Search PubMed⌕ Search

Biomedical subjects

J Goldstone

Publications and source records attributed to J Goldstone.

At least 37 records · Page 2Linked to original sources
PubMed1994

Assessment of respiratory muscle strength in the intensive care unit.

The measurement of respiratory muscle strength in the intensive care unit (ICU) is potentially useful for the prediction of weaning outcome. An easy and accurate measure would also allow investigation of respiratory muscle weakness in critically ill patients. At present, there is no satisfactory method of strength measurement in the intensive care unit. Vital capacity is a nonspecific, volitional and relatively insensitive measure of strength. True maximum respiratory pressures are difficult to achieve and, in stable patients, results vary greatly both over time and between observers. For these reasons, there are few good data of respiratory muscle strength in the intensive care unit. Of the new techniques being developed, magnetic stimulation of the phrenic nerves, combined with the measurement of transdiaphragmatic, oesophageal, or endotracheal tube pressure, offers the greatest promise.

Humans↗
PubMed1993

Efficacy of carotid endarterectomy for asymptomatic carotid stenosis. The Veterans Affairs Cooperative Study Group.

BACKGROUND: The efficacy of carotid endarterectomy in patients with asymptomatic carotid stenosis has not been confirmed in randomized clinical trials, despite the widespread use of operative intervention in such patients. METHODS: We conducted a multicenter clinical trial at 11 Veterans Affairs medical centers to determine the effect of carotid endarterectomy on the combined incidence of transient ischemic attack, transient monocular blindness, and stroke. We studied 444 men with asymptomatic carotid stenosis shown arteriographically to reduce the diameter of the arterial lumen by 50 percent or more. The patients were randomly assigned to optimal medical treatment including antiplatelet medication (aspirin) plus carotid endarterectomy (the surgical group; 211 patients) or optimal medical treatment alone (the medical group; 233 patients). All the patients at each center were followed independently by a vascular surgeon and a neurologist for a mean of 47.9 months. RESULTS: The combined incidence of ipsilateral neurologic events was 8.0 percent in the surgical group and 20.6 percent in the medical group (P < 0.001), giving a relative risk (for the surgical group vs. the medical group) of 0.38 (95 percent confidence interval, 0.22 to 0.67). The incidence of ipsilateral stroke alone was 4.7 percent in the surgical group and 9.4 percent in the medical group. An analysis of stroke and death combined within the first 30 postoperative days showed no significant differences. Nor were there significant differences between groups in an analysis of all strokes and deaths (surgical, 41.2 percent; medical, 44.2 percent; relative risk, 0.92; 95 percent confidence interval, 0.69 to 1.22). Overall mortality, including postoperative deaths, was primarily due to coronary atherosclerosis. CONCLUSIONS: Carotid endarterectomy reduced the overall incidence of ipsilateral neurologic events in a selected group of male patients with asymptomatic carotid stenosis. We did not find a significant influence of carotid endarterectomy on the combined incidence of stroke and death, but because of the size of our sample, a modest effect could not be excluded.

Adult↗
PubMed1993

Preoperative and intraoperative factors associated with prolonged mechanical ventilation. A study in patients following major abdominal vascular surgery.

A study of 51 patients undergoing elective major abdominal surgery was carried out to determine the incidence of postoperative respiratory failure requiring mechanical ventilation for more than 24 h and which preoperative and intraoperative factors are associated with this respiratory complication. Mechanical ventilation for more than 24 h was required in 12 of the 51 patients. These 12 patients had a significantly longer stay in the intensive care unit and in the hospital than the patients who were successfully extubated in the postoperative period. Also, there was a trend for a higher mortality in the ventilated group compared to the group of patients who did not require postoperative ventilation. Preoperative abnormalities in FEV1 did not identify which patients were destined to require postoperative ventilation. Significant differences for the ventilated versus the nonventilated patients included a longer history of cigarette smoking, a lower preoperative PaO2, and a large intraoperative blood loss.

Abdomen↗
PubMed1993

Failure of glow-discharge polymerization onto woven Dacron to improve performance of hemodialysis grafts.

PURPOSE: The ideal conduit for hemodialysis vascular access remains elusive. Autogenous fistulas and prosthetic grafts, most commonly expanded polytetrafluoroethylene (e-PTFE), have adequate long-term patency rates (60% to 80% at 1 year); however, considerable delay in their use (2 to 6 weeks) is required. The Plasma-TFE graft is a recently introduced thin-walled woven Dacron graft to which an ultrathin layer of tetrafluoroethylene is bonded through a process of glow-discharge polymerization. This process purportedly results in a graft with an internal surface of low thrombogenicity. Low thrombogenicity, combined with the healing characteristics of a woven graft, have led to claims of equivalent patency rates even when used for dialysis immediately (within 1 week) after implantation. METHODS: This concept led us to use this new graft material in 19 fistulas (12 forearm and 7 arm) during a 1-year period. RESULTS: Although early use was possible, the primary and secondary patency rate at 12 months was only 47.4%. Ten grafts required replacement, five within the first month and two in the second month. Attempts at fistula revision failed because of unsuccessful graft thrombectomy or exuberant intimal hyperplasia. Failure was not associated with early use. During the same time period, 28 PTFE grafts were implanted, with only four failures (primary patency 78.6%; secondary patency 85.7%; p = 0.028). The secondary patency rate was the same for Plasma-TFE grafts (47%) but improved to 85.7% for e-PTFE grafts (p = 0.005). Both groups were comparable with respect to age, diabetes, previous dialysis access procedures, and other comorbid conditions. CONCLUSIONS: These early results have been sufficiently disappointing that we have abandoned use of this graft approved for hemodialysis by the Food and Drug Administration and cannot recommend it for other clinical indications. Nevertheless, the concept of plasma-discharge polymerization is theoretically attractive and might be useful in future graft configurations.

Adult↗
PubMed1993

Prevention and treatment of foot problems in diabetes mellitus. A comprehensive program.

This discussion was selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from a transcription, it has been edited by Nathan M. Bass, MD, PhD, Associate Professor of Medicine, under the direction of Lloyd H. Smith, Jr, MD, Professor of Medicine and Associate Dean in the School of Medicine.

Aged↗
PubMed1992

Elderly, conscious patients have an accentuated hypotensive response to nitroglycerin.

There is no adequate explanation for the highly variable response of systemic blood pressure to nitroglycerin (glyceryl trinitrate [GTN]). Aging produces cardiovascular changes that should alter the effects of GTN, but elderly patients usually have been excluded from studies of GTN. Accordingly, the authors compared the effects of GTN on systemic blood pressure in elderly and younger patients. Fifty-three patients, aged 49-87 (with 30 patients older than 70), were studied. Before elective vascular surgery, 14 patients received an infusion of placebo; 26, a constant infusion of GTN; and 13, a stepwise increasing infusion of GTN. After a standardized anesthetic induction and the start of surgery, the identical infusion protocols were repeated in each group. Data on GTN infusion rate, arterial blood pressure, and GTN concentrations versus time, age, and other potentially influencing variables were pooled for analysis. Before anesthesia and surgery, GTN more commonly caused excessive hypotension in patients older than 70 yr than in younger patients, but none of the patients had complications. A repeated-measures model analysis indicated that age significantly influenced the effects of GTN on blood pressure. That is, patients who are in their 70s who receive 0.5 micrograms.kg-1.min-1 of GTN are predicted to experience a twofold greater decrease in systolic arterial pressure (approximately 33 mmHg) than patients in their 50s. However, no apparent effect of age on intraoperative GTN responsiveness was discernible nor was a predictable relationship found between the preoperative and intraoperative responsiveness or between arterial concentrations of GTN and blood pressure or age. Therefore, the authors conclude that, in the absence of the effects of anesthesia and surgery, elderly patients have a more pronounced blood pressure response to GTN than younger patients. Furthermore, the authors conclude that preoperative blood pressure responsiveness to GTN is not a reliable predictor of intraoperative responsiveness.

Aged↗
PubMed1990

Can duplex scanning replace arteriography for lower extremity arterial disease?

This preliminary study was undertaken to determine if surgeons would choose different intervention for lower extremity occlusive disease when given basic clinical information and data from either a duplex scan or arteriogram. Information on degree of stenosis from duplex scans and arteriograms of 29 patients was indicated on an anatomical line drawing along with the ankle blood pressures and a brief clinical description. Based on these data sheets, six vascular surgeons chose a clinical plan in a blinded fashion for each patient. Each plan was placed into one of eight possible categories for comparison using the kappa statistic. Intraobserver agreement between surgeons' decisions based on duplex scanning versus those based on arteriography was very good (mean kappa .70 with exact agreement in 76%). Interobserver agreement between different surgeons' decisions based on the same studies was significantly less (mean kappa 0.56, p less than .05). Significant disparity in clinical approach occurred in 43% of the patients with nearly identical duplex scan and arteriogram reports, suggesting that much of the discrepancy lies in the clinical decision-making process. Clinical decisions made using duplex scans are very similar to those made using arteriograms. This technique can limit the need for arteriography in assessing patients with lower extremity arterial occlusion disease.

Angiography↗
PubMed1990

Examination of vascular anastomoses during liver transplantation by intraoperative Doppler duplex scanning.

Intraoperative examination of the arterial and portal vein anastomoses was performed in 16 liver transplant patients using duplex scanning. Two major defects and three minor defects were found in 5 arterial anastomoses. Major defects were defined as those associated with an audibly abnormal Doppler signal, a defect greater than 3 mm in length or greater than 50% luminal narrowing. Minor defects were defects visible by ultrasound but not meeting the above criteria. The major defects were repaired and scans following repair were without evidence of defects. The three minor defects were ignored. A nearly occluding thrombus was found in the portal vein of one patient. A thrombectomy was performed successfully. All patients have done well postoperatively. This report suggests that intraoperative duplex scanning may be of value in detecting technical imperfections in the vascular anastomoses during liver transplantation. Detection of a major defect intraoperatively allows immediate repair.

Adult↗
PubMed1990

Recurrent carotid stenosis: a consequence of local or systemic factors? The influence of unrepaired technical defects.

To determine the influence of unrepaired technical defects as well as systemic risk factors for atherogenesis on carotid artery healing after endarterectomy, we conducted a prospective study using intraoperative duplex scanning with spectral analysis to establish the initial status of the artery (N = 131 arteries), and then we studied these vessels at regular postoperative intervals with the same technique (N = 108 arteries, 265 studies). The vessels were divided into the operated and nonoperated segments of the common, internal, and external carotid arteries, and both intraoperative image and flow data were tabulated by artery segment. The technical factors that were analyzed included defect size, defect type, adjacent segment defects, number of defects, shunt use, vessel reopening, and peak, mean, and end-diastolic frequency and velocity. The systemic risk factors studied were sex, hypertension, diabetes, smoking, randomly drawn total serum cholesterol and triglyceride levels, and perioperative aspirin and dextran use. Data were analyzed by linear logistic regression analysis. Among the technical factors, only intraoperative defect size was significantly associated with risk of recurrent stenosis (p = 0.0175). Although any defect size adversely affected the condition of the vessel during follow-up, the magnitude of this effect was small for smaller defects (size category 1: less than or equal to 40% stenosis or flap length less than or equal to 25% of vessel diameter). The systemic factors that were associated with risk of recurrent stenosis were hypertension (p = 0.0002), smoking (p = 0.0016), and randomly drawn total serum cholesterol level (p = 0.0116). The fact that the operated segments consistently fared worse during follow-up than did the nonoperated segments (p = 0.0044) undoubtedly reflects the inevitable trauma of the endarterectomy, but also emphasizes the important contribution of systemic risk factors in recurrent carotid stenosis. Risk factor modification may be the most effective method of ensuring the durability of carotid endarterectomy.

Carotid Artery Diseases↗