Technology and Health Care

Teleradiology, the electronic transmission of radiological images for the purposes of interpretation and consultation, has successfully entered routine health services. It is, therefore, currently one of the single largest applications of telemedicine. This technology is predicted to play a significant role in improving service access to rural and remote areas. However, teleradiology services are currently characterized by a compromise between expense and quality of digital images. This paper reviews minimum equipment requirements and the technical issues and limits that are experienced when utilizing current teleradiological technology. Categories of service evaluation, including measures of user satisfaction, clinical outcome and financial benefit, are discussed in relation to facilitating a radiology service of the highest quality possible.

Monitoring the status of preterm infants in the Neonatal Intensive Care Unit (NICU) provides a unique and challenging environment for the design, function and use of sensor-based monitoring equipment. This article presents an overview of sensor-based instrumentation used in the NICU for physiological and chemical status monitoring, and discusses some of the key sensing principles currently in use. The clinical demand for reliable patient data at acceptable cost is driving the development of new types of monitoring technologies, in particular for continuous blood-chemistry analysis. We describe some of the new sensor-based products finding their way into the NICU, together with a review of the more promising emerging sensor technologies that might eventually be incorporated into routine neonatal monitoring practice.

During mechanical ventilation, the resistance of the endotracheal and tracheostomy tube (ETT) highly influences analysis of respiratory system mechanics and imposes additional work of breathing for the spontaneously breathing patient which both can be circumvented by applying the automatic tube compensation (ATC) mode. In the ATC mode, tracheal pressure (p_trach) is continuously calculated on the basis of measured flow and airway pressure using predetermined tube specific coefficients. However, as during long-term ventilation the ETT might become partially obstructed by secretions or tube kinking, the predetermined coefficients are no longer valid rendering calculation of p_trach inaccurate. We propose an easy-to-handle maneuver for the bedside determination of current tube coefficients in the tracheally intubated patient. Based on check-spot measurement of p_trach, current tube coefficients are determined by a least-squares fit procedure valid for the partially obstructed ETT with the indwelling pressure-measuring catheter (PMC). To correct for the removal of the PMC, the relationship between tube coefficients with and those without indwelling PMC has been determined in a laboratory investigation. Accuracy of the procedure was determined during artificial ETT obstruction by comparing calculated with measured_trach. Correspondence between calculated and measured p_trach has been found excellent. We conclude that by adopting this bedside procedure periodically, accurate calculation of p_trach is guaranteed and the advantages of the ATC mode are ensured even in long-term ventilatory support.

A major issue concerning the design and implementation of an image acquisition system for skin lesions is its ability to capture reproducible images. The reproducibility is considered essential for image analysis and for the comparison of sequential images during follow-up studies. This paper describes a prototype image acquisition system that includes a standardized illumination and capturing geometry with polarizing filters and a series of software corrections: Calibration to Black, White and Color for color constancy, Internal camera Parameters adjustment and Pose extraction for stereo vision, Shading correction and Noise Filtering for color quality. The validity of the calibration procedure and the images' reproducibility were tested by capturing sample images in three different lighting conditions: dark, medium and intense lighting. For each case the average values of the three color planes RGB and their standard deviations were calculated; the measured error differences ranged between 0.7 and 12.9 (in the 0–255 scale). Preliminary experiments for stereo measurements provided repeatability of about 0.3∼mm. The above results demonstrate the reproducibility of the captured images at a satisfactory level. The developed prototype was also evaluated clinically, for its ability to support the construction of knowledge-based decision systems and for telemedicine, thus to support telemedical sessions in dermatology.

The development of Intimal Hyperplasia (IH) in saphenous vein coronary artery bypass grafts (SV-CABG) is responsible for the short-term patency of these grafts. Previous studies of SV-CABG models were performed on rigid anastomotic vessels. However, the effects of compliance, bulging and curvature at the anastomosis on the general hemodynamic field, due to compliance and geometric mismatch between the vein and the artery have not been evaluated. We studied axial and transverse velocities by Laser Doppler Velocimetry on a compliant, in vitro, anatomical model of an end-to-side saphenous vein graft (SVG) to left anterior descending (LAD). The model incorporated a bulge at the sinus and curvature at the graft-host junction. Physiologic pressure and flow conditions pertaining to SV-CABG were applied. The presence of the bulge and curvature showed differences in the velocity profiles in comparison with previous rigid model studies. Dynamic separation zones were temporally augmented at the flow divider. The moving stagnation point at the floor of the host vessel was observed to move past the toe of the model during the accelerating portion of the cycle. These findings suggest that the presence of the bulge curvature and compliance may further favor conditions for the development of intimal hyperplasia (IH) at the floor of a CABG.