Probiotics in the prevention of clinical manifestations of common infectious diseases in children and in the elderly

Infectious diseases put an enormous burden on both children and the elderly in the forms of respiratory, gastrointestinal and oral infections. There is evidence suggesting that specific probiotics may be antagonistic to pathogens and may enhance the immune system, but the clinical evidence is still too sparce to make general conclusions on the disease-preventive effects of probiotics. This thesis, consisting of four independent, double-blind, placebo-controlled clinical trials, investigated whether Lactobacillus GG (LGG) or a specific probiotic combination containing LGG would reduce the risk of common infections or the prevalence of pathogens in healthy and infection-prone children and in independent and institutionalised elderly people. In healthy day-care children, the 7-month consumption of probiotic milk containing Lactobacillus GG appeared to postpone the first acute respiratory infection (ARI) by one week (p=0.03, adjusted p=0.16), and to reduce complicated infections (39% vs. 47%, p<0.05, adjusted p=0.13), as well as the need for antibiotic treatment (44% vs. 54%, p=0.03, adjusted p=0.08) and day-care absences (4.9 vs. 5.8 days, p=0.03, adjusted p=0.09) compared to the placebo milk. In infection-prone children, the 6-month consumption of a combination of four probiotic bacteria (LGG, L. rhamnosus LC705, Propionibacterium freudenreichii JS, Bifidobacterium breve 99) taken in capsules appeared to reduce recurrent ARIs (72% vs. 82%, p<0.05; adjusted p=0.06), and the effect was particularly noticeable in a subgroup of children with allergic diseases (12% vs. 33%, p=0.03), although no effect on the presence of nasopharyngeal rhinovirus or enterovirus was seen. The 5-month consumption of the same probiotic combination did not show any beneficial effects on the respiratory infections in frail, institutionalised elderly subjects. In healthy children receiving Lactobacillus GG, the reduction in complications resulted in a marginal reduction in the occurrence of acute otitis media (AOM) (31% vs. 39%, p=0.08; adjusted p=0.19), and the postponement of the first AOM episode by 12 days (p=0.04; adjusted p=0.09). However, in otitis-prone children, a probiotic combination did not reduce the occurrence of AOM or the total prevalence of common AOM pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis), except in the case of children with allergic diseases, in whom probiotics reduced recurrent AOM episodes (0% vs. 14%, p=0.03). In addition, interaction between probiotics and bacterial carriage was seen: probiot-ics reduced AOM in children who did not carry any bacterial pathogens (63% vs. 83%), but the effect was the reverse in children carrying bacteria in the nasopharynx (74% vs 62%) (p<0.05). Long-term probiotic treatment, either LGG given in milk to healthy children for 7 months or a combination of probiotics given in capsules to institutionalised elderly subjects for 5 months, did not reduce the occurrence of acute diarrhoea. However, when the probiotic combination (LGG, L. rhamnosus LC705, Propionibacterium JS) was given in cheese to independent elderly subjects for 4 months, the oral carriage of high Candida counts was reduced in the probiotic group vs. the placebo group (21% vs. 34%, p=0.01, adjusted p=0.004). The risk of hyposalivation was also reduced in the probiotic group (p=0.05). In conclusion, probiotics appear to slightly alleviate the severity of infections by postponing their appearance, by reducing complications and the need for antimicrobial treatments. In addition, they appear to prevent recurrent infections in certain subgroups of children, such as in infection-prone children with allergic diseases. Alleviating ARI by probiotics may lead to a marginal reduction in the occurrence of AOM in healthy children but not in infection-prone children with disturbed nasopharyngeal microbiota. On the basis of these results it could be supposed that Lactobacillus GG or a specific combination containing LGG are effective against viral but not against bacterial otitis, and the mechanism is probably mediated through the stimulation of the immune system. A specific probiotic combination does not reduce respiratory infections in frail elderly subjects. Acute diarrhoea, either in children or in the elderly, is not prevented by the continuous, long-term consumption of probiotics, but the consumption of a specific probiotic combination in a food matrix is beneficial to the oral health of the elderly, through the reduction of the carriage of Candida.

Clinical reasoning: The relative contribution of identification, interpretation and hypothesis errors to misdiagnosis

The aim of this study was to identify and describe the types of errors in clinical reasoning that contribute to poor diagnostic performance at different levels of medical training and experience. Three cohorts of subjects, second- and fourth- (final) year medical students and a group of general practitioners, completed a set of clinical reasoning problems. The responses of those whose scores fell below the 25th centile were analysed to establish the stage of the clinical reasoning process - identification of relevant information, interpretation or hypothesis generation - at which most errors occurred and whether this was dependent on problem difficulty and level of medical experience. Results indicate that hypothesis errors decrease as expertise increases but that identification and interpretation errors increase. This may be due to inappropriate use of pattern recognition or to failure of the knowledge base. Furthermore, although hypothesis errors increased in line with problem difficulty, identification and interpretation errors decreased. A possible explanation is that as problem difficulty increases, subjects at all levels of expertise are less able to differentiate between relevant and irrelevant clinical features and so give equal consideration to all information contained within a case. It is concluded that the development of clinical reasoning in medical students throughout the course of their pre-clinical and clinical education may be enhanced by both an analysis of the clinical reasoning process and a specific focus on each of the stages at which errors commonly occur.

The association between student characteristics and the development of clinical reasoning in a graduate-entry, PBL medical programme

This study sought to assess the extent to which the entry characteristics of students in a graduate-entry medical programme predict the subsequent development of clinical reasoning ability. Subjects comprised 290 students voluntarily recruited from three successive cohorts of the University of Queensland's MBBS Programme. Clinical reasoning was measured once a year over a period of three years using two methods, a set of 10 Clinical Reasoning Problems (CRPs) and the Diagnostic Thinking Inventory (DTI). Data on gender, age at entry into the programme, nature of primary degree, scores on selection criteria (written examination plus interview) and academic performance in the first two years of the programme were recorded for each student, and their association with clinical reasoning skill analysed using univariate and multivariate analysis. Univariate analysis indicated significant associations between CRP score, gender and primary degree with a significant but small association between DTI and interview score. Stage of progression through the programme was also an important predictor of performance on both indicators. Subsequent multivariate analysis suggested that female gender is a positive predictor of CRP score independently of the nature of a subject's primary degree and stage of progression through the programme, although these latter two variables are interdependent. Positive predictors of clinical reasoning skill are stage of progression through the MBBS programme, female gender and interview score. Although the nature of a student's primary degree is important in the early years of the programme, evidence suggests that by graduation differences between students' clinical reasoning skill due to this factor have been resolved.

The clinical reasoning characteristics of diagnostic experts

The aim of this study was to identify and describe the clinical reasoning characteristics of diagnostic experts. A group of 21 experienced general practitioners were asked to complete the Diagnostic Thinking Inventory (DTI) and a set of 10 clinical reasoning problems (CRPs) to evaluate their clinical reasoning. Both the DTI and the CRPs were scored, and the CRP response patterns of each GP examined in terms of the number and type of errors contained in them. Analysis of these data showed that six GPs were able to reach the correct diagnosis using significantly less clinical information than their colleagues. These GPs also made significantly fewer interpretation errors but scored lower on both the DTI and the CRPs. Additionally, this analysis showed that more than 20% of misdiagnoses occurred despite no errors being made in the identification and interpretation of relevant clinical information. These results indicate that these six GPs diagnose efficiently, effectively and accurately using relatively few clinical data and can therefore be classified as diagnostic experts. They also indicate that a major cause of misdiagnoses is failure to properly integrate clinical data. We suggest that increased emphasis on this step in the reasoning process should prove beneficial to the development of clinical reasoning skill in undergraduate medical students.

Promoting and providing expert guidance in work-intensive clinical settings

This paper discusses how expert guidance can be best provided in work intensive clinical settings. The adequacy for supporting learning in the clinical practicum for health care disciplines is often complicated by the intensive work practices in healthcare settings. Often, clinicians' work is so intense that the scope for providing close guidance for students is quite restricted. The case advanced here draws on a range of empirical work to propose how clinician-student interactions might be optimized through the provision of a clinical ccn guided learning such as demonstrating and role-modeling. These roles can contribute in essential ways to the development of learning environments where clinicians have the opportunity to facilitate the learning of others as part of their workload, and without being burdened by the requirements of teaching and assessment processes. It differs from other approaches because although clinicians partner students and provide feedback to them, clinicians are not expected to formally assess or award a grade for student performance. Assessment and remedial action, when required, is undertaken by the role of a designated clinical supervisor qualified to perform such activities. © 2010 Springer Science+Business Media B.V.

Interprofessional education in clinical practice: Not a single vaccine

In increasingly complex health service environments, the quality of teamwork and co-operation between doctors, nurses and allied health professionals, is 'under the microscope'. Interprofessional education (IPE), a process whereby health professionals learn 'from, with and about each other', is advocated as a response to widespread calls for improved communication and collaboration between healthcare professionals. Although there is much that is commendable in IPE, the authors caution that the benefits may be overstated if too much is attributed to, or expected of, IPE activities. The authors propose that clarity is required around what can realistically be achieved. Furthermore, engagement with clinicians in the clinical practice setting who are instrumental in assisting students make sense of their knowledge through practice, is imperative for sustainable outcomes. © AHHA 2010.

The mini clinical evaluation exercise (mini-CEX) for assessing clinical performance of international medical graduates

Objective: To evaluate the feasibility, reliability and acceptability of the mini clinical evaluation exercise (mini-CEX) for performance assessment among international medical graduates (IMGs). Design, setting and participants: Observational study of 209 patient encounters involving 28 IMGs and 35 examiners at three metropolitan teaching hospitals in New South Wales, Victoria and Queensland, September-December 2006. Main outcome measures: The reliability of the mini-CEX was estimated using generatisability (G) analysis, and its acceptability was evaluated by a written survey of the examiners and IMGs. Results: The G coefficient for eight encounters was 0.88, suggesting that the reliability of the mini-CEX was 0.90 for 10 encounters. Almost half of the IMGs (7/16) and most examiners (14/18) were satisfied with the mini-CEX as a learning tool. Most of the IMGs and examiners enjoyed the immediate feedback, which is a strong component of the tool. Conclusion: The mini-CEX is a reliable tool for performance assessment of IMGs, and is acceptable to and well received by both learners and supervisors.

Clinical teaching: Maintaining an educational role for doctors in the new health care environment

Context and objectives: Good clinical teaching is central to medical education but there is concern about maintaining this in contemporary, pressured health care environments. This paper aims to demonstrate that good clinical practice is at the heart of good clinical teaching. Methods: Seven roles are used as a framework for analysing good clinical teaching. The roles are medical expert, communicator, collaborator, manager, advocate, scholar and professional. Results: The analysis of clinical teaching and clinical practice demonstrates that they are closely linked. As experts, clinical teachers are involved in research, information retrieval and sharing of knowledge or teaching. Good communication with trainees, patients and colleagues defines teaching excellence. Clinicians can 'teach' collaboration by acting as role models and by encouraging learners to understand the responsibilities of other health professionals. As managers, clinicians can apply their skills to the effective management of learning resources. Similarly skills as advocates at the individual, community and population level can be passed on in educational encounters. The clinicians' responsibilities as scholars are most readily applied to teaching activities. Clinicians have clear roles in taking scholarly approaches to their practice and demonstrating them to others. Conclusion: Good clinical teaching is concerned with providing role models for good practice, making good practice visible and explaining it to trainees. This is the very basis of clinicians as professionals, the seventh role, and should be the foundation for the further development of clinicians as excellent clinical teachers.

In-training assessment - Its potential in enhancing clinical teaching

Context In-training assessment (ITA) has established its place alongside formative and summative assessment at both the undergraduate and postgraduate level. In this paper the authors aimed to identify those characteristics of ITA that could enhance clinical teaching. Methods A literature review and discussions by an expert working group at the Ninth Cambridge Conference identified the aspects of ITA that could enhance clinical teaching. Results The features of ITA identified included defining the specific benefits to the learner, teacher and institution, and highlighting the patient as the context for ITA and clinical teaching. The ‘mapping’ of a learner’s progress towards the clinical teaching objectives by using multiple assessments over time, by multiple observers in both a systematic and opportunistic way correlates with the incremental nature of reaching clinical competence. Conclusions The importance of ITA based on both direct and indirect evidence of what the learner actually does in the real clinical setting is emphasized. Particular attention is given to addressing concerns in the more controversial areas of assessor training, ratings and documentation for ITA. Areas for future research are also identified.

Evolution of isolated streamwise vortices in the late stages of boundary layer transition

Experiments were conducted with two, smooth hills, lying well within the boundary layer over a flat plate mounted in a wind tunnel. One hill was shallow, with peak height 1.5 mm and width 50 mm; the other, steep, 3 mm high and 30 mm wide. Since the hills occupied one-half of the tunnel span, streamwise vorticity formed near the hills' edge. At a freestream speed of 3.5 m/s, streaks formed with inflectional wall-normal and spanwise velocity profiles but without effecting transition. Transition, observed at 7.5 m/s, took different routes with the two hills. With the steep hill, streamwise velocity signals exhibited the passage of a wave packet which intensified before breakdown to turbulence. With the shallow hill there was a broad range of frequencies present immediately downstream of the hill. These fluctuations grew continuously and transition occurred within a shorter distance. Since the size of the streamwise vorticity generated at the hill edge is of the order of the hill height, the shallow hill generates vorticity closer to the wall and supports an earlier transition, whereas the steep hill creates a thicker vortex and associated streaks which exhibit oscillations due to their own instability as an additional precursor stage before transition.