Novel approach to monitoring renal perfusion with the use of continuous renal oximetery in the setting of aortic dissection

INTRODUCTION: Aortic dissections commonly extend beyond the renal arteries with varying effects ranging from asymptomatic to renal failure. We report a case of aortic dissection with initial renal compromise, which was continuously monitored utilizing direct renal oximetry for evaluation of real-time renal perfusion and function. CASE PRESENTATION: A 65 year-old female with a long history of uncontrolled hypertension presented with acute retrosternal chest pain radiating to the back for 12 hours. She was in stable condition except for a serum creatinine of 1.6mg/dl. Magnetic resonance angiography (MRA) demonstrated a type A dissection extending from the aortic root to the left common iliac artery. The only vessel originating from the false lumen was the left renal artery. The patient was emergently taken to the operating room for aortic root repair with graft. The patient sustained no intra-operative complications and underwent standard post-operative care. Due to initial elevation in serum creatinine and false lumen perfusion of the left kidney, FORE-SIGHT oximetry monitoring was placed on each kidney utilizing pre-operative imaging. Absolute renal tissue oxygen saturation was recorded for 3 consecutive days post-operatively. The right kidney spent a total 1858 minutes (89%) at greater than 60% saturation while the left kidney spent 1915 minutes (92%) (Figure 1). Neither kidney recorded saturations below 52% and serum creatinine cleared to baseline of 1.0 mg/dl. Computed tomography (CT) angiography confirmed perfusion in both kidneys. DISCUSSION: Distal organ perfusion can be a difficult assessment to make in the setting of aortic dissection. The laser technology utilized by FORE-SIGHT implements precise and narrow wavelengths proven to provide more accurate and absolute oxygen saturation values.1 By utilizing FORE-SIGHT oximetry in conjunction with imaging for precise placement, our group was able to accurately monitor renal perfusion in real time as opposed to waiting for contrast CT scan or traditional secondary markers such as serum creatinine and urine output. Saturations were maintained at expected levels throughout the post-operative course and renal function improved. This novel approach may serve a role in adjusting for renal oxygenation and subsequent perfusion in order to prevent renal failure in variety of settings from aortic injury to open cardiac procedures. CONCLUSIONS: Renal oximetry may serve as an additional tool in evaluating, and potentially preventing, renal injury in the setting of aortic dissection

Understanding Transient Ionic Diode Currents and Impedance Responses for Aquivion® Coated Microholes

Ionic diode based devices or circuits can be applied, for example, in electroosmotic pumps or in desalination processes. Aquivion ionomer coated asymmetrically over a Teflon film (5 μm thickness) with a laser-drilled microhole (approximately 10 μm diameter) gives a cationic diode with a rectification ratio of typically 10-20 (measured in 0.01 M NaCl with ±0.3 V applied bias). Steady state voltammetry, chronoamperometry, and electrochemical impedance spectroscopy data are employed to characterize the ionic diode performance parameters. Next, a COMSOL 6.0 finite element model is employed to quantitatively assess/compare transient phenomena and to extract mechanistic information by comparison with experimental data. The experimental diode time constant and diode switching process associated with a distorted semicircle (with a typical diode switching frequency of 10 Hz) in the Nyquist plot are reproduced by computer simulation and rationalized in terms of microhole diffusion-migration times. Fundamental understanding and modeling of the ionic diode switching process can be exploited in the rational/optimized design of new improved devices.</p

Extracorporeal Membranous Oxygenation Mimics Aortic Dissection on CAT Scan.

A 66 year-old female presented with refractory acute congestive heart failure, cardiogenic shock, and ventricular tachyarrhythmia. Veno-arterial extracorporeal membrane oxygenation (ECMO) was placed via femoral cannulation for salvage and stabilized. CAT scan of the chest performed as a part of heart transplant work-up, demonstrated an unequal distribution of intravenous contrast in the aortic arch (Figure 1). Radiologist’s preliminary reading was of “aortic dissection” while in fact this is truly “normal ECMO flow”

Pulmonary Nontuberculous Mycobacterial Infections in the State of Para, an Endemic Region for Tuberculosis in North of Brazil

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil / Federal University of Para. Tropical Medicine Nucleus. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Federal University of Para. Tropical Medicine Nucleus. Belém, PA, Brazil.Oswaldo Cruz Institute. Oswaldo Cruz Foundation. Rio de Janeiro, RJ, Brazil.Federal University of Para. Department of Integrative Medicine. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil

Spin versus Lattice Polaron: Prediction for Electron-Doped CaMnO3

CaMnO3 is a simple bi-partite antiferromagnet(AF) which can be continuously electron-doped up to LaMnO3. Electrons enter the doubly degenerate E_g subshell with spins aligned to the S=3/2 core of Mn^4+ (T_2g^3)$. We take the Hubbard and Hund energies to be effectively infinite. Our model Hamiltonian has two E_g orbitals per Mn atom, nearest neighbor hopping, nearest neighbor exchange coupling of the S=3/2 cores, and electron-phonon coupling of Mn orbitals to adjacent oxygen atoms. We solve this model for light doping. Electrons are confined in local ferromagnetic (FM) regions (spin polarons) where there proceeds an interesting competition between spin polarization (spin polarons) which enlarges the polaron, and lattice polarization (Jahn-Teller polarons) which makes it smaller. A symmetric 7-atom ferromagnetic cluster (Mn_7^27+) is the stable result, with net spin S=2 relative to the undoped AF. The distorted oxygen positions around the electron are predicted. The model also predicts a critical doping x_c=0.045 where the polaronic insulator becomes unstable relative to a FM metal.Comment: 9 pages with 7 embedded postscript figures and 2 table

Mean arterial blood pressure : potential predictive tool for preeclampsia in a cohort of healthy nulliparous pregnant women

Background: Prediction of preeclampsia is a challenge to overcome. The vast majority of prospective studies in large general obstetric populations have failed in the purpose of obtain a useful and effective model of prediction, sometimes based on complex tools unavaible in areas where the incidence of preeclampsia is the highest. The goal of this study was to assess mean arterial blood pressure (MAP) levels at 19–21, 27–29 and 37–39 weeks of gestation and performance of screening by MAP for the prediction of preeclampsia in a Brazilian cohort of healthy nulliparous pregnant women. Methods: This was a cohort approach to a secondary analysis of the Preterm SAMBA study. Mean arterial blood pressure was evaluated at three different time periods during pregnancy. Groups with early-onset preeclampsia, late-onset preeclampsia and normotension were compared. Increments in mean arterial blood pressure between 20 and 27 weeks and 20 and 37 weeks of gestation were also calculated for the three groups studied. The accuracy of mean arterial blood pressure in the prediction of preeclampsia was determined by ROC curves. Results: Of the 1373 participants enrolled, complete data were available for 1165. The incidence of preeclampsia was 7.5%. Women with early-onset preeclampsia had higher mean arterial blood pressure levels at 20 weeks of gestation, compared to the normotensive group. Women with late-onset preeclampsia had higher mean arterial blood pressure levels at 37 weeks of gestation, than the normotensive groups and higher increases in this marker between 20 and 37 weeks of gestation. Based on ROC curves, the predictive performance of mean arterial blood pressure was higher at 37 weeks of gestation, with an area under the curve of 0.771. Conclusion: As an isolated marker for the prediction of preeclampsia, the performance of mean arterial blood pressure was low in a healthy nulliparous pregnant women group. Considering that early-onset preeclampsia cases had higher mean arterial blood pressure levels at 20 weeks of gestation, future studies with larger cohorts that combine multiple markers are needed for the development of a preeclampsia prediction model

Incidence and risk factors for preeclampsia in a cohort of healthy nulliparous pregnant women : a nested case-control study

The objective of this study is to determine the incidence, socio-demographic and clinical risk factors for preeclampsia and associated maternal and perinatal adverse outcomes. This is a nested case-control derived from the multicentre cohort study Preterm SAMBA, in fve diferent centres in Brazil, with nulliparous healthy pregnant women. Clinical data were prospectively collected, and risk factors were assessed comparatively between PE cases and controls using risk ratio (RR) (95% CI) plus multivariate analysis. Complete data were available for 1,165 participants. The incidence of preeclampsia was 7.5%. Body mass index determined at the frst medical visit and diastolic blood pressure over 75mmHg at 20 weeks of gestation were independently associated with the occurrence of preeclampsia. Women with preeclampsia sustained a higher incidence of adverse maternal outcomes, including C-section (3.5 fold), preterm birth below 34 weeks of gestation (3.9 fold) and hospital stay longer than 5 days (5.8 fold) than controls. They also had worse perinatal outcomes, including lower birthweight (a mean 379g lower), small for gestational age babies (RR 2.45 [1.52–3.95]), 5-minute Apgar score less than 7 (RR 2.11 [1.03–4.29]), NICU admission (RR 3.34 [1.61–6.9]) and Neonatal Near Miss (3.65 [1.78–7.49]). Weight gain rate per week, obesity and diastolic blood pressure equal to or higher than 75mmHg at 20 weeks of gestation were shown to be associated with preeclampsia. Preeclampsia also led to a higher number of C-sections and prolonged hospital admission, in addition to worse neonatal outcomes