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Biomedical subjects

C R Smith

Publications and source records attributed to C R Smith.

At least 253 records · Page 14Linked to original sources
PubMed1986

Studies of risk factors for aminoglycoside nephrotoxicity.

The epidemiology of aminoglycoside-induced nephrotoxicity is not fully understood. Experimental studies in healthy human volunteers indicate aminoglycosides cause proximal tubular damage in most patients, but rarely, if ever, cause glomerular or tubular dysfunction. Clinical trials of aminoglycosides in seriously ill patients indicate that the relative risk for developing acute renal failure during therapy ranges from 8 to 10 and that the attributable risk is 70% to 80%. Further analysis of these data suggests that the duration of therapy, plasma aminoglycoside levels, liver disease, advanced age, high initial estimated creatinine clearance and, possibly, female gender all increase the risk for nephrotoxicity. Other causes of acute renal failure, such as shock, appear to have an additive effect. Predictive models have been developed from these analyses that should be useful for identifying patients at high risk. These models may also be useful in developing insights into the pathophysiology of aminoglycoside-induced nephrotoxicity.

Acute Kidney Injury↗
PubMed1986

Endarterectomy for localized lesions of the superficial femoral artery at the adductor canal.

Although femoropopliteal bypass is the accepted treatment for diffuse atherosclerotic disease of the superficial femoral artery, endarterectomy may be appropriate for short segmental lesions at the level of the adductor tendon. Over a 25-year period, 94 patients underwent localized endarterectomy of short (less than 15 cm) segments of the distal superficial femoral artery. There were two perioperative deaths in the series, for an operative mortality rate of 2.1%. The long-term patency rate was substantial, with 66% of the reconstructions open at 3 years and 57% open 7 years after operation. Improved results were obtained when a semiclosed method was possible with a transverse distal arteriotomy to prevent subintimal dissection. There was a trend toward improved patency in patients with claudication and those who underwent endarterectomies less than 7.5 cm in length. Patency appeared independent of popliteal outflow. Amputation was initially avoided in 82% of patients presenting with threatened limbs. These results suggest that superficial femoral endarterectomy may be a viable alternative to femoropopliteal bypass when the disease is localized to the adductor canal.

Adult↗
PubMed1986

A model for predicting nephrotoxicity in patients treated with aminoglycosides.

We have previously identified risk factors for nephrotoxicity in 204 patients receiving aminoglycosides. We added data on an additional 134 patients from the University of Chicago who were treated for longer periods (13.1 +/- 9.4 days) to determine if duration of therapy was also a risk factor. In the combined populations, nephrotoxicity developed in 59 (17.5%) of 338 patients, and duration of therapy was the factor most strongly associated with nephrotoxicity (P less than .0001). A new predictive model was developed that was then tested prospectively on 175 consecutive medical and surgical patients who had plasma levels of aminoglycoside measured. The new model accurately identified 14 of 15 patients with nephrotoxicity (sensitivity = 93%) and 106 of 160 without nephrotoxicity (specificity = 66%). A bedside scoring system accurately identified high-risk and low-risk patients. We believe these data add to the understanding of the clinical correlates of aminoglycoside nephrotoxicity and aid in the identification of high-risk patients.

Aminoglycosides↗
PubMed1986

Influence of hypothermia, barbiturate therapy, and intracranial pressure monitoring on morbidity and mortality after near-drowning.

We retrospectively evaluated the clinical and pathologic effects of hypothermia and high-dose barbiturate therapy on hypoxic/ischemic cerebral injury after near-drowning in children. Of 40 near-drowned patients admitted to the ICU, 13 died, seven had permanent cerebral damage, and 20 survived. Twenty-four patients (group 1) were treated with a regime of hyperventilation, hypothermia, and high-dose phenobarbitone while intracranial pressure (ICP) was continuously monitored. Of ten who died in this group, three were diagnosed as having cerebral death shortly after admission; autopsy revealed severe cerebral edema with herniation. The remaining seven nonsurvivors had severe cerebral hypoxia without raised ICP and had the features of severe adult respiratory distress syndrome and hypoxic/ischemic damage to other organs. Six of these seven patients developed septicemia which was invariably associated with a profound neutropenia. Sixteen patients (group 2) were treated with a similar protocol but without hypothermia. Three of these patients died but only one developed septicemia. Neutropenia after resuscitation from near-drowning seemed to indicate a poor prognosis; the mean polymorphonuclear leukocyte count in nonsurvivors (1.9 +/- 0.5 X 10(9) cell/L) was significantly (p less than .01) lower than that in survivors (6.4 +/- 1.1 X 10(9) cell/L). Hypothermia was associated with a decreased number of circulating PMNs but did not increase the number of neurologically intact survivors. Similarly, although barbiturates may control ICP, their use did not improve outcome. Because severe cerebral edema and herniation after near-drowning is usually associated with irreversible brain damage, measures to control brain swelling such as hypothermia and barbiturates will be of little benefit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Pressure sores among hospitalized patients.

A cross-sectional survey was done to determine the prevalence of pressure sores in hospitalized patients and the factors associated with having a pressure sore in the hospital. Among 634 adult patients, 30 (4.7%; 3.1% to 6.3%, 95% confidence interval) had a pressure sore and 78 (12.3%; 9.8% to 14.8%) were at risk for a pressure sore because they had been confined to a bed or chair for at least 1 week. Comparing these two groups of patients, we found that fecal incontinence, diarrhea, fractures, urinary catheter use, decreased weight, dementia, and hypoalbuminemia were associated with having pressure sores (p less than or equal to 0.05). Using logistic regression analysis, hypoalbuminemia, fecal incontinence, and fractures remained significantly and independently associated with having a pressure sore (odds ratios = 3.0, 3.1, and 5.2, respectively; p less than or equal to 0.05). Our findings suggest that 17% (14% to 20%) of hospitalized patients have pressure sores or are at risk for them, and that hypoalbuminemia, fecal incontinence, and fractures may identify bedridden patients at greatest risk.

Adult↗
PubMed1986

Computed tomography of hemangiomas and related soft-tissue lesions in children.

The varied computed tomographic (CT) appearances of 19 hemangiomas and related soft-tissue lesions in 17 children were assessed retrospectively. Good CT-tissue correlation was obtained in 11 patients in whom histology was available. Although most cutaneous vascular lesions can be diagnosed by their characteristic clinical features, their extent may be difficult to assess clinically and at surgery. CT is important in defining the extent of these lesions as a guide for the surgeon, and for conservative follow-up. The often characteristic CT appearances also help in the diagnosis of the few patients with unusual clinical presentations.

Adipose Tissue↗
PubMed1986

Cefotaxime vs nafcillin and tobramycin for the treatment of serious infection. Comparative cost-effectiveness.

To evaluate the cost-effectiveness of cefotaxime sodium at a dosage of 12 g/day vs nafcillin sodium and tobramycin sulfate for the treatment of serious infection, the hospital and physician charges of patients enrolled in a prospective, randomized, clinical trial were analyzed. For 187 patients receiving therapy empirically, mean hospital charges for the interval in which the trial antibiotics were used were $3,550 +/- $1,740 for cefotaxime and $3,160 +/- $1,990 for nafcillin and tobramycin. After adjusting for cost-generating factors, charges for cefotaxime were greater than for nafcillin and tobramycin, but the difference was not significant. For 107 patients with clinically or bacteriologically documented infection, mean charges were $3,980 +/- $1,800 for cefotaxime and $4,170 +/- $1,780 for nafcillin and tobramycin. Adjusted charges did not differ. Incremental charges for cefotaxime per additional response were $1,630 in all patients and -$820 in patients with clinically or bacteriologically documented infections.

Bacterial Infections↗
PubMed1986

Reversal of cardiac transplant rejection without massive immunosuppression.

Although cyclosporine has decreased the severity of acute cardiac transplant rejection, most centers have continued to use high-dose intravenous steroids to treat acute rejection. To minimize the morbidity of antirejection therapy, acute rejection episodes in 37 cardiac transplant recipients were treated prospectively with only a boost of oral prednisone. Cyclosporine was continued at the same maintenance dose while oral prednisone was increased to 100 mg/day for 3 days, then rapidly tapered over 1 week to the maintenance dose. Seventy-six of 85 acute rejection episodes (90%) showed histologic resolution of mycocyte necrosis on repeat biopsy. Three acute rejection episodes (3.5%) resolved only after "rescue therapy" with intravenous steroid, and an additional three episodes (3.5%) required the combination of intravenous steroid and rabbit antithymocyte globulin to effect resolution. In addition, three acute rejection episodes (3.5%) resulted in graft loss. This was fatal in two patients and one patient underwent successful retransplantation. Oral steroid therapy alone is adequate therapy for most acute rejection episodes in cyclosporine-treated heart transplant recipients, and low infectious morbidity and mortality has been associated with this antirejection protocol.

Adolescent↗
PubMed1985

Primary and secondary tumors of childhood involving the heart, pericardium, and great vessels. A report of 75 cases and review of the literature.

Between 1919 and 1981, 16 children with primary cardiac tumors (8 rhabdomyomas, 5 fibromas, 2 myxomas, and 1 rhabdomyosarcoma) and 59 children with secondary tumors of the cardiovascular system were seen at The Hospital for Sick Children in Toronto. Distant metastases in 45 children of the latter group, in descending order of frequency, were from non-Hodgkin's lymphoma, neuroblastoma, soft tissue and bone sarcoma, Wilms' tumor, and hepatoma, and involved the myocardium and pericardium. In the remaining 14 children, tumor thrombi from Wilms' tumor (9 cases), adrenal (2 cases) and hepatocellular carcinoma (2 cases), and endodermal sinus tumor (1 case) extended directly into the great veins and/or cardiac chambers. Children with primary and secondary tumors often present with nonspecific clinical, plain radiographic, electrocardiographic, and M-mode echocardiographic findings. Early recognition, utilizing special diagnostic procedures such as two-dimensional echocardiography, computerized axial tomography, angiocardiography, and inferior venocavography, followed by elective surgical resection of tumor under cardiopulmonary bypass and/or radiation and chemotherapy, offers patients with cardiovascular tumors the best chance of cure.

Angiocardiography↗
PubMed1985

Treatment of Raynaud's phenomenon with calcium channel blockers.

Raynaud's phenomenon may cause severe digital pain and functional disability, particularly in patients with underlying connective tissue diseases. The pathophysiology of Raynaud's phenomenon is varied, but digital ischemia is an essential element. Because calcium channel blockers cause arteriolar vasodilation and an increase in peripheral blood flow, they have been used to treat patients with Raynaud's phenomenon in several prospective, randomized, double-blind, placebo-controlled trials. Verapamil was ineffective in low doses, but both nifedipine and diltiazem produced subjective improvement. In placebo-controlled studies with nifedipine, the frequency of vasospastic episodes per two weeks decreased from 14.7 episodes during placebo therapy to 10.8 during nifedipine therapy (p less than 0.05). This response was more pronounced in patients without underlying vascular disease. Moderate or marked subjective improvement occurred in 60 percent of the patients receiving nifedipine and in only 13 percent of patients receiving placebo. Adverse effects were mild. It is concluded that nifedipine is an effective short-term therapy for most patients with Raynaud's phenomenon.

Calcium Channel Blockers↗
PubMed1985

Raynaud's phenomenon: pathophysiologic features and treatment with calcium-channel blockers.

Raynaud's phenomenon may be associated with severe pain, functional disability and digital infarction, particularly in patients with underlying vascular disease. The pathophysiologic features of Raynaud's phenomenon are complex although vasospasm contributes to the production of digital ischemia in most cases. Calcium-channel blockers have been shown to produce arteriolar vasodilation and an increase in peripheral blood flow. They have been used to treat patients with Raynaud's phenomenon in several prospective, randomized, double-blind, placebo-controlled trials. Low doses of verapamil were ineffective but both diltiazem and nifedipine produced subjective improvement in 60 to 90% of cases. Objective measures of digital blood flow were not improved. Patients without underlying vascular disease responded more readily to therapy than patients with scleroderma. Adverse effects were uncommon and seldom necessitated discontinuation of therapy. These data suggest that nifedipine and diltiazem provide effective short-term improvement in symptoms for most patients with Raynaud's phenomenon.

Calcium Channel Blockers↗
PubMed1985

Hemostatic effectiveness of fibrin glue derived from single-donor fresh frozen plasma.

Fibrin glue derived from pooled human blood is an effective sealant for high-porosity vascular grafts and a valuable topical hemostatic agent in heparinized patients. Use of this agent in the United States is prohibited because of potential transmission of hepatitis B, acquired immunodeficiency syndrome, and other serologically transmitted illnesses. We have developed a cryoprecipitation technique that allows preparation of fibrin glue from single-donor fresh frozen plasma. Use of this agent presumably entails no greater risk of disease transmission than intravenous administration of single-unit fresh frozen plasma. This report describes our early clinical experience with this material. Fibrin glue was used as a sealant for porous woven Dacron tubular prostheses and cardiovascular patches in 19 patients. The fibrin glue sealant has also been employed to control bleeding from needle holes and small anastomotic tears in 22 patients. No patient in this series had a bleeding complication from a suture line or graft treated with fibrin glue. This experience indicates that like fibrin glue from pooled blood, fibrin glue from single-donor plasma is effective as a graft sealant and topical hemostatic agent. Preparation of fibrin glue from single-donor plasma is simple and economical, and may provide cardiothoracic surgeons in the United States with a widely available, valuable hemostatic adjunct.

Blood Donors↗
PubMed1985

Cardiac transplantation. Changing patterns in evaluation and treatment.

This study reports the authors' experience with 66 heart transplants in 64 patients done over an 8-year period (1977-1985). In the early series, a high frequency of complications involving serious infections was noted. In April 1983, the immunosuppressive regimen was changed to cyclosporine and low-dose steroids. Patients were monitored with frequent myocardial biopsies and determinations of serum cyclosporine levels. Although this is not a controlled study, the authors believe that the improved results, including reduced frequency and severity of infections, are related to altered immune suppression. They speculate that patients with successful cardiac grafts develop a form of specific unresponsiveness and now are studying the mechanisms of this adaptation.

Azathioprine↗
PubMed1985

Serial alterations in the forms of immunoreactive pancreatic cationic trypsin in plasma from patients with acute pancreatitis.

We employed a radioimmunoassay for human cationic trypsin to define the time course for alterations in the molecular forms of this enzyme in plasma from patients with pancreatitis. Six patients developed acute pancreatitis as a complication of a known disorder [three, Reye's syndrome; two, hemolytic uremic syndrome (HUS); one, choledochal cyst]. The immunoreactive forms of cationic trypsin were determined by gel filtration of each plasma sample followed by radioimmunoassay of the column fractions. Early in the course of the disease, predominantly free trypsinogen was released into the circulation in five patients. In the three patients with Reye's syndrome, subsequent plasma samples showed, in addition to free trypsinogen, increasing amounts of immunoreactive trypsin complexed to alpha 2-macroglobulin and alpha 1-protease inhibitor. In contrast, subsequent samples from the two patients with HUS contained little or no inhibitor-bound trypsin. The remaining patient had intermediate concentrations of cationic trypsin complexed to these two circulating protease inhibitors. Five patients died and postmortem studies showed a striking correlation between the histological severity of acute pancreatic inflammation and the amount of immunoreactive trypsin complexed to alpha 2-macroglobulin and alpha 1-protease inhibitor. This preliminary study suggests that measurement of alpha 2-macroglobulin or alpha 1-protease inhibitor-bound trypsin may be a useful method of monitoring the progression and severity of disease in patients with acute pancreatitis. Characterization of serial changes in the forms of circulating pancreatic proteases may enhance our understanding of time-dependent pathophysiologic events, possibly leading to improved forms of specific therapy.

Acute Disease↗