Cost Modifications during the Early Years of the Use of the National Cardiovascular Data Registry for Quality Improvement.

OBJECTIVES: Quality improvement (QI) initiatives based on data from international registries have been reported previously; however, there is a lack of information on the impact on the costs of medical care associated with the use of these tools. METHODS: Patients admitted due to myocardial infarction (MI), included in the ACTION Registry® and CathPCI Registry®, in a private Brazilian hospital (i.e., the reference hospital) were analyzed. The costs of care of these patients were compared to the costs of MI admissions in nine similar hospitals not included in the same QI program. Regression models were used to analyze the cost change over time between the two groups of hospitals. Readmission rates were compared using logistic regression, adjusting for the same variables as in the cost model. RESULTS: Overall, the annual medical cost inflation in Brazil was higher than the annual cost trend in the reference hospital during the period of analysis. Moreover, the annual in-hospital costs indicate that the reference hospital has a statistically significant 6% lower cost trend for patients with acute MI, compared to patients with the same diagnostic code in the comparison hospitals group, in an adjusted analysis (p-value=0.041). Using multivariable analysis, the readmission rates were also found to be significantly lower in the reference hospital than in the comparison hospitals, with an odds ratio of 0.68 (p-value=0.042). CONCLUSION: The use of the NCDR® as a benchmark to guide QI programs outside the United States was associated with the positive impact of bending the cost curve to below that of national medical inflation and the comparison hospitals' costs, with a lower incidence of hospital readmission.

Cost modifications during the early years of the use of the national cardiovascular data registry for quality improvement

OBJECTIVES: Quality improvement (QI) initiatives based on data from international registries have been reported previously; however, there is a lack of information on the impact on the costs of medical care associated with the use of these tools. METHODS: Patients admitted due to myocardial infarction (MI), included in the ACTION Registry® and CathPCI Registry®, in a private Brazilian hospital (i.e., the reference hospital) were analyzed. The costs of care of these patients were compared to the costs of MI admissions in nine similar hospitals not included in the same QI program. Regression models were used to analyze the cost change over time between the two groups of hospitals. Readmission rates were compared using logistic regression, adjusting for the same variables as in the cost model. RESULTS: Overall, the annual medical cost inflation in Brazil was higher than the annual cost trend in the reference hospital during the period of analysis. Moreover, the annual in-hospital costs indicate that the reference hospital has a statistically significant 6% lower cost trend for patients with acute MI, compared to patients with the same diagnostic code in the comparison hospitals group, in an adjusted analysis (p-value=0.041). Using multivariable analysis, the readmission rates were also found to be significantly lower in the reference hospital than in the comparison hospitals, with an odds ratio of 0.68 (p-value=0.042). CONCLUSION: The use of the NCDR® as a benchmark to guide QI programs outside the United States was associated with the positive impact of bending the cost curve to below that of national medical inflation and the comparison hospitals' costs, with a lower incidence of hospital readmission.

The Brillouin gain of vector modes in a few-mode fiber.

In this work, we demonstrate the measurement of the Brillouin gain spectra of vector modes in a few-mode fiber for the first time using a simple heterodyne detection technique. A tunable long period fiber grating is used to selectively excite the vector modes supported by the few-mode fiber. Further, we demonstrate the non-destructive measurement of the absolute effective refractive indices (n eff ) of vector modes with ~10-4 accuracy based on the acquired Brillouin frequency shifts of the modes. The proposed technique represents a new tool for probing and controlling vector modes as well as modes carrying orbital angular momentum in optical fibers with potential applications in advanced optical communications and multi-parameter fiber-optic sensing.

High-extinction-ratio silicon polarization beam splitter with tolerance to waveguide width and coupling length variations.

We demonstrate a compact silicon polarization beam splitter (PBS) based on grating-assisted contradirectional couplers (GACCs). Over 30-dB extinction ratios and less than 1-dB insertion losses are achieved for both polarizations. The proposed PBS exhibits tolerance in width variation, and the polarization extinction ratios remain higher than 20 dB for both polarizations when the width variation is adjusted from + 10 to -10 nm. Benefiting from the enhanced coupling by the GACCs, the polarization extinction ratio can be kept higher than 15 dB and the insertion loss is lower than 2 dB for both polarizations when the coupling length varies from 30.96 to 13.76 µm.

Wavelength and bandwidth-tunable silicon comb filter based on Sagnac loop mirrors with Mach-Zehnder interferometer couplers.

We propose and experimentally demonstrate a wavelength and bandwidth-tunable comb filter based on silicon Sagnac loop mirrors (SLMs) with Mach-Zehnder interferometer (MZI) couplers. By thermally tuning the MZI couplers in common and differential modes, the phase shift and reflectivity of the SLMs can be changed, respectively, leading to tunable wavelength and bandwidth of the comb filter. The fabricated comb filter has 93 comb lines in the wavelength range from 1535 nm to 1565 nm spaced by ~0.322 nm. The central wavelength can be red-shifted by ~0.462 nm with a tuning efficiency of ~0.019 nm/mW. A continuously tunable bandwidth from 5.88 GHz to 24.89 GHz is also achieved with a differential heating power ranging from 0.00 mW to 0.53 mW.

High-capacity and low-cost long-reach OFDMA PON based on distance-adaptive bandwidth allocation.

We propose and experimentally demonstrate a distance-adaptive bandwidth allocation scheme to realize high-capacity long-reach orthogonal frequency division multiple access passive optical network (OFDMA PON) with cost-effective electro-absorption modulator (EAM). In our scheme, the subcarriers in downstream OFDM signal are properly allocated to the optical network units (ONUs) with different fiber transmission lengths. By this means, the detrimental influence of power fading induced by dispersion and chirp can be avoided, thus all OFDM subcarriers can be modulated with high-order quadrature amplitude modulation (QAM) format, leading to a high transmission capacity. A proof-of-concept experiment is performed, in which three ONUs with transmission distances of 25, 50, and 100 km are assigned with different subcarriers, respectively. By using distance-adaptive bandwidth allocation technique, an OFDM signal of 34.5 Gb/s is successfully delivered to the ONUs with a bit error ratio (BER) lower than 2 × 10(-3).

Compact tunable silicon photonic differential-equation solver for general linear time-invariant systems.

We propose and experimentally demonstrate an all-optical temporal differential-equation solver that can be used to solve ordinary differential equations (ODEs) characterizing general linear time-invariant (LTI) systems. The photonic device implemented by an add-drop microring resonator (MRR) with two tunable interferometric couplers is monolithically integrated on a silicon-on-insulator (SOI) wafer with a compact footprint of ~60 µm × 120 µm. By thermally tuning the phase shifts along the bus arms of the two interferometric couplers, the proposed device is capable of solving first-order ODEs with two variable coefficients. The operation principle is theoretically analyzed, and system testing of solving ODE with tunable coefficients is carried out for 10-Gb/s optical Gaussian-like pulses. The experimental results verify the effectiveness of the fabricated device as a tunable photonic ODE solver.

Anatomy-based inverse planning dose optimization in HDR prostate implant: a toxicity study.

BACKGROUND AND PURPOSE: The aim of this study is to evaluate the acute and late complications in patients who have received HDR implant boost using inverse planning, and to determine dose volume correlations. PATIENTS AND METHODS: Between September 1999 and October 2002, 44 patients with locally advanced prostate cancer (PSA>/=10 ng/ml, and/or Gleason score>/=7, and/or Stage T2c or higher) were treated with 40-45 Gy external pelvic field followed by 2--3 fraction of inverse-planned HDR implant boost (6--9.5 Gy /fraction). Median follow-up time was 1.7 years with 81.8% of patients who had at least 12 months of follow up (range 8.6--42.5. Acute and late morbidity data were collected and graded according to RTOG criteria. Questionnaires were used to collect prostate related measures of quality of life, and international prostate symptom score (IPSS) before and after treatment. Dose-volume histograms for prostate, urethra, bladder, penis bulb and rectum were analyzed. RESULTS: The median patient age was 64 years. Of these, 32% were in the high risk group, and 61% in the intermediate risk group. 3 patients (7%) had no adverse prognostic factors. A single grade 3 GU acute toxicity was reported but no grade 3--4 acute GI toxicity. No grade 3--4 late GU or GI toxicity was reported. Acute (late) grade 2 urinary and rectal symptoms were reported in 31.8 (11.4%) and 4.6% (4.6%) of patients, respectively. A trend for predicting acute GU toxicity is seen for total HDR dose of more than 18 Gy (OR=3.6, 95%CI=[0.96--13.5], P=0.058). The evolution of toxicity is presented for acute and late GU/GI toxicity. Erectile dysfunction occurs in approximately 27% of patients who were not on hormonal deprivation, but may be taking sildenafil. The IPSS peaked on averaged 6 weeks post-implant and returned to the baseline at a median of 6 months. CONCLUSIONS: Inverse-planned HDR brachytherapy is a viable option to deliver higher dose to the prostate as a boost without increasing GU or rectal complication. Further HDR dose escalation to the prostate is feasible.