Student nurses' ethical views on responses to the severe acute respiratory syndrome outbreak.

BACKGROUND: Fifteen years have passed since the outbreak of severe acute respiratory syndrome in Hong Kong. At that time, there were reports of heroic acts among professionals who cared for these patients, whose bravery and professionalism were highly praised. However, there are concerns about changes in new generation of nursing professionals. OBJECTIVE: We aimed to examine the attitude of nursing students, should they be faced with severe acute respiratory syndrome patients during their future work. RESEARCH DESIGN: A questionnaire survey was carried out to examine the attitude among final-year nursing students to three ethical areas, namely, duty of care, resource allocation, and collateral damage. ETHICAL CONSIDERATIONS: This study was carried out in accordance with the requirements and recommendations of the Central Research and Ethics Committee, School of Health Sciences at Caritas Institute of Higher Education. FINDINGS: Complete responses from 102 subjects were analyzed. The overwhelming majority (96.1%) did not agree to participate in the intubation of severe acute respiratory syndrome patients if protective measures, that is, N95 mask and gown, were not available. If there were insufficient N95 masks for all the medical, nursing, and allied health workers in the hospital (resource allocation), 37.3% felt that the distribution of N95 masks should be by casting lot, while the rest disagreed. When asked about collateral damage, more than three-quarters (77.5%) said that severe acute respiratory syndrome patients should be admitted to intensive care unit. There was sex difference in nursing students' attitude toward severe acute respiratory syndrome care during pregnancy and influence of age in understanding intensive care unit care for these patients. Interestingly, 94.1% felt that there should be a separate intensive care unit for severe acute respiratory syndrome patients. CONCLUSION: As infection control practice and isolation facilities improved over the years, relevant knowledge and nursing ethical issues related to infectious diseases should become part of nursing education and training programs, especially in preparation for outbreaks of infectious diseases or distress.

Indexing glomerular filtration rate to suit children.

UNLABELLED: In order to be able to compare individuals of differing size, glomerular filtration rate (GFR) is conventionally indexed to body surface area (BSA). This does not, however, suit children because they naturally have a relatively high BSA simply because of their small size. The aim of the study was to identify an appropriate simple whole-body variable based on height and weight suitable for indexing GFR that would be simultaneously appropriate for both children and adults. METHODS: A database of 532 routine clinical GFR measurements, each based on 3 venous blood samples obtained between 2 and 4 h after injection of (51)Cr-ethylenediaminetetraacetic acid, was analyzed to give GFR and, using only the half-time of the slope of the clearance curve, the quotient GFR to extracellular fluid volume (ECV). BSA was obtained from the Haycock formula, which is based on height and weight raised to indices to give units of area. Both GFR and GFR/ECV were corrected for the 1-compartment assumption using previously published empiric correction formulas. ECV was obtained by dividing GFR by GFR/ECV. An equation analogous to Haycock's was derived in which the indices of height and weight were varied to give an iterative best fit to ECV instead of BSA. RESULTS: GFR, ECV, and BSA increase as functions of age until about age 13 y, corresponding to a BSA of about 1.35 m(2), which was taken as the cutoff point between children and adults. As humans grow, their ratio of height to effective radius changes as a nonlinear function of surface area. Humans must therefore change shape as they grow. Moreover, the ECV-to-weight ratio decreases as a function of body size, suggesting that humans also change body composition as they grow. The new equation, giving an iterative best fit to ECV, was ECV = weight(0.6469) x height(0.7236) x 0.02154. ECV, either measured or estimated from the new equation, corresponding to a BSA of 1.73 m(2), was 12.9 L. Expressed as values normalized to the corresponding average adult values, the new equation and the second-order polynomial fit to ECV were superimposed as they increased as functions of BSA or weight. In contrast, normalized BSA and normalized weight were respectively larger and smaller than normalized ECV in children. GFR indexed to the new equation correlated more closely with GFR indexed to ECV than did GFR indexed to BSA and, along with GFR/ECV, showed a greater fall as a function of age than did GFR/BSA. CONCLUSION: When required in absolute units rather than as a rate of turnover of ECV, GFR is appropriately indexed to indices of height and weight as defined by this new equation, which avoids disadvantages to children from indexing to BSA. This unmasks higher values of filtration function in children than have hitherto been recognized.

Time to complete mixing for the measurement of glomerular filtration rate from single bolus plasma 51Cr-EDTA clearance.

BACKGROUND AND METHOD: In the measurement of glomerular filtration rate from the plasma clearance of 51Cr ethylenediamine tetraacetic acid by using the slope-intercept method, the first sample is conventionally taken at 2 h, the time by which it is generally assumed that the clearance curve has reached a single exponential. We examined this assumption by comparing the slopes, alpha 12 and alpha 23, based, respectively, on samples at 2 and 3 h, and at 3 and 4 h. RESULTS: In 421 patient studies in whom the first sample was taken between 110 and 130 min after injection, the mean ratio, alpha 12/alpha 23, was 1.101 (SEM 0.011) which is significantly higher than unity (P<<0.001). The relationship between alpha 12/alpha 23 and the slope, alpha 13 (which is a measure of filtration function already indexed for body size) based on all three samples was negative. By modelling the relationship between mixing time and alpha 13 it was shown that this relationship suggests delayed mixing of the indicator throughout its distribution volume and is inconsistent with irreversible binding of indicator to plasma protein. A significant positive association was observed between alpha 12/alpha 23 and age, but this is largely explained by a generally poorer filtration function in the older age group since low levels of alpha 13 theoretically predict a longer mixing time. In 188 patient studies in whom the first sample was taken more than 130 min after injection, the mean ratio, alpha 12/alpha 23, was 1.055 (SEM 0.017) which is still significantly higher than unity (P<<0.005) but significantly less than the ratio based on studies in which the first sample was taken at 110-130 min (P<0.02). The ratio alpha 12/alpha 23 still showed a significant relation (positive) with age but not with filtration function. CONCLUSION: This error in the estimation of glomerular filtration rate to which delayed mixing leads will make its greatest impact when using the simplified slope-only technique, but can be minimized by delaying the first blood sample.

Measuring SSRI occupancy of SERT using the novel tracer [123I]ADAM: a SPECT validation study.

PURPOSE: Serotonergic brain regions play a crucial role in the modulation of emotion, and serotonergic dysfunction may contribute to several neurological disorders. [123I]ADAM is a novel SPECT tracer which binds with high affinity to serotonin transporters (SERT). The objective of this study was to compare different methods for the quantification of tracer binding and to develop a simplified single-scan protocol for this tracer, as well as to investigate its potential for characterisation of the transporter occupancy versus plasma concentration curve of a selective serotonin re-uptake inhibitor (SSRI). METHODS: Dynamic SPECT scans were performed on 16 healthy volunteers after administration of approximately 150 MBq [123I]ADAM. Data were acquired from the time of injection until approximately 5.5 h after injection in 30- or 45-min sessions. Each subject was scanned twice: with and without pre-treatment with the SSRI citalopram in various dosage regimens. The plasma concentration of citalopram (C(p)) was determined from venous samples. Images were reconstructed by filtered back-projection with scatter and attenuation correction. Tracer binding was quantified for midbrain, striatum and thalamus using cerebellum as a reference region. Quantification was done by kinetic modelling, graphical analysis and multi-linear regression, as well as by the ratio method, with binding potential (BP2) as the outcome measure. The SERT occupancy by citalopram was determined relative to the baseline scan for each subject, and the occupancy versus C(p) curve was fitted with the E(max) model. RESULTS: The highest binding of [123I]ADAM was in midbrain (mean baseline BP2+/-SD=1.31+/-0.29), with lower binding in thalamus (0.79+/-0.16) and striatum (0.66+/-0.13). There was good agreement between BP2 values obtained by different quantification methods. Using the ratio method, the best agreement with kinetic modelling was obtained with data from the time interval [200,260] min after injection. The fitting of the midbrain occupancy curve yielded a maximum occupancy of 84% and a plasma concentration required to reach 50% of the maximum of 2.5 ng/ml, with a goodness-of-fit variability of 13% (SD). CONCLUSION: Binding of [123I]ADAM to SERT in midbrain can be quantified with a single scan starting 200 min after injection. However, the variability of estimated occupancy values may be too high for critical assessment of occupancy of SERT by SSRI.