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: β = -0.14, 95% CI -0.36, 0.07; 1 SD below: β = -0.23, 95% CI -0.39, -0.06; mean: β = -0.39, 95% CI -0.50, -0.29; 1 SD above: β = -0.56, 95% CI -0.70, -0.42; 1.5 SD above: β = -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: β = -0.20, 95% CI -0.35, -0.05; 1.5 SD above: β = -0.30, 95% CI -0.49, -0.11); at lower levels of burnout, older age was associated with improvements in this (1 SD below: β = 0.19, 95% CI 0.03, 0.35; 1.5 SD below: β = 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.

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.

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.

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.

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.

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.

Acute hypoxemic respiratory failure in children: case mix and the utility of respiratory severity indices

OBJECTIVE

Acute hypoxemic respiratory failure (AHRF) is a common reason for emergency pediatric intensive care. An objective assessment of disease severity from acute physiological parameters would be of value in clinical practice and in the design of clinical trials. We hypothesised that there was a difference in the best early respiratory indices in those who died compared with those who survived.

DESIGN

A prospective observational study of 118 consecutive AHRF admissions with data analysis incorporating all blood gases.

SETTING

A pediatric intensive care unit in a national children's hospital.

INTERVENTIONS

None.

RESULTS

Mortality was 26/118, 22% (95 % confidence interval 18-26%). There were no significant differences in the best alveolar-arterial oxygen tension gradient (A-aDO2, torr), oxygenation index (OI), ventilation index (VI), or PaO2/FIO2 during the first 2 days of intensive care between the survivors and non-survivors. Only the mean airway pressure (MAP, cm H2O) used for supportive care was significantly different on days 0 and 1 (p < 0.05) with higher pressure being used in non-survivors. Multiple logistic regression analysis did not identify any gas exchange or ventilator parameter independently associated with mortality. Rather, all deaths were associated with coincident pathology or multi-organ system failure, or perceived treatment futility due to pre-existing diagnoses instead of unsupportable respiratory failure. When using previously published predictors of outcome (VI > 40 and OI > 40; A-aDO2 > 450 for 24 h; A-aDO2 > 470 or MAP > 23; or A-aDO2 > 420) the risk of mortality was overestimated significantly in the current population.

CONCLUSION

The original hypothesis was refuted. It appears that the outcome of AHRF in present day pediatric critical care is principally related to the severity of associated pathology and now no longer solely to the severity of respiratory failure. Further studies in larger series are needed to confirm these findings.

Investigation of platelet-neutrophil interactions in whole blood by flow cytometry

Evidence is increasing that platelets can initiate and propagate inflammatory processes by interacting with leucocytes and the vascular endothelium. Platelets have been shown to bind to neutrophils, existing as platelet/neutrophil complexes (PNC) within the circulation. We describe a simple flow cytometric method for assessing and investigating platelet interactions with neutrophils in small volumes of whole blood. Twenty-five percent (sd 6%) of circulating neutrophils from healthy adults were associated with platelets. Formation of these platelet-neutrophil complexes was CD62P (P-selectin) and divalent cation dependent. Platelet activation (with ADP or thrombin) caused a rapid and sustained rise in %PNC which differed from the pattern of free platelet activation as assessed by CD62P expression. F-met-leu-phe induced neutrophil activation but did not increase the percentage PNC. Platelet activation also caused increased neutrophil CD11b/CD18 expression which was most marked on neutrophils complexed with platelets. This straightforward technique is simple, reproducible, and allows assessment of platelet-neutrophil interactions and activation of neutrophils. It may also provide a method for estimating platelet activation in whole blood.

Repair of an osteochondral tumor of the talus utilizing a fresh-frozen cadaveric graft

A case involving a benign osteochondral tumor of the talar dome is presented. Graft considerations are reviewed and some of their specific characteristics are highlighted. Selection of a fresh-frozen cadaveric graft in this case was based on the goal of maintaining articular congruity in the ankle joint. The authors' experience demonstrated that normal joint function can be preserved with this type of graft.

Maturation of porcine tracheal cholinergic and inhibitory non-adrenergic, non-cholinergic innervation

It is known that both excitatory cholinergic neural activity and nitric oxide (NO) release from inhibitory non-adrenergic, non-cholinergic (iNANC) nerves are important determinants of adult human airway smooth muscle tone. However, the level of cholinergic and iNANC activity in the newborn is unknown. Therefore, isolated trachealis muscle strips were obtained from neonatal, 10-day-old, and adult pigs. To quantify cholinergic nerve activity, isometric contractions were elicited by stimulating the nicotinic receptors of the cholinergic intramural ganglia with dimethyl-phenyl-piperazinium (DMPP). After ganglionic blockade with hexamethonium, the post-ganglionic cholinergic nerves were subjected to electrical field stimulation (EFS). To assess whether DMPP and EFS were also stimulating nitric oxide release from iNANC nerves, the stimulations were repeated after NO-synthase inhibition with 3 x 10(-5) M NG-monomethyl-L-arginine acetate (LNMMA). All responses were expressed as a percentage of maximal response to 10(-4) M acetylcholine. Although no significant age-related differences in the contractile responses to DMPP were demonstrated between the three age groups, the EFS responses were significantly different. At EFS frequencies of 1 and 2 Hz the responses of all three groups were different (P < 0.05, unpaired t-test). At frequencies of 0.125 and 0.5 Hz the contractile responses in the neonatal and 10-day-old groups were less than in the adult animal tissues (P < 0.05, unpaired t-test). At 4 Hz and above, the responses of the 10-day-old and adult groups became greater than the neonatal (P < 0.05, unpaired t-test). LNMMA did not significantly increase the contractile responses to DMPP at any age. Only in the neonatal rat and 10-day-old groups was a significant increase of the EFS frequency responses by LNMMA demonstrated (140.4 +/- 38.2% and 144.2 +/- 41.2%, respectively, at 0.5 Hz, ANOVA, P < 0.001). In conclusion, the DMPP responses suggest that the neonatal porcine cholinergic innervation is mature at birth. This contrasts with a frequency-dependent increase in EFS responses from birth. This may be due in part to a relative increase in iNANC modulation of post-ganglionic cholinergic activity at birth. This mechanism is not responsible for the increase in higher EFS frequency responses with post-natal maturation. Inhibitory iNANC activity may serve a protective role in the newborn, given the reported hyper-responsiveness of airway smooth muscle, small airway caliber, and high chest wall compliance at this age.

Rapid inhalation induction in children: 8% sevoflurane compared with 5% halothane

Sevoflurane has a lower blood-gas solubility and a less pungent odour than halothane; this may allow more rapid induction of anaesthesia. In a randomized, blinded study, we compared the induction characteristics of maximum initial inspired concentration of 8% sevoflurane and 5% halothane using conventional vaporizers in children aged 3 months to 3 years. There was no statistically significant difference in induction times between the two groups: mean times to loss of consciousness were 1 min 12 s (SD 18 s, range 40 s-1 min 44 s) for sevoflurane and 1 min 16 s (SD 17 s, range 50 s-1 min 52 s) for halothane, although these times were shorter than in previous studies using a gradual increase in vapour concentration. A small number of complications were noted in both groups, although none interfered with induction of anaesthesia. Struggling scores were lower in the sevoflurane group than in the halothane group (chi-square for trends = 6.34, P < 0.02). A significant number (11 of 15) of parents of children in the sevoflurane group who had previous experience of halothane induction preferred sevoflurane (chi-square for trends = 4.03, P < 0.05). We conclude that with this technique, induction was rapid with both sevoflurane and halothane. Our assessment of patient struggling and parents' perceptions suggests that induction with sevoflurane was more pleasant than with halothane.

Impact of insect root herbivory on the growth and nitrogen and carbon contents of white clover (Trifolium repens) seedlings

The impact of root herbivory by larvae of the weevil Sitona flavescens (Marsh.) on the growth and carbon and nitrogen economies of seedlings of white clover (Trifolium repens L.) and the nature and extent of nitrogenous compounds found in the root exudates taken from the rhizosphere were investigated. The seedlings were grown in sand culture in a system of microlysimeters that enabled sequential sampling of root exudates. Weevil infestation significantly reduced foliar biomass and total N and C contents and impaired N-fixation. The C:N ratios of the infested plants were significantly increased compared with those of uninfested seedlings. The most abundant amino acids in the exudates were aspartic acid and serine. Keywords: nitrogen fixation, Sitona spp., root exudates, white clover.

A new critical incident monitor for use with the paediatric T-piece. In vitro evaluation and clinical experience with the Magtrak Infanta Electronic Respirometer

In vitro studies and clinical evaluation suggest that the Magtrak Infanta Electronic respirometer provides a useful additional critical incident monitor for use with the paediatric T-piece. During ventilation with the Nuffield 200 ventilator and Newton valve it provides early warning of leaks or disconnections in the breathing system, airway obstruction and reduction in fresh gas flow. Some of these events may not be detected by conventional monitors.

A comparison of the induction characteristics of sevoflurane and halothane in children

The induction characteristics of sevoflurane and halothane were compared in 81 children aged 6 months to 6 years. The mean time taken to achieve loss of eyelash reflex was significantly shorter with sevoflurane than with halothane (sevoflurane, mean time (SD) 1 min 41 s (35 s), halothane, mean time (SD) 2 min 17 s (43 s), t = 4.11, p = < 0.01). The mean time taken to complete induction (to achieve steady spontaneous ventilation and small pupils with central gaze) was also shorter in children induced with sevoflurane (sevoflurane, mean time (SD) 3 min 58 s (1 min 8 s), halothane, mean time (SD) 4 min 50 s, (1 min 27 s), t = 2.29, p = 0.027). Effects on heart rate, blood pressure and oxygen saturation during induction were similar for both agents. There were no major complications during induction with either halothane or sevoflurane.

A comparison of the recovery characteristics of sevoflurane and halothane in children

The recovery characteristics of sevoflurane and halothane anaesthesia were compared in 40 children aged 6 months to 6 years undergoing day case surgery. The mean time taken to open eyes after surgery had ended was appreciably and significantly shorter after sevoflurane than after halothane (sevoflurane, mean time (SD) 7 min 52 s (5 min 46 s), halothane, mean time (SD) 15 min 50 s (9 min 2 s), t = 3.32, p = 0.002). The time taken to be ready for discharge from the recovery unit to the ward was also significantly shorter after sevoflurane than after halothane (sevoflurane, mean time (SD) 12 min 46 s (4 min 11 s), halothane, mean time (SD) 19 min 13 s (9 min 48 s), t = 2.7, p < 0.01). However, more children were in pain and given analgesia after sevoflurane (p < 0.01) and the mean time to reach the criteria for discharge home was similar in both groups (sevoflurane, mean time (SD) 2 h 9 min (17 min), halothane, mean time (SD) 2 h 4 min (8 min)). There were no major complications in either group.

A comparison of sevoflurance to halothane in paediatric surgical patients: results of a multicentre international study

Induction, emergence and recovery characteristics were compared during sevoflurane or halothane anaesthetic in a large (428) multicentre, international study of children undergoing elective inpatient surgical procedures. Two hundred and fourteen children in each group underwent inhalation induction with nitrous oxide/oxygen and sevoflurane or halothane. Incremental doses of either study drug were added until loss of eyelash reflex was achieved. Steady state concentrations of anaesthesia were maintained until the end of surgery when anaesthetic agents were terminated simultaneously. Time variables were recorded for induction, emergence and the first need for analgesia in the recovery room. In addition, in 86 of the children in both groups, venous blood samples were drawn for plasma fluoride levels during and after surgery. There was a trend toward smoother induction (induction of anaesthesia without coughing, breath holding, excitement laryngospasm, bronchospasm, increased secretion, and vomiting) in the sevoflurane group with faster induction (2.1 min vs 2.9 min, P = 0.037) and rapid emergence times (10.3 min vs 13.9 min, P = 0.003). Among the children given sevoflurane, 2% developed bradycardia compared with 11% in the halothane group. Postoperatively, 46% of the children in the halothane group developed nausea and or vomiting versus 31% in the sevoflurane group (P = 0.002). Two children in the halothane group developed cardiac dysrhythmia and were dropped from the study. In addition, a child in the halothane group developed malignant hyperthermia, received dantrolene, and had an uneventful recovery. Mean maximum inorganic fluoride concentration was 18.3 microM.l-1. The fluoride concentrations peaked within one h of termination of sevoflurane anaesthetic and returned rapidly to baseline within 48 h. This study suggests that sevoflurane may be the drug of choice for the anaesthetic management of children.

Comparison of the pharmacodynamics of ketamine in the isolated neonatal and adult porcine airway

Ketamine inhibits contractions of adult airway smooth muscle by actions both within the smooth muscle cell and the vagal intramural ganglia. Its effects in the neonate are unknown, as physiological changes occur after birth in both of these structures. Isolated trachealis muscle strips from neonatal and adult pigs were contracted selectively by stimulation of the vagal intramural ganglia using dimethyl-phenyl-piperazinium (DMPP), the post-ganglionic vagus nerve using electrical field stimulation (EFS) and the smooth muscle cell itself using acetylcholine (ACh) in the presence of tetrodotoxin. The inhibitory effects of clinical concentrations of ketamine at each site were compared both within and between age groups. At both ages, ketamine 10(-4) mol litre-1 abolished (P < or = 0.001) and ketamine 10(-5) mol litre-1 attenuated (P < or = 0.001) the contractile responses to DMPP at the intramural ganglia. The inhibitory effect of ketamine 10(-4) mol litre-1 on ACh responses at the smooth muscle cell was greater in neonatal preparations (P = 0.025). Furthermore, only neonatal EFS and ACh responses were attenuated by ketamine 10(-5) mol litre-1 (P = 0.04 and P = 0.03). Ketamine 10(-4) mol litre-1 attenuated EFS responses in both age groups (P < or = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative fasting for paediatric anaesthesia

Preoperative fasting was introduced to reduce the risk and severity of aspiration pneumonitis. Adequate time (6h) must still be allowed before operation for solid foods to be emptied from the stomach. However, the overwhelming weight of evidence supports the practice of reducing the duration of the preoperative fluid fast for elective paediatric surgical patients [3, 15]. In children allowed free, clear fluids until 2 h before the scheduled time of anaesthesia, gastric contents and thus the risk of aspiration pneumonitis appears to be similar to those children who have endured a longer fast. Potential benefits of reduced thirst, better perioperative experience, improved compliance and reduced hypoglycaemia may be seen. Patients at risk of GOR and aspiration pneumonitis, including those presenting for emergency surgery, must receive special consideration. As aspiration pneumonitis is so rare, careful reporting of complications potentially related to a reduced fasting period is necessary.

Postal survey of paediatric practice and training among consultant anaesthetists in the UK

A postal survey of previous paediatric anaesthetic training, current paediatric experience and management of an infant pyloromyotomy was undertaken among consultant anaesthetists in the UK. A total of 851 questionnaires were returned, giving a response rate of 31%; 352 (41%) consultants had at least one paediatric list each week, 180 (21%) anaesthetized more than one infant less than 6 months old each month and 373 (44%) had obtained more than 6 months' specialist training. Consultants trained most recently had received significantly longer (P < 0.001) specialist training than their senior colleagues: 558 (66%) consultants dealt with infants requiring a pyloromyotomy, 348 with one or two cases annually. Two-thirds preferred to use an i.v. induction technique and less than half used cricoid pressure. Choice of technique was related to the duration of specialist paediatric training and when it was received, but not to current paediatric anaesthetic experience. The results are discussed in relation to recently published recommendations on paediatric anaesthetic services.

Specialist anaesthetic training and certification process in England

Specialist accreditation in anaesthesia in the United Kingdom currently requires a minimum of six years recognised training after full medical registration. In future, the training programme will become more structured, with more emphasis on regular in-training assessment, and attempts are being made to reduce the overall training period. The Royal College of Anaesthetists has published a proposed plan for structured training and is evaluating the reliability and validity of traditional and newer methods of examination. It is one of the first postgraduate bodies to introduce the Objective Structured Clinical Examination (OSCE) into its examination structure. A more formal programme of Continuing Medical Education is also being considered.

Mechanisms of the relaxant action of ketamine on isolated porcine trachealis muscle

Ketamine is a potent bronchodilator, but its mode of action is unclear. We have studied the effect of ketamine on the peripheral vagus nerve motor pathway of isolated porcine trachealis muscle. Postsynaptic nicotinic cholinergic receptors of the intramural ganglia were stimulated selectively with 1,1-dimethyl-4-phenyl-piperazinium iodide, post-ganglionic nerve fibres with electrical field stimulation (in the presence of hexamethonium) and muscarinic cholinergic receptors with acetylcholine (in the presence of tetrodotoxin). Ketamine 10(-4) mol litre-1 significantly shifted the concentration-response curves of acetylcholine (P < 0.02) and electrical field stimulation (P < 0.001) to the right and abolished the response to 1,1-dimethyl-4-phenyl-piperazinium iodide (P < 0.02). Ketamine also caused a concentration-dependent relaxation of muscle strips precontracted with acetylcholine. This was unaffected by propranolol. Ketamine relaxed muscle strips precontracted with potassium chloride, in the absence and presence of atropine. We conclude that ketamine interacts with the peripheral vagus nerve by decreasing the excitability of the postsynaptic nicotinic receptors of the intramural ganglia, and by affecting the muscarinic receptor, smooth muscle, or both. Beta-2 adrenoceptors are not involved in the mechanism of relaxation.

Aneurysmal bone cyst of the second metatarsal

Aneurysmal bone cyst of the second metatarsal has infrequently been reported in the literature. Its characteristics can mimic various other bone tumors. While radiographic appearance usually typifies this lesion, microscopic evaluation is paramount for a definitive diagnosis. There are various treatment alternatives for this lesion depending on size, the patient's age and radiographic appearance. After evaluating the patient's age and size of lesion in their case study, the authors recommended total excision of the bone cyst with autogenous grafting. The need for rigid external fixation was emphasized. These factors combined to produce satisfactory results in this case study that involved over 2 years of postoperative evaluation.

Respiratory compliance during sedation, anesthesia, and paralysis in infants and young children

Although total respiratory compliance (Crs) has been shown to fall in adults on induction of halothane anesthesia, no successful paired studies have been reported in children. The multiple occlusion technique was used to measure Crs in 17 infants and young children during sedated sleep (CrsS) and shortly after, following induction of halothane anesthesia (CrsA). Crs fell in all but one infant after induction of anesthesia, with a mean fall of 34.7% (range 0-58%). This was accompanied by a reduction in tidal volume and increase in frequency in every case. In 7 of the 17 children, who were to be paralyzed for surgical purposes, Crs was also measured in this anesthetized-paralyzed state. When tidal volume administered during manual ventilation was similar to that observed during measurement of CrsA, Crs during this low-volume ventilation was similar to CrsA. When tidal volume was increased and Crs remeasured, there was a significant increase in every case, with the high-volume Crs within 10% of CrsS in all but one child, in whom there was a 31.4% increase with respect to CrsS. Changes in tidal volume accounted for approximately 50% of the variability in each state. These results demonstrate a highly significant fall in Crs in infants and young children after induction of halothane anesthesia. In addition it appears that this reduction in Crs can be reversed by paralyzing the child and manually ventilating with tidal volumes approximating those seen during sedation.

Assessment of a hygroscopic heat and moisture exchanger for paediatric use

A laboratory study of a widely available heat and moisture exchanger marketed for paediatric use was undertaken. The deadspace, measured by volume displacement, was 12 ml, similar to that of a standard catheter mount for paediatric use. Pressure drop across the device was measured at several different flows in five samples of the device in both the dry and wet state. Calculated resistance proved to be markedly lower when compared with that of other anaesthetic equipment such as tracheal tubes, and with similar humidification devices for paediatric use.

The effect of triclofos sodium sedation on respiratory rate, oxygen saturation, and heart rate in infants and young children

Chloral hydrate is frequently used to sedate infants for lung function testing. While no effect on respiratory function has been demonstrated, a recent study has reported a fall in oxygen saturation (SaO2) following sedation in wheezy infants. This study was designed to assess the effects of the closely related but less gastrically irritant drug triclofos sodium on respiratory rate (RR), heart rate (HR), and SaO2 in infants without cardiopulmonary disease. Paired measurements using respiratory inductance plethysmography and pulse oximetry were obtained in 10 infants (4-19 months of age) during natural and sedated sleep. Following sedation with triclofos, mean RR rose by 1.9 breaths min-1 (95% confidence intervals [Cl] of the mean difference: 0.13-3.7 min-1). Mean heart rate rose by 5.5 beats min-1 (95% Cl: -0.9-11.9 min-1). Mean SaO2 fell by 0.68% (95% Cl -1.8-0.45%). None of these changes are considered to be of clinical importance, and only the change in RR reached statistical significance at the 5% level.

Complications of nasotracheal intubation in neonates, infants and children: a review of 4 years' experience in a children's hospital

A computerized database was set up to study the incidence and outcome of complications of nasotracheal intubation in a paediatric hospital. We studied 2953 intensive care admissions over a 4-yr period. The overall complication rate was 8%. Accidental extubation and tube blockage were the most frequent events, accounting for a mean of 3.5% and 2.6% of the complications per year, respectively. Complications were more common in smaller children and there were differences between fields of intensive care. None of the complications was fatal or resulted in serious sequelae. None of the children in the study showed clinical symptoms of acquired subglottic stenosis before discharge from hospital, and none has been readmitted for this condition subsequently.