Esther Villarreal

Blood culture contamination rate in an intensive care setting: Effectiveness of an education-based intervention

BACKGROUND Blood culture (BC) contamination rate is an indicator of quality of care scarcely explored in intensive care units (ICUs). We analyzed the BC contamination rate in our ICU to assess the effectiveness of an education-based intervention. METHODS We conducted an interventional study with concurrent controls. Consecutive BCs drawn during a 6-month period were included. An education-based intervention was presented to case nurses (optimal technique). The remaining nurses comprised the control group (standard technique). Two independent observers assessed clinical significance of saprophytic skin bacteria isolated in BCs. RESULTS Six hundred fifty-six BCs were obtained: 308 (47%) via optimal technique and 348 (53%) via standard technique (47%). One hundred eighty-seven BCs were positive for saprophytic microorganisms; 127 (89%) were considered unrelated to infection. Coagulase-negative staphylococci isolation was lower in the optimal technique group (14% vs 26%; P < .001), as well as contamination due to coagulase-negative staphylococci (12% vs 21%; P = .002) or Acinetobacter baumannii (0.3% vs 2%; P = .013). BC contamination rate was 13% in the optimal technique group versus 23% in the standard group (P < .005). In the optimal technique group, BC contamination rate was higher in BCs drawn through the catheter (17% vs 7%; P = .028). CONCLUSIONS An education-based intervention significantly reduced the BC contamination rate in our ICU. It seems necessary to design a tool to extract BCs through the catheter to minimize the risk of contamination.

Utilidad de la procalcitonina para el diagnóstico de infección en el paciente crítico con cirrosis hepática

OBJECTIVE To evaluate the usefulness of procalcitonin (PCT) for diagnosing infection in patients with liver cirrhosis admitted to an Intensive Care Unit. DESIGN A retrospective study was carried out. SCOPE Intensive Care Unit. Versatile, twenty-four beds. Participants Patients with liver cirrhosis admitted to our Intensive Care Unit in the last four years with suspected infection and measurement of PCT. RESULTS Among the 255 patients with cirrhosis admitted to our unit, PCT was determined for the differential diagnosis of infection in 69 cases (27%). Three patients were excluded from analysis due to a lack of clinical data. The average stay was 10.6 ± 9.2 days, with a mortality rate of 65%. The origin of cirrhosis was mainly viral (57%) or alcoholic (37%). The Child-Pugh and MELD scores were 9.5 ± 2 and 23 ± 8, respectively. Infection was diagnosed in 54 patients (82%). The most common infection was pneumonia (72%), followed by intraabdominal infections (18%) and bacteremia (5%). In patients without infection, the median PCT concentration was 0.57 ng/ml (range 0.28 to 1.14) versus 2.99 (1.31 to 9.4) in those with infection (p<.001). Diagnostic capacity was maintained in patients with intraabdominal infections. The diagnostic cutoff point was set at 0.8 ng/ml (sensitivity 83%, specificity 75%, AUC 0.82 [0.702-0.93]). CONCLUSIONS In patients with liver cirrhosis, PCT is useful for identifying bacterial infections, including intraabdominal processes.

Diagnosing external ventricular drain-related ventriculitis by means of local inflammatory response: soluble triggering receptor expressed on myeloid cells-1

IntroductionExternal ventricular drainage (EVD)-related ventriculitis is one of the most severe complications associated with the use of EVDs. Establishing an early and certain diagnosis can be difficult in critically ill patients. We performed this prospective study to evaluate the usefulness of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) determination in cerebrospinal fluid (CSF) in the diagnosis of ventriculitis.MethodsA prospective observational study was conducted of 73 consecutive patients with EVD. Samples of CSF for culture, cytobiochemical analysis and sTREM-1 determination were extracted three times a week. Ventriculitis diagnosis required a combination of microbiological, cytobiochemical and clinical criteria.ResultsSeventy-three consecutive patients were included. EVD-related ventriculitis was diagnosed in six patients and EVD-colonization in ten patients. Patients without clinical or microbiological findings were considered controls. The median CSF sTREM-1 was 4,320 pg/ml (interquartile range (IQR): 2,987 to 4,886) versus 266 pg/ml (118 to 689); P <0.001. There were no differences when comparing colonized-patients and controls. The best cut-off sTREM-1 value for the diagnosis of ventriculitis was 2,388.79 pg/ml (sensitivity 100%, specificity 98.5%, positive predictive value 85.71%, negative predictive value 100%). CSF proteins, glucose and the ratio CSF/serum glucose were also significantly different (P = 0.001). Serum biomarkers were not useful to diagnose EVD-related infection. These results were confirmed by a case°Control study with ventriculitis patients (cases) and non-ventriculitis (control subjects) matched by age, comorbidities, severity scales and EVD duration (P = 0.004).ConclusionsCSF sTREM-1 was useful in the diagnosis of ventriculitis, in a similar measure to classical CSF parameters. Furthermore, CSF sTREM-1 could prove the diagnosis in uncertain cases and discriminate between EVD-colonization and infection.

Impact of amikacin pharmacokinetic/pharmacodynamic index on treatment response in critically ill patients

OBJECTIVES This study evaluated the association between the pharmacokinetic/pharmacodynamic index and treatment response to amikacin in critically ill patients. METHODS An observational prospective study was designed. Critically ill adult patients with infection due to amikacin-sensitive Gram-negative bacteria treated with amikacin were included. Amikacin maximum (Cmax) and minimum (Cmin) plasma concentration samples were taken during the first 48-96h after the beginning of treatment. The impact of Cmax/MIC ratio and area under the concentration-time curve (AUC)/MIC ratio on early and final clinical response, microbiological eradication, development of resistant strains and renal toxicity was analysed using a multivariate model. RESULTS A total of 85 patients received amikacin treatment, of whom 71 (83.5%) achieved a Cmax/MIC >6, 66 (77.6%) a Cmax/MIC >8, 64 (75.3%) a Cmax/MIC >10 and 72 (84.7%) an AUC/MIC >65. Clinical response at the end of treatment was significantly greater in patients with Cmax/MIC >6 [OR=5.48 (95% CI 1.28-11.40)], Cmax/MIC >8 [OR=6.01 (2.41-12.2)] and Cmax/MIC >10 [OR=8.02 (2.21-14.2)]. Cmax/MIC >10 was associated with a non-significant increase in microbiological eradication [OR=2.84 (0.76-10.61)]. Achieving Cmax/MIC >6 was associated with a lower proportion of patients with selection of resistant strains or with an increase in amikacin MIC (27.8% vs. 10.2%). Amikacin AUC was associated with development of nephrotoxicity [ROC curve 0.77 (0.66-0.87)]. CONCLUSIONS The Cmax/MIC ratio of amikacin in critically ill patients is directly related to the response to treatment and the selection of resistant strains.

Vancomycin and daptomycin minimum inhibitory concentrations as a predictor of outcome of methicillin-resistant Staphylococcus aureus bacteraemia

OBJECTIVES The aim of this study was to determine the persistence of the adverse prognostic effect of elevated vancomycin minimum inhibitory concentration (MIC) in methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia in a setting with low vancomycin use. METHODS A retrospective study focusing on episodes of bacteraemia due to MRSA diagnosed from January 2010 through December 2015 was designed. The main outcome measures were 30-day mortality and treatment failure. Multivariate logistic regression analysis was used to identify variables associated with patient mortality and treatment outcome. RESULTS In total, 79 MRSA bacteraemia episodes were included. The vancomycin MIC was >1.0μg/mL in 53 episodes (67.1%). The presence of high vancomycin MIC was not associated with a higher mortality rate or treatment success. A daptomycin MIC≥0.5μg/mL was present in 16 (26.2%) of 61 episodes for which the daptomycin MIC was obtained and was associated with 30-day mortality in the multivariate analysis (odds ratio=4.72, 95% confidence interval 1.19-18.71). None of the antimicrobials used were associated with a lower risk of treatment failure or mortality. CONCLUSIONS The pernicious effect of high vancomycin MIC disappears in the absence of a predominant use of this antibiotic. However, a high daptomycin MIC in MRSA bacteraemia is associated with higher mortality in patients with bacteraemia, irrespective of antimicrobial treatment choice.

Individualised antimicrobial dosing in critically ill patients undergoing continuous renal replacement therapy: focus on total drug clearance

Background Continuous renal replacement therapy (CRRT) is common practice in critical care patients with acute renal failure. Objectives To evaluate the adequacy of antimicrobial doses calculated based on the total drug clearance and dose recommended by different guides in critically ill patients undergoing CRRT. Methods Retrospective observational study. Patients admitted to a critical care unit during May 2014 to May 2016 and subjected to CRRT were included. The recommended dose was established as the product of the usual dose of the drug by total drug clearance. Results 177 antimicrobial agents, used in 64 patients were analysed; 45 (25.4%) antimicrobials were given in an insufficient dose (<20%) according to the theoretical calculation. Following the recommendations in the revised guidelines, between 10% and 20% of antimicrobials were given in insufficient doses. A higher success rate of treatment in those patients not receiving a low drug dosage was seen (35.2% vs 24.0%). Conclusions There is a great disparity between the antimicrobial dose prescribed, recommended and calculated based on drug clearance in critically ill patients undergoing CRRT.

Implication of Haemodiafiltration Flow Rate on Amikacin Pharmacokinetic Parameters in Critically Ill Patients

Background: To analyse the effect of haemodiafiltration (CVVHDF) flow rate on amikacin pharmacokinetics and blood concentrations. Methods: Prospective observational study. Patients receiving CVVHDF and amikacin treatment were included. Pharmacokinetic parameters were calculated using Bayesian analysis. Spearman correlation test was used in order to assess the influence of CVVHDF flux on amikacin minimum concentration (Cmin) and plasma clearance. Results: Thirty patients undergoing CVVHDF procedures were included. The treatment with amikacin started at an initial mean dose of 12.4 (4.1) mg/kg/day. An association between the flow rate and Cmin value (r = 0.261; p = 0.161) and plasma clearance was found (r = 0.268; p = 0.152). Four patients (13.3%) were not able to achieve peak concentration over MIC value higher than 8. In 4 patients, amikacin had to be discontinued due to a high Cmin value. Conclusions: Amikacin clearance in patients with CVVHDF is affected by the flow rate used. Therefore, CVVHDF dose should be taken into account when dosing amikacin.

Síndrome coronario agudo provocado por un aneurisma de la arteria coronaria derecha

A 74-year-old woman with cardiovascular risk factor was seen in the emergency service due to self-limiting oppressive central chest pain accompanied by neurovegetative manifestations. The electrocardiographic tracing revealed an inferior subepicardial lesion. Coronary angiography showed a highly ectasic right coronary artery with slowed flow and contrast penetration into the pericardium. In view of these atypical findings, echocardiography was performed, revealing a rounded mass (8.6 cm × 6 cm) exerting an extrinsic compressive effect at atrioventricular sulcus level (Fig. 1). Coronary CT in turn showed active bleeding dependent on the right coronary artery, producing a hematoma contained in the epicardium (pseudoaneurysm), with absence of flow in the distal segment probably secondary to compression (Fig. 2). Based on these tests we diagnosed acute myocardial infarction secondary to right coronary aneurysm, and surgical revascularization of the distal right coronary was decided. The postoperative course proved favorable, and the patient was discharged home within a week.