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Biomedical subjects

C D Hepler

Publications and source records attributed to C D Hepler.

At least 37 records · Page 2Linked to original sources
PubMed1986

Controversies in antimicrobial therapy: critical analysis of clinical trials.

Problems with design and statistical evaluation of clinical efficacy trials of antimicrobial agents are reviewed. Of the three major criteria used for evaluating antimicrobial agents (efficacy, toxicity, cost), the most important is efficacy. Clinical efficacy can be evaluated in uncontrolled or controlled clinical trials. Uncontrolled trials are often conducted to satisfy Food and Drug Administration requirements during premarketing testing; the response rate is typically high because only patients with susceptible infections may be treated and large doses are given. Controlled antibiotic trials should be randomized, blinded, parallel comparisons of an investigational agent versus the best available agent at an accepted dose. However, interpretation of these studies is frequently clouded by poor study design, small sample sizes, and heterogeneous patient populations. Controlled trials are usually centered around a null hypothesis (i.e., that no difference will be found between the agents being compared). All conclusions (to reject or not reject the null hypothesis) should be carefully evaluated by clinicians seeking to apply the available data to patient care. Researchers can incorrectly conclude that two therapies have equal efficacy because of insufficient statistical power (i.e., small sample size) or poor study design. Likewise, researchers may incorrectly conclude that there is a statistical difference between two therapies because of poor design or improper sample selection. For the clinician, clinical relevance takes precedence over statistical significance. Before the results of a study are allowed to affect drug use in an institution, strong similarities between subjects and methods in the study and patients and care in the institution should be demonstrated.

Anti-Bacterial Agents↗
PubMed1985

Drug choice as a problem-solving process.

A model of the drug prescribing process, which incorporates prescribers' personal values about treatment outcomes and beliefs about treatment effects, was tested under actual clinical conditions. Forty physicians were given two fictional case histories and six disguised case histories of patients whom they had recently treated for hypertension or maturity-onset diabetes mellitus. The physicians completed questionnaires based on each case history that measured 1) the beliefs about the probability that seven treatment-related outcomes would result from the prescribing of several alternative treatments and 2) the values placed on each outcome. The physicians were also asked, in an open-ended question, how they would treat the patient described in the case. The 40 physicians proposed 172 drug treatments that corresponded to treatment alternatives for which beliefs about treatment effects had been measured. The model correctly predicted 1) prescribing intent in 81% of hypertension cases and in 87% of the diabetes cases and 2) actual prescribing in 76% of hypertension cases and in 70% of the diabetes cases, significantly more than would be expected at random (P less than 0.01). The prescribing model appears useful for predicting drug choices for the outpatient treatment of hypertension and diabetes by resident physicians.

Attitude of Health Personnel↗
PubMed1985

Improving patient-oriented pharmacy services: panel discussion.

A panel discussed ways to improve patient-oriented pharmacy services, drawing on the proceedings of a recent conference on directions for clinical practice in pharmacy. Clinical pharmacy should be defined in terms of responsibility rather than by a list of specific functions. Pharmacists are responsible for drug use, not just for dispensing; this implies responsibility for educating physicians and nurses to ensure optimal patient outcomes. Clinical practice cannot be separated from pharmacy practice; although pharmacy practice requires different kinds of tasks, all have the goal of patient care. Pharmacists can exercise their responsibility for control of drug use without prescriptive authority or mandated review of physician prescribing. Pharmacists can increase their influence on drug therapy through the formulary system and through their physical presence on patient-care units. A mission statement that recognizes responsibility for patient outcomes can serve as the basis for a management system that supports clinical practice. The panel members believed that pharmacy leaders at the conference were unified by a commitment to increase the profession's clinical orientation.

Humans↗
PubMed1984

Effect of an automated bedside dispensing machine on medication errors.

The effect of an automated bedside dispensing machine on medication errors was studied on a 32-bed surgical unit of an 848-bed hospital. The experimental system (McLaughlin Dispensing System) included at each patient's bedside a locked medication cabinet that was electronically programmed to allow the nurse access to doses due at a particular time. The control system was a decentralized unit dose system. A crossover study design with random assignment of subjects and treatments was used. In the 14-day study period, nurses were observed by a pharmacist for 28 five-hour periods as they administered medications on the day and evening shifts. The mean error rates were significantly different--10.6% for the experimental system and 15.9% for the control system. Wrong time errors were the most common type. No significant differences were found between day and evening shifts or workloads of individual nurses. There was no treatment order effect. The error rate was significantly lower for the automated dispensing system than for the system using unit doses dispensed from a satellite pharmacy. Automated dispensing systems may be useful in reducing errors in administration time and dose omissions.

Computers↗
PubMed1982

Antibiotic use review in ambulatory care using computer-assisted medical record audit.

The use of a computer-assisted medical record audit (CAMRA) for reviewing antibiotic use in ambulatory patients was evaluated. A random sample of 40 medical records documenting treatment of streptococcal pharyngitis, otitis media, or acute, uncomplicated urinary tract infections at two family practice clinics was used to evaluate the accuracy and efficiency of computerized prescription screening and CAMRA relative to medical record audit (MRA) alone. Accuracy was the ability to correctly classify antibiotic therapy as appropriate or inappropriate. The initial computerized prescription screening criteria were modified to reduce the proportion of false positives and negatives and a second random sample of 40 medical records was audited. The computerized prescription screening was the most efficient method, requiring less than one hour of professional time to audit 80 medical records. MRA and CAMRA took 17.4 and 3.0 hours, respectively. By definition, MRA was 100% accurate. Computerized prescription screening and CAMRA correctly classified 73% and 78% of the medical records, respectively. The results of this study are similar to a previous study reviewing antihypertensive therapy, but this study showed CAMRA less favorably. This is primarily because of the many diagnoses for which a particular antibiotic can be prescribed and the wide dosage ranges for antibiotics based on body weight. CAMRA could be more useful for evaluating antibiotic therapy if diagnostic information were available before doing the computerized prescription screening and if the computerized prescription screening criteria included patient diagnosis and body weight.

Ambulatory Care↗
PubMed1982

Prescribers' beliefs and values as predictors of drug choices.

A cognitive model of the drug-prescribing process, which incorporates prescribers' attitudes (valences) about treatment outcomes and beliefs (instrumentalities) about drug effects, was tested. Twelve physicians were interviewed to identify common outcomes associated with drug therapy; six distinct outcomes were identified. Then 50 family practice residents were given a hypothetical description of a mildly hypertensive patient and three treatment choices. The physicians completed a questionnaire that identified (1) the instrumentalities of each of the alternative treatments for each of the six outcomes and (2) the valences for each outcome. The physicians were also asked to respond to an open-ended question on how they would treat the patient described in the case. Forty-six physicians proposed 39 treatments that corresponded to the three treatments for which instrumentalities and valences were available. The drug-choice model correctly predicted 28 of 39 (72%) therapeutic decisions, which was significantly more than would be expected by chance (p less than 0.01). Both valences and instrumentalities appear important for predicting prescribing intention. Pharmacists can use this model in their attempts to influence prescribing.

Attitude of Health Personnel↗
PubMed1981

Clinical trial of topical erythromycin in inflammatory acne.

Sixty-nine informed subjects participated in a split-face, double-blind trial of topical erythromycin base 2% in Vehicle/N versus Vehicle/N alone. All subjects had grades II or III acne as described by Pillsbury. Study solutions were assigned to a randomly selected side of the subject's face. Solutions were applied twice daily. Inflammatory lesion counts were performed by the same investigator during the eight weeks of study at biweekly intervals. The difference in inflammatory lesion counts from beginning to end of study for each side of the face was compared utilizing Student's paired t-test. There was not a statistically significant difference in mean inflammatory lesions at the end of eight weeks (D = 1.46, t = 1.36, df 68). There was, however, a significant difference at two and six weeks (D = 2.59, t = 3.72, df 68; D = 1.41, t = 2.03, df 68). Observed differences in lesion counts were not considered to be clinically significant.

Acne Vulgaris↗
PubMed1981

Comparative trial of two sulfisoxazole regimens in acute urinary tract infection.

Many clinicians are utilizing a 2-g loading dose of sulfisoxazole in the treatment of uncomplicated urinary tract infection. Although some of these clinicians understand the theoretical reasons for not utilizing such a treatment plan, they may be reluctant to depart from the official recommendations for sulfisoxazole because of the lack of supporting clinical data. The findings of this study provide support for the theoretical considerations outlined previously. Also, considering the potential disadvantages of the loading dose employment, for example, source of patient misunderstanding and complicated patient instructions data supporting the omission of a sulfisoxazole loading dose should be most welcome. In conclusion, the study results suggest that the inclusion of a 2-g loading dose of sulfisoxazole in the treatment of this sample of acute, uncomplicated urinary tract infections did not offer any therapeutic benefit.

Acute Disease↗
PubMed1980

Factors associated with creatinine clearance changes following gentamicin therapy.

The relationship between creatinine clearance changes during gentamicin therapy and several patient and therapeutic variables was studied in a prospective, multicenter trial. Adult patients in three hospitals who were receiving gentamicin in doses based on lean body weight and creatinine clearance were studied. Pre- and post-therapy serum creatinine measurements were obtained for 62 patients (Group 1); only 45 of the patients had both pre- and post-therapy creatinine clearance measurements (Group 2). Other data collected for correlation with creatinine clearance changes were: body temperature, age, sex, blood pressure, albumin level, previous and concomitant therapy with nephrotoxic drugs, hematocrit, peak and trough gentamicin levels, and duration of therapy. In Group 2 patients, only peak gentamicin level, concomitant therapy, sex, and previous furosemide therapy correlated significantly (p less than or equal to 0.05) with change in creatinine clearance during gentamicin therapy. The first two variables decreased creatinine clearance, the last variable increased creatinine clearance, and women tended to have more of a decrease in clearance than did men. Sex, peak gentamicin level, prior furosemide therapy and concomitant cephalothin therapy explain about 50% of the renal function changes during gentamicin therapy, and should be considered in monitoring gentamicin therapy.

Analysis of Variance↗
PubMed1980

Problems and hypotheses.

The formulation and relationship of precisely defined research questions and hypotheses and their importance in the research process are discussed. A hypothesis is defined as a linkage of two or more abstract variables, each of which is derived from the observational level. The successive abstractions of the derivation process, the characteristics of the variables so derived, and the relationship of both to study design and measurement are defined and discussed.

Abstracting and Indexing↗
PubMed1980

Use of simulation to develop multiple-dose regimens for drugs exhibiting nonlinear elimination kinetics.

A mathematical model and resulting computer program for simulating blood-level versus time profiles of drugs exhibiting saturable elimination processes are described and evaluated. The iterative digital-analog simulator (IDAS) program consists of two sections--a simulation (SIM) module and an iteration control (IC) module. The SIM module predicts minimum and maximum serum drug levels based on a dose and a dosing interval. The IC module takes the minimum and maximum serum levels from the SIM module and produces a new dose (for a new maximum serum level) and a new dosing interval (for a new minimum serum level). The new dosing information is fed back into the SIM module and the iteration process is repeated until the predicted minimum and maximum levels converge on desired levels set by the user of the program. The model and program were tested by comparing simulation results with actual patient data for phenytoin (seven patients) and theophylline (three patients). The ability of the program to converge on correct doses and dosing intervals was evaluated under a variety of given conditions. The mean difference between actual and simulated profiles was 0.286 mg/liter and 1.5 mg/liter for phenytoin and theophylline, respectively. IDAS produced dose and dosing interval estimates within desired precision given a variety of initial input data. The results encourage prospective clinical investigation of the reliability and validity of the method.

Computers, Hybrid↗