[Management of infection in immunocompromised patients]. / Infektionsmanagement bei Immunsupprimierten.

The number of immunosuppressed patients continues to increase worldwide. The main reasons are the demographic development and improved long-term survival, also for patients under immunosuppression. A major cause of hospitalization and mortality among these patients are infections. Their management, including prevention and adequate treatment, plays a crucial role in survival and quality of life, but also with regard to economic factors.Infection management in immunocompromised patients faces new challenges today. Not only the increasing number, but also new groups of patients at risk and an increasingly aging and comorbid population pose problems for the treating physicians. While cancer medicine is no longer determined solely by radiotherapy and chemotherapy, new targeted substances are playing an increasingly important role. In addition, new targeted substances complicate adequate infection prophylaxis due to potential interactions. The worldwide increase in antibiotic-resistant pathogens complicates treatment of bacterial infections, which is associated with increased mortality, especially in the immunocompromised patient population. Further, the disruption of the microbiome shows negative antibiotic-associated effects. Hence the reasonable use of anti-infectives in prophylaxis and therapy is of great importance.There are many recommendations and guidelines for clinicians regarding the management of infections in immunocompromised patients. Overlaps of infectiology, hygiene as well as hematology and oncology sometimes lead to different recommendations. This article provides an overview of the currently existing evidence and guidelines for infection management in immunosuppressed patients.

Microbial colonization of pancreatic duct stents: a prospective analysis.

OBJECTIVE: The aim of the study was to analyze the microbial colonization rate as well as the spectrum and number of microorganisms in relation to the indwelling time of pancreatic stents. METHODS: Forty pancreatic stents were prepared according to a standardized protocol and subsequently sonicated to optimize bacterial release from the biofilm on the stents. RESULTS: Two hundred forty-six microorganisms were identified. Thirty-nine of 40 stents were colonized with microorganisms. Aerobic gram-positive microorganisms (106/246 [43%]) accounted for the greatest proportion. The predominant microorganisms were Streptococcus species (46/246 [19%]), which were isolated from 27 (68%) of 40 stents. Stents with a short indwelling time (3-13 days) were mainly colonized with aerobic gram-positive bacteria (82%) and Candida species (63%). In contrast, anaerobes (P < 0.01, 69% vs 18%) and aerobic gram-negative microorganisms (P < 0.01, 93% vs 45%) such as Enterobacteriaceae (P < 0.01, 86% vs 27%) were significantly more present on stents with a long indwelling time (29-93 days), compared with stents with a short indwelling time. CONCLUSIONS: Microbial analysis of pancreatic duct stents revealed a very high colonization rate. Furthermore, the spectrum and number of microorganisms altered with the indwelling time of the stent. However, clinical relevance of our findings remains unclear.

Biliary endoprosthesis: a prospective analysis of bacterial colonization and risk factors for sludge formation.

Bacterial colonization of biliary stents is one of the driving forces behind sludge formation which may result in stent occlusion. Major focus of the study was to analyze the spectrum and number of microorganisms in relation to the indwelling time of stents and the risk factors for sludge formation. 343 stents were sonicated to optimize the bacterial release from the biofilm and identified by matrix-associated laser desorption/ionization-time of flight mass spectrometer (MALDI-TOF). 2283 bacteria were analyzed in total. The most prevalent microorganisms were Enterococcus species (spp.) (504;22%), followed by Klebsiella spp. (218;10%) and Candida spp. (188;8%). Colonization of the stents mainly began with aerobic gram-positive bacteria (43/49;88%) and Candida spp. (25/49;51%), whereas stents with an indwelling time>60 days(d) showed an almost equal colonization rate by aerobic gram-negative (176/184;96%) and aerobic gram-positive bacteria (183/184;99%) and a high proportion of anaerobes (127/184;69%). Compared to stents without sludge, more Clostridium spp. [(P = 0.02; Odds Ratio (OR): 2.4; 95% confidence interval (95%CI): (1.1-4.9)]) and Staphylococcus spp. [(P = 0.03; OR (95%CI): 4.3 (1.1-16.5)] were cultured from stents with sludge. Multivariate analysis revealed a significant relationship between the number of microorganisms [P<0.01; OR (95%CI): 1.3(1.1-1.5)], the indwelling time [P<0.01; 1-15 d vs. 20-59 d: OR (95%CI): 5.6(1.4-22), 1-15 d vs. 60-3087 d: OR (95% CI): 9.5(2.5-35.7)], the presence of sideholes [P<0.01; OR (95%CI): 3.5(1.6-7.9)] and the occurrence of sludge. Stent occlusion was found in 70/343(20%) stents. In 35% of cases, stent occlusion resulted in a cholangitis or cholestasis. In conclusion, microbial colonization of the stents changed with the indwelling time. Sludge was associated with an altered spectrum and an increasing number of microorganisms, a long indwelling time and the presence of sideholes. Interestingly, stent occlusion did not necessarily lead to a symptomatic biliary obstruction.

Functional hemodynamic parameters do not reflect volume responsiveness in the immediate phase after acute myocardial ischemia and reperfusion.

OBJECTIVE: Functional preload parameters such as stroke-volume variation (SVV) and pulse-pressure variation (PPV) are superior to filling pressures when assessing volume responsiveness in mechanically ventilated patients. This investigation studied their application in the setting of acute myocardial ischemia and reperfusion (I/R). DESIGN AND SETTING: Experimental animal study in a university laboratory. PARTICIPANTS: Twenty anesthetized and ventilated pigs. INTERVENTIONS: A temporary reduction of preload was obtained by ventilation with a positive end-expiratory pressure of 10 cmH(2)O. Ischemia was induced by temporary occlusion of the left anterior descending coronary artery for 60 minutes and was followed by 30 minutes of reperfusion. MEASUREMENTS AND MAIN RESULTS: Animals were instrumented with an ultrasonic aortic flow probe to monitor stroke volume (SV) and SVV. Arterial pressure and PPV were recorded with a microtip catheter; left ventricular volume and pressure were registered by a conductance catheter. Respective hemodynamic measurements were made before, during, and after PEEP; before and after the induction of I/R. Eleven animals survived I/R and were analyzed. Before I/R, SVV (r = 0.87, p < 0.001) and PPV (r = 0.75, p < 0.05) during PEEP correlated significantly with relative changes in SV caused by the release of PEEP. Changes in SVV (r = 0.82, p < 0.01) and PPV (r = 0.67, p < 0.05) correlated significantly with relative changes in SV. After I/R, neither the relations between changes in SV to SVV or PPV during PEEP nor the relations between changes in SVV or PPV to changes in SV reached significance. CONCLUSIONS: SVV and PPV did not reflect volume responsiveness in an experimental model of acute myocardial I/R.

Systolic pressure variation and pulse pressure variation during modifications of arterial pressure.

OBJECTIVE: This study was performed to investigate the effect of vasopressor therapy on systolic pressure variation (SPV) and pulse pressure variation (PPV) compared to experimentally measured left ventricular stroke volume variation (SVV). DESIGN AND SETTING: Prospective study in a university laboratory. SUBJECTS: Twelve anesthetized and mechanically ventilated pigs. INTERVENTIONS: Increase in mean arterial pressure (by 100%) using phenylephrine and decrease (by 38%) using adenosine. MEASUREMENTS AND RESULTS: SPV and PPV were calculated and compared to SVV derived from aortic blood flow measurements. SPV was significantly affected by changes in arterial pressure [4.6% (1.5) vs. 6.3% (2.1), p < 0.05, increased vs. decreased arterial pressure], whereas PPV did not change during modifications of arterial pressure. During baseline conditions and decreased afterload, correlation with SVV was good both for SPV (r =0.892 and r = 0.859, respectively) and for PPV (r = 0.870 and r = 0.871, respectively) (all p < 0.001). Correlation with SVV was only moderate during increased arterial pressure (r = 0.683 for SPV and r = 0.732 for PPV, p < 0.05). CONCLUSION: For guiding fluid therapy in patients under vasopressor support, PPV seems superior to SPV.

The influence of positive end-expiratory pressure on stroke volume variation and central blood volume during open and closed chest conditions.

OBJECTIVE: Intermittent positive pressure ventilation and positive end-expiratory pressure (PEEP) affect cardiac preload. Their effect is dependent on chest wall compliance. This study compares the effects of intermittent positive pressure ventilation and PEEP on stroke volume variation and central blood volume during open and closed chest conditions. MATERIALS AND METHODS: Fourteen anesthetized and mechanically ventilated pigs (25-40 kg) were studied. Central blood volume was assessed using global end-diastolic volume and right ventricular end-diastolic volume measured by thermodilution. Further, left and right ventricular stroke volume variations were determined with ultrasonic flow probes placed around the pulmonary artery and ascending aorta, respectively. Measurements were performed during mechanical ventilation without and with PEEP (15 cmH(2)O) in open and closed chest conditions. RESULTS: With the chest closed mean arterial pressure, cardiac output, stroke volume, global end-diastolic volume, and right ventricular end-diastolic volume were significantly lower when compared to open chest conditions. Concomitantly, right ventricular, but not left ventricular stroke volume variation increased significantly. Applying PEEP led to a significant reduction of cardiac output, stroke volume and right ventricular end-diastolic volume, with a concomitant increase in left and right ventricular stroke volume variation both during open and closed chest conditions (all P-values<0.05). CONCLUSIONS: We conclude that PEEP increases right and left ventricular stroke volume variation both during open and closed chest conditions. The concomitant reduction of right ventricular end-diastolic volume further indicates that PEEP has a preload reductive effect during open chest conditions, too.