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Charles McCulloch

Publications and source records attributed to Charles McCulloch.

8 recordsLinked to original sources
PubMed2007

House staff team workload and organization effects on patient outcomes in an academic general internal medicine inpatient service.

BACKGROUND: House staff work-hour regulations have required residency programs to reengineer inpatient services. However, few data describe how house staff workload on a patient's day of admission or on subsequent hospital days influences patient outcomes. METHODS: Retrospective cohort analysis of 5742 adults admitted to an academic general medical service between July 1, 1998, and June 30, 2001. RESULTS: After multivariate risk adjustment for patient severity and other structural factors, we found that 2 different measures of house staff workload significantly affected patient outcomes. House staff workload increases on the day of admission, defined as each additional team admission on a patient's admission day, increased length of stay (difference, 3.09%; 95% confidence interval [CI], 2.22%-3.96%), total costs (difference, 2.31%; 95% CI, 1.29%-3.33%), and risk of inpatient mortality (odds ratio, 1.09; 95% CI, 1.02-1.15). Patients had an even higher mortality risk when more than 9 patients were admitted to their team on their admission day. In contrast, house staff workload increases during the patient's entire stay, defined as every additional patient added to the team average census, reduced length of stay (difference, -5.30%; 95% CI, -4.54% to -6.07%) and total costs (difference, -5.11%; 95% CI, -4.20% to -6.00%). Reductions in length of stay and costs were most striking when the team average census exceeded 15 patients. CONCLUSIONS: Our findings suggest that higher house staff workload on admitting days-when fewer backup resources are available-increases resource use and may increase inpatient mortality. Conversely, a higher average team census was associated with reduced resource use, perhaps reflecting service-level adaptations to workload. Future studies should confirm these findings in larger trials.

Aged↗
PubMed2006

Inactivation of prions by acidic sodium dodecyl sulfate.

Prompted by the discovery that prions become protease-sensitive after exposure to branched polyamine dendrimers in acetic acid (AcOH) (S. Supattapone, H. Wille, L. Uyechi, J. Safar, P. Tremblay, F. C. Szoka, F. E. Cohen, S. B. Prusiner, and M. R. Scott, J. Virol. 75:3453-3461, 2001), we investigated the inactivation of prions by sodium dodecyl sulfate (SDS) in weak acid. As judged by sensitivity to proteolytic digestion, the disease-causing prion protein (PrPSc) was denatured at room temperature by SDS at pH values of < or =4.5 or > or =10. Exposure of Sc237 prions in Syrian hamster brain homogenates to 1% SDS and 0.5% AcOH at room temperature resulted in a reduction of prion titer by a factor of ca. 10(7); however, all of the bioassay hamsters eventually developed prion disease. When various concentrations of SDS and AcOH were tested, the duration and temperature of exposure acted synergistically to inactivate both hamster Sc237 prions and human sporadic Creutzfeldt-Jakob disease (sCJD) prions. The inactivation of prions in brain homogenates and those bound to stainless steel wires was evaluated by using bioassays in transgenic mice. sCJD prions were more than 100,000 times more resistant to inactivation than Sc237 prions, demonstrating that inactivation procedures validated on rodent prions cannot be extrapolated to inactivation of human prions. Some procedures that significantly reduced prion titers in brain homogenates had a limited effect on prions bound to the surface of stainless steel wires. Using acidic SDS combined with autoclaving for 15 min, human sCJD prions bound to stainless steel wires were eliminated. Our findings form the basis for a noncorrosive system that is suitable for inactivating prions on surgical instruments, as well as on other medical and dental equipment.

Animals↗
PubMed2005

Quality of care and its impact on population health: a cross-sectional study from Macedonia.

Research has revealed significant variation in both the quality of clinical care and the health status of populations. We conducted a study to determine if variations in the quality of clinical care can be quantitatively linked to variations in health status, at the patient and the population level. This study, conducted at health facilities in four municipalities in Macedonia, collected cross-sectional data on (1) structural measures (such as infrastructure, facilities, equipment and costs) and the quality of clinical care provided by physicians (as measured by clinical vignettes); (2) detailed health and socioeconomic status information on patients using the facilities; and (3) nearly the same information on a random sample of adults in each municipality. Data were collected from a total of 57 facilities, 273 physicians, 1451 patients, and 1627 adults from the general population. The main outcome measure was health status, based on self-reported health surveys. Objective health measures were obtained to control for preexisting conditions. The main explanatory variable was quality of clinical care, based on physicians' clinical vignette scores. Structural measures were included in our model but had a more distal relationship to health status. We found that quality of care strongly predicted self-reported health status of patients using the facilities even after controlling for other factors (p < .05). Quality of care was also associated with higher health status for the population living in the surrounding community, regardless of utilization (p < .05). This linkage between quality of clinical care and health suggests that policies that improve clinical practice have the potential to improve population health more rapidly than other interventions.

Adult↗
PubMed2004

What does my patient's coronary artery calcium score mean? Combining information from the coronary artery calcium score with information from conventional risk factors to estimate coronary heart disease risk.

BACKGROUND: The coronary artery calcium (CAC) score is an independent predictor of coronary heart disease. We sought to combine information from the CAC score with information from conventional cardiac risk factors to produce post-test risk estimates, and to determine whether the score may add clinically useful information. METHODS: We measured the independent cross-sectional associations between conventional cardiac risk factors and the CAC score among asymptomatic persons referred for non-contrast electron beam computed tomography. Using the resulting multivariable models and published CAC score-specific relative risk estimates, we estimated post-test coronary heart disease risk in a number of different scenarios. RESULTS: Among 9341 asymptomatic study participants (age 35-88 years, 40% female), we found that conventional coronary heart disease risk factors including age, male sex, self-reported hypertension, diabetes and high cholesterol were independent predictors of the CAC score, and we used the resulting multivariable models for predicting post-test risk in a variety of scenarios. Our models predicted, for example, that a 60-year-old non-smoking non-diabetic women with hypertension and high cholesterol would have a 47% chance of having a CAC score of zero, reducing her 10-year risk estimate from 15% (per Framingham) to 6-9%; if her score were over 100, however (a 17% chance), her risk estimate would be markedly higher (25-51% in 10 years). In low risk scenarios, the CAC score is very likely to be zero or low, and unlikely to change management. CONCLUSION: Combining information from the CAC score with information from conventional risk factors can change assessment of coronary heart disease risk to an extent that may be clinically important, especially when the pre-test 10-year risk estimate is intermediate. The attached spreadsheet makes these calculations easy.

Adult↗
PubMed2004

Back to the future: Smoking in movies in 2002 compared with 1950 levels.

We reviewed smoking shown in a random sample of major motion pictures from 1950 through 2002. Smoking incidents declined from 10.7 incidents per hour in 1950 to a minimum of 4.9 in 1980-1982 but increased to 10.9 in 2002. Despite declining tobacco use and increasing public understanding of the dangers of smoking in the real world, smoking in movies has returned to levels observed in 1950, when smoking was nearly twice as prevalent in reality as it was in 2002.

Adolescent↗
PubMed2003

Isolated bundle branch block and left ventricular dysfunction.

BACKGROUND: Population studies have identified the presence of bundle branch block (BBB) as a risk factor for increased mortality in patients with known cardiac disease. It is unknown how chronic ventricular dyssynchrony resulting solely from conduction delay affects ventricular function. METHODS AND RESULTS: Subjects were retrospectively identified from the University of California, San Francisco, electrocardiogram database with QRS prolongation. Subjects who had no evidence of heart disease and had baseline and serial studies evaluating ongoing risk of coronary artery disease status and left ventricular function were followed over time. Documentation of a minimum of 2 serial evaluations of cardiac status were present in a total of 51/176 (20%) subjects with isolated BBB who constitute the study population. After a mean follow-up of 52 +/- 45 months-adjusting for differences due to age, sex, the presence of hypertension, hyperlipidemia, and diabetes mellitus-left ventricular ejection fraction diminished by -7.3 +/- 12% per year in the isolated left BBB cohort versus -1.9 +/- 4% in isolated right BBB cohort and -1.1 +/- 3% reduction in the isolated nonspecific intraventricular conduction delay cohort (P =.019). CONCLUSIONS: Left bundle branch block itself may be a cause of ventricular dysfunction.

Aged↗