Sichere Lagekontrolle von Magensonden: ein oft unterschätztes Thema zur Vermeidung potenziell schwerwiegender Komplikationen

Die Anaesthesiologie - Die Anlage einer Magensonde im OP oder auf einer Intensivstation (ITS) stellt eine alltäglich durchgeführte Prozedur dar. Obwohl die Sonde häufig durch...     

Optical non-invasive technique for vessel imaging: I. Experimental results

This paper investigates some prerequisites for vessel imaging based on diffuse reflectance measurements in order to develop an optical non-invasive method for the imaging and monitoring of vessels. The method utilizes near-infrared (NIR) radiation (890 nm) from a light emitting diode. The light is guided into the tissue via an optical fibre (diameter 1.0 mm). The backscattered light is collected by an optical fibre of the same type and detected by an optical power meter. The fibres are moved over the skin in two directions with the aid of two motors operated by a microcomputer. Spatially resolved reflectance at the skin surface could be presented as a vessel-map in a colour-coded form on a computer screen. Experimental results indicate that the vessel imaging facility depends upon source-detector separation, relative position and vessel depth, and does not depend essentially on the radiant power from the light source. It is shown that, by a proper choice of probe parameters, one can improve the vessel identification ability. After vessel imaging the technique can potentially be used to monitor several physiological parameters on a selected vascular bed or to distinguish between injured and healthy tissue by monitoring local blood flow, oxygen saturation and the recirculation, pre- and post-operatively.     

Structural and steric requirements for β-phenethylamines as agonists of the noradrenergic cyclic AMP generating system in the rat limbic forebrain

Summary The present studies were undertaken to assess the structural and steric requirements for -phenethylamines as agonists of the noradrenergic cyclic AMP generating system in slices of the rat limbic forebrain. Significant agonist activity of -phenethylamines requires a -3,4-dihydroxyphenethylamine with a -hydroxyl group in the R configuration. Thus, dopamine did not stimulate the system at concentrations up to 10^–3 M. Moreover, -hydroxyphenethylamines without a 3,4-catechol group (octopamine, phenylephrine, p-hydroxynorephedrine, metaraminol and methoxamine)-though exerting -agonist activity in peripheral tissues-lack agonist activity in this particular cyclic AMP generating system. The effects of (R)-norepinephrine and (R)-isoproterenol at maximal concentrations were not additive. The results lend further support to the view that the cyclic AMP generating system in slices of the limbic forebrain is part of a norepinephrine receptor coupled adenylate cyclase system with a subpopulation of receptors that are in nature.     

Modification of the noradrenergic cyclic AMP generating system in the rat limbic forebrain by amphetamine: Role of its hydroxylated metabolites

Summary The cyclic AMP responses to norepinephrine (NE) in slices of the rat limbic forebrain after the administration of (S)-amphetamine and the role of its para- and -hydroxylated metabolites were investigated. The chronic but not acute administration of (S)-amphetamine to rats causes a significant reduction in the sensitivity of the cyclic AMP generating system to NE without changing the basal level of the nucleotide. This change in the sensitivity of the system is not associated with a change in the EC₅₀ value for NE but reflects mainly a decrease in the maximal response. After withdrawal of the drug, the cyclic AMP response to NE returned to control values within 4 days. In vitro, (S)-p-hydroxyamphetamine (POH) and all stereoisomers of p-hydroxynorephedrine (PHN) except (S,R)-PHN enhanced the cyclic AMP response to low concentrations of NE. Since (S,R)-PHN [like the other stereoisomers of PHN and (S)-POH] inhibited in a dose-dependent manner the high affinity uptake of ³H-NE into crude synaptosomal fractions of the limbic forebrain, the results might suggest that the presumably physiological enantiomer of PHN also exerts receptor blocking properties. The inhibition by (S,R)-PHN of the cocaine induced potentiation of the cyclic AMP response to NE supports this supposition. The results provide evidence that the hydroxylated metabolites of (S)-amphetamine, (S)-POH and (S,R)-PHN, modify the action of the parent drug on central noradrenergic function at the level of the NE receptor coupled adenylate cyclase system.     

Pelvic Lymph Node Dissection During Robot-assisted Radical Prostatectomy: Efficacy,Limitations, and Complications—A Systematic Review of the Literature

Context

Pelvic lymph node dissection (PLND) in prostate cancer is the most effective method for detecting lymph node metastases. However, a decline in the rate of PLND during radical prostatectomy (RP) has been noted. This is likely the result of prostate cancer stage migration in the prostate-specific antigen-screening era, and the introduction of minimally invasive approaches such as robot-assisted radical prostatectomy (RARP).

Objective

To assess the efficacy, limitations, and complications of PLND during RARP.

Evidence acquisition

A review of the literature was performed using the Medline, Scopus, and Web of Science databases with no restriction of language from January 1990 to December 2012. The literature search used the following terms: prostate cancer, radical prostatectomy, robot-assisted, and lymph node dissection.

Evidence synthesis

The median value of nodal yield at PLND during RARP ranged from 3 to 24 nodes. As seen in open and laparoscopic RP series, the lymph node positivity rate increased with the extent of dissection during RARP. Overall, PLND-only related complications are rare. The most frequent complication after PLND is symptomatic pelvic lymphocele, with occurrence ranging from 0% to 8% of cases. The rate of PLND-associated grade 3–4 complications ranged from 0% to 5%. PLND is associated with increased operative time. Available data suggest equivalence of PLND between RARP and other surgical approaches in terms of nodal yield, node positivity, and intraoperative and postoperative complications.

Conclusions

PLND during RARP can be performed effectively and safely. The overall number of nodes removed, the likelihood of node positivity, and the types and rates of complications of PLND are similar to pure laparoscopic and open retropubic procedures.     

Optical non-invasive technique for vessel imaging: II. A simplified photon diffusion analysis

The purpose of this paper is to explain theoretically the origin of previously presented experimental results by an optical non-invasive method using NIR for imaging blood vessels based on a specific combination of several physical parameters. The theoretical model is based on the diffusion approximation derived from the transport theory deep in a bulk tissue. An analytical solution was obtained describing photon behaviour under certain conditions during vessel identification. The modelled results indicate that the vessel identification facility depends upon source-detector separation and vessel depth, and does not depend essentially on the radiant power from the light source. The solution offers a relatively simple theoretical explanation of the experimental results and can be applied to several other clinical applications using similar technical solutions.     

Ergebnisse der bundesweiten Datenerhebung über die urologische Laparoskopie

To evaluate the current status of laparoscopy, the "Working Group Laparoscopy" of the German Urological Association performed a questionnaire among urologists in Germany. Of 300 questionnaires 183 were returned and analyzed (61%): 54% of the departments already performed laparoscopy and another 50% are planning to introduce this technique. The major concerns are economical (70%), long learning curve (92%), investment (53%), and lack of scientific data (76%). Simple nephrectomy, cryptorchism, and varicoceles are treated by 66, 59, and 58 of the 96 departments laparoscopically (of 183 resp.). Laparoscopic surgery for radical prostatectomy and tumor nephrectomy is done by 32 and 34 of 96 departments. Only a minority of the centers performs more than 40 laparoscopies per year and indication. Compared to a survey conducted in 1995, the acceptance level of this technique has increased (100% vs 48%). Only a minority of the departments performs more than 40 laparoscopic interventions per year for one indication.     

The relative role of dopamine and norepinephrine receptor blockade in the action of antipsychotic drugs: Metoclopramide,thiethylperazine, and molindone as pharmacological tools

The aim of the present studies was to further delineate the role of striatal and limbic dopaminergic versus limbic noradrenergic blockade in the pharmacologic and perhaps therapeutic action of antipsychotic drugs. Metoclopramide shares many properties of antipsychotic neuroleptic drugs, including the production of extrapyramidal side effects, but is not an efficacious antipsychotic agent. This drug was a potent blocker of dopamine (DA) receptors in both striatum and limbic forebrain (comparable in potency to that of chlorpromazine) as evidenced from the increase in homovanillic acid in both brain structures. In contrast, metoclopramide was a weak inhibitor of the norepinephrine (NE) receptor-coupled adenylate cyclase system in the limbic forebrain. Molindone, which is reported not to block DA-sensitive adenylate cyclase, was a potent in vivo blocker of DA receptors in both striatum and limbic forebrain and also inhibited markedly the cyclic AMP response to NE in the limbic forebrain. The phenothiazine derivative, thiethylperazine, was also a potent blocker of DA receptors in both brain areas and displayed an IC₅₀ for NE blockade in the limbic forebrain comparable to that of chlorpromazine. The present results support the view that the ability and potency of drugs to block DA receptors parallels their ability and potency to cause extrapyramidal symptoms in man. Moreover, these results suggest that the blockade of NE receptor-coupled adenylate cyclase systems in brain may be relevant to both the pharmacologic and therapeutic activity of antipsychotic drugs.