Common Era sea-level budgets along the U.S. Atlantic coast.

Sea-level budgets account for the contributions of processes driving sea-level change, but are predominantly focused on global-mean sea level and limited to the 20th and 21st centuries. Here we estimate site-specific sea-level budgets along the U.S. Atlantic coast during the Common Era (0-2000 CE) by separating relative sea-level (RSL) records into process-related signals on different spatial scales. Regional-scale, temporally linear processes driven by glacial isostatic adjustment dominate RSL change and exhibit a spatial gradient, with fastest rates of rise in southern New Jersey (1.6 ± 0.02 mm yr-1). Regional and local, temporally non-linear processes, such as ocean/atmosphere dynamics and groundwater withdrawal, contributed between -0.3 and 0.4 mm yr-1 over centennial timescales. The most significant change in the budgets is the increasing influence of the common global signal due to ice melt and thermal expansion since 1800 CE, which became a dominant contributor to RSL with a 20th century rate of 1.3 ± 0.1 mm yr-1.

Publisher Correction: Cosmogenic exposure dating reveals limited long-term variability in erosion of a rocky coastline.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Cosmogenic exposure dating reveals limited long-term variability in erosion of a rocky coastline.

Predicted sea-level rise and increased storminess are anticipated to lead to increases in coastal erosion. However, assessing if and how rocky coasts will respond to changes in marine conditions is difficult due to current limitations of monitoring and modelling. Here, we measured cosmogenic 10Be concentrations across a sandstone shore platform in North Yorkshire, UK, to model the changes in coastal erosion within the last 7 kyr and for the first time quantify the relative long-term erosive contribution of landward cliff retreat, and down-wearing and stripping of rock from the shore platform. The results suggest that the cliff has been retreating at a steady rate of 4.5 ± 0.63 cm yr-1, whilst maintaining a similar profile form. Our results imply a lack of a direct relationship between relative sea level over centennial to millennial timescales and the erosion response of the coast, highlighting a need to more fully characterise the spatial variability in, and controls on, rocky coast erosion under changing conditions.

Comparison of pre-filter and post-filter ionised calcium monitoring in continuous veno-venous hemodiafiltration (CVVHD-F) with citrate anti-coagulation.

BACKGROUND: It is widespread practice during citrate anticoagulated renal replacement therapy to monitor circuit ionised calcium (iCa2+) to evaluate the effectiveness of anticoagulation. Whether the optimal site to sample the blood path is before or after the haemofilter is a common question. METHODS: Using a prospectively collected observational dataset from intensive care patients receiving pre-dilution continuous veno-venous haemodiafiltration (CVVHD-F) with integrated citrate anticoagulation we compared paired samples of pre and post filter iCa2+ where the target range was 0.3-0.5 mmol.L-1 as well as concurrently collected arterial iCa2+. Two nested mixed methods linear models were fitted to the data describing post vs pre filter iCa2+, and the relationship of pre, post and arterial samples. SETTING: An 11 bed general intensive care unit. PARTICIPANTS: 450 grouped samples from 152 time periods in seven patients on CRRT with citrate anticoagulation. RESULTS: The relationship of post to pre-filter iCa2+ was not 1:1 with post = 0.082 + 0.751 x pre-filter iCa2+ (95% CI intercept: 0.015-0.152, slope 0.558-0.942). Variation was greatest between patients rather than between circuits within the same patient or citrate dose. Compared to arterial iCa2+ there was no significant difference between pre and post-filter sampling sites (F-value 0.047, p = 0.827). CONCLUSION: These results demonstrate that there is minimal difference between pre and post filter samples for iCa2+ monitoring of circuit anticoagulation in citrate patients relative to the arterial iCa2+ in CVVHD-F however compared to pre-filter sampling, post filter sampling has a flatter response and greater variation.

Vascular access site influences circuit life in continuous renal replacement therapy.

OBJECTIVE: To determine the influence of vascular access site on continuous renal replacement therapy (CRRT) filter survival. DESIGN, SETTING AND PATIENTS: Retrospective study of the records of patients who received CRRT in The Alfred intensive care unit from June 2011 to May 2012. MAIN OUTCOME MEASURE: Filter run time. METHODS: We matched filter run time to site and type of vascular access. Mean run times were compared using a linear mixed-effects model between: temporary femoral, internal jugular (IJ) and subclavian catheters, tunnelled semipermanent IJ catheters, and extracorporeal membrane oxygenation (ECMO) circuit access. The Markov chain Monte Carlo method was used to construct 95% confidence intervals, and the Wilcoxon rank sum test was used for post hoc testing of significance. RESULTS: Filter run-time data were available for 131 patients (191 occasions of vascular access) with a total of 870 individual filters analysed. Mean run times were subclavian, 14.4 h; IJ, 17.1 h; femoral, 20.2 h; tunnelled IJ, 25.2 h; and ECMO, 29.0 h. Differences were significant for all combinations except between subclavian and IJ, and between tunnelled access and ECMO. Sites in order of best performing to worst-performing were ECMO circuit, tunnelled IJ, femoral vein, direct IJ vein, and subclavian vein. CONCLUSION: Vascular access for CRRT plays a significant role in determining filter life. Our study suggests that for temporary dialysis catheters the femoral site should be favoured in ICU patients, and if CRRT is likely to continue for an extended period, a tunnelled IJ line should be considered.

Randomised trial of software algorithm driven regional citrate anticoagulation versus heparin in continuous renal replacement therapy: the Filter Life in Renal Replacement Therapy pilot trial.

OBJECTIVE: The effectiveness of continuous renal replacement therapy (CRRT) increases when unplanned circuit failure is prevented. Adequate anticoagulation is an important component. Although heparin is the predominating anticoagulant, calcium chelation with citrate is an alternative, but systemic calcium monitoring and supplementation increase the complexity of CRRT. We assessed efficacy and safety of citrate delivery via integrated software algorithms against an established regional heparin protocol. DESIGN: Prospective computer randomisation allocated eligible patients to regional citrate or heparin between April and December 2012. Citrate fluids were Prismocitrate 18 mmol/L predilution and Prism0cal B22 dialysate. Hemosol B0 was the default fluid for heparin. The primary outcome was filter running time. Electively terminated circuits were censored. Intention-totreat (ITT) and per-protocol analyses were performed. Filter survival was compared by log-rank tests and hazard ratios were explored with a mixed-effects Cox model. RESULTS: 221 filters were analysed from 30 patients (of whom 19 were randomly allocated to citrate filters and 11 to heparin filters). Patients randomly allocated to citrate were older, sicker, with a higher male:female ratio, but of similar weight. Mortality was 37% in the citrate arm and 27% in the heparin arm. All deaths were attributed to underlying disease. Significant crossover occurred from the citrate arm to use of heparin. Median filter survival, by ITT, was not significantly different (citrate, 34 hours; heparin, 30.7 hours; P=0.58). Per-protocol survival favoured citrate (citrate, 42.1 hours; heparin, 24 hours; χ(2)=8.1; P=0.004). Considerable variation in filter life existed between patients, and between vascular access sites within patients. Safety end points were reached in one heparin and three citrate patients. CONCLUSION: Although the per-protocol results favoured citrate when it was actually delivered, the significant crossover between treatment arms hampered more definitive conclusions. Until further studies support improved patient outcomes, increased complexity and complications suggest that anticoagulation choice be made using patient-specific indications.