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PubMed1978

[Pathological observations on patients carrying pacemakers and clinical consequences. Reports of 105 observed cases (author's transl)].

In subjects carrying pacemakers, the catheter-electrode can induce, over a period of time, specific modifications at the level of the veins and the heart. The organism reacts to extraneous bodies with adhesive and sometimes thrombotic phenomena. The latter can occasionally be the cause of a pulmonary embolism (8 cases out of 105) or more rarely, the seat of a mycotic infection (one case). In the casuistry are included two cases of the complete perforation of the right ventricle (one of which was fatal) and four cases of partial perforation; in another subject a papillary muscle was perforated. Finally, one case of endocarditis was noted, the so called traumatic type, of the tricuspid valve.

Cardiovascular System↗
PubMed1993

[The risk assessment for a fatal outcome in patients with stable angina based on the data from a long-term prospective observation (a comparison of the 5-year survival prognosis with the data at the 6th to 12th years of the observation)].

A rule has been developed to predict coronary death in 377 patients with coronary heart disease and stable angina due to coronary stenotic atherosclerosis. Gravimetric values of various clinical signs, resting ECG changes, and bicycle ergometric testing have been obtained by a computer. A decisive rule has been also derived. According to the values of prognostic indices I1 and I2, groups of low, moderate, and high risks for fatal outcomes for 5 years have been identified and the patient's survival during a subsequent follow-up of 6 to 12 years has been assessed. The developed scheme of prognosis permits its use in practice.

Adult↗
PubMed1998

Studies in acute iron poisoning. I. Desferrioxamine In the treatment of acute iron poisoning: clinical observations, experimental studies, and theoretical considerations, by Charles F. Whitten et al, Pediatrics, 1965;36:322-335; and Studies in acute iron poisoning. II. Further observations on desferrioxamine in the treatment of acute experimental iron poisoning, by Charles F. Whitten et al, Pediatrics, 1966;38:102-110.

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Acute Disease↗
PubMed2004

The patient and observer scar assessment scale: a reliable and feasible tool for scar evaluation.

At present, various scar assessment scales are available, but not one has been shown to be reliable, consistent, feasible, and valid at the same time. Furthermore, the existing scar assessment scales appear to attach little weight to the opinion of the patient. The newly developed Patient and Observer Scar Assessment Scale consists of two numeric scales: the Patient Scar Assessment Scale (patient scale) and the Observer Scar Assessment Scale (observer scale). The patient and observer scales have to be completed by the patient and the observer, respectively. The patient scale's consistency and the observer scale's consistency, reliability, and feasibility were tested. For the Vancouver Scar Scale, which is the most frequently used scar assessment scale at present, the same statistical measurements were examined and the results of the observer scale and the Vancouver scale were compared. The concurrent validity of the observer scale was tested with a correlation to the Vancouver scale. Furthermore, the authors examined which specific characteristics significantly influence the general opinion of the patient and the observers on the scar areas. Four independent observers have each used the observer scale and the Vancouver scale to assess 49 burn scar areas of 3 x 3 cm belonging to 20 different patients. Subsequently, the patients completed the patient scale for their scar areas. The (internal) consistency of both the patient and the observer scales was acceptable (Cronbach's alpha, 0.76 and 0.69, respectively), whereas the consistency of the Vancouver scale appeared not to be acceptable (alpha, 0.49). The reliability of the observer scale completed by a single observer was acceptable (r = 0.73). The reliability of the Vancouver scale completed by a single observer was lower (r = 0.69). The observer scale showed better agreement than the Vancouver scale because the coefficient of variation was lower (18 percent and 22 percent, respectively). The concurrent validity of the observer scale in relation to the Vancouver scale is high (r = 0.89, p < 0.001). Linear regression of the general opinions on scars of the observer and the patient showed that the observer's opinion is influenced by vascularization, thickness, pigmentation, and relief, whereas the patient's opinion is mainly influenced by itching and the thickness of the scar. Such an impact of itching and thickness of the scar on the patient's opinion is an important and novel finding. The Patient and Observer Scar Assessment Scale offers a suitable, reliable, and complete scar evaluation tool.

Adolescent↗
PubMed1999

Inter-rater reliability of postural observation after stroke.

OBJECTIVE: To explore the inter-observer reliability of bedside observations of stroke patients' posture using two versions of a pictorial tool. DESIGN: Three projects were conducted. The initial version of the tool was used in project 1. The modified version was used in projects 2 and 3. In each project a pair of observers (comprising the main observer and one of five co-observers with varying degrees of experience in observing posture) used the tool to make simultaneous observations of 19 aspects of the posture of a sample of stroke patients. Each patient was observed in one or more of four positions (seated, supine and lying on the affected and unaffected side). The degree of inter-observer agreement was sought by calculating kappa values and percentage agreement. SETTING: Medical wards, care of the elderly wards and a stroke unit. SUBJECTS: A convenience sample of 57 stroke patients. RESULTS: Four hundred and forty paired sets of observations were made (200 in project 1, 140 in project 2 and 100 in project 3). The main observer was in every pair. The co-observers made between 50 and 135 sets of observations each. When the results from all three projects were amassed, acceptable percentage agreement (i.e. > or =70%) was obtained for 67% (n = 78) and 73% (n = 55) of the results collected on aspects of the posture of the affected upper and lower limbs respectively. In contrast, acceptable percentage agreement for observations relating to the head, neck and trunk was obtained for only 34% (n = 50) of the results collected. Uneven distributions in the data made kappa values difficult to interpret. Inter-observer agreement was not noticeably higher for pairs in which both observers had prior experience of observing posture after stroke than for pairs in which one observer was relatively inexperienced. CONCLUSIONS: The tool has potential as a quick and simple means of collecting information at the bedside about stroke patients' posture. Refinements, additional training in using the tool for observers and further testing are suggested before its wider use is advocated.

Adult↗
PubMed2004

[Connectionist models of social learning: a case of learning by observing a simple task].

This article proposes a connectionist model of the social learning theory developed by Bandura (1977). The theory posits that an individual in an interactive situation is capable of learning new behaviours merely by observing them in others. Such learning is acquired through an initial phase in which the individual memorizes what he has observed (observation phase), followed by a second phase where he puts the recorded observations to use as a guide for adjusting his own behaviour (reproduction phase). We shall refer to the two above-mentioned phases to demonstrate that it is conceivable to simulate learning by observation otherwise than through the recording of perceived information using symbolic representation. To this end we shall rely on the formalism of ecological neuron networks (Parisi, Cecconi, & Nolfi, 1990) to implement an agent provided with the major processes identified as essential to learning through observation. The connectionist model so designed shall implement an agent capable of recording perceptive information and producing motor behaviours. The learning situation we selected associates an agent demonstrating goal-achievement behaviour and an observer agent learning the same behaviour by observation. Throughout the acquisition phase, the demonstrator supervises the observer's learning process based on association between spatial information (input) and behavioural information (output). Representation thus constructed then serves as an adjustment guide during the production phase, involving production by the observer of a sequence of actions which he compares to the representation stored in distributed form as constructed through observation. An initial simulation validates model architecture by confirming the requirement for both phases identified in the literature (Bandura, 1977) to simulate learning through observation. The representation constructed over the observation phase evidences acquisition of observed behaviours, although this phase alone is not sufficient to ensure accurate reproduction and must be made functional through the production phase (Deakin & Proteau, 2000). Results obtained through a second simulation replicate those produced by Bandura & Jeffery (1973), who observed that the individual tested following the retention phase recalled recorded information better than he realized in the production phase. The outcome of a third simulation shows that, when performing the transfer task, agents performed the task all the more effectively when they were required to learn a simple path which facilitated knowledge transfer to an adjacent situation. New explanatory assumptions of the mechanics of learning through observation may be produced through OLEANNet. Thus, observed deterioration between memorization and production is caused by successive approximations which occur in the acquisition phase then in the production phase. Further, depending on the type of learning undergone by agents, use of representation as a production guide induces a more or less stringent constraint in the approximation of actual behaviour. This results, during the transfer task, in the ability to effectively generalize acquired knowledge where such knowledge is not specifically related to the task at hand. In conclusion, connectionist model architecture appears valid for modeling learning through observation as defined by Bandura (1977). However, certain limitations appear during implementation, especially in terms of the observed behaviour's availability and the planning of produced behaviours that future developments are liable to counter.

Humans↗
PubMed1995

Observation of emergency medicine residents at the bedside: how often does it happen?

OBJECTIVE: To determine how often trainees in emergency medicine (EM) are observed while performing a history, a physical examination, or specific procedures. METHODS: The 26 members of the National Consensus Group on Clinical Skills in Emergency Medicine affiliated with an EM residency program were asked to circulate a survey to their residents during February and March 1994. Twenty-one programs participated, surveying a total of 514 residents. The residents were asked how many times they had been observed by an attending physician while they performed a history, a physical examination, endotracheal intubation, or central vein catheterization during training. The residents also were asked about observation of specific components of the physical examination, such as the heart, lung, and genitourinary systems. RESULTS: Three hundred nineteen residents (62%) responded to the survey. Thirteen percent of the residents reported that they had never been observed taking a history during training. During their PGY1 training, 19% of the residents reported that they had never been observed taking a history, 42% had been observed one to three times, 25% had been observed four to 12 times, and 13% had been observed > 12 times. Six percent of the residents reported that they had never been observed doing a physical examination during training. During their PGY1 training, 10% of the residents had never been observed performing a physical examination, 38% had been observed one to three times, 34% had been observed four to 12 times, and 18% had been observed > 12 times. CONCLUSIONS: Many residents report that they are infrequently observed performing histories and physical examinations during their EM training, with a significant number of residents reporting that they were never observed performing basic bedside clinical skills. More direct observation with trained faculty observers may provide an opportunity for better evaluation and remediation of bedside clinical skills.

Adult↗
PubMed1999

Observer variability in interpretation of abdominal radiographs of infants with suspected necrotizing enterocolitis.

We examined (1) the observer variability (both interobserver and intraobserver) in interpretation of abdominal radiographs of infants with suspected necrotizing enterocolitis (NEC), (2) the interobserver variability for individual radiologic signs used to diagnose NEC, and (3) the influence of experience in determining the extent of observer variability. Our hypotheses were (1) there would be considerable observer variability in interpretation of abdominal radiographs of infants with suspected NEC; (2) the extent of observer variability would differ for individual radiologic signs of NEC; and (3) the extent of observer variability would be determined by the observer's experience. The participants included 12 observers: two pediatric radiologists, four attending neonatologists, three neonatal fellows, and three pediatric residents. The participating observers under similar interpretation conditions, twice independently, interpreted the same 40 pairs of abdominal radiographs from infants with suspected NEC. The interval between the two interpretations was 3 to 6 months. Intraobserver and interobserver variability was assessed by applying the Kappa statistic to the radiologic signs of NEC for the two separate interpretations. The observers were blinded to patient's identity and the clinical course. Each observer recorded the absence, suspicion, or presence of (1) intestinal distention, (2) air fluid levels, (3) bowel wall thickening, (4) pneumatosis intestinalis, (5) portal venous gas, (6) pneumoperitoneum, and (7) NEC. We found low intraobserver and interobserver agreements. There was considerable variation in observer variability for individual radiologic signs. Trained observers performed better than intraining observers. We conclude that the radiologic signs in isolation should not be considered reliable. We recommend studies to formulate more objective criteria for many of the radiographic features of NEC. Standardization and periodic enforcement of these criteria among observers could reduce observer variability. We suggest that, to decrease both false-negative and false-positive interpretation, an experienced observer should always review the radiographs of infants with suspected NEC.

Diagnosis, Differential↗
PubMed1986

Nurses' response to doctors' orders for close observation.

Informal observation seemed to show that doctors' orders for close observation were treated in a manner different from other orders for patient care. A subsequent formal study involved 26 nurses over a four-month period. Data was collected by direct observation and through brief interviews with the nurses. A shift or part-shift involving a nurse and his patient on close observation was defined as the observation unit. Only 23% of the 284 observation units complied approximately with hospital policies for close observation. Forty-one percent of the observation units were recorded as totally non-compliant. No observation unit fulfilled the policy requirements in the strictest sense. Nurses provided close observation for almost as many patients on general observation as they gave general observation to those for whom close observation had been ordered. These data suggest that in most cases nurses use something other than doctors' orders to determine the observation needs of their patients. The author suggests that doctors' orders for close and general observation be abandoned and that only orders for constant observation be retained, in conformity with what is already going on.

Alberta↗
PubMed2005

Task-based model/human observer evaluation of SPIHT wavelet compression with human visual system-based quantization.

RATIONALE AND OBJECTIVE: The set partitioning in hierarchical trees (SPIHT) wavelet image compression algorithm with the human visual system (HVS) quantization matrix was investigated using x-ray coronary angiograms. We tested whether the HVS quantization matrix for the SPIHT wavelet compression improved computer model/human observer performance in a detection task with variable signals compared to performance with the default quantization matrix. We also tested the hypothesis of whether evaluating the rank order of the two quantization matrices (HVS versus default) based on performance of computer model observers in a signal known exactly but variable task (SKEV) generalized to model/human performance in the more clinically realistic signal known statistically task (SKS). MATERIALS AND METHODS: Nine hundred test images were created using real x-ray coronary angiograms as backgrounds and simulated arteries with filling defects (signals). The task for the model and human observer was to detect which one of the four computer simulated arterial segments contained the signal, four alternative-forced-choice (4 AFC). We obtained performance for four model observers (nonprewhitening matched filter with an eye filter, Hotelling, Channelized Hotelling, and Laguerre Gauss Hotelling model observers) for both the SKEV and SKS tasks with images compressed with and without the HVS quantization matrix. A psychophysical study measured performance from three human observers for the same conditions and tasks as the model observers. RESULTS: Performance for all four model observers improved with the use of the HVS quantization scheme. Improvements ranged from 5% (at compression ratio 7:1) to 50% (at compression ratio 30:1) for both the SKEV and SKS tasks. Human observer performance improvement averaged across observers ranged from 6% (at compression ratio 7:1) to 35% (at compression ratio 30:1) for the SKEV task and from 2% (at compression ratio 7:1) to 38% (at compression ratio 30:1) for the SKS task. Addition of internal noise to the model observers allowed for good prediction of human performance. CONCLUSIONS: Use of the HVS quantization scheme in the SPIHT wavelet compression led to improved model and human observer performance in clinically relevant detection tasks in x-ray coronary angiograms. Model observer performance can be reliably used to predict the human observer performance for the studied tasks as a function of SPIHT wavelet image compression. Our results further confirmed that model observer performance in the computationally more tractable SKEV task can be potentially used as a figure of merit for the more clinically realistic SKS task with real anatomic backgrounds.

Algorithms↗
PubMed2006

In-hospital observation after antibiotic switch in pneumonia: a national evaluation.

PURPOSE: To evaluate the clinical benefit of in-hospital observation after the switch from intravenous (IV) to oral antibiotics in a large Medicare population. Retrospective studies of relatively small size indicate that the practice of in-hospital observation after the switch from IV to oral antibiotics for patients hospitalized with community-acquired pneumonia (CAP) is unnecessary. METHODS: We performed a retrospective examination of the US Medicare National Pneumonia Project database. Eligible patients were discharged with an ICD-9-CM diagnosis consistent with community-acquired pneumonia and divided into 2 groups: 1) a "not observed" cohort, in which patients were discharged on the same day as the switch from IV to oral antibiotics and 2) an "observed for 1 day" cohort, in which patients remained hospitalized for 1 day after the switch from IV to oral antibiotics. We compared clinical outcomes between these 2 cohorts. RESULTS: A total of 39,242 cases were sampled, representing 4341 hospitals in all 50 states and the District of Columbia. There were 5248 elderly patients who fulfilled eligibility criteria involving a length of stay of no more than 7 hospital days (2536 "not observed" and 2712 "observed for 1 day" patients). Mean length of stay was 3.8 days for the "not observed" cohort and 4.5 days for the "observed for 1 day" cohort (P <.0001). There was no significant difference in 14-day hospital readmission rate (7.8% in the "not observed" cohort vs 7.2% "observed for 1 day" cohort, odds ratio 0.91; 95% confidence interval [CI] 0.74-1.12; P =.367) and 30-day mortality rate (5.1% "not observed" cohort vs 4.4% in the "observed for 1 day" cohort, odds ratio 0.86; 95% CI, 0.67-1.11; P =.258) between the "not observed" and "observed for 1 day" cohorts. CONCLUSIONS: Our analysis of the US Medicare Pneumonia Project database provides further evidence that the routine practice of in-hospital observation after the switch from IV to oral antibiotics for patients with CAP may be avoided in patients who are clinically stable although these findings should be verified in a large randomized controlled trial.

Administration, Oral↗
PubMed2004

Observer variability when evaluating patient movement from electronic portal images of pelvic radiotherapy fields.

BACKGROUND AND PURPOSE: A study has been performed to evaluate inter-observer variability when assessing pelvic patient movement using an electronic portal imaging device (EPID). MATERIALS AND METHODS: Four patient image sets were used with 3-6 portal images per set. The observer group consisted of nine radiographers with 3-18 months clinical EPID experience. The observers outlined bony landmarks on a digital simulator image and used matching software to evaluate field placement errors (FPEs) on each portal image relative to the reference simulator image. Data were evaluated statistically, using a two-component analysis of variance technique, to quantify both the inter-observer variability in evaluating FPEs and inter-fraction variability in patient position relative to the residuals of the analysis. Intra-observer variability was also estimated using four of the observers carrying out three sets of repeat readings. RESULTS: Eight sets of variance data were analysed, based on FPEs in two orthogonal directions for each of the four patient image sets studied. Initial analysis showed that both inter-observer variation and inter-fraction-patient position variation were statistically significant (P<0.05) in seven of the eight cases evaluated. The averaged root-mean-square (RMS) deviation of the observers from the group mean was 1.1 mm, with a maximum deviation of 5.0 mm recorded for an individual observer. After additional training and re-testing of two of the observers who recorded the largest deviations from the group mean, a subsequent analysis showed the inter-observer variability for the group to be significant in only three of the eight cases, with averaged RMS deviation reduced to 0.5 mm, with a maximum deviation of 2.7 mm. The intra-observer variability was 0.5 mm, averaged over the four observers tested. CONCLUSIONS: We have developed a quantitative approach to evaluate inter-observer variability in terms of its statistical significance compared to inter-fraction patient movement. This will assist us in training and assessing observers required to perform this task on a routine basis.

Electronics↗