The treatment of traumatic shock: recent advances and unresolved questions

Uncontrolled bleeding remains a leading cause of potentially preventable death after trauma. Timely, adequate resuscitation in traumatic shock is an essential, lifesaving aspect of polytrauma care. Whilst basic principles in the treatment of traumatic shock remain the same-achieving hemorrhage control and replacing lost volume, the way this is achieved has changed significantly in the last five years. The abandonment of blood pressure driven uncontrolled fluid resuscitation, the introduction of the concept of hemostatic resuscitation, and the increasing use of massive transfusion protocols have all contributed to an improvement in timely access to various blood products. The increase in knowledge regarding the pathophysiology of trauma, the availability of adjuncts, and the array of resuscitation monitoring options available have all contributed to a potentially improved approach to resuscitation. The purpose of this report is to review the most important advances in traumatic shock therapy in the last five years.

Clarifying the concepts of confidence and competence to produce appropriate self-evaluation measurement scales

INTRODUCTION

This paper reviews the literature on self-evaluation and discusses the findings of a small-scale qualitative study which explored the terms 'confidence' and 'competence' as useful measures in a self-evaluation scale. Four pre-registration house officers took part in interviews and completed a provisional instrument to assess their perceived competence.

FINDINGS

Competence and confidence are useful terms for house officers expressing beliefs about their ability to perform their job but the terms should not be used synonymously. In our study, 'competent' represented what individuals knew about their ability and was based on the individual's previous experience of the task. 'Confident' described a judgement which influenced whether an individual was willing or not to undertake an activity. Confidence was not necessarily based on known levels of competence and therefore performance of tasks which were unfamiliar to the house officer also involved the assessment of risk. The authors give examples of task and skill scales which may be useful in the process of self-evaluation by pre-registration house officers.

CONCLUSIONS

The authors suggest that the process of assessing oneself is complicated, and by its very nature can never be objective or free from the beliefs and values individuals hold about themselves. Therefore self-evaluation instruments are best used to help individuals analyse their work practices and to promote reflection on performance. They should not be used to judge the 'accuracy' of the individual's evaluation.

Identifying appropriate tasks for the preregistration year: modified Delphi technique

OBJECTIVES

To identify the tasks that should constitute the work of preregistration house officers to provide the basis for the development of a self evaluation instrument.

DESIGN

Literature review and modified Delphi technique.

SETTING

Northern Deanery within the Northern and Yorkshire office NHS executive.

SUBJECTS

67 educational supervisors of preregistration house officers.

MAIN OUTCOME MEASURES

Percentage of agreement by educational supervisors to tasks identified from the literature.

RESULTS

Over 61% of communication items, 70% of on call patient care items, 75% of routine patient care items, 45% of practical procedure items, and over 63% of self management items achieved over 95% agreement that they should be part of the house job of preregistration house officers. Poor agreement was found for the laboratory and clinical investigations that house officers could perform with or without supervision.

CONCLUSIONS

The tasks of house officers were identified but issues in using this method and in devising a universally acceptable list of tasks for preregistration house officers were apparent.

Comparative Validity of the MMPI-2 Wiener-Harmon Subtle-Obvious Scales in Male Prison Inmates

The Wiener-Harmon subtle-obvious MMPI subscales (Wiener, 1948; Wiener & Harmon, 1946) have been the subject of considerable debate. In this study, we examined the intercorrelations among full clinical scale T scores and their subtle and obvious subscales in an offender population. Low subtle to full-scale correlations were observed, suggesting that these items contribute little to full-scale scores. Further, we explored the criterion validity of the MMPI-2 subtle-obvious scales in this forensic sample. The results demonstrated that the obvious scales of the MMPI-2 had greater criterion validity than the subtle scales when compared to crime history data. Scores on the subtle subscales were unrelated to crime history. The Ma-O subscale demonstrated the strongest association to crime history data. The findings from this study add to a mounting body of evidence indicating that when respondents are in a position to understand item content, and can therefore provide a direct self-appraisal, responses are most predictive of clinical criteria.

Four years' experience of a senior house officer rotation in general medicine including general practice

A four-month post in general practice was included as an option available to doctors applying for a year-long medical senior house officer (SHO) rotation since August 1993. This study sought the views of SHOs before and after undertaking the general practice post. SHOs gained an understanding of modern general practice and changed their views about certain aspects of general practice. They reported gaining a range of generic skills, which included communication, consultation, and clinical skills. These perceived benefits suggest that such experience merits wider adoption and further evaluation.

Validation of the proximal flow convergence method. Calculation of orifice area in patients with mitral stenosis

BACKGROUND

It has been proposed recently that measuring the flow convergence region proximal to an orifice by Doppler flow mapping can provide a means of calculating regurgitant flow rate. Although verified in experimental models, this approach is difficult to validate clinically because there is no ideal gold standard for regurgitant flows in patients. However, this method also can be used to derive cardiac output or flow rate proximal to stenotic orifices and therefore to calculate their areas by the continuity equation (area = flow rate/velocity). Applying this method in mitral stenosis would provide a unique way of validating the underlying concept because the predicted areas could be compared with those measured directly by planimetry.

METHODS AND RESULTS

We studied 40 patients with mitral stenosis using imaging and Doppler echocardiography. Doppler color flow recordings of mitral inflow were obtained from the apex, and the radius of the proximal flow convergence region was measured at its peak diastolic value from the orifice to the first color alias along the axis of flow. Flow rate was calculated assuming uniform radial flow convergence toward the orifice, modified by a factor that accounted for the inflow funnel angle formed by the mitral leaflets. Mitral valve area was then calculated as peak flow rate divided by peak velocity by continuous-wave Doppler. The calculated areas agreed well with those from three comparative techniques over a range of 0.5 to 2.2 cm2: 1) cross-sectional area by planimetry (y = 1.08x-0.13, r = .91, SEE = 0.21 cm2); 2) area derived from the Doppler pressure half-time (y = 1.02x-0.14, r = .89, SEE = 0.24 cm2); and 3) area calculated by the Gorlin equation in the 26 patients who underwent catheterization (y = 0.89x + 0.08, r = .86, SEE = 0.24 cm2). Agreement with planimetry was similar for 22 patients with mitral regurgitation and 18 without it (P > .6), as well as for 6 in atrial fibrillation (P > .2).

CONCLUSIONS

These results validate the proximal flow convergence concept in the clinical setting and also demonstrate that it can be extended to orifice area calculation using the continuity equation.

The value and promise of echocardiography in acute myocardial infarction and coronary artery disease

Two-dimensional and Doppler echocardiography have become extremely useful in the management of patients with acute myocardial infarction (AMI). Echocardiography is noninvasive, relatively inexpensive, and has no known biohazards. It offers unequaled information about cardiac anatomy and function. In the acute setting it is useful in the diagnosis of AMI and its complications. It is an excellent tool for monitoring therapy. Echocardiography has been shown to be useful in risk stratification upon presentation to the emergency ward and prior to hospital discharge. Stress echocardiography has broadened and sharpened the diagnostic and prognostic information. Contrast echocardiography has promise for demonstrating coronary artery flow. Research in ultrasonic myocardial tissue characterization shows potential for differentiating ischemic myocardium from infarcted myocardium. Thus, echocardiography is likely to become increasingly important in the future management of patients with AMI.

Papillary muscle traction in mitral valve prolapse: quantitation by two-dimensional echocardiography

Previous angiographic observations in patients with mitral valve prolapse have suggested that superior leaflet displacement results in abnormal superior tension on the papillary muscle tips that causes their superior traction or displacement. It has further been postulated that such tension can potentially affect the mechanical and electrophysiologic function of the left ventricle. The purpose of this study was to confirm and quantitate this phenomenon noninvasively by using two-dimensional echocardiography to determine whether superior displacement of the papillary muscle tips occurs and its relation to the degree of mitral leaflet displacement. Directed echocardiographic examination of the papillary muscles and mitral anulus was carried out in a series of patients with classic mitral valve prolapse and results were compared with those in a group of normal control subjects. Distance from the anulus to the papillary muscle tip was measured both in early and at peak ventricular systole. In normal subjects, this distance did not change significantly through systole, whereas in the patient group it decreased, corresponding to a superior displacement of the papillary muscle tips toward the anulus in systole (8.5 +/- 2.6 vs. 0.8 +/- 0.7 mm; p less than 0.0001). This superior papillary muscle motion paralleled the superior displacement of the leaflets in individual patients (y = 1.0x + 0.8; r = 0.93) and followed a similar time course.(ABSTRACT TRUNCATED AT 250 WORDS)

Verhulstian analysis of the growth of transplantable mammary tumours in sialoadenectomized mice

In this report we have analysed data published in 1989 by Inui et al. (Incidence of precancerous foci of mammary glands and growth rate of transplantable mammary cancers in sialoadenectomized mice. J. Natl Cancer Inst. 81, 1660) involving the effects of perturbation of the epidermal growth factor (EGF) status of mammary tumour-bearing mice on subsequent volumetric responses. Removal of an endogenous EGF stimulus by surgical ablation of the submaxillary glands, the major EGF-producing organ in mice, produced significantly slower growth of rodent mammary neoplasms, decreased success rate of transplantation, and an increase in the latent period before growth occurred. Administration of i.p. EGF (5 micrograms/mouse/day) to sialadectomized tumour-bearing mice would however, increase tumour growth rate. Data were analysed using the Verhulst equation which indicated that the observed effects on tumour volumetrics by either sialoadenectomy or EGF administration could be interpreted as being produced through paracrine pathways. The use of the Verhulstian analysis indicates that it is possible to analyse neoplastic responses and infer whether paracrine or autocrine pathways are involved.

Modification of the growth rates and hypoxic fractions of xenografted A431 tumors by sialoadenectomy or exogenously supplied epidermal growth factor

We studied A431 epidermoid carcinomas xenografted into male nude mice either in the unperturbed state or after either surgical removal of the salivary glands or i.p. injection of exogenous epidermal growth factor (0.2 mg/kg daily for 7 days). The percentage of hypoxic cells in unperturbed tumors was 10.5% (95% confidence limits, 6.6-16.8%). In mice that received epidermal growth factor injections, hypoxic percentages decreased to 3.7% (1.7-7.8%), and tumor growth rates increased. In sialoadenectomized mice, hypoxic percentages increased to 35.2% (27.1-45.6%), and tumor growth rates decreased. These data indicate that the biology of solid tumors can be significantly modified by the host status.

Impact of impinging wall jet on color Doppler quantification of mitral regurgitation

BACKGROUND

In clinical color Doppler examinations, mitral regurgitant jets are often observed to impinge on the left atrial wall immediately beyond the mitral valve. In accordance with fluid dynamics theory, we hypothesized that a jet impinging on a wall would lose momentum more rapidly, undergo spatial distortion, and thus have a different observed jet area from that of a free jet with an identical flow rate.

METHODS AND RESULTS

To test this hypothesis in vivo, we studied 44 patients with mitral regurgitation--30 with centrally directed free jets and 14 with eccentrically directed impinging wall jets. Maximal color jet areas (cm2) (with and without correction for left atrial size) were correlated with mitral regurgitant volumes, flow rates, and fractions derived from pulsed Doppler mitral and aortic forward flows. The groups were compared by analysis of covariance. Mean +/- SD mitral regurgitant fraction, regurgitant volume, and mean flow rate averaged 37 +/- 17%, 3.06 +/- 2.65 l/min, and 147 +/- 118 ml/sec, respectively. The maximal jet area from color Doppler imaging correlated relatively well with the mitral regurgitant fraction in the patients with free mitral regurgitant jets (r = 0.74, p less than 0.0001) but poorly in the patients with impinging wall jets (r = 0.42, p = NS). Although the mitral regurgitant fraction was larger (p less than 0.05) in patients with wall jets (44 +/- 20%) than in those with free jets (33 +/- 15%), the maximal jet area was significantly smaller (4.78 +/- 2.87 cm2 for wall jets versus 9.17 +/- 6.45 cm2 for free jets, p less than 0.01). For the same regurgitant fraction, wall jets were only approximately 40% of the size of a corresponding free jet, a difference confirmed by analysis of covariance (p less than 0.0001).

CONCLUSIONS

Patients with mitral regurgitation frequently have jets that impinge on the left atrial wall close to the mitral valve. Such impinging wall jets are less predictable and usually have much smaller color Doppler areas in conventional echocardiographic views than do free jets of similar regurgitant severity. Jet morphology should be considered in the semiquantitative interpretation of mitral regurgitation by Doppler color flow mapping. Future studies of the three-dimensional morphology of wall jets may aid in their assessment.

Atrial enlargement as a consequence of atrial fibrillation. A prospective echocardiographic study

To test the hypothesis that atrial enlargement can develop as a consequence of atrial fibrillation, left and right atrial dimensions were measured echocardiographically at two different time points in patients with atrial fibrillation. Patients were selected who initially had normal atrial sizes and who had no evidence of significant structural or functional cardiac abnormalities other than atrial fibrillation either by history or two-dimensional and Doppler echocardiography. Fifteen patients were studied (12 men and three women; mean age, 67.3 years). Average time between studies was 20.6 months. Three orthogonal left atrial dimensions and two right atrial dimensions were measured, and all were found to increase significantly between studies. Also, highly significant increases in calculated left atrial volume (from 45.2 to 64.1 cm3, p less than 0.001) and right atrial volume (from 49.2 to 66.2 cm3, p less than 0.001) were observed. The relative extents of left and right atrial volume increase did not differ, and left ventricular size did not change significantly between studies. These results indicate that atrial enlargement can occur as a consequence of atrial fibrillation. The maintenance of sinus rhythm, therefore, may prevent atrial enlargement and its adverse clinical effects.

[Echocardiographic detection of right atrial extension of hepatocellular carcinoma]

Right atrial extension of hepatocellular carcinoma is extremely rare and echocardiographic features of such extension have been described only in four patients. In this report, we present two patients with right atrial extension of hepatocellular carcinoma that was detected by echocardiography.

Three-dimensional echocardiographic reconstruction of the mitral valve, with implications for the diagnosis of mitral valve prolapse

Mitral valve prolapse has been diagnosed by two-dimensional echocardiographic criteria with surprising frequency in the general population, even when preselected normal subjects are examined. In most of these individuals, however, prolapse appears in the apical four-chamber view and is absent in roughly orthogonal long-axis views. Previous studies of in vitro models with nonplanar rings have shown that systolic mitral annular nonplanarity can potentially produce this discrepancy. However, to prove directly that apparent leaflet displacement in a two-dimensional view does not constitute true displacement above the three-dimensional annulus requires reconstruction of the entire mitral valve, including leaflets and annulus. Such reconstruction would also be necessary to explore the complex geometry of the valve and to derive volumetric measures of superior leaflet displacement. A technique was therefore developed and validated in vitro for three-dimensional reconstruction of the entire mitral valve. In this technique, simultaneous real-time acquisition of images and their spatial locations permits reconstruction of a localized structure by minimizing the effects of patient motion and respiration. By applying this method to 15 normal subjects, a coherent mitral valve surface could be reconstructed from intersecting scans. The results confirm mitral annular nonplanarity in systole, with a maximum deviation of 1.4 +/- 0.3 cm from planarity. They directly show that leaflets can appear to ascend above the mitral annulus in the apical four-chamber view, as they did in at least one view in all subjects, without actual leaflet displacement above the entire mitral valve in three dimensions, thereby challenging the diagnosis of prolapse by isolated four-chamber view displacement in otherwise normal individuals. This technique allows us to address a uniquely three-dimensional problem with high resolution and provide new information previously unavailable from the two-dimensional images. This new appreciation should enhance our ability to ask appropriate clinical questions relating mitral valve shape and leaflet displacement to clinical and pathologic consequences.

[Echocardiographic diagnosis of angiosarcoma of the heart]

Cardiac angiosarcoma is the most common primary malignant tumour of the heart that is rarely diagnosed ante mortem. The authors present the case of a 73-year-old female with right atrial angiosarcoma that was followed-up echocardiographically for 20 months. Echocardiographic features suggestive of primary and metastatic malignant tumours of the right heart are discussed.

Reconsideration of echocardiographic standards for mitral valve prolapse: lack of association between leaflet displacement isolated to the apical four chamber view and independent echocardiographic evidence of abnormality

Mitral valve prolapse by current echocardiographic criteria can be diagnosed with surprising frequency in the general population, even when preselected normal subjects are examined. In most of these individuals, however, prolapse is present in the apical four chamber view and absent in roughly perpendicular long-axis views. Previous studies have shown that systolic annular nonplanarity can cause apparent prolapse in the four chamber view without actual leaflet displacement above the most superior points of the anulus, and there is evidence for such nonplanarity in vivo. It is then reasonable to ask whether superior leaflet displacement limited to the four chamber view has any pathologic significance or complications. The purpose of this study, therefore, was to address the following hypothesis: that patients with superior leaflet displacement confined to the four chamber view have no higher frequency of associated echocardiographic abnormalities than do patients without displacement in any view. Such abnormalities, which would provide independent evidence of mitral valve pathology or dysfunction, include leaflet thickening, left atrial enlargement and mitral regurgitation. Leaflet displacement was measured in the parasternal long-axis and apical four chamber views in 312 patients who were studied retrospectively and selected for the absence of forms of heart disease other than mitral valve prolapse. Leaflet thickness and left atrial size were measured and mitral regurgitation was graded. Patients with leaflet displacement limited to the four chamber view were no more likely to have associated abnormalities than were patients without displacement in any view (0 to 2% prevalence, p greater than 0.5). In contrast, patients with leaflet displacement in the long-axis view were significantly more likely to have associated abnormalities (12 to 24%, p less than 0.005), the frequency of which increased with the extent of leaflet displacement in that view (p less than 0.0001). These results suggest that displacement limited to the apical four chamber view is, in general, a normal geometric finding unassociated with echocardiographic evidence of pathologic significance.

The relationship of mitral annular shape to the diagnosis of mitral valve prolapse

The geometric or anatomic diagnosis of mitral valve prolapse, as opposed to the pathologic diagnosis of myxomatous valve disease, is based on the relationship of the mitral leaflets to the surrounding anulus. Current echocardiographic criteria for this diagnosis include leaflet displacement above the annular hinge points in any two-dimensional view; implicit in this equivalent use of intersecting views is the assumption that the mitral anulus is a euclidean plane. Prolapse by these criteria is found in a surprisingly large proportion of the general population. In most of these individuals, however, prolapse is present in the apical four-chamber view and absent in roughly orthogonal long-axis views of the left ventricle. This frequently observed discrepancy between leaflet-annular relationships in intersecting views suggests an underlying geometric property of the mitral apparatus that would produce the appearance of prolapse in one view without actual leaflet distortion. To address this possibility, a model of the mitral valve and anulus was constructed. When the model anulus was given a nonplanar, saddle-shaped configuration, the clinical observations were reproduced: the leaflets appeared to lie above the low points of the anulus in one plane, and below its high points in a perpendicular plane. Therefore, the appearance of mitral valve prolapse can occur without actual leaflet displacement above the most superior points of the mitral anulus if the anulus is nonplanar. To determine whether this pattern is reflected in the human mitral anulus, two-dimensional echocardiographic views of the mitral apparatus were obtained by rotation about the cardiac apex in 20 patients without evident annular or rheumatic valvular disease. In all cases the mitral anulus, as reconstructed from these views, had a nonplanar systolic configuration, with high points located anteriorly and posteriorly. This is consistent with the findings of other groups in animals, and would favor the appearance of prolapse in the four-chamber view and its absence in long-axis views that are oriented anteroposteriorly. This model can therefore explain the frequently observed discrepancy between leaflet-annular relationships in roughly orthogonal views. It challenges the assumption that the mitral anulus is planar as well as the diagnosis of prolapse in many otherwise normal individuals based on that assumption.

Fourth ventricular tanycytes: a possible relationship with monoaminergic nuclei

Tanycytes were found in discrete areas on the floor of the fourth ventricle of the developing and adult rabbit. The apical surfaces of the somas extended into the fourth ventricle and the shafts extended into the substance of the rhombencephalon. Shafts from midline tanycytes on the floor of the caudal fourth ventricle entered nuclei raphe obscurus and pallidus and shafts from midline tanycytes on the floor of the rostral fourth ventricle entered nuclei raphe dorsalis and centralis superior. These four raphe nuclei all contained serotonergic neurons and formed dendrite bundles in association with the tanycyte shafts. Shafts of tanycytes on the medial floor of the fourth ventricle entered nucleus intercalatus, and shafts of tanycytes on the lateral floor of the fourth ventricle entered locus coeruleus. Both of these nuclei contained noradrenergic cell bodies. The tanycyte shafts terminated only in these monoaminergic nuclei and did not extend to the pial surface of the ventral brain stem. We suggest that these tanycytes constitute a possible transport system for substances between the cerebrospinal fluid of the fourth ventricle and monoaminergic nuclei of the brain stem, in a role similar to that proposed for tanycytes of the median eminence.

Dendrite bundles in nuclei raphe dorsalis and centralis superior of the rabbit: a possible substrate for local control of serotonergic neurons

A Golgi-Cox, cresyl violet, and histofluorescence study has revealed the presence of dendrite bundles in nuclei raphe dorsalis (NRD) and centralis superior (NCS) in the rabbit brain stem. In NRD, bundles were found in the midline, traversing the medial longitudinal fasciculus (MLF) and in a circumferential location around the MLF. In NCS, bundles were found oriented vertically in the midline. Serotonergic dendrites predominated in these bundles, but non-serotonergic dendrites from cells of the dorsal tegmental nucleus, adjacent reticular formation, and NCS also were present. Long descending shafts from tanycytes on the floor of the rostral fourth ventricle were also found in the dendrite bundles of both NRD and NCS. We suggest that the dendrite bundles constitute a local neuronal system for regulating the activity of these raphe neurons.