Cerebrovascular Autoregulation Monitoring in the Management of Adult Severe Traumatic Brain Injury: A Delphi Consensus of Clinicians.

BACKGROUND: Several methods have been proposed to measure cerebrovascular autoregulation (CA) in traumatic brain injury (TBI), but the lack of a gold standard and the absence of prospective clinical data on risks, impact on care and outcomes of implementation of CA-guided management lead to uncertainty. AIM: To formulate statements using a Delphi consensus approach employing a group of expert clinicians, that reflect current knowledge of CA, aspects that can be implemented in TBI management and CA research priorities. METHODS: A group of 25 international academic experts with clinical expertise in the management of adult severe TBI patients participated in this consensus process. Seventy-seven statements and multiple-choice questions were submitted to the group in two online surveys, followed by a face-to-face meeting and a third online survey. Participants received feedback on average scores and the rationale for resubmission or rephrasing of statements. Consensus on a statement was defined as agreement of more than 75% of participants. RESULTS: Consensus amongst participants was achieved on the importance of CA status in adult severe TBI pathophysiology, the dynamic non-binary nature of CA impairment, its association with outcome and the inadvisability of employing universal and absolute cerebral perfusion pressure targets. Consensus could not be reached on the accuracy, reliability and validation of any current CA assessment method. There was also no consensus on how to implement CA information in clinical management protocols, reflecting insufficient clinical evidence. CONCLUSION: The Delphi process resulted in 25 consensus statements addressing the pathophysiology of impaired CA, and its impact on cerebral perfusion pressure targets and outcome. A research agenda was proposed emphasizing the need for better validated CA assessment methods as well as the focused investigation of the application of CA-guided management in clinical care using prospective safety, feasibility and efficacy studies.

Autoregulation assessment by direct visualisation of pial arterial blood flow in the piglet brain.

Impairment of cerebrovascular autoregulation (CAR) is common after brain injury, although the pathophysiology remains elusive. The mechanisms of vascular dysregulation, their impact on brain function, and potential therapeutic implications are still incompletely understood. Clinical assessment of CAR remains challenging. Observational studies suggest that CAR impairment is associated with worse outcomes, and that optimization of cerebral blood flow (CBF) by individual arterial blood pressure (ABP) targets could potentially improve outcome. We present a porcine closed cranial window model that measures the hemodynamic response of pial arterioles, the main site of CBF control, based on changes in their diameter and red blood cell velocity. This quantitative direct CAR assessment is compared to laser Doppler flow (LDF). CAR breakpoints are determined by segmented regression analysis and validated using LDF and brain tissue oxygen pressure. Using a standardized cortical impact, CAR impairment in traumatic brain injury can be studied using our method of combining pial arteriolar diameter and RBC velocity to quantify RBC flux in a large animal model. The model has numerous potential applications to investigate CAR physiology and pathophysiology of CAR impairment after brain injury, the impact of therapeutic interventions, drugs, and other confounders, or to develop personalized ABP management strategies.

A case study in contesting the conventional wisdom: school-based fluoride mouthrinse programs in the USA.

This paper presents the events surrounding the dissemination of the results of a major preventive dentistry demonstration program designed and conducted to provide evidence of the effectiveness and actual costs of a combination of commonly used preventive procedures. It then reviews the controversy provoked when the results of that program were counter to the conventional wisdom of the day, prevailing national policy, and public health practice. An analysis of possible reasons for this reaction follows. The paper concludes with some observations about how such a situation might be approached to minimize similar controversy in the future.

Tolerance to morphine analgesia from brief exposure to a palatable solution.

The onset of tolerance to morphine analgesia was studied in 34 female Wistar rats immediately after they drank a dextrose-saccharin cocktail or tap water for 6 or 24 hours. Tail flick tests conducted at the end of the drinking period showed no analgesia in cocktail or water groups. Morphine (3.5 mg/kg) was then injected subcutaneously, and after 20 min another series of tail flick tests was conducted. Morphine produced strong analgesia in rats that drank water, but only partial analgesia in rats that drank the cocktail. This reduction in morphine analgesia did not differ in comparisons between 6-hour and 24-hour cocktail groups. The results were interpreted as indicating that ingestion of the cocktail produced tolerance for morphine in the test of analgesia, and that such factors as novelty of flavor stimulation or stress from repeated testing were unlikely to yield the attenuation of analgesia that was observed. It was concluded that processes that produce tolerance become active in less than 6 hours.

The cost and effectiveness of school-based preventive dental care.

The National Preventive Dentistry Demonstration Program assessed the cost and effectiveness of various types and combinations of school-based preventive dental care procedures. The program involved 20,052 first, second, and fifth graders from five fluoridated and five nonfluoridated communities. These children were examined at baseline and assigned to one of six treatment regimens. Four years later, 9,566 members of this group were examined again. Analyses of their dental examination data showed that dental health lessons, brushing and flossing, fluoride tablets and mouthrinsing, and professionally applied topical fluorides were not effective in reducing a substantial amount of dental decay, even when all of these procedures were used together. Occlusal sealants prevented one to two carious surfaces in four years. Children who were especially susceptible to decay did not benefit appreciably more from any of the preventive measures than did children in general. Annual direct per capita costs were $23 for sealant or fluoride prophy/gel applications and $3.29 for fluoride mouthrinsing. Communal water fluoridation was reaffirmed as the most cost-effective means of reducing tooth decay in children.

Operation of the National Preventive Dentistry Demonstration Program.

Operation of large-scale, multiple-site demonstration programs is an infrequent activity, one for which most investigators have had little previous experience. The success of a demonstration program, however, often rests on operational aspects. Following the completion of a major demonstration, the writers discuss the design of their program, the problems they encountered in its operation, and the aspects they would change in future demonstrations.

Indications for sealant use in a community-based preventive dentistry program.

Dental caries is a disease that recently has undergone, and may still be undergoing, dramatic changes in distribution of incidence and prevalence. The most recent epidemiologic data available have been reviewed in this paper to illustrate that caries is becoming a disease primarily of pits and fissures, with less differentiation than previously acknowledged between fluoridated and fluoride-deficient areas. The present distribution of caries suggests that prevention may be accomplished more effectively through targeted sealant programs than through currently popular mass preventive programs. Existing information can be used to identify logical target groups for sealant programs, and age specific tooth eruption and caries attack information can be used to design delivery methods. Although the adoption of targeted sealant programs represents a departure from the traditional mass approach to prevention in dental programs, the present-day caries distribution requires that the initiation of such programs be given serious consideration. At the very least program administrators are encouraged to invoke the planning-implementation-evaluation process. Current programs should be evaluated carefully in view of today's disease patterns and the clinical significance of the results achieved. The content, design, and timing of future community-based programs should reflect individualized community diagnosis and the application of new epidemiologic data as well as a careful evaluation of the results achieved by current preventive procedures.

Two-dimensional echocardiographic detection and diagnostic features of tricuspid papillary fibroelastoma.

Cardiac papillary fibroelastomas are rare and benign primary tumors in the cardiac valves or occasionally the mural endocardium. Before 1977, these tumors were diagnosed exclusively at postmortem examination. Over the last few years, a handful of cases have been diagnosed in vivo by echocardiography. In this report, we describe the first tricuspid valve papillary fibroelastoma detected by echocardiography in an adult. Clinical and echocardiographic features are discussed.

Reactive hypoglycemia and A-cell ('pancreatic') glucagon deficiency in the adult.

Serum glucose, A-cell (IRGA) and total glucagon (IRGT), insulin, growth hormone, cortisol, triiodothyronine, and thyroxine values were measured in the fasting state and in response to oral glucose, intravenously administered arginine, and a meal of pan-broiled ground beef in 31 symptomatic patients and 11 normal subjects. Twenty-four patients and 11 control subjects had normal glucose tolerance (group 1); seven patients had reactive hypoglycemia (group 2). Under all conditions, serum IRGA value was significantly lower in group 2 than in group 1. Glucose, arginine, or meat increased serum IRGT levels. This response did not differ significantly in the two groups, nor did the secretion of the other measured hormones. We conclude that A-cell insufficiency can contribute to reactive hypoglycemia in the adult.

The hemispheric specialization for linguistic and non-linguistic tactile stimuli in third grade children.

Thirty third-grade children were given two dichaptically presented tests of hemispheric specialization. Specialization for linguistic stimuli was measured by a letters task and specialization for spatial stimulus was measured by a nonsense shapes task. The results showed a significant right hemisphere processing advantage for tactually presented spatial stimuli. There was no significant processing advantage for either hemisphere with tactually presented linguistic stimuli. The right hemisphere specialization for tactually presented spatial stimuli was present for both boys and girls. Thus there was no evidence of sexual bimorphism in the neurological organization of third grade children for spatial processing.

The Multidimensional Scaling Of A Set Of Artistic Drawings : Perceived Structure And Scale Correlates.

Product-centered research on creativity approaches the criterion problem of what is to be the referent for creativity through the analysis of tangible products such as a r t objects, writing, or scientific achievements. The present research is concerned with the evaluation and study of artist drawings contributed by sophomore students a t the Rhode Island School of Design. Multi-dimensional scaling methods were applied to similarity judgments obtained from art experts on two separate sets of 26 drawings. Three similarity dimensions accounted for the interstimulus distances for each set of drawings. Although no statistical test was available, the dimensions from the two seta appeared to correspond. Scale values of 4 drawings common to the two sets were consistent, and the dimensions appeared to define very similar stimulus characteristics. It was concluded that multidimensional scaling procedures provided a means for differentiating among a set of complex, esthetic products. Scale values of drawings on the three dimensions also correlated differentially with cognitive and achievement measures available on the students, suggesting that product dimensions identified via similarity judgments were related to characteristics of individuals producing the products. Hypotheses were developed as to the psychological meaning of the three product dimensions.