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Biomedical subjects

R K Stuart

Publications and source records attributed to R K Stuart.

72 records · Page 4Linked to original sources
PubMed1971

Monitoring heparin therapy with the activated partial thromboplastin time.

Difficulties associated with the whole blood clotting time (W.B.C.T.) as a method of monitoring heparin therapy have led to the investigation of the activated partial thromboplastin time (A.P.T.T.) as an alternative. The conclusion is reached that the latter procedure possesses several advantages. Using the method described and a citrate-preserved blood sample collected just prior to the administration of the next serial dose of heparin, the suggested therapeutic duration of the A.P.T.T. is 70 seconds or twice the mean control value. A practical range for this method is 60 to 70 seconds.

Administration, Oral↗
PubMedDate not supplied

Parenteral trimethoprim-sulfamethoxazole and carbenicillin as empiric therapy for neutropenic patients with cancer.

A combination of parenteral trimethoprim-sulfamethoxazole and carbenicillin (TMP-SMZ-C) was compared with a gentamicin and carbenicillin combination (G-C) as empiric therapy for the febrile neutropenic patient with cancer in a prospective double-blind trial. Target plasma levels of TMP were achieved easily. When all trials were considered, TMP-SMZ-C was more effective (P less than or equal to 0.045) than G-C. When only proven infections were considered, the two regimens were equally effective. Adverse effects of both regimens were similar. Experience with infections due to individual organisms, particularly Pseudomonas aeruginosa and Staphylococcus aureus, was limited. General recommendations for use of TMP-SMZ-C in this patient population cannot be made until more comprehensive studies are done.

Agranulocytosis↗
PubMedDate not supplied

Electronic clinical trial protocol distribution via the World-Wide Web: a prototype for reducing costs and errors, improving accrual, and saving trees.

Clinical trials today typically are inefficient, paper-based operations. Poor community physician awareness of available trials and difficult referral mechanisms also contribute to poor accrual. The Physicians Research Network (PRN) web was developed for more efficient trial protocol distribution and eligibility inquiries. The Medical University of South Carolina's Hollings Cancer Center trials program and two community oncology practices served as a testbed. In 581 man-hours over 18 months, 147 protocols were loaded into PRN. The trials program eliminated all protocol hardcopies except the masters, reduced photocopier use 59%, and saved 1.0 full-time equivalents (FTE), but 1.0 FTE was needed to manage PRN. There were no known security breaches, downtime, or content-related problems. Therefore, PRN is a paperless, user-preferred, reliable, secure method for distributing protocols and reducing distribution errors and delays because only a single copy of each protocol is maintained. Furthermore, PRN is being extended to serve other aspects of trial operations.

Clinical Trials as Topic↗
PubMedDate not supplied

Energy requirements of parenterally fed bone marrow transplant recipients.

To determine the energy intake (kcal/kg/day) necessary to maintain zero nitrogen balance (assuming adequate protein intake) during the first 30 days after transplant, we studied 91 bone marrow transplant recipients. Serial nitrogen balance and concomitant energy and protein intakes were determined prospectively on each patient. Eight-four (92%) of the patients (ages 4-49 yr) had sufficient data for evaluation. For each patient, a simple linear model (nitrogen balance vs energy intake) was used to determine the patient's predicted individual energy requirement during the first 30 posttransplant days (EReq30). Weighted least squares multiple regression was used to determine the effect on EReq30 of such variables as age and sex. Energy requirements were significantly (p less than 0.001) greater for children, males, and patients with acute graft-vs-host disease, and when the percent of the total energy intake given by the intravenous route was high. An equation that incorporated these variables was developed to predict the energy requirements for bone marrow transplant recipients during their first 30 posttransplant days. Although individual energy requirements vary, this equation is a useful guide for initial energy prescriptions.

Adolescent↗
PubMedDate not supplied

Incidence of arrhythmia with central venous catheter insertion and exchange.

The risk of complication during the insertion or exchange of central venous catheters has been well documented. The majority of complications involve mechanical problems associated with insertion. Although cardiac arrhythmia has been acknowledged as a possible complication, its incidence has never been quantified. We performed cardiac monitoring on patients during 51 central venous catheter insertions or exchanges to determine the incidence of cardiac arrhythmias during guidewire insertion. Forty-one percent of procedures resulted in atrial arrhythmias and 25% produced some degree of ventricular ectopy, 30% of these were ventricular couplets or greater. Ventricular ectopy was significantly more common in shorter patients (160 +/- 8 vs 168 +/- 11 cm, p less than 0.05) and when the catheter was inserted from the right subclavian position (43% ventricular ectopy vs 10% at the other sites). Other variables such as age, cardiac history, serum potassium, type of procedure, and catheter brand were not significant. It is our conclusion that over-insertion of the wire causes this cardiac stimulation. Despite the absence of morbidity or mortality in this study, this incidence of ventricular ectopy indicates that there is a distinct possibility of a malignant arrhythmia being precipitated by a guidewire. Some modification of the current protocol for these procedures seems indicated.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Reducing arrhythmias associated with central venous catheter insertion or exchange.

A recent study demonstrated that the incidence of new arrhythmias occurring during central venous catheter insertion or exchange was 41% atrial and 25% ventricular arrhythmias (12% couplets or greater). Over-insertion of the guidewire, causing direct stimulation to the right side of the heart, has been postulated to be the causative factor. A new technique that allows the operator to control the length of guidewire inserted was developed. With this technique on a population of hospitalized patients, similar to those in the previous study, the incidence of atrial arrhythmias decreased to 32% and the incidence of ventricular arrhythmias to 6% (single premature ventricular contractions only). Although this new technique has limitations, there was a dramatic improvement in the incidence of cardiac arrhythmias. These results indicate a need for modifications in the available equipment to avoid the infrequent but life-threatening complication of malignant arrhythmia.

Arrhythmias, Cardiac↗