OBJECTIVE To assess the efficacy and complications of device occlusion of atrial septal defects in adults, using the Amplatzer septal occluder (ASO). DESIGN A prospective interventional study. ...SETTING Paediatric cardiology departments in two European teaching hospitals. PATIENTS The first 20 patients accepted for atrial septal defect device occlusion, on the basis of transoesophageal echocardiography. Sixteen patients had larger defects with right heart dilatation, while the primary indication for closure in four was a history of early paradoxical embolism. INTERVENTIONS Transcatheter atrial septal defect occlusions performed under transoesophageal echocardiography and fluoroscopic guidance between December 1996 and June 1998. OUTCOME MEASURES Success of deployment of ASO devices, procedure and fluoroscopic times, complications, and symptoms. RESULTS The ASO device was successfully implanted in all 20 patients (14 female), median age 44.2 years, with no complications. Of the 16 patients with right heart dilatation, the median Qp:Qs was 2.5:1. Defects measured 11–22 mm (median 18) on transoesophageal echocardiography, with balloon sized diameter (and device size) of 13–28 mm (median 20). For all 20 patients, the procedure time ranged from 38–78 minutes (median 61), and fluoroscopy 8.4–24.7 minutes (median 15.2). There were residual shunts in three patients at the end of the procedure, which were trivial (⩽ 1 mm) as assessed by transoesophageal echocardiography, and persisted for more than six months in only one patient. Follow up ranged from 0.1–1.5 years (median 0.7). There have been no late complications. CONCLUSIONS The ASO device can be used successfully to close selected oval fossa defects in adults, with minimal procedural morbidity and excellent early results.
Railway Accidents Caused by Human Error Kyriakidis, Miltos; Pak, Kam To; Majumdar, Arnab
Transportation research record,
01/2015, Letnik:
2476, Številka:
1
Journal Article
Recenzirano
Accident investigation and analysis are key to reinforcing and improving railway safety. Many railway accidents have been caused by degraded human performance and human error, and the tasks of train ...drivers and signalers have remained essentially the same. Although new technologies and equipment have gradually reduced railway operation accidents, no investigation has been conducted to investigate whether railway performance shaping factors (R-PSFs), attributed to degraded human performance, have changed or remained constant. Focusing on UK railways, this paper analyzes railway accidents involving human error for the period 1945 to 2012. The purpose of the analysis is twofold: to identify whether the number and type of factors that affect human performance and contribute to human errors have changed during this period and to assess the quality of data collected by investigation reports and to determine whether the collection of such data has evolved and improved. The analysis identifies the number of R-PSFs and their relationship to such variables as responsible personnel, immediate causes, and the time and location of the event. The contribution of those variables to the severity of an accident is calculated. Moreover, any changes in trends and patterns in the number of R-PSFs over time are explored through smoothing techniques of time series analysis. Finally, the quality of the collected data is analyzed with the data quality index. Results show that data investigation and data collection have significantly improved. However, although accident rates have decreased, the average number and type of factors that affect human performance have remained the same.
Both clonidine and ketamine have been found to prolong the action of local anesthetics through a peripheral mechanism. Our study compares the efficacy of a low dose of clonidine or ketamine ...separately added to intravenous regional anesthesia (IVRA) with lidocaine to prevent tourniquet pain.
We conducted a prospective randomized double-blinded study in 45 patients undergoing hand or forearm surgery, with anticipated duration exceeding 1 hour under IVRA. Proximal cuff inflation of a double tourniquet was followed by administration of 40 mL of lidocaine 0.5% and either saline, 1 microg/kg clonidine, or 0.1 mg/kg ketamine. When anesthesia was established, the inflation of the proximal and distal cuff was interchanged. Thereafter, tourniquet pain was rated on a visual analog scale (VAS) every 10 minutes. Intraoperatively, boluses of 25 microg fentanyl were provided for tourniquet pain treatment when required, and total fentanyl consumption was recorded.
Patients receiving plain lidocaine persistently reported the highest pain scores among groups (P <.001) 20 minutes after distal cuff inflation. Differences between the groups with additional treatment were noted 50 minutes after distal cuff inflation and until the end of the observation, with significantly lower VAS ratings (P <.001 to P <.01) in ketamine-treated patients. Total fentanyl consumption was significantly decreased by ketamine (70.00 +/- 25.35 microg) or clonidine (136.67 +/- 39.94 microg) compared with the plain lidocaine group (215.33 +/- 52.33 microg) (P <.001 between all groups).
The addition of clonidine 1 microg/kg or ketamine 0.1 mg/kg to lidocaine for IVRA delays the onset of unbearable tourniquet pain and decreases analgesic consumption for tourniquet pain relief, although ketamine has a more potent effect.
•Naturalistic driving scene annotation was accomplished with crowdsourcing.•12,862 annotations were completed in 1.5days by 200 external workers from 46 countries.•Embedded control questions enhance ...annotation validity and reliability.
A common challenge with processing naturalistic driving data is that humans may need to categorize great volumes of recorded visual information. By means of the online platform CrowdFlower, we investigated the potential of crowdsourcing to categorize driving scene features (i.e., presence of other road users, straight road segments, etc.) at greater scale than a single person or a small team of researchers would be capable of. In total, 200 workers from 46 different countries participated in 1.5days. Validity and reliability were examined, both with and without embedding researcher generated control questions via the CrowdFlower mechanism known as Gold Test Questions (GTQs).
By employing GTQs, we found significantly more valid (accurate) and reliable (consistent) identification of driving scene items from external workers. Specifically, at a small scale CrowdFlower Job of 48 three-second video segments, an accuracy (i.e., relative to the ratings of a confederate researcher) of 91% on items was found with GTQs compared to 78% without. A difference in bias was found, where without GTQs, external workers returned more false positives than with GTQs. At a larger scale CrowdFlower Job making exclusive use of GTQs, 12,862 three-second video segments were released for annotation. Infeasible (and self-defeating) to check the accuracy of each at this scale, a random subset of 1012 categorizations was validated and returned similar levels of accuracy (95%).
In the small scale Job, where full video segments were repeated in triplicate, the percentage of unanimous agreement on the items was found significantly more consistent when using GTQs (90%) than without them (65%). Additionally, in the larger scale Job (where a single second of a video segment was overlapped by ratings of three sequentially neighboring segments), a mean unanimity of 94% was obtained with validated-as-correct ratings and 91% with non-validated ratings. Because the video segments overlapped in full for the small scale Job, and in part for the larger scale Job, it should be noted that such reliability reported here may not be directly comparable. Nonetheless, such results are both indicative of high levels of obtained rating reliability.
Overall, our results provide compelling evidence for CrowdFlower, via use of GTQs, being able to yield more accurate and consistent crowdsourced categorizations of naturalistic driving scene contents than when used without such a control mechanism. Such annotations in such short periods of time present a potentially powerful resource in driving research and driving automation development.
Background: Plasma leptin levels and plasma insulin levels have been found to be elevated in patients with essential hypertension (EH) and have been suggested to be components of the metabolic ...syndrome. Increased heart rate (HR) may predict the development of EH in normal or borderline-hypertensive individuals. The aim of our study was to test the hypothesis that elevated plasma leptin and insulin levels as well as systolic blood pressure (SBP) and diastolic blood pressure (DBP) and increased resting HR preexist in the healthy offspring of patients with EH. Methods and Results: Twenty-six (12 male, 14 female) healthy offspring of hypertensive patients, mean age 16 ± 2.5 years and body mass index (BMI) of 21.5 ± 2.8 kg/m2 (group A), and 30 (14 male, 16 female) healthy offspring of normotensive patients, mean age 17 ± 2.3 years and BMI of 21.9 ± 2.4 kg/m2 (group B), were studied. (The two groups were matched for sex, age, and BMI). Mean SBP, DBP, resting HR, plasma leptin, and plasma insulin levels (radioimmunoassay method) were determined in the whole study population. Mean SBP, DBP, and resting HR were significantly higher in group A than in group B (120 ± 12 vs 112 ± 9.5 mm Hg, 77 ± 9 vs 72 ± 7 mm Hg, 79 ± 8 vs 75 ± 5 beats/min, P < .01, P < .05, and P < .05, respectively). Plasma leptin and insulin levels were significantly higher in group A than in group B (9 ± 5.06 vs 5.6 ± 2.5 ng/mL and 20.11 ± 11.3 vs 14.8 ± 5.2 μIU/mL, P < .01 and P < .05, respectively). Conclusions: Our findings support the hypothesis that hyperleptinemia, hyperinsulinemia, and elevated blood pressure and resting HR preexist in the healthy offspring of patients with EH. (Am Heart J 1999;138:922-5.)
ACE-inhibitors prevent the development of left ventricular hypertrophy (LVH). The tumor suppressor gene p53 up-regulates the cellular renin-angiotensin system, resulting in ANG II synthesis, which ...activates p53 creating a positive feedback loop. One hundred and fourteen rabbits were separated into groups A (control), B (sham-operated), C and D. In groups C and D, an aortic stenosis was performed, and in group D the animals were treated with enalapril. For p53 determination, LV specimens were examined by Western blot analysis and an immunohistochemical study was performed, except for samples from group D. In conclusion, LVH was significantly induced at 7 and 28 days after aortic stenosis with no difference between the two periods, while enalapril prevented hypertrophy in these two groups. p53 was transcriptionally activated and immunoreactively present after acute pressure overload as well as in the sham-operated group. Enalapril decreased the p53 expression at 180 min, 7 and 28 days following aortic stenosis.
This study was designed to investigate both resistance to activated protein C (APC-R) and the factor FV Q506 mutation incidence in patients with a history of acute myocardial infarction (AMI) and ...patients with primary hypertension (PH), a high-risk group for arterial thrombosis. Eighty patients with a history of AMI (group A), 160 patients with a history of PH (group B), and 124 age-matched controls without arterial disease (group C) were studied. APC-R was determined using the Coatest APC Resistance Kit of Chromagenix, Sweden. The prevalence of the FV Q506 mutation was estimated by DNA analysis (Bertina method). The prevalence of the FV Q506 mutation was 20%, 13.75%, and 8% in groups A, B, and C, respectively (A
v C
P
= .0466). The prevalence of APC-R was 47.5% in group A
v 13% in group C (
P
< .0001) and 36.25% in group B
v 13% in group C (
P
< .0001). The response to activated protein C expressed as mean value
± SD was 2.05
± 0.33 in group A
v 2.56
± 0.46 in group C (
P
< .05) and 2
± 0.22 in group B
v 2.56
± 0.46 in group C (
P
< .05). These findings suggest that patients with a history of AMI or PH have a significantly increased incidence of both APC-R and FV Q506 mutation compared with the control group. These findings support the hypothesis that these anticoagulant defects may be risk factors for arterial thrombosis.
Background
Left atrial systolic dysfunction, unexplained by altered loading conditions, has been reported in idiopathic dilated cardiomyopathy suggesting left atrial involvement in the myopathic ...process.
Materials and methods
Seventeen patients with idiopathic dilated cardiomyopathy, 16 with ischemic dilated cardiomyopathy and 18 normal controls were studied with transthoracic echocardiography and cardiac catheterization. Transmitral diastolic flow was evaluated with pulsed Doppler. Left atrial volume (cm3/m2) at mitral valve opening (maximal, Vmax.), onset of atrial systole (P wave of the electrocardiogram, Vp), and mitral valve closure (minimal, Vmin.) was determined with two‐dimensional echocardiography using the biplane area‐length method. The left atrial active emptying fraction (ACTEF = Vp‐Vmin. × 100/Vp) served as an index of systolic function.
Results
The peak early diastolic transmitral flow velocity (cm/sec) was similar in the three groups (idiopathic: 60 ± 16, ischemic: 58 ± 20, control: 56 ± 22; P = NS), whereas the late diastolic transmitral flow velocity was lower but not significantly different in idiopathic compared to ischemic cardiomyopathy, and in both was lower than control (26 ± 12 vs. 34 ± 13 vs. 44 ± 14, respectively; P < 0.05). Vmax. and Vp were similar in idiopathic and ischemic cardiomyopathy and greater than control (44.6 ± 13.6 vs. 48.2 ± 18.3 vs. 26.9 ± 6.2; P < 0.05, and 34.6 ± 13.4 vs. 30.8 ± 10.9 vs. 16.7 ± 3.7, respectively; P < 0.05). ACTEF was lower in idiopathic than in ischemic cardiomyopathy and in the latter it was similar to control (18 ± 10% vs. 32 ± 10% vs. 36 ± 10%, respectively; P < 0.05). Moreover, ACTEF was inversely related to left atrial tension at end‐of atrial systole both in idiopathic and in ischemic cardiomyopathy (r2 = 0.52, P = 0.001 and r2 = 0.57, P = 0.0007, respectively). However, at any given level of left atrial tension at end of atrial systole, ACTEF was lower in idiopathic than ischemic cardiomyopathy.
Conclusion
Left atrial systolic function is depressed in idiopathic and preserved in ischemic dilated cardiomyopathy despite similar left atrial loading conditions. This finding suggests left atrial myopathy in the former, and may be related to the differences in the response to medical treatment and clinical outcome observed between the two conditions.
Human performance is a significant contributor to railway incidents and accidents. The literature shows that train drivers, signalers, and controllers most affect network safety. Several studies have ...been conducted in the field of human factors and human performance in the railway domain to investigate operators' influence on the railway system. However, most studies are based on previous studies from other domains, which are not well suited and can be difficult to apply reliably to railway-specific operations. In light of the current limitations, this paper proposes a new approach referred to as the human performance railway operational index (HuPeROI). HuPeROI aims not only to estimate the human error probability for railway operations but also to propose mitigation strategies to minimize phenomena such as operators' degraded performance. HuPeROI is based on a performance-shaping factors taxonomy designed for the rail industry, referred to as the railway performance-shaping factor (R-PSF) taxonomy. The R-PSF taxonomy was developed on the basis of an extensive literature review of the field of human factors and subsequently validated against the findings derived from the analysis of 179 railway accident and incident reports, as well as targeted interviews with subject matter experts. This paper presents the taxonomy and the underlying theory, as well as the results of the validation process based on the analysis of 179 reports and the assessment of R-PSFs for four different scenarios based on a subject matter expert elicitation process. The R-PSF taxonomy and HuPeROI should enable researchers to address and deal with the effect of degraded performance of railway operators.
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