Cost-Effectiveness of Dementia Prevention Interventions

BACKGROUND

Assessment of cost-effectiveness of interventions to address modifiable risk factors associated with dementia requires estimates of long-term impacts of these interventions which are rarely directly available and must be estimated using a range of assumptions.

OBJECTIVES

To test the cost-effectiveness of dementia prevention measures using a methodology which transparently addresses the many assumptions required to use data from short-term studies, and which readily incorporates sensitivity analyses.

DESIGN

We explore an approach to estimating cost-effective prices which uses aggregate data including estimated lifetime costs of dementia, both financial and quality of life, and incorporates a range of assumptions regarding sustainability of short- term gains and other parameters.

SETTING

The approach is addressed in the context of the theoretical reduction in a range of risk factors, and in the context of a specific small-scale trial of an internet-based intervention augmented with diet and physical activity consultations.

MEASUREMENTS

The principal outcomes were prices per unit of interventions at which interventions were cost-effective or cost-saving.

RESULTS

Taking a societal perspective, a notional intervention reducing a range of dementia risk-factors by 5% was cost-effective at $A460 per person with higher risk groups at $2,148 per person. The on-line program costing $825 per person was cost-effective at $1,850 per person even if program effect diminished by 75% over time.

CONCLUSIONS

Interventions to address risk factors for dementia are likely to be cost-effective if appropriately designed, but confirmation of this conclusion requires longer term follow-up of trials to measure the impact and sustainability of short-term gains.

Magnetic conjugated polymer nanoparticles doped with a europium complex for biomedical imaging

Self-assembling conjugated polymer nanoparticles containing PVK and PLGA-PEG as a matrix polymer were doped with both a luminescent rare-earth complex and magnetic nanoparticles (SPIONs), giving rise to materials that are both luminescent and magnetic.

Nontuberculous mycobacteria in gastrostomy fed patients with cystic fibrosis

Multi-drug resistant Mycobacterium abscessus complex (MABSC) is a form of Nontuberculous mycobacteria (NTM) of special, international concern in Cystic Fibrosis (CF). We hypothesised that gastric juice and percutaneous endoscopic gastrostomy (PEG) feeding devices might yield MABSC isolates. Gastric juice and sputa from sixteen adult PEG fed CF patients and five replaced PEG tubes were studied. Bacterial and fungal isolates were cultured. Mycobacterium were identified by rpoB, sodA and hsp65 gene sequencing and strain typed using variable number tandem repeat. Bacteria and/or fungi grew from all gastric juice, sputa and PEG samples. MABSC were detected in 7 patients. Five had MABSC in their sputum. Two had an identical MABSC strain in their sputum and gastric juice and one had the same strain isolated from their PEG tube and sputum. Two patients who were sputum sample negative had MABSC isolated in their gastric juice or PEG tube. MABSC were therefore identified for the first time from a gastric sample in a minority of patients. We conclude that gastric juice and PEG-tubes may be a potential source of MABSC isolates in CF patients, and these findings warrant further study.

A review of a pleural service

This paper reviews the organisation and outcomes of a pleural service, specifically geared towards the management of malignant pleural effusions, in a district general hospital in the north east of England. We summarise the evidence behind local anaesthetic thoracoscopy and indwelling pleural catheters. We then summarise the review of our service, including a discussion around complications.

Evidence against solar influence on nuclear decay constants

The hypothesis that proximity to the Sun causes variation of decay constants at permille level has been tested and disproved. Repeated activity measurements of mono-radionuclide sources were performed over periods from 200 days up to four decades at 14 laboratories across the globe. Residuals from the exponential nuclear decay curves were inspected for annual oscillations. Systematic deviations from a purely exponential decay curve differ from one data set to another and are attributable to instabilities in the instrumentation and measurement conditions. The most stable activity measurements of alpha, beta-minus, electron capture, and beta-plus decaying sources set an upper limit of 0.0006% to 0.008% to the amplitude of annual oscillations in the decay rate. Oscillations in phase with Earth's orbital distance to the Sun could not be observed within a 10^-6 to 10^-5 range of precision. There are also no apparent modulations over periods of weeks or months. Consequently, there is no indication of a natural impediment against sub-permille accuracy in half-life determinations, renormalisation of activity to a distant reference date, application of nuclear dating for archaeology, geo- and cosmochronology, nor in establishing the SI unit becquerel and seeking international equivalence of activity standards.

Microbiological profiles of sputum and gastric juice aspirates in Cystic Fibrosis patients

Gastro-Oesophageal Reflux (GOR) is a key problem in Cystic Fibrosis (CF), but the relationship between lung and gastric microbiomes is not well understood. We hypothesised that CF gastric and lung microbiomes are related. Gastric and sputum cultures were obtained from fifteen CF patients receiving percutaneous endoscopic gastrostomy feeding. Non-CF gastric juice data was obtained through endoscopy from 14 patients without lung disease. Bacterial and fungal isolates were identified by culture. Molecular bacterial profiling used next generation sequencing (NGS) of the 16S rRNA gene. Cultures grew bacteria and/or fungi in all CF gastric juice and sputa and in 9/14 non-CF gastric juices. Pseudomonas aeruginosa(Pa) was present in CF sputum in 11 patients, 4 had identical Pa strains in the stomach. NGS data from non-CF gastric juice samples were significantly more diverse compared to CF samples. NGS showed CF gastric juice had markedly lower abundance of normal gut bacteria; Bacteroides and Faecalibacterium, but increased Pseudomonas compared with non-CF. Multivariate partial least squares discriminant analysis demonstrated similar bacterial profiles of CF sputum and gastric juice samples, which were distinct from non-CF gastric juice. We provide novel evidence suggesting the existence of an aerodigestive microbiome in CF, which may have clinical relevance.

Red-emitting protein-coated conjugated polymer nanoparticles

Red emitting materials are desirable in biology due to the transparency of certain biological tissues at these wavelengths.

Magnetospherically driven optical and radio aurorae at the end of the stellar main sequence

Aurorae are detected from all the magnetized planets in our Solar System, including Earth. They are powered by magnetospheric current systems that lead to the precipitation of energetic electrons into the high-latitude regions of the upper atmosphere. In the case of the gas-giant planets, these aurorae include highly polarized radio emission at kilohertz and megahertz frequencies produced by the precipitating electrons, as well as continuum and line emission in the infrared, optical, ultraviolet and X-ray parts of the spectrum, associated with the collisional excitation and heating of the hydrogen-dominated atmosphere. Here we report simultaneous radio and optical spectroscopic observations of an object at the end of the stellar main sequence, located right at the boundary between stars and brown dwarfs, from which we have detected radio and optical auroral emissions both powered by magnetospheric currents. Whereas the magnetic activity of stars like our Sun is powered by processes that occur in their lower atmospheres, these aurorae are powered by processes originating much further out in the magnetosphere of the dwarf star that couple energy into the lower atmosphere. The dissipated power is at least four orders of magnitude larger than what is produced in the Jovian magnetosphere, revealing aurorae to be a potentially ubiquitous signature of large-scale magnetospheres that can scale to luminosities far greater than those observed in our Solar System. These magnetospheric current systems may also play a part in powering some of the weather phenomena reported on brown dwarfs.

Employment in adults with cystic fibrosis

BACKGROUND

Chronic ill-health may significantly impact on an individual's ability to work. This not only relates to disease severity but also to psychosocial factors such as illness perception and coping strategies.

AIMS

To explore the factors associated with employment status in adults with cystic fibrosis (CF).

METHODS

Subjects recruited from adult CF clinics in Aberdeen, Birmingham and Newcastle completed questionnaires assessing health-related quality of life (HRQoL), workplace productivity (presenteeism) and employment. Clinical data indicative of disease severity were also recorded.

RESULTS

A total of 254 subjects were recruited, 41 from Aberdeen, 63 from Birmingham and 150 from Newcastle. Sixty-five per cent of subjects were in employment or education. If employed/self-employed, median hours worked was 37.3h/week. Forty per cent reported stopping a job due to CF; 47% felt CF had affected career choice and 24% changed duties because of CF. Ten per cent had taken a pay cut and 23% reported workplace discrimination due to CF. Multivariate modelling demonstrated that employment status was independently associated with educational attainment, centre and the HRQoL domains of role and health perception and is independent of clinical parameters of disease severity.

CONCLUSIONS

Adults with CF reported that CF impacted on their ability to work. Employment appeared to be most strongly associated with educational attainment, locality and HRQoL domains and not clinical parameters of severity. Specific guidance is needed for both adults with CF and potential employers, with appropriate targeted interventions aimed at improving health perceptions and coping strategies.

The impact of dietary calcium intake and vitamin D status on the effects of zoledronate

We investigated whether baseline dietary calcium intake or vitamin D status modified the effects of zoledronate. Neither variable influenced the effect of zoledronate on bone mineral density, bone turnover, or risk of acute phase reaction, suggesting that co-administration of calcium and vitamin D supplements with zoledronate may not always be necessary.

INTRODUCTION

Calcium and vitamin D supplements are often co-administered with bisphosphonates, but it is unclear whether they are necessary for therapeutic efficacy or minimizing side effects of bisphosphonates. We investigated whether baseline dietary calcium intake or vitamin D status modified the effect of zoledronate on bone mineral density (BMD) or bone turnover at 1 year, or the risk of acute phase reactions (APR).

METHODS

Data were pooled from two trials of zoledronate in postmenopausal women without vitamin D deficiency in which calcium and vitamin D were not routinely administered. The cohort (zoledronate n = 154, placebo n = 68) was divided into subgroups by baseline dietary calcium intake (<800 vs. ≥800 mg/day) and vitamin D status [25-hydroxyvitamin D (25OHD) <50 vs. ≥50 nmol/L, and <75 nmol/L vs. ≥75 nmol/L] and treatment × subgroup interactions tested.

RESULTS

There were 52, 86, and 36 % of the zoledronate group and 64, 94, and 46 % of the placebo group that had dietary calcium intake ≥800 mg/day, 25OHD ≥50 nmol/L, and 25OHD ≥75 nmol/L, respectively. There were no significant interactions between treatment and either baseline dietary calcium or baseline vitamin D status for lumbar spine BMD, total hip BMD, the bone turnover markers P1NP and β-CTx, or the risk of an APR. There was also no three-way interaction between baseline dietary calcium intake, baseline vitamin D status, and treatment for any of these variables.

CONCLUSIONS

Baseline dietary calcium intake and vitamin D status did not alter the effects of zoledronate, suggesting that co-administration of calcium and vitamin D with zoledronate may not be necessary for individuals not at risk of marked vitamin D deficiency.

Pertussis outbreak in northwest Ireland, January – June 2010

We report a community pertussis outbreak that occurred in a small town located in the northwest of Ireland. Epidemiological investigations suggest that waning immunity and the absence of a booster dose during the second year of life could have contributed to the outbreak. The report also highlights the need to reinforce the surveillance of pertussis in Ireland and especially to improve the clinical and laboratory diagnosis of cases.

Pertussis outbreak in northwest Ireland, January - June 2010

We report a community pertussis outbreak that occurred in a small town located in the northwest of Ireland. Epidemiological investigations suggest that waning immunity and the absence of a booster dose during the second year of life could have contributed to the outbreak. The report also highlights the need to reinforce the surveillance of pertussis in Ireland and especially to improve the clinical and laboratory diagnosis of cases.

Ionic currents in intimal cultured synoviocytes from the rabbit

Hyaluronan, a joint lubricant and regulator of synovial fluid content, is secreted by fibroblast-like synoviocytes lining the joint cavity, and secretion is greatly stimulated by Ca²⁺-dependent protein kinase C. This study aimed to define synoviocyte membrane currents and channels that may influence synoviocyte Ca²⁺ dynamics. Resting membrane potential ranged from −30 mV to −66 mV (mean −45 ± 8.60 mV, n = 40). Input resistance ranged from 0.54 GΩ to 2.6 GΩ (mean 1.28 ± 0.57 GΩ; ν = 33). Cell capacitance averaged 97.97 ± 5.93 pF. Voltage clamp using C^s+ pipette solution yielded a transient inward current that disappeared in Ca²⁺-free solutions and was blocked by 1 μM nifedipine, indicating an L-type calcium current. The current was increased fourfold by the calcium channel activator FPL 64176 (300 nM). Using K⁺ pipette solution, depolarizing steps positive to −40 mV evoked an outward current that showed kinetics and voltage dependence of activation and inactivation typical of the delayed rectifier potassium current. This was blocked by the nonspecific delayed rectifier blocker 4-aminopyridine. The synoviocytes expressed mRNA for four Kv1 subtypes (Kv1.1, Kv1.4, Kv1.5, and Kv1.6). Correolide (1 μM), margatoxin (100 nM), and α-dendrotoxin block these Kv1 subtypes, and all of these drugs significantly reduced synoviocyte outward current. The current was blocked most effectively by 50 nM κ-dendrotoxin, which is specific for channels containing a Kv1.1 subunit, indicating that Kv1.1 is critical, either as a homomultimeric channel or as a component of a heteromultimeric Kv1 channel. When 50 nM κ-dendrotoxin was added to current-clamped synoviocytes, the cells depolarized by >20 mV and this was accompanied by an increase in intracellular calcium concentration. Similarly, depolarization of the cells with high external potassium solution caused an increase in intracellular calcium, and this effect was greatly reduced by 1 μM nifedipine. In conclusion, fibroblast-like synoviocytes cultured from the inner synovium of the rabbit exhibit voltage-dependent inward and outward currents, including Ca²⁺ currents. They thus express ion channels regulating membrane Ca²⁺ permeability and electrochemical gradient. Since Ca²⁺-dependent kinases are major regulators of synovial hyaluronan secretion, the synoviocyte ion channels are likely to be important in the regulation of hyaluronan secretion.

Selective modulation of ligand-gated P2X purinoceptor channels by acute hypoxia is mediated by reactive oxygen species

Purinergic excitatory synapses use ATP to mediate fast synaptic transmission via activation of P2X receptor cation channels, and this response can be altered by acute hypoxia. This study examined the effect of acute hypoxia on cloned homo- and heteromeric P2X2 and P2X3 receptors expressed in human embryonic kidney 293 cells. In cells expressing homomeric P2X2 receptors, perfusion of 5 microM ATP (EC25) induced an inward whole-cell current that showed little desensitization during repeated exposures under continuously normoxic conditions. Exposure to a hypoxic ATP solution (pO2, 25-40 mm Hg) significantly reduced the whole-cell current to 49% of normoxic control. This hypoxic inhibition of P2X2-mediated inward current was maintained across all potentials when a voltage-step protocol was applied. In contrast, currents mediated by homomeric P2X3 receptors or heteromeric P2X(2/3) receptors were insensitive to an acute hypoxic challenge. One mechanism whereby hypoxia may modulate P2X2 channels is via the production of reactive oxygen species (ROS). H2O2 (1.8 mM) reversibly reduced homomeric P2X2 whole-cell currents to 38% of control. Furthermore, H2O2 attenuated the effect of hypoxia on homomeric P2X2 whole-cell currents. Inhibitors of the mitochondrial electron transport chain that reduce (rotenone and myxothiazol) or increase (antimycin A) the production of ROS altered the magnitude of P2X2-mediated currents. In summary, this is the first report indicating that acute hypoxia is able to regulate the activity of any ligand-gated ion channel. Furthermore, our data show that acute hypoxia selectively modulates the P2X2 receptor and that the response of P2X2 receptor subunits to hypoxia is mediated through the mitochondrial production of ROS.

Treatment pathways, resource use and costs in the management of small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) represents about 20% of primary lung tumours and the costs associated with the management of SCLC can be significant. The main objective of this study was to obtain information on current patterns of care and associated resource use and costs for patients with SCLC from initial diagnosis and treatment phase, throughout disease progression and terminal care.

METHODS

A 4 year retrospective patient chart analysis (1994-7) was conducted on a consecutive series of 109 patients diagnosed with SCLC in two Newcastle hospitals. For this consecutive series of patients all details about care received including tests and procedures, treatment, and medication from diagnosis till death were recorded. Pathways of care and forms were designed to enable resource use to be captured for different disease phases. Unit costs were determined from a variety of sources including the Newcastle Hospitals NHS Trust Finance Department and the British National Formulary.

RESULTS

The average total cost per patient calculated for the full cohort of 109 patients was pound 11,556. Initial treatment was the most resource use intensive constituting 48.2% of the total cost. The major cost element throughout all disease phases was hospitalisation. Twenty eight percent of the total costs of care occur after recurrence of the disease until death, of which 73% are generated by terminal care.

CONCLUSION

The results of this retrospective medical chart analysis show that the costs of care of SCLC are considerable, although the variability between patients in terms of the type and quantity of resource use is very high. Analyses such as this provide a useful insight into resources used in actual clinical practice.

Pigeon fanciers' lung: effects of smoking on serum and salivary antibody responses to pigeon antigens

A reduced prevalence of pigeon fanciers' lung has been reported in pigeon breeders who smoke cigarettes. Serum and salivary antibodies to pigeon intestinal mucin and pigeon serum proteins were investigated in 227 pigeon fanciers, subdivided according to smoking habit and clinical status. Smokers had a lower incidence of precipitating antibodies to pigeon antigens and lower titres of serum IgG and IgA antibodies to mucin and to pigeon serum proteins in ELISA compared with non-smokers and ex-smokers. In contrast, IgG antibody titres to tetanus toxoid were similar in smoking and non-smoking groups. In contrast to serum antibodies, salivary IgA antibody titres to pigeon antigens were similar in smokers and non- or ex-smokers. Approximately one third of the smokers reported symptoms consistent with pigeon fanciers' lung but did not have precipitating antibodies. Only some individuals with precipitating antibodies had disease symptoms, and IgG antibody titres in these individuals were not significantly higher than in many asymptomatic individuals. Salivary IgA titres against pigeon mucin were significantly higher in asymptomatic individuals, consistent with a protective role for these antibodies. The results confirm that smoking is associated with a decreased serum antibody response to inhaled pigeon antigens, affecting IgG1, IgG2 and IgA responses, but this impairment does not extend to salivary IgA or to antibody responses to a parenterally administered protein antigen. The fact that responses to pigeon serum proteins and to pigeon intestinal mucin were similarly affected suggests that cigarette smoking depresses both T-independent and T-dependent responses to inhaled antigens.

Oxygen desaturation during sleep and exercise in patients with severe chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) have varying degrees of arterial oxyhaemoglobin desaturation during sleep, which have been shown to correlate with awake oxygen levels. We wished to ascertain if exercise desaturation was a better predictor of nocturnal oxygen desaturation than daytime blood gases. We studied 25 COPD patients with PaO2 < 10 kPa (mean = 8.6 kPa), 12 of whom were normocapnic (PaCO2 < or = 6 kPa, Group A), and 13 of whom were hypercapnic (PaCO2 > 6 kPa, Group B), by means of overnight oximetry and maximum treadmill exercise testing. The overall group desaturated significantly more during sleep than exercise [12.9 +/- 10.5 fall in nocturnal oxygen saturation (SaO2) vs. 4.5 +/- 3.7, P < 0.01]. Group B had a lower minimum SaO2 during sleep than Group A (74.3 +/- 13.4 vs. 84.6 +/- 5.8, P < 0.05), despite very similar pre-sleep SaO2 (91.9 +/- 3.2 vs. 92.8 +/- 2.9, P = n.s.). Awake SaO2 correlated well with both mean values (r = 0.7, P < 0.001), and minimum sleep SaO2 (r = 0.44, P < 0.05), but not with the fall in sleep SaO2 (r = 0.21, P = n.s.). Minimum sleep and exercise SaO2 were also significantly correlated (r = 0.44, P < 0.05), but the fall in SaO2 during sleep and exercise was not (P = n.s.). We conclude that exercise studies add no extra information to awake blood gas analysis in predicting the likelihood of nocturnal oxygen desaturation in patients with COPD.

Reversible hypercapnia in acute exacerbations of chronic obstructive pulmonary disease (COPD)

We prospectively studied emergency hospitalizations due to acute exacerbations of chronic obstructive pulmonary disease (COPD) among 74 hypercapnic patients, in order to determine factors which predict reversal to normocapnia as a result of therapy. Clinical, arterial blood gas and pulmonary function data on presentation were compared to predischarge values among those 58 patients who survived the admission. Patients were divided into those who reverted to normocapnia (reversible, 40% of surviving patients), and those who remained hypercapnic (chronic, 60% of surviving patients). Reversible patients had higher admission arterial oxygen tension (PaO2) levels than those with chronic hypercapnia (6.4 +/- 1.3 kPa (mean +/- SD), as compared to 5.7 +/- 1.1 kPa) better pulmonary function (forced expiratory volume in one second (FEV1) 35 +/- 16% predicted, as compared to 26 +/- 7.9), and a lower prevalence of cor pulmonale (30% as compared to 63% of patients). No admission variable(s) distinguished individual patients as reversible or chronic hypercapnic, and, in particular, admission arterial carbon dioxide tension (PaCO2) and pH levels were similar in both groups. Furthermore, there were no differences between survivors and those 16 patients who died during the admission, apart from a higher urea level among those who died. These findings suggest that reversible patients have milder underlying disease than those with chronic hypercapnia. Our data establish the high prevalence of reversible hypercapnia among patients hospitalized with exacerbations of COPD, and, furthermore, indicate that patients who are normocapnic in the stable state can develop similar levels of hypercapnia during exacerbations as those with chronic hypercapnia.

Reversible hypercapnia in acute exacerbations of chronic obstructive pulmonary disease (COPD)

We prospectively studied emergency hospitalizations due to acute exacerbations of chronic obstructive pulmonary disease (COPD) among 74 hypercapnic patients, in order to determine factors which predict reversal to normocapnia as a result of therapy. Clinical, arterial blood gas and pulmonary function data on presentation were compared to predischarge values among those 58 patients who survived the admission. Patients were divided into those who reverted to normocapnia (reversible, 40% of surviving patients), and those who remained hypercapnic (chronic, 60% of surviving patients). Reversible patients had higher admission arterial oxygen tension (PaO2) levels than those with chronic hypercapnia (6.4 +/- 1.3 kPa (mean +/- SD), as compared to 5.7 +/- 1.1 kPa) better pulmonary function (forced expiratory volume in one second (FEV1) 35 +/- 16% predicted, as compared to 26 +/- 7.9), and a lower prevalence of cor pulmonale (30% as compared to 63% of patients). No admission variable(s) distinguished individual patients as reversible or chronic hypercapnic, and, in particular, admission arterial carbon dioxide tension (PaCO2) and pH levels were similar in both groups. Furthermore, there were no differences between survivors and those 16 patients who died during the admission, apart from a higher urea level among those who died. These findings suggest that reversible patients have milder underlying disease than those with chronic hypercapnia. Our data establish the high prevalence of reversible hypercapnia among patients hospitalized with exacerbations of COPD, and, furthermore, indicate that patients who are normocapnic in the stable state can develop similar levels of hypercapnia during exacerbations as those with chronic hypercapnia.

The effect of estradiol, trenbolone acetate, or zeranol on growth rate, mammary development, carcass traits, and plasma estradiol concentrations of beef heifers

The effect of a single implantation (on d 1) with one or two long-acting, biodegradable estradiol implants (1E or 2E) on plasma estradiol concentrations in beef heifers was determined. The growth rates of these (2E) heifers, and of heifers repeatedly implanted with trenbolone acetate (TBA) or zeranol (Z) on d 1, 84, 168, and 252 of the trial, were compared to growth rates of controls. Trenbolone acetate alone was compared to TBA + 2E, and 2E was compared to 1E. At a mean age of 84 d (d 1 of experiment), 81 Hereford x Friesian heifers were allocated at random to the following treatments: Control (n = 15); TBA (n = 15); 1E (n = 12); 2E (n = 15); Z (n = 13); or TBA + 2E (n = 11). Mean live weight (kg) prior to slaughter on d 368 and hot carcass weight (kg) for heifers assigned to treatment Groups 1 to 6, respectively, were 366 and 200, 391 and 212, 374 and 201, 386 and 207, 387 and 210, and 391 and 208 (residual SD = 30.3 and 20.2). Heifers assigned to both the 2E and Z treatments were heavier on d 368 (P less than .05) and had longer teats on d 279 (P less than .05), less pelvic fat (P less than .05), and heavier kidneys (P less than .005) than control heifers. Heifers assigned to the TBA treatment had shorter teats on d 279 (P less than .001) but greater final live weight (P less than .05) and carcass weight than control heifers. Heifers given TBA alone had more pelvic fat (P less than .05) and lighter kidneys (P less than .05) than those given TBA + 2E. Mean estradiol concentrations in both the ipsilateral and contralateral jugular veins of heifers assigned to the 2E and TBA + 2E treatments, and in the ipsilateral jugular veins of heifers given 1E, were greater (P less than .05) than those in control heifers; concentrations did not decline during the experiment.

Percussion of the chest re-visited: a comparison of the diagnostic value of ausculatory and conventional chest percussion

Percussion of the chest is thought to be insensitive in detecting small or deeply situated chest lesions. A newer technique, ausculatory percussion, has been reported as having a far higher sensitivity. In a controlled blind study the diagnostic value of conventional chest percussion compared with ausculatory percussion was defined using the chest x-ray as a gold standard. The prevalence of disease in 100 lung fields was 26%. The majority of lesions were not detected by either technique resulting in very low sensitivities of 15.4% for conventional percussion and 19.2% for ausculatory percussion. A positive result with ausculatory percussion was twice as likely to be false as true (positive predictive value 31.2%). The technique did not add to the diagnostic value of conventional percussion. Both techniques have major limitations. Patients with suspected lung disease still require chest x-ray examination if percussion is normal.