What do Attending Physicians Contribute in a House Officer-Based Ambulatory Continuity Clinic?

OBJECTIVE: To study the educational contributions of attending physicians in an internal medicine house staff ambulatory clinic. DESIGN: Cross-sectional, self-administered survey. SETTING: University-affiliated general internal medicine practice. PATIENTS/PARTICIPANTS: Internal medicine residents and attendings. MEASUREMENTS AND MAIN RESULTS: Attending and resident perceptions of whether attendings made contributions to teaching points, diagnosis (DX), therapy (RX), and health care maintenance (HCM) were assessed in 428 patient encounters. Resident assessments significantly exceeded attending self-assessments of contributions to teaching points (82% vs 74%, P = .001), DX (44% vs 34%, P = .001), RX (61% vs 55%, P = .02), and HCM (19% vs 15%, P = .04). Both residents and attendings perceived that contributions declined progressively with increasing resident year (P<.05). Primary care and categorical residents assessed attending contributions comparably. However, attendings perceived contributing more to RX and HCM for categorical residents than primary care (P<.05). Male and female residents assessed attending contributions comparably. However, attendings perceived contributing generally more to DX in male residents than female (P = .003). In 8% of encounters, either residents or attendings felt that patient evaluation by the attending was needed. In these encounters with personal patient evaluation by attendings, both residents and attendings felt that attendings made more contributions to DX (P = .001) and teaching points than in other encounters. CONCLUSIONS: Attending physicians consistently underestimate their perceived contributions to house officer ambulatory teaching. Their personal patient evaluation increases assistance with DX and teaching points. Given perceived declining contributions by training year, attendings may need to identify other teaching strategies for interactions with senior residents

Primary Care Physicians' Use of Lumbar Spine Imaging Tests: Effects of Guidelines and Practice Pattern Feedback

OBJECTIVE: To reduce variability in primary care physicians' use of procedures for imaging the lumbar spine. DESIGN: Controlled intervention using clinical practice guideline and practice pattern feedback. STUDY SAMPLE: Sixty-seven internists and 28 family practitioners in a large, group-model HMO. MEASUREMENTS AND MAIN RESULTS: Intervention group physicians received the clinical practice guideline for low back pain, followed after 4 months by three bimonthly feedback reports on their current use rates for lumber spine x-rays and computed tomography and magnetic resonance imaging scans of the lumbar spine. Control group physicians received neither the guideline nor the feedback reports. Automated radiology utilization data were used to compare intervention and control group physicians' changes in use rates and variability in use rates over the course of the study period. Neither the guideline alone nor the guideline plus feedback was associated with a significant decrease in use rates or in the variability in use rates for the lumbar spine imaging procedures under study. CONCLUSIONS: Clinical practice guidelines and practice pattern feedback fail to achieve their goals when features of the practice setting and patient expectations and behavior are not identified and addressed

Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry

Perthitic alkali feldspar primocrysts in layered syenites in the Klokken intrusion in South Greenland, underwent dissolution–reprecipitation reactions in a circulating post-magmatic aqueous fluid at &#8764;450°C, and are to a large degree pseudomorphs. These 'mutual replacement' reactions provide a perfect natural experiment with which to study trace element partitioning between sodium and potassium feldspars growing simultaneously. The reactant 'phase' was a cryptoperthitic feldspar consisting of low albite and low microcline in a coherent sub-&#956;m 'braid' intergrowth and the product phases were 'strain-free' incoherent subgrains of low albite and low microcline forming microporous patch perthites on scales up to 200 μm. The driving force for the reaction was reduction of coherency strain energy. The mechanisms of this process are described in Part I. Five mixed braid perthite–patch perthite crystals were analysed for major and trace elements using laser ablation-inductively coupled plasma mass spectrometry with a 19 μm beam diameter. This gave bulk analyses of the braid texture, which were in the range Ab73–54Or45–27An4.3–0.8, but could resolve Ab- and Or-rich patches in patch perthite. The major element bulk compositions of the crystals were retained during the replacement reactions. Major components in patches plot on tielines in the Ab–Or–An ternary system that pass through or very close to the parent braid perthite composition and indicate local equilibrium on the scale of a few tens of mm. Many trace elements, including REE, were lost to the fluid during the deuteric reactions, but the effect is large only for Fe and Ti. Cs, Pb and Sr were added to some crystals. Plots of log distribution coefficient D for Rb, Ba, Pb, Eu2+, La and Ce between Or- and Ab-rich patches against ionic radius are straight lines, assuming eightfold coordination, and to a first approximation are independent of ionic charge. K also lies on these lines, and the smaller ions Na and Ca lie close to them. The best linear fits were obtained using ionic radii for [8]K and [8]Ca, but there is ambiguity as to whether [7]Na or [5]Na is most appropriate. The linear relationship shows that the listed trace elements are in the feldspar M-site rather than in inclusions. Tl is in M although an exact D could not be obtained. The very large Cs ion partitions strongly into the Or-rich phase but its D value appears to be less than predicted by extrapolation. The near-linearity arises because partitioning is occurring between two solids into sites which have similar Young's moduli, so that the parabolas that normally represent trace element partitioning between crystals and liquids (which have negligible shear strength) approximately cancel out. Ga and Be are in T-sites, as well as some of the Fe and Ti present, although part is in oxide inclusions. The site of Sc is unclear, but if structural it is likely to be T. Partitioning on M-sites is a potential geothermometer but because the effective size of the irregular M-site is defined by its K and (Na + Ca) contents, which are controlled by ternary solvus relationships, its calibration is not independent of conventional two-feldspar geothermometers. Trace elements may however provide a useful means of confirming that feldspar pairs are in equilibrium, and of recognising feldspar intergrowths produced by non-isochemical replacement rather than exsolution. Two-feldspar geothermometry for the ternary phases in the low-albite microcline patch perthites gives temperatures above the stability range of microcline, markedly so if a correction is made for Si–Al ordering. This is probably because current geothermometers are too sensitive to low concentrations of An in ordered Or-rich feldspars. This interpretation is supported by two-feldspar assemblages growing at known temperatures in geothermal systems and sedimentary basins