A single-centre review of iatrogenic anaemia in adult intensive care.

OBJECTIVES: (a) To quantify the volume of diagnostic blood loss (DBL) and evaluate its impact on intensive care unit (ICU) patients, (b) examine the correlation between severity of disease and DBL and (c) identify potentially vulnerable patient subgroups. BACKGROUND: Iatrogenic anaemia is an important problem amongst ICU patients, with significant daily DBL. METHODS: A single-centre observational cohort study was conducted at St George's Hospital, London, cardiac and general ICU. Forty patients were included in the study. Variables measured were volume of blood collected and discarded on a daily basis, Acute Physiology and Chronic Health Evaluation (APACHE) II score, frequency of phlebotomy, haemoglobin concentration before and after admission to ICU, reason for admission and complications developed in ICU. RESULTS: Mean (SD) total volume drawn per patient per day over 4 days was 86.3 mL (19.58). Nearly 30% of the total blood taken was discarded. There was a strong positive correlation between patients admitted because of sepsis and volume of DBL (P < .01), APACHE II score and volume taken (P = .01), patients who developed respiratory failure requiring ventilation and volume taken (P < .01) and patients who had received a blood transfusion and volume taken (P < .01). Haemoglobin concentration on discharge was negatively associated with DBL volume (P < .01). CONCLUSION: High volumes of blood were taken and discarded from the study population, possibly reflecting the fact that there are no guidelines for ICU staff in terms of the amount of blood that needs to be withdrawn in order to "prime" access lines.

Characterization of soil bacterial community structure and physicochemical properties in created and natural wetlands.

We used multi-tag pyrosequencing of 16S ribosomal DNA to characterize bacterial communities of wetland soils collected from created and natural wetlands located in the Virginia piedmont. Soils were also evaluated for their physicochemical properties [i.e., percent moisture, pH, soil organic matter (SOM), total organic carbon (TOC), total nitrogen (TN), and C:N ratio]. Soil moisture varied from 15% up to 55% among the wetlands. Soil pH ranged between 4.2 and 5.8, showing the typical characteristic of acidic soils in the Piedmont region. Soil organic matter contents ranged from 3% up to 6%. Soil bacterial community structures and their differences between the wetlands were distinguished by pyrosequencing. Soil bacterial communities in the created wetlands were less dissimilar to each other than to those of either natural wetland, with little difference in diversity (Shannon's H') between created and natural wetlands, except one natural wetland consistently showing a lower H'. The greatest difference of bacterial community structure was observed between the two natural wetlands (R=0.937, p<0.05), suggesting these two natural wetlands were actually quite different reflecting differences in their soil physicochemistry. The major phylogenic groups of all soils included Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatinomadetes, Nitrospira, and Proteobacteria with Proteobacteria being the majority of the community composition. Acidobacteria group was more abundant in natural wetlands than in created wetlands. We found a significant association between bacterial community structures and physicochemical properties of soils such as C:N ratio (ρ=0.43, p<0.01) and pH (ρ=0.39, p<0.01). The outcomes of the study show that the development of ecological functions, mostly mediated by microbial communities, is connected with the development of soil properties in created wetlands. Soil properties should be carefully monitored to examine the progress of functional wetland mitigation.