A prospective randomised multi-centre controlled trial on tight glucose control by intensive insulin therapy in adult intensive care units: the Glucontrol study

PURPOSE

An optimal target for glucose control in ICU patients remains unclear. This prospective randomized controlled trial compared the effects on ICU mortality of intensive insulin therapy (IIT) with an intermediate glucose control.

METHODS

Adult patients admitted to the 21 participating medico-surgical ICUs were randomized to group 1 (target BG 7.8-10.0 mmol/L) or to group 2 (target BG 4.4-6.1 mmol/L).

RESULTS

While the required sample size was 1,750 per group, the trial was stopped early due to a high rate of unintended protocol violations. From 1,101 admissions, the outcomes of 542 patients assigned to group 1 and 536 of group 2 were analysed. The groups were well balanced. BG levels averaged in group 1 8.0 mmol/L (IQR 7.1-9.0) (median of all values) and 7.7 mmol/L (IQR 6.7-8.8) (median of morning BG) versus 6.5 mmol/L (IQR 6.0-7.2) and 6.1 mmol/L (IQR 5.5-6.8) for group 2 (p < 0.0001 for both comparisons). The percentage of patients treated with insulin averaged 66.2 and 96.3%, respectively. Proportion of time spent in target BG was similar, averaging 39.5% and 45.1% (median (IQR) 34.3 (18.5-50.0) and 39.3 (26.2-53.6)%) in the groups 1 and 2, respectively. The rate of hypoglycaemia was higher in the group 2 (8.7%) than in group 1 (2.7%, p < 0.0001). ICU mortality was similar in the two groups (15.3 vs. 17.2%).

CONCLUSIONS

In this prematurely stopped and therefore underpowered study, there was a lack of clinical benefit of intensive insulin therapy (target 4.4-6.1 mmol/L), associated with an increased incidence of hypoglycaemia, as compared to a 7.8-10.0 mmol/L target. (ClinicalTrials.gov # NCT00107601, EUDRA-CT Number: 200400391440).

High tidal volume and positive fluid balance are associated with worse outcome in acute lung injury

STUDY OBJECTIVES

Recent data have suggested that ventilatory strategy could influence outcomes from acute lung injury (ALI) and ARDS. We tested the hypothesis that infection/sepsis and use of higher tidal volumes than those applied in the ARDS Network (ARDSnet) study (> 7.4 mL/kg of predicted body weight) would worsen outcome in patients with ALI/ARDS.

DESIGN

International cohort, observational study.

SETTING

One hundred ninety-eight European ICUs participating in the Sepsis Occurrence in Acutely Ill Patients study.

PATIENTS OR PARTICIPANTS

All 3,147 adult patients admitted to one of the participating ICUs between May 1, 2002, and May 15, 2002.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Patients were followed up until death, hospital discharge, or for 60 days. Of the 3,147 patients, 393 patients (12.5%) had ALI/ARDS. ICU and hospital mortality was higher in patients with ALI/ARDS than those without ALI/ARDS (38.9% vs 15.6% and 45.5% vs 21.0%, respectively; p < 0.001). A multivariable logistic regression analysis with ICU outcome as the dependent factor showed that the independent risks for mortality were as follows: presence of cancer, use of tidal volumes higher than those used by the ARDSnet study, degree of multiorgan dysfunction, and higher mean fluid balance. Sepsis, septic shock, and oxygenation at the onset of ALI/ARDS were not independently associated with higher mortality rates.

CONCLUSIONS

In addition to comorbidities and organ dysfunction, high tidal volumes and positive fluid balance are associated with a worse outcome from ALI/ARDS.

Obesity is associated with increased morbidity but not mortality in critically ill patients

OBJECTIVE

To investigate the possible impact of obesity on morbidity and mortality in intensive care unit (ICU) patients included in the European observational sepsis occurrence in acutely ill patients (SOAP) study.

DESIGN

Planned substudy from the SOAP database.

SETTING

One hundred and ninety-eight ICUs in 24 European countries.

PATIENTS

All patients admitted to one of the participating ICUs. Patients were classified, according to their body mass index (BMI), as underweight (<18.5 kg/m(2)), normal weight (18.5-24.9 kg/m(2)), overweight (25-29.9 kg/m(2)), obese (30-39.9 kg/m(2)), and very obese (>or=40 kg/m(2)).

MEASUREMENTS AND RESULTS

The BMI was available in 2,878 (91%) of the 3,147 patients included in the SOAP study; 120 patients (4.2%) were underweight, 1,206 (41.9%) had a normal BMI, 1,047 (36.4%) were overweight, 424 (14.7%) were obese, and 81 (2.8%) were very obese. Obese and very obese patients more frequently developed ICU-acquired infections than patients in lower BMI categories. Very obese patients showed a trend towards longer ICU [median (IQ): 4.1 (1.8-12.1) vs. 3.1 (1.7-7.2) days, P = 0.056) and hospital lengths of stay [14.3 (8.4-27.4) vs. 12.3 (5.1-24.4), days P = 0.077] compared to those with a normal BMI. However, there were no significant differences among the groups in ICU or hospital mortality rates. In a multivariate Cox regression analysis, none of the BMI categories was associated with an increased risk of 60-day in-hospital death.

CONCLUSION

BMI did not have a significant impact on mortality in this mixed population of ICU patients.

Simultaneous determination of creatine compounds and adenine nucleotides in myocardial tissue by high-performance liquid chromatography

A rapid high-performance liquid chromatography method was developed for the determination of creatine phosphate, creatine, adenine nucleotides, and related compounds in myocardial tissue. Analysis was performed by reversed-phase chromatography on a C18 column containing 3-microns particles, employing gradient elution and uv detection at 210 nm. Separation was achieved in less than 5 min. Total analysis time, including equilibration of the column after return of the gradient to starting conditions, was 8 min. The high reproducibility and short analysis time make this method suitable for the routine analysis of large series of samples.

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.

Prediction of mortality in febrile medical patients: How useful are systemic inflammatory response syndrome and sepsis criteria?

STUDY OBJECTIVES

The aim was to evaluate demographic, clinical, and laboratory variables in febrile patients, with or without a microbiologically confirmed infection, for prediction of death, in comparison to the systemic inflammatory response syndrome (SIRS) and its criteria, such as abnormal temperature, tachycardia, tachypnea, and abnormal WBC count, and to sepsis, that includes SIRS and an infection.

DESIGN

A prospective cohort study.

SETTING

Department of internal medicine at a university hospital.

PATIENTS

In 300 consecutive, hospitalized medical patients with new onset of fever, demographic, clinical, and laboratory variables were obtained during the 2 days after inclusion, while microbiological results for a follow-up period of 7 days were collected. Patients were followed up for survival or death, up to a maximum of 28 days after inclusion.

MEASUREMENTS AND RESULTS

Of all patients, 95% had SIRS, 44% had sepsis with a microbiologically confirmed infection, and 9% died. A model with a set of variables all significantly (p<0.01) contributing to the prediction of mortality was derived. The set included the presence of hospital-acquired fever, the peak respiratory rate, the nadir score on the Glasgow coma scale, and the nadir albumin plasma level within the first 2 days after inclusion. This set of variables predicted mortality for febrile patients with microbiologically confirmed infection even better. The predictive values for mortality of SIRS and sepsis were less than that of our set of variables.

CONCLUSIONS

In comparison to SIRS and sepsis, the new set of variables predicted mortality better for all patients with fever and also for those with microbiologically confirmed infection only. This type of effort may help in refining definitions of SIRS and sepsis, based on prognostically important demographic, clinical, and laboratory variables that are easily obtainable at the bedside.

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.

ARDS of early or late onset: does it make a difference?

BACKGROUND

Differences in outcomes have been demonstrated for critically ill patients with late-onset compared with early-onset renal failure and late-onset compared with early-onset shock, which could cause a lead-time bias in clinical trials assessing potential therapies for these conditions. We used data from a large, multicenter observational study to assess whether late-onset ARDS was similarly associated with worse outcomes compared with early-onset ARDS.

METHODS

Data were extracted from the Sepsis Occurrence in Acutely Ill Patients (SOAP) study, which involved 198 ICUs from 24 European countries. All adult patients admitted to a participating ICU between May 1, 2002 and May 15, 2002, were eligible, except those admitted for uncomplicated postoperative surveillance. Early/late onset acute lung injury (ALI)/ARDS was defined as ALI/ARDS occurring within/after 48 h of ICU admission.

RESULTS

Of the 3,147 patients included in the SOAP study, 393 (12.5%) had a diagnosis of ALI/ARDS; 254 had early-onset ALI/ARDS (64.6%), and 139 (35.5%) late-onset. Patients with early-onset ALI/ARDS had higher Simplified Acute Physiology II scores on admission and higher initial Sequential Organ Failure Assessment scores. Patients with late-onset ALI/ARDS had longer ICU and hospital lengths of stay than patients with early-onset ALI/ARDS. ICU and hospital mortality rates were, if anything, lower in late-onset ALI/ARDS than in early-onset ALI/ARDS, but these differences were not statistically significant.

CONCLUSIONS

There were no significant differences in mortality rates between early- and late-onset ARDS, but patients with late-onset ALI/ARDS had longer ICU and hospital lengths of stay.

Molecular phylogeny of the spiny lobster genus Palinurus (Decapoda: Palinuridae) with hypotheses on speciation in the NE Atlantic/Mediterranean and SW Indian Ocean

Sequence data derived from the mitochondrial DNA 16S rRNA and COI genes were used to determine the phylogenetic relationships among six Palinurus spiny lobster species. Three species (P. charlestoni, P. elephas, and P. mauritanicus) occur in the northeastern Atlantic/Mediterranean, and the others (P. barbarae, P. delagoae and P. gilchristi) inhabit the southwestern Indian Ocean. Parsimony and model based phylogenetics strongly supported the monophyly of the genus. A combined parsimony analysis based on 1001bp and 274 parsimony informative characters recovered the most resolved phylogeny with >70% bootstrap support for associations among species. The Atlantic P. charlestoni consistently clusters nested within the Indian Ocean clade, and the mtDNA sequence divergence between the two most distant species is 8.24%. If the northward collision of Africa with Eurasia in the Miocene caused the final physical separation between the Atlantic and Indian Ocean taxa, then the Palinurus mtDNA (COI and 16S combined) evolved no faster than 0.18% (lower bound) to 0.36% (upper bound) per lineage per million years. The six extant species occur in the pathways of the North Atlantic and South Indian Ocean gyres, and hypotheses on their radiation are developed relative to the strengthening of boundary currents in the Miocene and life history traits congruent with survival in strong ocean currents.

Simulating the effects of different spatio-temporal fire regimes on plant metapopulation persistence in a Mediterranean-type region

Spatio-temporal fire regimes are likely to shift with changes in land use and climate. Such a shift in the disturbance regime has been proposed from recent reconstructions of the regional fire history in the Mediterranean-type woodlands and shrublands of Western Australia which suggest that fire was much more frequent before 1930 (local fire intervals of 3–5 years) than it is today (local fire intervals of 8–15 years).

To investigate the potential biodiversity consequences of such changes in fire regime for fire-killed woody species, we developed a spatial model for the serotinous shrub Banksia hookeriana that grows on sand dunes of the Eneabba Plain, Western Australia. We sought to identify the envelope of fire regimes under which the spatially separated populations in this species are able to persist, and whether this encompasses the fire regimes proposed by recent fire-history reconstructions.

We tested two fire frequency-size distribution scenarios: (1) a scenario where fire size depends on the spatial patch configuration; and (2) a scenario depending also on available fuel (time since last fire), which reduces fire size at short inter-fire intervals.

In scenario 1, metapopulation persistence was only likely for mean ignition intervals at the landscape scale of 6 years. In scenario 2, persistence was likely for the whole range of fire interval distributions at the landscape scale suggested by the empirical data. However, persistence was almost impossible if the mean return fire interval at the local scale (i.e. for individual dunes) is < 8 years.

Synthesis and applications. We have demonstrated that this plant metapopulation can potentially persist over a wide range of temporal fire regimes at the landscape scale, so long as there are buffering mechanisms at work (e.g. feedback between fire spread and vegetation age) which reduces the probability of large fires at short intervals. Our findings demonstrate that at least some parts of the landscape must burn substantially less frequently on average than suggested by the empirical fire reconstructions for the early and pre-European period if populations of fire-killed woody species such as B. hookeriana are to be conserved.

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.

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.

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.