A System for Detecting Chemically-Induced Changes in Cerebral Blood Flow using Transcranial Doppler Sonography in a Dog Model.
Drues-ME; Hopper-DL; Lange-DN
Proceedings of the Fifth Annual IEEE Symposium on Computer-Based Medical Systems, Durham, North Carolina, June 14-17, 1992, IEEE Computer Society Press 1992:477-485
The effect of deltamethrin (52918635) on cerebral blood flow in the dog was measured by transcranial Doppler sonography (TDS). Each of four greyhound-dogs was administered levels of deltamethrin equivalent to 5% and 10% of the median lethal dose (LD50) by venous cannula. Arterial and venous cannula were implanted for direct blood pressure measurement and a carbon-dioxide (CO2) analyzer was attached to the endotracheal tube to monitor end tidal CO2. The left middle cerebral artery (MCA) was selected for TDS monitoring. Thirty minutes (min) of control readings and 30min of readings after administration of glycerol-formal were taken prior to the administration of the low dose of deltamethrin. After administration, an additional 30min of data were recorded before the dog was taken off anesthesia and allowed to recover. The procedure was repeated 2 to 3 days later with the high dose of deltamethrin in the same dog. Blood flow velocity (BFV) measured by TCD gave a spread of points representing a range of velocities. An algorithm was developed to filter the noise in the BFV data. Immediately following the administration of 7.5% LD50 followed by 10% LD50 deltamethrin, a slight increase in mean arterial pressure, a distinct decrease in mean heart rate and increase in CO2 and in mean (BFV) of 10 to 15min duration were observed. Systolic to diastolic ratio, Pourcelout pulsatility index, Golsing pulsatility index, and maximum systolic upstroke showed no consistent changes. Similar results were obtained with the spaced, high and low exposures to deltamethrin. The authors conclude that TCD has the sensitivity to detect early deltamethrin induced changes in BFV, but that improvements are needed for the extension of this method to the early detection of toxic exposures.
NIOSH-Grant; Grants-other; In-vivo-study; Laboratory-animals; Insecticides; Biological-monitoring; Physiological-measurements; Analytical-methods; Sonar-signals;
Biomedical Engineering Iowa State University 1146 Veterinary Medicine Ames, IA 50011
Other Occupational Concerns; Grants-other;
Proceedings of the Fifth Annual IEEE Symposium on Computer-Based Medical Systems, Durham, North Carolina, June 14-17, 1992, IEEE Computer Society Press
Iowa State University of Science & Tech, Ames, Iowa