Band 1, Heft 3

Respiratory tract infection increases the risk of secondary bacterial infection and causes mortality. Despite advances in the field of targeted molecular diagnostics, there are still failed attempts in identifying a valid causative etiological agent in a large proportion of respiratory tract infections. To date, a comprehensive list of human respiratory infection-associated eukaryotic viruses has been identified. However, there has been little progress towards the characterisation of the viruses that infect bacteria (phages), which are capable of mediating the transfer of virulence genes into non-pathogenic bacterial species to cause respiratory tract infections. With the advent of next-generation-sequencing, the application of an unbiased comparative metagenomic survey on the viral communities within the human respiratory tract may reveal to us how the phage virome changes between healthy individuals and respiratory tract infection patients. With this useful information, it will be feasible to develop an alternative phage-based diagnostic panel for respiratory tract infections. The review herein presents the current status of human airway microbiome research and highlights potential gaps which can be translated into research possibilities for future work on respiratory tract infection diagnosis.

Exercise induced bronchoconstriction (EIB) may complicate childhood asthma. Leukotriene receptor antagonists (LTRAs), such as montelukast, may be beneficial in protecting against EIB. Our aim was to systematically review the role of LTRAs in the treatment of asthmas complicated by exercise induced bronchoconstriction and to assess various clinical factors which may influence the therapeutic outcome. Electronic searches were performed in the following databases: PubMed, CENTRAL, and the US National Institutes of Health Clinical Trial database. Following selection according to clearly defined inclusion and exclusion criteria and in accordance with the PRISMA statement; 5 double-blind, randomized, placebo-controlled trials of montelukast as monotherapy or add-on therapy in childhood asthma and 2 review articles were analysed in this systematic review. Treatment with LTRAs provides protection from EIB, when used as both monotherapy and add-on therapy. However, disease variables and aetiological factors may impact on the extent of clinical improvement. Genetic variability may influence leukotriene production and subsequent response to LTRAs. This issue could be addressed in further studies.

Background: Checklists have been shown to improve performance of complex, error-prone processes. To develop a checklist with potential to reduce the likelihood of diagnostic error for patients presenting to the Emergency Room (ER) with undiagnosed conditions. Methods: Participants included 15 staff ER physicians working in two large academic centers. A rapid cycle design and evaluation process was used to develop a general checklist for high-risk situations vulnerable to diagnostic error. Physicians used the general checklists and a set of symptom-specific checklists for a period of 2 months. We conducted a mixed methods evaluation that included interviews regarding user perceptions and quantitative assessment of resource utilization before and after checklist use. Results: A general checklist was developed iteratively by obtaining feedback from users and subject matter experts, and was trialed along with a set of specific checklists in the ER. Both the general and the symptom-specific checklists were judged to be helpful, with a slight preference for using symptom-specific lists. Checklist use commonly prompted consideration of additional diagnostic possibilities, changed the working diagnosis in approximately 10% of cases, and anecdotally was thought to be helpful in avoiding diagnostic errors. Checklist use was prompted by a variety of different factors, not just diagnostic uncertainty. None of the physicians used the checklists in collaboration with the patient, despite being encouraged to do so. Checklist use did not prompt large changes in test ordering or consultation. Conclusions: In the ER setting, checklists for diagnosis are helpful in considering additional diagnostic possibilities, thus having potential to prevent diagnostic errors. Inconsistent usage and using the checklists privately, instead of with the patient, are factors that may detract from obtaining maximum benefit. Further research is needed to optimize checklists for use in the ER, determine how to increase usage, to evaluate the impact of checklist utilization on error rates and patient outcomes, to determine how checklist usage affects test ordering and consultation, and to compare checklists generally with other approaches to reduce diagnostic error.

Background : Patients with chronic rheumatic heart disease (CRHD) have concomitant coronary artery disease (CAD), but the model to detect coexistent coronary artery stenosis prior to surgery has not been validated. Our study investigated whether the Framingham Risk Score (FRS) is a valid predictor of CAD in patients undergoing surgery for CRHD. Methods: A total of 989 rheumatic patients were enrolled between 2005 and 2010. They were subdivided into two groups according to coronary angiography (CAG) results to identify potential factors in the development of CAD. Finally, all patients were assessed using the FRS to examine the association between the 10-year cardiovascular disease (CVD) risk and CAD. Results: There were statistically significant inter-group differences in terms of age, sex, smoking, hypertension, bypass surgery and cardiac function in the New York Heart Association (NYHA) classification status (p<0.05). We showed that the FRS had high accuracy in predicting CAD in female and male patients with CRHD. In the male group, the area under the curve (AUC) for predicting CAD was 0.904, with a specificity of 90.3% and sensitivity of 76.1%. In the female group, the AUC for predicting CAD was 0.924, with a specificity of 77.5% and sensitivity of 90.9%, respectively. With a cut-off point of a 10-year CVD risk of 12.5 (%) in the male group and a 10-year CVD risk of 2.5 (%) in the female group, the FRS identified 746 low-risk patients, including 11 (4.3%) with CAD in the male group and 4 (0.8%) with CAD in the female group. None of the patients needed an indication for coronary artery bypass grafting (CABG). Conclusions: The FRS model can accurately predict the prevalence of significant CAD and can reliably identify low-risk patients in whom routine pre-surgical angiography could be avoided.

Background: Laboratory tests in hospitals are among the most important diagnostic tools for medical decision making at the Emergency Department. They are often ordered as part of extended test panels, which, although helpful and convenient for doctors, may lead to overuse of tests and overdiagnosis. To improve the ordering process, we investigated which laboratory tests are essential for optimal decision making at the Emergency Department of our hospital. Methods: Forty-nine doctors regularly involved with the Emergency Department filled in a questionnaire asking for their opinions on laboratory test ordering and use. Results: A limited number of laboratory tests are considered indispensable for the Emergency Department: CRP and leukocytes, urea and creatinin, sodium and potassium, and haemoglobin. Glucose and troponin should probably also be included in this list, but were not mentioned as glucose is measured using portable point-of-care devices in our hospital, while cardiac patients are referred directly to the cardiac care unit. Conclusions: Only a limited number of laboratory tests are essential for early medical decision making at the Emergency Department. Ordering facilities should be arranged such that these tests are permanently available, easy to order, and performed with short turnaround times. Test panels for the ED should incorporate these essential tests, with additional other tests so as to prevent essential tests from being forgotten, maintain convenience for doctors and promote sensible and effective use of diagnostic testing. The outcome of these conflicting aims is a compromise, as is discussed.

Posing a question can introduce a powerful bias into the diagnostic process. A clinical case is presented to demonstrate how a colleague’s diagnostic question can focus the clinicians’ attention on one detail, distracting and blinding them even to the most obvious and important clinical findings. This “inattentional blindness” is similar to the phenomenon demonstrated by Simons in the famous “invisible gorilla” psychological experiment. As much as practical, clinicians should attempt to assess referred patients independently before considering previous clinical information; including the question/s they were asked.