Automated external defibrillator use for in-hospital emergency management.

The in-hospital spread of automated external defibrillators (AEDs) is aimed to allow for a shock-delivery within three minutes. However, it has to be questioned if the implementation of AED alone really contributes to a 'heart-safe hospital'. We performed a cohort study of 1008 in-hospital emergency calls in a university tertiary care hospital, analysing cardiopulmonary resuscitation (CPR) cases with and without AED use. In total, 484 patients (48%) had cardiac arrest and received CPR. Response time of the emergency team was 4.3 ± 4.0 minutes. Only 8% percent of the CPR cases had a shockable rhythm. In three of 43 placements a shock was delivered by the AED. There were no differences in survival between patients with CPR only and CPR with AED use. Our data do not support the use of an AED for in-hospital CPR if a professional response team is rapidly available.

[Hepatorenal syndrome]. / Hepatorenales Syndrom.

Hepatorenal syndrome (HRS) is a unique form of acute renal failure occurring in patients with advanced cirrhosis or acute liver failure. In patients with ascites the incidence of HRS is 8 % and in end-stage liver disease 75 % of patients suffer from HRS. Vasodilation of splanchnic arteries with subsequent decrease of effective blood volume, arterial pressure and renal vasoconstriction is hypothesized to be the central pathophysiological mechanism leading to acute renal failure. Moreover, cardiac output might be decreased in advanced cirrhosis. There are two types of HRS: while HRS type 1 is characterized by a rapid progression to acute renal failure often triggered by a precipitating event, e. g. bacterial peritonitis, which can rapidly develop into multiorgan failure, HRS type 2 shows a more steadily or slowly progressive course to renal failure with increasing ascites. Type 1 HRS has the worst prognosis. Treatment options include pharmacological treatment with vasoconstrictors and albumin and placement of transjugular intrahepatic portosystemic shunts (TIPS) but can only partially improve the survival rate. Liver transplantation is the ultimate and only definitive treatment of patients with HRS.

Pharmacokinetics and clinical toxicity of prilocaine and ropivacaine following combined drug administration in brachial plexus anesthesia.

OBJECTIVE: Local anesthetics (LA) are often administered in combination for regional anesthesia in order to obtain the specific advantages (onset and duration of effect) of each drug. However, few data on the safety of such combinations are available and consequently plasma concentrations possibly associated with toxicity and interactions between the specific anesthetics are not sufficiently established. We measured pharmacokinetics and toxicity parameters of prilocaine and ropivacaine after combined use as single doses in brachial plexus blockade. METHODS: In an open clinical study using a combined dose regime (300 mg prilocaine followed immediately by 75 mg ropivacaine) total plasma concentrations of prilocaine and ropivacaine were measured serially in 60 patients using a gas-chromatographic method. The data were analyzed regarding a relationship with central nervous and cardiovascular toxicity. RESULTS: Following the administration in combination prilocaine and ropivacaine were rapidly absorbed. Mean prilocaine peak plasma concentrations (mean Cmax = 1.51 microg/ml) were measured between 15 and 30 min after injection. Highest ropivacaine plasma concentrations (mean Cmax = 1.12 microg/ml) were seen between 30 min and 1 hour after injection (calculated mean tmax = 44 min). One of 59 patients showed signs of myoclonus which were suspected of being due to intravascular injection. There was no relevant cardiovascular toxicity observed in terms of changes in the QRS complex, PQ interval prolongation, AV dissociation, occurrence of extrasystoles or sinus arrest. The pharmacokinetics of combined administration did not differ from those of prilocaine and ropivacaine given alone. CONCLUSION: The use of a combined prilocaine/ ropivacaine (300 mg/75 mg) dose regimen in patients given single dose for brachial plexus blockade can generally be regarded as safe with regard to peak plasma concentrations and cardiovascular toxicity and this holds true for patients with a higher perioperative risk profile (ASA III grading, American Society of Anesthesiologists). The considerable inter-individual variation in LA peak plasma concentrations observed in our patients and the one case of suspected accidental intravascular injection, highlight the necessity of adequate monitoring of the patients undergoing LA injections.

Total dura substitute in the spine: double layer dural substitute made from polylactide layer and bovine pericardium.

When there is significant loss of spinal dura mater, dural substitution with synthetic or allogenic materials is essential. In the case of laminectomy, mechanical protection and reformation of the dorsal spinal canal may be useful. This is a report on a patient with total dura loss through tumour atrophy of the dura and laminae. In order to reconstruct the dorsal face of the spinal canal a polylactide sheet was cut and shaped to fit the physiological contour. A bovine dura substitute was firmly attached and sutured to the inner surface of the polylactide shield. The implant was wedged in between the pedicles and the facet joints and resulted in a water-tight dura substitute maintaining the shape of the spinal canal and protecting it against mechanical forces and intradural scar formation.

Anaesthesia and cardiac contractility modulation.

Chronic heart failure is known to be an important risk factor for adverse perioperative outcome in patients undergoing non-cardiac surgery. A promising new form of electric therapy is currently being used in a phase III trial in patients with severe chronic heart failure (cardiac contractility modulation). Cardiac contractility modulation is a non-pharmacological approach to improve Ca2+ effect on cardiac myofilaments using electric currents. The cardiac contractility modulation system used at present (OPTIMIZER III, Impulse Dynamics, Orangeburg, NY, USA) consists of a subcutaneously implanted pulse generator and three electrodes. As far as we know, cardiac contractility modulation therapy is a safe and feasible way of improving the systolic function of the heart in congestive heart failure patients. No pro-arrhythmic effects of this new therapy have been reported. The technique shows promise as an additive treatment for severe chronic heart failure. The perioperative and intraoperative management of patients should follow current cardiac pacemaker/implantable cardioverter defibrillator guidelines.

Auto fluorescence of intervertebral disc tissue: a new diagnostic tool.

The paper reports on auto fluorescence phenomena of inter-vertebral human discs. It systematically investigates the auto fluorescence effects of ex vivo disc specimen and reports on surgical cases to demonstrate the potential value of the new method. The paper offers biologic explanations of the phenomenon and discusses the potential value of the UV auto fluorescence technique as a diagnostic tool. Intra- and postoperative observations are made by a surgical microscope with an integrated UV light source. Quantitative measurements were carried out using a photon counter and a spectrometer ex vivo. The auto fluorescence phenomenon allows the differentiation of traumatized and degenerated disc tissue intraoperatively in some cases, it allows the differentiation of bony and collagen endplate in cervical disc surgery. The source of the auto fluorescent light emission are amino acids of the collagen molecules. The proteoglycan components and the liquid components of the disc do not show relevant auto fluorescence. Emission wavelength of disc material is equivalent to color perception. It differs due to different collagen composition of the intervertebral disc components from yellow-green to blue-green and can be visualized in situ by naked eye.UV-auto fluorescence of inter-vertebral discs is a new clinical tool that has the potential to differentiate disc material from the anatomical surrounding, to distinguish between different fractions of the disc and to give information on the quality and status of the disc material. Since the technology has just emerged, it needs further investigations to quantify the clinical observations reported in this paper.

Electromyographic investigation on handling forces of mechanically counterbalanced and sensor-servomotor-supported surgical microscopes.

BACKGROUND: Recent developments in sensor-servomotor-driven microscopes again initiated a discussion on the value of such technology for practical use in neurosurgery. The need for less force in moving a motor-supported microscope is advantageous. However, questions remain if well-known difficulties in the past such as resonance phenomenon, loss of natural feeling, and unequal handling forces in different situations have been overcome by the new generation of sensor-servo-supported surgical microscopes. METHODS: Handling forces of a mechanically counterbalanced neurosurgical microscope (Zeiss NC4, Zeiss, Oberkochen, Germany) were compared with those of a sensor-servo-supported neurosurgical microscope (Moeller HiR 20-1000, Moeller, Wedel, Germany). Handling forces were correlated with the surface electromyogram measurement of the muscle activity of 4 neurosurgeons. The activity of the forearm muscles was measured while handling the 2 different microscopes in standardized tests. RESULTS: The electrophysiologic measurement revealed that significantly less muscle activity was required to handle the sensor-servo-driven microscope in all directions. The untrained surgeons profited less than the skilled ones. Differences were most evident with disbalanced microscopes. CONCLUSIONS: With this technology, the neurosurgeons exerted less effort, especially in strenuous test situations where the single-handed use of the microscope was mandatory. The reduced muscle forces that move the sensor-servo-type microscope and the continuously balanced state that might help prevent unwanted correction movements will ease intraoperative handling in general.

Changes in monocytic expression of aminopeptidase N/CD13 after major trauma.

HLA-DR expression on monocytes as marker for monocytic function is severely depressed after major trauma. The membrane enzyme aminopeptidase N/CD13 can trigger help in antigen processing by MHC class II molecules of antigen-presenting cells. We determined the simultaneous expression of HLA-DR and CD13 on peripheral blood monocytes of patients with major trauma (injury severity score of > or =16). 1 : 1 conjugates of phycoerythrin (PE)-to-monoclonal antibody were used in combination with QuantiBRITE PE beads for a standardized quantification in terms of antibodies bound per cell (ABC). The very low expression of HLA-DR antigen on monocytes of patients at day 1 after major trauma confirmed previous results in the literature. Monocytic HLA-DR expression increased slowly to reach values in the lower range of healthy volunteers at day 14. Monocytic CD13 expression at day 1 showed values in the range of healthy volunteers, and a strong rise afterwards. Fourteen days after trauma, the monocytic expression of CD13 was still much higher than in the control group. Because lipopolysaccharide (LPS) and the anti-inflammatory cytokine interleukin (IL)-10 have been shown to be involved in the depressed HLA-DR expression on monocytes in trauma patients, we studied the in vitro effects of LPS and interleukin (IL)-10 on the expression of CD13 on monocytes prepared from the peripheral blood of healthy volunteers. Whereas a 3-day IL-10 treatment resulted in a down-regulation of both HLA-DR and CD13 expression on monocytes, LPS caused a down-regulation of HLA-DR but a rapid up-regulation of CD13 levels. Therefore we suggest that, with respect to monocytic CD13 expression, LPS rather than IL-10 could well be the explanation for monocytic surface molecules after severe injury, although other mediators with a CD13 regulating function have to be considered.