MICROBIAL PROFILE AND ANTIBIOTIC SUSCEPTIBILITY PATTERNS OF PATHOGENS CAUSING VENTILATOR- ASSOCIATED PNEUMONIA AT INTENSIVE CARE UNIT, SESTRE MILOSRDNICE UNIVERSITY HOSPITAL CENTER, ZAGREB, CROATIA.

Ventilator-associated pneumonia (VAP) is very common in many intensive care Units, but there are still many uncertainties about VAP, especially about the choice of initial empiric antibiotics. The incidence of specific pathogens with different susceptibility patterns causing VAP varies from hospital to hospital. This is the reason why empiric initial antibiotic treatment for VAP should be based not only on general guidelines (that recommend therapy according to the presence of risk factors for multidrug-resistant bacteria), but also on up-to-date information on local epidemiology. The aim of this study was to determine the microbial profile of pathogens causing VAP and their antibiotic susceptibility patterns. The study was conducted in the 15-bed surgical and neurosurgical Intensive Care Unit, Department of Anesthesiology and Intensive Care, Sestre milosrdnice University Hospital Center, Zagreb, Croatia. Retrospective data were collected from September 2009 to March 2013. All patients that developed VAP during the study period were eligible for the study. According to study results, the incidence of VAP was 29.4%. The most commonly isolated bacterium was Staphylococcus aureus (21.1%), followed by Pseudomonas aeruginosa (19.0%) and Acinetobacter species (13.6%). All Staphylococcus aureus isolates were susceptible to vancomycin and linezolid. Pseudomonas aeruginosa showed 100% susceptibility to cefepime and very high susceptibility to pip'eracillin-tazobactam (96%), ceftazidime (93%) and ciprofloxacin (89%). Ampicillin-sulbactam was highly effective for Acinetobacter species, showing resistance in only 8% of isolates. In conclusion, according to study data, appropriate empiric antibiotic therapy for patients with VAP without risk factors for multidrug-resistant bacteria is ceftriaxone and for patients with risk factors for multidrug-resistant bacteria ampicillin-sulbactam plus cefepime plus vancomycin or linezolid.

Positive end-expiratory pressure lung recruitment: comparison between lower inflection point and ultrasound assessment.

BACKGROUND: Maintenance of the open lung alveoli in the expiration on mechanical ventilation in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) remains challenging despite advances in lung imaging. The inspiratory lower inflection point (LIP) on the ventilator pressure-volume (P-V) curve estimates the required end-expiratory pressure for recruitment of alveolar consolidation. Alternatively, the end-expiratory pressure for recruitment of crater-like subpleural alveolar consolidation could be simply followed with ultrasound. These two methods for setting the ventilators positive end-expiratory pressure (PEEP) were compared. METHODS: The observational study in surgical/neurosurgical intensive care between October 2009 and November 2011 included 17 deeply sedated or relaxed patients. LIP was measured with continuous low-flow method, as a pressure in cmH(2)O. Expiratory levelling between lower border of subpleural consolidation and adjacent pleural line, which means lung recruitment, was followed with linear ultrasound probe. PEEP in cmH(2)O at which the levelling occurs was compared with LIP pressure. RESULTS: LIP pressure never exceeds the PEEP for recruitment of subpleural consolidations followed with ultrasound. A significant correlation (r = 0.839; p < 0.05) was found between two methods. CONCLUSIONS: In this study, positive end-expiratory pressures for recruitment of subpleural consolidations followed by ultrasound always exceed the pressures measured with LIP. Respecting this, ultrasound method could be the guide for PEEP lung recruitment.

Prognostic performance of the Simplified Acute Physiology Score II in major Croatian hospitals: a prospective multicenter study.

AIM: To perform an external validation of the original Simplified Acute Physiology Score II (SAPS II) system and to assess its performance in a selected group of patients in major Croatian hospitals. METHODS: A prospective, multicenter study was conducted in five university hospitals and one general hospital during a six-month period between November 1, 2007 and May 1, 2008. Standardized hospital mortality ratio (SMR) was calculated from the mean predicted mortality of all the 2756 patients and the actual mortality for the same group of patients. The validation of SAPS II was made using the area under receiver operating characteristic curve (AUC), 2×2 classification tables, and Hosmer-Lemeshow tests. RESULTS: The predicted mortality was as low as 14.6% due to a small proportion of medical patients and the SMR being 0.89 (95% confidence interval [CI], 0.78-0.98). The SAPS II system demonstrated a good discriminatory power as measured by the AUC (0.85; standard error [SE]=0.012; 95% CI=0.840-0.866; P<0.001). This system significantly overestimated the actual mortality (Hosmer-Lemeshow goodness-of-fit H statistic: χ(2) =584.4; P<0.001 and C statistics: χ(2)(8) =313.0; P<0.001) in the group of patients included in the study. CONCLUSION: The SAPS II had a good discrimination, but it significantly overestimated the observed mortality in comparison with the predicted mortality in this group of patients in Croatia. Therefore, caution is required when an evaluation is performed at the individual level.

Ultrasonographic finding of lung sliding in patients on mechanical ventilation with alveolar-interstitial syndrome.

BACKGROUND AND OBJECTIVES: To determine the visibility of pleural lung sliding in alveolar-interstitial syndrome (AIS) in patients on mechanical ventilation at two different time points, as a confirmatory ultrasonographic method for excluding pneumothorax. METHODS: Fifty-two mechanically ventilated patients in the semirecumbent position in a surgical/neurosurgical intensive care unit with ultrasonographic lung 'comet tails' in three upper anterolateral intercostal spaces, indicating the presence of AIS, were scanned for lung sliding in the same three intercostal spaces with a linear 5-10 MHz transducer after starting mechanical ventilation and on weaning trials. Pneumothorax and atelectasis were excluded by chest radiograph. RESULTS: Absent lung sliding was found in 22.7% of intercostal spaces scanned after starting mechanical ventilation and in 21.2% of scans taken on weaning trials. The lowest invisible rate was in patients with acute heart failure and the highest in patients with acute respiratory distress syndrome. CONCLUSION: Lung sliding specificity in AIS during mechanical ventilation was 78%. Our opinion is that different levels of airway pressure between starting mechanical ventilation and weaning trials have no influence on lung sliding visibility.

Human soluble TREM-1: lung and serum levels in patients with bacterial ventilator associated pneumonia.

Human soluble triggering receptor expressed on myeloid cells (sTREM-1) is a glycoprotein of the immunoglobulin superfamily. In normal lung tissue, sTREM-1 is selectively expressed in lung alveolar macrophages specialized for pathogen clearance and is up-regulated in the presence of bacteria and fungi. The aim of this study was to assess sTREM-1 levels in serum and lungs of patients with ventilator associated pneumonia (VAP) and to evaluate its potential diagnostic role. The study cohort included 31 patients meeting the criteria for VAP, including clinical, microbiological, radiological and laboratory findings in patients on mechanical ventilation for more than 48 hours and with Clinical Pulmonary Infection Score (CPIS) > 6. Serum and lung levels of sTREM-1 were obtained and tested for differences. The samples were analyzed using ELISA technique and the values were expressed in pg/mL. The samples for lung sTREM-1 were obtained from direct bronchial lavage fluid and serum samples from peripheral blood. Differences were tested by Mann Whitney U test with P < 0.05 considered significant. In patients with bacterial VAP, a statistically significant difference was found between serum and lung sTREM-1 levels (P < 0.05), with very high levels of sTREM-1 recorded in lung samples (mean value 1565 pg/mL). There was no statistically significant difference in pulmonary sTREM-1 level between the polymicrobial and monomicrobial VAP groups. In conclusion, sTREM-1 is present in a high concentration in the lungs of patients with bacterial VAP. sTREM-1 levels can help in making the diagnosis of bacterial pneumonia as a standalone marker.

Constant cardiac output monitoring using the PiCCO and LiDCO methods versus PAK in septic patients: when to do calibration?

The accuracy of cardiac output measurement by two most widely used methods of less invasive hemodynamic monitoring and by the standard technique of thermodilution with pulmonary catheter was assessed. The measurements were carried out in septic surgical patients immediately after and between system calibrations. Study results showed satisfactory compatibility of measurements performed by the two methods and by pulmonary catheter in both phases, thus system calibration being recommendable in hemodynamically unstable septic patients.

Plasma interleukin-8 as a potential predictor of mortality in adult patients with severe traumatic brain injury.

Because of complex pathophysiology and severe consequences, traumatic brain injuries (TBI) are an important medical problem. Pathophysiology of TBI includes local and systemic stress response, in which interleukin-8 (IL-8) is considered as a key mediator of neuroinflammation. However, prognostic relevance of IL-8 measurement in adult patients with severe TBI is not certain. Therefore, IL-8 was determined in blood samples from central venous and jugular bulb catheter and in cerebrospinal fluid of twenty patients with isolated TBI at admission to Intensive Care Unit. None of the patients had history of stroke, dementia, autoimmune diseases, acute infection or medication with anti-inflammatory drugs. Ten patients died due to traumatic brain injury, while the other ten recovered well. While there was no significant difference of IL-8 levels in cerebrospinal fluid between survivors and nonsurvivors, central venous plasma level of IL-8 was significantly lower in survivors (71.00 +/- 14.17 pg/ml), than in nonsurvivors (111.26 +/- 16.9 pg/ml). Receiver Operating Characteristic (ROC) analysis revealed significant prognostic value for IL-8 in the blood as well as for the age of patients, Glasgow Coma Scale (GCS) and Acute Physiologic and Chronic Health Evaluation (APACHE II). These findings suggest that the central venous plasma values of IL-8 at admission might be an early predictive marker in patients with severe TBI, comparative to standard clinical prognostic markers such as APACHE II and GCS.