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Biomedical subjects

K S Berbaum

Publications and source records attributed to K S Berbaum.

At least 73 records · Page 4Linked to original sources
PubMed1991

Visual tasks in helicopter shipboard landing.

The purpose of this research was to identify visual scene content important in helicopter shipboard landings, particularly in the hover phase, for further study in a research simulator. A second purpose was to illustrate the use of a methodology (Protocol Analysis) which may hold promise for many areas of human factors research. Discussions with pilots, reviews of relevant Naval Aviation Training and Operational Procedures (NATOPS) manuals and observation of simulated helicopter shipboard landings suggested that the visual elements required in helicopter shipboard landings may depend upon whether experienced or inexperienced pilots are flying, a simulator or an aircraft is flown, the environment is day or night, or the pilot seeks to acquire or maintain a skill level. A scenario involving an experienced pilot flying dusk/night approaches in a simulator was intensively studied. As he flew each approach, the pilot dictated real-time verbal protocols of his visual and control activities. These protocols were subsequently partitioned by the authors into nine phases defined in terms of range or altitude from the ship, and the visual tasks required in each segment were described. An outcome of this analysis was a list of visual cue augmentations that may be useful for providing augmented feedback in training.

Aircraft↗
PubMed1991

Hematoma formation after diagnostic angiography: effect of catheter size.

The authors studied the effect of catheter size on the development of hematomas after catheterization. Four hundred ninety-nine patients who underwent routine diagnostic angiography were randomized to receive either 5-F or 7-F catheters. Small hematomas were more frequent in the 7-F catheter group (P less than .05); however, there was no difference in the frequency of larger hematomas between groups. Compression time was slightly but significantly (P less than .001) longer in the 7-F group. When catheter size; duration of the procedure; and patient age, weight, blood pressure and coagulation status were considered as independent variables, patient weight was the most accurate predictor of hematoma formation. The authors conclude that catheter size does not affect the development of a clinically significant hematoma after diagnostic angiography and that other factors such as patient weight are more important in this regard.

Angiography↗
PubMed1991

Time course of satisfaction of search.

"Satisfaction of search" (SOS) refers to the effect in which a second lesion remains undetected after detection of another lesion on the same radiograph. The objective of this study was to clarify our understanding of SOS by relating it to total time of inspection and time intervals before, between, and after discovery of lesions. Detection accuracy of native lesions in chest radiographs, before and after the addition of a simulated nodular lesion, was measured for ten observers. Analysis of data from this and a previous experiment showed that average perceptual accuracy of individual receiver operating characteristic curves was significantly reduced with the addition of the nodules. Plots and analyses of search time revealed that, on average, during a typical 46-second inspection of a case, simulated nodules were found at 18 seconds, native abnormalities at 25 seconds, and false positives occurred at 33 seconds. Time needed to find nodules did not depend on whether native lesions were present; time to find native lesions did not change with addition of nodules; and total search time was the same for images with one, two, or no lesions. The detection results show that the SOS effect was obtained, but that interrupting search in order to measure it also diminishes accuracy. Analysis of the time course data relates SOS to perceptual capture and strategic halting of search.

Diagnostic Errors↗
PubMed1991

Two urokinase dose regimens in native arterial and graft occlusions: initial results of a prospective, randomized clinical trial.

The effects of two urokinase (UK) dose regimens on lysis time, lytic success, primary clinical success, and frequency of complications of peripheral thrombolysis were compared. Seventy-two intraarterial UK infusions were performed by means of standard catheter-directed infusion techniques in 63 patients with symptomatic peripheral arterial or bypass graft occlusions. Patients were prospectively randomized to high-dose (250,000 U/h for 4 hours and then 125,000 U/h) or low-dose (50,000 U/h) regimens. The mean time to complete lysis was 20.8, 26.0, 16.5, and 18.2 hours for the high-dose artery, low-dose artery, high-dose graft, and low-dose graft groups, respectively (P was not significant). Respective mean infusion durations were 27.1, 35.4, 22.2, and 25.3 hours. Clinical success was achieved in 65%-85% of cases. The frequency of complications was equivalent between groups, except for a higher frequency of minor bleeding complications in the high-dose group. The two urokinase dose regimens studied were equally effective in enabling peripheral thrombolysis.

Angiography↗
PubMed1991

Magnetic resonance imaging and computed tomography in pediatric head and neck masses.

Fifty-three magnetic resonance imaging (MRI) and 25 computed tomography (CT) studies of 53 head and neck masses in pediatric patients were reviewed retrospectively. All lesions had pathologic proof except for 2 metastatic and 2 recurrent lesions, which only had prior pathologic confirmation at their primary sites. These included 12 malignant tumors, 23 benign tumors, 6 inflammatory masses, and 12 congenital lesions. The MRI performance ranged predominantly from good to excellent in detection of the lesion and the extent of involvement and in contrast to the surrounding tissue; when CT comparison was available, MRI proved to be equal to or better than it in detection of these factors and in preoperative diagnosis. Our results suggest that MRI should be the method of choice for the initial evaluation of the pediatric head and neck region, especially in those patients requiring multiple examinations. However, CT and MRI should be used conjunctively in complicated cases, especially those possibly involving lesions with calcifications or bony involvement.

Adolescent↗
PubMed1991

Analysis of the cost-effectiveness of PACS.

Picture archiving and communications systems (PACS) have emerged as an important part of digital imaging technology. However, the future of PACS is uncertain because its economic viability is in doubt. Cost-effectiveness analysis is an accepted technique for evaluating the economics of new technologies. This paper addresses the cost-effectiveness of PACS and identifies factors that are important in determining the cost of PACS relative to film-based radiology. These include the impact of PACS on physician productivity, maintenance costs, discount rates, and the time period for amortization of capital goods. The effectiveness of PACS is also explored in terms of improvements in diagnostic accuracy and timely diagnosis. Financial and clinical impacts should be integrated to provide information about how PACS expenditures will affect radiology departments, hospitals, and national research and development objectives.

Cost-Benefit Analysis↗
PubMed1991

Randomized double-blind trial of midazolam/placebo and midazolam/fentanyl for sedation and analgesia in lower-extremity angiography.

Safety and efficacy of two drug regimens used for sedation and analgesia during lower-extremity angiography were studied. Midazolam (loading dose 14.5 micrograms/kg; maintenance dose, 7.2 micrograms/kg) with or without fentanyl (loading dose, 0.725 micrograms/kg; maintenance dose, 0.362 micrograms/kg) was administered in a blind fashion as an IV bolus to 50 patients. Hemodynamic responses were monitored, and a standardized questionnaire was given to the patient before, immediately after, and 8-24 hr after the procedure. Physicians also were asked questions after the procedure. Heart rate and oxygen saturation were not significantly different before and 2 min after administration or between groups. A small but significant decrease in blood pressure occurred 2 min after the loading dose was given in both groups. Both drug regimens had statistically significant anxiolytic effects; however, anxiolytic effects were superior in the midazolam/fentanyl group (p less than .02). Patients rated the overall effectiveness of anesthesia with midazolam/fentanyl as superior (p less than .02). Analysis of physicians' judgments of the effectiveness of sedation and analgesia showed a statistically significant advantage for the midazolam/fentanyl group (p less than .01). We conclude that midazolam/fentanyl appears to be as safe as and more efficacious than midazolam alone for sedation and analgesia during lower-extremity angiography.

Angiography↗
PubMed1990

Satisfaction of search in diagnostic radiology.

A subset of underreading errors (false-negative responses) in radiology has been attributed to "satisfaction of search," which occurs when lesions remain undetected after detection of an initial lesion. This phenomenon has not been studied in the experimental laboratory. A primary goal of this study was to develop a procedure or paradigm to study satisfaction of search. The authors measured detection accuracy for native lesions in images before and after the addition of a simulated nodular lesion. Simulated and native lesions were not spatially superimposed and the native abnormalities were physically identical with and without the nodules. Only responses related to the native lesion were analyzed. Accuracy parameters of receiver operating characteristic (ROC) curves were estimated by the method of maximum likelihood and jackknife. The average perceptual accuracy of the individual ROC curves as measured by Az and de' was significantly reduced with addition of the nodules (t = 2.364, p = 0.025, t = 2.648, p = 0.017, respectively). Az and de' parameters of the pooled ROC curve showed a similar effect (t = 1.573, p = 0.080; t = 1.934, p = 0.047, respectively). The results indicated a substantial satisfaction-of-search effect, with diminished accuracy in perception of native lesions.

Adolescent↗
PubMed1990

Plaque modification with tetracycline: enhanced tissue ablation with the excimer laser.

Tetracycline has been shown to collect selectively in atherosclerotic plaque and is a known photosensitizing agent. To determine if tetracycline enhances the photoablative effects of the ultraviolet xenon-fluorine excimer laser, the authors exposed four cadaveric aortic samples to tetracycline and four to only normal saline. Ninety-three sites in the samples were subjected to laser energy and analyzed with light microscopy for crater depth and width and for degree of thermal injury. Forty-three of the sites were histologically normal, and 50 were atherosclerotic. Crater depth did not differ significantly in atherosclerotic and normal sites not exposed to tetracycline. Atherosclerotic sites exposed to tetracycline showed significantly deeper craters compared with those in normal, exposed sites. The effects of tetracycline exposure and histologic characteristics (normal vs atherosclerotic) on crater width and thermal injury were independent and additive. When the excimer laser is used for treatment, tetracycline can definitely enhance atherosclerotic plaque ablation.

Aorta↗
PubMed1990

Techniques for lower-limb angiography: a comparative study.

Three separate variables--volume of contrast material, site of contrast material injection, and arterial inflow occlusion--were tested in a prospective, randomized fashion in 52 patients to determine the best technique for lower-limb angiography. Twelve patients received 30 and 60 mL of contrast material injected at the level of the external iliac artery (EIA), 20 patients received 60 mL injected at the level of the EIA with and without inflow occlusion, and 20 patients received 120 mL injected at the level of the aortic bifurcation and 60 mL injected at the level of the EIA. A total of 104 angiograms were obtained, two in each patient. Two examiners reviewed all angiograms in a blinded fashion, initially as 104 separate studies for diagnostic adequacy (ie, the need for additional angiography) and then as 52 paired studies for direct comparison of the quality of arterial filling (ie, the best-appearing angiogram). The 60-mL studies were significantly better (P less than .001) in both categories when compared with both the 30- and the 120-mL studies. There was, however, no significant difference between the 60-mL studies with and without inflow occlusion. The authors conclude that the best screen-film lower-limb angiograms are obtained with large volumes (60 mL) of contrast material injected below the pelvic vessels (EIA).

Adult↗
PubMed1990

Vection and simulator sickness.

Simulator sickness has been identified as a form of motion sickness in which users of simulators exhibit symptoms characteristic of true motion sickness. In a fixed-base simulator, visual and vestibular sources of information specifying dynamic orientation are in conflict to the extent that the optical flow pattern viewed by the pilot creates a compelling illusion of self-motion, which is not corroborated by the inertial forces transmitted through the vestibular sense organs. Visually induced illusory self-motion is known as vection, and a strict interpretation of sensory conflict theory of motion sickness suggests that vection in a fixed-base simulator would be a necessary precondition for simulator sickness. Direct confirmation of this relation is reported in this article.

Adolescent↗
PubMed1989

Political trends in vascular and interventional radiology: a randomized survey.

There is a trend in the United States toward the performance of vascular and interventional radiology procedures by nonradiologists. A survey was conducted of 2.069 U.S. radiologists to define better the current status of and gather opinions on the future of vascular and interventional radiology. A total of 715 (35%) completed questionnaires were returned. Cross tabulations among subgroups of respondents were performed to address key issues. The median proportion of time spent in the performance of vascular and interventional radiology was 10%, and 51.5% of the radiologists surveyed were in groups that included a fellowship-trained interventional radiologist. More than half (54.4%) of the radiologists indicated that nonradiologists have expressed interest in performing vascular and interventional techniques. According to 13.4% of the radiologists surveyed, cardiologists performed at least some peripheral angiography or angioplasty. The vast majority of radiologists (96.8%) did not want other specialties to assume vascular and interventional radiology procedures, but 16.8% believed these procedures will eventually be lost to other specialties. The results indicate that vascular and interventional radiology is being infringed on to a relatively large degree by other specialties.

Attitude of Health Personnel↗