Evaluation of the Diagnostic Sensitivity of Digital Vibration Sensors Based on Capacitive MEMS Accelerometers.

In recent years, there has been an increasing use of digital vibration sensors that are based on capacitive MEMS accelerometers for machine vibration monitoring and diagnostics. These sensors simplify the design of monitoring and diagnostic systems, thus reducing implementation costs. However, it is important to understand how effective these digital sensors are in detecting rolling bearing faults. This article describes a method for determining the diagnostic sensitivity of diagnostic parameters provided by commercially available vibration sensors based on MEMS accelerometers. Experimental tests were conducted in laboratory conditions, during which vibrations from 11 healthy and faulty rolling bearings were measured using two commercial vibration sensors based on MEMS accelerometers and a piezoelectric accelerometer as a reference sensor. The results showed that the diagnostic sensitivity of the parameters depends on the upper-frequency band limit of the sensors, and the parameters most sensitive to the typical fatigue faults of rolling bearings are the peak and peak-to-peak amplitudes of vibration acceleration. Despite having a lower upper-frequency range compared to the piezoelectric accelerometer, the commercial vibration sensors were found to be sensitive to rolling bearing faults and can be successfully used in continuous monitoring and diagnostics systems for machines.

Resource utilization before and during infliximab therapy in patients with inflammatory bowel disease.

OBJECTIVE: Although Remicade (infliximab) is costly relative to non-biologic therapy, its impact on healthcare resource utilization and mucosal healing may make it a cost-effective option. This study aimed to compare gastrointestinal (GI)-related healthcare resource utilization and severity of mucosal damage before and during infliximab therapy in Crohn's disease (CD) or ulcerative colitis (UC) patients. METHODS: A retrospective chart review was conducted at 14 gastroenterology practices from across the country, which varied in practice sizes and types. Patients were aged ≥18 years, diagnosed with CD or UC, and had an infliximab index date between January 1, 2005 and September 30, 2007. GI-related utilization 12 months before and 12 months after the index date was compared. Endoscopic disease severity was categorized based on blinded review of abstracted reports. RESULTS: Results from 268 patients indicated significantly lower rates of surgery (29.7% to 9.9%, p < 0.0001, CD; 24.4% to 12.8%, p = 0.042, UC) and colonoscopy (54.4% to 17.6%, p < 0.0001, CD; 50.0% to 22.1%, p = 0.0007, UC) during infliximab therapy. The rates of hospitalizations in UC (15.1% to 3.5%, p = 0.0124) and radiology assessments in CD (23.1% to 10.4%, p = 0.006) also decreased. Based on severity data from 183 procedures, greater proportions of patients had normal or mild ratings during infliximab treatment compared with pre-treatment. LIMITATIONS: This retrospective descriptive study is limited by the type and quantity of information available in patient charts from 14 gastroenterology clinics during the first year of infliximab treatment. In addition, the number of patients with pre-treatment and post-treatment disease severity information was too small to make comparisons among disease severity groups. Further information about the severity of disease and the extent of mucosal healing could be helpful in determining the effect of therapy on resource utilization in future research. CONCLUSIONS: GI-related resource utilization was significantly lower and attenuation of mucosal damage severity was observed during infliximab treatment compared with the pre-treatment period.

Stability of infliximab dosing in inflammatory bowel disease: results from a multicenter US chart review.

OBJECTIVE: Infliximab dosing for inflammatory bowel disease (IBD) is based on patient weight and treatment response. Understanding dosing patterns may provide insight into treatment response and predictability of treatment cost. The purpose of this medical record review was to assess dose and dose frequency of infliximab maintenance treatment in patients with IBD using patient chart data. METHODS: A retrospective chart review was conducted at 14 community gastroenterology clinics (GI clinics). Patients were aged ≥18 years, diagnosed with Crohn's disease (CD) or ulcerative colitis (UC), and had a first infliximab administration (index date) between January 1, 2005 and September 30, 2007. At least 24 months of continuous data availability were required with dosing data collected for 12 months after initiation of infliximab therapy. Patients with biologic use and/or participation in an IBD clinical trial within 12 months before the index date were excluded. RESULTS: Charts from 182 CD patients and 86 UC patients were analyzed. About half of the patients were female. Over 90% of patients initiated treatment with infliximab 5 mg/kg. Among CD patients and UC patients, respectively, 79% and 61% continued receiving this dose for maintenance therapy at stable intervals. LIMITATIONS: This retrospective descriptive study is limited by the type and quantity of information available in patient charts from 14 GI clinics during the first year of infliximab treatment. Further, non-anti-tumor necrosis factor medication data were intermittently collected in some charts and, therefore, did not allow for analysis. CONCLUSIONS: Weight-based dosing and, presumably, patient response enabled providers to find the effective infliximab dose for IBD patients. The maintenance dose and administration frequency remained stable during the initial year.