Cardiac output assessment methods in left ventricular assist device patients: A problem of heteroscedasticity.

Equipoise remains about how best to measure cardiac output (CO) in patients with left ventricular assist devices (LVAD). In this study, direct Fick CO was compared with thermodilution (TD) and indirect Fick (iFick) CO in 61 LVAD patients. TD and LaFarge iFick showed moderate correlation with direct Fick (R2 = 0.49 and R2 = 0.38, p < 0.001 for both), while Dehmer and Bergstra iFick showed poor correlation with direct Fick (R2 = 0.29 and R2 = 0.31, p < 0.001 for both). Absolute bias between all CO estimation techniques and direct Fick CO was lowest for TD compared to iFick methods but significant for all methods. All methods tended to overestimate CO compared to direct Fick, with greatest overestimation present in those with the lowest measured direct Fick CO. Bias and frequency of significant discrepancy were least using TD and Lafarge iFick CO estimation methods in this study, with TD CO demonstrating modestly better correlation and less heteroscedasticity compared to Lafarge.

US residency training before and after the 1997 Balanced Budget Act.

CONTEXT: Graduate medical education (GME) determines the size and characteristics of the future workforce. The 1997 Balanced Budget Act (BBA) limited Medicare funding for additional trainees in GME. There has been concern that because Medicare is the primary source of GME funding, the BBA would discourage growth in GME. OBJECTIVE: To examine the number of residents in training before and after the BBA, as well as more recent changes in GME by specialty, sex, and type and location of education. DESIGN: Descriptive study using the American Medical Association/Association of American Medical Colleges National GME Census on physicians in Accreditation Council for Graduate Medical Education (ACGME)-accredited programs to examine changes in the number and characteristics of residents before and after the BBA. MAIN OUTCOME MEASURES: Differences in the number of physicians in ACGME-accredited training programs overall, by specialty, and by location and type of education. RESULTS: The number of residents and fellows changed little between academic year (AY) 1997 (n = 98,143) and AY 2002 (n = 98,258) but increased to 106,012 in AY 2007, a net increase of 7869 (8.0%) over the decade. The annual number of new entrants into GME increased by 7.6%, primarily because of increasing international medical graduates (IMGs). United States medical school graduates (MDs) comprised 44.0% of the overall growth from 2002 to 2007, followed by IMGs (39.2%) and osteopathic school graduates (18.8%). United States MD growth largely resulted from selection of specialties with longer training periods. From 2002 to 2007, US MDs training in primary care specialties decreased by 2641, while IMGs increased by 3286. However, increasing subspecialization rates led to fewer physicians entering generalist careers. CONCLUSION: After the 1997 BBA, there appears to have been a temporary halt in the growth of physicians training in ACGME programs; however, the number increased from 2002 to 2007.

A short-duration dark adaptation protocol for assessment of age-related maculopathy.

Dark adaptometry may be a useful diagnostic test and clinical trial endpoint for age-related maculopathy (ARM) because impaired night vision is a hallmark of early ARM. A novel dark adaptometer, the AdaptDx, was evaluated for the detection of ARM. The AdaptDx incorporates a 20-minute protocol optimized for the detection of ARM. ARM patients (N = 17) exhibited substantial dark adaptation impairment compared with normal adults (N = 17). The diagnostic sensitivity was 88% and the specificity was 100%. The diagnostic test characteristics of the AdaptDx are similar to previously reported studies using 60- to 120-minute protocols.