ENTERAL VERSUS PARENTERAL NUTRITION AFTER OESOPHAGOGASTRIC SURGERY: A PROSPECTIVE RANDOMIZED COMPARISON

Background: There appears to be an emerging consensus that early postoperative nutritional support benefits the high-risk patient by decreasing septic morbidity, maintaining immunocompetence and improving wound healing. Enteral nutrition via a feeding jejunostomy has been associated with serious complications, with a reported mortality rate as high as 10%. while total parenteral nutrition has also been associated with a wide variety of complications. Methods: Ninety-seven patients undergoing oesophagectomy or gastrectomy underwent pre-operative nutritional assessment and were randomized to receive either total parenteral nutrition (47 patients) or enteral nutrition (50 patients). Results: There was no significant difference in the number of catheter-related complications between the two groups, but 9 (45%) patients in the total parenteral nutrition group had major morbidity (potentially fatal in two patients) requiring active intervention. Conclusions: This study demonstrates enteral nutrition to be safe and associated with mainly reversible minor complications. It is probable that immediate postoperative enteral feeding conserves the gut's integrity. Whether this leads to a reduction in postoperative septic complications has not been demonstrated by this study although there appears to be a trend in this direction, supporting the concept of enteral feeding as ‘primary therapy’. This can be safely, simply and economically achieved using a feeding jejunostomy placed at the time of surgery.     

Consequences of misfilling contemporary vaporizers with desflurane

Desflurane is a volatile anaesthetic that combines low blood gas solubility (blood/gas partition coefficient =0.42 at 37° C), moderate potency (MAC = 6–7%), and high volatility (vapour pressure =681 mmHg at 20° C, boiling point = 23.5° C). The volatility and potency of desflurane prevent its safe use in vaporizers of traditional design. We present a mathematical model which demonstrates the potential for desflurane overdose if contemporary vaporizers are misfilled with desflurane. The most hazardous filling error occurs if an enflurane vaporizer is misfilled with desflurane. The calculated desflurane output of a misfilled enflurane vaporizer at a dial setting of 1% and a temperature of 22° C is 57.8%, or 9.6 MAC. For misfilled enflurane, isoflurane, and halothane vaporizers at dial settings equivalent to one MAC at 22° C, the calculated desflurane output is 14.0, 10.2, and 7.8 MAC, respectively. We conclude that the safe delivery of desflurane will require engineering safeguards, additional monitoring, and education of the anesthesia community.     

The Development and Teaching of the Ethical Principles and Guidelines for Family Scientists*

This article describes the development of the Ethical Principles and Guidelines for Family Scientists that the National Council on Family Relations Board of Directors unanimously approved. Furthermore, it discusses the importance of ethics education for family professionals and provides suggestions for educators. Finally, the ethical principles and guidelines are delineated. We argue that the development of a scholarship on ethics education is important for current and future family scientists.     

The intravascular contribution to fmri signal change: monte carlo modeling and diffusion-weighted studies in vivo

Understanding the relationship between fMRI signal changes and activated cortex is paramount to successful mapping of neuronal activity. To this end, the relative extravascular and intravascular contribution to fMRI signal change from capillaries (localized), venules (less localized) and macrovessels (remote, draining veins) must be determined. In this work, the authors assessed both the extravascular and intravascular contribution to blood oxygenation level-dependent gradient echo signal change at 1.5 T by using a Monte Carlo model for susceptibility-based contrast in conjunction with a physiological model for neuronal activation-induced changes in oxygenation and vascular volume fraction. The authors compared our Model results with experimental fMRI signal changes with and without velocity sensitization via bipolar gradients to null the intravascular signal. The model and experimental results are in agreement and suggest that the intravascular spins account for the majority of fMRI signal change on T₂^*-weighted images at 1.5 T.     

Myocardial perfusion and function in dogs with moderate coronary stenosis

MRI studies of first-pass contrast enhancement with polylysine-Gd-DTPA and myocardial tagging using spatial modulation of magnetization (SPAMM) were performed to assess the feasibility of a combined regional myocardial blood flow and 2D deformation exam. Instrumented closed-chest dogs were imaged at a baseline control state (Cntl) followed by two interventions: moderate coronary stenosis (St) achieved by partial occlusion of the left anterior descending (LAD) and moderate coronary stenosis with dobutamine loading (StD). Hypoperfusion of the anterior region (ANT) of the myocardium (LAD distribution) relative to the posterior wall (POS) based on the upslope of the signal intensity time curve from the contrast-enhanced MR images was demonstrated only with dobutamine loading (ANT:POS Cntl=1.077 ± 0.15 versus ANT:POS StD=0.477 ± 0.11, P<0.03) and was confirmed with radio-labeled microspheres measurements (ANT:POS Cntl=1.18 ± 0.2 ml/min/g versus ANT:POS StD=0.44 ± 0.1 ml/min/g; P<0.002). Significant changes in regional myocardial shortening were only seen in the StD state (P<0.02); the anterior region showed impaired myocardial shortening with dobutamine loading (P=NS), whereas the nonaffected POS region showed a marked increase in shortening when compared with Cntl (Cntl=0.964 ± 0.02 versus StD=0.884 ± 0.03; P<0.001). These results demonstrate that an integrated quantitative assessment of regional myocardial function and semiquantitative assessment of myocardial blood flow can be performed noninvasively with ultrafast MRI.     

Effect of Alendronate on Risk of Fracture in Women With Low Bone Density but Without Vertebral Fractures: Results From the Fracture Intervention Trial

Context.— Alendronate sodium reduces fracture risk in postmenopausal women who have vertebral fractures, but its effects on fracture risk have not been studied for women without vertebral fractures. Objective.— To test the hypothesis that 4 years of alendronate would decrease the risk of clinical and vertebral fractures in women who have low bone mineral density (BMD) but no vertebral fractures. Design.— Randomized, blinded, placebo-controlled trial. Setting.— Eleven community-based clinical research centers. Subjects.— Women aged 54 to 81 years with a femoral neck BMD of 0.68 g/cm² or less (Hologic Inc, Waltham, Mass) but no vertebral fracture; 4432 were randomized to alendronate or placebo and 4272 (96%) completed outcome measurements at the final visit (an average of 4.2 years later). Intervention.— All participants reporting calcium intakes of 1000 mg/d or less received a supplement containing 500 mg of calcium and 250 IU of cholecalciferol. Subjects were randomly assigned to either placebo or 5 mg/d of alendronate sodium for 2 years followed by 10 mg/d for the remainder of the trial. Main Outcome Measures.— Clinical fractures confirmed by x-ray reports, new vertebral deformities detected by morphometric measurements on radiographs, and BMD measured by dual x-ray absorptiometry. Results.— Alendronate increased BMD at all sites studied (P<.001) and reduced clinical fractures from 312 in the placebo group to 272 in the intervention group, but not significantly so (14% reduction; relative hazard [RH], 0.86; 95% confidence interval [CI], 0.73-1.01). Alendronate reduced clinical fractures by 36% in women with baseline osteoporosis at the femoral neck (>2.5 SDs below the normal young adult mean; RH, 0.64; 95% CI, 0.50-0.82; treatment-control difference, 6.5%; number needed to treat [NNT], 15), but there was no significant reduction among those with higher BMD (RH, 1.08; 95% CI, 0.87-1.35). Alendronate decreased the risk of radiographic vertebral fractures by 44% overall (relative risk, 0.56; 95% CI, 0.39-0.80; treatment-control difference, 1.7%; NNT, 60). Alendronate did not increase the risk of gastrointestinal or other adverse effects. Conclusions.— In women with low BMD but without vertebral fractures, 4 years of alendronate safely increased BMD and decreased the risk of first vertebral deformity. Alendronate significantly reduced the risk of clinical fractures among women with osteoporosis but not among women with higher BMD.      

Triazolam-induced changes in alcoholic thought processes

 This study was designed to examine and contrast cognitive effects (explicit memory and access to semantic knowledge) of the benzodiazepine Halcion (triazolam) in ten normal volunteers and ten cognitively unimpaired detoxified alcoholics. The two groups were indistinguishable from one another under placebo conditions on all measures of cognitive functioning. Under Halcion test conditions (0.375 mg PO), both groups were about equally impaired in their recall of to-be-remembered information. However, alcoholics, were more likely to recall information that they were not asked to remember (intrusion errors) on all measures of explicit remembering. Alcoholics also generated relatively uncommon (low frequency) responses from semantic memory, rather than common, categorically related associations in response to stimuli such as types of vegetables, flowers, and fruit following the administration of Halcion, but were not different from normal volunteers in the types of responses generated under placebo conditions. These findings suggest that a drug challenge that simulates many of the effects of acute alcohol administration induces alcoholics to think and remember differently (qualitatively) from normal volunteers. Received: 7 July 1997 / Final version: 22 September 1997     

Cost-effectiveness analysis: What is it and how it influence neurology

Cost-effectiveness analysis (CEX) refers to a set of research methods that consider the resources consumed by a medical technology in decisions about how best to use the technology. This analytic method is an evolving, controversial, and often misunderstood field in health services research. The basic set of principles underlying CEA is deceptively simple, but sufficient methodological challenges and controversies exist that have, thus far, limited its use in the development of health policy and in bedside decision making. Nonetheless, neurologists like other specialty groups may feel concerned that the results from such analyses may prove unfavorable to their specialty and the patients they serve. This article reviews the fundamental notions surrounding CEA, provides examples from the literature with particular relevance to the neurological community, and highlights critical issues for neurologists regarding the future of CEA.