  Augmented Reality (AR) systems describe the class of systems that use
computers to overlay virtual information on the real world. AR environments
allow the development of promising tools in several application domains. In
medical training and simulation the learning potential of AR is significantly
amplified by the capability of the system to present 3D medical models in
real-time at remote locations. Furthermore the simulation applicability is
broadened by the use of real-time deformable medical models. This work presents
a distributed medical training prototype designed to train medical
practitioners' hand-eye coordination when performing endotracheal intubations.
The system we present accomplishes this task with the help of AR paradigms. An
extension of this prototype to medical simulations by employing deformable
medical models is possible. The shared state maintenance of the collaborative
AR environment is assured through a novel adaptive synchronization algorithm
(ASA) that increases the sense of presence among participants and facilitates
their interactivity in spite of infrastructure delays. The system will allow
paramedics, pre-hospital personnel, and students to practice their skills
without touching a real patient and will provide them with the visual feedback
they could not otherwise obtain. Such a distributed AR training tool has the
potential to: allow an instructor to simultaneously train local and remotely
located students and, allow students to actually "see" the internal anatomy and
therefore better understand their actions on a human patient simulator (HPS).
