BackgroundPredictive indexes of weaning from mechanical ventilation are often inaccurate. Among the many indexes used in clinical practice, the rapid shallow breathing index is one of the most accurate. We evaluated a new weaning index consisting in the diaphragm thickening fraction (DTF) assessed by ultrasound.MethodsForty-six patients were prospectively enrolled. All patients were ventilated in pressure support through a tracheostomy tube. Patients underwent a spontaneous breathing trial (SBT) when they met all the following criteria: FiO2 < 0.5, PEEP ≤5 cmH2O, PaO2/FiO2 > 200, respiratory rate <30 breaths per minute, absence of fever, alert and cooperative, and hemodynamic stability without vaso-active therapy support. During the trial, the right hemi-diaphragm was visualized in the zone of apposition using a 10-MHz linear ultrasound probe. The patient was then instructed to perform breathing to total lung capacity (TLC) and then exhaling to residual volume (RV). Diaphragm thickness was recorded at TLC and RV, and the DTF was calculated as percentage from the following formula: Thickness at end inspiration - Thickness at end expiration / Thickness at end expiration. Also, the rapid shallow breathing index (RSBI) was calculated. Weaning failure was defined as the inability to maintain spontaneous breathing for at least 48 h, without any form of ventilatory support.ResultsA significant difference between diaphragm thickness at TLC and RV was observed both in patients who succeeded SBT and patients who failed. DTF was significantly different between patients who failed and patients who succeeded SBT. A cutoff value of a DTF >36% was associated with a successful SBT with a sensitivity of 0.82, a specificity of 0.88, a positive predictive value (PPV) of 0.92, and a negative predictive value (NPV) of 0.75. By comparison, RSBI <105 had a sensitivity of 0.93, a specificity of 0.88, a PPV of 0.93, and a NPV of 0.88 for determining SBT success.ConclusionsThis study shows that in our cohort of patients, the assessment of DTF by diaphragm ultrasound may perform similarly to other weaning indexes. If validated by other studies, this method may be used in clinical practice.

Dyspnea is a common symptom in patients admitted to the Emergency Department (ED), and discriminating between cardiogenic and non-cardiogenic dyspnea is often a clinical dilemma. The initial diagnostic work-up may be inaccurate in defining the etiology and the underlying pathophysiology. The aim of this study was to evaluate the diagnostic accuracy and reproducibility of pleural and lung ultrasound (PLUS), performed by emergency physicians at the time of a patient's initial evaluation in the ED, in identifying cardiac causes of acute dyspnea. Between February and July 2007, 56 patients presenting to the ED with acute dyspnea were prospectively enrolled in this study. In all patients, PLUS was performed by emergency physicians with the purpose of identifying the presence of diffuse alveolar-interstitial syndrome (AIS) or pleural effusion. All scans were later reviewed by two other emergency physicians, expert in PLUS and blinded to clinical parameters, who were the ultimate judges of positivity for diffuse AIS and pleural effusion. A random set of 80 recorded scannings were also reviewed by two inexperienced observers to assess inter-observer variability. The entire medical record was independently reviewed by two expert physicians (an emergency medicine physician and a cardiologist) blinded to the ultrasound (US) results, in order to determine whether, for each patient, dyspnea was due to heart failure, or not. Sensitivity, specificity, and positive/negative predictive values were obtained; likelihood ratio (LR) test was used. Cohen's kappa was used to assess inter-observer agreement. The presence of diffuse AIS was highly predictive for cardiogenic dyspnea (sensitivity 93.6%, specificity 84%, positive predictive value 87.9%, negative predictive value 91.3%). On the contrary, US detection of pleural effusion was not helpful in the differential diagnosis (sensitivity 83.9%, specificity 52%, positive predictive value 68.4%, negative predictive value 72.2%). Finally, the coexistence of diffuse AIS and pleural effusion is less accurate than diffuse AIS alone for cardiogenic dyspnea (sensitivity 81.5%, specificity 82.8%, positive predictive value 81.5%, negative predictive value 82.8%). The positive LR was 5.8 for AIS [95% confidence interval (CI) 4.8-7.1] and 1.7 (95% CI 1.2-2.6) for pleural effusion, negative LR resulted 0.1 (95% CI 0.0-0.4) for AIS and 0.3 (95% CI 0.1-0.8) for pleural effusion. Agreement between experienced and inexperienced operators was 92.2% (p < 0.01) and 95% (p < 0.01) for diagnosis of AIS and pleural effusion, respectively. In early evaluation of patients presenting to the ED with dyspnea, PLUS, performed with the purpose of identifying diffuse AIS, may represent an accurate and reproducible bedside tool in discriminating between cardiogenic and non-cardiogenic dyspnea. On the contrary, US detection of pleural effusions does not allow reliable discrimination between different causes of acute dyspnea in unselected ED patients.

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We report the first empirical data showing a significant amount of double conjunction fallacies in physicians' probability judgments concerning prognosis and diagnosis. Our results support the hypothesis that physicians' probability judgments are guided by assessments of evidential impact between diagnostic conditions and clinical signs. Moreover, we show that, contrary to some influential views, double conjunction fallacies represent an experimentally replicable reasoning bias. We discuss how the phenomenon eludes major current accounts of uncertain reasoning in medicine and beyond and how it relates to clinical practice.

The purpose of this study was to assess the management of both hypertension and micro/macroalbuminuria in a cohort of type II diabetic patients. In the first 6 months of the year 2000, 5815 diabetic patients were identified through prescriptions for antidiabetic drugs in our sanitary district (191 568 inhabitants). In all, 65% (3810) of these type II diabetic patients were also given prescriptions for antihypertensive drugs. A total of 400 diabetic patients were randomly selected and 171 entered the study (gender: 94/77 M/F; age: 66.6 7 8 years; diabetes duration: 12 7 9 years): 100 patients (group DT) were treated with antihypertensive drugs and 71 (group DU) were untreated. Blood pressure, urine albumin-to-creatinine ratio (ACR), and glycated haemoglobin were measured in the two groups. A total of 80% (57/71) of DU patients were hypertensive (BPX130/ 85 mmHg). Specifically, 24.4% had diastolic hypertension (BPX85 mmHg) and 79% systolic hypertension (BPX130 mmHg). Only 63% (100/157) of the hypertensive patients were treated with antihypertensive drugs (two drugs/patient on average, range 1-5). In addition, only 13% of the DT patients were adequately controlled (BPo130/85 mmHg), while the others had above target blood pressure levels (14%: 130-139/85-89 mmHg; 40%: 140-159/90-95 mmHg, and 33%X160/ 95 mmHg). Angiotensin converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARB) were included in the antihypertensive medical regimen in 70% of the DT patients (ACE-I: 62%; ARB: 8%; diuretics: 39%; dihydropyridine calcium antagonists: 38%; a-blockers: 20%, b-blockers: 17%; clonidin: 8%; nondihydropyridine calcium antagonists: 5%). Only 33% of type II diabetic patients underwent a screening for microalbuminuria as assessed on clinical records. The same percentage of micro-and macroalbuminuric patients (13.5%) was observed in the DT group, whereas 25% micro vs 3% macro were found in the DU group. In all, 73% of microalbuminuric patients were not on ACE-I/ARB. Hypertensive type II diabetic patients were often left untreated and only a minority of those treated were optimally controlled. The importance of an elevated systolic pressure is underestimated and the number of antihypertensive drugs prescribed insufficient. Screening and treatment of albuminuria are inadequate.

Although error is an integral part of the world of medicine, physicians have always been little inclined to take into account their own mistakes and the extraordinary technological progress observed in the last decades does not seem to have resulted in a significant reduction in the percentage of diagnostic errors. The failure in the reduction in diagnostic errors, notwithstanding the considerable investment in human and economic resources, has paved the way to new strategies which were made available by the development of cognitive psychology, the branch of psychology that aims at understanding the mechanisms of human reasoning. This new approach led us to realize that we are not fully rational agents able to take decisions on the basis of logical and probabilistically appropriate evaluations. In us, two different and mostly independent modes of reasoning coexist: a fast or non-analytical reasoning, which tends to be largely automatic and fast-reactive, and a slow or analytical reasoning, which permits to give rationally founded answers. One of the features of the fast mode of reasoning is the employment of standardized rules, termed ''heuristics.'' Heuristics lead physicians to correct choices in a large percentage of cases. Unfortunately, cases exist wherein the heuristic triggered fails to fit the target problem, so that the fast mode of reasoning can lead us to unreflectively perform actions exposing us and others to variable degrees of risk. Cognitive errors arise as a result of these cases. Our review illustrates how cognitive errors can cause diagnostic problems in clinical practice.

Hypertension is a common manifestation of antiphospholipid syndrome (APS). Antiphospholipid antibodies (aPL) have been described in patients with hypertension secondary to renal artery stenosis (RAS). Twenty-six patients with RAS and 25 patients with severe essential hypertension (diastolic blood pressure > 110 mmHg or > or = 3 hypertensive drugs) were studied and compared to 61 age- and sex-matched healthy subjects. Serum samples were tested for lupus anticoagulant (LA), anticardiolipin (aCL) IgG and IgM, antiprothrombin (aPT) IgG and IgM, anti-beta2glycoprotein 1 (abeta2GP1) IgG and IgM. aPL were negative in all patients with RAS. Two patients with essential hypertension had positive aPL (8%) (LA in one patient confirmed in a second assay and abeta2GP1-IgG in the other patient confirmed one year later together with aCL IgG positivity). Among healthy subjects, one case (1.6%) was found to be positive for LA, aCL IgM, abeta2GP1 IgM, aPT IgG, aPT IgM. In conclusion, the association between RAS and aPL seems to be casual rather than an expression of an elective thrombotic localization ofAPS. The positive finding of aPL in 8% of patients with essential hypertension, a frequency higher than that of the control population, deserves further studies in larger series to better explore the relationship between aPL and hypertension.