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Biomedical subjects

A G Mulley

Publications and source records attributed to A G Mulley.

At least 37 records · Page 2Linked to original sources
PubMed1990

Quantitative serum toxic screening in the management of suspected drug overdose.

Data were collected on 176 consecutive cases of drug overdose evaluated in an emergency department. Quantitative serum toxic screening (TS) was performed for 164 (93%) of these patients; positive results were noted for 133 patients (81%). Six classes of drugs (ethanol, benzodiazepines, salicylates, acetaminophen, barbiturates, and tricyclic antidepressants) were responsible for nearly 70% of all drug detections and were associated with 80% of all admissions in this patient sample. Only two patients (1%) had drug-specific treatment initiated because of TS results. In 12 patients (7%), TS confirmed substances for which specific treatments had been initiated on clinical grounds. Four patients (2%) had drug-specific treatment discontinued because of TS results. Thirty-two patients (19%) were admitted to a medical service; however, only seven patients (4%) were admitted primarily because of TS results. All other patients were admitted because of clinical abnormalities that required inpatient care. It is concluded that only a few drugs are responsible for most drug overdoses. Moreover, TS results rarely change the treatment or disposition of overdose patients; these decisions are typically based on clinical parameters.

Acetaminophen↗
PubMed1990

Cost-effectiveness study of the extracorporeal shock-wave lithotriptor.

We performed a cost-effectiveness analysis to examine the relative efficacy and costs of percutaneous ultrasonic lithotripsy (PUL), extracorporeal shock-wave lithotripsy (ESWL), and surgery for the treatment of upper urinary tract stones. We developed a Markov model with 35 states, cycles of 3 months, and a time frame of 5 years. Probability estimates were derived from a meta-analysis of the published literature. For stones less than or equal to 2 cm, ESWL is preferred to PUL, since it prevents 2 additional days of morbidity and saves $440. For larger stones, PUL is preferable to ESWL, avoiding 4 days of morbidity, and saving $722. Both ESWL and PUL were superior to surgery. Sensitivity analysis showed that the results are sensitive to ESWL efficacy rates, the stone recurrence rate, and the hospital component of the ESWL cost. Our analysis suggests that although ESWL is preferable, relatively small changes in the efficacy and cost can shift the preferred strategy; in addition, these findings underscore the need for more reliable data.

Cost-Benefit Analysis↗
PubMed1989

Assessing patients' utilities. Can the ends justify the means?

Each of the elements of a utility assessment strategy--defining and describing health states of interest, identifying subjects, choosing a scaling task, aggregating across subjects, determining reliability and validity--is controversial. The controversy is in part explained by the interdisciplinary nature of the problem; different disciplinary conceptualizations of utility lead to different priorities for methodologic problem solving. Controversy is further explained by widely divergent potential applications of utility assessments, including individual decisions made with and without (or by) an agent, and decisions made for populations that may be homogeneous or heterogeneous with regard to utilities for the same health states. Issues can be clarified by focusing on the purpose of the utility assessment and, in the case of clinical decision making, on the most relevant disease-specific outcomes. The prostatectomy decision is an example. Although questions of measurement validity need continuing attention, more attention should be paid to validating uses of utility assessments: Can utility assessments distinguish prospectively, among patients who subsequently experience the same health outcome, those for whom it is associated with a high or low level of well-being? Can utility assessments be used to predict behavior? Can a decision process that includes utility assessments affect decisions in a manner that improves overall well-being? Approaches to such questions are complicated by changes in utilities over time, departures from the normative model of decision making, the effects of decision-making responsibility, and biases introduced by the decision-making process.

Attitude to Health↗
PubMed1988

Watchful waiting vs immediate transurethral resection for symptomatic prostatism. The importance of patients' preferences.

The rate of resection for benign prostatic hypertrophy shows considerable variability among small geographic areas. To help inform the decision to recommend prostatectomy to men with prostatism without signs of chronic retention, we performed a decision analysis to compare the expected outcomes with immediate transurethral resection and watchful waiting. Data used in the model originated from the medical literature, Medicare claims data, and patient interview studies. In our base-case analysis for 70-year-old men, immediate surgery resulted in the loss of 1.01 months of life expectancy, but when adjustments were made for quality of life, immediate surgery was favored with a net utility benefit of 2.94 quality-adjusted life-months. However, the analysis was particularly sensitive to the degree of disutility attributed to the index symptoms of prostatism. We conclude that patient preferences should be the dominant factor in the decision whether to recommend prostatectomy.

Age Factors↗
PubMed1988

Symptom status and quality of life following prostatectomy.

When prostatectomy is proposed as treatment for the symptoms of prostatism, the decision to operate should depend on how patients evaluate their symptoms and on objective information about the outcomes. We undertook a health interview study to determine the probabilities for symptom relief, improvement in the quality of life, and complications following surgery and to evaluate patient concern about the symptoms of prostatism. The operation was effective in reducing symptoms: 93% of severely and 79% of moderately symptomatic patients experienced improvement; however, a statistically significant improvement in indices of quality of life occurred only among patients with acute retention or severe symptoms prior to surgery. Short-term complications of varying severity occurred in 24% of patients; in addition, 4% reported persistent incontinence and 5%, impotence. Patients with similar symptoms reported considerable difference in the degree to which they were bothered by their symptoms. The result emphasizes the importance of patient participation in the decision to undergo prostatectomy.

Aged↗
PubMed1988

Management of nephrolithiasis: new approaches to "surgical" kidney stones.

The majority of kidney stones that come to clinical attention are large enough to cause symptoms but small enough to pass spontaneously. Recent technological developments have revolutionized the approach to kidney stones that heretofore required surgery. Percutaneous removal of stones through a nephrostomy tract, with or without ultrasonic or electrohydraulic lithotripsy, and extracorporeal shock wave lithotripsy (ESWL) have all but eliminated indications for open surgical procedures. These new techniques have their own advantages and are complementary. Despite these advances, any change in accepted indications for stone removal should await further evidence of the long-term safety of percutaneous techniques and ESWL.

Fluid Therapy↗
PubMed1988

Left ventricular ejection fraction. Physician estimates compared with gated blood pool scan measurements.

Gated blood pool scanning (GBPS) is an expensive, frequently used test to assess the left ventricular ejection fraction (LVEF). To determine whether a simpler method of evaluating LVEFs was reliable, we compared the LVEFs derived by GBPS with those estimated in a cardiologist's examination in 125 hospitalized patients. Of the physician estimates, 56% were accurate to within 7.5%, while 17% were underestimates and 27% were overestimates. The variables that were most predictive of reduced LVEF included cardiomegaly and pulmonary venous congestion on chest roentgenogram and S3 gallop, hypotension, and sustained left ventricular apex beat on examination. Prior hypertension was correlated with an increased LVEF. Variables associated with physician error in estimating the LVEF included a history of hypertension, bronchodilator therapy, and right bundle-branch block seen on the electrocardiogram. These data suggest that although qualitatively accurate estimates of the LVEF can sometimes be made on the basis of clinical findings, GBPS should be performed when management decisions hinge on a precise knowledge of this value.

Aged↗
PubMed1987

Dipyridamole-thallium scanning in patients undergoing vascular surgery. Optimizing preoperative evaluation of cardiac risk.

Dipyridamole-thallium imaging has been suggested as a method of preoperatively assessing cardiac risk in patients undergoing major surgery. To define more clearly its proper role in preoperative assessment, we prospectively evaluated 111 patients undergoing vascular surgery. In the first set of 61 patients, our data confirmed the value of preoperative dipyridamole-thallium scanning in identifying the patients who suffered postoperative ischemic events. Events occurred in eight of 18 patients with reversible defects on preoperative imaging, compared with no events in 43 patients with no thallium redistribution (confidence interval for the risk difference: 0.624, 0.256). The results also suggested that clinical factors might allow identification of a low-risk subset of patients. To test the hypothesis that patients with no evidence of congestive heart failure, angina, prior myocardial infarction, or diabetes do not require further preoperative testing, we evaluated an additional 50 patients having vascular procedures. None of the 23 without the clinical markers had untoward outcomes, while ten of 27 patients with one or more of these clinical markers suffered postoperative ischemic events (confidence interval for the risk difference: 0.592, 0.148). In the clinical high-risk subset, further risk stratification is achieved with dipyridamole-thallium scanning.

Aged↗
PubMed1987

Effect of workup strategy on the cost-effectiveness of fecal occult blood screening for colorectal cancer.

Physicians respond to a positive fecal occult blood test with a variety of workup strategies. To study the effect of the choice of strategy on the net costs and health benefits of colorectal cancer screening using this test, we used a decision analysis model to compare seven strategies that physicians might choose to examine a positive "screenee." Strategies using rigid or flexible sigmoidoscopy alone are not only insensitive, but also have high cost-effectiveness ratios. The strategy of air contrast barium enema alone had the lowest cost-effectiveness ratio. Rigid sigmoidoscopy combined with barium enema had a lower cost-effectiveness ratio than primary colonoscopy, but the strategy of primary colonoscopy could have an equal or better ratio depending on assumptions about test costs and the benefit of removing benign polyps. The primary colonoscopy strategy is both more effective and less costly than the combination of flexible sigmoidoscopy and barium enema. The optimal strategy will vary with local factors, and with the perspective of the decision-maker.

Aged↗
PubMed1986

Functional outcomes following medical intensive care.

This study describes the long-term functional outcomes of a medical and coronary care ICU population. Baseline and 1-yr follow-up data were collected prospectively from all 2213 patients admitted during a 2-yr period. Patients were stratified into three groups based on their preadmission functional status: active (n = 917), sedentary (n = 1017), or severely limited (n = 279). Those with severe functional limitation before admission were twice as likely to undergo major interventions (p less than .005). This group also had a significantly (p less than .001) higher mortality and incurred significantly (p less than .01) higher hospital charges than the other two groups, even though hospital lengths of stay were similar. Finally, cumulative mortality was significantly (p less than .001) greater for the severely limited patients: 33% expired in the ICU, 42% died while still in the hospital, and 63% died after discharge. Most survivors regained their preadmission functional status, with 60% of the previously employed returning to work. However, even for hospital survivors, mortality was high and was related to prior functional status: active 7%, sedentary 20%, severely impaired 37%.

Activities of Daily Living↗
PubMed1986

Age and the declining rate of autopsy.

To better understand declining autopsy rates, data have been gathered prospectively on 1080 consecutive deaths over six years among patients admitted to a medical intensive care/coronary care unit. Overall autopsy rate was 36%. Autopsy rates declined sharply with age from 60% for those aged 16 to 34 years to 23% for those 85 and over (P less than .001). The highest rates by diagnosis were aortic aneurysm (70%), hepatic failure (52%), heart rhythm disturbance (48%), pulmonary embolism (45%), and sepsis (41%). Patients receiving major procedures had a significantly higher autopsy rate (38 versus 29%, P less than .05) but rates bore little relation to prognoses given at admission by house officers, suddenness of death, sex, marital status or year of admission. Even among intensively treated patients, autopsy rates decline strikingly with age, demanding honest re-appraisal to restore the place of autopsy in medical education, clinical research, and quality of care assessment for an increasingly elderly population.

Adolescent↗
PubMed1986

Single-chamber and dual-chamber cardiac pacemakers. A formal cost comparison.

Dual-chamber pacemakers, more sophisticated and costly than single-chamber pacemakers, are being used with increasing frequency, often with unclear indications. Proponents of dual-chamber devices have focused on initial differences in cost without considering additional induced costs. We examined the incremental cost of dual-versus single-chamber pacemakers over the expected lifetime of a pacemaker recipient. In addition to initial costs, we included the costs of pacemaker malfunction, reimplantation, generator replacement, and follow-up. Expected differences in cumulative costs per patient were calculated over a 12-year period. Dual-chamber pacing is $2500 more costly at implantation. The difference in cumulative cost increases to $5100 by year 12, reflecting shorter functional life for dual-chamber pacemaker generators and increased cost of follow-up. The incremental cost of dual-chamber pacemaking is neither short-term nor trivial. Dual-chamber pacemakers should be reserved for those who clearly benefit from its advanced technology.

Costs and Cost Analysis↗
PubMed1986

Screening the healthy subject.

Screening tests may help or harm the healthy subject and, therefore, must be selected and used carefully. Criteria for selection include characteristics of the disease(s), of the potential screening tests, and of the population(s) to be screened. An understanding of methods used to evaluate tests will allow the investigator and the clinician to set realistic expectations for test performance in different clinical settings.

Anemia↗