Engineering Commons^™

Influence Of Interposed Ventilation Pressure Upon Artificial Cardiac Output During Cardiopulmonary Resuscitation In Dogs, 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 determine the effects of high pressure interposed ventilations during cardiopulmonary resuscitation (CPR). Cardiac output was measured by a modified indicator dilution technique in eight anesthetized, intubated mongrel dogs. Positive pressure ventilations (12/min, 80% O2) were interposed after every five chest compressions (performed at 62/min) by a mechanical chest compressor (Thumper®). On repeated trials in the same animal, ventilation pressures from 10-50 cm of H2O were tested in randomized sequence, while the technique of chest compression was held constant. Arterial blood gases immediately after resuscitation were monitored. Increasing ventilation pressure had surprisingly little effect on cardiac …

Evaluation Of The Operating Internal Resistance And Capacitance Of Intact Trapezoidal Waveform Defibrillators, Charles F. Babbs, Sj Whistler, La Geddes

Weldon School of Biomedical Engineering Faculty Publications

No abstract provided.

Regional Blood Flow During Cardiopulmonary Resuscitation In Dogs, W D. Voorhees, Charles F. Babbs, W A. Tacker

Weldon School of Biomedical Engineering Faculty Publications

To determine differences in regional blood flow during cardiopulmonary resuscitation (CPR) versus normal cardiac function, we measured regional blood flow to sev~ral organs in 19 pentobarbital-anesthetized dogs (6-12 kg). Regional blood flow was measured during sinus rhythm in 5 dogs and during electrically induced ventricular fibrillation with CPR in the other 14 dogs. Regional blood flow and cardiac output were measured using radioactively labelled polystyrene microspheres of 15 ±3P diameter, injected into the left ventricle. Adequacy of microsphere mixing at low cardiac outputs was verified by comparing flow rates to paired organs. Cardiac output was 175 ml/kg/min during sinus rhythm …

Therapeutic Indices For Transchest Defibrillator Shocks: Effective, Damaging, And Lethal Electrical Doses, Charles F. Babbs, Willis A. Tacker, John F. Vanvleet, Joe D. Bourland, Leslie A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

Although prospective studies of defibrillator shock overdose cannot be performed in man, the therapeutic indices of various defibrillating current waveforms can be measured in animals. We determined the ratios TD50/ED50 and LD50/ ED50 (where TD50 = median "toxic" or damageinducing dose, ED50 = median effective or defibrillating dose, and LD50 = median lethal dose) as measures of the therapeutic index for damped sine wave defibrillator shocks in dogs. Death of an animal and/or any degree of cardiac damage found by gross or microscopic examination were defined as harmful effects of shock, analogous to drug toxicity. In terms of peak current, …

An Animal Model For Testing Automatic Defibrillators, J D. Bourland, Charles F. Babbs, W A. Tacker, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

A promising therapy for ventricular fibrillation--a life-threatening cardiac arrhythmia--is the implantation of an automatic defibrillator. A critical component of such a device is the system that detects the presence of ventricular fibrillation. Automatic systems for detecting ventricular fibrillation have been tested with arrhythmias produced by electric shocks in normal canine hearts, but have not been tested with spontaneous arrhythmias in hyperirritable hearts. We have developed an animal model to create arrhythmias without electrical stimulation and have used it to test our automatic defibrillator. This model permits evaluation of both reliability to diagnose ventricular fibrillation and reliability to reject other tachyarrhythmias.

A New Technique For Repeated Measurement Of Cardiac Output During Cardiopulmonary Resuscitation, L A. Geddes, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

We have developed a method for measurement of cardiac output during CPR with ventricular fibrillation. The method avoids the problems encountered when conventional techniques are used under the conditions of very low cardiac output. The method consists of injecting 5% saline as the indicator into the left ventricle and detecting its appearance in the descending aorta by withdrawing blood through an electrically calibrated conductivity cell. The adequacy of indicator mixing has been verified by obtaining dilutions curves simultaneously from the brachial and femoral arteries. Cardiac output can be determined even when output is as low as 7 ml/min/kg during CPR …

Influence Of Adrenergic Drugs Upon Vital Organ Perfusion During Cpr, H R. Holmes, Charles F. Babbs, W D. Voorhees, W A. Tacker, B De Garavilla

Weldon School of Biomedical Engineering Faculty Publications

To determine whether adrenergic drugs administered during cardiopulmonary resuscitation (CPR) alter the distribution of artificial card:l.ac output, we measu"red regional blood flow and cardiac output using radioactive microspheres in 12 dogs. Ventricular fibrillation was induced electrically and CPR was immediately begun with a mechanical chest compressor and ventilator (Thurn per ( R) ) at 60 compressions/min, with a ventilation:compression ratio of 1:5, a compression duration of 0.5 sec, and a ventilation pressure of 20 em H 2 o. Compression force was sufficient to develop 40-50 mmHg peak intraesophageal pressure. After 30 sec of CPR, either 0.9% saline vehicle or 50 …

Dependence Of Defibrillation Threshold Upon Extracellular/Intracellular K+ Concentrations, Charles F. Babbs, S J. Whistler, G Yim, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

The effect of increasing extracellular potassium concentration (K_o) upon electrical ventricular defibrillation threshold was investigated in pentobarbital anesthetized dogs treated with intravenous potassium chloride. Defibrillation threshold fell during potassium intoxication. The percent decrease in defibrillation threshold was linearly related to the logarithm of K_o and to the potassium equilibrium potential, E_K, calculated from measured extracellular and intracellular potassium concentrations of ventricular muscle. In dogs supported by left ventricular bypass in order to maintain the circulation during potassium intoxication, the values of K_o and E_K required for spontaneous, K⁺ induced defibrillation (electrical defibrillation …

Dynamic Intraesophageal Imagining Of The Heart With Ultrasound, N E. Fearnot, Charles F. Babbs, J D. Bourland, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

Real-time images of the heart from within the esophagus are produced by a new intraesophageal ultrasonic sector scanner. Sixty images per second are displayed on a gray scale CRT in real-time and recorded on standard videotape for review. By interactive positioning of the esophageal probe, heart ventricles, atria, and valves can be visualized and their dynamics can be studied. The esophageal probe comprises four 5 MHz PZT-5 piezoelements of 6.35 mm diameter, mounted on a shaft that rotates at 900 rpm. The piezoelements are pulsed at a 5 kHz rate and the echoes are processed electronically.

New Versus Old Theories Of Blood Flow During Cpr, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Today, the physiology of blood flow during external chest compression appears more complicated than had previously been imagined. New evidence requires that at least two possible mechanisms be considered for generating artificial circulation by external chest compression. The first is the classical mechanism in which the heart propels blood because it is squeezed between the sternum and the spine. The second is a more recently appreciated mechanism in which the entire thorax acts as a pump because of global intrathoracic pressure changes. The first might be called the cardiac pump mechanism and the second might be called the thoracic pump …

Design Of Vegetative Filters For Feedlot Runoff Treatment In Humid Areas, D. H. Vanderholm, Elbert C. Dickey

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The vegetative filter approach uses overland flow or shallow channelized flow to treat feedlot runoff by infiltration, dilution and filtration. Based on extensive monitoring of four field systems in Illinois over a two year period, acceptable performance standards were selected. Design criteria to meet the standards were developed for both the overland flow vegetative filters and the channelized or serpentine terrace filters. A major design criterion for both types of vegetative filters is the time required for applied runoff to flow the length of the filter.

An alternative to using zero-discharge treatment systems to control feedlot runoff is to replace …

Home Sewage Treatment Systems, Elbert C. Dickey, Robert P. Pharris, Phillip W. Harlan, Gary Hosek

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Homeowners in areas not served by municipal sewage treatment systems face a problem of providing safe and effective wastewater treatment systems for their homes.

There are several methods currently available for proper treatment of home sewage, including septic tank absorption fields, mounds, lagoons, aerobic treatment units and others. These systems and their advantages and disadvantages are discussed in this NebGuide.

Treatment and disposal of domestic sewage is of concern because of the variety of pathogenic organisms contained in sewage. These include bacteria, viruses, and other microorganisms that come from the digestive tract, respiratory tract, and skin of man. Some of …

Center Pivot Irrigation In Nebraska: An Institutional Analysis Case Study, Thomas Nutt-Powell, Stewart Landers

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This paper is one of a series resulting from institutional analysis of photovoltaic (PV) acceptance. It reports the results of a study of institutional factors influencing acceptance of center-pivot irrigation in the Nebraska agricultural community. Center-point irrigation (CP) was an interesting topic for study because (1) it was a major recently introduced technological innovation in agriculture which (2) had potentially detrimental attributes – water and energy intensity. A brief historical review of the introduction and acceptance of center-pivot irrigation in the Nebraska agricultural community is presented. Institutions which were a likely part of this institutional arena relative to CP introduction …

A Pressure Injection Device For Inoculation Of Maize With Bacterial Phytopathogens, Randall R. Carlson, A. K. Vidaver, David S. Wysong, J. H. Riesselman

Biological Process Development Facility: Staff Publications

A pressure injection device (PID) was used to inoculate maize (Zea mays) with bacterial phytopathogens. The PID was evaluated for its speed, effectiveness, and precision relative to the needle-eye method of inoculation. Corynebacterium nebraskense, Erwinia stewartii, and Pseudomonas andropogonis were each used successfully as inocula to infect maize and produce symptoms typical of Goss's wilt, Stewart's wilt and bacterial stripe, respectively. Quantitative inoculation with the PID was faster and as statistically precise as using a calibrated needle-eye.

A Comparative Analysis Of Intrusion Of Incisor Teeth Achieved In Adults And Children According To Facial Type, Ronald L. Otto

Loma Linda University Electronic Theses, Dissertations & Projects

A comparison of incisor intrusion achieved in deep bite adults and children was made. Facial type was also examined for affect upon intrusion achieved. Fifty-five cases treated with Bioprogressive mechanics were studied cephalometrically, including twenty-four adults and thirty-one children. Neither age nor facial type was found to be statistically related to the amount of incisor intrusion achieved in this sample. A method of measuring intrusion at the root apices was devised which was felt to give a more accurate indication of actual bodily intrusion. More external root changes during treatment were observed for adults than for growing children. Wide latitude …

Maintaining A Septic Tank System, Elbert C. Dickey, Gary Hosek, Phillip W. Harlan

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Once a septic tank and absorption field are installed, you can do several things to prolong their life, thus protecting an investment which may cost $2500 or more. Here are several tips you can follow.

Often overlooked or neglected is the fact that septic tanks should be inspected at least once annually. In every properly functioning septic tank, sludge accumulates in the bottom. This sludge is composed of solid materials and must be removed periodically. If the sludge is not removed, the accumulated solids will build up in the septic tank and will begin to wash out into the absorption …

A Septic Tank System For Sewage Treatment, Elbert C. Dickey, Phillip W. Harlan, Gary Hosek

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A properly designed, installed ao1d maintained septic tank system is an approved method of sewage treatment for private residences in rural or urban areas where public sewage treatment systems are not available. The components of a septic system are the house sewer, the septic tank and the absorption field, as illustrated in Figure 1. Sewage flows to the septic tank through the house sewer. In the septic tank, the solids are separated from the liquids, undergo anaerobic digestion and are stored as sludge at the bottom of the tank. The liquid (septic tank effluent) flows to the absorption field …

Attenuation And Speed Of 10 Mhz Ultrasound In Canine Blood Of Various Packed Cell Volumes At 37c, D J. Hughes, L A. Geddes, Charles F. Babbs, J D. Bourland, V L. Newhouse

Weldon School of Biomedical Engineering Faculty Publications

The attenuation coefficient and the speed of 10 MHz ultrasound were determined in canine blood at 37 oC by a differential path length technique. Blood specimens with packed cell volumes (PCV) ranging from 0 to 53% were prepared by separating the cells from the plasma and mixing the two components. The mean attenuation coefficient increased linearly with packed cell volume, the least squares regression function being  (dB/cm) = 0.992 +0.039 PCV with a standard error of the estimate = 0.255. The speed of 10 MHz ultrasound, c, in millimetres per second, increased with packed cell volume, the regression function …

Elevation Of Ventricular Defibrillation Threshold In Dogs By Antiarrhythmic Drugs, Charles F. Babbs, Gkw Yim, S J. Whistler, W A. Tacker, L A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

Effects of antiarrhythmic drugs upon the threshold delivered energy (TDE) and threshold peak current (TPC) for electrical ventricular defibrillation by damped sinusoidal shocks were investigated in 25 pentobarbital-anesthetized dogs. TDE and TPC were increased by the three antiarrhythmic drugs tested. Bolus injections produced a transient rise, and continuous infusions produced a steady rise in defibrillation threshold. The maximal percent elevations in mean defibrillation threshold during the 60 minutes after intravenous drug treatment in groups of n = 5 dogs were: Treatment % increase in TDE % increase in TPC Lidocaine bolus (3 mg/kg) 48 26 Lidocaine (0.5 mg/Kg/min) 99 45 …

Measurements Of Young's Modulus Of Elasticity Of The Canine Aorta With Ultrasound, D J. Hughes, Charles F. Babbs, L A. Geddes, J D. Bourland

Weldon School of Biomedical Engineering Faculty Publications

We have developed an ultrasonic technique for determining the dynamic Young's modulus of elasticity (E) of the canine aorta in vivo. Young's modulus was measured in the descending thoracic aorta (DTA) and the abdominal aorta (AA) of 12 dogs over a range of mean blood pressures from 40-200 mmHg. The vessels were excised and dynamic moduli were determined in vitro postmortem from pressure-volume curves. The data so obtained were compared to the in vivo values. In vivo and in vitro moduli increased exponentially with mean distending pressure (P). The equation of best fit for these data was of the form …

Micro-Relief Surface Depression Storage: Changes During Rainfall Events And Their Application To Rainfall-Runoff Models, J. Kent Mitchell, Benjamin A. Jones Jr.

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Micro-relief surface depression storage is one of the dynamic components of the rainfall-runoff process. The quantification of the effect of rainfall intensity and duration on the micro-relief was the subject of this study. Micro-relief measurements were made on 88 soil bin samples before and after the application of simulated rainfall events. The surface depression changes are described with empirical equations, using basic rainfall, surface hydrology, and soil parameters and their cross products as independent variables. A rainfall-runoff model demonstrates the value of a dynamic description of the surface depression storage function.

Wells And Ponds: Water Quality And Supply, Elbert C. Dickey, W.D. Lembke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

FARM WELLS IN WASHINGTON COUNTY ...................... 1

Study Area Description ................................. 4

Field and laboratory Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . 9

Soil and Groundwater Measurements ...................... 10

Well Water Measurements ............................... 15

Summary ............................................ 17

PONDS IN WASHINGTON AND POPE COUNTIES ................. 17

Ponds in Washington County ............................ 17

Ponds and a Lake in Pope County ......................... 25

Summary ............................................ 30

Bibliography ............................................. 31

Appendix ............................................... 34

This bulletin is one of six publications growing out of a four-and …

Sizing Of Liquid Manure Tank Wagons And The Economic Evaluation Of Liquid Manure Injection, J.N. Scarborough, Elbert C. Dickey, D. H. Vanderholm

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Liquid manure tank wagons were evaluated on a cost basis to determine the optimum size for a given livestock operation. Also the economics of adding a liquid injector to the tank wagon was studied for profitability.

INTRODUCTION

The proper selection of a liquid manure tank wagon is a problem faced by many progressive livestock producers with liquid manure systems. Selection of a manure tank wagon is usually based on the farmer's or dealer's opinion of what size is right rather than on a logical analysis including an economic analysis of the costs involved. This paper provides guidelines for selecting the …

Leaf Spot Of Field Corn Caused By Pseudimonas Andropogonis, Anne K. Vidaver, Randall R. Carlson

Biological Process Development Facility: Staff Publications

A leaf spot of field corn was shown to be caused by the bacterium Pseudomonas andropogonis. Leaf spot symptoms were observed over 3 years in several States. Inoculation of corn by vacuum infiltration of the bacteria was necessary to reproduce field symptoms.

A bacterial leaf spot disease of different cultivars of field corn was observed in early summer of 1973, 1974, and 1975. Leaves with essentially the same symptoms were obtained from South Dakota, Iowa, Kansas, Nebraska, and Michigan. The same symptoms were also seen in Wisconsin. Symptoms consisted of circular to ellipsoidal, tan to brown spots, with irregular …

Effect Of Pentobarbital Anesthesia On Ventricular Defibrillation Threshold In Dogs, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The effect of pentobarbital anesthesia upon the minimal voltage and current required for electrical ventricular defibrillation (the defibrillation threshold) was investigated in dogs. Threshold current, energy, and charge in five dogs averaged 2 per cent, 13 per cent, and 6 per cent less under surgical levels of pentobarbital anesthesia than thresholds in the same animals in the awake, unanesthetized state. In dogs given sufficient pentobarbital to produce apnea and supported by mechanical ventilation, threshold current, energy, and charge averaged 3 per cent, 17 per cent, and 2 per cent less than comparable awake values. These differences were far from statistically …

Protection Of Ischemic Myocardium By Whole-Body Hypothermia After Coronary Artery Occlusion In Dogs, Dana R. Abendschein, Willis A. Tacker Jr, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Anesthetized dogs were cooled to a core body temperature of 26°C or maintained at a body temperature of 37°C during periods of 5 and 10 hours of LAD coronary artery occlusion. Subsequent macroscopic dehydrogenase enzyme mapping showed that ischemic injury was 25 per cent less after 5 hours of coronary occlusion and 20 per cent less after 10 hours of occlusion in hypothermic dogs than in normothermic controls. The heart rate and left ventricular minute work in hypothermic dogs decreased to roughly half the levels measured in normothermic animals, while left ventricular contractility was 10 to 40 per cent lower …

Evaluation Of The Operating Internal Resistance, Inductance, And Capacitance Of Intact Damped Sine Wave Defibrillators, Charles F. Babbs, S J. Whistler

Weldon School of Biomedical Engineering Faculty Publications

A method is developed for determining actual values of circuit elements in a damped sine wave (Lown waveform) defibrillator, solely from measurements of the output, using two or more power resistors and a storage oscilloscope. If a defibrillator containing capacitance, C, inductance, L, and internal resistance, Ri, is discharged into increasing 5- to 100-ohm resistive loads, R, it is shown for underdamped output waveforms that aˆ = Ri/2L + R/2L and cˆ = CRi + CR, where aˆ = /[t2 tan(t1/t2)], cˆ = 2 aˆ /[ 2 aˆ + (/t2)2], t1 = time from onset to peak, and t2 = …

Temporal Stability And Precision Of Ventricular Defibrillation Threshold Data, Charles F. Babbs, S J. Whistler, G Yim

Weldon School of Biomedical Engineering Faculty Publications

Over two-hundred measurements of the minimum damped sinusoidal current and energy for transchest electrical ventricular defibrillation (ventricular defibrillation threshold) were made to determine the stability and precision of threshold data in 15 pentobarbital-anesthetized dogs. Threshold was determined by repeated trials of fibrillation and defibrillation with successive shocks of diminishing current, each 19% less than that of the preceeding shock. The lowest shock intensity that defibrillated was defined as threshold. In three groups of five dogs each, threshold was measured at intervals of 60, 15, and 5 min. over periods of 8, 5, and 1 hr. respectively. Similar results were obtained …

Drug Induced Changes In Ventricular Defibrillation Threshold, Charles F. Babbs

Open Access Dissertations

No abstract provided.

Runoff And Erosion Characteristics Of Surface-Mined Sites In Western North Dakota, John E. Gilley, G. W. Gee, A. Bauer, W. O. Willis, R. A. Young

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to measure runoff and erosion from rangeland, spoil and topsoil sites. Measured soil losses were greatest on bare topsoil plots and least on the non-cultivated rangeland site. Application of a straw mulch reduced erosion on topsoil by over 90 percent. However, the meausred erosion and runoff values from the mulched topsoil sites were still over 50 percent higher than from the rangeland site.