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Biomedical subjects

J W Vance

Publications and source records attributed to J W Vance.

At least 19 recordsLinked to original sources
PubMed1995

Noncardiac pulmonary edema, newer environmental aspects. An update.

Accidental spread of potentially toxic gases, fumes, and particulate chemicals has been reported recently in various cities throughout the country and appears to be on the increase throughout the world in the past few years. Moreover, cerebral trauma, septic shock (ARDS), and environmental pulmonary edema from drug intoxication have been commonly encountered. Newer modalities of treatment include selective [corrected] fiber optic bronchoscopy, constant positive airway pressure mask, administration of surfactant, pentoxifylline, and use of newer experimental agents such as nitrous oxide, antitumor necrosis factor (ATNF), and extracorporeal carbon dioxide with low-frequency positive pressure (ECCO2R-LFPPV). The future holds promise for probable reductions in both morbidity and mortality rates of this ubiquitous occupational and environmental health problem, which is of global importance.

Accidents, Occupational↗
PubMed1987

Dual individualization of intravenous ciprofloxacin in patients with nosocomial lower respiratory tract infections.

Dual individualization is the integration of patient-specific pharmacokinetic parameters with the pharmacodynamics (concentration versus response) of the infecting pathogen. This technique allows description of the time of in vivo bacterial eradication, and allows estimation of optimal dosages using small numbers of seriously ill patients. In an ongoing study, 11 patients with nosocomial lower respiratory tract infections were given 200 mg of intravenous ciprofloxacin every 12 hours. Ten blood samples were taken after the first dose, with additional peaks and troughs measured on Day 4 and at the end of treatment. Bacterial isolates had minimal inhibitory concentrations (MICs) determined by standard microdilution techniques. In the 11 patients, there were 14 bacterial isolates, of which seven were Pseudomonas aeruginosa and the remainder were other pathogens. Ciprofloxacin MICs ranged from 0.008 to 1.0 microgram/ml. The pharmacokinetics of ciprofloxacin in these patients varied with renal function, and average peak serum concentrations ranged from 1.7 to 4.9 micrograms/ml. Eradication of bacteria from tracheal aspirates occurred between Days 1 and 7, except in four patients in whom the organism persisted. Correlations were observed between the day of eradication and the length of time ciprofloxacin concentrations remained above the minimal inhibitory concentration (MIC). Essentially all bacteria with MICs of less than 0.25 were eradicated. Of the non-eradicated bacteria, most had either MICs of more than 0.25, or less than 100 percent time above the MIC. The clinical response was satisfactory. It is concluded that 200 mg of intravenous ciprofloxacin every 12 hours is highly effective for bacteria with MICs less than 0.25 microgram/ml, but higher dosages may be required to eradicate organisms with higher MICs.

Aged↗
PubMed1984

Role for dual individualization with cefmenoxime.

Cefmenoxime concentration/effect relationships were retrospectively explored for gram-negative bacteria isolated from 14 critical care patients treated for nosocomial pneumonia. The effects of cefmenoxime concentrations on in vitro growth kinetics of 21 isolated pathogens were studied using the Abbott MS-2 Research System, from which a dynamic response concentration was derived. Serum pharmacokinetic profiles were obtained in each patient. These data were used to calculate the in vivo total area under the curve over dynamic response concentration and the time that cefmenoxime concentrations exceeded the dynamic response concentration for each bacteria. The same determinations were made in 18 patients prospectively treated, except that dosage was optimized on the basis of previous mathematical relations to achieve bacterial eradication in four days. This method of dosage optimization is termed dual individualization. Serial cultures of infected tissues were evaluated to determine the number of days to the eradication of bacteria, and the pharmacokinetic and pharmacodynamic variables were used to describe the bacteriologic response of the original pathogen isolated in pretreatment culture. Bacterial eradication rates could be described from cefmenoxime pharmacokinetics in the patient and from the relation between concentration and bacterial inhibition. Patients who were prospectively treated using these retrospectively derived relationships had a predictable day of bacterial eradication. This, in turn, was associated with a shorter duration of treatment (p less than 0.05). The success of prospective dual individualization is encouraging and suggests that more precise optimization of antibiotic dosage can yield a predictable rate of bacterial eradication from the infection site.

Aged↗
PubMed1977

Tissue persistence of gentamicin in man.

A two-compartment pharmcokinetic model was used to caracterize serum concentrations and to predict tissue accumulation of gentamicin in 47 treated patients. Postmortem tissues were obtained in six cases; in each instance, tissues yielded the predicted amount of drug. Slow release of tissue-bound gentamicin accounts for its prolonged retention in the body. The two-compartment model adequately predicts gentamicin accumulation from serum concentrations and explains why this antibiotic persists in serum and urine.

Adult↗
PubMed1977

Intravenous theophylline therapy: nomogram guidelines.

We evolved a nomogram for guiding and standardizing intravenous theophylline therapy in hospitalized patients. It provides rapid calculation of a loading dose based on body weight and previous therapy and a maintenance infusion rate related to three categories of expected metabolic activity. The guidelines were prospectively used in the treatment of 72 patients, mainly in a respiratory care unit. The nomogram was successfully used to attain near-steady-state serum concentrations in the therapeutic range of 8 to 20 mg/litre in 72% of patients, with only two patients outside of the range of 5 to 25 mg/litre. These guidelines facilitate initial theophylline dosage in older patients with liver and cardiac disease and provide a rational basis for interpreting serum concentration measurements and adjustment of drug therapy.

Adult↗
PubMed1976

System for clinical pharmacokinetic monitoring of theophylline therapy.

A system was developed for guiding theophylline therapy in acutely ill patients with respiratory disease and for recovery of pharmacokinetic information. A dosage regimen nomogram was designed based on literature data and preliminary pharmacokinetic studies in patients. Using the nomogram, physicians select the loading and infusion dosages based on previous therapy, body weight, age, and cardiac and hepatic status of the patient. Specifications are provided for loading (up to 5.6 mg/kg) and maintenance doses (0.9, 0.68, or 0.45 mg/kg/hr) of aminophylline, handling of i.v. dosage forms, and collection of three initial blood samples. Serum samples were assayed for theophylline by high-performance liquid chromatography for rapid feedback of data to the physician and computer estimation of body clearance values. The usefulness of the nomogram guidelines was examined prospectively in 72 patients. Near-steady-state serum concentrations in the therapeutic range of 8-20 mg/liter were found in 72% of the patients. Only two patients were outside of the range of 5-25 mg/liter. The relationship between the physician's estimate of the patient's clinical status (three classes) and measured body clearance was highly significant (p less than 0.025). A comprehensive data collection format allows further analysis of the factors responsible for the variability in theophylline disposition in patients undergoing therapy.

Adult↗