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1984

Weldon School of Biomedical Engineering Faculty Publications

Articles 1 - 9 of 9

Full-Text Articles in Engineering

Irradiation-Hyperthermia In Canine Hemangiopericytomas: Large-Animal Model For Therapeutic Response, Ralph C. Richardson, Virgil L. Anderson, William D. Voorhees, William E. Blevins, Tammy K. Inskeep, Wolfgang Janas, Robert E. Shupe, Charles F. Babbs Nov 1984

Irradiation-Hyperthermia In Canine Hemangiopericytomas: Large-Animal Model For Therapeutic Response, Ralph C. Richardson, Virgil L. Anderson, William D. Voorhees, William E. Blevins, Tammy K. Inskeep, Wolfgang Janas, Robert E. Shupe, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Results of irradiation-hyperthermia treatment in 11 dogs with naturally occurring hemangiopericytomas are reported. Similarities of canine and human hemangiopericytomas are described. Orthovoltage X-irradiation followed by microwaveinduced hyperthermia resulted in a 91% objective response rate. A statistical procedure was given to evaluate quantitatively the clinical behavior of locally invasive, nonmetastatic tumors in dogs that were undergoing therapy for control of local disease. The procedure used a small sample size and demonstrated distribution of the data on a scaled response as well as transformation of the data through classical parametric and nonparametric statistical methods. These statistical methods set confidence limits on the …

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An Experimental Circulatory Arrest Model In The Rat To Evaluate Calcium Antagonists In Cerebral Resuscitation, Lawrence De Garavilla, Charles F. Babbs, Willis A. Tacker Jan 1984

An Experimental Circulatory Arrest Model In The Rat To Evaluate Calcium Antagonists In Cerebral Resuscitation, Lawrence De Garavilla, Charles F. Babbs, Willis A. Tacker

Weldon School of Biomedical Engineering Faculty Publications

A circulatory arrest model in the rat was developed for use in cerebral and cardiac resuscitation studies. Whole-body ischemia was produced for 8 to 18 minutes by arresting the heart with a cold potassium chloride cardioplegic solution. Following cardiopulmonary resuscitation, minimal, standardized intensive care was provided. As the duration of ischemia was increased from 8 to 18 minutes, survival immediately following resuscitation decreased from 100% to 25%, and survival at 48 hours after ischemia decreased from 80% to 0%. Thirty per cent of the rats recovering from 11 minutes of ischemia suffered motor seizures. Survival and the incidence of motor …

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Preclinical Studies Of Abdominal Counterpulsation In Cpr, Charles F. Babbs Jan 1984

Preclinical Studies Of Abdominal Counterpulsation In Cpr, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Abdominal counterpulsation added to standard cardiopulmonary resuscitation improves blood flow in animal models when compared to chest compressions alone. Similar effects can be demonstrated in analog and digital computer models of the circulation. The technique generates both central aortic and central venous pressure pulses, and successful application of the method depends on maximizing the former and minimizing the latter. Proper technique is important in order to generate the largest possible arteriovenous pressure difference.

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Theoretical Advantages Of Abdominal Counterpulsation In Cpr As Demonstrated In A Simple Electrical Model Of The Circulation, Charles F. Babbs, Sandra H. Ralston, Leslie A. Geddes Jan 1984

Theoretical Advantages Of Abdominal Counterpulsation In Cpr As Demonstrated In A Simple Electrical Model Of The Circulation, Charles F. Babbs, Sandra H. Ralston, Leslie A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

Animal studies and preliminary clinical observations suggest that the addition of interposed abdominal compressions (IAC) to ventilation and chest compression of standard cardiopulmonary resuscitation (CPR) augments blood flow, blood pressures, and immediate survival. To investigate the physical basis for enhanced circulation during IAC-CPR, we developed an electrical model of the circulation. Heart and blood vessels were modeled as resistive-capacitive networks, pressures as voltages, blood flow as electric current, blood inertia as inductance, and the cardiac and venous valves as diodes. External pressurization of the heart and great vessels, as would occur in CPR, was simulated by application by half-sinusoidal voltage …

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Efficacy And Safety Of The Reciprocal Pulse Defibrillator Current Waveform, M J. Niebauer, Charles F. Babbs, L A. Geddes, J D. Bourland Jan 1984

Efficacy And Safety Of The Reciprocal Pulse Defibrillator Current Waveform, M J. Niebauer, Charles F. Babbs, L A. Geddes, J D. Bourland

Weldon School of Biomedical Engineering Faculty Publications

The efficacy and safety of a new defibrillating current waveform, consisting of a low-tilt 5 ms trapezoidal pulse followed closely by a second identical pulse of opposite polarity, was tested m seven isolated, perfused, working canine hearts suspended in an isoresistive, isosmotic shock bath at 37 oC. The efficacy and safety of the reciprocal pulse was compared with a single 5 ms pulse, a single 10 ms pulse, and a dual (unidirectional) 5 ms pulse waveform. The mean threshold average current densities for the 5 ms single pulse, 10 ms single pulse, dual 5 ms pulse, and reciprocal pulse (absolute …

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Cardiac, Thoracic, And Abdominal Pump Mechanisms In Cardiopulmonary Resuscitation: Studies In An Electrical Model Of The Circulation, Charles F. Babbs, Christopher Weaver, Sandra H. Ralston, Leslie A. Geddes Jan 1984

Cardiac, Thoracic, And Abdominal Pump Mechanisms In Cardiopulmonary Resuscitation: Studies In An Electrical Model Of The Circulation, Charles F. Babbs, Christopher Weaver, Sandra H. Ralston, Leslie A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

To investigate alternative mechanisms generating artificial circulation during cardiopulmonary resuscitation (CPR), an electrical model of the circulation was developed. Heart and blood vessels were modeled as resistive-capacitive networks; pressures in the chest, abdomen, and vascular compartments as voltages; blood flow as electric current; blood inertia as inductance; and the cardiac and venous valves as diodes. External pressurization of thoracic and abdominal vessels, as would occur in CPR, was simulated by application of half-sinusoidal voltage pulses. Three modes of creating artificial circulation were studied: cardiac pump (CP), in which the atria and ventricles of the model were pressurized simultaneously; thoracic pump …

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Intrapulmonary Epinephrine During Prolonged Cardipulmonary Resuscitation: Improved Regional Blood Flow And Resuscitation In Dogs, Sandra H. Ralston, William D. Voorhees, Charles F. Babbs Jan 1984

Intrapulmonary Epinephrine During Prolonged Cardipulmonary Resuscitation: Improved Regional Blood Flow And Resuscitation In Dogs, Sandra H. Ralston, William D. Voorhees, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Blood flow to vital organs was measured at five-minute intervals during 20 minutes of cardiopulmonary resuscitation (CPR) and ventricular fibrillation in two groups of anesthetized dogs (n = 15 per group). The relationship between organ blood flow and restoration of circulation after 20 minutes was assessed with no additional treatment in Group I and with intrapulmonary epinephrine in Group II. Cardiac output and organ blood flow did not vary significantly in Group I. In Group II, intrapulmonary epinephrine significantly improved blood flow to the myocardium, the brain, and the adrenal glands. A mean myocardial blood flow of less than 0.13 …

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Regional Blood Flow During Cardiopulmonary Resuscitation With Abdominal Counterpulsation In Dogs, William D. Voorhees Iii, Sandra H. Ralston, Charles F. Babbs Jan 1984

Regional Blood Flow During Cardiopulmonary Resuscitation With Abdominal Counterpulsation In Dogs, William D. Voorhees Iii, Sandra H. Ralston, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The addition of abdominal counterpulsation to standard cardiopulmonary resuscitation (IAC-CPR) during ventricular fibrillation has been shown to improve cardiac output, oxygen uptake, and central arterial blood pressure in dogs. The present study was performed to determine the effect of IAC-CPR on regional blood flow. Regional blood flow was measured with radioactively labeled microspheres during sinus rhythm and during alternate periods of IAC-CPR and standard CPR (STD-CPR) in nine dogs anesthetized with pentobarbital. Blood pressures and oxygen uptake were measured continuously. As in previous studies, diastolic arterial pressure was higher (30.8%) during IAC-CPR than during STD-CPR, as were cardiac output (24.5%) …

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Abnormal Response Of Tumor Vasculature To Vasoactive Drugs, Rosanna C. Chan, Charles F. Babbs, Richard J. Vetter, Carlton H. Lamar Jan 1984

Abnormal Response Of Tumor Vasculature To Vasoactive Drugs, Rosanna C. Chan, Charles F. Babbs, Richard J. Vetter, Carlton H. Lamar

Weldon School of Biomedical Engineering Faculty Publications

The effects of the vasoconstrictor, phenylephrine, and the vasodilator, hydralazine, on blood flow to tumor were studied and compared to those on blood flow to normal tissues in vivo. Regional blood flow and cardiac output were measured with the use of radioactive microspheres in 150- to 250 g inbred Harlan F344 rats bearing subcutaneous nodules of two types of transplantable carcinoma ("hard" and "soft") with microscopically different vascular patterns. Three groups of rats were treated with hydralazine, saline, or phenylephrine, and regional blood flow was determined at the time of maximum blood pressure response. Results were correlated with quantitative morphometric …

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