[Oral Anticoagulants: Management of Elective and Emergency Surgery]

In most patients, oral anticoagulation is performed with vitamin K antagonists (VKA) or non-vitamin K antagonist oral anticoagulants (NOAC). Because of a long half-life, VKA are dosed by measuring INR. In standard cases coagulation tests for NOAC are not necessary; application is performed in a fixed dose. Special coagulation tests like anti-Xa activity (for factor Xa inhibitors: apixaban, edoxaban, rivaroxaban) and diluted thrombin time (for dabigatran) are available. At this time, no cut-off values are validated which show a higher risk of intra- and postoperative bleeding. For elective surgery, VKA are bridged by parenteral anticoagulation (e.g. low molecular weight heparin), NOAC are discontinued perioperative. Also, neuraxial anesthesia techniques can be performed with a proper time interval between last intake of a NOAC and puncture. If required, a transition from NOAC to parenteral anticoagulation can be made. Severe bleeding complications can be treated for VKA and NOAC as well by application of prothrombin complex concentrate. A specific antidote to dabigatran is available.

[Hypercapnic Raised Intracerebral Pressure - Ecmo Therapy Despite Major Intracerebral Haemorrhage]

We report a case of a 29-year-old primigravida asian woman with severe peripartal HELLP-syndrome. During delivery she developed coma. HELLP syndrome, complicated by severe intracerebral hemorrhage was detected. During course of therapy with drainage of intraventricular intracerebral hemorrhage, the patient developed pneumonia followed by severe acute respiratory distress syndrome (ARDS) with critically raised ICP. After 31 days of stabilization by extracorporeal membrane oxygenation (ECMO) and lung protective ventilation the patient was weaned of ECMO therapy. Following a period of 107 days including the weaning of respirator-therapy her neurologic status improved and she was able to follow commands, move upper and lower extremities on request, and recognize her relatives.

Decreased protein binding of moxifloxacin in patients with sepsis?

The mean (SD) unbound fraction of moxifloxacin in plasma from patients with severe sepsis or septic shock was determined by ultrafiltration to 85.5±3.0% (range 81.9 and 91.6%) indicating a decreased protein binding of moxifloxacin in this population compared with the value of 58-60% provided in the Summary of Product Characteristics. However, previous investigations neglected the influence of pH and temperature on the protein binding of moxifloxacin. Maintaining physiological conditions (pH 7.4, 37°C) - as in the present study - the unbound fraction of moxifloxacin in plasma from healthy volunteers was 84%. In contrast, the unbound fraction of moxifloxacin was 77% at 4°C and 66-68% in unbuffered plasma or at pH 8.5 in fair agreement with previously published data. PK/PD parameters e.g. fAUC/MIC or ratios between interstitial fluid and free plasma concentrations, which were obtained assuming a protein binding rate of moxifloxacin of 40% or more, should be revised.

Optical multichannel room temperature magnetic field imaging system for clinical application

Optically pumped magnetometers (OPM) are a very promising alternative to the superconducting quantum interference devices (SQUIDs) used nowadays for Magnetic Field Imaging (MFI), a new method of diagnosis based on the measurement of the magnetic field of the human heart. We present a first measurement combining a multichannel OPM-sensor with an existing MFI-system resulting in a fully functional room temperature MFI-system.

Use of palivizumab in Germany: data from 2002-2007

BACKGROUND

The German Palivizumab Registry refers to a post-marketing observational study of palivizumab administration during 5 consecutive respiratory syncytial virus (RSV) seasons (2002/2003 -2006/2007).

PATIENTS AND METHODS

The registry provided data on drug administration, risk factors for complicated RSV disease, rehospitalisation rates for infants receiving RSV prophylaxis, and parental adherence. 49608 administrations were documented in 10686 patients (average of 4.6 per patient).

RESULTS

35% of infants received >5 monthly injections. Median gestational age at birth was 29 weeks (range 23-41 weeks), median birth weight was 1350 g (range 320-6620 g), 3% were attending day care, 46% lived in a household with children <12 years, 18% were exposed to tobacco smoke at home, 10% had a family history of asthma, and 31% had congenital heart disease. The risk of serious adverse events possibly or probably related to palivizumab administration was 0.2 per 1000 administrations. According to a worst-case calculation, the rehospitalisation rate related to RSV infection was 2.5% in children who received prophylaxis.

CONCLUSION

The German Palivizumab Registry provides a comprehensive dataset describing the use of palivizumab in Germany from 2002 to 2007, and areas for improvement identified in this registry can be applied to enhance the use of palivizumab in the future.

Gastric emptying in patients with insulin dependent diabetes mellitus and bioavailability of thioctic acid-enantiomers

The objective of this study was to determine the impact of prolonged gastric emptying in patients with insulin dependent diabetes mellitus (IDDM) on the bioavailability of the R(+)- and S(-)-thioctic acid (TA) enantiomers. Gastric emptying time (GET) was assessed in 30 healthy volunteers and 22 patients with IDDM using sequential ultrasonography after a standardized solid-liquid test meal. Pharmacokinetics and absolute bioavailability (F) of the TA-enantiomers were studied using a randomized, open two-way crossover design with administrations of oral and intravenous single doses of 200 mg rac-TA. GET in healthy subjects was 134.7+/-21.6 min, the normal range was calculated from 88.3 to 181.1 min. The mean GET in all IDDM patients was significantly prolonged (178.2+/-28.1 min; P<0.001). Only 50% of the patients (n=11) were found to have normal GET (group A), the other half of the population (n=11) were considered to have delayed GET (group B). Mean GET values were 156.9+/-21.5 in group A (P=0.028) and 199.4+/-13.9 min in group B, respectively, suggesting that gastric motility is significantly different from non-diabetic controls even in patients with apparently normal gastric emptying. Times to peak plasma concentrations (t(max)) of both TA-enantiomers were similar in both groups and thus, unrelated to measures of gastric emptying. In contrast, maximum concentrations (C(max)) and area-under-the-curve values (AUC) of both enantiomers were reduced by about 30% in patients with delayed GET. Although these differences resulted in statistical significance for the AUC of both enantiomers (P<0.05), linear regression analysis showed only modest correlation between GET and the extent of TA-enantiomer absorption (r2=0.31 and 0.22 for R(+)-/S(-)-TA, respectively). The study suggests that prolonged gastric emptying is frequently present in IDDM. Delayed gastric emptying, however, does not substantially affect the rate and extent of absorption of both TA-enantiomers.

Fetal MCG and fetal MEG measurements with a 3-channel SQUID system

Since the high costs of common large array SQUID system may hinder widespread application of fetal magnetoencephalography (fMEG) and magnetocardiography (fMCG), we intended to investigate a small non-commercial 3-channel SQUID system. The system comprises 3 axial first order gradiometers with 7 cm base length, 2 cm diameter and 2x2 windings of niobium wire, dc-SQUIDs (UJ-111), and current locked mode SQUID electronics that form an equal length triangle (22.5 mm). The system is mounted in a Cryostat BFH-7 model 16 with 5 mm "warm"-"cold" distance. System noise is about 10 fT/Hz1/2. The fMEG and fMCG were recorded between 29 - 40 weeks of gestation after sonographic localization of the fetal head and heart using a 31-channel biomagnetometer (Philips) and the 3-channel-system, both in the same magnetically shielded room. The fMEG was recorded continuously over 500 sec (500 auditory stimuli, 100 dB SPL, 500 Hz, 50 ms, ISI 0.8-1.2/1.6-2.4 sec, trigger channel, maternal ECG lead, sampling rate 1 kHz). The fMCG was recorded over a period of 5 minutes after dewar readjustment. The detection rates of cortical auditory evoked responses (CAER) reached 100 % for both systems. Cross confirmation of the components was difficult and may have uncovered false positive component detection. The fMCG was characterized by a systematic increase in SNR under application of the smaller device. The small size array provides a profitable alternative for the fetal applications.

Treatment of symptomatic diabetic polyneuropathy with the antioxidant alpha-lipoic acid: a meta-analysis

AIMS

To determine the efficacy and safety of 600 mg of alpha-lipoic acid given intravenously over 3 weeks in diabetic patients with symptomatic polyneuropathy.

METHODS

We searched the database of VIATRIS GmbH, Frankfurt, Germany, for clinical trials of alpha-lipoic acid according to the following prerequisites: randomized, double-masked, placebo-controlled, parallel-group trial using alpha-lipoic acid infusions of 600 mg i.v. per day for 3 weeks, except for weekends, in diabetic patients with positive sensory symptoms of polyneuropathy which were scored by the Total Symptom Score (TSS) in the feet on a daily basis. Four trials (ALADIN I, ALADIN III, SYDNEY, NATHAN II) comprised n=1258 patients (alpha-lipoic acid n=716; placebo n=542) met these eligibility criteria and were included in a meta-analysis based on the intention-to-treat principle. Primary analysis involved a comparison of the differences in TSS from baseline to the end of i.v. Treatment between the groups treated with alpha-lipoic acid or placebo. Secondary analyses included daily changes in TSS, responder rates (> or =50% improvement in TSS), individual TSS components, Neuropathy Impairment Score (NIS), NIS of the lower limbs (NIS-LL), individual NIS-LL components, and the rates of adverse events.

RESULTS

After 3 weeks the relative difference in favour of alpha-lipoic acid vs. placebo was 24.1% (13.5, 33.4) (geometric mean with 95% confidence interval) for TSS and 16.0% (5.7, 25.2) for NIS-LL. The responder rates were 52.7% in patients treated with alpha-lipoic acid and 36.9% in those on placebo (P<0.05). On a daily basis there was a continuous increase in the magnitude of TSS improvement in favour of alpha-lipoic acid vs. placebo which was noted first after 8 days of treatment. Among the individual components of the TSS, pain, burning, and numbness decreased in favour of alpha-lipoic acid compared with placebo, while among the NIS-LL components pin-prick and touch-pressure sensation as well as ankle reflexes were improved in favour of alpha-lipoic acid after 3 weeks. The rates of adverse events did not differ between the groups.

CONCLUSIONS

The results of this meta-analysis provide evidence that treatment with alpha-lipoic acid (600 mg/day i.v.) over 3 weeks is safe and significantly improves both positive neuropathic symptoms and neuropathic deficits to a clinically meaningful degree in diabetic patients with symptomatic polyneuropathy.

Active magnetic shielding for biomagnetic measurement using spatial gradient fields

Biomagnetic measurement performed outside a magnetically shielded room is subject to distortion by strong magnetic fields. Reducing such disturbances can enhance and stabilize biomagnetic measurement conditions in the absence of passive shielding. We have developed an active magnetic shielding system that produces both homogeneous and spatial gradient magnetic fields. The system is composed of anisotropic magnetoresistive sensors, a digital signal processor controller and two different coil systems. In order to improve the measurement environment for a first-order gradient coil SQUID system, the disturbing vertical magnetic fields and vertical field gradients are reduced, thus achieving a shielding factor of approximately 6 at 100 Hz. Our system provides a more flexible and less costly alternative to magnetically shielded rooms.

[Ductal carcinomas in situ]

EPIDEMIOLOGY

Presently representing 15 to 30% of new cases of breast cancer, ductal carcinomas in situ do not have specific epidemiological characteristics. The age at which they occur is between 49 and 54 years.

DIAGNOSTIC METHODS

The diagnosis is evoked primarily when confronted with an area of micro-calcifications discovered on a mammography. Needle aspiration cytology, useful in cases of palpable abnormalities or infra-clinical masses, is of no interest in isolated micro-calcifications for which surgical biopsy following radiological localisation is the technique of choice. Needle micro-biopsy permits collecting analysable tissue for histological but not cytological examination. Macro-biopsies combine stereotaxic localisation of micro-calcification areas and their excision when isolated. The choice of the method varies depending on the case.

FROM AN ANATOMOPATHOLOGICAL POINT OF VIEW

Ductal or intra-galactophoric carcinomas are carcinomas of the glactophores that do not infiltrate the connective tissue. They are defined histologically by architectural and cytological characteristics, which differentiate them from lobular carcinomas in situ. They constitute a group of heterogenic lesions not only morphologically but also histologically and with regard to their progression.

THERAPEUTIC MODALITIES

The aim of treatment is to ensure that the patients have a maximum of chances of cure at the cost of the least possible therapeutic consequences. Mastectomy, treatment of choice for many years, is still recommended in certain situations. In other cases, conservative treatment is possible so long as excision of the micro-calcifications is complete on the post-surgical mammography and, in the case of biopsy excision, that healthy margins of at least 10 millimetres exist. Following surgery, there is no sufficient consensus to propose essential recommendations concerning the place of monitoring alone, irradiation or tamoxifen.

Sensitive magnetic sensors without cooling in biomedical engineering

Magnetic field sensors are used in various fields of technology. In the past few years a large variety of magnetic field sensors has been established and the performance of these sensors has been improved enormously. In this review article all recent developments in the area of sensitive magnetic field sensory analysis (resolution better than 1 nT) are presented and examined regarding their parameters. This is mainly done under the aspect of application fields in biomedical engineering. A comparison of all commercial and available sensitive magnetic field sensors shows current and prospective ranges of application.

High frequency intra-QRS signals in idiopathic dilated cardiomyopathy

We extracted and quantified high frequency intra-QRS signals in idiopathic dilated cardiomyopathy (IDC). In IDC the analysis of late potentials in the terminal QRS complex often fails in predicting clinical events because of intraventricular conduction abnormalities and the absence of a circumscribed arrhythmogenic substrate. Therefore, new approaches are required to assess the electrical state of the myocardium. We investigated 21 patients suffering from IDC with (n = 14) and without (n = 7) bundle branch block. High resolution 31 lead magnetocardiograms were filtered with a 67 point 4th order Savitzky-Golay filter. The difference of the measured and filtered signals was calculated (67-200 Hz). The spatio-temporal properties and the areas under the curves of the resulting high frequency intra-QRS signals (IQCs) were studied. We detected IQCs in all patients. The patients had individual patterns regarding the temporal and spatial properties of the IQCs during depolarisation. The IQCs predominantly appeared in the initial portion of the QRS. The ratios of the areas under the curves of the IQCs and the measured signals were linearly correlated to the left ventricular enddiastolic diameter (r = 0.71, significance 0.0012). In IDC the ventricular depolarization is accompanied by individual spatial and temporal patterns of high frequency intra-QRS signals. They can be studied non-invasively from body surface mapping data with the algorithm used in this study. This provides access to the assessment of the electrical status in patients with IDC.

Signal analysis of auditory evoked cortical fields in fetal magnetoencephalography

Magnetoencephalography (MEG) using auditory evoked cortical fields (AEF) is an absolutely non-invasive method of passive measurement which utilizes magnetic fields caused by specific cortical activity. By applying the exceptionally sensitive SQUID technology to record these fields of dipolar configuration produced by the fetal brain, MEG as an investigational tool could provide new insights into the development of the human brain in utero. The major constraint to this application is a very low signal-to-noise ratio (SNR) that has to be attributed to a variety of factors including the magnetic signals generated by the fetal and maternal hearts which inevitably obscure a straightforward signal analysis. By applying a new algorithm of specific heart artefact reduction based on the relative regularity of the heart signals, we were able to increase the chance of extracting a fetal AEF from the raw data by the means of averaging techniques and principle component analysis. Results from 27 pregnant, healthy women (third trimester of their uncomplicated pregnancy) indicate an improved detection rate and the reproducibility of the fetal MEG. We evaluate and discuss a-priori criteria for signal analyses which will enable us to systematically analyze additional limiting factors, to further enhance the efficiency of this method and to promote the assessment of its possible clinical value in the future.

Effect of ketamine on the neuromagnetic mismatch field in healthy humans

Mismatch negativity (MMN) is a component of the auditory evoked event-related potentials (ERP) that assesses automatic sound change detection and is disturbed in schizophrenic patients. Animal experimental evidence has linked the generation of MMN to the N-methyl-D-aspartate (NMDA) receptor. We investigated the neuromagnetic mismatch field (MMF) in healthy volunteers before and after intravenous application of a subanesthetic dose of the NMDA receptor antagonist ketamine (0.3 mg/kg). Ketamine had a significant influence on latency and dipole moment of the MMF, whereas the N100m latency of the standard tone was not prolonged and its dipole moment remained stable. Our results suggest that ketamine interferes with aspects of preattentive information processing and is in line with the view that disturbed NMDA receptor function may mediate the deficient auditory mismatch response in patients with schizophrenia.

Localization of late potential sources in myocardial infarction

INTRODUCTION

Late potentials (LP) are markers of arrhythmogenic events after myocardial infarction (MI). The localization of LP sources would help to identify arrhythmogenic myocardium. The purpose of this study was to localize these LP sources from non-invasive body surface mapping data.

METHODS AND RESULTS

Six patients were investigated with cardiac MRI and signal averaged 62-lead magnetocardiography after MI. Three of them were suffering from sustained ventricular tachycardia (VT). Sophisticated computer algorithms were used in order to compute the current density on the surface of the left ventricle. We compared these current density distributions for the entire QRS complex and the high frequency LP signals. In the three patients which had premature ventricular complexes (PVCs) we localized the exit sites of these arrhythmias. We found a close matching of the low current density areas based on the QRS complexes and the high current density areas based on the LP signals. These areas predominantly corresponded to sites of the infarctions. Exit sites of PVCs were located close to these areas.

CONCLUSIONS

By means of sophisticated computer algorithms we were able to localize LP sources. This would be useful in steering catheter ablation and coronary revascularization therapies. However, the method has to be proven with the help of invasive mapping in a larger number of patients.

The application of fetal magnetocardiography (FMCG) to investigate fetal arrhythmias and congenital heart defects (CHD)

OBJECTIVES

Fetal magnetocardiography (FMCG), a new non-invasive diagnostic tool in the analysis of the electrophysiological changes of the heart, was selectively applied in cases of fetal arrhythmias and congenital heart defect (CHD) to demonstrate its value for diagnosis and prenatal management.

METHODS

The FMCG was analysed and compared to the postnatal ECG in four cases of fetal arrhythmia [supraventricular tachycardia (two cases), complex tachy-/bradycardia (one case), ventricular extrasystoles (one case)] and a case of right heart hypoplasia diagnosed by established methods prior to investigation.

RESULTS

A Wolf-Parkinson-White (WPW) syndrome was diagnosed by its characteristic features and the appropriate transplacental therapy chosen. The types of arrhythmia could be characterised in accordance with postnatal ECG findings and irregular conduction was demonstrated in association with a CHD.

CONCLUSIONS

The use of the FMCG provides additional information to the common diagnostic tools that influence therapeutic decisions and thus contributes to optimal pre- and postnatal management.

Passive finger movement evoked fields in magnetoencephalography

We studied neuromagnetic fields during passive finger movements in 11 normal subjects. Activation started 27 ms after the onset of movement and remained for about 100 ms. Four activation maxima occurred within this time range, PM1 at 27 ms, PM2 at 46 ms, PM3 at 85 ms, and PM4 at 125 ms. Not all components were distinguishable in every subject partly due to overlapping effects, but PM3 was present in all subjects. Magnetic source imaging (MSI) revealed dipolar sources within 1 cm of the central sulcus for all four components. The results suggest that studying the integrity of the sensorimotor system in patients regardless of their degree of motor impairment is feasible.