While telemedicine is now well established in many areas of medical practice, it is only beginning to create impact in some of the more complex medical applications such as critical care. New systems based on advanced technologies such as the Virtual Critical Care Unit and the eICU have recently successfully demonstrated the provision of critical care services from a distance in emergency and intensive care respectively. These specialties make particular demands on a telemedicine system, and studies in computer supported collaborative work as well as studies of work practices suggest that there is a minimum threshold of technology complexity for supporting such applications. The eICU relies mainly on transmitting a rich data space to a remotely located specialist, while ViCCU^® relies on creating a sense of presence. Other systems rely on complex physiological models. These approaches exemplify two trends in telemedicine systems of the future, with enhanced immersiveness creating a high sense of presence, and ready access to structured patient-specific data providing assistance to decision support. The future of telemedicine technology may see a convergence of these two trends.