Biomedical subjects

Alan Liu

Publications and source records attributed to Alan Liu.

5 recordsLinked to original sources

PubMed2006

Bounds for damping that guarantee stability in mass-spring systems.

Mass-spring systems are often used to model anatomical structures in medical simulation. They can produce plausible deformations in soft tissue, and are computationally efficient. Determining damping values for a stable mass-spring system can be difficult. Previously stable models can become unstable with topology changes, such as during cutting. In this paper, we derive bounds for the damping coefficient in a mass-spring system. Our formulation can be used to evaluate the stability for user specified damping values, or to compute values that are unconditionally stable.

Algorithms↗

PubMed2006

The design and implementation of a pulmonary artery catheterization simulator.

Pulmonary Artery Catheterization (PAC) is a commonly performed procedure. It is used when hemodynamic and other cardiac measures must be accurately monitored in seriously ill patients. A flow-directed, balloon-tipped (Swan-Ganz) catheter is typically inserted into a major vein, passed through the heart, and into the pulmonary artery. This procedure is normally not performed under fluoroscopy. Instead, transducer readings from the catheter tip provide a continuous report of local blood pressure. An experienced practitioner can infer the catheter's location from this information, yet several studies have found that physicians and critical care nurses have a wide variability in competency. A simulator for this procedure can address some of the educational and training issues highlighted. This paper describes our ongoing progress in developing a PAC trainer.

Catheterization↗

PubMed2005

Simulating surgical incisions without polygon subdivision.

Modeling cuts, bleeding and the insertion of surgical instruments are essential in surgical simulation. Both visual and haptic cues are important. Current methods to simulate cuts change the topology of the model, invalidating pre-processing schemes or increasing the model's complexity. Bleeding is frequently modeled by particle systems or computational fluid dynamics. Both can be computationally expensive. Surgical instrument insertion, such as intubation, can require complex haptic models. In this paper, we describe methods for simulating surgical incisions that do not require such computational complexity, yet preserve the visual and tactile appearance necessary for realistic simulation.

Blood Loss, Surgical↗

PubMed2005

A haptic-enabled simulator for cricothyroidotomy.

Cricothyroidotomy is an emergency procedure that is performed when the patient's airway is blocked, and less invasive attempts to clear it have failed. Cricothyroidotomy has been identified as an essential skill for military readiness. This training is relevant to more than 40,000 U.S. military medics, and thousands of civilian health care providers. Current training methods use animals, cadavers and plastic mannequins. Animal models do not have the correct anatomy. Cadavers do not have the correct physiology. Mannequins do not adequately cover the full range of anatomical variations. In this paper, we describe our effort to build a computer-based cricothyroidotomy simulator to address these problems.

Computer Simulation↗

PubMed2005

Homeland security and virtual reality: building a Strategic Adaptive Response System (STARS).

The advent of the Global War on Terrorism (GWOT) underscored the need to improve the U.S. disaster response paradigm. Existing systems involve numerous agencies spread across disparate functional and geographic jurisdictions. The current architecture remains vulnerable to sophisticated terrorist strikes. To address these vulnerabilities, we must continuously adapt and improve our Homeland Security architecture. Virtual Reality (VR) technologies will help model those changes and integrate technologies. This paper provides a broad overview of the strategic threats, together with a detailed examination of how specific VR technologies could be used to ensure successful disaster responses.

Disaster Planning↗