Regional block and DVT prophylaxis

The last few years have seen increasing concerns among anaesthetistsabout the risks of pharmacological prophylaxis for thromboembolicdisease. Increased bleeding during or after surgery is one concern,but of greater significance is the possibility of an increasedpredisposition to haematoma formation when regional block isused. Most of the recent consideration of this problem has beenin relation to vertebral canal haematoma formation after centralnerve block. Some thought must be given also to the possibilityof haematoma formation after peripheral techniques when thetarget nerve is deeply placed so that pressure cannot be usedto control bleeding after needle insertion. However, this reviewwill be focused on vertebral canal haematoma.     

Diisocyanates and nonoccupational disease: a review

More than 32 million people in the United States suffer from chronic lung diseases; 12 million experienced at least one asthma attack in 2002. The causes of this "epidemic" are complex and uncertain; however, there is a strong possibility that environmental exposures play a role. The most common and well-studied cause of occupational asthma is diisocyanates, but their use in consumer products as a potential cause of respiratory disease in the general population has been overlooked. These substances are found in or are used to produce an array of polyurethane-containing products, including adhesives, sealants, paints, flexible foams, and rigid foams, among others. The world market for polyurethane products has tripled since 1985 to more than 9.3 billion kg in the year 2000. In this article, the author reviews biologically plausible explanations, as well as the epidemiologic, experimental, and clinical evidence for the role of diisocyanates and polyurethanes in the genesis of nonoccupational allergy and respiratory disease.     

Limitations of current risk-adjustment models in the era of coronary stenting

Background Several risk-adjustment models have been developed to compare outcomes of conventional coronary angioplasty across physicians and institutions. Yet the accuracy of these models in contemporary interventional practice—characterized by the widespread use of stents and novel adjuvant pharmacotherapies—has not been sufficiently studied. Methods The principal published predictive models for inhospital mortality after angioplasty were validated in 11,681 patients undergoing coronary stenting and 6475 patients undergoing balloon-only procedures in the Society for Cardiac Angiography and Interventions registry from July 1996 to December 1998. We examined the 2 components of model accuracy: discrimination, as determined by the c-index; and calibration, as measured by the Hosmer-Lemeshow statistic and predicted-versus-observed probability plots. Results The discriminative properties of the models were preserved in the validation cohort and did not differ statistically from one another (c-indexes 0.85-0.89). Hosmer-Lemeshow statistics, however, showed poor fit (P < .001), with all 3 models substantially overestimating the risk of adverse outcomes. Although recalibration of the models achieved satisfactory goodness of fit, laboratory-specific ratings differed depending on the model applied. Conclusions Predictive models developed in the era of conventional angioplasty cannot be applied directly to current interventional practice. Although recalibration restores model fit, application of different recalibrated models yields inconsistent assessment of laboratory performance. Development of new, widely generalizable models is warranted, but such models will require continued reassessment as medical technology evolves and practice patterns change. (Am Heart J 2003;145:683-92.)     

Apolipoprotein E genotyping as a potential biomarker for mercury neurotoxicity

Apolipoprotein-E (apo-E) genotyping has been investigated as an indicator of susceptibility to heavy metal (i.e., lead) neurotoxicity. Moreover, the apo-E epsilon (epsilon)4 allele is a major risk factor for neurodegenerative conditions, including Alzheimer's disease (AD). A theoretical biochemical basis for this risk factor is discussed herein, supported by data from 400 patients with presumptive mercury-related neuro-psychiatric symptoms and in whom apo-E determinations were made. A statistically relevant shift toward the at-risk apo-E epsilon4 groups was found in the patients p<0.001). The patients possessed a mean of 13.7 dental amalgam fillings and 31.5 amalgam surfaces. This far exceeds the number capable of producing the maximum identified tolerable daily intake of mercury from amalgam. The clinical diagnosis and proof of chronic low-level mercury toxicity has been difficult due to the non-specific nature of the symptoms and signs. Dental amalgam is the greatest source of mercury in the general population and brain, blood and urine mercury levels increase correspondingly with the number of amalgams and amalgam surfaces in the mouth. Confirmation of an elevated body burden of mercury can be made by measuring urinary mercury, after provocation with 2,3,-dimercapto-propane sulfonate (DMPS) and this was measured in 150 patients. Apo-E genotyping warrants investigation as a clinically useful biomarker for those at increased risk of neuropathology, including AD, when subjected to long-term mercury exposures. Additionally, when clinical findings suggest adverse effects of chronic mercury exposure, a DMPS urine mercury challenge appears to be a simple, inexpensive procedure that provides objective confirmatory evidence. An opportunity could now exist for primary health practitioners to help identify those at greater risk and possibly forestall subsequent neurological deterioration.     

Ultrasound-guided neuronavigation of deep-seated cavernous haemangiomas: clinical results and navigation techniques

The aim of this study was to evaluate guidance techniques and patient outcomes of ultrasound-guided neuronavigation of deep-seated intracerebral cavernous hemangiomas (CAs). Thirty-five patients with deep-seated intracerebral CAs with sizes ranging between 7 and 45 mm were operated upon only with ultrasound-guidance. Twenty-seven were located in or near eloquent regions. In 30 patients dissection to the lesion was performed through sulci and fissures. The best approach to a lesion based on surface anatomy and depth was determined using sonographic information. Navigation was done sonographically. In five patients the shortest approach via a corticotomy was determined sonographically. Twenty-six patients had no neurological deficit postoperatively. Preoperative deficits improved in seven of nine patients. Fifteen of 19 patients suffering epileptic seizures had no seizures postoperatively. Intraoperative sonography revealed residual CA tissue after microsurgical extirpation in two cases. This report shows that intraoperative sonographic navigation provides safe guidance to deep-seated CAs with good clinical outcome independent of size.     

Heavy metals in soft tissue of white-tailed eagles found dead or moribund in Germany and Austria from 1993 to 2000

Residues of the potentially toxic metals lead, mercury, and cadmium were analyzed in liver and kidney tissue of 61 free-ranging white-tailed eagles (Haliaeetus albicilla) found dead or moribund in Germany and Austria between 1993 and 2000. Highest values and the widest range were detected for lead in liver and for mercury in kidney tissue. Lead concentrations considered to induce lethal lead poisoning (>5 ppm wet wt) were determined in 28% of liver samples. Lead fragments were detected it the gizzards of two specimens, presumably having died from lead intoxication. Histopathological findings in a recently dead white-tailed eagle indicating acute lead exposure comprise degenerative Purkinje cells in the cerebrellum and inclusion bodies in renal tubular cells. Mercury residues in organs are decreasing compared to former studies in periods when organomercury compounds were used as seed dressing. All cadmium values were low or are at background levels in white-tailed eagles. The present study clearly identities lead as a toxic metal poison in white-tailed eagles in Germany and Austria.