Drug utilisation in medical intensive care unit: a retrospective analysis from a tertiary care teaching hospital

Background: The World Health Organisation has defined drug utilization study as “the marketing, distribution, prescription and use of drugs in a society, with special emphasis on the resulting medical, social, and economic consequences. The objective was to evaluate drug utilization pattern in medical intensive care unit (MICU) in a tertiary care teaching hospital.Methods: A retrospective observational study was conducted in MICU for adult patients admitted from October to December 2013. Data collected was analysed for demographics, indication, duration of stay, World Health Organisation (WHO) prescribing indicators including anatomical therapeutic chemical classification and defined daily dose (DDD).Results: A six hundred encounters from 63 male and 44 female patients with a mean age of 60.88±16.87 were studied. Average duration of stay was 5.61±3.88 days. The common indications for admission were dyspnoea 20 (18.69%), upper gastrointestinal bleed 16 (14.95%), cerebrovascular accident 14 (13.08%) and sepsis 13 (12.15%). Total number of drugs prescribed was 246. Total drug encounters were 7695. Average number of drugs per encounter was 12.83. Percentage of drugs prescribed by generic name was 38.21%, 44.7% and 40.65% of the drugs were prescribed from National and WHO essential medicine list respectively. Among the drugs prescribed 65.44%, 32.93% and 17.48% were oral, injectable and fixed dose combination preparations respectively. Percentage of encounters resulting in prescription of an antibiotic and an injection were 59% and 85.83% respectively. The most commonly prescribed drugs were pantoprazole (100%), human regular insulin (52.83%), piperacillin + tazobactam (45%) and ceftriaxone (38%). Their DDD/100 bed days were found to be 83.79, 12.78, 12.50, and 17.81 respectively.Conclusions: Overall the prescribing pattern seems to be rational but may be further strengthened by increasing generic drug prescription, judicious use of pantoprazole and periodic longitudinal surveillance studies

Correlation of microstructure and mechanical properties with ultrasonic velocity in the Ni-based superalloy Inconel 625

Inconel 625 tubes are used extensively in ammonia cracker units of heavy-water plants. During service, the alloy is exposed to temperature close to 873 K for a prolonged period (about 60 000 h), leading to substantial decrease in ductility and toughness of the alloy due to heavy intragranular and intergranular precipitation. Service-exposed Inconel 625 material (873 K for about 60 000 h) was given post-service ageing treatments at different temperatures (923, 1023 and 1123K) up to 500 h. These heat treatments altered the microstructure, which in turn had an influence upon both the tensile properties and the ultrasonic velocity. The alloy that had seen service was solution annealed at 1423 K for 0.5 h followed by ageing at different temperatures (923 and 1123 K) and the influence of these heat treatments on changes in microstructures and in turn their effect on room-temperature tensile properties and ultrasonic velocity have been studied. The present study aims at establishing the correlation between room-temperature tensile properties and ultrasonic velocity with the microstructural changes that occurred during ageing treatments in Ni-based superalloy Inconel 625. For the first time, the present authors have demonstrated the influence of various precipitates, such as intermetallic phases γ", Ni2(Cr, Mo) and δ, and grain-boundary carbides, on the correlation of yield strength and ultrasonic velocity

Comprehensive microstructural characterization in modified 9Cr-1Mo ferritic steel by ultrasonic measurements

Modified 9Cr-1Mo ferritic steel (T91/P91) has been subjected to a series of heat treatments consisting of soaking for 5 minutes at the selected temperatures, starting from the α-phase region (1073 K) to the γ+δ-phase region (1623 K), followed by oil quenching. Hardness measurements, microstructural features, and grain-size measurements by the linear-intercept method have been used for correlating them with the ultrasonic parameters. Ultrasonic velocity and attenuation measurements, and spectral analysis of the first backwall echo have been used for characterization of the microstructures obtained by various heat treatments. As the soaking temperature increased above Ac1, the ultrasonic velocity decreased because of the increase in the volume fraction of martensite in the structure. There were sharp changes in the ultrasonic velocities corresponding to the two critical temperatures, Ac1 and Ac3. Ultrasonic longitudinal- and shear-wave velocities were found to be useful in identifying the Ac1 and Ac3 temperatures and for the determination of hardness in the intercritical region. However, ultrasonic attenuation and spectral analysis of the first backwall echo were found to be useful to characterize the variation in the prior-austenitic grain size and formation of δ ferrite above the Ac4 temperature. The scattering coefficients have been experimentally determined for various microstructures and compared with the theoretically calculated value of the scattering coefficients for iron reported in literature

Imaging of modified 9Cr-1Mo ferritic steel weldment via ultrasonic velocity measurements

Ultrasonic velocity measurements have been carried out across the weld line in two perpendicular sections of modified 9Cr-1Mo ferritic steel weldments, in the as welded and post-weld heat treated (PWHT) conditions. The ultrasonic velocity plot is correlated with the weld profile in both the sections and with the associated microstructural features in different regions of the weldments for the two conditions investigated. The present study reveals that the weld profile can be imaged and the adequacy of the PWHT can also be assessed in modified 9Cr-1Mo ferritic steel weldments using ultrasonic velocity measurements

Characterisation of long term aging behaviour of 9Cr-1Mo ferritic steel using ultrasonic velocity

The measurement of ultrasonic velocity of 9Cr-1Mo ferritic steel thermally aged at 793 and 873 K exhibited four distinct regimes in the variation of ultrasonic velocity with aging time. These different regimes have been correlated with the progressive evolution and coarsening of precipitate microstructure studied using TEM and microhardness measurements. The study revealed that ultrasonic velocity can be used to examine the secondary precipitation in the steel and the use of this technique as such can be extended to the health assessment of a component during service

Influence of thermal ageing and creep on ultrasonic velocity in 9Cr-1Mo ferritic steel

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Characterization of microstructures in Inconel 625 using X-ray diffraction peak broadening and lattice parameter measurements

This study demonstrates that, three parameters which are microstrain, lattice parameter and crystallite size, obtained from X-ray diffraction line profile analysis, can be used in a complementary way to study the precipitation/dissolution of various intermetallics and carbides in nickel base superalloy Inconel 625, without extracting the precipitates from the matrix