Identification of Phyllosoma Larvae of the Lobsters Acantharctus and Biarctus (Crustacea: Scyllaridae) from the SW Indian Ocean.

The accurate assignment of cryptic larvae to species-level is a key aspect of marine ecological research and can be achieved through integrated molecular and morphological studies. A combination of two mitochondrial markers (COI and 16S) and a detailed morphological analysis was used to identify phyllosoma larvae of slipper lobster (Scyllaridae) species collected during a survey in the SW Indian Ocean. Two morphotypes were tentatively assigned to Acantharctus ornatus and Biarctus pumilus, both genera for which the larval morphology was unknown. Morphological revision of an adult specimen used to generate the putative A. ornatus sequences in GenBank revealed that it was misidentified and corresponds to B. dubius. The final phyllosoma stage of B. pumilus and subfinal and final stages of A. ornatus were described, clarifying prior misidentifications in the literature. Scyllarid biodiversity in the SW Indian Ocean is underestimated and sampling of deeper water layers is recommended to complete current knowledge of species and larval stages present in the region.

Metabarcoding of ichthyoplankton communities associated with a highly dynamic shelf region of the southwest Indian Ocean.

Drifting fish eggs and larvae (ichthyoplankton) can be identified to species using DNA metabarcoding, thus allowing for post hoc community analyses at a high taxonomic resolution. We undertook a regional-scale study of ichthyoplankton distribution along the east coast of South Africa, focused on the contrasting environments of the tropical Delagoa and subtropical Natal Ecoregions, and on exposed and sheltered shelf areas. Zooplankton samples were collected with tow nets at discrete stations along cross-shelf transects (20-200 m depth) spaced along a latitudinal gradient that incorporates a known biogeographical boundary. Metabarcoding detected 67 fish species, of which 64 matched prior distribution records of fishes from South Africa, with the remaining three known from the Western Indian Ocean. Coastal, neritic and oceanic species were present, from epi- and mesopelagic to benthopelagic and benthic adult habitats. By family, Myctophidae (10 species), Carangidae, Clupeidae, Labridae (each with 4 species) and Haemulidae (3 species) were most speciose. Ichthyoplankton community composition varied significantly with latitude, distance to coast, and distance to the shelf edge. Small pelagic fishes had the highest frequency of occurrence: Engraulis capensis, Emmelichthys nitidus and Benthosema pterotum increased in frequency towards the north, whereas Etrumeus whiteheadi increased towards the south. Chub mackerel Scomber japonicus accounted for most variability related to distance from the coast, whilst African scad Trachurus delagoa correlated with distance to the shelf edge. Dissimilarity between communities in the Delagoa and Natal Ecoregions was 98-100%, whereas neighbouring transects located within the sheltered KwaZulu-Natal Bight had lower dissimilarity (56-86%). Onshore transport of ichthyoplankton by Agulhas Current intrusions plausibly explained the abundance of mesopelagic species over the shelf. Metabarcoding followed by community analysis revealed a latitudinal gradient in the ichthyoplankton, associations with coastal and shelf-edge processes, and evidence of a spawning area in the sheltered KwaZulu-Natal Bight.

Metabarcoding analysis of marine zooplankton confirms the ecological role of a sheltered bight along an exposed continental shelf.

Zooplankton plays an essential role in marine ecosystems as the link between primary producers (phytoplankton) and higher trophic levels in food webs, and as a dynamic pool of recruits for invertebrates and fish. Zooplankton communities are diverse with a patchy distribution at different spatial scales, influenced by oceanographic processes. The continental shelf of eastern South Africa is narrow and exposed to the western-boundary Agulhas Current, with some shelter against strong directional flow provided by the broader KwaZulu-Natal Bight, a coastal offset adjacent to an estuary. We compared zooplankton species richness, diversity and relative abundance of key taxa among sheltered and exposed shelf areas using metabarcoding and community analysis, to explore the ecological role of the bight in a highly dynamic ocean region. Metabarcoding recovered higher richness and diversity at a finer resolution than could previously be achieved with traditional microscopy. Of 271 operational taxonomic units (OTUs) recovered through metabarcoding, 63% could be matched with >95% sequence similarity to reference barcodes. OTUs were dominated by malacostracan crustaceans (161 spp.), ray-finned fishes (45 spp.) and copepods (28 spp.). Species richness, diversity and the relative abundance of key taxa differed between sheltered and exposed shelf areas. Lower species richness in the bight was partly attributed to structurally homogeneous benthic habitats, and an associated reduction of meroplanktonic species originating from local benthic-pelagic exchange. High relative abundance of a ray-finned fish in the bight, as observed based on fish eggs and read counts, confirmed that the bight is an important fish spawning area. Overall, zooplankton metabarcoding outputs were congruent with findings of previous ecological research using more traditional methods of observation.

Experimental validation of taxon-specific mini-barcode primers for metabarcoding of zooplankton.

Metabarcoding to determine the species composition and diversity of marine zooplankton communities is a fast-developing field in which the standardization of methods is yet to be fully achieved. The selection of genetic markers and primer choice are particularly important because they substantially influence species detection rates and accuracy. Validation is therefore an important step in the design of metabarcoding protocols. We developed taxon-specific mini-barcode primers for the cytochrome c oxidase subunit I (COI) gene region and used an experimental approach to test species detection rates and primer accuracy of the newly designed primers for prawns, shrimps and crabs and published primers for marine lobsters and fish. Artificially assembled mock communities (with known species ratios) and unsorted coastal tow-net zooplankton samples were sequenced and the detected species were compared with those seeded in mock communities to test detection rates. Taxon-specific primers increased detection rates of target taxa compared with a universal primer set. Primer cocktails (multiple primer sets) significantly increased species detection rates compared with single primer pairs and could detect up to 100% of underrepresented target taxa in mock communities. Taxon-specific primers recovered fewer false-positive or false-negative results than the universal primer. The methods used to design taxon-specific mini-barcodes and the experimental mock community validation protocols shown here can easily be applied to studies on other groups and will allow for a level of standardization among studies undertaken in different ecosystems or geographic locations.

Shark discards in selective and mixed-species pelagic longline fisheries.

The conservation status of several pelagic shark species is considered vulnerable with declining populations, yet data on shark fishing mortality remain limited for large ocean regions. Pelagic sharks are increasingly retained by mixed-species fisheries, or are discarded and not reported by selective fisheries for tunas (Thunnus spp.) or swordfish (Xiphias gladius). We estimated the fishing mortality of sharks (landings plus discard mortalities) in a South African-flagged pelagic longline fishery with diverse targeting and discard behaviour. A hierarchical cluster analysis was used to stratify the fleet according to the relative proportions of tunas, swordfish, blue sharks (Prionace glauca) and shortfin mako sharks (Isurus oxyrinchus) landed by individual vessels between 2013 and 2015. A spatial analysis of logbook data indicated that subfleets operated in distinct fishing areas, with overlap. Approximately 5% of all commercial longlines set during 2015 were sampled by a fisheries-independent observer, and the species, discard ratios and physical condition at discard of 6 019 captured sharks were recorded. Blue sharks and shortfin makos dominated observed shark catches, which were comprised of nine species and two species groups. Some 47% of observed sharks were retained and 20% were discarded in good physical condition. Only 4% of shortfin makos were discarded, compared to 68% of blue sharks. Blue shark discard mortality rates were twice as high as published at-vessel mortality rates, suggesting that onboard handling, among other factors, contributed to discard mortalities. Extrapolation to total fishing effort indicated a near 10-fold increase in blue shark and shortfin mako fishing mortality compared to an earlier study (1998-2005). Escalating shortfin mako fishing mortality was attributed to increased targeting to supply higher market demand. Discarding of blue sharks by selective fishing for tunas and swordfish had a greater impact on their fishing mortality than retention by shark-directed fleets. Higher levels of observer sampling are required to increase confidence in discard ratio estimates.

Myocardial Function during Low versus Intermediate Tidal Volume Ventilation in Patients without Acute Respiratory Distress Syndrome.

BACKGROUND: Mechanical ventilation with low tidal volumes has the potential to mitigate ventilation-induced lung injury, yet the clinical effect of tidal volume size on myocardial function has not been clarified. This cross-sectional study investigated whether low tidal volume ventilation has beneficial effects on myocardial systolic and diastolic function compared to intermediate tidal volume ventilation. METHODS: Forty-two mechanically ventilated patients without acute respiratory distress syndrome (ARDS) underwent transthoracic echocardiography after more than 24 h of mechanical ventilation according to the Protective Ventilation in Patients without ARDS (PReVENT) trial comparing a low versus intermediate tidal volume strategy. The primary outcome was left ventricular and right ventricular myocardial performance index as measure for combined systolic and diastolic function, with lower values indicating better myocardial function and a right ventricular myocardial performance index greater than 0.54 regarded as the abnormality threshold. Secondary outcomes included specific systolic and diastolic parameters. RESULTS: One patient was excluded due to insufficient acoustic windows, leaving 21 patients receiving low tidal volumes with a tidal volume size (mean ± SD) of 6.5 ± 1.8 ml/kg predicted body weight, while 20 patients were subjected to intermediate tidal volumes receiving a tidal volume size of 9.5 ± 1.6 ml/kg predicted body weight (mean difference, -3.0 ml/kg; 95% CI, -4.1 to -2.0; P < 0.001). Right ventricular dysfunction was reduced in the low tidal volume group compared to the intermediate tidal volume group (myocardial performance index, 0.41 ± 0.13 vs. 0.64 ± 0.15; mean difference, -0.23; 95% CI, -0.32 to -0.14; P < 0.001) as was left ventricular dysfunction (myocardial performance index, 0.50 ± 0.17 vs. 0.63 ± 0.19; mean difference, -0.13; 95% CI, -0.24 to -0.01; P = 0.030). Similarly, most systolic parameters were superior in the low tidal volume group compared to the intermediate tidal volume group, yet diastolic parameters did not differ between both groups. CONCLUSIONS: In patients without ARDS, intermediate tidal volume ventilation decreased left ventricular and right ventricular systolic function compared to low tidal volume ventilation, although without an effect on diastolic function.

Genetic structure and life history are key factors in species distribution models of spiny lobsters.

AIM: We incorporated genetic structure and life history phase in species distribution models (SDMs) constructed for a widespread spiny lobster, to reveal local adaptations specific to individual subspecies and predict future range shifts under the RCP 8.5 climate change scenario. LOCATION: Indo-West Pacific. METHODS: MaxEnt was used to construct present-day SDMs for the spiny lobster Panulirus homarus and individually for the three genetically distinct subspecies of which it comprises. SDMs incorporated both sea surface and benthic (seafloor) climate layers to recreate discrete influences of these habitats during the drifting larval and benthic juvenile and adult life history phases. Principle component analysis (PCA) was used to infer environmental variables to which individual subspecies were adapted. SDM projections of present-day habitat suitability were compared with predictions for the year 2,100, under the RCP 8.5 climate change scenario. RESULTS: In the PCA, salinity best explained P. h. megasculptus habitat suitability, compared with current velocity in P. h. rubellus and sea surface temperature in P. h. homarus. Drifting and benthic life history phases were adapted to different combinations of sea surface and benthic environmental variables considered. Highly suitable habitats for benthic phases were spatially enveloped within more extensive sea surface habitats suitable for drifting larvae. SDMs predicted that present-day highly suitable habitats for P. homarus will decrease by the year 2,100. MAIN CONCLUSIONS: Incorporating genetic structure in SDMs showed that individual spiny lobster subspecies had unique adaptations, which could not be resolved in species-level models. The use of sea surface and benthic climate layers revealed the relative importance of environmental variables during drifting and benthic life history phases. SDMs that included genetic structure and life history were more informative in predictive models of climate change effects.

The design and testing of mini-barcode markers in marine lobsters.

Full-length mitochondrial cytochrome c oxidase I (COI) sequence information from lobster phyllosoma larvae can be difficult to obtain when DNA is degraded or fragmented. Primers that amplify smaller fragments are also more useful in metabarcoding studies. In this study, we developed and tested a method to design a taxon-specific mini-barcode primer set for marine lobsters. The shortest, most informative portion of the COI gene region was identified in silico, and a DNA barcode gap analysis was performed to assess its reliability as species diagnostic marker. Primers were designed, and cross-species amplification success was tested on DNA extracted from a taxonomic range of spiny-, clawed-, slipper- and blind lobsters. The mini-barcode primers successfully amplified both adult and phyllosoma COI fragments, and were able to successfully delimit all species analyzed. Previously published universal primer sets were also tested and sometimes failed to amplify COI from phyllosoma samples. The newly designed taxon-specific mini-barcode primers will increase the success rate of species identification in bulk environmental samples and add to the growing DNA metabarcoding toolkit.

Effects of inconsistent reporting, regulation changes and market demand on abundance indices of sharks caught by pelagic longliners off southern Africa.

The assumption of a proportional relationship between catch-per-unit-effort (CPUE) and the abundance of sharks caught by pelagic longliners is tenuous when based on fisher logbooks that report only retained specimens. Nevertheless, commercial logbooks and landings statistics are often the only data available for stock status assessments. Logbook data collected from local and foreign pelagic longline vessels operating in four areas off southern Africa between 2000 and 2015 were used to construct standardized CPUE indices for blue sharks Prionace glauca and shortfin makos Isurus oxyrinchus. Generalized linear mixed models were used to explore the effects of year, month, vessel, fleet and presence of an observer on blue shark and shortfin mako variability. Landing statistics and auxiliary information on the history of the fishery, regulation changes, and market factors were superimposed on the CPUE indices, to test hypotheses that they would influence CPUE trends. Indices in the West and Southwest (Atlantic) areas were elevated for both species, compared to the South and East (Indian Ocean). The scale of year-on-year CPUE increments, up to an order of magnitude for blue sharks, reflected occasional targeting and retention, interspersed with periods where blue sharks were not caught, or discarded and not reported. Increments were smaller for higher value shortfin makos, suggesting that indices were less affected by unreported discarding. CPUE indices and landings of both shark species have increased in recent years, suggesting increased importance as target species. Analysis of logbook data resulted in unreliable indicators of shark abundance, but when trends were interpreted in conjunction with landings data, disaggregated by area and month, and with hindsight of market demand and regulation changes, anomalies could be explained.

Seascape genetics of the spiny lobster Panulirus homarus in the Western Indian Ocean: Understanding how oceanographic features shape the genetic structure of species with high larval dispersal potential.

This study examines the fine-scale population genetic structure and phylogeography of the spiny lobster Panulirus homarus in the Western Indian Ocean. A seascape genetics approach was used to relate the observed genetic structure based on 21 microsatellite loci to ocean circulation patterns, and to determine the influence of latitude, sea surface temperature (SST), and ocean turbidity (KD490) on population-level processes. At a geospatial level, the genetic clusters recovered corresponded to three putative subspecies, P. h. rubellus from the SW Indian Ocean, P. h. megasculptus from the NW Indian Ocean, and P. h. homarus from the tropical region in-between. Virtual passive Lagrangian particles advected using satellite-derived ocean surface currents were used to simulate larval dispersal. In the SW Indian Ocean, the dispersion of particles tracked over a 4-month period provided insight into a steep genetic gradient observed at the Delagoa Bight, which separates P. h. rubellus and P. h. homarus. South of the contact zone, particles were advected southwestwards by prevailing boundary currents or were retained in nearshore eddies close to release locations. Some particles released in southeast Madagascar dispersed across the Mozambique Channel and reached the African shelf. Dispersal was characterized by high seasonal and inter-annual variability, and a large proportion of particles were dispersed far offshore and presumably lost. In the NW Indian Ocean, particles were retained within the Arabian Sea. Larval retention and self-recruitment in the Arabian Sea could explain the recent genetic divergence between P. h. megasculptus and P. h. homarus. Geographic distance and minimum SST were significantly associated with genetic differentiation in multivariate analysis, suggesting that larval tolerance to SST plays a role in shaping the population structure of P. homarus.

A molecular phylogeny of the spiny lobster Panulirus homarus highlights a separately evolving lineage from the Southwest Indian Ocean.

Accurate species description in the marine environment is critical for estimating biodiversity and identifying genetically distinct stocks. Analysis of molecular data can potentially improve species delimitations because they are easily generated and independent, and yield consistent results with high statistical power. We used classical phylogenetic (maximum likelihood and Bayesian inference) and coalescent-based methods (divergence dating with fossil calibrations and coalescent-based species delimitation) to resolve the phylogeny of the spiny lobster Panulirus homarus subspecies complex in the Indo-West Pacific. Analyses of mitochondrial data and combined nuclear and mitochondrial data recovered Panulirus homarus homarus and Panulirus homarus rubellus as separately evolving lineages, while the nuclear data trees were unresolved. Divergence dating analysis also identified Panulirus homarus homarus and Panulirus homarus rubellus as two distinct clades which diverged from a common ancestor during the Oligocene, approximately 26 million years ago. Species delimitation using coalescent-based methods corroborated these findings. A long pelagic larval life stage and the influence of ocean currents on post-larval settlement patterns suggest that a parapatric mode of speciation drives evolution in this subspecies complex. In combination, the results indicate that Panulirus homarus rubellus from the Southwest Indian Ocean is a separately evolving lineage and possibly a separate species.

Mortality as an endpoint in studies in critically ill patients: a reappraisal of definitions.

The recent literature was critically reviewed reporting heterogeneous mortality endpoints in studies involving critically ill patients. Both location- and duration-dependent definitions are used, more or less arbitrarily and sometimes with contradictory results. Location-dependent mortality refers to intensive care or in-hospital mortality whereas duration-dependent mortality concerns 7-180 day mortality after admission or intervention. There is no consensus on how mortality should be evaluated in the critically ill. It is argued that trialists should aim at uniformity in outcome evaluation of critical care, in order to allow comparison of studies, and that 28-day mortality should remain the primary endpoint for intervention studies.

Impact of Positive End-Expiratory Pressure on Thermodilution-Derived Right Ventricular Parameters in Mechanically Ventilated Critically Ill Patients.

OBJECTIVES: To examine the effect of positive end-expiratory pressure (PEEP) on right ventricular stroke volume variation (SVV), with possible implications for the number and timing of pulmonary artery catheter thermodilution measurements. DESIGN: Prospective, clinical pilot study. SETTING: Academic medical center. PARTICIPANTS: Patients who underwent volume-controlled mechanical ventilation and had a pulmonary artery catheter. INTERVENTION: PEEP was increased from 5-to-10 cmH2O and from 10-to-15 cmH2O with 10-minute intervals, with similar decreases in PEEP, from 15-to-10 cmH2O and 10-to-5 cmH2O. MEASUREMENTS AND MAIN RESULTS: In 15 patients, right ventricular parameters were measured using thermodilution at 10% intervals of the ventilatory cycle at each PEEP level with a rapid-response thermistor. Mean right ventricular stroke volume and end-diastolic volume declined during incremental PEEP and normalized on return to 5 cmH2O PEEP (p = 0.01 and p = 0.001, respectively). Right ventricular SVV remained unaltered by changes in PEEP (p = 0.26), regardless of incremental PEEP (p = 0.15) or decreased PEEP (p = 0.12). The coefficients of variation in the ventilatory cycle of all other thermodilution-derived right ventricular parameters also were unaffected by changes in PEEP. CONCLUSIONS: This study showed that increases in PEEP did not affect right ventricular SVV in critically ill patients undergoing mechanical ventilation despite reductions in mean right ventricular stroke volume and end-diastolic volume. This could be explained by cyclic counteracting changes in right ventricular preloading and afterloading during the ventilatory cycle, independent of PEEP. Changes in PEEP did not affect the number and timing of pulmonary artery catheter thermodilution measurements.

Safety and efficacy of amphotericin-B deoxycholate inhalation in critically ill patients with respiratory Candida spp. colonization: a retrospective analysis.

BACKGROUND: Candida spp. are frequently cultured from the respiratory tract in critically ill patients. Most intensivists start amphotericin-B deoxycholate (ABDC) inhalation therapy to eradicate Candida spp. from the respiratory tract. However, the safety and efficacy of this treatment are not well established. The purpose of this study was to assess the safety and efficacy of ABDC inhalation for the treatment of respiratory Candida spp. colonization in critically ill patients. METHODS: All non-neutropenic patients admitted into the intensive care unit (ICU) of a university hospital from December 2010-2011, who had positive Candida spp. cultures of the respiratory tract for more than 1 day and required mechanical ventilation >48 h were retrospectively included. The decision to start ABDC inhalation had been made by attending intensivists on clinical grounds in the context of selective decontamination of the digestive tract. Infection characteristics and patient courses were assessed. RESULTS: Hundred and thirteen consecutive patients were studied. Fifty-one of them received ABDC inhalation and their characteristics at baseline and day 1 of respiratory colonization did not differ from those of colonized patients not receiving treatment (n = 62). The ABDC-treated group had a similar Candida spp. load but did not decolonize more rapidly as compared to untreated patients. The clinical pulmonary infection and lung injury scores did not decrease as in the untreated group. In a Cox proportional hazard model, the duration of mechanical ventilation was increased (P < 0.003) by ABDC treatment independently of other potential determinants and Candida spp. colonization. No differences in ventilator-associated pneumonia or in overall mortality (up to day 90) were observed. CONCLUSION: Treatment of respiratory Candida spp. colonization in non-neutropenic critically ill patients by inhaled ABDC may not affect respiratory colonization but may increase duration of mechanical ventilation, because of direct toxicity of the drug on the lung.

Cardiac dysfunction after aneurysmal subarachnoid hemorrhage: relationship with outcome.

OBJECTIVE: To assess whether cardiac abnormalities after aneurysmal subarachnoid hemorrhage (aSAH) are associated with delayed cerebral ischemia (DCI) and clinical outcome, independent from known clinical risk factors for these outcomes. METHODS: In a prospective, multicenter cohort study, we performed echocardiography and ECG and measured biochemical markers for myocardial damage in patients with aSAH. Outcomes were DCI, death, and poor clinical outcome (death or dependency for activities of daily living) at 3 months. With multivariable Poisson regression analysis, we calculated risk ratios (RRs) with corresponding 95% confidence intervals. We used survival analysis to assess cumulative percentage of death in patients with and without echocardiographic wall motion abnormalities (WMAs). RESULTS: We included 301 patients with a mean age of 57 years; 70% were women. A wall motion score index ≥1.2 had an adjusted RR of 1.2 (0.9-1.6) for DCI, 1.9 (1.1-3.3) for death, and 1.8 (1.1-3.0) for poor outcome. Midventricular WMAs had adjusted RRs of 1.1 (0.8-1.4) for DCI, 2.3 (1.4-3.8) for death, and 2.2 (1.4-3.5) for poor outcome. For apical WMAs, adjusted RRs were 1.3 (1.1-1.7) for DCI, 1.5 (0.8-2.7) for death, and 1.4 (0.8-2.5) for poor outcome. Elevated troponin T levels, ST-segment changes, and low voltage on the admission ECGs had a univariable association with death but were not independent predictors for outcome. CONCLUSION: WMAs are independent risk factors for clinical outcome after aSAH. This relation is partly explained by a higher risk of DCI. Further study should aim at treatment strategies for these aSAH-related cardiac abnormalities to improve clinical outcome.

Pulse pressure variation does not reflect stroke volume variation in mechanically ventilated rats with lipopolysaccharide-induced pneumonia.

1. The present study examined the relationship between centrally measured stroke volume variation (SVV) and peripherally derived pulse pressure variation (PPV) in the setting of increased total arterial compliance (CA rt ). 2. Ten male Wistar rats were anaesthetized, paralysed and mechanically ventilated before being randomized to receive intrapulmonary lipopolysaccharide (LPS) or no LPS. Pulse pressure (PP) was derived from the left carotid artery, whereas stroke volume (SV) was measured directly in the left ventricle. Values of SVV and PPV were calculated over three breaths. Balloon inflation of a catheter positioned in the inferior vena cava was used, for a maximum of 30 s, to decrease preload while the SVV and PPV measurements were repeated. Values of CA rt were calculated as SV/PP. 3. Intrapulmonary LPS increased CA rt and SV. Values of SVV and PPV increased in both LPS-treated and untreated rats during balloon inflation. There was a correlation between SVV and PPV in untreated rats before (r = 0.55; P = 0.005) and during (r = 0.69; P < 0.001) occlusion of the vena cava. There was no such correlation in LPS-treated rats either before (r = -0.08; P = 0.70) or during (r = 0.36; P = 0.08) vena cava occlusion. 4. In conclusion, under normovolaemic and hypovolaemic conditions, PPV does not reflect SVV during an increase in CA rt following LPS-induced pneumonia in mechanically ventilated rats. Our data caution against their interchangeability in human sepsis.

Incidence and prognosis of dysnatraemia in critically ill patients: analysis of a large prevalence study.

BACKGROUND: The objective of this study is to assess the impact of dysnatraemia on mortality among intensive care unit (ICU) patients in a large, international cohort. MATERIAL AND METHODS: Analysis of the Extended Prevalence of Infection in Intensive Care (EPIC II) study, a 1-day (8 May 2007) worldwide multicenter, prospective point prevalence study. Hyponatraemia was categorized as mild (130-134 mM/L), moderate (125-129 mM/L) or severe (< 125 mM/L). Hypernatraemia was also categorized as mild (146-150 mM/L), moderate (151-155 mM/L) or severe (> 155 mM/L). Patients with normal serum sodium (135-145 mM/L) constituted the reference group. The main outcome was hospital mortality. Analysis was conducted separately for patients admitted on the study day (25.8%) and those already present on the ICU (74.2%). RESULTS: Serum sodium was measured in 13 276 of the 13 796 patients (96.2%). A total of 3815 patients (28.7%) had dysnatraemia: 12.9% with hyponatraemia and 15.8% with hypernatraemia. The prevalence of dysnatraemia was significantly greater in patients already present on the ICU prior to the study day than for those just admitted (13.1% vs. 12.3% for hyponatraemia and 17.1% vs. 12.1% for hypernatraemia, both P < 0.001). Hospital mortality rates were higher in patients with dysnatraemia than in those with normal sodium levels and were directly related to the severity of hypo- and hypernatraemia. This association between dysnatraemia and mortality was similar in infected and noninfected patients (P = 0.061). CONCLUSIONS: Dysnatraemia is more frequent during the ICU stay than on the day of admission. Dysnatraemia in the ICU - even mild - is an independent predictor of increased hospital mortality.

Plasma NGAL similarly predicts acute kidney injury in sepsis and nonsepsis.

AIM: Plasma NGAL is released in sepsis irrespective of acute kidney injury (AKI). The current study investigated the effect of sepsis on the diagnostic value of NGAL for AKI. MATERIALS & METHODS: In 700 intensive care unit admissions, NGAL was measured at four time points (<24 h) following admission. RESULTS: In total, 663 admissions were included in the final analysis, of which 80 patients had sepsis (12%). AKI occurred in 22% of the patients without and 66% with sepsis. NGAL levels were higher in non-AKI patients with sepsis compared with non-AKI patients without sepsis at all time points (p = 0.03 or lower). In patients with AKI a similar difference was observed (p < 0.001). The area under the curve for AKI was unaffected by the presence of sepsis (0.76 in sepsis vs 0.78 in nonsepsis; p = 0.72); however, the optimal test cutoff values were higher in the former. CONCLUSION: Sepsis enhances the production of plasma NGAL in critically ill adult patients irrespective of the presence of AKI. However, the diagnostic test accuracy for AKI is unaffected by sepsis, although optimal cutoff values are elevated.

Predicting outcome of rethoracotomy for suspected pericardial tamponade following cardio-thoracic surgery in the intensive care unit.

OBJECTIVES: Pericardial tamponade after cardiac surgery is difficult to diagnose, thereby rendering timing of rethoracotomy hard. We aimed at identifying factors predicting the outcome of surgery for suspected tamponade after cardio-thoracic surgery, in the intensive care unit (ICU). METHODS: Twenty-one consecutive patients undergoing rethoracotomy for suspected pericardial tamponade in the ICU, admitted after primary cardio-thoracic surgery, were identified for this retrospective study. We compared patients with or without a decrease in severe haemodynamic compromise after rethoracotomy, according to the cardiovascular component of the sequential organ failure assessment (SOFA) score. RESULTS: A favourable haemodynamic response to rethoracotomy was observed in 11 (52%) of patients and characterized by an increase in cardiac output, and less fluid and norepinephrine requirements. Prior to surgery, the absence of treatment by heparin, a minimum cardiac index < 1.0 L/min/m2 and a positive fluid balance (> 4,683 mL) were predictive of a beneficial haemodynamic response. During surgery, the evacuation of clots and > 500 mL of pericardial fluid was associated with a beneficial haemodynamic response. Echocardiographic parameters were of limited help in predicting the postoperative course, even though 9 of 13 pericardial clots found at surgery were detected preoperatively. CONCLUSION: Clots and fluids in the pericardial space causing regional tamponade and responding to surgical evacuation after primary cardio-thoracic surgery, are difficult to diagnose preoperatively, by clinical, haemodynamic and even echocardiographic evaluation in the ICU. Only absence of heparin treatment, a large positive fluid balance and low cardiac index predicted a favourable haemodynamic response to rethoracotomy. These data might help in deciding and timing of reinterventions after primary cardio-thoracic surgery.