Biomedical subjects

R E Dugdale

Publications and source records attributed to R E Dugdale.

5 recordsLinked to original sources

PubMed1998

Measurement of the volume of a leg ulcer using a laser scanner.

Effective management of leg ulcer healing depends on accurate and reliable measurements of wound size. Current techniques usually rely on estimates of surface area or circumference which do not fully describe the healing process. A novel instrument has been developed that is capable of measuring the variations in the surface contours (topography) of a solid object. Its primary application is to measure the size of a leg ulcer by scanning a laser displacement sensor over the affected area. There is no contact with the wound and scanning takes approximately 2 minutes to perform. Volume is calculated by subtracting the measured topography from one calculated using an algorithm to reconstruct a healthy leg surface. A study was carried out where patients had their ulcers scanned during their visits to the leg ulcer clinic. Data are presented from two venous leg ulcers showing the calculated volume reducing over time.

Humans↗

PubMed1994

Measuring leg ulcers using a laser displacement sensor.

A non-contact method for the measurement of a skin ulcer's area and volume has been developed. A commercially available laser displacement sensor is scanned across the ulcer's surface to produce a displacement image. From this image the healthy normal skin's surface is reconstructed and the area and volume found. Results of measurements made with phantom ulcers show that the method has a precision and accuracy +/- 5% of the total size. This compares favourably with results from other non-contact methods that have been published. The method of measurement is simple and reliable. At present, the time taken to produce a displacement image is lengthy but this is due to a limitation in the instrumentation, rather that a failing of the technique. The result of a preliminary measurement made on a patient's leg ulcer is presented.

Humans↗

PubMed1988

Closed-loop control of the partial pressure of arterial oxygen in neonates.

A closed-loop control system has been developed to regulate automatically the partial pressure of arterial oxygen (PaO2) to a pre-set level in neonates with RDS (Respiratory Distress Syndrome). A microcomputer-based system is described which uses the PaO2 value from an indwelling umbilical artery electrode as the input to a robust control algorithm. The derived control signal is used to modify the position of a motor driven oxygen/air blender, thus regulating the percentage of oxygen delivered in the inspired gas mixture. The parameters of the control algorithm were conservatively chosen, and the safety aspects of the system are discussed. A total of 48 h of closed-loop control were recorded on seven pre-term infants with mild-to-moderate RDS being nursed in headboxes. Ten separate closed-loop control intervals were recorded, and overall the results showed a marked improvement over comparable periods of manual control. The percentage of time for which the recorded PaO2 was within +/- 1 kPa of the chosen target value (10 kPa) was 74.9 +/- 10.2% when averaged over the ten closed-loop control periods. The corresponding figure for the comparable manual control intervals was 45.2 +/- 16.0%.

Algorithms↗

PubMed1983

A cotside microcomputer monitoring system for use in the neonatal intensive care unit.

A dedicated cotside microcomputer unit is described. It is designed to collect and to display graphically all continuously recorded variables from an infant in a neonatal intensive care unit. The data are collected from existing monitoring equipment and the graphical displays demonstrate both short and long term trends in data. In addition, the system allows data collected intermittently to be entered on a simple keyboard and to be displayed on plots that are time-correlated with the on-line data displays. A permanent record of the monitoring interval may be generated and the facility for closed-loop control of the partial pressure of arterial oxygen is being developed for integration into the system.

Computers↗

PubMed1979

Sensitometry of films for nuclear medicine.

A method is described for the determination of characteristic curves for films used in nuclear medicine imaging. Such characteristic curves are presented for a number of commercially available film types and their significance is discussed.

Physical Phenomena↗