In vitro clearance of dexmedetomidine in extracorporeal membrane oxygenation

Dexmedetomidine (DMET) is a useful agent for sedation, both alone and in combination with other agents, in critically ill patients, including those on extracorporeal membrane oxygenation (ECMO) therapy. The drug is a clonidine-like derivative with an 8-fold greater specificity for the alpha 2-receptor while maintaining respiratory and cardiovascular stability. An in vitro ECMO circuit was used to study the effects of both “new” and “old” membrane oxygenators on the clearance of dexmedetomidine over the course of 24 hours. Once primed, the circuit was dosed with 840 μg of dexmedetomidine for a final concentration of 0.9 μg/ml. Serial samples, both pre- and post-oxygenator, were taken at 5, 60, 360, and 1440 minutes. Concentrations of the drug were expressed as a percentage of the original concentration remaining at each time point, both for new and old circuits. The new circuits were run at a standard flow for 24 hours, after which time the circuit was considered old and re-dosed with dexmedetomidine and the trial repeated. Results show that dexmedetomidine losses occur early in the circuits and then continue to decline. Initial losses in the first hour were 11+-65% and 59-73% pre- and post-oxygenator in the new circuit and 36-50% and 42-72% in the old circuit. The clearance of the drug through the membrane oxygenator exhibits no statistical difference between pre and post or new and old circuits. Dexmedetomidine can be expected to exhibit concentration changes during ECMO therapy. This effect appears to be more related to adsorption to the polyvinyl chloride (PVC) tubing rather than the membrane oxygenator. Dosage adjustments during dexmedetomidine administration during ECMO therapy may be warranted in order to maintain adequate serum concentrations and, hence, the desired degree of sedation.*(Lack of equilibrium)

Osteoporotische Frakturen des Beckenrings

Durch die Alterung der Bevölkerung sind wir mit einer Zunahme an osteoporotischen und Ermüdungsfrakturen des Beckenrings konfrontiert. Sie werden durch niedrigenergetische Traumen verursacht. Die konventionelle Diagnostik ist weniger aufschlussreich als bei Jugendlichen und Erwachsenen, eine CT- oder MRT-Diagnostik ist erforderlich. Die Erscheinungsformen sind multipel und bieten ein ganzes Spektrum von Instabilitäten. Die konventionelle Klassifikation trifft nicht auf alle Erscheinungsformen dieser Frakturen zu. Die Behandlung umfasst sowohl konservative als auch operative Verfahren. Entscheidend dabei sind der Grad und die Lokalisation der Instabilität. Die Osteosyntheseformen unterscheiden sich von denen der Beckenringfrakturen bei Erwachsenen. Der transsakrale Positionsstab, die iliolumbale Fixation und die winkelstabile Plattenosteosynthese kommen zunehmend zum Einsatz.

Impact of initial intervention on long-term neurological recovey after cardiac arrest: data from the Luxembourg "North Pole" cohort

BACKGROUND

Prognosis after cardiac arrest is variable and difficult to predict. Early prognostic markers would facilitate the care of these patients.

AIMS

Therefore, we evaluated the impact of initial interventions after resuscitation on neurological outcome at 6 months.

MATERIAL AND METHODS

We conducted a retrospective analysis of the patient charts from consecutive cardiac arrest patients admitted to our intensive care unit and treated with induced hypothermia.

RESULTS

Over a 3-year period, 90 patients were included in our study. Sixty-four percent of the patients had bystander cardio-pulmonary resuscitation. An automated external defibrillator (AED) was used in 19% of the patients and the mean time to first defibrillation was 11 +/- 8.9 minutes. Patients being resuscitated and defibrillated by bystanders did better than those who had CPR only and far better than those patients in whom no rescue measures where attempted at all (73% vs. 56% vs. 32% for good neurological outcome, respectively, p= 0.03). Witnessed cardiac arrest was more frequent in patients with a good outcome than in those who collapsed without a witness (91% vs 75%, p = 0.03). In 76% of the patients with good outcome, CPR was performed whereas only 52% benefited from these measures in the bad outcome group (p = 0.01). Although the use of an AED was not significantly different between good and bad outcome groups (26% vs. 11%, p = 0.06), time to first defibrillation was significantly lower in patients with good outcome (8.7 +/- 6.3 vs. 13.3 +/- 11.3 minutes, p = 0.05). In the 17 patients in whom an AED was used, 12 (71%) recovered without major sequelae whereas in the 73 cases where no AED was used, only 34 (47%) had a good outcome (p = 0.06). At 6 months follow-up, 46 (51%) survivors had a good outcome (cerebral performance category 1-2), 5 (6%) survived with severe neurological sequelae or stayed in coma and 39 (43%) died.

CONCLUSIONS

Our local data confirm that early interventions have a major impact on survival of cardiac arrest patients. Efforts should concentrate on delivering rapid and high quality CPR as well as early defibrillation by AED's to every patient in cardiac arrest. Besides large scale Basic life support training, the introduction of dispatcher assisted CPR and the implementation and use of public AED's could considerably help to improve outcome in these patients.

[Antimicrobial resistance monitoring in Lower Saxony (ARMIN): first trends for MRSA, ESBL-producing Escherichia coli and VRE from 2006 to 2010]

Antimicrobial resistance is one of the most important health topics of the past few years. To identify regional trends of antimicrobial resistance in inpatient and outpatient care, the Governmental Institute of Public Health of Lower Saxony (Germany) launched the sentinel system ARMIN (Antimicrobial Resistance Monitoring in Lower Saxony). Currently 9 laboratories participate as sentinel sites and contribute single case data of their microbiological results. Data are presented by an interactive data query in the internet. From 2006 to 2010 laboratories reported about 800 000 diagnostic test results. The proportion of MRSA (methicillin-resistant Staphylococcus aureus) among all Staphylococcus aureus increased from 19.5% in 2006 to 23.4% in 2010 for inpatient care in Lower Saxony. During the same period Escherichia coli resistance to cefotaxime for inpatient care increased from 3.0% to 8.8%. Enterococcus faecium resistance to vancomycin decreased from 13.6% to 5.6%. Currently the emphasis of ARMIN is on the description of trends and on the information of prescribing physicians. A quality circle was established to improve standardisation.

Serum albumin, subjective global assessment, body mass index and the bioimpedance analysis in the assessment of malnutrition in patients up to 15 years after liver transplantation

BACKGROUND

The subjective global assessment (SGA) or the body mass index (BMI) is used to determine the nutritional state after LTX. Bioelectrical impedance analysis (BIA) is used as tool to determine body composition by nutritional care professionals.

METHODS

BIA, SGA, BMI, and serum albumin (SA) levels were performed to assess malnutrition following liver transplantation. BIA measurement was used as reference standard to determine existing malnutrition. A phase angle (PA) <5 was used to define potentially existing chronic disease-related malnutrition as a standard. All other measured parameters were compared with respect to their prognostic accuracy regarding the prediction of malnutrition as compared to the mentioned standard.

RESULTS

Seventy-one recipients (51 men, 20 women) were included. Median age was 58, weight 77 kg, BMI 26 kg/m(2) , PA 4.1°, and SA 4.3 g/dL. According to the Nutritional Risk Screening 2002, 9.4% (6/71), to BMI 15.4% (11/71), to SA 30.9% (22/71), and to BIA 36.5% (28/71) of the patients were malnourished. PA did not correlate with BMI or NA, there was a significant correlation with SA (p = 0.001). Univariate analysis revealed SA as independent predictor for malnutrition. ROC analysis for all parameters revealed a significantly (p < 0.05) better area under the receiver operating characteristic curve for SA (0.812) than for BMI (0.603) for the prediction of malnutrition.

CONCLUSION

SGA or BMI calculation alone does not suffice to evaluate the nutritional status. SA seems to play a crucial role in the prediction of severe disease-related malnutrition in this special patient cohort.

Interferon-γ release assays for the diagnosis of latent Mycobacterium tuberculosis infection: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis to compare the accuracy of the QuantiFERON-TB® Gold In-Tube (QFT-G-IT) and the T-SPOT®.TB assays with the tuberculin skin test (TST) for the diagnosis of latent Mycobacterium tuberculosis infection (LTBI). The Medline, Embase and Cochrane databases were explored for relevant articles in November 2009. Specificities, and negative (NPV) and positive (PPV) predictive values of interferon-γ release assays (IGRAs) and the TST, and the exposure gradient influences on test results among bacille Calmette-Guérin (BCG) vaccinees were evaluated. Specificity of IGRAs varied 98-100%. In immunocompetent adults, NPV for progression to tuberculosis within 2 yrs were 97.8% for T-SPOT®.TB and 99.8% for QFT-G-IT. When test performance of an immunodiagnostic test was not restricted to prior positivity of another test, progression rates to tuberculosis among IGRA-positive individuals followed for 19-24 months varied 8-15%, exceeding those reported for the TST (2-3%). In multivariate analyses, the odd ratios for TST positivity following BCG vaccination varied 3-25, whereas IGRA results remained uninfluenced and IGRA positivity was clearly associated with exposure to contagious tuberculosis cases. IGRAs may have a relative advantage over the TST in detecting LTBI and allow the exclusion of M. tuberculosis infection with higher reliability.

Neuronal correlates of visual and auditory alertness in the DMT and ketamine model of psychosis

Deficits in attentional functions belong to the core cognitive symptoms in schizophrenic patients. Alertness is a nonselective attention component that refers to a state of general readiness that improves stimulus processing and response initiation. The main goal of the present study was to investigate cerebral correlates of alertness in the human 5HT(2A) agonist and N-methyl-D-aspartic acid (NMDA) antagonist model of psychosis. Fourteen healthy volunteers participated in a randomized double-blind, cross-over event-related functional magnetic resonance imaging (fMRI) study with dimethyltryptamine (DMT) and S-ketamine. A target detection task with cued and uncued trials in both the visual and the auditory modality was used. Administration of DMT led to decreased blood oxygenation level-dependent response during performance of an alertness task, particularly in extrastriate regions during visual alerting and in temporal regions during auditory alerting. In general, the effects for the visual modality were more pronounced. In contrast, administration of S-ketamine led to increased cortical activation in the left insula and precentral gyrus in the auditory modality. The results of the present study might deliver more insight into potential differences and overlapping pathomechanisms in schizophrenia. These conclusions must remain preliminary and should be explored by further fMRI studies with schizophrenic patients performing modality-specific alertness tasks.

Torsemide Versus Furosemide After Continuous Renal Replacement Therapy Due to Acute Renal Failure in Cardiac Surgery Patients

Diuretic therapy in ARF (acute renal failure) is mainly done with loop diuretics, first of all furosemide. Torsemide has a longer duration of action and does not accumulate in renal failure. In chronic and acute renal failure, both diuretics have been effectively applied, with a more pronounced diuretic effect for torsemide. In this study, the effects of torsemide versus furosemide on renal function in cardiac surgery patients recovering from ARF after continuous renal replacement therapy (CRRT) were studied. Twenty-nine critically ill patients admitted to an intensive care unit at a university teaching hospital after cardiac surgery recovering from ARF after CRRT were included in this prospective, controlled, single-center, open-labeled, randomized clinical trial. Inclusion criteria were urine output >0.5 mL/kg/h over 6 h under CRRT. Torsemide and furosemide dosages were adjusted with the target urine output being 0.8-1.5 mL/kg/h. Hemodynamic data, urine output, volume balance, serum creatinine clearance, electrolytes, blood urea nitrogen, serum creatinine, renin, and aldosterone concentrations were measured. Fourteen patients were included in the furosemide group and 15 patients in the torsemide group. Dosages of 29 (0-160) mg torsemide and a dosage of 60 (0-240) mg furosemide were given every 6 h in each group, respectively. The dosage given at the end of the study decreased significantly in furosemide and torsemide treated patients. Urine output, 24 h balance, and serum creatinine clearance did not differ significantly between groups. Urine output decreased in both groups, mostly dose-dependent in the torsemide group. The intragroup comparison of the first time-interval after inclusion with the last time-interval showed a significant increase in serum creatinine and blood urea nitrogen in the furosemide group. Renin and aldosterone concentrations did not show significant differences. In conclusion, torsemide and furosemide were effective in increasing urine output. Torsemide might show a better dose-dependent diuretic effect in ARF patients after CRRT treatment. Serum creatinine and blood urea nitrogen elimination were less pronounced in the furosemide group.

[Comparison of the tuberculin skin test with the interferon-gamma test in the framework of a surroundings investigation in a prison]

After the occurrence of a multidrug-resistant tuberculosis in a prison of Lower Saxony (Germany), 223 contact persons (178 inmates, 45 staff members) were identified. To detect latent tuberculosis infections, all contact persons were tested with the tuberculin skin test (TST) and the interferon-gamma release assay (IGRA). An additional standardised questionnaire on anamnestic information and risk factors was completed by the participants. The statistical analysis included 149 male inmates with a mean age of 39 years. 61.1% of the inmates were born in Germany, 14.8% were born in the USSR or, respectively, its follow-up states. With the TST 29.5% of the inmates were tested positive, whereas with the IGRA the positive rate was 18.1%. For 7 inmates there was a positive IGRA despite a negative TST. The positive predictive value of TST with respect to IGRA was 45.5%, agreement was 79.2% (kappa=0.44). The agreement found in this study is comparable to studies within populations with lower incidence. Numerous investigations outside Europe indicate a high risk of tuberculosis infection among inmates.

Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited)

The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110 GHz) to resolve the one-dimensional velocity distribution of the confined fast ions. The steerable antennas will allow different scattering geometries to fully explore the anisotropic fast ion distributions at different spatial locations. This paper covers the capabilities and operational limits of the diagnostic. It then describes the commissioning activities carried out to date. These activities include gyrotron studies, transmission line alignment, and beam pattern measurements in the vacuum vessel. Overlap experiments in near perpendicular and near parallel have confirmed the successful alignment of the system. First results in near perpendicular of scattered spectra in a neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) plasma (minority hydrogen) on ASDEX Upgrade have shown evidence of ICRH heating phase of hydrogen.

[Extensively drug-resistant tuberculosis]

Recently an increasing number of antibiotic-resistant MYCOBACTERIUM TUBERCULOSIS (MTB) strains have been described worldwide. The term XDR- (extensively drug-resistant) tuberculosis (TB) has been introduced by the World Health Organisation (WHO) to characterize multi-drug-resistant MTB strains that are in vitro resistant against fluorochinolones and one of the injectible substances amikacin, capreomycin or kanamycin in addition to isoniazid and rifampin. Strains of XDR-MTB are currently increasingly seen in HIV-seropositive individuals with tuberculosis in southern Africa, where these strains are passed by person-to person contact. XDR-TB has become a serious problem for the health administrations in this region. In contrast, cases of XDR-TB are only rarely seen in Germany so far, mainly among the population of pre-treated migrants from eastern Europe. The development of rapid diagnostic tests for resistance testing and new drugs for the treatment of tuberculosis has lacked support for several decades. The sudden emergence of XDR-MTB strains now warrants immediate action for the development of such tests and new classes of antibiotics to give all patients with TB a chance for a successful treatment.

[Coil embolization of arteriovenous fistulae on in situ saphenous vein bypasses: success rate and complications]

PURPOSE

To determine the success and complication rate of coil embolization of arteriovenous fistulae on in situ saphenous vein bypasses.

MATERIALS AND METHOD

82 AV-fistulae on 30 bypasses (28 patients, 20 men, age 62.5 +/- 8.3 years) were treated using coils. The success rate, complications, duration, amount of contrast material and radiation exposure were measured. Color-coded duplex sonography was performed 1 - 2 days and up to 6 - 18 months after embolization.

RESULTS

The success rate was 68.3 %. The reasons for persistent fistula perfusion were: 96 % fistula not accessible, 4 % reperfusion during thrombolysis. 7 complications were observed in 6 bypasses: failure of placement and retrieving of coil (n = 4), thrombembolic complications with thrombolysis (n = 3). The duration of intervention was 118.3 +/- 46.6 min, the contrast material need was 277.03 +/- 94.0 ml, and the radiation exposure was 10 966 +/- 11 295 cGy/cm (2). Additional balloon dilatation was performed in 30 % of the bypasses. All bypasses were open 1-2 days after intervention. During follow-up, 11 persistent fistulae were detected.

CONCLUSIONS

Coil-embolization of arteriovenous fistulae on saphena magna bypasses proved to be a method with moderate success and complication rates.

Peptostreptococcus ivorii-associated skin abscess in a HIV-infected patient

Peptostreptococcus ivorii, a recently described species of gram-positive anaerobic coccus, has so far rarely been found in human infections. The isolation of this anaerobe from a polybacterial skin abscess in a HIV-infected patient, which formed after antiretroviral therapy had been discontinued is reported. Local treatment led to the abscess healing without specific antibiotics. As the type strain was isolated from a mixed infected leg ulcer, Peptostreptococcus ivorii could play an important role in synergistic infections of the skin.