Anna Giuliani

Cardiac surgery-associated acute kidney injury.

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common and serious postoperative complication of cardiac surgery requiring cardiopulmonary bypass (CPB), and it is the second most common cause of AKI in the intensive care unit. Although the complication has been associated with the use of CPB, the etiology is likely multifactorial and related to intraoperative and early postoperative management including pharmacologic therapy. To date, very little evidence from randomized trials supporting specific interventions to protect from or prevent AKI in broad cardiac surgery populations has been found. The definition of AKI employed by investigators influences not only the incidence of CSA-AKI, but also the identification of risk variables. The advent of novel biomarkers of kidney injury has the potential to facilitate the subclinical diagnosis of CSA-AKI, the assessment of its severity and prognosis, and the early institution of interventions to prevent or reduce kidney damage. Further studies are needed to determine how to optimize cardiac surgical procedures, CPB parameters, and intraoperative and early postoperative blood pressure and renal blood flow to reduce the risk of CSA-AKI. No pharmacologic strategy has demonstrated clear efficacy in the prevention of CSA-AKI; however, some agents, such as the natriuretic peptide nesiritide and the dopamine agonist fenoldopam, have shown promising results in renoprotection. It remains unclear whether CSA-AKI patients can benefit from the early institution of such pharmacologic agents or the early initiation of renal replacement therapy.

Fluid Management in the Intensive Care Unit: Bioelectrical Impedance Vector Analysis as a Tool to Assess Hydration Status and Optimal Fluid Balance in Critically Ill Patients

Background: Fluid balance disorders are a relevant risk factor for morbidity and mortality in critically ill patients. Volume assessment in the intensive care unit (ICU) is thus of great importance, but there are currently few methods to obtain an accurate and timely assessment of hydration status. Our aim was to evaluate the hydration status of ICU patients via bioelectric impedance vector analysis (BIVA) and to investigate the relationship between hydration and mortality. Methods: We evaluated 280 BIVA measurements of 64 patients performed daily in the 5 days following their ICU admission. The observation period ranged from a minimum of 72 h up to a maximum of 120 h. We observed the evolution of the hydration status during the ICU stay in this population, and analyzed the relationship between mean and maximum hydration reached and mortality - both in the ICU and at 60 days - using logistic regression. Results: A state of overhydration was observed in the majority of patients (70%) on admission, which persisted during the ICU stay. Patients who required continuous renal replacement therapy (CRRT) were more likely to be overhydrated starting from the 2nd day of observation. Logistic regression showed a strong and significant correlation between mean/maximum hydration reached and mortality, both independently and correcting for severity of prognosis. Conclusions: Fluid overload measured by BIVA is a frequent condition in critically ill patients - whether or not they undergo CRRT - and a significant predictor of mortality. Hence, hydration status should be considered as an additional prognosticator in the clinical management of the critically ill patient. Key Messages: (i) On the day of ICU admittance, patients showed a marked tendency to overhydration (>70% of total). This tendency was more pronounced in patients on CRRT. (ii) Hyperhydration persisted during the ICU stay. Patients who underwent CRRT showed significantly higher hyperhydration from the 2nd day of hospitalization. (iii) Nonsurvivors showed worse hyperhydration patterns in comparison to survivors in logistic univariate analysis (p < 0.05). This relationship between hydration and mortality is confirmed even when controlling for the effect of a worse prognosis approximated by any of three ICU scoring systems (APACHE II, SAPS II and SOFA). Mean and maximum hydration levels present a stronger correlation with mortality than with mean and maximum cumulative fluid balance reached during the observation period.

The hemoglobin of amphibia. X. Sedimentation behaviour of frog, triton and axolotl hemoglobins.

Abstract 1. 1. Axolotl mexicanum hemoglobin: the oxygenated derivative remains as a tetramer as a function of pH, while part of the deoxygenated derivative undergoes a concentration-dependent polymerization to octomers below pH 6. 2. 2. Rana esculenta hemoglobin: the oxygenated derivative does not polymerize as a function of pH. The deoxygenated derivative partly polymerizes to octomers over the pH range 5–8. 3. 3. The polymerization of the deoxygenated Rana esculenta and Axolotl hemoglobin is reversible on reoxygenation of the solutions. 4. 4. Triturus cristatus hemoglobin: both the oxygenated and deoxygenated derivatives remain as tetrames over the pH range 5–8.

A monoclonal antibody monitoring band 3 modifications in human red blood cells.

Morphologic and methabolic erythrocyte modifications are thought to be the basis of cell removal from circulating blood. A significant role has been ascribed to the immunological network which may remove aged or misshapen erythrocytes through the binding of specific autoantibodies. Along this line recent observations indicate that a senescence antigen appears in consequence of postsynthetic modifications of band 3, one of the most important erythrocyte membrane proteins, which accounts for many functional activities of the red cells. On this basis, we raised a mouse hybridoma anti-band 3 monoclonal antibody (B6 MoAb) of the IgG2a class which monitors band 3 differences among normal red blood cells separated by Percoll density gradient. These differences are outlined by the decrease of B6 MoAb binding to band 3 monomer, the appearance of an 80–90 kDa new band, lighter than band 3, and the increase of low molecular weight fragments in the 4.5 region. The B6 MoAb appears to be very useful in detecting modifications of band 3 since it bind to a 19 kDa Chy-Try fragment estimated to be sensitive to aging.

Creation of autogenous radial cephalic direct wrist access for hemodialysis in the elderly using microsurgery

Purpose Guidelines recommend autogenous radial-cephalic AV fistula (RCAVF) as the first choice for hemodialysis. Concern has been raised that this is not suitable in the elderly. We assessed the results of microsurgery for RCAVF creation comparatively in patients older and younger than 70 years. Methods We prospectively followed 126 patients for three years. After systematic clinical and ultrasound assessment, a RCAVF was created using a surgical microscope. Patency was assessed immediately, at one week, one month and one year. Outcomes were recorded and stratified into two groups: <70y and >70y. Results RCAVF was created in 75.4% and 70.8% of the <70y and >70y groups, respectively. Incidence of early failure was 11% (<70y) and 13% (>70y). Primary and secondary patency at one year was 67% and 84% (<70y) versus 63% and 80% (>70y). Conclusions Microsurgery enabled the creation of RCAVF in >70y with acceptable risk of failure and slight differences by comparison with <70y. Older age should not preclude RCAVF creation.

Effect of Percutaneous Ventricular Assist Devices on Renal Function

Ventricular assist devices (VADs) are used to improve the systemic circulation and to decrease ventricular loading in patients with hemodynamic instability that is refractory to pharmacologic therapies. During an acute critical event, percutaneous devices are preferred because of their rapid deployment, since implantable devices require more extensive procedures. Implantable devices are used for patients with established end-stage heart failure as a bridge to heart transplantation, recovery or destination therapy. This report reviews mechanical principles and clinical studies regarding percutaneous VAD to address their potential renal effects. Since the focus of this study is set on devices that are dedicated to cardiac support only, extracorporeal membrane oxygenation systems are not included.

Peritoneal Dialysis for Patients with Autosomal Dominant Polycystic Kidney Disease

End-stage renal disease secondary to autosomal dominant polycystic kidney (ADPKD) is a common issue worldwide. Peritoneal dialysis (PD) is a reasonable option for renal replacement therapy for these patients and should not be withheld due to concerns that the patient may not tolerate the fluid volumes in the peritoneal cavity. This review covers the existing data on the outcomes and complications associated with the use of PD in the polycystic kidney disease patient. In general, PD is well tolerated and outcomes in ADPKD patients are equivalent to or better than other patient groups.

Worldwide Experiences with Assisted Peritoneal Dialysis

End-stage renal disease (ESRD) is common in the elderly population, and renal replacement therapy (RRT) is often required. However, in this particular subgroup of patients, the choice between hemodialysis (HD) and peritoneal dialysis (PD) is often not an easy decision to make. Published literature has adequately demonstrated that PD prevalence is significantly less than HD across all patient age groups despite several advantages. We also know that elderly patients are less likely to complete a PD assessment, due to both medical and social barriers. Additionally, elderly patients are often reluctant to go ahead with PD despite being eligible PD candidates, mainly due to the fear of performing self-therapy. Recently, many new assisted PD (asPD) programs have cropped up in several countries. The main aim of these programs is to overcome barriers to PD and to promote PD utilization among elderly and non-self-sufficient patients. Although asPD has proven to be associated with good clinical results, there still remain concerns about its greater use. In this review, we will first describe an ideal asPD model and then enumerate examples of strategies and outcomes associated with successful asPD programs worldwide.

The Influence of Glucose Exposure Load and Peritoneal Membrane Transport on Body Composition and Nutritional Status Changes after 1 Year on Peritoneal Dialysis

Background: The characteristics of peritoneal membrane transport differ among patients, affecting the prescription of peritoneal dialysis (PD) modality and glucose exposure in order to achieve an effective dialysis. This study aims to verify the influence of glucose exposure load and peritoneal membrane transport on body composition and nutritional status changes after the first year of PD. Methods: We examined a cohort of 85 incident PD patients during the first year of treatment. We established a cut-off of 5% to define changes in dry weight (DW), lean tissue mass (LTM), and fat mass (FM). Results: In total, 50.6% of the patients presented DW gain, 41.2% showed LTM loss, and 65.9% presented FM gain. Over the time (T0 – T12), we found significant differences in DW, body mass index (BMI), adipose tissue mass (ATM), FM and fat tissue index (FTI). Patients with lower dialysate-to-plasma creatinine ratio showed DW and FM gain. We observed a higher percentage of nonfast transporters in DW gain when comparing with DW no gain. As for glucose exposure load, no body composition changes were seen. Conclusions: Most patients presented DW gain, FM gain, and LTM loss. The characteristics of peritoneal membrane transport affected DW during the first year, changes being greater in nonfast than in fast transporters.

Cross-Over Efficiency Comparison of Different Tidal Automated Peritoneal Dialysis Schedules

This study compares 5 different tidal automated peritoneal dialysis (APD) prescriptions. Six low-average and 6 high-average transporters performed 3 separate sessions with 5 different schedules: (A) 50% tidal with initial fill volume (FV) 2 liters, (B) 50% tidal with 2.2 liters initial FV, (C) 2.2 liters initial FV with 70% tidal, (D) as in B, with one complete renewal of the initial FV at midsession, (E) 2.2 liters FV with breakpoint modality. Urea, creatinine and phosphate peritoneal clearances, sodium removal and ultrafiltration (UF) were compared using analysis of variance. Compared to treatment A, all the tested alternative schedules were associated with 10% significantly higher urea clearance; B, D and E, but not C, were associated with 10% higher creatinine clearance. Phosphate clearance was significantly higher with D, while sodium removal was larger with both C and D. UF was lower with A and E in high average transporters. Manipulation of the main prescriptive parameters of tidal APD has significant impact on its efficiency.