Browsing by Author "Pham, An T"

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    Comparative analysis of length of stay, hospitalization costs, opioid use, and discharge status among spine surgery patients with postoperative pain management including intravenous versus oral acetaminophen.
    (Curr Med Res Opin, 2017-03-09) Hansen, Ryan N; Pham, An T; Böing, Elaine A; Lovelace, Belinda; Wan, George J; Miller, Timothy E
    BACKGROUND: Recovery from spine surgery is oriented toward restoring functional health outcomes while reducing resource use. Optimal pain management is a key to reaching these objectives. We compared outcomes of spine surgery patients who received standard pain management including intravenous (IV) acetaminophen (APAP) vs. oral APAP. METHODS: We performed a retrospective analysis of the Premier database (January 2012 to September 2015) comparing spine surgery patients who received pain management with IV APAP to those who received oral APAP, with no exclusions based on additional pain management. We performed multivariable logistic regression for the discharge and all cause 30-day readmission to the same hospital outcomes and instrumental variable regressions using the quarterly rate of IV APAP use for all hospitalizations by hospital as the instrument in two-stage least squares regressions for length of stay (LOS), hospitalization costs, and average daily morphine equivalent dose (MED) outcomes. Models adjusted for age, gender, race, admission type, 3M All Patient Refined Diagnosis Related Group severity of illness and risk of mortality, hospital size, and indicators for whether the hospital was an academic center and whether it was urban or rural. RESULTS: We identified 112,586 spine surgery patients with 51,835 (46%) having received IV APAP. Subjects averaged 57 and 59 years of age respectively in the IV APAP and oral APAP cohorts and were predominantly non-Hispanic Caucasians and female. In our adjusted models, IV APAP was associated with 0.68 days shorter LOS (95% CI: -0.76 to -0.59, p < .0001), $1175 lower hospitalization costs (95% CI: -$1611 to -$739, p < .0001), 13 mg lower average daily MED (95% CI: -14 mg to -12 mg, p < .0001), 34% lower risk of discharge to a skilled nursing facility (95% CI: 0.63 to 0.69, p < .0001), and 13% less risk of 30-day readmission (95% CI: 0.73 to 1.03). CONCLUSIONS: Compared to oral APAP, managing post-spine-surgery pain with IV APAP is associated with less resource use, lower costs, lower doses of opioids, and improved discharge status.
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    Phase diagram and aggregation dynamics of a monolayer of paramagnetic colloids
    (2017-06-01) Pham, An T; Zhuang, Yuan; Detwiler, Paige; Socolar, Joshua ES; Charbonneau, Patrick; Yellen, Benjamin B
    We have developed a tunable colloidal system and a corresponding simulation model for studying the phase behavior of particles assembling under the influence of long-range magnetic interactions. A monolayer of paramagnetic particles is subjected to a spatially uniform magnetic field with a static perpendicular component and rapidly rotating in-plane component. The sign and strength of the interactions vary with the tilt angle $\theta$ of the rotating magnetic field. For a purely in-plane field, $\theta=90^{\circ}$, interactions are attractive and the experimental results agree well with both equilibrium and out-of-equilibrium predictions based on a two-body interaction model. For tilt angles $50^{\circ}\lesssim \theta\lesssim 55^{\circ}$, the two-body interaction gives a short-range attractive and long-range repulsive (SALR) interaction, which predicts the formation of equilibrium microphases. In experiments, however, a different type of assembly is observed. Inclusion of three-body (and higher-order) terms in the model does not resolve the discrepancy. We thus further characterize the anomalous behavior by measuring the time-dependent cluster size distribution.