Aiming at the current situation of performance testing of hemodialysis extracorporeal circulation tubing, which has slow efficiency, inaccurate measurement, and inconvenient testing, a portable detection system for testing the performance of hemodialysis extracorporeal circulation tubing is designed. The system mainly includes a hardware system and a software system. The hardware system uses STM32F407 single-chip microcomputer as the core to design the driving control of the roller pump; the software system uses the C++ real-time operating system, and the flow detection data is transmitted to the upper computer through RS485 communication and displayed. Experimental showed that the system detects the accuracy and the stability of the flow rate. It has the characteristics of stability and high precision. The relative error of the experimental measurement is within the range of ±10%. The weight of the whole machine is 2 kg, which improves the efficiency by 50% compared with the traditional detection method.
Computers ; Equipment Design ; Extracorporeal Circulation ; Microcomputers ; Renal Dialysis ; Software

Concurrent involvement of bilateral renal and cerebral arteries, usually incurred as stenosis, is rare in childhood-onset Takayasu arteritis (c-TA). We report the case of a 14-year-old girl, with c-TA, presenting with transient ischemic attack after endovascular revascularization for renal artery stenosis and cerebrovascular stroke after surgical revascularization for cerebral artery stenosis associated with childhood-onset moyamoya syndrome. We deem that decrease of blood pressure by endovascular revascularization and improvement of cerebral perfusion by surgical revascularization may have jeopardized the cerebral deep watershed zone to cerebral ischemia followed by cerebral hyperperfusion syndrome and caused transient ischemic attack and cerebrovascular stroke in our patient. Revascularization could be a double-edge sword for c-TA patients presenting with concomitant renal artery stenosis and cerebral artery stenosis, and should be performed with caution. Quantitative analysis of cerebral blood flow by brain magnetic resonance imaging and angiography should be performed within 48 hours after surgical revascularization in c-TA.
Adolescent* ; Angiography ; Blood Pressure ; Brain ; Brain Ischemia ; Cerebral Arteries* ; Cerebrovascular Circulation ; Constriction, Pathologic* ; Female* ; Humans ; Hypertension, Renovascular ; Ischemic Attack, Transient ; Magnetic Resonance Imaging ; Moyamoya Disease* ; Perfusion ; Renal Artery Obstruction ; Stroke ; Takayasu Arteritis*

Angiography ; Arteriovenous Shunt, Surgical ; Brachiocephalic Veins ; diagnostic imaging ; Collateral Circulation ; Constriction, Pathologic ; diagnostic imaging ; Female ; Humans ; Jugular Veins ; diagnostic imaging ; Kidney Failure, Chronic ; therapy ; Male ; Middle Aged ; Phlebography ; Renal Dialysis ; methods ; Subclavian Vein ; diagnostic imaging ; Vascular Access Devices

Arginine vasopressin (AVP), also known as antidiuretic hormone, is a peptide endogenously secreted by the posterior pituitary in response to hyperosmolar plasma or systemic hypoperfusion states. When administered intravenously, it causes an intense peripheral vasoconstriction through stimulation of V₁ receptors on the vascular smooth muscle. Patients in refractory shock associated with severe sepsis, cardiogenic or vasodilatory shock, or cardiopulmonary bypass have inappropriately low plasma levels of AVP (‘relative vasopressin deficiency’) and supersensitivity to exogenously-administered AVP. Low doses of AVP and its synthetic analog terlipressin can restore vasomotor tone in conditions that are resistant to catecholamines, with preservation of renal blood flow and urine output. They are also useful in the treatment of refractory arterial hypotension in patients chronically treated with renin-angiotensin system inhibitors, cardiac arrest, or bleeding esophageal varices. In the perioperative setting, they represent attractive adjunct vasopressors in advanced shock states that are unresponsive to conventional therapeutic strategies.
Arginine Vasopressin ; Cardiopulmonary Bypass ; Catecholamines ; Esophageal and Gastric Varices ; Heart Arrest ; Hemorrhage ; Humans ; Hypotension ; Muscle, Smooth, Vascular ; Plasma ; Renal Circulation ; Renin-Angiotensin System ; Sepsis ; Shock ; Shock, Hemorrhagic ; Shock, Septic ; Vasoconstriction ; Vasopressins*

We report a rare case of bilateral renal infarction resulting in acute renal failure in a previously healthy 26-year-old soldier. The patient presented with an abdominal pain and bilateral costovertebral angle tenderness. Laboratory studies showed elevated serum creatinine, mild leukocytosis, and increased lactate dehydrogenase. Contrast-enhanced computed tomography showed multiple perfusion defects in both kidneys with wedge-shaped infarction in right kidney. Kidney biopsy performed in the left kidney revealed microinfarction. Comprehensive work-up did not reveal any specific causes or risk factors except smoking, and the infarction was considered to be idiopathic. He emphasized that he received extremely strenuous military training several days before he came to the hospital. He was treated with low molecular weight heparin with significant improvement in renal function. Further studies are needed for the characterization of idiopathic renal infarction in previously healthy individuals and evaluating the mechanisms including strenuous physical activity on the renal blood flow.
Abdominal Pain ; Acute Kidney Injury ; Adult ; Biopsy ; Creatinine ; Heparin, Low-Molecular-Weight ; Humans ; Infarction* ; Kidney ; L-Lactate Dehydrogenase ; Leukocytosis ; Male* ; Military Personnel ; Motor Activity ; Perfusion ; Renal Circulation ; Risk Factors ; Smoke ; Smoking

Methanol poisoning is a medical emergency that requires rapid elimination of the toxin and its metabolites for recovery. The danger of methanol results from the accumulation of its toxic metabolite formic acid. This accumulation may result in the development of metabolic acidosis, visual impairment, and damage to the basal ganglia. Extracorporeal treatment is recommended in severe cases of methanol poisoning with coma, seizure, new vision deficits, metabolic acidosis, high serum anion gap, elevated methanol concentrations or impaired kidney function. Although the serum methanol concentration is helpful in determining the use of extracorporeal treatment, methanol assays are not standard laboratory tests in Korea. Herein, we report a case of methanol poisoning in which the patient's clinical improvement was confirmed using serum and urine methanol levels.
Acid-Base Equilibrium ; Acidosis ; Basal Ganglia ; Coma ; Emergencies ; Extracorporeal Circulation ; Kidney ; Korea ; Methanol* ; Osmolar Concentration ; Poisoning* ; Renal Replacement Therapy* ; Seizures ; Vision Disorders

Scrub typhus, caused by Orientia tsutsugamushi, is an acute febrile illness. Characteristics of tsutsugamushi disease are fever, rash and eschar. However, severe complications might rarely occur, such as acute fulminant myocarditis caused by scrub typhus. Thus, there are few reports of recovery from seriously complicated cases. We report on an adult male with scrub typhus complicated with acute fulminant myocarditis with no previous comorbid illness who recovered successfully with proper treatment including antibiotics, ventilator support, percutaneous cardiopulmonary support, and continuous renal replacement therapy.
Adult ; Anti-Bacterial Agents ; Exanthema ; Extracorporeal Circulation ; Fever ; Humans ; Male ; Myocarditis* ; Orientia tsutsugamushi ; Renal Replacement Therapy ; Scrub Typhus* ; Ventilators, Mechanical

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.
Aged ; Carotid Arteries/diagnostic imaging ; Cerebrovascular Circulation/*physiology ; Dizziness/etiology ; Female ; Hemodynamics/*physiology ; Humans ; Kidney Failure, Chronic/*physiopathology ; Male ; Middle Aged ; Renal Dialysis ; Risk Factors ; Ultrasonography, Doppler, Duplex

In this study, we characterized cerebral blood flow changes by assessment of blood flow parameters in neck arteries using carotid duplex ultrasonography and predictive factors for these hemodynamic changes. Hemodynamic variables were measured before and during hemodialysis in 81 patients with an arteriovenous access in their arm. Hemodialysis produced significant lowering in peak systolic velocity and flow volume of neck arteries and calculated total cerebral blood flow (1,221.9 ± 344.9 [before hemodialysis] vs. 1,085.8 ± 319.2 [during hemodialysis], P < 0.001). Effects were greater in vessels on the same side as the arteriovenous access and these changes were influenced by arteriovenous access flow during hemodialysis, both in the CCA (r = -0.277, P = 0.015) and the VA (r = -0.239, P = 0.034). The change of total cerebral blood flow during hemodialysis was independently related with age, presence of diabetes, and systemic blood pressure.
Aged ; Carotid Arteries/diagnostic imaging ; Cerebrovascular Circulation/*physiology ; Dizziness/etiology ; Female ; Hemodynamics/*physiology ; Humans ; Kidney Failure, Chronic/*physiopathology ; Male ; Middle Aged ; Renal Dialysis ; Risk Factors ; Ultrasonography, Doppler, Duplex

PURPOSE: The goal of this study was to evaluate the effect of vascular compliance, resistance, and pulse rate on the resistive index (RI) by using an electrical circuit model to simulate renal blood flow. METHODS: In order to analyze the renal arterial Doppler waveform, we modeled the renal blood-flow circuit with an equivalent simple electrical circuit containing resistance, inductance, and capacitance. The relationships among the impedance, resistance, and compliance of the circuit were derived from well-known equations, including Kirchhoff's current law for alternating current circuits. Simulated velocity-time profiles for pulsatile flow were generated using Mathematica (Wolfram Research) and the influence of resistance, compliance, and pulse rate on waveforms and the RI was evaluated. RESULTS: Resistance and compliance were found to alter the waveforms independently. The impedance of the circuit increased with increasing proximal compliance, proximal resistance, and distal resistance. The impedance decreased with increasing distal compliance. The RI of the circuit decreased with increasing proximal compliance and resistance. The RI increased with increasing distal compliance and resistance. No positive correlation between impedance and the RI was found. Pulse rate was found to be an extrinsic factor that also influenced the RI. CONCLUSION: This simulation study using an electrical circuit model led to a better understanding of the renal arterial Doppler waveform and the RI, which may be useful for interpreting Doppler findings in various clinical settings.
Compliance ; Computer Simulation ; Electric Impedance ; Heart Rate ; Jurisprudence ; Pulsatile Flow ; Renal Artery ; Renal Circulation ; Ultrasonography, Doppler