Urine volume as a predicting factor for furosemide clearance during continuous infusion in AKI septic shock patients on hemodiafiltration.

BACKGROUND: This study assessed the contribution of intracorporeal (IC) and extracorporeal clearance (EC) of furosemide in patients with septic acute kidney injury (AKI), and the relationship between plasma concentrations and urine volume. METHODS: Prospective cohort observational study of 15 patients with septic AKI undergoing continuous veno-venous hemodiafiltration (CVVHDF) divided according to urine volume (< 500 ml/12 h, Oliguria group, n = 5; > 500 ml/12 h, Diuresis group, n = 10) during continuous infusion of furosemide (120 mg/12 h) at steady-state condition. Plasma and effluent furosemide concentrations were determined by high-performance liquid chromatography (HPLC)-mass spectrometry every 12 h for 48 h. RESULTS: Furosemide plasma concentrations and total body clearance (TBC) were 6.14 mg/l and 22.1 ml/min for the Oliguria group, and 2.63 mg/l and 54.4 ml/min for the Diuresis group, respectively (p < 0.05). When urine volume was < 500 ml/24 h, the furosemide plasma concentrations peaked at the potentially toxic value of 13.0 mg/l. Furosemide EC was not relevant for the Diuresis group, but it represented 18% of TBC for the Oliguria group. Furosemide plasma concentrations correlated positively with dose infusion for both groups (r = 0.728 and 0.685, p < 0.05), and negatively with urine volume only for the Diuresis (r = - 0.578, p < 0.01) but not for the Oliguria group (r = - 0.089, p = 0.715). CONCLUSIONS: For patients with urine volume > 500 ml/12 h continuous infusion of furosemide up to 480 mg/24 h leads to increasing urine volume, which can predict furosemide plasma levels within its safety range. When the urine volume is lower, the furosemide plasma levels are increased beyond any further diuretic efficacy.

RIPK3 promotes sepsis-induced acute kidney injury via mitochondrial dysfunction.

Sepsis causes acute kidney injury (AKI) in critically ill patients, although the pathophysiology remains unclear. The receptor-interacting protein kinase-3 (RIPK3), a cardinal regulator of necroptosis, has recently been implicated in the pathogenesis of human disease. In mice subjected to polymicrobial sepsis, we demonstrate that RIPK3 promotes sepsis-induced AKI. Utilizing genetic deletion and biochemical approaches in vitro and in vivo, we identify a potentially novel pathway by which RIPK3 aggravates kidney tubular injury independently of the classical mixed lineage kinase domain-like protein-dependent (MLKL-dependent) necroptosis pathway. In kidney tubular epithelial cells, we show that RIPK3 promotes oxidative stress and mitochondrial dysfunction involving upregulation of NADPH oxidase-4 (NOX4) and inhibition of mitochondrial complex I and -III, and that RIPK3 and NOX4 are critical for kidney tubular injury in vivo. Furthermore, we demonstrate that RIPK3 is required for increased mitochondrial translocation of NOX4 in response to proinflammatory stimuli, by a mechanism involving protein-protein interactions. Finally, we observed elevated urinary and plasma RIPK3 levels in human patients with sepsis-induced AKI, representing potential markers of this condition. In conclusion, we identify a pathway by which RIPK3 promotes kidney tubular injury via mitochondrial dysfunction, independently of MLKL, which may represent a promising therapeutic target in sepsis-induced AKI.

Predictors for uroseptic shock in patients who undergo minimally invasive percutaneous nephrolithotomy.

To identify risk factors that can predict which patient is likely to progress from systemic inflammatory response syndrome (SIRS) to uroseptic shock after minimally invasive percutaneous nephrolithotomy (MPCNL) for the upper urinary tract stones. We retrospectively reviewed 156 patients who suffered infectious complications after MPCNL from March 2014 to February 2016. Perioperative risk factors that could potentially contribute to uroseptic shock were compared to those of patients with only SIRS. 135 of the 156 patients developed to SIRS only, the remaining 21 patients progressed to uroseptic shock. The rate of positive preoperative urine nitrite was significantly higher (p < 0.001), stone diameter was larger (p = 0.015) and operative time was longer (p < 0.001) in uroseptic shock group. Multivariable logistic analysis showed that preoperative urine nitrite (OR 10.570, p = 0.025), stone size (OR 11.512, p = 0.009) and postoperative blood leukopenia (OR 0.009, p < 0.001) were independently related to uroseptic shock. Moreover, ROC curve analysis showed that white blood count threshold within the first 3 h of uroseptic shock was 2.98 × 109/L. The sensitivity and specificity of leukocyte count in predicting uroseptic shock were 90.5 and 92.6%, respectively. Preoperative urine nitrite, stone size and postoperative leukocyte count are statistically linked to uroseptic shock after MPCNL. Leukopenia of less than 2.98 × 109/L within 3 h after MPCNL can be a predictor for uroseptic shock. For patients who have high risk factors for developing uroseptic shock, the white blood count should be measured within 3 h after MPCNL.

Relationship Between Alternative Resuscitation Strategies, Host Response and Injury Biomarkers, and Outcome in Septic Shock: Analysis of the Protocol-Based Care for Early Septic Shock Study.

OBJECTIVES: The Protocol-based Care for Early Septic Shock trial found no differences across alternative resuscitation strategies in all-cause mortality. A separate aim was to determine whether differences in resuscitation strategies affected trajectories of biomarkers of key pathways associated with downstream clinical outcomes of sepsis and whether there were differences in survival across treatment arms for patients with different baseline biomarker profiles. DESIGN: Secondary analysis of a large randomized clinical trial. SETTING: Thirty-one U.S. hospitals. PATIENTS: Six hundred twenty-eight patients with septic shock. INTERVENTIONS: Two resuscitation protocols versus usual care. MEASUREMENTS AND MAIN RESULTS: We measured a panel of biomarkers representing four pathophysiologic domains: "inflammation" (tumor necrosis factor, interleukin-6, and -10); "coagulation" (D-dimers, thrombin-antithrombin complex); "oxidative stress" (urine isoprostane); and "tissue hypoxia" (lactate) at 0, 6, 24, and 72 hours after treatment. We analyzed whether alternative resuscitation strategies affected biomarker trajectories over 72 hours and whether effects on 90-day hospital mortality varied by baseline (time 0) biomarker profiles-both using regression models with interaction terms for treatment arms. For all baseline biomarkers, higher concentrations were associated with increased risk of death by 90 days. However, there was no significant effect of treatment assignment on subsequent biomarker trajectories. We did find evidence for heterogeneity of treatment effect of protocol-based care on mortality for patients with different baseline [interleukin-6] and [interleukin-6] × [interleukin-10] profiles, whereas patients with the lowest quartiles fared better with protocol-based care (odds ratios, 0.32 [0.13-075]; p = 0.01 and 0.32 [0.14-0.73]; p = 0.01, respectively). CONCLUSIONS: In patients with septic shock, alterations in inflammation, coagulation, oxidative stress, and tissue hypoxia are common and associated with adverse outcomes but are not influenced by protocol-based resuscitation compared with usual care. However, contrary to expectation, protocol-based resuscitation appeared to be superior in patients with lower concentrations of inflammatory biomarkers. The mechanisms responsible for this effect are unclear.

Clinical Usefulness of Urinary Fatty Acid Binding Proteins in Assessing the Severity and Predicting Treatment Response of Pneumonia in Critically Ill Patients: A Cross-Sectional Study.

To investigate the clinical relevance of urinary fatty acid binding proteins (FABPs), including intestinal-FABP, adipocyte-FABP, liver-FABP, and heart-FABP in pneumonia patients required admission to respiratory intensive care unit (RICU).Consecutive pneumonia patients who admitted to RICU from September 2013 to October 2014 were enrolled except for those with pneumonia for more than 24 h before admission to RICU. Pneumonia patients were further divided into with and without septic shock subgroups. Twelve patients without infection were enrolled to serve as control group. Urine samples were collected on days 1 and 7 after admission to RICU for measuring FABPs and inflammatory cytokines. Clinical and laboratory data were collected and compared between pneumonia and control groups, and between the pneumonia patients with and without septic shock.There were no significant differences in urinary levels of various FABPs and inflammatory cytokines measured on day 1 between control and pneumonia groups. Urinary values of intestine-FABP (P = 0.020), adipocyte-FABP (P = 0.005), heart-FABP (P = 0.025), and interleukin-6 (P = 0.019) were significantly higher and arterial oxygen tension/fraction of inspired oxygen (PaO2/FiO2, P/F) ratio (P = 0.024) was significantly lower in pneumonia patients with septic shock on day 1 than in those without septic shock. After multivariate analysis, adipocyte-FABP was the independent factor (P = 0.026). Urinary levels of FABPs measured on day 7 of pneumonia patients were significantly lower in the improved than in nonimproved groups (P = 0.030 for intestine-FABP, P = 0.003 for adipocyte-FABP, P = 0.010 for heart-FABP, and P = 0.008 for liver-FABP, respectively). After multivariate analysis, adipocyte-FABP was the independent factor (P = 0.023).For pneumonia patients required admission to RICU, urinary levels of adipocyte-FABP on days 1 and 7 after admission to RICU may be valuable in assessing the pneumonia severity and in predicting treatment response, respectively. Further studies with larger populations are needed to verify these issues.

Randomized controlled trial of calcitriol in severe sepsis.

RATIONALE: Vitamin D and its metabolites have potent immunomodulatory effects in vitro, including up-regulation of cathelicidin, a critical antimicrobial protein. OBJECTIVES: We investigated whether administration of 1,25-dihydroxyvitamin D (calcitriol) to critically ill patients with sepsis would have beneficial effects on markers of innate immunity, inflammation, and kidney injury. METHODS: We performed a double-blind, randomized, placebo-controlled, physiologic study among 67 critically ill patients with severe sepsis or septic shock. Patients were randomized to receive a single dose of calcitriol (2 µg intravenously) versus placebo. The primary outcome was plasma cathelicidin protein levels assessed 24 hours after study drug administration. Secondary outcomes included leukocyte cathelicidin mRNA expression, plasma cytokine levels (IL-10, IL-6, tumor necrosis factor-α, IL-1ß, and IL-2), and urinary kidney injury markers. MEASUREMENTS AND MAIN RESULTS: Patients randomized to calcitriol (n = 36) versus placebo (n = 31) had similar plasma cathelicidin protein levels at 24 hours (P = 0.16). Calcitriol-treated patients had higher cathelicidin (P = 0.04) and IL-10 (P = 0.03) mRNA expression than placebo-treated patients 24 hours after study drug administration. Plasma cytokine levels (IL-10, IL-6, tumor necrosis factor-α, IL-1ß, and IL-2) and urinary kidney injury markers were similar in calcitriol- versus placebo-treated patients (P > 0.05 for all comparisons). Calcitriol had no effect on clinical outcomes nor were any adverse effects observed. CONCLUSIONS: Calcitriol administration did not increase plasma cathelicidin protein levels in critically ill patients with sepsis and had mixed effects on other immunomodulatory markers. Additional phase II trials investigating the dose and timing of calcitriol as a therapeutic agent in specific sepsis phenotypes may be warranted. Clinical trial registered with www.clinicaltrials.gov (NCT 01689441).

Sepsis-surviving mice are more susceptible to a secondary kidney insult.

OBJECTIVE: It is well known that sepsis causes damage in different organs, including kidneys. However, few studies have been conducted on the magnitude of the long-term effects of sepsis on the surviving population, in particular, in relation to kidney disease. In this study, we examined the impact of long-term effects of sepsis on a second kidney insult. DESIGN: Prospective experimental study. SETTING: University research laboratory. INTERVENTIONS: Wild-type mice were subjected to the cecal ligation and puncture sepsis model. Control animals underwent identical laparotomy but without ligation and cecum puncture. On days 0, 7, and 14 after surgery, the ratio between urinary protein and creatinine was measured. Fifteen days after surgery, surviving mice were subjected to a second kidney insult through intraperitoneal injections of bovine serum albumin for 7 days. On day 22 after surgery, urinary protein and creatinine, γ-glutamyl transpeptidase, lactate dehydrogenase, histologic parameters, macrophage infiltration, apoptotic cell, renal and plasmatic cytokines were determined. MEASUREMENTS AND MAIN RESULTS: On days 7 and 14 after surgery, the urinary protein and creatinine observed in the septic animal group were higher than those observed in the control group. On day 22 after surgery, sepsis-surviving animals that were subjected to a second kidney insult showed more severe tubular injury compared with controls. This process seems to involve an immunosuppressive state because the concentrations of some renal cytokines, such as tumor necrosis factor-α, interleukin 6, interferon-γ and chemokine ligand 2, were decreased and leukocyte numbers were increased. CONCLUSIONS: These results suggest that sepsis induces long-term effects in kidney structure aggravating tubule damage in a second kidney insult.

Urinary excretion of free cysteine in critically ill neonates.

UNLABELLED: In preliminary observations, significant amounts of free cysteine, a neurotoxic amino acid, were noted in the urine of asphyxiated or septic-shocked neonates. The present study was conducted to determine whether free urinary cysteine was elevated in these critically ill neonates compared with a control group, and to assess the clinical significance of this generation. Free cysteine was measured in the urine of newborn infants with perinatal asphyxia (n = 16) or neonatal sepsis (n = 14) and the urine of a control group (n = 10) by ion-exchange chromatography. Relationships between cysteine levels and the clinical severity, sulfite supply and neurological outcome of the patients were then studied. Urinary cysteine was 27.6 (15-49) mmol mol(-1) creatinine for the patients but was not detectable in the control group. Cysteine levels were correlated with the severity of neonatal septic shock but not with the grade of perinatal asphyxia and did not have a specific influence on the neurological outcome of these patients. The correlation between cysteine level and the severity of neonatal septic shock was indirect and probably linked to higher sulfite administration in this population. CONCLUSION: The mean daily supply of sulfites is high in critically ill neonates, mainly originating from dopamine and generating significant amounts of cysteine. Although a worsening effect attributable to cysteine on the neurological outcome of the patients could not be demonstrated, the appropriateness of cryptic administration of sulfites by way of drug excipients is called into question.

Urine hydrogen peroxide during adult respiratory distress syndrome in patients with and without sepsis.

BACKGROUND: The lung injury in adult respiratory distress syndrome (ARDS) has been associated with increased expiratory hydrogen peroxide (H2O2) concentrations. Furthermore, patients with sepsis and ARDS are reported to have greater serum scavenging of H2O2 than patients with ARDS only. We hypothesized that the systemic presence of H2O2 would be detectable in the urine of these two groups of patients and that, in the case of ARDS sepsis, the relative contribution of each disease to the production this analyte would be discernible. Accordingly, we used an in vitro radioisotope assay to follow the weekly course of urine H2O2 levels in ARDS patients with and without sepsis, and in samples from control non-ARDS patients with sepsis with indwelling urinary catheters and in samples provided by healthy volunteers. METHODS: Thirty patients with ARDS were included in the study: 23 had sepsis and 7 were sepsis free. An indwelling catheter was used to collect urine from each patient over a 24-h period, first within 48 h of ICU admission and then every seventh day over the course of their illness. Urine H2O2 was measured by competitive decarboxylation of 1-14C-alpha-ketoglutaric acid by H2O2. Urine samples were provided by 20 healthy volunteers while, in 10 non-ARDS patients with sepsis, urine was collected over one 24-h period following a 5-day minimum with an indwelling urinary catheter. RESULTS: Urine H2O2 concentration in healthy control subjects (88 +/- 4 mumol/L) and non-ARDS patients with urinary catheters (96 +/- 5 mumol/L) was not significantly different. During the first 48 h in the ICU, urine H2O2 in patients with ARDS only (295 +/- 29 mumol/L) was significantly lower (p < 0.05) than patients with ARDS and sepsis (380 +/- 13 mumol/L); however, the lung injury scores of these two groups did not differ. Furthermore, within the first 48 h, the urine H2O2 of the patients with ARDS and sepsis who did not survive (427 +/- 19 mumol/L; n = 7) was significantly higher than that in patients who survived sepsis (352 +/- 14 mumol/L; n = 15). Thereafter, the lung injury scores and urine H2O2 levels of the nonsurvivor ARDS-sepsis group remained significantly higher compared with the other two groups. At lung injury scores of 3 and 2, regardless of days in ICU, the patients with ARDS only had significantly lower urine H2O2 (266 +/- 30 mumol/L and 167 +/- 24 mumol/L, respectively) compared with the survivor ARDS-sepsis group (376 +/- 19 mumol/L and 250 +/- mumol/L). When the patients with ARDS (both ARDS only and with sepsis) recovered, their urine H2O2 concentration did not differ from the control groups (healthy donors and patients without ARDS). CONCLUSION: Lung injury scores did not differentiate patients with ARDS and sepsis from patients with ARDS only during the first 10 days in the ICU; however, urine H2O2 levels were significantly greater in the patients with ARDS and sepsis. Moreover, despite no initial difference in lung injury, patients who did not survive ARDS and sepsis had consistently greater urine H2O2 concentration than patients who survived sepsis. The urine H2O2 level in the ARDS-only group was about 70 percent of the level in the survivor ARDS and sepsis group, suggesting that ARDS alone is the major contributor to the H2O2 oxidant processes during combined ARDS and sepsis. Furthermore, these studies demonstrate that urine H2O2 may be a useful analyte to differentiate the severity of oxidant processes in patients with ARDS and sepsis albeit the prognosis appears to be survival or nonsurvival.

Effect of meningococcal endotoxin in a rabbit model of shock.

Endotoxin in the form of a lipooligosaccharide (LOS) plays a key role in the development of shock in meningococcal sepsis. To examine hemodynamic and biochemical alterations during meningococcal endotoxic shock, we established a rabbit model. Thirty-nine rabbits, weighing 2.5-4.4 kg, were studied. After anesthesia with intramuscular ketamine (20 mg/kg) and xylazine (4 mg/kg), femoral venous and arterial catheters were inserted. Control animals received only saline, while rabbits in each of four additional groups were given LOS in 10-fold increments from 0.1 microgram/kg to 100 microgram/kg. Mean arterial pressure (MAP), heart rate (HR), respirations (RR), temperature (T), urine output, and arterial blood gases (pH, PCO2, PO2, and bicarbonate) were determined at baseline and hourly. Endotoxin levels and TNF levels were measured at 30, 60, 120, 180, 240, 300, and 360 min post-LOS. Survival was recorded. One-way analysis of variance (ANOVA) and the Scheffe procedure, paired samples t-test, two-tailed t-test, and Fisher's exact test were used. Pearson's coefficients were calculated. Animals receiving meningococcal LOS developed tachycardia and compensated metabolic acidosis with an initially normal pH and MAP. With progression of the shock state, the pH decreased and hypotension ensued. Maximal levels of endotoxin were measured 30 min after LOS injection and declined during the ensuing 6 hr. TNF rose from undetectable to markedly elevated levels and peaked at 60-120 min post-LOS. Increasing the amount of injected endotoxin produced more profound degrees of shock until a dose of 10.0 micrograms/kg was reached. There was no correlation between serum TNF at 60 min and survival at 6 hr or 24 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumor necrosis factor and interleukin 1 appearance in experimental gram-negative septic shock. The effects of plasma exchange with albumin and plasma infusion.

To study the effect of plasma removal vs plasma administration on the appearance of tumor necrosis factor (TNF) and interleukin 1 in septic shock, 24 anesthetized piglets were inoculated with live Escherichia coli. Plasma exchange with albumin was performed in one group. Fresh-frozen plasma was administered to a second group. A third group served as nontreated controls. Following plasma exchange, a reduction in both TNF and interleukin 1 levels occurred, whereas plasma infusion was followed by a decrease in TNF levels only. No significant differences were observed between the two treated groups with respect to survival or cardiovascular performance, with both being significantly enhanced compared with the controls. High levels of TNF and interleukin 1 correlated with depressed cardiovascular performance in the early phase of the shock. Our results confirm the important role of TNF and interleukin 1 as early mediators of septic shock. However, the benefit of reducing cytokine activity in later stages of septicemia seems to be dubious.

The protective effect of thromboxane synthetase inhibition on renal function in systemic sepsis.

To study the role of thromboxane in systemic sepsis and renal failure, peritonitis was induced surgically in 22 sheep, leading to local and systemic sepsis. A selective thromboxane synthetase inhibitor, U63,557A (Upjohn Co, Kalamazoo, MI) was given before surgery in five animals and 30 minutes after surgery in five animals. A typical picture of volume-loaded, normotensive, vasodilated septic shock developed in all animals. Twenty four hours after induction of sepsis, the control group showed a marked reduction in glomerular filtration rate (GFR), urine volume, and urinary sodium excretion. Pretreated animals showed no change in GFR and a smaller reduction in urine volume and sodium excretion. The posttreatment group showed no change in any parameters of renal function. Plasma renin activity, urinary TXB2 excretion, and urinary 6-keto PGF1 alpha excretion increased after 24 hours only in the control group. Urinary TXB2 excretion was reduced by 80% in animals given U63,557A before surgery. The results indicate a significant protective effect of U63,557A on renal function during septic shock, probably related to reduced thromboxane synthesis, with no apparent deleterious systemic effects. The results support a role for thromboxane in the pathogenesis of acute renal failure in systemic sepsis.