Prophylactic infusion of calcium gluconate to prevent a symptomatic fall in plasma ionized calcium during therapeutic plasma exchange: A comparison of two methods.

We compared two methods of calcium gluconate infusion to maintain plasma ionized calcium ([Ca2+ ]) during therapeutic plasma exchange (TPE) performed using the Spectra Optia Apheresis System. Method A, our legacy method, consisted of adding 5 mL of 10% calcium gluconate to each 500 mL bottle of 5% albumin replacement fluid. Method B used an accessory IV infusion of calcium gluconate (2 g in 50 mL of 0.9% NaCl starting at 25 mL/h). Plasma [Ca2+ ] was measured at 20-minute intervals, and symptoms of hypocalcemia were recorded during TPE. Baseline [Ca2+ ] was the same (P = 0.616), as was total acid citrate dextrose Formula A used (P = 0.865), with either method. TPE with method A used 2.62 ± 0.52 g of calcium gluconate vs 1.13 ± 0.27 g with method B (P < 0.001). [Ca2+] remained stable with method A (P = 0.251), but fell on average by 5% with method B (P < 0.05). Hypocalcemic symptoms were reported in 0 of 23 TPE with method A and 2 of 24 TPE with method B. We conclude that both methods A and B prevent a symptomatic fall in plasma [Ca2+ ] during TPE. Method B requires significantly less calcium gluconate than does method A.

Dietary citrate and plasma ionized calcium: Implications for platelet donors.

BACKGROUND: Platelet donors receive 40 mmol or more of IV citrate anion during donation. When plasma ionized calcium ([Ca2+ ]) falls by ∼20%, half of the donors report symptoms of hypocalcemic toxicity. Citrus juices contain clinically relevant amounts of citrate anion. We asked whether citrus juice can lower [Ca2+ ] thus potentially contributing to hypocalcemic toxicity. METHOD: Six volunteers were given 20.4 mmol of citrate anion as grapefruit juice or orange juice. Capillary blood obtained by fingerstick was analyzed for [Ca2+ ] using an iSTAT point-of-care blood analyzer. [Ca2+ ] was measured at baseline and then 30, 60, 120, and 180 minutes after drinking juice. Subjects were tested with the alternative juice on a subsequent day. The outcome measure was the percent change in plasma [Ca2+ ] from baseline. RESULTS: [Ca2+ ] fell -2.2% to -11.5% in four of six subjects 30 minutes after drinking grapefruit juice. The effect persisted up to 3 hours. [Ca2+ ] fell -2.1% to -12.2% in four of six subjects 30-60 minutes after drinking orange juice. The effect abated after 2 hours. We could not correlate gender or body surface area to these findings. SUMMARY AND CONCLUSIONS: Citrus juice may lower [Ca2+ ] for 2-3 hours. This could add to the effect of IV citrate infusion during platelet donation, thus worsening the expected fall in [Ca2+ ]. This, in turn, would likely increase the rate and severity of hypocalcemic toxicity. It is prudent to advise platelet donors to avoid high citrate anion beverages, such as citrus juice, for at least 4 hours prior to donation.

A liquid calcium+vitamin D3 supplement is effective prophylaxis against hypocalcemic toxicity during apheresis platelet donation.

Hypocalcemic toxicity, because of return of citrate anion to the donor, is the major toxicity of apheresis platelet donation. Oral calcium carbonate, given prophylactically at the start of donation, has shown limited ability to alleviate this toxicity. We examined whether repeated prophylactic doses of calcium carbonate, or of a liquid preparation containing calcium citrate, calcium phosphate, and vitamin D3 , would be more effective at preventing symptoms of hypocalcemic toxicity. Symptoms were reported by 48% of donors who received no prophylaxis and 60% of donors who received 1000 mg of oral calcium carbonate at the start of, and every 20 minutes during, donation (P = 0.711). Only 19.2% of donors who received the liquid preparation (1000 mg calcium, 1000 IU vitamin D3 ) reported symptoms (P = 0.040 versus no prophylaxis, P = 0.039 versus calcium carbonate). This difference was not because of gender, weight, age, or blood volume of the donor. Neither calcium preparation prevented a measurable fall in plasma ionized calcium during donation. We conclude that liquid calcium citrate/calcium phosphate/vitamin D3 provides effective prophylaxis against hypocalcemic toxicity during platelet donation, however it does not prevent a fall in plasma ionized calcium.

A Markov model for planning and permitting offshore wind energy: A case study of radio-tracked terns in the Gulf of Maine, USA.

Quantifying and managing the potential adverse wildlife impacts of offshore wind energy is critical for developing offshore wind energy in a sustainable and timely manner, but poses a significant challenge, particularly for small marine birds that are difficult to monitor. We developed a discrete-time Markov model of seabird movement around a colony site parameterized by automated radio telemetry data from common terns (Sterna hirundo) and Arctic terns (S. paradisaea), and derived impact functions that estimate the probability of collision fatality as a function of the distance and bearing of wind turbines from a colony. Our purpose was to develop and demonstrate a new, flexible tool that can be used for specific management and wind-energy planning applications when adequate data are available, rather than inform wind-energy development at this site. We demonstrate how the tool can be used 1) in marine spatial planning exercises to quantitatively identify setback distances under development scenarios given a risk threshold, 2) to examine the ecological and technical trade-offs of development alternatives to facilitate negotiation between objectives, and 3) in the U.S. National Environmental Policy Act (NEPA) process to estimate collision fatality under alternative scenarios. We discuss model limitations and data needs, and highlight opportunities for future model extension and development. We present a highly flexible tool for wind energy planning that can be easily extended to other central place foragers and data sources, and can be updated and improved as new monitoring data arises.

Therapeutic apheresis using a mononuclear cell program to lower the microfilaria burden of a 23-year-old African woman with loiasis.

Apheresis has been used to lower the parasite burden of patients with Loa loa infection, but there are no reports regarding how to do this using modern, continuous flow equipment with a currently available program. A 23-year-old female refugee from Cameroon with known Loa loa infection presented to our Emergency Department with acute mental status changes and a picture of encephalitis. Lumbar puncture revealed Loa loa in her cerebrospinal fluid. Her midday blood microfilaria count was 15,000/mL. Because treatment with diethylcarbamazine was under consideration, we were asked to lower her parasite burden using apheresis. One single 2-total blood volume apheresis using the mononuclear cell program (without hydroxyethyl starch) on a COBE® Spectra Apheresis System decreased the microfilarial load from 15,000/mL to 10,666/mL, a 29% reduction. J. Clin. Apheresis 32:200-202, 2017. © 2016 Wiley Periodicals, Inc.

Automated red blood cell exchange for acute drug removal in a patient with sirolimus toxicity.

Sirolimus is an immunosuppressant used to prevent graft versus host disease in allogeneic hematopoietic stem cell transplant recipients. It has a large volume of distribution (12 ± 7.5 l/kg) and within the intravascular space ∼95% of it is bound to red blood cells. Because of potential toxic effects at high trough levels, therapeutic drug monitoring is recommended for sirolimus. We present a case of severe hepatic dysfunction due to Hepatitis B and sirolimus toxicity, in a 51-year-old male stem cell transplant recipient. An automated red cell exchange decreased his blood sirolimus level from 22.6 to 10.3 ng/ml (55% reduction) and improved his liver enzymes. Re-equilibration of sirolimus from other compartments to the blood necessitated a series of four red cell exchanges, after which the sirolimus level was 4.7 ng/ml. Although the patient ultimately succumbed to multiorgan failure, red cell exchange may be considered for acute removal of sirolimus in selected patients.

Use of the electroretinogram in a paediatric hospital.

BACKGROUND: To review the use of electroretinography and identify common reasons for referral and diagnoses at a tertiary paediatric hospital. DESIGN: Retrospective cohort study. PARTICIPANTS: Three hundred and eighteen patients (male 195, female 123) aged <18 years with 388 electroretinograms were included. METHODS: All electroretinograms performed at the Royal Children's Hospital, Brisbane from 1998 to 2005 were reviewed. Normative data and electroretinograms from patients aged ≥18 years were excluded. MAIN OUTCOME MEASURES: Reasons for referral and diagnoses were determined from each patient's first electroretinogram. Concordance between the first electroretinogram diagnosis and clinical referral was reviewed to determine whether the electroretinogram was normal, inconclusive, confirmed, excluded, or changed the clinical diagnosis or provided a new diagnosis. RESULTS: The median age at the time of the first investigation was 3.78 years (range 2.6 weeks to 17.5 years). The most common reasons for referral were nystagmus (n = 93), decreased vision (n = 33) and sensorineural deafness (n = 29). After one electroretinogram, 51% were normal (n = 162) and 15% were inconclusive (n = 49). The most common electroretinography diagnosis was cone rod dystrophy. The first electroretinogram for each patient confirmed the clinical suspicion in 17.6% (n = 56) and excluded it in 23% (n = 73) of cases. The electroretinogram resulted in a changed diagnosis in 0.9% (n = 3) and provided a new diagnosis in 15.1% (n = 48). Overall, the first electroretinogram was considered useful in 85% cases (n = 269). CONCLUSIONS: Electroretinography is a valuable investigation for evaluating paediatric eye disease and in this series confirmed, excluded, changed or provided a new diagnosis in 85% of cases.

Marine foraging birds as bioindicators of mercury in the Gulf of Maine.

From existing databases, we compiled and evaluated 604 total mercury (Hg) levels in the eggs and blood of 17 species of marine foraging birds from 35 Gulf of Maine islands to provide baseline data and to determine the best tissue, age class, and species for future biomonitoring. While mean Hg levels in most species did not exceed adverse effects thresholds, levels in some individual eggs did; for all species arithmetic mean egg Hg levels ranged from 0.04 to 0.62 (microg/g, wet weight). Piscivorous birds had higher Hg levels than invertivores. Leach's storm-petrel (Oceanodroma leucorhoa), razorbill (Alca torda), and black guillemot (Cepphus grylle) adult blood and egg Hg levels were higher than other species. Our results indicate that adult blood is preferable to chick blood for detecting long-term temporal trends because adult levels are higher and not confounded by metabolic effects. However, since we found that eggs and adult blood are comparable indicators of methylmercury bioavailability, we determined that eggs are the preferred tissue for long-term Hg monitoring because the relative ease in collecting eggs ensures consistent and robust datasets. We suggest specific sampling methods, and based on our results demonstrate that common eider (Somateria mollissima), Leach's storm-petrel, double-crested cormorant, and black guillemot are the most effective bioindicators of Hg of the Gulf of Maine.