Anees Sindi

Fluid Resuscitation in Sepsis: A Systematic Review and Network Meta-analysis

Resuscitation with crystalloids compared with colloids for critically ill patients has been evaluated in large randomized, controlled trials (16) and meta-analyses (713). One meta-analysis(10) including 74 trials reported no difference in mortality between critically ill patients resuscitated with crystalloids and albumin (relative risk [RR], 1.01 [95% CI, 0.93 to 1.10]), hydroxyethyl starch (HES) (RR, 1.10 [CI, 0.91 to 1.32]), gelatin (RR, 0.91 [CI, 0.49 to 1.72]), or dextran (RR, 1.24 [CI, 0.94 to 1.65]). Another meta-analysis (8) reported that resuscitation with an albumin-containing solution in patients with sepsis may decrease mortality compared with solutions containing no albumin (RR, 0.82 [CI, 0.67 to 1.00]). Recent evidence suggests that starches, compared with other fluids and regardless of molecular weight, may be associated with acute kidney injury in the general population of critically ill patients and in those with sepsis (5, 11, 1315). A recent large pragmatic trial comparing colloids (mostly starches) with crystalloids (mostly 0.9% sodium chloride) suggested a 90-day mortality benefit with colloids (RR, 0.92 [CI, 0.86 to 0.99]) (16). Crystalloids can be characterized on the basis of tonicity and electrolyte content. The presence of an organic anion (for example, lactate, acetate, or gluconate) and correspondingly lower chloride content that more closely resembles the composition of plasma suggest that a crystalloid is balanced (for example, Ringer lactate and acetate solutions) (17). The most commonly used crystalloid, normal saline (0.9% sodium chloride), is far from normal, with a pH much less than 7.0 and a supraphysiologic chloride content of 154 mmol/L (18, 19). Compared with a balanced crystalloid solution, normal saline predisposes patients to hyperchloremic metabolic acidosis, decreased renal blood flow to the glomerulus, and impaired smooth-muscle contractility (20). Investigators have not done randomized, controlled trials (RCTs) comparing balanced and unbalanced crystalloids. However, 1 large beforeafter study of critically ill patients showed that balanced versus unbalanced fluid solution was associated with a lower incidence of acute kidney injury (8.4% vs. 14%; P< 0.01) and renal replacement therapy (6.3% vs. 10%; P= 0.05) but no differences in hospital mortality (18). Colloids include natural compounds, such as albumin, and synthetic compounds of HES, gelatin, or dextran. Expansion of plasma volume increases in proportion to the osmotic or oncotic potential, and colloids theoretically require less volume than crystalloids to achieve equivalent hemodynamic effect (19). Limitations of colloids include development of acute kidney injury and coagulation disorders with starches (14) and albumin creates risk for exposure to blood products (19). Another important consideration is the biochemical properties of the crystalloid solution in which the colloid is dissolved. For example, the chloride concentrations in HES may vary between 154 mmol/L (Voluven, Fresenius Kabi) and 118 mmol/L (Tetraspan, B. Braun Medical) (21). Whether any of these fluid properties translate into a survival advantage remains unclear, particularly regarding the optimal fluid for resuscitation in patients with sepsis. Fluid resuscitation, in addition to antibiotics and source control, is a cornerstone of initial management of sepsis (22). However, fluid management in patients with sepsis varies widely in practice (16, 23, 24). Meta-analyses of fluid resuscitation have been limited by not focusing on patients with sepsis (7, 9, 10), not considering electrolyte composition (5, 8, 10, 11), considering only 2 or 3 categories of fluid (25), not including direct and indirect comparisons in the same model, and omission of recent large RCTs(35, 16). Therefore, we did a network meta-analysis (NMA) considering direct and indirect comparisons of all types of fluid resuscitation tested in RCTs in patients with severe sepsis and septic shock, focusing on the effect of these interventions on mortality. Methods Data Sources and Searches This review was done using a predefined protocol. Initially, we searched MEDLINE (1948 to December 2012), EMBASE (1980 to December 2012), ACP Journal Club (1991 to December 2012), the Cochrane Central Register of Controlled Trials, HealthSTAR, the Allied and Complementary Medicine Database, and CINAHL. We updated the MEDLINE and EMBASE searches in August 2013 and March 2014. We screened previously published meta-analyses for relevant citations. Supplement 1 presents the search terms used. Supplement 1. WinBUGS Code for NMA Six reviewers working in 3 pairs screened the titles and abstracts to determine potential eligibility, and entries identified by any reviewer proceeded to the full-text eligibility review. Pretested eligibility forms were used for full-text review, which was also done in duplicate. A third adjudicator helped to resolve disagreements through consensus. Study Selection We selected parallel-group RCTs, including factorial designs, but excluded quasi-randomized and crossover trials. We excluded all studies published by Dr. Joachim Boldt because of suspected lack of integrity (26, 27). We did not apply restrictions on language or publication date. We included studies that involved adult (aged 16 years) critically ill patients with severe sepsis or septic shock as defined by the investigators and who required fluid resuscitation (defined as the administration of a bolus of intravenous fluid exceeding the amount required for maintenance or replacement fluids). We included studies with mixed critically ill populations whenever separate data for patients with sepsis were available. We excluded studies in which most patients had the systemic inflammatory response syndrome secondary to other causes (such as burn, pancreatitis, and trauma) without a clear sepsis subgroup and those focusing on patients after elective surgery. Interventions studied included any fluid or fluid strategy used for resuscitation compared with another fluid or fluid strategy. We excluded studies in which the primary goal was to assess short-term hemodynamic response. Our outcome was 90-day mortality or, if not available, 30-day, intensive care unit, or hospital mortality, whichever was longest. Data Extraction Pairs from the same 6 reviewers abstracted data in duplicate. Another clinician reviewed disagreements, and consensus was reached by discussion. We contacted authors of primary publications for missing or unclear information. Risk of Bias Independently and in duplicate, reviewers assessed risk of bias using a modified version of the Cochrane Collaboration assessment tool (28, 29). We judged each included study as having low, probably low, probably high, or high risk of bias for randomization-sequence generation, randomization concealment, blinding, incomplete data, selective reporting, and free of other bias (including intention-to-treat analysis). The overall rating of risk of bias for each study was the lowest rating for any of the criteria (Appendix Table). Appendix Table. Risk of Bias, by Study Data Synthesis and Analysis Our analysis classified fluids as crystalloids (divided into balanced and unbalanced solutions) and colloids (divided into albumin, gelatin, and low- and high-molecular-weight HES [threshold molecular weight, 150000 kDa]). We considered fluid balanced if it contained an anion of a weak acid (buffer) and its chloride content was correspondingly less than in 0.9% sodium chloride (21). The relevant analyses were a 4-node NMA (crystalloids vs. albumin vs. HES vs. gelatin), a 6-node NMA (crystalloids vs. albumin vs. HES vs. gelatin, with crystalloids divided into balanced or unbalanced and HES divided into low or high molecular weight), and a conventional direct frequentist fixed-effects meta-analytic comparison of crystalloids versus colloids. To calculate direct estimates of treatment effect for each pair of treatments in the 4- and 6-node networks, we did a frequentist fixed-effects meta-analysis. We reported the results as odds ratios (ORs) and corresponding 95% CIs. We evaluated heterogeneity by estimating the variance between studies (chi-square test and I 2 statistic) (30, 31). Using a Bayesian framework, we did 4- and 6-node fixed-effects NMAs for each treatment. We reported the results as ORs and corresponding 95% credibility intervals (CrIs), which are the Bayesian analogue of 95% CIs(32). The ORs reported are relative effects of compared fluids. The models are based on 80000 iterations with a burn-in of 40000 and a thin of 10. We used a random seed and vague priors. We assessed nonconvergence on the basis of BrooksGelmanRubin plots (33). We used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess confidence in estimates of effect (quality of evidence) associated with specific comparisons, including estimates from direct, indirect, and final NMAs (Supplement 2) (34). Our confidence assessment addressed risk of bias, incoherence, imprecision, inconsistency, indirectness, and publication bias. Supplement 2. GRADE Confidence Explanations for All Point Estimates The starting point for confidence in direct and indirect estimates was high. However, indirect estimates were potentially rated down for intransitivity (that is, differences in patients, co-interventions, or settings that could lead to effect modification and thus a misleading comparison of fluid management strategies). We inferred confidence in indirect estimates by examining the connecting loops associated with the particular comparison. The confidence rating chosen was the lowest of the direct estimates contributing to the indirect comparison. For example, consider a comparison of A versus B that is informed by comparisons of A versus C and B versus C. If A versus C was rated as high confidence and B versus C as moderate confidence, the overall indirect confidence rating was ini

The effect of selenium therapy on mortality in patients with sepsis syndrome: a systematic review and meta-analysis of randomized controlled trials.

Background:Patients with sepsis syndrome commonly have low serum selenium levels. Several randomized controlled trials have examined the efficacy of selenium supplementation on mortality in patients with sepsis. Objective:To determine the efficacy and safety of high-dose selenium supplementation compared to placebo for the reduction of mortality in patients with sepsis. Sources of Data:We searched Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, SciFinder, and Clinicaltrials.gov. Selection Criteria:Randomized controlled parallel group trials comparing selenium supplementation in doses greater than daily requirement to placebo on the outcome of mortality in patients with sepsis syndrome. Data Collection and Analysis:Two reviewers independently applied eligibility criteria, assessed quality, and extracted data. The primary outcome was mortality; secondary outcomes were ICU length of stay, nosocomial pneumonia, and adverse events. Trial authors were contacted for additional or clarifying information. Results:Nine trials enrolling a total of 792 patients were included. Selenium supplementation in comparison to placebo was associated with lower mortality (odds ratio, 0.73; 95% CI, 0.54, 0.98; p = 0.03; I2 = 0%). Among patients receiving and not receiving selenium, there was no difference in ICU length of stay (mean difference, 2.03; 95% CI, –0.51, 4.56; p = 0.12; I2 = 0%) or nosocomial pneumonia (odds ratio, 0.83; 95% CI, 0.28, 2.49; p = 0.74; I2 = 56%). Significant heterogeneity among trials in adverse event reporting precluded pooling of results. Conclusions:In patients with sepsis, selenium supplementation at doses higher than daily requirement may reduce mortality. We observed no impact of selenium on ICU length of stay or risk of nosocomial pneumonia.

Small bowel feeding and risk of pneumonia in adult critically ill patients: a systematic review and meta-analysis of randomized trials

IntroductionThis systematic review and meta-analysis aimed to evaluate the effect of small bowel feeding compared with gastric feeding on the frequency of pneumonia and other patient-important outcomes in critically ill patients.MethodsWe searched EMBASE, MEDLINE, clinicaltrials.gov and personal files from 1980 to Dec 2012, and conferences and proceedings from 1993 to Dec 2012 for randomized trials of adult critically ill patients in the intensive care unit (ICU) comparing small bowel feeding to gastric feeding, and evaluating risk of pneumonia, mortality, length of ICU stay, achievement of caloric requirements, duration of mechanical ventilation, vomiting, and aspiration. Independently, in duplicate, we abstracted trial characteristics, outcomes and risk of bias.ResultsWe included 19 trials with 1394 patients. Small bowel feeding compared to gastric feeding was associated with reduced risk of pneumonia (risk ratio [RR] 0.70; 95% CI, 0.55, 0.90; P = 0.004; I2 = 0%) and ventilator-associated pneumonia (RR 0.68; 95% CI 0.53, 0.89; P = 0.005; I2 = 0%), with no difference in mortality (RR 1.08; 95% CI 0.90, 1.29; P = 0.43; I2 = 0%), length of ICU stay (WMD -0.57; 95%CI -1.79, 0.66; P = 0.37; I2 = 0%), duration of mechanical ventilation (WMD -1.01; 95%CI -3.37, 1.35; P = 0.40; I2 = 17%), gastrointestinal bleeding (RR 0.89; 95% CI 0.56, 1.42; P = 0.64; I2 = 0%), aspiration (RR 0.92; 95% CI 0.52, 1.65; P = 0.79; I2 = 0%), and vomiting (RR 0.91; 95% CI 0.53, 1.54; P = 0.72; I2 = 57%). The overall quality of evidence was low for pneumonia outcome.ConclusionsSmall bowel feeding, in comparison with gastric feeding, reduces the risk of pneumonia in critically ill patients without affecting mortality, length of ICU stay or duration of mechanical ventilation. These observations are limited by variation in pneumonia definition, imprecision, risk of bias and small sample size of individual trials.

Genetic characterization and diversity of circulating influenza A/H1N1pdm09 viruses isolated in Jeddah, Saudi Arabia between 2014 and 2015

The emerged influenza A/H1N1pdm09 viruses have replaced the previously circulating seasonal H1N1 viruses. The close antigenic properties of these viruses to the 1918 H1N1 pandemic viruses and their post-pandemic evolution pattern could further enhance their adaptation and pathogenicity in humans representing a major public health threat. Given that data on the dynamics and evolution of these viruses in Saudi Arabia is sparse we investigated the genetic diversity of circulating influenza A/H1N1pdm09 viruses from Jeddah, Saudi Arabia, by analyzing 39 full genomes from isolates obtained between 2014-2015, from patients with varying symptoms. Phylogenetic analysis of all gene segments and concatenated genomes showed similar topologies and co-circulation of clades 6b, 6b.1 and 6b.2, with clade 6b.1 being the most predominate since 2015. Most viruses were more closely related to the vaccine strain (Michigan/45/2015) recommended for the 2017/2018 season, than to the California/07/2009 strain. Low sequence variability was observed in the haemagglutinin protein compared to the neuraminidase protein. Resistance to neuraminidase inhibitors was limited as only one isolate had the H275Y substitution. Interestingly, two isolates had short PA-X proteins of 206 amino acids compared to the 232 amino acid protein found in most influenza A/H1N1pdm09 viruses. Together, the co-circulation of several clades and the predominance of clade 6b.1, despite its low circulation in Asia in 2015, suggests multiple introductions most probably during the mass gathering events of Hajj and Umrah. Jeddah represents the main port of entry to the holy cities of Makkah and Al-Madinah, emphasizing the need for vigilant surveillance in the kingdom.

958: EXTRACORPOREAL MEMBRANE OXYGENATION FOR SEVERE MERS-COV: A RETROSPECTIVE OBSERVATIONAL STUDY.

Crit Care Med 2016 • Volume 44 • Number 12 (Suppl.) 1.044, p 0.02). Non-ECPR ECMO patients had lower mortality at last follow-up (21.4%) than those treated with mechanical ventilation alone (42.2%; HR 0.168, p 0.03) despite having a higher median Murray Score (3.75 vs. 3.0, p=0.05). There was no difference in age or nadir PaO2/FiO2 ratio between ECMO and nonECMO patients (p=0.07 and 0.09). Conclusions: In a small cohort of critically ill influenza patients admitted with ARDS during the 2015–2016 H1N1 season, older age and severity of respiratory acidosis increased mortality risk. Our data also suggest that at a high-volume ECMO referral center, non-ECPR VV-ECMO may be associated with improved survival. Larger studies are needed to confirm if severely ill influenza patients can benefit from VV-ECMO.