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result(s) for
"Hamilton, Allan J"
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A computerized assessment to compare the impact of standard, stereoscopic, and high-definition laparoscopic monitor displays on surgical technique
2010
Background
Surgeons performing laparoscopic surgery have strong biases regarding the quality and nature of the laparoscopic video monitor display. In a comparative study, we used a unique computerized sensing and analysis system to evaluate the various types of monitors employed in laparoscopic surgery.
Methods
We compared the impact of different types of monitor displays on an individual’s performance of a laparoscopic training task which required the subject to move the instrument to a set of targets. Participants (varying from no laparoscopic experience to board-certified surgeons) were asked to perform the assigned task while using all three display systems, which were randomly assigned: a conventional laparoscopic monitor system (2D), a high-definition monitor system (HD), and a stereoscopic display (3D). The effects of monitor system on various performance parameters (total time consumed to finish the task, average speed, and movement economy) were analyzed by computer. Each of the subjects filled out a subjective questionnaire at the end of their training session.
Results
A total of 27 participants completed our study. Performance with the HD monitor was significantly slower than with either the 3D or 2D monitor (
p
< 0.0001). Movement economy with the HD monitor was significantly reduced compared with the 3D (
p
< 0.0004) or 2D (
p
< 0.0001) monitor. In terms of average time required to complete the task, performance with the 3D monitor was significantly faster than with the HD (
p
< 0.0001) or 2D (
p
< 0.0086) monitor. However, the HD system was the overwhelming favorite according to subjective evaluation.
Conclusion
Computerized sensing and analysis is capable of quantitatively assessing the seemingly minor effect of monitor display on surgical training performance. The study demonstrates that, while users expressed a decided preference for HD systems, actual quantitative analysis indicates that HD monitors offer no statistically significant advantage and may even worsen performance compared with standard 2D or 3D laparoscopic monitors.
Journal Article
A novel and inexpensive ballistic gel phantom for ultrasound training
by
Richard Amini Jeffrey Z Kartchner Lori A Stolz David Biffar Allan J Hamilton Srikar Adhikari
in
Continuing Education
,
Emergency medical care
,
Plumbing
2015
BACKGROUND: Ultrasonography use is increasing in emergency departments, and ultrasound education is now recommended in resident training. Ultrasound phantoms are used in many institutions for training purposes. The purpose of this study is to describe an inexpensive and simple method to create ultrasound-imaging models for the purpose of education and practice using clear ballistic gel.METHODS: Clear ballistic gel is used to simulate tissue for firing practice and other military evaluations.RESULTS: The transparent and durable ultrasound phantom we produced was clear and contained four vessel lumens. The images obtained using the phantom were of high quality and compared well to normal sonographic anatomy.CONCLUSIONS: The clear ballistic brand gel is unique because it is inexpensive, does not dry out, does not decay, is odorless, and is reusable. The ultrasound images obtained using the phantom are realistic and useful for ultrasound education.
Journal Article
Comparison of six display modes for a multi-resolution foveated laparoscope
2019
BackgroundTo overcome the field of view and ergonomic limitations of standard laparoscopes, we are developing a multi-resolution foveated laparoscope that can simultaneously obtain both wide- and zoomed-in-view images through a single scope. To facilitate the effective access to the dual views of images with different resolution and field coverage acquired by our laparoscope, six different display modes have been developed. Each of the six display modes has inherent advantages and disadvantages. This study compares the six display modes through a human-subject experiment, which was conducted with an emulated laparoscope using a 4K camera.MethodsTwenty-four subjects without medicine background performed three evaluation trials of a touching task with each of the display modes. Various objective measurements including task completion time, the number of collisions, gaze position, and tooltip position, and subjective preference for the display modes were recorded.ResultsFor all the measurements except for task completion time and moving speed of tooltip, there were statistically significant differences among the display modes. Although the focus plus warped context view mode was selected as one of the least preferred modes, it showed the best task performance.ConclusionsThe unblocked wide context view was useful to provide a situational awareness even when it was severely distorted in some of the display modes, and information continuity played an important role in improving task performance. Moreover, the position change of viewing window coupled to the location of region of interest helped improve task performance, by providing an additional cue for spatial awareness.
Journal Article
The impact of implementation of a hysterectomy enhanced recovery pathway on anesthetic medication costs
2020
To evaluate the effect of implementation of a hysterectomy Enhanced Recovery After Surgery (ERAS) protocol on perioperative anesthetic medication costs.
Historical cohort study of 84 adult patients who underwent a hysterectomy. Forty-two patients who underwent surgery before protocol implementation comprised the pre-ERAS group. Forty-two patients who underwent surgery after protocol implementation comprised the post-ERAS group. Data on anesthetic medication costs and outcomes were analyzed.
Compared with the pre-ERAS group, the post-ERAS group’s total medication cost was significantly lower (median: 325.20 USD; interquartile range [IQR]: 256.12–430.65 USD vs median: 273.10 USD; IQR: 220.63–370.59 USD, median difference: -40.76, 95% CI: -130.39, 16.99, p = 0.047). Length of stay was significantly longer in pre-ERAS when compared with post-ERAS groups (median: 5.0 days; IQR: 4.0–7.0 days vs median: 3.0 days; IQR: 3.0–4.0 days, median difference: -2.0 days, 95% CI: -2.5581, -1.4419, p < 0.0001).
ERAS protocols may reduce perioperative medication costs.
Journal Article
Simulation-based surgical training systems in laparoscopic surgery: a current review
2021
Simulation-based training has been widely used in medical education. More specifically, various systems for minimally invasive surgery training have been proposed in the past two decades. The aim of this article is to review and summarize the existing simulation-based training systems for laparoscopic surgery in terms of their technical realizations. Forty-three training systems were found and analyzed. These training systems generally consist of training tasks, a visualization interface, and an instrument interface. Three different approaches—physical, virtual, and augmented reality—to implement visualization interfaces are discussed first. Then, haptic feedback, performance evaluation, and guidance methods are summarized. Portable devices to enable at-home training and instrument tracking technologies to support visualization, evaluation, and guidance are also presented. Based on survey of the relevant literature, we propose several recommendations to design the next-generation training systems in laparoscopic surgery. Novel guidance and assessment schemes with augmented reality visualization are recommended to design an intelligent surgical training simulator. This intelligent simulator enhances the training procedure and ultimately improves the patient safety.
Journal Article
Who shall live and who shall die
1984
The bizarre life and recent death of David, the boy in the bubble, have left me strangely upset. I am a physician and a researcher, and David's story seems to pose serious and fundamental questions about human existence in general and its relation to the medical community.
Magazine Article
Detailed budget analysis of HONO in central London reveals a missing daytime source
2016
Measurements of HONO were carried out at an urban background site near central London as part of the Clean air for London (ClearfLo) project in summer 2012. Data were collected from 22 July to 18 August 2014, with peak values of up to 1.8 ppbV at night and non-zero values of between 0.2 and 0.6 ppbV seen during the day. A wide range of other gas phase, aerosol, radiation, and meteorological measurements were made concurrently at the same site, allowing a detailed analysis of the chemistry to be carried out. The peak HONO/NOx ratio of 0.04 is seen at ∼ 02:00 UTC, with the presence of a second, daytime, peak in HONO/NOx of similar magnitude to the night-time peak, suggesting a significant secondary daytime HONO source. A photostationary state calculation of HONO involving formation from the reaction of OH and NO and loss from photolysis, reaction with OH, and dry deposition shows a significant underestimation during the day, with calculated values being close to 0, compared to the measurement average of 0.4 ppbV at midday. The addition of further HONO sources from the literature, including dark conversion of NO2 on surfaces, direct emission, photolysis of ortho-substituted nitrophenols, the postulated formation from the reaction of HO2 × H2O with NO2, photolysis of adsorbed HNO3 on ground and aerosols, and HONO produced by photosensitized conversion of NO2 on the surface increases the daytime modelled HONO to 0.1 ppbV, still leaving a significant missing daytime source. The missing HONO is plotted against a series of parameters including NO2 and OH reactivity (used as a proxy for organic material), with little correlation seen. Much better correlation is observed with the product of these species with j(NO2), in particular NO2 and the product of NO2 with OH reactivity. This suggests the missing HONO source is in some way related to NO2 and also requires sunlight. Increasing the photosensitized surface conversion rate of NO2 by a factor of 10 to a mean daytime first-order loss of ∼ 6 × 10−5 s−1 (but which varies as a function of j(NO2)) closes the daytime HONO budget at all times (apart from the late afternoon), suggesting that urban surfaces may enhance this photosensitized source. The effect of the missing HONO to OH radical production is also investigated and it is shown that the model needs to be constrained to measured HONO in order to accurately reproduce the OH radical measurements.
Journal Article