Search PubMed⌕ Search

Biomedical subjects

S Vig

Publications and source records attributed to S Vig.

At least 19 recordsLinked to original sources
PubMed2001

Contrast-enhanced magnetic resonance angiography of the iliac arteries: optimization by injection simulation.

Protocols for contrast-enhanced magnetic resonance angiography (CE-MRA) of the iliac arteries were optimized by computer simulations based on an impulse response function (IRF) of contrast agent (CA) concentration as a function of time obtained for 20 patients. Protocols with sequential, centric, and elliptical k-space coverage, different repetition rates (5 and 10 ms), and CA doses (0.1, 0.2, and 0.3 mmol/kg b.w.) were compared in terms of signal-to-noise ratio (SNR), distortion of vessel profiles, and sensitivity to timing errors. IRF-based simulations successfully characterized CA recirculation. Slow-rate CA infusions were found to achieve relatively high enhancement. In terms of SNR, there is no advantage in increasing the repetition rate. Distortion of vessel profiles is more likely in elliptic and centric k-space coverage. Protocols based on sequential k-space coverage and relatively long CA infusions proved to be particularly suited to large-FOV iliac examinations as they are relatively insensitive to timing errors.

Adult↗
PubMed2001

Thromboelastography: a reliable test?

The thromboelastograph (TEG), a measure of global haemostasis, is routinely used during cardiac and hepatic surgery to optimize blood product selection and usage. It has recently been suggested that it may also be a useful tool to screen patients with hypercoagulable states. Limited published data on performance characteristics has led to speculation regarding its consistency and, therefore, validity of the results. This study was designed to assess the effect of stability of blood samples prior to testing, repeated sampling, intra- and inter-assay variability using the native, celite, tissue factor (TF) and Reopro-modified TEG. Analysis of native and celite samples after storage over 90 min showed a period of instability up to 30 min. Thereafter, all parameters between 30 and 90 min were stable [P = not significant (NS)]. When the same sample was repeatedly assayed, both native and celite TEG parameters showed a significant change towards hypercoagulability (P < 0.01), whereas the TF and Reopro-modified TEG showed no change. Intra- and inter-assay variability on samples tested after 30 min showed excellent reproducibility for all parameters (P = NS). The data suggest that the TEG is a useful tool in haemostasis but requires a formal standard operating procedure to be adopted that takes into account the initial period of sample instability.

Blood Specimen Collection↗
PubMed2001

Lessons to be learned: a case study approach insulinoma presenting as a change in personality.

A 43-year-old man presented with attacks of altered behaviour over a short period of time; they were associated with episodes of hypoglycaemia. The clinical suspicion of insulinoma prompted investigations that quickly established serum insulin and C-peptide levels to be elevated at the times when blood glucose values were low. A physical lesion was found in the head of the pancreas by means of computerised tomography and endo-duodenal ultrasound scan; an octreotide scan was negative. The patient underwent laparotomy and enucleation of a benign tumour, measuring 2.6 cm in diameter, lying within the head of the pancreas; histological examination confirmed it to be an insulinoma. Postoperatively, the patient's personality gradually became more normal and his fasting blood glucose concentrations returned to within normal limits. The diagnosis and management of insulinoma are discussed in the context of this clinical case; there is also reference to the protean clinical manifestations that may occur in this condition- and its differential diagnosis.

Adult↗
PubMed2000

Herbal medicines: current trends in anesthesiology practice--a hospital survey.

STUDY OBJECTIVES: To develop a simple survey to determine the patient population actively utilizing dietary supplements and/or herbs, during the preoperative period. DESIGN: Prospective study, with survey instrument. SETTING: University medical center. PATIENTS: 1,017 patients presenting for preanesthetic evaluation prior to outpatient surgery. INTERVENTIONS: After undergoing preanesthetic evaluation, patients were asked to complete a survey listing which of the nine most popular nutraceuticals currently available on the market they were using. MEASUREMENTS AND MAIN RESULTS: A total of 1017 surveys were submitted over a period of five months, with 32% being poorly completed and thus discarded. Of the remaining 755 valid surveys, 482 patients used at least one nutraceutical agent. 90% of these patients were using vitamins, 43% garlic extracts, 32% Gingko Biloba, 30% St. John's Wort, 18% Ma Huang, 12% Ecchinaceae, 10% Aloe, 8% Cascare, 3% licorice. CONCLUSION: A significant population of patients scheduled for an elective surgical procedure are self-administering nutraceutical agents. Some of these agents have the potential to cause serious drug interactions and hemodynamic instability during surgery. Hence, it may be important to identify patients self-administering these medications, during the preoperative period.

Adolescent↗
PubMed1999

Autistic features in young children with significant cognitive impairment: autism or mental retardation?

This review addresses the issues and challenges related to the differential diagnosis of autism in preschool children with significant cognitive impairment. Issues affecting differential diagnosis include the use of traditional diagnostic guidelines for preschoolers with developmental delays, developmental changes in behavioral characteristics, the involvement of cognitive factors in symptom expression, and the overlap between autism and mental retardation in individuals with significant cognitive impairment. The usefulness of autistic features for differential diagnosis is explored in terms of the core deficits of autism.

Age Factors↗
PubMed1999

Intermittent claudication: a condition with underrated risks.

Intermittent claudication (IC) is a symptom of peripheral arterial occlusive disease (PAOD); it is subjective and therefore difficult to measure reliably. Both the WHO/Rose Questionnaire and the Edinburgh Questionnaire have been used widely, but they have a low sensitivity and therefore underestimate the true prevalence of IC. The addition of a clinical examination does not necessarily eliminate errors found on questionnaires alone. The single most important part of the physical examination to confirm a diagnosis of IC is the palpation of the patient's peripheral pulses, which alone appears to be more sensitive, but less specific, than the questionnaires. The most useful noninvasive test is the ankle-brachial pressure index (ABPI), and it has been suggested that a resting ABPI of 0.9 is up to 95% sensitive in detecting angiogram-positive disease, and almost 100% specific in identifying apparently healthy individuals. An ABPI of 0.9 or less is believed to be associated with 50% or greater vessel stenosis. The incidence of IC varies depending on the methodology used to define it, but there is a general pattern of a gradual increase in incidence up to the age of at least 70 years. For a chronic disease, the prevalence is a more relevant indicator of how common it is. The prevalence of IC is 3% to 6% in men aged 60 years and increases with age. The prevalence of asymptomatic PAOD may be as high as 20% in the adult population, using noninvasive testing. This is important because, as will be seen in later articles, PAOD, whether symptomatic or asymptomatic, is a serious risk factor for cardiovascular morbidity and mortality.

Adult↗
PubMed1999

Predictors of early disease in the lower limbs.

Increasing age and male gender are unavoidable risk factors for peripheral arterial occlusive disease (PAOD). A number of studies have looked at classical risk factors for atherosclerosis, such as diabetes, hypertension, lipid abnormalities, and smoking, as well as some more recently identified associations, such as plasma fibrinogen levels, impaired glucose tolerance, and hyperhomocysteinemia. However, most "risk factors" are really associations. A causal relationship may only reasonably be firmly established if a prospective controlled study shows that removing the risk factor significantly alters the course of the disease, as with smoking. Smoking is probably the strongest risk factor for intermittent claudication (IC), but hyperhomocysteinemia also appears to be strongly associated with the development of PAOD. Moderate alcohol intake and regular physical exercise appear to have a protective effect. A genetic risk factor is suggested but not as yet confirmed. The magnitude of the association varies from odds ratios of 2 to 3 for smoking and diabetes. There is insufficient evidence for hyperhomocysteinemia, but the effect may be even greater. The association with hypertension and lipid abnormalities is surprisingly inconclusive.

Adult↗
PubMed1999

Lower-extremity arteriosclerosis as a reflection of a systemic process: implications for concomitant coronary and carotid disease.

Peripheral arterial occlusive disease (PAOD), coronary artery disease (CAD), and cerebrovascular disease (CVD) are all manifestations of atherosclerosis or atherothrombosis, and therefore it is not surprising that the three conditions commonly occur together. Knowledge of the magnitude of co-existing cardiovascular disease and its prognosis is essential for the physician treating IC so that he can treat the local disease in its systemic context. The prevalence of CAD in patients with IC is 40% to 60%, although this may be asymptomatic and increases with the severity of the PAOD. Not surprisingly, the converse is also true; among individuals with CAD, the prevalence of PAOD is higher than in non-CAD individuals. The link between PAOD and CVD seems to be weaker than that with CAD, but again up to 60% of claudicants have some evidence of CVD. The prevalence of patients with CVD increases as the ABPI decreases. The evidence available from all of the relevant studies suggests that approximately 60% of patients with PAOD will have significant disease in the cardiac or cerebral circulation, and approximately 40% of patients with coronary disease or significant cerebral circulatory disease also will have PAOD.

Adult↗
PubMed1999

The natural history of claudication: risk to life and limb.

Although a patient with intermittent claudication (IC) will fear progression to severe disease and amputation, this is a relatively rare outcome of claudication, with only 1% to 3% of claudicants ever requiring major amputation over a 5-year period. Indeed, in one study, 50% of claudicants became symptom free during 5 years' follow-up. All the new evidence over the last 40 years has not altered the impression that only about one fourth of patients with IC will ever significantly deteriorate, and that deterioration is most frequent during the first year after diagnosis (6 to 9%) compared with 2% to 3% per annum thereafter. Smoking is the most important risk factor for the progression of local disease in the legs, with an amputation rate 11 times greater in smokers than nonsmokers. Diabetes, male gender, and hypertension are also important risk factors for progression. Because cerebrovascular disease (CVD), coronary artery disease (CAD), and peripheral arterial occlusive disease (PAOD) coexist, PAOD and IC should be regarded as a marker for increased risk from fatal and nonfatal cardiovascular event, and 2% to 4% of claudicants have a nonfatal cardiovascular event every year. The risk is higher in the first year after developing IC than in a long-standing stable claudicant, and the average claudicant is more likely to have a nonfatal myocardial infarction (MI) or stroke in the next year that of ever requiring a major amputation for his leg ischemia. The mortality in claudicants is 30% at 5 years, 50% at 10 years, and 70% at 15 years, without any clear decrease in these figures over the last 30 to 40 years. The mortality of claudicants is approximately two and a half times that of an age-matched general population.

Adult↗
PubMed1999

Predicting which patients will develop chronic critical leg ischemia.

Although numerically far less than claudicants, patients with critical leg ischemia (CLI) demand a disproportionately large commitment both in medical effort and economically and represent the major workload for vascular surgical units. The incidence and prevalence of CLI is approximately 500 to 1,000/million/year. The risk factors for the development of CLI are largely the same as those for the progression of local disease in IC, the most important, apart from age, being smoking and diabetes. Major amputation is more common amongst claudicants who are heavy smokers and who continue to smoke, and although stopping smoking slows down the vascular changes and reduces the likelihood of symptomatic progression, it does not reduce the risk of major amputation over the following 2 to 3 years. Diabetic PAOD patients are about 10 times more likely to come to amputation than nondiabetic PAOD patients, and the prevalence of gangrene is 20 to 30 times higher in individuals with diabetes and PAOD compared with nondiabetics with PAOD. There is some evidence that most of these effects of risk factors are additive.

Age Factors↗
PubMed1999

The fate of patients with critical leg ischemia.

In some highly specialized and aggressive units, 90% of patients with critical leg ischemia (CLI) will undergo some form of surgical or endovascular procedure; however, in most, the figure is nearer 50 to 60%. The primary amputation rate varies from around 10% to 40%. The mortality rate in these patients with standard therapy is around 20% at 1 year and between 40% and 70% at 5 years. Virtually all (95%) patients who present with ischemic gangrene, and 80% of those presenting with rest pain, are dead within 10 years. There appears to be a decline in overall major amputation rates associated with a corresponding increase in revascularizations. However, although technical advances may have resulted in a steadying or even decrease in amputations, comparisons of total amputations over a longer period suggest an increase, presumably attributable to an aging population. Some forward projections predict that major amputations will be doubled in the next 30 years.

Aged↗
PubMed1999

Acute limb ischemia.

Although there is little information on the incidence of acute limb ischemia (ALI) in the general population, it is estimated to be 14 per 100,000 and to compose 10% to 16% of the vascular workload. Also, as surgical intervention has become an option for ALI, the numbers actually referred appear to be increasing. The two main causes of ALI are either an embolism or a thrombosis, and differentiation based on history and clinical examination alone may be clinically impossible in 10% to 15% of cases. However, with the advent of thrombolysis, the distinction between emboli and thrombotic occlusions has become less important from the point of view of management. The natural history of ALI has remained largely unchanged despite the advent of the Fogarty catheter and thrombolysis. Patients presenting with ALI continue to have a particularly severe short-term outlook both in terms of loss of the leg and mortality, with 30-day amputation rates of between 10% and 30% and a mortality rate of around 15%. A patient with an embolic cause for an ischemic leg is at a higher risk of death because of the associated underlying cardiac disease, whereas patients with a thrombotic cause are more likely to lose a limb. The fact that overall mortality rates after intervention for acute ischemia have not improved dramatically over the past 20 years no doubt reflects the severity of the underlying diseases in these high-risk patients.

Acute Disease↗
PubMed1999

Major amputations: clinical patterns and predictors.

The major amputation rate is approximately 200 to 500/million/yr and occurs in patients presenting with an acute onset of critical leg ischemia (CLI) rather than in patients who steadily progress through increasingly severe claudication to rest pain and ulcers. Diabetics, who form only 2% to 5% of the population, form 40% to 45% of all amputees. Although it is widely believed that a below-knee (BK) to above-knee (AK) amputation ratio of 2.5 is the minimum acceptable for units providing a lower limb amputation service, the ratio is in fact usually very much below the recommended figure. The data suggest that primary healing of BK amputations ranges from 30% to 92% and the reamputation rate from 4% to 30%. If a popliteal pulse is palpable, then there is only a 10% failure rate, and bleeding during the operation does not seem to predict healing. Of the 30% of BK amputees whose wounds do not heal primarily, about half will need a higher major amputation, but once a BK major amputation has healed, only 4% of such patients ever need a higher amputation. A total of 90% of AK major amputations heal, 70% primarily. Two to three times as many BK amputees achieve full mobility than AK amputees, and there has not been any dramatic change in 20 years. The fate of the amputee 2 years after a successful BK amputation will be that 15% will have been converted to an AK amputation, another 15% will have had a contralateral major amputation, and 30% will be dead.

Acute Disease↗
PubMed1998

Prospective randomized controlled trial comparing Lichtenstein with modified Bassini repair of inguinal hernia.

We present a prospective randomized study of 80 patients with inguinal hernia who underwent either a modified Bassini repair (n = 38) or a Lichtenstein mesh repair (n = 42). Treatment groups were matched for age, side of hernia, type of hernia and ASA grade. There was no difference in the time taken to perform the two operations: the mean time taken to perform Lichtenstein repair was 26.8 min (range 12 to 49), Bassini repair taking a mean of 27.5 min (range 9 to 51), P = 0.76. There was, however, a difference between the operating times with respect to the type of hernia present, direct hernias being the fastest to repair. Pain scores were assessed by a visual analogue scale, and there was significantly less pain in the Lichtenstein group, P = 0.028. Despite this, there was no difference between the analgesic requirements of the two groups, P = 0.073. In order to assess rehabilitation, lengths of time not working and not driving were assessed. There was no difference in either measurement, P = 0.335 and 0.467 respectively. Patients were followed up a mean of 7 weeks post-operatively (range 1 to 13 weeks). There was no significant difference between the two procedures with regard to post-operative urinary complications, wound infection or other complications. All measurements except the time taken to perform the operation were independent of the surgeon involved. The accuracy of the clinical diagnosis was also assessed, and found to be moderate, with 63% of diagnoses being correct.

Adolescent↗