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Articles 1 - 4 of 4
Full-Text Articles in Engineering
Effect Of Pentobarbital Anesthesia On Ventricular Defibrillation Threshold In Dogs, Charles F. Babbs
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 …
Temporal Stability And Precision Of Ventricular Defibrillation Threshold Data, Charles F. Babbs, S J. Whistler, G Yim
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 …
Protection Of Ischemic Myocardium By Whole-Body Hypothermia After Coronary Artery Occlusion In Dogs, Dana R. Abendschein, Willis A. Tacker Jr, Charles F. Babbs
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
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 = …