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Full-Text Articles in Biomedical Engineering and Bioengineering
Relationship Of Blood Pressure And Flow During Cpr To Chest Compression Amplitude: Evidence For An Effective Compression Threshold, Charles F. Babbs, W D. Voorhees, K R. Fitzgerald, H R. Holmes, L A. Geddes
Relationship Of Blood Pressure And Flow During Cpr To Chest Compression Amplitude: Evidence For An Effective Compression Threshold, Charles F. Babbs, W D. Voorhees, K R. Fitzgerald, H R. Holmes, L A. Geddes
Weldon School of Biomedical Engineering Faculty Publications
This study was conducted to investigate the importance of the depth of chest compression in producing effective cardiopulmonary resuscitation (CPR) in animals, as indicated by cardiac output and mean arterial blood pressure. Cardiac output was measured by a modified indicator dilution technique in 8 anesthetized dogs, 6 to 12 kg body weight, during repeated 2-minute episodes of electrically induced ventricular fibrillation and CPR provided by a mechanical chest compressor and ventilator (Thumper®). Chest compression exceeding a threshold value (x0) between 1.5 and 3.0 cm was required in each animal to produce measurable cardiac output. In particular, …
Effects Of Myocardial Infarction On Catheter Defibrillation Threshold, Charles F. Babbs
Effects Of Myocardial Infarction On Catheter Defibrillation Threshold, Charles F. Babbs
Weldon School of Biomedical Engineering Faculty Publications
Because the automatic implantable defibrillator may be used in patients having ischemic heart disease, it is important to know whether myocardial ischemia changes the threshold for ventricular defibrillation under experimental conditions simulating automatic internal defibrillation. We determined changes in ventricular defibrillation threshold following coronary occlusion, using an electrode catheter designed for use with an automatic implantable defibrillator. Acute myocardial ischemia was produced without thoracotomy in 10 dogs (experimental group) by embolization with a plastic bead injected via a catheter into the left coronary artery. A control group of 4 dogs had only saline injected into the artery. Defibrillation threshold was …
Simple Methods For Determining The Accuracy Of Tumor Blood Flow Measurements Using Radioactive Microspheres In Rats, Rosanna C. Chan, Charles F. Babbs, Richard J. Vetter
Simple Methods For Determining The Accuracy Of Tumor Blood Flow Measurements Using Radioactive Microspheres In Rats, Rosanna C. Chan, Charles F. Babbs, Richard J. Vetter
Weldon School of Biomedical Engineering Faculty Publications
Two simple methods are presented that allow positive identification of the accuracy and precision of the microsphere technique and a quick verification of sphere entrapment in tumor vessels. A known flow of Ringer's solution from a motor-driven syringe is perfused through the rat's isolated systemic circulation from left ventricle to right atrium and collected in a funnel. Using this preparation, total blood flow in rats measured with radioactive microspheres injected into the left ventricle was 97% of actual flow. The coefficient of variation (standard deviation/mean) of the microsphere measurements was 0.22. In the same preparation, non-entrapment of microspheres in subcutaneous …
Improved Oxygen Delivery During Cardiopulmonary Resuscitation With Interposed Abdominal Compressions, William D. Voorhees, Mark J. Niebauer, Charles F. Babbs
Improved Oxygen Delivery During Cardiopulmonary Resuscitation With Interposed Abdominal Compressions, William D. Voorhees, Mark J. Niebauer, Charles F. Babbs
Weldon School of Biomedical Engineering Faculty Publications
The ability of a new modification of cardiopulmonary resuscitation (CPR) to deliver oxygen to tissues was evaluated. The method utilizes standard CPR techniques with the addition of manual abdominal compressions (100 mm Hg) interposed between chest compressions, and is termed interposed abdominal compression-CPR (IAC-CPR). Oxygen delivery was measured by a spirometer in a closed circuit designed to permit positive-pressure ventilation synchronized with mechanical chest compression. Ventricular fibrillation was induced electrically in 10 anesthetized dogs. In each dog, trials of IAC-CPR and standard CPR were alternated every five minutes during a 30-minute period. Arterial and central venous blood pressures, oxygen consumption, …
Bioassays- Procedures And Results, A. F. Maciorowski, L. W. Little, L. F. Raynor, Ronald C. Sims, J. L. Sims
Bioassays- Procedures And Results, A. F. Maciorowski, L. W. Little, L. F. Raynor, Ronald C. Sims, J. L. Sims
Biological Engineering Faculty Publications
Bioassay procedures to describe, evaluate, and predict the potential hazard of toxic materials to organisms and ecosystems, and the health-related aspects of polluted waters continue to receive widespread attention. Symposium proceedings and books pertinent to toxic substances management and test procedures have appeared, as have several literature reviews pertinent to specific pollutants. The proceedings of the fifth annual ASTM symposium on aquatic toxicology presented a collection of papers directed to research needs in aquatic toxicology and hazard assessment, new concepts in aquatic toxicology, biological availability and sediment toxicity, and hazard assessment and water quality criteria.1 A state-of-the-art overview pertinent …
Yield Comparisons Between Continuous No-Till And Tillage Rotations, Elbert C. Dickey, Thomas Peterson, J. R. Gilley, L. N. Mielke
Yield Comparisons Between Continuous No-Till And Tillage Rotations, Elbert C. Dickey, Thomas Peterson, J. R. Gilley, L. N. Mielke
Biological Systems Engineering: Papers and Publications
Continuous use of no-till planting systems may result in reduced yields, especially on finer textured soils that tend to be poorly drained. Soil compaction and poor soil aeration have been identified as possible factors contributing to the lower yields. Research conducted to evaluate tillage rotations on these soils shows that periodic use of the moldboard plow can result in statistically higher yields as compared to continuous no till. However, use of chisel plow and disk tillage systems following three years of continuous no-till did not result in yield increases. A relationship between cone penetrometer index and yield indicates a trend …
Effects Of Tillage On Soil Erosion In A Wheat-Fallow Rotation, Elbert C. Dickey, C. R. Fenster, J. M. Laflen, R. H. Mickelson
Effects Of Tillage On Soil Erosion In A Wheat-Fallow Rotation, Elbert C. Dickey, C. R. Fenster, J. M. Laflen, R. H. Mickelson
Biological Systems Engineering: Papers and Publications
Erosion from alternative tillage systems in winter wheat-fallow rotations was measured using a rainfall simulator. The Nebraska study, conducted at the High Plains Agricultural Laboratory, showed that during the fallow period between harvest and tillage, soil erosion was not affected by the tillage systems studied. However, erosion following tillage was different for the systems evaluated and moldboard plowing with the slope had the largest amount. The no-till system reduced erosion by about 95% during this period. Although contour plowing was effective in reducing erosion when compared to plowing with the slope, no differences were measured between with the slope and …