Low Bicarbonate Levels Research Articles

Serum anion gap, bicarbonate and biomarkers of inflammation in healthy individuals in a national survey.

In vitro data suggest that lower extracellular pH activates the immune system. We conducted a population-based study of the relation between serum acid-base status and inflammation. We examined the serum anion gap and serum levels of bicarbonate and inflammatory biomarkers in 4525 healthy adults who participated in the National Health and Nutrition Examination Survey during 1999-2006. We excluded participants who had chronic disease, recent infection and an estimated glomerular filtration rate of less than 60 mL/min per 1.73 m2. The mean values of serum anion gap, bicarbonate level, leukocyte count and C-reactive protein level were all within normal limits. After adjustment for age, sex, ethnic background, body mass index, serum albumin level and other factors, we found that a higher anion gap and lower bicarbonate level were associated with a higher leukocyte count and higher C-reactive protein level. Compared with participants in the lowest quartile of anion gap, those in the highest quartile had a leukocyte count that was 1.0x10(9)/L higher and a C-reactive protein level that was 10.9 nmol/L higher (p<0.01). Compared with participants in the highest quartile of bicarbonate level, those in the lowest quartile had a leukocyte count that was 0.7x10(9)/L higher and a C-reactive protein level that was 4.0 nmol/L higher (p<or=0.02). A higher anion gap and lower bicarbonate level were also associated with a higher platelet count, a larger mean platelet volume and a higher ferritin level. A higher serum anion gap and lower bicarbonate level were associated with higher levels of inflammatory biomarkers in a healthy sample of the general population. Further studies are needed to elucidate the relation between acid-base status and inflammation.

Acid generation upon thermal concentration of natural water: The critical water content and the effects of ionic composition

Thermal evaporation of a variety of simulated pore waters from the region of Yucca Mountain, Nevada, produced acidic liquids and gases during the final stages of evaporation. Several simulated pore waters were prepared and then thermally distilled in order to collect and analyze fractions of the evolved vapor. In some cases, distillates collected towards the end of the distillation were highly acidic; in other cases the pH of the distillate remained comparatively unchanged during the course of the distillation. The results suggest that the pH values of the later fractions are determined by the initial composition of the water. Acid production stems from the hydrolysis of magnesium ions, especially at near dryness. Near the end of the distillation, magnesium nitrate and magnesium chloride begin to lose water of hydration, greatly accelerating their thermal decomposition to form acid. Acid formation is promoted further when precipitated calcium carbonate is removed. Specifically, calcium chloride-rich pore waters containing moderate (10–20 ppm) levels of magnesium and nitrate and low levels of bicarbonate produced mixtures of nitric and hydrochloric acid, resulting in a precipitous drop in pH to values of 1 or lower after about 95% of the original volume was distilled. Waters with either low or moderate magnesium content coupled with high levels of bicarbonate produced slightly basic fractions (pH 7–9). If calcium was present in excess of bicarbonate, waters containing moderate levels of magnesium produced acid even in the presence of bicarbonate, due to the precipitation of calcium carbonate. Other salts such as halite and anhydrite promote the segregation of acidic vapors from residual basic solids. The concomitant release of wet acid gas has implications for the integrity of the alloys under consideration for containers at the Yucca Mountain nuclear waste repository. Condensed acid gases at very low pH, especially mixtures of nitric and hydrochloric acid, are capable of corroding even alloys, such as nickel-based Alloy 22, which are considered to be corrosion-resistant under milder conditions.

The Prognostic Factor Evaluation of Febrile Neutropenia Before Chemotherapy to Hematologic Malignancies

Purpose Febrile neutropenia is one of the major toxicities-associated with chemotherapy especially in hematologic disorders. Thus, the occurrence of febrile neutropenia significantly can affect their treatment outcomes. But, it is difficult to predict their clinical courses and treatment outcomes. In this study, we analyzed the prechemothepeutic clinical characteristics of febrile neutropenia and their relationship with the prognosis of febrile neutropenia in the patients with hematologic malignancies.Methods We retrospectively analyzed 259 cases of febrile neutropenia developed after the chemotherapy for their hematologic malignacies from January 2006 to July 2008 at the Korea University Medical Center to identify the potential prognosis predicting factors. For the early detection of the high risk of febrile neutropenia, we focused on the findings before chemotherapy.Results With univariate analysis, age, underlying disease, recovery of neutropenia, onset time of febrile neutropenia, onset location, the duration of fever, infection sites, and type of cultured organism were significantly associated with mortality (p < 0.05). Also, the risk of mortality was significantly associated with laboratory findings (hemoglobin, platelet count, BUN, AST, albumin, sodium, bicarbonate, PT, ESR, CRP) of prechemotherapy. In multivariate analysis, only three variables of laboratory findings were associated with poor outcomes: albumin, bicarbonate and C-reactive protein of prechemotherapy. The recoveries of neutropenia and respiratory tract infection were also the significant risk factors in multivariate analysis. The complication rate in the patients who had three poor variables (low albumin & bicarbonate level and high CRP level) was 82.8%, while in the patient who had no poor variables was only 5.7%.Conclusion The levels of albumin, bicarbonate and CRP, in prechemotherapic condition were associated with the prognosis of febrile neutropenia in our study. Therefore, the further prospective studies will be warranted to confirm the result of this study.

The association between ketoacidosis and 25(OH)-vitamin D3levels at presentation in children with type 1 diabetes mellitus

There is considerable evidence supporting the role of vitamin D deficiency in the pathogenesis of type 1 diabetes mellitus (T1DM). Vitamin D deficiency is also associated with impairment of insulin synthesis and secretion. There have been no formal studies looking at the relationship between 25(OH)-vitamin D(3) and the severity of diabetic ketoacidosis (DKA) in children at presentation with T1DM. To determine the relationship between measured 25(OH)-vitamin D(3) levels and the degree of acidosis in children at diagnosis with T1DM. Children presenting with new-onset T1DM at a tertiary children's hospital. 25(OH)-vitamin D(3) and bicarbonate levels were measured in children at presentation with newly diagnosed T1DM. Those with suboptimal 25(OH)-vitamin D(3) levels (<50 nmol/L) had repeat measurements performed without interim vitamin D supplementation. Fourteen of the 64 children had low 25(OH)-vitamin D(3) levels at presentation, and 12 of these had low bicarbonate levels (<18 mmol/L) (p = 0.001). Bicarbonate explained 20% of the variation in vitamin D level at presentation (partial r(2) = 0.20, p < 0.001) and ethnic background a further 10% (partial r(2) = 0.10, p = 0.002). The levels of 25(OH)-vitamin D(3) increased in 10 of the 11 children with resolution of the acidosis. Acid-base status should be considered when interpreting 25(OH)-vitamin D(3) levels in patients with recently diagnosed T1DM. Acidosis may alter vitamin D metabolism, or alternatively, low vitamin D may contribute to a child's risk of presenting with DKA.

Medications and laboratory parameters as prognostic factors in amyotrophic lateral sclerosis

We sought to examine the influence of medication usage and laboratory measurements on disease progression in amyotrophic lateral sclerosis (ALS). A database of 596 volunteers with ALS was generated from three clinical trials and one observational study. Disease course was measured by survival and three functional measures: the ALS Functional Rating Scale (ALSFRS), Vital Capacity (VC) and Maximum Voluntary Isometric Contraction (MVIC). Survival modeling was performed using Cox proportional hazards regression. The association of medication or laboratory measurements with disease progression was determined using a random effects model. In the multivariate analysis, survival was shorter in participants who took aspirin (HR =1.93, p =0.046); NSAIDs (HR =1.51, p =0.054); had low blood chloride (HR =0.76, p =0.020) or high bicarbonate levels (HR =1.37, p =0.006). Individuals who took calcium had better survival (HR =0.37, p =0.008) and a slower rate of decline of MVIC arm megascore (p =0.033). Vital capacity declined faster in individuals with lower serum chloride (p<0.0001), or higher bicarbonate (p =0.002) levels and those taking paracetamol (acetaminophen) (p =0.035). We conclude that aspirin or NSAID use may shorten survival in ALS, while calcium use may prolong survival. Our results support a need to further explore the role of neuroinflammation in the pathogenesis of ALS.

Acute Tubular Injury Associated with Mesalazine Therapy in an Adolescent Girl with Inflammatory Bowel Disease

Mesalazine is a first-line drug in pediatric inflammatory bowel disease, and is effective as primary treatment and maintenance therapy. It's usually well tolerated, but various side effects have been described. A 15-year-old female with ulcerative colitis developed polyuria, polydipsia, vomiting, and fatigue. She was receiving mesalazine (500 mg, thrice daily, p.o.) and prednisolone for 4 months. She was detected as acute tubular injury as she had dehydration, acidosis, hypostenuria, hematuria, proteinuria, low levels of potassium, uric acid and bicarbonate. These findings were attributed to interstitial nephritis as a side effect of mesalazine, however as renal biopsy was disapproved by the parents, it was not confirmed. After discontinuation of mesalazine her renal tubular functions improved. Potassium and phosphorus supplements were stopped after 7 months, although she had to continue bicarbonate supplementation. We conclude that regular renal screening is important in patients receiving 5-ASA therapy to prevent rare but serious complications, such as interstitial nephritis sometimes leading to chronic renal failure.

The nephrologist in the HAART era

The nephrologist in the HAART era

413: Assessing the Clinical Parameters of Dehydration in the Pediatric Emergency Department Patient

It estimated that approximately 5% of pediatric emergency department visits are due to dehydration secondary to gastroenteritis. A low bicarbonate level of < 17 mEq/L is used as an indicator of dehydration in pediatric patients. An elevated anion gap has been noted in children with a metabolic acidosis secondary to dehydration. Clinical evaluation can assist in the assessment of fluid status, but the sensitivity and specificity of individual clinical parameters for predicting dehydration is moderate to poor.

Ultrasonographic Features and Severity Scoring of Periventricular Hemorrhagic Infarction in Relation to Risk Factors and Outcome

Early diagnosis of periventricular hemorrhagic infarction in premature infants is based on bedside neonatal cranial ultrasonography. Currently, evaluation of its morphology and evolution by cranial ultrasound relies largely on data predating major advances in perinatal care and lacks a consistent classification system for determining severity of injury. The objective of this study was to examine the ultrasonographic morphology and evolution of periventricular hemorrhagic infarction in the modern NICU and to determine the value of a cranial ultrasonography-based severity score for predicting outcome. We retrospectively evaluated all cranial ultrasounds and medical records of 58 premature infants with periventricular hemorrhagic infarction. We assigned each subject a severity score based on extent of echodensity, unilateral versus bilateral, and presence or absence of midline shift. A neurologic examination was performed after 12 months adjusted age. The parenchymal echodensity of periventricular hemorrhagic infarction most often involved parietal and frontal territories and evolved into single and/or multiple cysts. One quarter of cases were bilateral, and nearly 70% were extensive. Higher severity scores were significantly associated with pulmonary hemorrhage and low bicarbonate levels and with outcomes of fatality, early neonatal seizures, and motor disability. Despite advances in perinatal medicine, periventricular hemorrhagic infarction remains an important complication of prematurity. Periventricular hemorrhagic infarction can be graded using a scoring system based on sonographic characteristics. Higher severity scores predict worse outcome. Such severity scoring could improve the clinician's ability to counsel parents regarding management decisions and early intervention strategies.

Changing Electrolyte and Acido-Basic Profile in HIV-Infected Patients in the HAART Era

Background: HIV-infected patients may develop a variety of underreported metabolic abnormalities that may be classified into HIVAN, specific HIV abnormalities, coincidental renal disorders and anti-retroviral-treatment-induced side effects. Methods: Our descriptive cross-sectional study evaluates the prevalence of electrolyte and acid base disorders in HIV patients in the HAART era in a tertiary care teaching hospital. All consecutive HIV-infected patients (n = 1,232) presenting at our Department of Infectious Disease over 3 months were included. Measurements: All available biochemical data obtained at admission or on the day of the visit were analyzed. We identified risk factors for electrolyte and acid base disorders with univariate regression analysis and multivariate stepwise regression analysis. Variables tested for significance included age, sex, absolute CD4 and CD8 counts, hepatitis B and C antibodies, and use and type of anti-retroviral medication. Results: Most frequent and clinically relevant abnormalities were hyperuricemia in 41.3%, hypophosphatemia in 17.2% and low bicarbonate level in 13.6% of HIV-tested patients. Plasma magnesium was out of the normal range in 38.9% and blood glucose in 25.3% of the tested patients. When CD4 count was below 200/mm³, 9.2% of tested patients experienced low serum calcium (vs. 0.5% if CD4 count >200/mm³, p < 0.002), 11.4% increased creatinine plasma level (vs. 2.3% if CD4 count >200/mm³, p < 0.0001) and 24.5% low serum bicarbonate (vs. 13.7% if CD4 count >200/mm³, p < 0.0001). Protease inhibitor treatment was a significant risk factor of hyperuricemia (p < 0.003). Non-nucleoside reverse transcriptase inhibitor therapy was significantly associated with less hyperuricemia (OR = 0.6, 95% CI 0.38–0.96) and with hypophosphatemia (OR = 2.0, 95% CI 1.1–3.4). Conclusions: The profile of biochemical abnormalities in HIV-infected patients has changed, hyperuricemia and hypophosphatemia being the most prevalent. Causes are poorly understood. Interpretation of drug-induced side effects in the HIV patient is only meaningful if performed versus a control group of patients.

Necrotizing Soft Tissue Infections of the Extremities and Back

Necrotizing soft tissue infections are potentially fatal infections that often involve extremities. Studies of mixed anatomic sites suggest several factors increase mortality (eg, age, medical comorbidities, laboratory values, treatment timing). We hypothesized that patients with necrotizing soft tissue infections of the extremities would have similar factors associated with mortality. We retrospectively reviewed 150 patients with necrotizing soft tissue infections of the extremities treated at San Francisco General Hospital from 1993-1997. We recorded cofactors, treatment, physical findings, radio- graphs, and laboratory findings at presentation. No cofactor or examination finding was associated with increased mortality. Compared with survivors, nonsurvivors had a higher leukocyte count, blood urea nitrogen, creatinine, potassium, partial thromboplastin time, and aspartate aminotransferase, but had lower pH and bicarbonate. Nonsurvivors did not have delays in treatment relative to survivors. Univariate analysis showed an increased risk of mortality in patients with hypotension, hypothermia, Clostridium species in the wound culture, low leukocyte count and bicarbonate levels, and elevated blood urea nitrogen, aspartate aminotransferase, creatinine, and potassium levels. Several signs of shock and organ dysfunction were associated with mortality in patients with necrotizing soft tissue infections of the extremities. The overall mortality rate (9.3%) was lower than in some other reports.

Pilot-Scale in Situ Bioremedation of Uranium in a Highly Contaminated Aquifer. 2. Reduction of U(VI) and Geochemical Control of U(VI) Bioavailability

In situ microbial reduction of soluble U(VI) to sparingly soluble U(IV) was evaluated at the site of the former S-3 Ponds in Area 3 of the U.S. Department of Energy Natural and Accelerated Bioremediation Research Field Research Center, Oak Ridge, TN. After establishing conditions favorable for bioremediation (Wu, et al. Environ. Sci. Technol. 2006, 40, 3988-3995), intermittent additions of ethanol were initiated within the conditioned inner loop of a nested well recirculation system. These additions initially stimulated denitrification of matrix-entrapped nitrate, but after 2 months, aqueous U levels fell from 5 to approximately 1 microM and sulfate reduction ensued. Continued additions sustained U(VI) reduction over 13 months. X-ray near-edge absorption spectroscopy (XANES) confirmed U(VI) reduction to U(IV) within the inner loop wells, with up to 51%, 35%, and 28% solid-phase U(IV) in sediment samples from the injection well, a monitoring well, and the extraction well, respectively. Microbial analyses confirmed the presence of denitrifying, sulfate-reducing, and iron-reducing bacteria in groundwater and sediments. System pH was generally maintained at less than 6.2 with low bicarbonate level (0.75-1.5 mM) and residual sulfate to suppress methanogenesis and minimize uranium mobilization. The bioavailability of sorbed U(VI) was manipulated by addition of low-level carbonate (< 5 mM) followed by ethanol (1-1.5 mM). Addition of low levels of carbonate increased the concentration of aqueous U, indicating an increased rate of U desorption due to formation of uranyl carbonate complexes. Upon ethanol addition, aqueous U(VI) levels fell, indicating that the rate of microbial reduction exceeded the rate of desorption. Sulfate levels simultaneously decreased, with a corresponding increase in sulfide. When ethanol addition ended but carbonate addition continued, soluble U levels increased, indicating faster desorption than reduction. When bicarbonate addition stopped, aqueous U levels decreased, indicating adsorption to sediments. Changes in the sequence of carbonate and ethanol addition confirmed that carbonate-controlled desorption increased bioavailability of U(VI) for reduction.

Short-term and long-term mortality in very elderly patients admitted to an intensive care unit

To report short-term and long-term mortality of very elderly ICU patients and to determine independent risk factors for short-term and long-term mortality Retrospective cohort study in the medical/surgical ICU of a tertiary university teaching hospital. 578 consecutive ICU patients aged 80 years or older. Demographic, physiological, and laboratory values derived from the first 24h after ICU admission. ICU mortality of unplanned surgical (34.0%) and medical patients (37.7%) was higher than that of planned surgical patients (10.6%), as was post-ICU hospital mortality (26.5% and 29.7% vs. 4.4%). Mortality 12 months after hospital discharge, including ICU and hospital mortality, was 62.1% in unplanned surgical and 69.2% in medical patients vs. 21.6% in planned patients. Only median survival of planned surgical patients did not differ from survival in the age- and gender-matched general population. Independent risk factors for ICU mortality were lower Glasgow Coma Scale score, higher SAPS II score, the lowest urine output over 8 h, abnormal body temperature, low plasma bicarbonate levels, and higher oxygen fraction of inspired air. High urea concentrations and admission type were risk factors for hospital mortality, and high creatinine concentration was an independent risk factor for 12-month mortality. Mortality in very elderly patients after unplanned surgical or medical ICU admission is higher than after planned admission. The most important factors independently associated with ICU mortality were related to the severity of illness at admission. Long-term mortality was associated with renal function.

Comportamiento clínico y costos de la gastroenteritis por rotavirus en lactantes: Adquisición comunitaria versus nosocomial

This is a prospective 12 month (July 2003-June 2004) cohort study in one large tertiary hospital of Santiago, Chile aimed to describe clinic features and calculate the direct costs of hospitalization associated to community-acquired (n = 78) and nosocomially-acquired (n = 52) rotavirus infection. A gastroenteritis severity score after Rennels 1996, (0 to 17 points) was applied and costs where calculated based on those assigned by the Chilean National Funds for Health (FONASA). Severe gastroenteritis manifested by a score > 14 occurred in 26.9% and 9.6% of community and nosocomially-acquired cases respectively (p < 0.015). The former had lower bicarbonate levels (p < 0.001), and required more volume expansion compared to the latter (p < 0.023). The average cost was US 277 per case for community acquired rotavirus and US 268 for nosocomial infection. In this hospital the cost of nosocomial rotavirus infection was approximately 13,900 US dollars for a 12 month period. These results should stimulate the implementation of active prevention and control programs.

Bicarbonate inhibits the growth of Staphylococcus epidermidis in platelet concentrates by lowering the level of non‐transferrin‐bound iron

Platelet concentrates (PCs) contain non-transferrin-bound iron (NTBI) owing to the displacement of iron from plasma-derived transferrin by citrate. NTBI in the PC medium supports the growth of Staphylococcus epidermidis. The possibilities of lowering the level of NTBI have been studied with the aim to inhibit the growth of S. epidermidis in the PC medium. NTBI in PC supernatants was determined by a chelation method and by the bleomycin-detectable iron assay. Iron binding by transferrin was determined by spectrophotometry. The growth of inoculated S. epidermidis in PC supernatants was monitored by optical density and determination of viable counts. Bicarbonate enhanced in a dose-dependent manner transferrin iron binding in citrate-containing solutions, including citrated plasma and PAS-II. The use of a modified anticoagulant supplemented with bicarbonate effectively lowered the level of NTBI and inhibited bacterial growth in citrated plasma. Supplementation of bicarbonate to the additive solution to increase the ratio of bicarbonate to citrate in a reconstituted PC medium further inhibited bacterial growth. Maintenance of stable pH and bicarbonate level in the reconstituted medium necessitated storage under 5 percent CO(2). The relatively low bicarbonate level in PC medium promotes iron displacement by citrate from plasma-derived transferrin. The appearance of NTBI can be decreased and iron-dependent bacterial growth can be inhibited by increasing bicarbonate level in citrated plasma and PC medium. To achieve the same beneficial effect in blood banking, other more practical ways to bind NTBI in a harmless form should be developed.

Hyponatraemia for the clinical endocrinologist

Hyponatraemia for the clinical endocrinologist

Donor Characteristics Associated with Liver Graft Survival

Organ availability is affecting the development of liver transplantation in its entirety, leading to transplant teams expanding the criteria for accepting organ donors. In these circumstances, analysis of the impact of the donor's characteristics on graft survival becomes mandatory. Fifty-two donor variables from 5,150 liver transplants performed in Spain between 1994 and 2001 were analyzed through a univariate analysis. Those with statistically significant impact on graft survival were entered in a Cox regression model with the recipients' characteristics and other factors linked to the graft technique. Several donor factors negatively affect graft survival: donor age, cause of death, body mass index, vasoactive drug administration, prolonged intensive care unit (ICU) stay, increased alkaline phosphatase and liver enzyme levels, low bicarbonate level, and antecedents of hypertension. However, only four can be mentioned as representing a risk for losing the graft when donor variables are controlled with recipient or technique variables in a Cox regression model: donor age, antecedents of hypertension, prolonged ICU stay, and low bicarbonate level. In the same analysis, norepinephrine administration has a relative risk less than 1. The multivariate analysis of the impact of 52 donor characteristics on liver graft survival showed the negative effect of an elderly donor, with hypertension combined with the presence of metabolic acidosis, or a prolonged ICU donor stay. The administration of norepinephrine alone during donor management showed a protective effect.

HIV infection--a risk factor for osteoporosis.

Osteopenia and osteoporosis have recently been described as complications of antiretroviral therapy in HIV-infected patients. The advent of highly active antiretroviral therapy in conjunction with improved standard antiviral and antibiotic regimens has dramatically changed the clinical course of HIV infection, resulting in prolonged survival. The pathogenesis and role of each individual medication are poorly understood. Avascular necrosis has also been described in AIDS patients receiving or not receiving antiretroviral therapy. This article is a clinically focused review of the literature on osteopenia, osteoporosis, and mineral metabolism related to HIV infection. In patients with HIV infection, the risks of osteopenia and osteoporosis are not very clear. The suggested risk factors for the development of osteopenia are use of protease inhibitors, longer duration of HIV infection, high viral load, high lactate levels, low bicarbonate levels, raised alkaline phosphatase level, and lower body weight before antiretroviral therapy. There have also been a few case reports of pathologic fractures in AIDS patients with antiretroviral therapy-induced osteopenia and osteoporosis. The underlying mechanism triggering bone loss in HIV-infected patients is unknown. The proinflammatory cytokines tumor necrosis factor and interleukin-6 have been found to be constitutionally produced in increased amounts in HIV-positive individuals, and they may have a role in osteoclast activation and resorption. Serum markers of bone formation are decreased and resorption is increased in patients with advanced clinical disease. Hypocalcemia, hypercalcemia, and abnormalities of the parathyroid hormone axis have been described in HIV infection. Histomorphometric analyses have shown altered bone remodeling in HIV-infected patients when compared with controls. Patients with known risk factors for osteoporosis-advancing age, low body weight, and prolonged duration of HIV infection-and those receiving protease inhibitor treatment should be considered for dual x-ray absorptiometry imaging. If bone mineral density is osteopenic or osteoporotic, then the patient should also be screened for other known medical causes of osteoporosis and consider treatment with a bisphosphonate or, if hypogonadal, testosterone replacement under close monitoring.

Utility of Serum Electrolytes in the Management of Dehydration 391

Background: The serum electrolyte panel (SEP) is a frequently ordered laboratory test and of unproved utility in the management of dehydrated pediatric patients. Many clinicians believe that the bicarbonate level may be predictive of patient outcome. Our purpose is to study the incidence of SEP abnormalities and assess their role in management.Methods: Children between the ages of 2 months and 18.8 years receiving intravenous fluids for dehydration were prospectively studied. Historical data, physical examination findings, degree of dehydration and SEP were obtained. Attending physicians documented prior to knowing laboratory results whether they would have ordered a SEP. Outcome measures included changes of management based on SEP, disposition, and return visits within 48 hours. Results: 206 patients were entered with a median age of 19.2 months. 123 patients presented with mild (≤5%), 81 with moderate (6-10%) and 2 with severe dehydration (>10%). The incidence of SEP abnormalities was 46% for one or more abnormal values. 29% had BUN levels > 17mg/dl, 26% had bicarbonate levels 150mmol/L. Considering the 54 patients with bicarbonates <16mmol/L; 27 were discharged home, 22 were placed into observation and 5 were admitted. At 95% significance, bicarbonate was lower in those placed into the observation unit versus those discharged home. There was no correlation between low bicarbonate and admission rates or return visits. The attending thought a SEP was needed in 33% of the cases. Knowing the SEP did not change management in 91%. In 17 patients the SEP changed management; 5 with low glucose values received glucose sooner, 5 with low bicarbonate levels were observed longer, 3 with reassuring values were sent home sooner, and 2 with low potassium levels received potassium. There were 10 return visits requiring IV fluids within 48 hours, 8 (2 with bicarbonates <16) were admitted. Conclusion: Although there were a large number of SEP abnormalities, there was minimal effect on clinical management or patient outcome. Low bicarbonate levels were predictive of observation unit placement but not for need of hospitalization or patient return visits.

Restoration of eutrophied shallow softwater lakes based upon carbon and phosphorus limitation

Plant communities from oligotrophic, poorly buffered waters are seriously threatened by both, acidification and eutrophication/alkalinization. Acidification is mainly caused by atmospheric deposition of acidifying substances while eutrophication is often the result of inlet of nutrient enriched, calcareous brook- or groundwater. The plant production in very soft waters is often limited by low levels of inorganic carbon, nitrogen and/or phosphorus. This paper deals with the possibilities for restoration of formerly oligotrophic but now eutrophied and alkalinized softwater systems. Restoration based upon nitrogen limitation is not likely to be successful as the atmospheric deposition of nitrogen in The Netherlands is very high. Phosphorus limitation can also be a problem. One can stop the input of phosphorus and remove the mud layer, but the problem remains that also the deeper mineral sandy sediments are saturated with phosphate. A possible remedy, however, is a combination of carbon- and phosphorus limitation. Many plants from eutrophic environments never occur in very soft waters, probably as a result of carbon limitation. In addition, mobilisation of phosphate is much lower in waters with very low bicarbonate levels. Restoration of a former oligotrophic softwater lake by reducing the inlet of calcareous surface water, in combination with removal of the organic sediment layer, appeared to be very successful. Many endangered plant species such asIsoetes echinospora, Luronium natans, Deschampsia setacea andEchinodorus repens developed spontaneously from the still viable seedbank.