medical and non-medical members. The importance of the inclusion of lay people in such visits is being increasingly recognised. All of those who participated in the process felt their time had been usefully spent, and they were enthusiastic for the process to continue.

Inflammatory pain and hypersensitivity are selectively reversed by epidural bupivacaine and are developmentally regulated.

BACKGROUND: Low doses of local anesthetics applied to the young rat spinal cord in vitro have been shown to inhibit C-fiber-evoked responses. The aim of this work was to investigate whether such low doses applied epidurally selectively reduce nociceptive responses in vivo and to investigate the influence of postnatal development on such local anesthetic actions. METHODS: Three groups of rat pups aged 3, 10, and 21 days were studied. The threshold of the flexion withdrawal reflex to mechanical stimulation was determined in the hind limb at each age. Inflammatory pain was induced in the right hind limb with 2% carrageenan, causing a reduction in the sensory threshold on that side. The difference in threshold between the two sides represents inflammatory hypersensitivity. The effect of low-dose epidural bupivacaine on sensory thresholds and thus the induced hypersensitivity was also determined for each age group. RESULTS: Inflammatory hypersensitivity was selectively attenuated by very low doses of bupivacaine (concentration range. 0.004-0.0625%), which did not affect the sensory threshold in the contralateral uninflamed limb. This effect was also age-related, with younger rats being more sensitive than older rats. CONCLUSIONS: The effects of epidural bupivacaine in the infant rat are developmentally regulated. Lower doses have a selective analgesic effect that decreases with increasing postnatal age.

Preliminary experience with the Doppler ultrasound guided vascular access needle in paediatric patients.

Percutaneous cannulation of the internal jugular vein (IJV) in infants and children may be technically difficult and can lead to complications. Various techniques exist to achieve successful cannulation and to reduce the rate of complications. We report the use of the Doppler ultrasound guided vascular access needle (the SMART needle) for IJV cannulation in 10 infants and young children (mean age 3.7 months) weighing less than 10 kg (mean weight 5.5 kg) who were to undergo cardiac surgery at Great Ormond Street Hospital for Children. Successful cannulation was achieved in six out of 10 patients with haematoma complicating the procedure in two patients. We believe this is the first reported use of this device for cannulation of the IJV in this patient group.

Circulating platelet-neutrophil complexes represent a subpopulation of activated neutrophils primed for adhesion, phagocytosis and intracellular killing.

Platelets play a prominent role in linking the processes of inflammation, haemostasis and thrombosis. Recent studies have shown that platelets form heterotypic aggregates with leucocytes via platelet CD62P and leucocyte beta2 integrins. These interactions have been observed in vitro in blood taken from healthy volunteers and in clinical conditions in which thrombosis and inflammation are prominent. This study investigated the properties of platelet-neutrophil complexes (PNCs) in anticoagulated whole blood. At rest, neutrophils in PNCs exhibit a significantly more activated adhesion molecule profile than free neutrophils with increased CD11b expression and activation (increased binding of the CD11b/CD18 'activation reporter' monoclonal antibody 24) and decreased CD62L expression. In addition, neutrophils in PNCs phagocytosed significantly more Neisseria meningitidis and produced more toxic oxygen metabolites than free neutrophils. Stimulation with the platelet agonist adenosine diphosphate (ADP) led to further increases in CD11b expression and activation, loss of CD62L as well as increased phagocytosis and toxic oxygen metabolite production throughout the whole neutrophil population. When these experiments were repeated with the CD62P blocking antibody G1 the effects were inhibited to a variable extent, dependent upon the parameter under investigation. These results indicate that both soluble and contact-dependent factors contribute to platelet-mediated neutrophil activation. Platelet neutrophil complexes represent a large subpopulation of neutrophils with a more activated adhesion molecule profile, and a greater capacity for phagocytosis and toxic oxygen metabolite production. This study provides further support for a role for PNCs in both health and disease.

Development of a nurse-led sedation service for paediatric magnetic resonance imaging.

BACKGROUND: Children generally lie still enough for magnetic resonance imaging (MRI) only if they are asleep, either under sedation, which is deeper than conscious sedation, or under anaesthesia. Anaesthesia resources, however, are limited, and non-anaesthetists must use sedation frequently. Demand for MRI has increased and the failure of our sedation regimen led to an impractical demand for anaesthesia and unacceptable waiting times for scanning. We have therefore developed a nurse-led sedation service in a designated unit next to the scanner. This study assessed the safety and efficacy of this approach. METHODS: Children who required MRI were sedated in the unit by designated sedationist nurses, who used an oral drug regimen (according to weight and age from conception: weight <5 kg, 50 mg/kg chloral hydrate; 5-10 kg, 100 mg/kg chloral hydrate; 10-20 kg, 1 mg/kg temazepam plus 0.25 mg/kg droperidol; >20 kg temazepam and droperidol as directed by radiologist, maximum doses 20 mg and 5 mg respectively). Nurses checked patients for their suitability, charted and administered the drugs according to a protocol, and monitored the children throughout the sedation. We prospectively audited failure and complications of sedation. FINDINGS: During the 30 month study, there were 1155 sedations. 61 (5%) were unsuccessful, and there were no adverse events relating to the airway or breathing. After scanning had finished all children, in response to gently pinching the nose, could open their mouths to maintain their airway. INTERPRETATION: This study suggests that it is possible to have a nurse-led sedation service for MRI of children that is both successful and safe.

Sensory hyperinnervation after neonatal skin wounding: effect of bupivacaine sciatic nerve block.

The response to tissue injury includes sensitization of peripheral nociceptors and central neuronal pathways leading to acute clinical and inflammatory pain. A further response is sprouting of sensory nerve terminals in the region of skin damage. This hyperinnervation response is particularly intense in neonates compared with adults. In this study, we tested the effect of regional nerve block at the time of injury on skin hyperinnervation. Anaesthetized newborn rat pups were treated with percutaneous sciatic nerve block injections of 0.25% bupivacaine 25 microliters followed by a localized hindpaw skin wound. Cutaneous innervation was studied by image analysis of immunostained skin sections, 7 days after wounding, and sensory thresholds were assessed using von Frey hairs. The results showed that both hyperinnervation and hypersensitivity were not significantly altered by the application of a regional nerve block at the time of injury. This suggests that regional analgesia, used commonly in clinical practice, is unlikely to prevent the hyperinnervation that follows skin wounding.