Search PubMed⌕ Search

Biomedical subjects

J R Evans

Publications and source records attributed to J R Evans.

At least 19 recordsLinked to original sources
PubMed1992

The "health of the public" approach to medical education.

The author examines the growing discontinuity between medical education and the general health needs of society. He explains and illustrates this failure of the academic medical center in several ways: by a parable; by reporting the results of his informal survey of faculty and residents; by presenting the findings of an international conference on medical education; and by giving a detailed description of the design and impact of the "Health of the Public" program, launched by the Pew Charitable Trusts and the Rockefeller Foundation in 1986. He maintains that there is an imbalance in the training of physicians and other health professionals because academic medical centers are dominated by supply-side thinking--which is driven by new knowledge and technology and the resulting need to find patients to fit the interests and technical capabilities of specialists and the equipment and services of hospitals--and have under-emphasized demand-side thinking, which concerns the patient and the health expectations, needs, and trends in the community. The author maintains that academic medical centers can continue to achieve the recognition they seek, but can do so by making the changes needed to better balance the driving forces of supply and demand. Only by doing this will they fulfill their fundamental mission of fostering the health of the public.

Academic Medical Centers↗
PubMed1991

Management of infected aortoiliac aneurysms.

A 30-year retrospective review identified 13 patients treated for infected aneurysms of the abdominal aorta or iliac arteries, for an overall incidence of 0.65%. A constellation of clinical findings led to the correct preoperative diagnosis in 11 (85%) of 13 patients. Treatment methods included resection and in situ replacement grafting in seven patients, resection and extra-anatomic bypass in five patients, and resection-ligation in one patient. Four (31%) of 13 patients died within 30 days of operation, three of whom died of rupture. Overall, good results were achieved in five patients (38%), while poor results were noted in the remaining eight patients (62%). The determinants of outcome were aneurysm location or rupture, the presence of established infection, and the virulence of the infecting organism. In 10 (77%) of the 13 aneurysms, Salmonella species, Bacteroides fragilis, Staphylococcus aureus, and Pseudomonas aeruginosa accounted for all deaths, ruptures, and suprarenal aneurysm infections. These data suggest that patients with primary infections of the abdominal aorta or iliac arteries continue to present with advanced infections or aneurysm rupture that result in a high mortality.

Adult↗
PubMed1991

Left flank retroperitoneal exposure: a technical aid to complex aortic reconstruction.

Over the last 5 years an extended left flank retroperitoneal approach was used in 85 of 531 (16%) aortic reconstructions deemed technically complex. Abdominal aortic aneurysm repair was performed in 70 patients (82%), bypass of aortoiliac occlusive disease was performed in 11 (13%), and aortic endarterectomy for mesenteric and/or renovascular disease was performed in 4 (5%). Indications for use of this approach included a "hostile" abdomen (43 patients), juxta/suprarenal abdominal aortic aneurysm (35), large (greater than 10 cm) abdominal aortic aneurysm (12), extreme obesity (10), associated renal and/or visceral artery stenosis requiring endarterectomy (9), inflammatory abdominal aortic aneurysm (2), and horseshoe kidney (2). Suprarenal or supraceliac aortic clamping, averaging 31 minutes, was required in 43 patients (50%). Postoperative recovery was rapid (average length of stay, 10.2 days), and morbidity was minimal despite the complex nature of these reconstructions. The perioperative mortality rate in elective operations was 1.2%. This approach facilitated proximal abdominal aortic exposure and anastomosis, especially in large, pararenal aneurysms or in situations unfavorable to a transabdominal approach. Whereas a left flank retroperitoneal approach can be used in most aortic reconstructions, it seems especially suited to those that pose significant technical challenges.

Abdomen↗
PubMed1990

The use of routine referral data in the development of clinical audit and management in North Lincolnshire.

As part of the national waiting list initiative, a retrospective survey of routine referrals in seven specialties to Lincoln County Hospital by general practitioners within its catchment area, during the months of January to March 1987 inclusive, was carried out, using data from the hospital's Patient Administration System and the Lincolnshire Family Practitioner Committee. These specialties were identified by managers and clinicians as those in which a significant problem of waiting times and waiting lists existed, both as perceived locally and in comparison with other districts. The total referral rate for all GPs in the study was 9.6 referrals/100 patients on their list/year, which is very close to the average of other studies published elsewhere in the country on this topic. However, the range of referral rates between practices was very wide, varying from 2.8 to 17.6. There were also wide variations within individual practices. It is therefore concluded that, taken overall, 'over-referral' by general practitioners is not the cause of any problem at Lincoln County Hospital. However, the wide variation of referral patterns has been of great interest to the general practitioners themselves. They have requested that referral rates be fed back to them routinely, in the manner of the Prescription Pricing Authority, and this will commence shortly. In addition, a working group of orthopaedic surgeons and general practitioner representatives has met to discuss the implications of the study, and the drawing up of mutually agreed referral protocols, the operation of which would be monitored jointly. The setting up of similar groups in the other specialties is under active consideration.

Catchment Area, Health↗
PubMed1990

Inorganic sulfate metabolism in the very low birthweight infant.

The effect of vitamin D supplementation on inorganic sulfate metabolism was examined in very low birth weight (less than 1,500 g) infants at biweekly intervals after birth until 6 weeks of postnatal age. Baseline serum sulfate concentrations were significantly higher in all infants (471 +/- 24 mumol/l, n = 80) than in adults (299 +/- 25 mumol/l, n = 17). In controls, the levels did not change significantly over the ensuing 6 weeks, although serum creatinine declined. Urinary sulfate excretion rose significantly to near adult levels by 2 weeks. Both urine and serum sulfate were correlated with weight gain but not with estimated glomerular filtration rate, suggesting that factors other than renal clearance have a preponderant influence on serum sulfate in these infants. At 6 weeks, the mean serum sulfate in the high-dose group (receiving 2,170 +/- 23 U/day of vitamin D, n = 41) was significantly higher than in controls (receiving 360 +/- 22 U/day, n = 40). In all infants, there was a significant correlation (r = 0.36, p less than 0.001) between serum sulfate and 25(OH)-vitamin D concentrations, but not other analytes or clinical variables, suggesting that vitamin D may be one of the factors modulating sulfate metabolism in the newborn period.

Creatinine↗
PubMed1990

Discriminant functions in differential diagnosis of hypercalcemic patients.

Using readily available biochemical assays of plasma and urine constituents, we have defined discriminant functions useful as a guide to the differential diagnosis of patients with hypercalcemia. The decreasing rank order of contribution of the variables to the discriminant functions was as follows: plasma albumin, plasma phosphate, plasma chloride, log10 (calcium excretion per liter of glomerular filtrate), and log10 (plasma gamma-glutamyltransferase). Discriminant functions have been defined for patients with values for plasma creatinine above and below 185 mumol/L, and for practical conditions in which plasma and urine samples, or plasma samples only, are available.

Calcium↗
PubMed1990

Ureteral complications and aortoiliac reconstruction.

A 33-year experience with 58 ureteral complications in 50 of 3580 patients undergoing aortoiliac reconstruction was analyzed. Ureteral obstruction was treated before or in conjunction with aneurysm repair in six patients with aneurysmal disease. The remaining 44 patients had 46 ureteral complications after aortic reconstruction; complications included hydronephrosis (42), ureteral leak (3), and ureteral necrosis (1). A high incidence of associated graft complications was noted. Graft thrombosis developed in one of the six patients undergoing prior or simultaneous ureteral procedures, and graft infection developed in another. Thirty-six graft complications developed in 24 (55%) of the 44 patients with postoperative ureteral complications. The complications included 19 anastomotic aneurysms, eight graft limb thromboses, six graft infections, and three aortoenteric fistulas. Twenty-nine of the 44 patients with postoperative ureteral complications underwent ureteral or graft operations or both. These included five patients having ureteral operations alone, seven with a ureteral procedure and subsequent graft operation, eight requiring simultaneous ureteral and graft procedures, and nine undergoing a graft operation with ureteral observation. Six of these 29 patients (21%) died after operation, all from graft complications including aortoenteric fistulas (three), ruptured anastomotic aneurysms (two), and graft infection (one). Graft complications affected 55% of 44 patients with postoperative ureteral complications, compared to 12% of 3536 patients without ureteral complications (p less than 0.0001). Patients with postoperative ureteral complications were 4.4 times as likely to have graft complications compared to those without ureteral complications (p less than 0.0001). These data suggest that such urologic complications may be markers for recognition of or harbingers for graft complications.

Adult↗
PubMed1990

Hyponatremia in patients admitted to a coronary care unit.

Calculation of osmolal gap in plasma and urine samples from patients after acute myocardial infarction was carried out to see whether changes in these variables support the concept of a "sick-cell" mechanism being responsible for the hyponatremia associated with acute myocardial infarction. Some supportive evidence was found on the first day after admission but, overall, the evidence was not convincing.

Diuretics↗
PubMed1989

Drug errors and incidents in a neonatal intensive care unit. A quality assurance activity.

We prospectively examined the causes of medication errors and incidents in a level 3 neonatal intensive care unit for a 2-year period. There were 313 incidents in 23,307 patient days (13.4 incidents per 1000 patient days). The relative risk of incidents was greater in more intensive levels of care. The two most common causes of incidents were neglecting to give a medication on schedule (n = 52) and nonregulation of an intravenous infusion (n = 32). Twenty percent of orders made by physicians that were in error resulted in serious incidents compared with only 6% of all other causes.

Drug Administration Schedule↗
PubMed1989

Effect of high-dose vitamin D supplementation on radiographically detectable bone disease of very low birth weight infants.

To test the hypothesis that high-dose vitamin D2 supplementation would result in a lower incidence of radiographically detectable bone disease, we randomly assigned 40 very low birth weight infants to a control group who received vitamin D2 in a dosage of 400 IU/day and 41 to an experimental group who received a dosage of 2000 IU/day. After 6 weeks, radiographs from all infants were scored blindly for degree of radiographic bone disease, and serum osteocalcin and 25-hydroxyvitamin D levels were measured. Mean vitamin D intake was 360 +/- 141 (SD) IU/day in the control group and 2170 +/- 144 (SD) IU/day in the experimental group. Median 6-week serum 25-hydroxyvitamin D levels were 24 ng/ml (range 3 to 60 ng/ml) in the control group and 68 ng/ml (range 9 to 150 ng/ml) in the experimental group (p less than 0.001). Overall, 20% of the infants had evidence of moderate radiographic bone disease and only 2% were severely affected. The radiographic bone score (median = 2.5) and serum osteocalcin concentration (mean = 21.7 +/- 8.7 ng/ml) in the control subjects did not differ significantly from those in the experimental group (median bone score = 2.0; mean osteocalcin level = 24.1 +/- 7.9 ng/ml). Although there may be a subset of very low birth weight infants who would benefit from high doses of vitamin D, we conclude that no generalized clinical improvement can be attributed to this regimen alone.

Bone Diseases↗
PubMed1989

Mandibulotomy: a surgical approach to oral and pharyngeal lesions.

The history of mandibulotomy is reviewed. The surgical steps involved and the variations of techniques are discussed. Two illustrative cases are reported and the clinical applications of the approach are discussed. It is concluded that mandibulotomy has a place in the management of malignancies as well as awkwardly situated benign lesions as well as malignancies.

Adult↗
PubMed1988

Pharmacokinetics of iothalamate in endstage renal disease.

Some nephrologists make alterations in routine peritoneal and hemodialysis schedules after diagnostic studies that use radiographic contrast agents. A study to determine the pharmacokinetics of one contrast agent, iothalamate, is reported. The plasma (total body) clearance of iothalamate was measured in seven patients who had endstage renal disease (ESRD) and who received maintenance hemodialysis. During an interdialytic period, plasma clearance of iothalamate varied from 0.7 to 5.2 mL/min (3.1 +/- 1.8 mL/min, mean +/- SD) with an elimination rate constant (beta) of 0.0164 +/- 0.01 hr-1, a terminal half-life of 61 +/- 42 hours, and an estimated distribution volume of 11 +/- 3.9 L. Hemodialysis clearance of iothalamate was 104 +/- 54 mL/min. With the assumption that iothalamate is mainly distributed in the extracellular fluid (ECF) compartment, the theoretical fluid shift from the intracellular fluid (ICF) compartment to the ECF compartment was 323 mL after administration of the largest dose (2.1 mL/kg or 1.6 mmol/kg of body weight) of 60% meglumine iothalamate solution. The average maximum serum osmolarity change was less than expected, suggesting some type of internal buffering of meglumine iothalamate. In the first few hours after radiocontrast administration in four patients, the average change in serum osmolarity was 5 mmol/L; the average change in serum sodium concentration during this same time was a decrease of 0.5 mmol/L. The minor increase in ECF volume induced by hyperosmolar contrast agents does not require immediate dialysis in most patients. When needed, however, for contrast-related adverse effects, hemodialysis is efficient in rapidly removing iothalamate.

Aged↗
PubMed1988

Effect of timing of cerebral ultrasonography on the prediction of later neurodevelopmental outcome in high-risk preterm infants.

To determine the predictive value of cranial ultrasonographic examination in high-risk preterm infants at different postnatal ages, we scanned 110 infants less than or equal to 32 weeks gestational age at 1, 2, 3, and 6 weeks postnatal ages and at 40 weeks postconceptional age (PCA). Cranial abnormalities detected by ultrasonography at each postnatal age of examination were classified as minor (periventricular superolateral echogenicity with or without intraventricular hemorrhage, grades 1 to 3) or major (cystic periventricular leukomalacia with or without intraventricular hemorrhage, grade 4) and correlated with neurodevelopmental outcome determined by 1 year of age. Major abnormalities detected by ultrasonography were present in four infants at 1 week, four at 2 weeks, eight at 3 weeks, and 11 infants at 6 weeks and 40 weeks PCA, respectively. Nineteen infants (17%) had moderate to severe functional handicaps defined as cerebral palsy, cognitive or visual deficit, or deafness. The positive and negative predictive values of ultrasound examinations, with regard to later neurodevelopmental outcome, improved with increasing postnatal age at examination and was best at 40 weeks PCA. Negative results of ultrasound study at 40 weeks PCA most correctly predicted satisfactory outcome. Although only 58% of moderately to severely handicapped infants were correctly identified by ultrasound examination at 40 weeks PCA, all infants with major ultrasonographic abnormalities at 40 weeks PCA had moderate or severe handicap. Our data demonstrate that the timing of cerebral ultrasonography is important in the prediction of later neurodevelopmental outcome in high-risk preterm infants.

Age Factors↗
PubMed1988

White clot syndrome.

Heparin therapy is currently a vital component in the medical management of thromboembolic events. Despite its widespread use, it is associated with relatively few complications, and these are usually minor and quickly reversible. Recently a much more dramatic and serious complication of heparin therapy has been identified. In heparin-induced thrombocytopenia with associated thrombosis or "white clot syndrome," patients have paradoxic thromboembolic events while receiving heparin. These events are of acute onset and of major consequence, often resulting in limb loss or death. This paper describes our own experience with ten patients in whom the white clot syndrome occurred during heparin therapy for thrombotic or embolic events. Both porcine and bovine heparin preparations were being given through various routes. In the three cases in which platelet aggregation testing was completed, results were positive. Our ten patients ultimately had a 20% major limb amputation rate and an overall 50% mortality.

Aged↗
PubMed1987

The effect of renal function on the pharmacokinetics of gemfibrozil.

STUDY OBJECTIVE: to determine the effect of renal function on the pharmacokinetics of gemfibrozil following single and multiple oral doses. DESIGN: nonrandomized; paired studies of single versus multiple doses. SETTING: patients enrolled in a veterans hospital renal subspecialty clinic. PATIENTS: 17 male patients 57 to 74 years old selected for various levels of renal function, including end-stage renal disease. INTERVENTIONS: patients initially received 600 mg of oral-gemfibrozil followed by sequential venous blood sampling. Seven to 14 days later, the patients started receiving gemfibrozil, 600 mg bid. Venous blood samples were obtained over the following 10 days and frequently during a 24-hour washout phase. MEASUREMENTS AND MAIN RESULTS: peak gemfibrozil concentrations (mg/L) were 11.1 (3.9 SD) for the single dose and 10.2 (3.8) for the multiple-dose study. Time to peak concentration (hr) was 2.1 (1.0) and 1.8 (0.6), respectively. The mean half-life of elimination (hr) from the single-dose study was 6.4 (11.8) compared with the multidose study of 3.0 (3.1), which did not reach statistical significance (P = .25). The difference between the area under the curve for the single versus the multiple-dose study approached statistical significance (P = .054). The coefficient of determination for creatinine renal clearance versus the plasma clearance of oral gemfibrozil was 0.009 (P = .72) for the single-dose regimen and 0.331 (P = .016) for the multiple-dose study. CONCLUSION: the half-life of gemfibrozil is independent of renal function for both single- and multiple-dose regimens. Dosing schedules do not require alteration for renal insufficiency.

Aged↗