Temporal stability of objective structured clinical exams: a longitudinal study employing item response theory

Background

The objective structure clinical examination (OSCE) has been used since the early 1970s for assessing clinical competence. There are very few studies that have examined the psychometric stability of the stations that are used repeatedly with different samples. The purpose of the present study was to assess the stability of objective structured clinical exams (OSCEs) employing the same stations used over time but with a different sample of candidates, SPs, and examiners.

Methods

At Time 1, 191 candidates and at Time 2 (one year apart), 236 candidates participated in a 10-station OSCE; 6 of the same stations were used in both years. Generalizability analyses (Ep²) were conducted. Employing item response analyses, test characteristic curves (TCC) were derived for each of the 6 stations for a 2-parameter model. The TCCs were compared across the two years, Time 1 and 2.

Results

The Ep² of the OSCEs exceeded.70. Standardized thetas (θ) and discriminations were equivalent for the same station across the two year period indicating equivalent TCCs for a 2-parameter model.

Conclusion

The 6 OSCE stations used by the AIMG program over two years have adequate internal consistency reliability, stable generalizability (Ep²) and equivalent test characteristics. The process of assessment employed for IMG’s are stable OSCE stations that may be used several times over without compromising psychometric properties.With careful security, high-stakes OSCEs may use the same stations that have high internal consistency and generalizability repeatedly as the psychometric properties are stable over several years with different samples of candidates.

     

A large unilocular mucinous cystadenoma in third trimester of pregnancy

Ovarian malignancy is the second most common gynaecological malignancy diagnosed during pregnancy. A grand multipara, aged 30 years presented with gestational amenorrhea with abdominal discomfort and breathlessness for last 15 days. Sonographic examination demonstrated a huge, unilocular ovarian cyst and an alive fetus of about 30 weeks gestation. Intraoperative findings were huge left ovarian cyst (42x40x20 cm) with straw coloured mucinous fluid. Left salpingo-oophorectomy was performed followed by peritoneal washings and omental biopsy. Histopathology revealed mucinous cystadenomas with inflammatory changes in omentum and no malignant cells in peritoneal washings. She delivered vaginally a female baby of 3.5 kg at 38 weeks with good Apgar score.     

An outbreak of Burkholderia cepacia associated with contamination of albuterol and nasal spray

BACKGROUND: Species within the Burkholderia cepacia complex (Bcc) can contaminate medications and disinfectants and cause severe pneumonia in critically ill patients or persons with cystic fibrosis. In March 2004, we investigated a hospital outbreak of Bcc possibly associated with a contaminated nasal spray. METHODS: We conducted a matched case-control study, environmental sampling, and observations of infection control practices. Case patients had infection or colonization with Bcc, and control patients had sputum culture not yielding Bcc. Isolates from patients and environmental samples were compared by pulsed-field gel electrophoresis (PFGE). RESULTS: Bcc was recovered from sputum in 18 patients. Compared with matched control patients (n = 18), case patients were more likely to be receiving mechanical ventilation (p = 0.01), to have been hospitalized > 6 days (p = 0.01), and to have received antimicrobial treatment within 7 days before sputum collection (p = 0.03). Bcc was cultured from opened, but not unopened, multidose albuterol bottles, a nebulizer attached to a ventilator, and opened and unopened nasal spray bottles from contaminated lots. PFGE showed that isolates from albuterol samples and from patients were indistinguishable but unrelated to the nasal spray strain. Observations revealed improper aseptic techniques during respiratory therapy procedures and inadequate nebulizer cleaning. CONCLUSIONS: Despite a temporal association with use of a contaminated nasal spray, this outbreak was caused by extrinsic contamination of multidose albuterol used for nebulization treatments and lack of adherence to infection control precautions. Implementation and re-enforcement of infection control measures successfully terminated the outbreak.     

Antioxidant constituents from Cotoneaster racemiflora

A new lignan rhamnoside, racemiside (1), has been isolated from the ethyl acetate-soluble fraction of Cotoneaster racemiflora, along with scopoletin (2), 7,8-dimethoxy-6-hydroxycoumarin (3), 3,3′,4′-tri-O-methylellagic acid (4), and cereotagloperoxide (5), reported for the first time from this species. All of them showed profound antioxidative activities in the DPPH assay.