a b s t r a c tThe aim of this study was to evaluate the effect of augmented renal clearance (ARC) on vancomycin serum concentrations in critically ill patients. This prospective, single-centre, observational, cohort study included 93 consecutive, critically ill septic patients who started treatment that included vancomycin by continuous infusion, admitted over a 2-year period (March 2006 to February 2008. ARC was defined as 24-h creatinine clearance (CL Cr ) > 130 mL/min/1.73 m 2 . Two groups were analysed: Group A, 56 patients with a CL Cr ≤ 130 mL/min/1.73 m 2 ; and Group B, 37 patients with a CL Cr > 130 mL/min/1.73 m 2 . Vancomycin therapeutic levels were assessed on the first 3 days of treatment (D 1 , D 2 and D 3 ). Serum vancomycin levels on D 1 , D 2 and D 3 , respectively, were 13.1, 16.6 and 18.6 mol/L for Group A and 9.7, 11.7 and 13.8 mol/L for Group B (P < 0.05 per day). The correlation between CL Cr and serum vancomycin on D 1 was −0.57 (P < 0.001). ARC was strongly associated with subtherapeutic vancomycin serum concentrations on the first 3 days of treatment.

Background: Critically ill patients show a high, albeit variable, prevalence of augmented renal clearance (ARC). This condition has relevant consequences on the elimination of hydrophilic drugs. Knowledge of risk factors for ARC helps in the early identification of ARC. The aims of this study were evaluation of (1) risk factors for ARC and (2) the prevalence of ARC in critically ill patients over a period of 1 year. Methods: A retrospective cohort study was performed for all consecutive patients admitted to our intensive care unit (ICU). Augmented renal clearance was defined by a creatinine clearance ≥130 mL/min/1.73 m2. “Patient with ARC” was defined as a patient with a median of creatinine clearance ≥130 mL/min/1.73 m2 over the period of admission. Four variables were tested, Simplified Acute Physiology Score II (SAPS II), male gender, age, and trauma as cause for ICU admission. An analysis (patient based and clearance based) was performed with logistic regression. Results: Of 475 patients, 446 were included in this study, contributing to 454 ICU admissions and 5586 8-hour creatinine clearance (8h-CLCR). Overall, the prevalence of patients with ARC was 24.9% (n = 113). In a subset of patients with normal serum creatinine levels, the prevalence was 43.0% (n = 104). Of the set of all 8h-CLCR measurements, 25.4% (1418) showed ARC. In the patient-based analysis, the adjusted odds ratio was: 2.0 (confidence interval [CI]:1.1-3.7; P < .05), 0.93 (CI: 0.91-0.94; P < .01), 2.7 (CI: 1.4-5.3; P < .01), and 0.98 (CI: 0.96 -1.01; P = .15), respectively, for trauma, age, male sex, and SAPS II. In the clearance-based analysis, the adjusted odds ratio were 1.7 (CI: 1.4-1.9; P < .01), 0.94 (CI: 0.932-0.942; P < .01), and 2.9 (CI: 2.4-3.4; P < .01), respectively, for trauma, age, and male sex. Conclusions: Trauma, young age, and male sex were independent risk factors for ARC. This condition occurs in a considerable proportion of critical care patients, which was particularly prevalent in patients without evidence of renal dysfunction.

The paper describes the techniques used in Prudhoe Bay to place small, highly conductive fractures in areas of the field where there is no fracture containment to prevent fracture growth into an aquifer.A reservoir study to investigate the effects of fracturing close to oil water contacts is presented, together with 3D fracture modelling of fractures with no downward containment. The paper highlights the importance of spurt losses in both frac designs and minifrac analyses, when fracturing high permeability reservoirs. A simple minifrac analysis, for use with complex fracture geometries, is provided.The fracture design methodology is presented, supported by field examples.

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Introduction: Hospital-acquired pneumonia continues to be a frequent complication in the intensive care unit and an important cause of admission in the intensive care unit. The aim of our study was to evaluate the demography, incidence, risk factors, causative bacterial pathogens and outcome of all episodes of Hospital-acquired pneumonia in our unit.Material and Methods: Prospective observational study, at a tertiary university hospital during one year (2014) including all the cases of hospital-acquired pneumonia in the intensive care unit.Results: Sixty patients were identified with pneumonia. Thirty-five (58.3%) had an intensive care unit acquired pneumonia, corresponding to 6.9 cases/1000 intubation-days. Antibiotic treatment in the previous 30 days was present in 75% of the cases. The incidence of Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii was 26.2%, 20.0% and 9.2%, respectively. Patients with late-onset hospital-acquired pneumonia (≥ 7 days) showed higher frequency of non-fermenting Gram-negative bacilli isolates, and methicillin-resistant S. aureus. Combination therapy was performed in 67.0%, and de-escalation in 18.3%. The mortality rate was 18.3%. The adjusted odds ratio for intensive care unit mortality in the group of patients with non-intensive care unit acquired pneumonia was 5.2 (95% CI of 1.02 – 22.10; p = 0.046).Discussion: The knowledge of local bacterial flora and resistance patterns is of crucial importance and strongly recommended. This evidence increases the probability of success of empiric antibiotic therapy.Conclusion: S. aureus was the predominant causative agent of nosocomial pneumonia. The most frequent risk factor identified for infection with multidrug-resistant organisms was previous treatment with antibiotics. Multidrug-resistant organisms were present in 45% of documented hospital-acquired pneumonias. In admitted patients with non-intensive care unit acquired pneumonia, the intensive care unit mortality rate was nearly five times higher compared to intensive care unit acquired pneumonia.

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BackgroundArginine is an amino acid determinant in the metabolic, immune and reparative responses to severe trauma. The present study aims to determine argininemia and plasma arginine bioavailability (PAB) in critical trauma patients and to analyze its correlation with prognosis.MethodsA prospective study of 23 critical trauma patients was undertaken. Aminoacidemias were determined, by ion exchange chromatography, at admission and in the first and third days and compared with those of 11 healthy individuals. PAB was calculated. Severity indexes and outcome parameters were recorded.ResultsValues of argininemia, citrullinemia and ornithinemia at the admission were significantly lower than those of the controls (arginine: 41.2 ± 20.6 versus 56.1 ± 11.9 μmol/L, P = 0.034). Hipoargininemia (<60 μmol/L) prevalence was 82.6 %. Mean PAB was 62.4 ± 25.6 %. Argininemia < 26 μmol/L constituted a significant predictive factor of in-hospital mortality [n = 4 (17.4 %); 75 versus 15.8 %, P = 0.04; odds ratio = 4.7; accuracy = 87 %] and lower actuarial survival (63.5 ± 43.9 versus 256.1 ± 33.3 days, P = 0.031). PAB <42 % [n = 6 (26.1 %)] was associated with higher lactacidemia levels (P = 0.033), higher in-hospital mortality (66.7 versus 11.8 %, P = 0.021; odds ratio = 5.7, accuracy = 82.6 %) and lower actuarial survival (87.2 ± 37.5 versus 261.4 ± 34.7 days, n.s.). Probability of in-hospital mortality was inversely and significantly related with PAB [61.8 ± 8.8 % (95 % CI 50.8–72.7) when PAB <41 % and 2.8 ± 1.9 % (95 % CI 1.9–8.3) when PAB > 81 %, P = 0.0001]. Charlson’s index ≥1, APACHE II ≥19.5, SOFA ≥7.5, and glutaminemia < 320 μmol/L were also predictive factors of actuarial survival.ConclusionsThose results confirm the high prevalence of arginine depletion in severe trauma patients and the relevance of argininemia and PAB as predictive factors of mortality in this context.