The Utility of Inflammatory and Endothelial Markers to Identify Infection in Emergency Department Patients

Soluble fms-like tyrosine kinase 1, placental growth factor and procalcitonin as biomarkers of gram-negative sepsis: Analysis through a derivation and a validation cohort

Further improvement of the diagnostic and prognostic performance of biomarkers for the critically ill is needed. Procalcitonin (PCT), placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 raise interest for sepsis diagnosis and prognosis.Serum samples from 2 cohorts of 172 patients (derivation cohort) and of 164 patients (validation cohort) comprising only patients with microbiologically confirmed gram-negative infections were analyzed. PlGF, s-Flt-1 and procalcitonin (PCT) were measured in serum within 24 hours from sepsis onset and repeated on days 3 and 7.PCT and s-Flt-1 baseline levels were higher in sepsis and septic shock compared to non-sepsis; this was not the case for PlGF. s-Flt-1 at concentrations greater than 60 pg/ml diagnosed sepsis with sensitivity 72.3% and specificity 54.9% whereas at concentrations greater than 70 pg/ml predicted unfavorable outcome with specificity 73.0% and sensitivity 63.7%. At least 80% decrease of PCT and/or PCT less than 0.5 ng/ml on day 7 was protective from sepsis-associated death.Both s-Flt-1 and PCT should be measured in the critically ill since they provide additive information for sepsis diagnosis and prognosis.ClinicalTrials.gov numbers NCT01223690 and NCT00297674.

Interleukin-6 improves infection identification when added to physician judgment during evaluation of potentially septic patients

BACKGROUND

Identifying infection is critical in early sepsis screening. This study assessed whether biomarkers of endothelial activation and/or inflammation could improve identification of infection among Emergency Department (ED) patients with organ dysfunction.

METHODS

We performed a prospective, observational study at two urban, academic EDs, between June 2016 and December 2017. We included admitted adults with 1) two systemic inflammatory response syndrome criteria and organ dysfunction, 2) systolic blood pressure < 90 mmHg, or 3) lactate ≥4.0 mmol/L. We excluded patients with trauma, transferred for intracranial hemorrhage, or without available blood samples. Treating ED physicians reported presence of infection (yes/no) at inpatient admission. Assays for angiopoietin-1, angiopoietin-2, soluble tumor necrosis factor receptor-1, interleukin-6, and interleukin-8 were performed using ED blood samples. The primary outcome was infection, adjudicated by paired physician review. Using logistic regression, we compared the performance of physician judgment, biomarkers, and physician judgment-biomarkers combination to predict infection. Area under the curve (AUC) and AUC 95% confidence intervals were estimated by bootstrap procedure.

RESULTS

Of 421 patients enrolled, 306 patients met final study criteria. Of these, 154(50.3%) patients had infectious etiologies. Physicians correctly discriminated infectious from non-infectious etiologies in 239 (78.1%). Physician judgment performed moderately when discriminating infection (AUC 0.78, 95% CI: 0.74-0.82) and outperformed the best biomarker model, interleukin-6 alone, (AUC 0.71, 0.66-0.76). Physician judgment improved when including interleukin-6 (AUC 0.84, 0.79-0.87), with modest AUC improvement: 0.06 (0.03-0.08).

CONCLUSIONS

In ED patients with organ dysfunction, plasma interleukin-6 may improve infection discrimination when added to physician judgment.

Goal-Directed Resuscitation in Septic Shock: A Critical Analysis

The Early Goal-Directed Therapy versus Standard Care for Sepsis trial by Rivers and colleagues in 2001 suggested that a significant mortality reduction may be realized through goal-directed interventions early in the care of patients with septic shock. However, the recent publication of the Protocol-Based Care for Early Septic Shock (ProCESS), Australasian Resuscitation in Sepsis Evaluation (ARISE), and Protocolised Management in Sepsis (ProMISE) trials did not demonstrate the superiority of early goal-directed therapy over usual care. If usual care includes timely and meticulous care, a protocol may not be needed to realize the continued lowering mortality rates.

RECOMBINANT BCL-XL ATTENUATES VASCULAR HYPERPERMEABILITY IN A RAT MODEL OF HEMORRHAGIC SHOCK

Following hemorrhagic shock (HS), vascular hyperpermeability, that is, the leakage of fluid, nutrients and proteins into the extravascular space occurs primarily due to the disruption of the endothelial cell–cell adherens junctional complex. Studies from our laboratory demonstrate that activation of the mitochondria-mediated ‘intrinsic’ apoptotic signaling cascade has a significant role in modulating HS-induced hyperpermeability. Here we report the novel use of recombinant Bcl-xL, an anti-apoptotic protein, to control HS-induced vascular hyperpermeability. Our results corroborate involvement of vascular hyperpermeability and apoptotic signaling. HS (the mean arterial pressure (MAP) was reduced to 40 mm Hg for 60 min followed by resuscitation to 90 mm Hg for 60 min) in rats resulted in vascular hyperpermeability as determined by intravital microscopy. Treatment of Bcl-xL (2.5 µg/ml of rat blood in non-lipid cationic polymer, i.v.) before, during and even after HS attenuated or reversed HS-induced vascular hyperpermeability significantly (P<0.05). Conversely, treatment using Bcl-xL inhibitors, 2-methoxy antimycin (2-OMeAA) and ABT 737, significantly increased vascular hyperpermeability compared with sham (P<0.05). Bcl-xL treatment also decreased the amount of fluid volume required to maintain a MAP of 90 mm Hg during resuscitation (P<0.05). HS resulted in an increased mitochondrial reactive oxygen species formation, reduction of ΔΨm, mitochondrial release of cytochrome c and significant activation of caspase-3 (P<0.05). All of these effects were significantly inhibited by Bcl-xL pre-treatment (P<0.05). Our results show that recombinant Bcl-xL is effective against HS-induced vascular hyperpermeability that appears to be mediated through the preservation of ΔΨm and subsequent prevention of caspase-3 activation.