Volcanic ash in the water column: Cellular, physiological and anatomical implications for the gastropod suspension-feeder Crepipatella peruviana (Lamarck, 1822).

The influx of volcanic ash into seawater alters particle composition with implications for the cellular, physiological and anatomical response of suspension-feeding organisms. Adult females of Crepipatella peruviana were exposed to three diets consisting of a fixed concentration of 50,000 cells ml-1 of the microalga Isochrysis galbana plus different concentrations of ash particles (30, 90 and 150 mg L-1). The objective was to determine the cellular, physiological and anatomical responses. Mortality increased with ash concentrations, while feeding and respiration rates, tissue weight, and condition index decreased. The gills showed severe degradation of cilia and the presence of large mucous aggregates of cilia and ash. An increase in ash resulted in decreased lipid peroxidation and protein carbonyls, but increased total antioxidant capacity and phenols. Thus, volcanic ash particles may exert a high impact at both cellular and physiological levels for C. peruviana, where inhibition of gill function reduces the ability to acquire food.

HIV/AIDS infection in critical care: epidemiological profile and risk factors for mortality in a Colombian cohort.

INTRODUCTION: Outcomes of human immunodeficiency virus (HIV) infected patients admitted to intensive care units (ICU) have improved with antiretroviral therapy (ART). However, whether the outcomes have improved in low- and middle-income countries, paralleling those of high-income countries is unknown. The objective of this study was to describe a cohort of HIV-infected patients admitted to ICU in a middle-income country and identify the risk factors associated with mortality. METHODOLOGY: A cohort study of HIV-infected patients admitted to five ICUs in Medellín, Colombia, between 2009 and 2014 was done. The association of demographic, clinical and laboratory variables with mortality was analyzed using a Poisson regression model with random effects. RESULTS: During this time period, 472 admissions of 453 HIV-infected patients were included. Indications for ICU admission were: respiratory failure (57%), sepsis/septic shock (30%) and central nervous system (CNS) compromise (27%). Opportunistic infections (OI) explained 80% of ICU admissions. Mortality rate was 49%. Factors associated with mortality included hematological malignancies, CNS compromise, respiratory failure, and APACHE II score ≥ 20. CONCLUSIONS: Despite advances in HIV care in the ART era, half of HIV-infected patients admitted to the ICU died. This elevated mortality was associated to underlying disease severity (respiratory failure and APACHE II score ≥ 20), and host conditions (hematological malignancies, admission for CNS compromise). Despite the high prevalence of OIs in this cohort, mortality was not directly associated to OIs.

Comparison of gastric reactance with commonly used perfusion markers in a swine hypovolemic shock model.

BACKGROUND: The gut has been hypothesized to be a protagonist tissue in multiple organ dysfunction syndrome (MODS) for the past three decades. Gastric reactance (XL) is a potential perfusion marker derived from gastric impedance spectroscopy (GIS), which is an emerging tool through which living tissue can be continuously measured to determine its pathophysiological evolution. This study aimed to compare the performance of XL [positive predictive values (PPV), negative predictive values (NPV), and area under the curve (AUC)] against commonly used perfusion markers before and during hypovolemic shock in swine subjects. METHODS: Prospective, controlled animal trial with two groups, control group (CG) N = 5 and shock (MAP ≤ 48 mmHg) group (SG) N = 16. Comparison time points were defined as T-2 (2 h before shock), T-1 (1 h before shock), T0 (shock), T1 (1 h after shock), and T2 (2 h after shock). Shock severity was assessed through blood gases, systemic and hemodynamic variables, and via histological examination for assessing inflammation-edema and detachment in the gastric mucosa. Macroscopic assessment of the gastric mucosa was defined in five levels (0-normal mucosa, 1-stippling or epithelial hemorrhage, 2-pale mucosa, 3-violet mucosa, and 4-marmoreal mucosa). Receiver Operating Characteristic (ROC) curves of perfusion markers and XL were calculated to identify optimal cutoff values and their individual ability to predict hypovolemic shock. RESULTS: Comparison among the CG and the SG showed statistically significant differences in XL measurements at T-1, T0, T1, and T2, while lactate showed statistically significant differences until T1 and T2. Statistically significant differences were detected in mucosa class (p < 0.001) and in inflammation-edema in the gastric body and the fundus (p = 0.021 and p = 0.043). The performance of the minimum XL value per subject  per event (XL_Min) was better (0.81 ≤ AUC ≤ 0.96, 0.93 ≤ PPV ≤ 1.00, 0.45 ≤ NPV ≤ 0.83) than maximum lactate value (Lac_Max) per subject per event (0.29 ≤ AUC ≤ 0.82, 0.82 ≤ PPV ≤ 0.91, 0.24 ≤ NPV ≤ 0.82). Cutoff values for XL_Min show progressive increases at each time point, while cutoff values for Lac_Max increase only at T2. CONCLUSIONS: XL proved to be an indirect and consistent marker of inadequate gastric mucosal perfusion, which shows significant and detectable changes before commonly used markers of global perfusion under the hypovolemic shock conditions outlined in this work.

Adverse events in critical care: Search and active detection through the Trigger Tool.

AIM: To investigate the incidence of disadvantageous events by using the Global Trigger Tool in an intensive care unit (ICU). METHODS: A retrospective descriptive study was performed in a 12-bed university ICU in the city of Medellin, Colombia. Clinical charts of hospitalized patients were reviewed, between January 1 and December 31, 2016, with the following inclusion criteria: subjects aged over 18 years, with at least 24 h of hospitalization and who had a complete medical history that could be accessed. Interventions: Trained reviewers conducted a retrospective examination of medical charts searching for clue events that elicit investigation, in order to detect an unfavorable event. Measurements: Information was processed through SPSS software version 21; for numerical variables, the mean was reported with standard deviation (SD). Percentages were calculated for qualitative variables. RESULTS: Two hundred and forty-four triggers occurred, with 82.4% of subjects having presented with at least one and an average of 3.37 (SD 3.47). A total of 178 adverse events (AEs) took place in 48 individuals, with an incidence of 52.1%. On average, four events per patient were recorded, and for each unfortunate event, 1.98 triggers were presented. The most frequent displeasing issues were: pressure ulcers (17.6%), followed by complications or reactions to medical devices (4.3%), and lacerations or skin defects (3.7%); the least frequent was delayed diagnosis or treatment (0.56%). Thirty-eight point four percent of mishap events caused temporary damage that required intervention, and 48.9% of AEs were preventable. Comparison between AEs and admission diagnoses found that hypertension and sepsis were the only diagnoses that had statistical significance (P = 0.042 and 0.022, respectively). CONCLUSION: Almost half of the unfavorable issues were classified as avoidable, which leaves a very wide field of work in terms of preventative activities.

Thermoconformity strategy in the freshwater turtle Hydromedusa tectifera (Testudines, Chelidae) in its southern distribution area.

Ectotherm species are not capable of generating metabolic heat; therefore, they present different strategies for regulating their body temperatures, ranging from a precise degree of thermoregulation to a passive thermoconformity with ambient temperatures. In reptiles, aerial basking is the most common mechanism for gaining heat. However, among aquatic reptiles, such as freshwater turtles, aquatic basking is also frequent. Hydromedusa tectifera is a turtle of exclusively aquatic and nocturnal habits widely distributed in South America. We studied the relationship between body temperature (Tb) of H. tectifera and its habitat, and explored the effects of sex, life stage and body size and mass on Tb. Fieldwork was conducted in two streams of a mountain area of central Argentina. We recorded cloacal temperature, size and mass of 84 turtles. We also determined individuals' sex and life stage (adult/juvenile). Regarding ambient temperatures, we measured water temperature on the surface (Tsurf) and at depth of turtle capture (Tdepth) and air temperature. Mean Tb was 18.58°C (Min = 10.20°C; Max = 25.70°C). Tsurf and Tdepth were highly correlated. Multi-model analysis using Akaike criterion indicated that Tb was strongly associated with water temperature, whereas air temperature and body size and mass did not show a significant effect. There was also no effect of turtle sex or life stage on Tb. Our results indicate that H. tectifera is a thermoconformer and eurythermal species. A nocturnal pattern of activity and a fully aquatic lifestyle are suggested as determinant factors.

Implications of observed PBDE diffusion coefficients in low density polyethylene and silicone rubber.

A film-stacking technique was used to estimate diffusion coefficients of polybrominated diphenyl ethers (PBDEs) in low density polyethylene (LDPE) and silicone rubber. Substantially higher PBDE diffusion coefficients were observed for silicone rubber (AlteSil™) than for LDPE. A much steeper decrease in LDPE diffusion coefficients was found with increasing PBDE molecular weight than that for silicone rubber. From a passive sampling point-of-view, this means that for equivalent polymer-water partition coefficients for these two materials, the mass transfer resistance for these substances in the LDPE will be significantly higher than that for silicone rubber. Boundary layer control of the uptake process for silicone rubber can be expected for PBDEs. With a microplastic perspective, the low diffusion coefficients of PBDEs and in particular of decabromo diphenyl ether (BDE 209) in LDPE imply that the polymer diffusion coefficients for these plastic additives used as flame retardants need to be taken into account when considering the risk posed by microplastic particle ingestion by marine organisms.

Assessment of candidemia-attributable mortality in critically ill patients using propensity score matching analysis.

INTRODUCTION: Candidemia in critically ill patients is usually a severe and life-threatening condition with a high crude mortality. Very few studies have focused on the impact of candidemia on ICU patient outcome and attributable mortality still remains controversial. This study was carried out to determine the attributable mortality of ICU-acquired candidemia in critically ill patients using propensity score matching analysis. METHODS: A prospective observational study was conducted of all consecutive non-neutropenic adult patients admitted for at least seven days to 36 ICUs in Spain, France, and Argentina between April 2006 and June 2007. The probability of developing candidemia was estimated using a multivariate logistic regression model. Each patient with ICU-acquired candidemia was matched with two control patients with the nearest available Mahalanobis metric matching within the calipers defined by the propensity score. Standardized differences tests (SDT) for each variable before and after matching were calculated. Attributable mortality was determined by a modified Poisson regression model adjusted by those variables that still presented certain misalignments defined as a SDT > 10%. RESULTS: Thirty-eight candidemias were diagnosed in 1,107 patients (34.3 episodes/1,000 ICU patients). Patients with and without candidemia had an ICU crude mortality of 52.6% versus 20.6% (P < 0.001) and a crude hospital mortality of 55.3% versus 29.6% (P = 0.01), respectively. In the propensity matched analysis, the corresponding figures were 51.4% versus 37.1% (P = 0.222) and 54.3% versus 50% (P = 0.680). After controlling residual confusion by the Poisson regression model, the relative risk (RR) of ICU- and hospital-attributable mortality from candidemia was RR 1.298 (95% confidence interval (CI) 0.88 to 1.98) and RR 1.096 (95% CI 0.68 to 1.69), respectively. CONCLUSIONS: ICU-acquired candidemia in critically ill patients is not associated with an increase in either ICU or hospital mortality.