A salamander's top down effect on fungal communities in a detritivore ecosystem.

The soil decomposer community is a primary driver of carbon cycling in forest ecosystems. Understanding the processes that structure this community is critical to our understanding of the global carbon cycle. In North American forests, soil fungal communities are regulated by grazing soil invertebrates, which are in turn controlled by the predatory red-backed salamander (Plethodon cinereus). The presence of these soil invertebrate taxa is known to exert direct top-down control via selective grazing on saprotrophic fungi, with direct consequences for biogeochemical cycling in soil. We investigated whether the removal of P. cinereus would relieve top-down control on decomposer fungal communities in a tri-trophic mesocosm study. Fungal communities were characterized using metabarcoding and high-throughput DNA sequencing. The ß-diversity of fungal communities differed between salamander presence and absence treatments with a strong effect on saprotrophic fungal communities. We concluded that P. cinereus, a mesopredator in the detritivore food chain, exerts a prominent control on the composition and functional diversity of fungal communities in soil through a multi-trophic top-down process. Given their capacity to govern the compositions of soil invertebrates, the activity of these amphibians may be important for regulating ecosystem function and nutrient cycling in temperate forest systems.

Interventions to regulate ordering of serum magnesium levels: report of an unintended consequence of decision support.

BACKGROUND: Unintended consequences of computerized patient care system interventions may increase resource use, foster clinical errors, and reduce users' confidence. OBJECTIVE: To evaluate three successive interventions designed to reduce serum magnesium test ordering through a care provider order entry system (CPOE). The second, modeled after a previously successful intervention, caused paradoxical increases in magnesium test ordering rates. DESIGN: A time-series analysis modeled weekly rates of magnesium test ordering, underlying trends, the impact of the three successive interventions, and the impact of potential covariates. The first intervention exhorted users to discontinue unnecessary tests recurring more than 72 hours into the future. The second displayed recent magnesium, calcium, and phosphorus test results, limited testing to one test instance per order, and provided education regarding appropriate indications for testing. The third targeted only magnesium ordering, displayed recent results, limited testing to one instance per order, summarized indications for testing, and required users to select an indication. PARTICIPANTS: Clinicians at Vanderbilt University Hospital, a 609-bed academic inpatient tertiary care facility, from 1998 through 2003. MEASUREMENTS: Weekly rates of new serum magnesium test orders, instances, and results. RESULTS: At baseline, there were 539 magnesium tests ordered per week. This decreased to 380 (p = 0.001) per week after the first intervention, increased to 491 per week (p < 0.001) after the second, and decreased to 276 per week (p < 0.001) after the third. CONCLUSION: A clinical decision support intervention intended to regulate testing increased test order rates as an unintended result of decision support. CPOE implementers must carefully design resource-related interventions and monitor their impact over time.

The impact of peer management on test-ordering behavior.

BACKGROUND: Laboratory testing of hospitalized patients, although essential, can be expensive and sometimes excessive. Attempts to reduce unnecessary testing have often been difficult to implement or sustain. OBJECTIVE: Use of peer management through a resource utilization committee (RUC) to favorably modify test-ordering behavior in a large academic medical center. DESIGN: Interrupted time-series study. SETTING: Medical center with inpatient care provider order entry (CPOE) system and database of ordered tests. PARTICIPANTS: Predominantly housestaff physicians but all clinical staff (attending physicians, housestaff, medical students, nurses, advance practice nurses, and other clinical staff) at Vanderbilt University Hospital who used CPOE systems. INTERVENTION: The RUC analyzed the ordering habits of providers during previous years and made 2 interventions by modifying software for the CPOE system. The committee first initiated a daily prompt in the system that asked providers whether they wanted to discontinue tests scheduled beyond 72 hours. After evaluating this first intervention, the committee further constrained testing options by unbundling serum metabolic panel tests (sodium, potassium, chloride, bicarbonate, glucose, blood urea nitrogen, and creatinine tests) into single components and by reducing the ease of repeating targeted tests (including electrolyte, blood urea nitrogen, creatinine, and glucose tests; electrocardiography; and portable chest radiography). MEASUREMENTS: Pre- and postintervention volumes of tests; proportion of patients with abnormal targeted chemistry levels after 48 hours; rates of repeated admission, transfer to intensive care units, and mortality; adjusted coefficient of variation for test ordering; and length of stay. RESULTS: Voluntary reduction of testing beyond 72 hours (first intervention) decreased orders for metabolic panel component tests by 24% (P = 0.02) and electrocardiograms by 57% (P = 0.006) but not orders for portable chest radiographs. Prospective constraints on recurrent test ordering with panel unbundling (second intervention) produced an additional decrease of 51% for metabolic panel component tests (P < 0.001) and 16% for portable chest radiographs (P = 0.03). Incidence of patients with abnormal targeted blood chemistry levels after 48 hours decreased after the intervention (P = 0.02). Postintervention-adjusted coefficients of variation decreased for metabolic panel component tests (P = 0.03) and electrocardiography (P = 0.04). Rates of (adjusted) monthly readmission, transfers to intensive care units, hospital length of stay, and mortality were unchanged. LIMITATIONS: Other activities occurring during the time period of the interventions might have influenced some test-ordering behaviors, and we assessed effects on only a limited number of commonly ordered tests. CONCLUSIONS: Peer management reduced provider variability by addressing the imperfect ability of clinicians to rescind testing in a timely manner. Hospitals with growing health care costs can improve their resource utilization through peer management of testing behaviors by using CPOE systems.

Clinicians' perceptions of clinical decision support integrated into computerized provider order entry.

Computerized provider order entry systems can improve patient care by integrating clinical decision support. Decision support is most effective when its content and delivery are acceptable. The authors report the results of a multifaceted survey of the attitudes of housestaff and medical student users of a provider order entry system with integrated decision support at an academic medical center. The survey contained 16 items covering four themes: efficiency, quality of care, results reporting and embedded guidelines. Responses were captured using a five point Likert scale, and were compared using ANOVA and Bartlett's testing. Out of 491 housestaff and 128 medical students, response rates were 47 and 29%, respectively. Among respondents, 72% agreed or strongly agreed that the provider order entry system improves the quality of care that they provide, 54% that the decision support usually help them to provide quality patient care, and 62% that it improves the efficiency of order entry. Respondents were least likely to agree that the display of prior laboratory results influenced their decision to order a subsequent test. There were no significant differences between subspecialties and by advancing years of training among housestaff. Respondents agreed that the integrated clinical decision support enhanced their medical training.