Acute Kidney Injury in Extracorporeal Membrane Oxygenation Patients: National Analysis of Impact of Age.

BACKGROUND: The aim of this study was to determine epidemiology and outcomes of acute kidney injury (AKI) in patients on extracorporeal membrane oxygenation (ECMO) and to assess if age modifies the effect of AKI on mortality. METHODS: Using National (Nationwide) Inpatient Sample Database for hospitalizations in the USA from 2003 to 2014, we identified adult patients on ECMO support. Using International Classification of Diseases 9th Revision, we assessed the rates of AKI and AKI requiring dialysis (AKI-D) among them and associated survival. We used a multivariable logistic regression to identify risk factors of and differential effect of age on mortality from AKI. RESULTS: AKI was seen in 63.9% of 17,942 ECMO hospitalizations: 21.9% of those with AKI required dialysis. The percentage of those with AKI increased steadily. Mortality was higher in those with AKI, with highest in those with AKI-D (70.8% vs. 61.7%; p < 0.001). While both age and AKI were independent predictors of mortality, age was neither a risk factor for AKI nor did it modify the effect of AKI on mortality. CONCLUSIONS: AKI is common and is increasing among patients on ECMO support. Patients on ECMO have high mortality and AKI is an independent predictor of mortality. Though age is also an independent predictor of mortality in patients on ECMO, it is neither a predictor of AKI nor does not modify the relationship between AKI and mortality.

Safety of total dose iron dextran infusion in geriatric patients with chronic kidney disease and iron deficiency anemia.

There are limited data on total dose infusion (TDI) using iron dextran in geriatric chronic kidney disease (CKD) patients with iron-deficiency anemia (IDA). Our goal was to evaluate the safety of TDI in this setting. We conducted a retrospective chart review spanning a 5 year period (2002-2007), including all patients with CKD and IDA who were treated with iron dextran TDI. Patient demographics were noted, and laboratory values for creatinine, hemoglobin and iron stores were recorded pre- and post-dose. TDI diluted in normal saline was administered intravenously over 4-6 hours after an initial test dose. One hundred fifty-three patients received a total of 250 doses of TDI (mean ± SD=971 ± 175 mg); age was 69 ± 12 years and creatinine 3.3 ± 1.9 mg/dL. All stages of CKD were represented (stage 4 commonest). Hemoglobin and iron stores improved post-TDI (P<0.001). None of the patients experienced an anaphylactic reaction or death. Adverse events (AEs) were noted in 8 out of 250 administered doses (3.2%). The most common AEs were itching, chills and back pain. One hundred and ten doses of high molecular weight (HMW) iron dextran produced 6 AEs (5.45%), whereas 140 doses of low molecular weight (LMW) iron dextran produced 2 AEs (1.43%), a non-significant trend (P=0.1433 by Fishers Exact Test). Iron dextran TDI is relatively safe and effective in correcting IDA in geriatric CKD patients. Fewer AEs were noted with the LMW compared to the HMW product. LMW iron dextran given as TDI can save both cost and time, helping to alleviate issues of non-compliance and patient scheduling.

Successful treatment of intravenous drug abuser with refractory vasoplegic syndrome after mitral valve repair for infective endocarditis.

Vasoplegic syndrome, a possible complication of cardiopulmonary bypass, is a critical state of unregulated systemic vasodilation with decreased vascular resistance and a pathological insensitivity to conventional inotropes and vasoconstrictors. This case demonstrates the use of methylene blue and hydroxocobalamin as medications in the treatment of refractory vasoplegic syndrome in the context of cardiac surgery due to their differences in mechanism of action. A 24-year-old female with history of intravenous drug abuse and hepatitis C infection underwent mitral valve repair for infective endocarditis. Preoperative transesophageal echocardiography showed normal right ventricular function, left ventricular ejection fraction of 65%-75%, and severe mitral regurgitation with vegetation. In order to maintain a mean arterial pressure over 60 mmHg during cardiopulmonary bypass, norepinephrine, epinephrine, and vasopressin infusions were required. Given the patient's minimal response to these medications, a 1.5 mg/kg bolus of intravenous methylene blue was also given intraoperatively; vasoplegic syndrome remained refractory in the post-cardiopulmonary bypass period. A 5 g dose of intravenous hydroxocobalamin was administered in the intensive care unit postoperatively. Postoperative liver function tests were abnormal, and post-cardiopulmonary bypass transesophageal echocardiography revealed mildly decreased right ventricular function. While in the intensive care unit, the patient was placed on venoarterial extracorporeal membrane oxygenation and underwent therapeutic plasma exchange. Vasopressors were weaned over the course of the next 24 h. The patient was able to be transferred out of the intensive care unit on postoperative day 5. Traditional vasoconstrictors activate signal transduction pathways that lead to myosin phosphorylation. Vasodilatory molecules such as nitric oxide (NO) activate the enzyme soluble guanylyl cyclase (sGC), ultimately leading to the dephosphorylation of myosin. Nitric Oxide Synthase (NOS) can potentially increase NO levels 1000-fold when activated by inflammatory cytokines. Methylene blue is a direct inhibitor of NOS. It also binds and inhibits sGC. Hydroxocobalamin is a direct inhibitor of NO, likely inhibits NOS and may also act through additional mechanisms.

Derivation of acute ecological risk criteria for chlorite in freshwater ecosystems.

Chlorine dioxide has been proposed as an alternative to chlorine because it is a powerful disinfection agent that does not react with ammonia or chlorinated organics to form chloramines or trihalomethanes. The major reduction product formed when chlorine dioxide is added to water is the chlorite ion. Chlorite has been shown to be less toxic than free or combined chlorine. However, previous studies with eight freshwater families produced a US Environmental Protection Agency (USEPA) acute water quality criteria (WQC) lower than the WQC for chlorine. In the current study, an additional 12 families were added to the toxicological database to determine ecological risk criteria (ERC) using both the standard USEPA WQC methodology and the USEPA Office of Pesticide Programs (OPP) probabilistic approach. Chlorite LC50 values for the 20 family database ranged from 0.27 mg/L for the Daphnidae to 208.76 mg/L for the Salmonidae. The Daphnidae were by far the most sensitive family tested, with an LC50 44 times lower than the next most sensitive family tested, the Hyalellidae (LC50=1.19 mg/L) and 214 times lower than the most sensitive fish family tested, the Ictaluridae (LC50=5.79 mg/L). The Criteria Maximum Concentration calculated using the USEPA WQC methodology was 0.025 mg/L while the 95% ERC calculated using the USEPA OPP probabilistic methodology was 0.135 mg/L. The USEPA OPP probabilistic approach yields a criterion more consistent with the overall species sensitivity distribution and is not overly skewed by the low Daphnidae LC50 as is the USEPA WQC approach.

A field test and comparison of acute and chronic sediment toxicity tests with the estuarine amphipod Leptocheirus plumulosus in Chesapeake Bay, USA.

A 28-d partial life-cycle test with the estuarine amphipod Leptocheirus plumulosus was developed in response to the need for an assay to mimic chronic exposure to sediment-associated contaminants. To ensure that toxicity tests have environmental relevance, it is essential to evaluate the relationship between laboratory responses and field measures of contamination. Consequently, one objective of the study was to compare the results of the chronic sediment toxicity test with L. plumulosus to gradients of sediment contamination and the in situ benthic community in its native Chesapeake Bay. Chronic tests were conducted by two laboratories, the Army Corps of Engineers Waterways Experiment Station ([WES]; Vicksburg, MS, USA) and the University of Maryland ([UM] College Park, MD, USA) using different feeding regimes, providing the opportunity to evaluate the effect of this variable on response sensitivity. A second objective was to compare the relative sensitivity of acute and chronic tests with L. plumulosus with field-collected sediments. Overall, there was good agreement between the toxicological response of acute and chronic tests with L. plumulosus and field measures of contamination. Survival in the acute test and chronic test conducted by WES was negatively correlated with concentrations of sediment-associated contaminants. Survival in acute exposures was significantly reduced in sediments from 8 of 11 stations. Indigenous L. plumulosus were found only at two of the three stations that did not exhibit acute toxicity. An unexpected finding was the difference in responsiveness of the two chronic tests. Survival in tests conducted by UM and WES was significantly reduced in sediments from 4 and 6 of 11 stations, respectively. No additional sublethal toxicity was detected in the UM chronic test, but the WES test detected reproductive effects at two additional stations. We believe the observed differences were related to the test diet used. Partly as a result of our findings, the recommended diet for the L. plumulosus chronic test was changed in the final methods document.

Intravenous Iron Repletion Does Not Significantly Decrease Platelet Counts in CKD Patients with Iron Deficiency Anemia.

Purpose. We sought to investigate the effect of IV iron repletion on platelet (PLT) counts in CKD patients with iron deficiency anemia (IDA). Methods. We conducted a retrospective chart review, including all patients with CKD and IDA who were treated with iron dextran total dose infusion (TDI) between 2002 and 2007. Patient demographics were noted, and laboratory values for creatinine, hemoglobin (Hgb), iron stores and PLT were recorded pre- and post-dose. Results. 153 patients received a total of 251 doses of TDI (mean ± SD = 971 ± 175 mg); age 69 ± 12 years and Creatinine 3.3 ± 1.9 mg/dL. All CKD stages were represented (stage 4 commonest). Hgb and Fe stores improved post-TDI (P ≪ 0.001). There was a very mild decrease in PLT (pre-TDI 255 versus post-TDI 244, P = 0.30). The mild reduction in PLT after TDI remained non-significant (P > 0.05) when data was stratified by molecular weight (MW) of iron dextran used (low versus high), as well as by dose administered (<1000 versus ≥1000 mg). Linear regression analysis between pre-dose PLT and Tsat and Fe showed R2 of 0.01 and 0.04, respectively. Conclusion. Correction of iron deficiency did not significantly lower PLT in CKD patients, regardless of MW or dose used. Correlation of PLT to severity of iron deficiency was very weak.

Recovery of interior brackish marshes seven years after the chalk point oil spill.

Seven years after the April 2000 spill of 140,000 gallons of a mixture of No. 6 and No. 2 fuel oils in the Patuxent River, Maryland, heavily oiled brackish marshes showed continuing effects. Stem density and stem height were significantly lower in oiled versus unoiled sites for Spartina alterniflora but not Spartina cynosuroides habitats. In contrast, belowground biomass was significantly lower in S. cynosuroides habitats but not S. alterniflora habitats. Total PAH concentrations were up to 453 mg/kg in surficial soils (0-10 cm) and 2921 mg/kg with depth (10-20 cm). The oil had lost 22-76% of its initial PAH content after seven years, although the oil in marsh soils has undergone little to no additional weathering since Fall 2000. Based on amphipod acute toxicity tests and sediment quality guidelines, 25% of the soils in the marsh are expected to be toxic (ESB-TU(FCV) values>3.0; P(Max)>0.65).