Understanding the role of peace of mind in childhood vaccination: A qualitative study with members of the general public.

BACKGROUND: Recent debates on the introduction of new childhood vaccines in the UK have suggested that 'peace of mind' (PoM) might influence decision making. The aim of this study is to ascertain the importance of 'PoM' in individuals' decision making. METHODS: Four focus groups were conducted in the UK. Participants were 22 females and 2 males, aged 18-74 years, with a selection of non-parents, parents, guardians and foster carers. Data were analysed using an inductive thematic framework approach and conceptualised using the Health Belief Model, which provided an overview of participants' perceptions and behaviours about childhood vaccinations. RESULTS: Vaccine associated PoM was associated with individuals' perceptions of disease severity, with individuals feeling more reassurance after obtaining vaccinations against diseases that they considered to be severe compared to relatively mild diseases. Conversely, concerns about vaccination side-effects reduced participants PoM, but the duration of this effect varied between individuals. Other factors, such as social pressure and the emotional anxiety related to children's feelings, or physical reactions, to vaccinations also negatively impacted on participants' vaccine associated PoM. CONCLUSION: Vaccine associated PoM was a consideration for some participants seeking vaccinations but was only a minor motivating factor for these individuals. These differences stemmed from whether participants received PoM from the uptake of a vaccination because they perceived some intrinsic benefit from it or, conversely, they considered vaccinations as a routine health intervention. Overall, vaccine related PoM varied between participants in magnitude and fluctuated over time, even in the same individuals.

A step-wise approach to developing indicators to compare the performance of maternity units using hospital administrative data.

Hospital administrative data are attractive for comparing performance of maternity units because of their often large sample sizes, lack of selection bias and the relatively low costs of accessing these data compared with conducting primary data collection. However, using administrative data to develop indicators can also present challenges including varying data quality, the limited detail on clinical risk factors and a lack of structural and user experience measures. This review illustrates how to develop performance indicators for maternity units using hospital administrative data, including methods to address the challenges that administrative data pose. TWEETABLE ABSTRACT: How to develop maternity indicators from administrative data.

Effect of pulmonary edema on tracheal diameter.

BACKGROUND: Though it is well known that cardiogenic and noncardiogenic pulmonary edema can cause changes in lung mechanics, actual alterations in tracheal diameter have not been described. OBJECTIVE: To evaluate the effects of pulmonary edema induced by increased left atrial pressure (cardiogenic) and Perilla ketone (PK; noncardiogenic) on tracheal diameter in chronically instrumented awake sheep. METHODS: We investigated the effects of two mechanistically distinct types of pulmonary edema on tracheal diameter in chronically instrumented awake sheep. Cardiogenic pulmonary edema (analogous to congestive heart failure in humans) was induced by increasing left atrial pressure ( upward arrowP(LA)) by inflating the balloon on a Foley catheter positioned in the mitral valve annulus to cause partial obstruction to flow across the valve (n = 18). Noncardiogenic pulmonary edema (increased pulmonary microvascular permeability pulmonary edema analogous to the acute respiratory distress syndrome in humans) was produced by the intravenous administration of PK (n = 11). Lateral chest radiographs (CXRs) were scored by a standardized 5-point scoring system for the severity of pulmonary edema, and tracheal diameter was measured at a fixed location in the carina. Three radiologists, blinded to sheep identification number and experimental protocol, evaluated the radiographs independently at different points in time for edema severity and tracheal diameter. The sheep were sacrificed immediately after the final CXR, and wet/dry lung weight ratio (W/D ratio) was determined. RESULTS: Both upward arrowP(LA) and PK were associated with statistically significant tracheal narrowing ( upward arrowP(LA): 20.3 +/- 0.6 to 15.1 +/- 0.9 mm; PK: 20.2 +/- 0.6 to 14.1 +/- 1.4 mm). Tracheal narrowing correlated with the severity of the pulmonary edema determined radiographically ( upward arrowP(LA): r = -0.69, p < 0.01; PK: r = -0.62, p < 0.01) and by W/D ratio ( upward arrowP(LA): r = -0.64, p < 0.05; PK: r = -0.54, p < 0. 05). CONCLUSIONS: We conclude that tracheal narrowing occurs in sheep models of both cardiogenic and noncardiogenic pulmonary edema and that the degree of narrowing correlates with the severity of the edema.

The Hermansky-Pudlak syndrome.

Hermansky-Pudlak Syndrome (HPS) is a rare, inheritable disorder characterized by the classic triad of oculo-cutaneous albinism, platelet dysfunction, and ceroid deposition. An associated complication is pulmonary fibrosis with progressive restrictive lung disease. This report discusses the lung involvement often seen in this condition correlated with radiography, computed tomography, high-resolution computed tomography, and the underlying pathology, by means of two such afflicted siblings. The elder died of respiratory failure while awaiting lung transplantation. The younger sibling is currently undergoing evaluation for transplantation.

The plain chest radiograph and clinical management of pulmonary edema in pregnancy.

OBJECTIVE: To evaluate the reproducibility of radiographic quantification of pulmonary edema on the supine plain chest radiograph and to correlate the radiographic appearance of edema with the clinical assessment and treatment of pulmonary edema. STUDY DESIGN: Retrospective, blind, descriptive study of 24 women with singleton pregnancies in the last trimester selected because of a clinical question of pulmonary edema. RESULTS: Interobserver variability between radiologists resulted in an average weighted kappa of .71 in grading edema on a 0-3 scale where 0 = no edema and 3 = alveolar flooding. The vascular pedicle (a measure of central circulating volume) was larger among patients who received furosemide (63.4 mm) than those who did not (57.0 mm) (P = .01). The vascular pedicle was also larger among patients receiving tocolytics or steroids (62.8 mm) than those who did not (56.0 mm) (P = .01). The radiographic edema score tended to be lower in patients who received tocolytics and steroids (P = .05). The other correlations were not significant. CONCLUSION: Radiographic assessment of pulmonary edema shows fair to good reproducibility, but the clinical correlations are modest. A wider understanding of the wealth of physiologic information available on the plain chest radiograph may prove invaluable in understanding the clinical course and treatment of these patients.

Comparison of the pulmonary dysfunction caused by cardiogenic and noncardiogenic pulmonary edema.

We designed a series of experiments to compare the pulmonary dysfunction observed in models of cardiogenic and noncardiogenic pulmonary edema in chronically instrumented awake sheep. Cardiogenic pulmonary edema was induced by inflating the balloon of a Foley catheter surgically positioned in the mitral valve orifice causing increased left atrial pressure (increases PLA). Noncardiogenic pulmonary edema was induced by intravenous infusion of Perilla ketone (PK). Calculated microvascular pressure remained constant during PK infusion but increased from 9.4 +/- 0.7 to 42.8 +/- 2.4 cm H2O during increases PLA. Comparable increases in lung lymph flow (QL) were observed in the two protocols (five to seven times baseline). Pulmonary edema as quantified by chest radiograph scores increased from 0 (normal) to 2.9 +/- 0.5 and 3.4 +/- 0.1 in the PK and increases PLA groups, respectively. Room air alveolar to arterial oxygen pressure difference (P[A-a]O2) increased from 24 +/- 3 to 46 +/- 7 mm Hg in the PK group and from 23 +/- 4 to 56 +/- 6 mm Hg in the increases PLA group. Dynamic compliance of the lungs (Cdyn) expressed as the percentage of the baseline value decreased to 53 +/- 7 and 50 +/- 7% in the PK and increases PLA groups, respectively. Resistance to airflow across the lungs (RL) increased from 2.5 +/- 0.6 to 3.3 +/- 0.8 cm H2O.L-1.sec-1 in the PK group and from 1.4 +/- 0.3 to 4.2 +/- 1.1 in the increases PLA group. Significant correlations were observed between changes in the severity of pulmonary edema observed on chest radiographs, Cdyn, delta P(A-a)O2, and QL in both the increases PLA groups. We conclude that similar degrees of pulmonary edema, regardless of the mechanism, are associated with similar changes in QL, Cdyn, and delta P(A-a)O2. Hydrostatic pulmonary edema appeared to cause greater changes in RL than that resulting from increased microvascular permeability.

Use of capillary optics as a beam intensifier for a Compton x-ray source.

The use of Kumakhov capillary optics will significantly enhance the performance of near-monochromatic, Compton backscattered x-ray programs. The Vanderbilt University Medical Free-Electron Laser Center is developing the capability to create these tunable x rays for medical imaging. The present transport has only reflection optics, and the beam is quite large in diameter at the laboratory. Low loss collimation of this beam would allow higher x-ray intensities after transport. This article describes experimental and computer simulation results which predict the expected performance for a multifiber Kumakhov collimator for use in the x-ray beam transport. Estimates from our research are that a multifiber optic formed of individual polycapillary fibers could be used to capture the full 7 mrad of the Vanderbilt x-ray beam and collimate it to a 1-2 mrad divergence with approximately 40%-50% transmission efficiency. This optic should increase the x-ray intensity at the laboratory level by a factor of > or = 5 by decreasing the beam divergence and subsequent spot size. Additionally, analysis of monolithic optics of fused multicapillary fibers predicts an increase in the intensity of the x rays at the laboratory by a factor of 55. These optics can have tapered channels that greatly decrease their exit divergence. This will greatly enhance the capabilities of this unique x-ray source. This article reports the initial results from a collaboration between Vanderbilt, The Center for X-Ray Optics at University at Albany, SUNY, and X-Ray Optical Systems in Albany, NY.

Attenuation of monochromatic X-rays by normal and abnormal breast tissues.

RATIONALE AND OBJECTIVES: A prior study indicated that differences in the x-ray linear attenuation coefficients of cancerous and normal breast tissues tend to increase as the energy of the incident beam decreases. The authors investigated x-ray energies down to 20 keV. In the current study, the linear attenuation coefficients for normal and selected cancerous breast tissues within the energy range of 14 to 18 keV were determined. METHODS: Fifty breast biopsy specimens consisting of a mixture of breast malignancies, normal tissues, fat specimens, and tumors grown in rats were used. X-ray linear attenuation coefficients were measured for each sample within the energy range of 14.15 to 18 keV, using monoenergetic x-rays from beamline X-19A at the National Synchrotron Light Source at Brookhaven National Laboratory. Each sample was measured at 130 different energies starting at 14.15 keV with step sizes of 0.030 keV. Correlation of the measured attenuation coefficients for cellular makeup was performed. RESULTS: The mean of linear attenuation coefficients for samples classified as "cancers" was 10.9% higher than the mean of samples classified as "normal" breast tissues and was 66.5% higher than the mean of samples classified as normal breast fat. CONCLUSIONS: Differences in the linear attenuation coefficients of monochromatic x-rays between 14.15 and 18 keV do exist between normal and cancerous tissues, but there is some degree of overlap.

Radiographic issues in adult respiratory distress syndrome.

Despite significant technical limitations, the portable chest radiograph remains the primary tool for radiographic evaluation of patients with the acute respiratory distress syndrome (ARDS). Using good-quality films, experienced observers usually can distinguish permeability-induced from nonpermeability-induced pulmonary edema. In patients with ARDS, the chest radiograph typically shows rapid dramatic deterioration within 24 hrs, as indicated by the development of patchy peripheral infiltrates. Radiographic density may increase in severity for 5 to 7 days, after which time, further deterioration usually signals the occurrence of another process (e.g., infection, fluid overload). In the period beyond 1 wk, where the radiograph usually remains relatively stable, the chest radiograph is most useful in detecting complications of therapy, predominantly barotrauma. The vast majority of survivors of ARDS show improvement in their radiographs within the first 10 to 14 days after the onset of illness. Failure to show improvement during this time is a poor prognostic factor. Computed tomography is a useful modality in patients with questionable chest radiograph findings, provided that the patients are stable enough to leave the ICU for evaluation.

Hydrostatic pulmonary edema in sheep. Effects of bronchial artery embolization on the plain chest radiograph.

RATIONALE AND OBJECTIVES: The bronchial circulation may influence pulmonary edema. This study evaluates possible effects of bronchoesophageal artery embolization on the plain film manifestations of hydrostatic pulmonary edema in sheep. METHODS: Anteroposterior and lateral chest radiographs were obtained during the induction of pulmonary edema both before and after embolization of the bronchoesophageal artery in six adult sheep. Interstitial lines and perivascular, segmental bronchial, proximal bronchial, carinal, tracheal, and parenchymal edema were evaluated. RESULTS: Only parenchymal edema was graded consistently. Though edema increased with left atrial pressure before embolization (P < .001), there was no similar change afterward. The embolized animals tended to be more edematous by the first film. CONCLUSION: Rather than any protective effect, bronchoesophageal artery embolization may increase edema. This model may be inappropriate for further investigation of the bronchial circulation in the development of human pulmonary edema.

Comparison of nonionic and ionic contrast agents in the rabbit lung.

The objective of this study was to determine the short- and long-term radiographic, physiologic and histologic changes elicited in the lung of rabbits following the aspiration of commonly used radiographic contrast agents. All agents used, including nonionic agents, caused radiographically evident pulmonary edema which cleared by 24 hours. The contrast materials with higher osmolality, viscosity, and iodine content elicited the greatest physiologic and pathologic changes. No differences were found between an ionic and a nonionic agent with similar viscosities and iodine content, despite a lower osmolality in the nonionic agent. No contrast agent is innocuous when introduced into the lung.

Generation of "soft x-rays" by using the free electron laser as a proposed means of diagnosing and treating breast cancer.

The diagnosis and treatment of breast lesions may be markedly enhanced by the use of a unique new source of near-monochromatic x-rays. Concentric beams of near-monochromatic x-ray photons may be generated by collision of the free electron laser (FEL) electron beam with the optical beam in an interaction zone that delivers the x-rays to a shirtsleeve environment. The absence of Compton scatter and the photoelectric interaction within tissues improves conspicuity of lesions by two to six times. Increased attenuation of x-rays in malignant vs. normal tissues makes tumors more obvious. K-edge subtraction allows chemical analysis of tumors in vivo--all at radiation doses that are one-tenth to one-fiftieth that delivered by the lowest-dose mammographic x-ray technique available. This allows for an increased sensitivity and specificity and permits prediction of histology, negating necessity for biopsies. Selective bond-breaking at depth in tissues as well as x-ray-activated photodynamic therapy are also being explored.

Near-monochromatic X-ray beams produced by the free electron laser and Compton backscatter.

The intense photon output of a free electron laser may be made to collide with its own high energy electron beam to create nearly monochromatic x-rays using Compton backscatter techniques. These x-rays can be used for imaging and non-imaging diagnostic and therapeutic experiments. The initial configuration of the Vanderbilt Medical Free Electron Laser (Sierra Laser Systems, Sunnyvale, CA) produces intense x-rays up to 17.9 keV, although higher energies are easily attainable through the use of frequency doubling methods, alteration of the energy of the electron beam and coupling to conventional laser inputs.

Inexpensive, air-driven ventricular assist or replacement device for use in MR research.

A simple, inexpensive, non-magnetizable, pulsatile air-driven pump has been devised for use in magnetic resonance environments. The pump has a variable stroke volume and stroke rate, is easily cleaned and sterilized, requires relatively small priming volumes and causes no observable hemolysis when blood is used as the perfusate. This device is usable for phantoms, isolated organs or in situ preparations.