Acute unilateral nephrectomy (AUN) increases electrolyte excretion by the remaining kidney and is associated with a decrease in cardiac output (CO). We studied anesthetized dogs to determine the role of the vagus nerves in these responses to AUN. In six intact animals, AUN increased sodium excretion (U Na V) from 31.7 ± 13.9 to 47.5 ± 14.3 /iEq/min (P < 0.05) and potassium excretion (U K V) from 29.3 ± 5.2 to 62.0 ± 11.4 /iEq/min (P < 0.02) as CO fell from 2.8 ± 0.2 to 1.9 to 0.3 liters/min (P < 0.005), and blood pressure and total peripheral resistance increased; no change in glomerular filtration rate (GFR) occurred, but renal blood flow fell significantly. In seven dogs undergoing sham nephrectomy, no signficant changes in any of these variables occurred. In 12 dogs with bilateral cervical vagotomy, AUN increased U N «V from 19.3 ± 5.3 to 39.6 ± 13.7 /lEq/min (P< 0.05) and U K V from 35.7 ± 5.5 to 46.8 ± 5.8 /iEq/min, (P < 0.001), without changes in GFR, renal blood flow, or mean arterial pressure. However, CO and total peripheral resistance did not change in this group. In nine dogs given intravenous atropine sulfate (0.067 mg/kg), AUN again resulted in comparable increases in cation excretion, but no significant change in CO occurred. These studies demonstrate that the increased electrolyte excretion seen after AUN is not prevented by bilateral cervical vagotomy or by atropine administration. However, the decrease in CO associated with AUN does not occur under these circumstances, indicating that reflex vagal efferent activity is responsible for this hemodynamic change. Therefore, the increase in electrolyte excretion after AUN can be dissociated from the decrease in CO.
Objective: To test the instructional effectiveness of simultaneous coupling of the spatial detection, discrimination and classification of simulated lung sounds to real‐time viewpoint tracking of displayed digital 3D anatomical models over the current method of auscultation alone. Methods: An integration of a computer‐based clinical training system comprising two complementary functions: 3D anatomical visualizations, and physiological diagnostic sounds simulation using a physical manikin. These functions are linked in real‐time by the student stethoscope's 3D position/orientation in space on the surface of the manikin. Thus, during any given simulation drill using as input a pre‐defined diagnostic lung sound, a student will sample signs from the manikin and simultaneously view the case's prescribed condition or pathology volumetrically reconstructed and visualized from de‐identified patient MRI/CT image sets carefully selected to represent the given abnormality. Expected results: Active student tracking, perception of diagnostic sounds and visualizations of the corresponding anatomical structures will significantly increase student learning over methods using auscultation without visualization.This research is supported by the Department of Anatomy and the Dean's Office, Des Moines University.
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