PubMed Health⌕ Search

Biomedical subjects

T Speroff

Publications and source records attributed to T Speroff.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Lens model analysis of hemodynamic status in the critically ill.

The lens model recently has been extended to consider multiple outcomes and sequential use of clinical information. The authors have used this extended model 1) to describe the relationship between clinical information and physicians' assessments of hemodynamic status, 2) to describe the empirical relationship between clinical information and physiologic measures of hemodynamic status, and 3) to compare physicians' use of information with its empirical utility. Physicians prospectively provided estimates of cardiac index and pulmonary capillary wedge pressure for 440 intensive care unit patients prior to right heart catheterization. The correlation between physicians' estimates and measured hemodynamic status was lower than that between clinical information and hemodynamic status (0.42 versus 0.67). Only 7% of physicians' judgement was related to subsequent ancillary testing. Empirically, subsequent ancillary testing contributed 30% to the explanation of hemodynamic status. The lens model describes limitations of physician judgement in estimating left ventricular function and helps explain how patient features relate to measured hemodynamic status.

Cardiac Catheterization↗
PubMedDate not supplied

Hemodynamic assessment in managing the critically ill: is physician confidence warranted?

Prior to right-heart catheterization of 846 patients, 198 study physicians estimated values of pulmonary capillary wedge pressure (WP), cardiac index (Cl), and systemic vascular resistance index (VRI). The physicians also expressed their confidence in these estimates. Actual values of WP, Cl, and VRI as determined by catheterization enabled the authors to evaluate the quality of the physicians' judgments. The discrimination of the judgments was modest; areas under the ROC curves for WP, Cl, and VRI were 0.724, 0.681, and 0.656, respectively. Calculated using clinically relevant cutoff values, sensitivities were 64%, 50%, and 64%, and specificities were 71%, 75%, and 63%, respectively. Calibration of the estimates of WP, Cl, and VRI was also modest; physicians tended to overestimate low values and underestimate high values. Physicians were generally confident of their estimates, but there was no relation between confidence and accuracy. Experienced physicians were no more accurate than less experienced ones, although they were significantly more confident. The authors conclude that physicians should not use their levels of confidence in their subjective estimates of cardiac function in deciding whether to base therapy on these estimates.

Cardiac Catheterization↗
PubMedDate not supplied

The covariance decomposition of the probability score and its use in evaluating prognostic estimates. SUPPORT Investigators.

The probability score (PS) or Brier score has been used in a large number of studies in which physician judgment performance was assessed. However, the covariance decomposition of the PS has not previously been used to evaluate medical judgment. The authors introduce the technique and demonstrate it by analyzing prognostic estimates of three groups: physicians, their patients, and the patients' decision-making surrogates. The major components of the covariance decomposition--bias, slope, and scatter--are displayed in covariance graphs for each of the three groups. The decomposition reveals that whereas the physicians have the best overall estimation performance, their bias and their scatter are not always superior to those of the other two groups. This is primarily due to two factors. First, the physicians' prognostic estimates are pessimistic. Second, the patients place the large majority of their estimates in the most optimistic category, thereby achieving low scatter. The authors suggest that the calculational simplicity of this decomposition, its informativeness, and the intuitive nature of its components make it a useful tool with which to analyze medical judgment.

Bias↗