IntroductionAlthough the prognostic value of persistent hyperlactatemia in septic shock is unequivocal, its physiological determinants are controversial. Particularly, the role of impaired hepatic clearance has been underestimated and is only considered relevant in patients with liver ischemia or cirrhosis. Our objectives were to establish whether endotoxemia impairs whole body net lactate clearance, and to explore a potential role for total liver hypoperfusion during the early phase of septic shock.MethodsAfter anesthesia, 12 sheep were subjected to hemodynamic/perfusion monitoring including hepatic and portal catheterization, and a hepatic ultrasound flow probe. After stabilization (point A), sheep were alternatively assigned to lipopolysaccharide (LPS) (5 mcg/kg bolus followed by 4 mcg/kg/h) or sham for a three-hour study period. After 60 minutes of shock, animals were fluid resuscitated to normalize mean arterial pressure. Repeated series of measurements were performed immediately after fluid resuscitation (point B), and one (point C) and two hours later (point D). Monitoring included systemic and regional hemodynamics, blood gases and lactate measurements, and ex-vivo hepatic mitochondrial respiration at point D. Parallel exogenous lactate and sorbitol clearances were performed at points B and D. Both groups included an intravenous bolus followed by serial blood sampling to draw a curve using the least squares method.ResultsSignificant hyperlactatemia was already present in LPS as compared to sham animals at point B (4.7 (3.1 to 6.7) versus 1.8 (1.5 to 3.7) mmol/L), increasing to 10.2 (7.8 to 12.3) mmol/L at point D. A significant increase in portal and hepatic lactate levels in LPS animals was also observed. No within-group difference in hepatic DO2, VO2 or O2 extraction, total hepatic blood flow (point D: 915 (773 to 1,046) versus 655 (593 to 1,175) ml/min), mitochondrial respiration, liver enzymes or sorbitol clearance was found. However, there was a highly significant decrease in lactate clearance in LPS animals (point B: 46 (30 to 180) versus 1,212 (743 to 2,116) ml/min, P <0.01; point D: 113 (65 to 322) versus 944 (363 to 1,235) ml/min, P <0.01).ConclusionsEndotoxemia induces an early and severe impairment in lactate clearance that is not related to total liver hypoperfusion.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0928-3) contains supplementary material, which is available to authorized users.

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Introduction: The Brighton Spondylodiscitis Score (BSS) aims to identify patients with pyogenic spinal infections (PSIs) requiring surgery; an independent assessment of the BSS is required. Methods: We evaluated 60 patients with PSIs. Using the BSS, we determined whether patients with low, moderate, and high risk (LMHR) had different rates of surgery. We proposed a modified score (MS) using a logistic regression (LOGR). Applying the MS, we determined whether patients with LMHR exhibited different rates of surgery. Another LOGR determined the association of the BSS and the MS with surgery. A C-statistic using the BSS and the MS was generated. Results: We studied 60 patients (mean age = 63 years); 37 (62%) were men; 30 (50%) required surgery. Using the BSS, patients with LMHR had similar rates of surgery (P = 0.53). LOGR showed that cervical PSIs had a larger chance of surgery (odds ratio [OR] = 7.3 [1.1 to 51.3]) than other locations. Using the MS, patients with moderate- and high-risk were operated more frequently than low-risk patients (P = 0.04). The BSS did not predict surgery (OR = 1.07; P = 0.31), but the MS did (OR = 1.16; P = 0.02). The C-statistic using the BSS (0.59) improved using the MS (0.69), P = 0.03. Discussion: The discriminatory capacity to predict surgery of the BSS augmented using the MS. Level of Evidence: II (Diagnostic study: Transverse study)

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Objective: Low back pain is frequently seen in patients visiting the ED, but many patients receive medical care with no demonstrable benefits. We studied the clinical characteristics of patients visiting two EDs in Santiago, Chile, and their management to evaluate how it adheres to evidence-based recommendations. Methods: We studied 519 patients and retrieved their demographic and clinical data, imaging testing and treatments. We determined the effect of sex, age, time from initial symptoms, pain measured with the visual analogue scale, presence of nerve radiation and the presence of red flags and neurological impairment on image testing and the management received. Results: Mean age was 43.8 years; 57.8% were females. Females presented more often red flags (7.3 vs 3%, P = 0.04) and worse pain (visual analogue scale = 7 vs 6, P = 0.04) than males. Imagings were performed in 18.9% of patients; they were more frequently performed in patients with neurological impairment (P = 0.03) and red flags (P = 0.01). Intravenous non-opioids were administered in 25.6%; opioids were administered in 40.1%. Median time in the ED was 91 min (range 18-591); 16 (3.08%) patients were admitted. Age (odds ratio [OR] 1.04 [1.03-1.05], P < 0.01) and red flags (OR 4.9 [1.60-20.08], P < 0.01) influenced imaging testing; pain intensity influenced opioid use (OR 1.6 [1.29-1.95], P < 0.01), hospital admissions (1.95 [1.14-3.33], P < 0.01) and time in the ED (β = 0.5, P < 0.01). Conclusion: Older age, the presence of red flags and pain intensity influenced the management of patients with low back pain in the ED. Future strategies should emphasise avoiding costly and ineffective management in these patients.