Mitral Doppler Indices Are Superior to Two-Dimensional Echocardiographic and Hemodynamic Variables in Predicting Responsiveness of Cardiac Output to a Rapid Intravenous Infusion of Colloid
Bibliographic record
Abstract
UNLABELLED: We hypothesized that mitral flow (MF) Doppler measurements could be used to predict cardiac output (CO) responsiveness to fluid challenge. Fourteen patients with normal systolic and diastolic function, scheduled for coronary artery bypass graft surgery, were evaluated as part of a pilot study in which preload was varied immediately before the beginning of cardiopulmonary bypass. A Validation group of 36 patients with different levels of systolic and diastolic function received a rapid infusion of 500 mL of 10% pentastarch. By use of transesophageal echocardiography, we measured left ventricular end-diastolic area, pulsed Doppler indices of the MF and pulmonary venous flow, and standard hemodynamic variables during acute volemic variations. A baseline measurement was first recorded, followed by measurements taken after a decrease (211 +/- 87 mL) and then an increase (176 +/- 149 mL) in preload (pilot study) and before and after 500 mL of pentastarch (validation study). In the pilot study, we found that a low velocity/time integral (VTI) E wave/A wave (E/A) ratio was associated with a larger increase in CO secondary to an increase in preload (r = 0.64, P < 0.05). Stepwise linear regression identified Doppler measurements of the mitral VTI E/A ratio as the most important variable to predict the increase in CO after fluid infusion. In the validation study, a mitral E/A ratio <1.26 before fluid infusion best predicted a 20% increase in stroke volume (receiver operating characteristic curve, 71%; P < 0.05), whereas no other hemodynamic or echocardiographic variable predicted preload responsiveness. We conclude that the MF Doppler filling pattern is an important factor to predict the increase in CO after intravascular fluid challenge in patients undergoing coronary artery bypass grafting. IMPLICATIONS: In the presence of low cardiac output, the clinician's ability to identify which patients are more likely to benefit from volume administration to improve hemodynamic status while avoiding fluid overload is important. The analysis of Doppler measurement of the mitral flow as an indirect indicator of the individual diastolic pressure/volume relationship may be useful to predict the intravascular volume responsiveness in patients undergoing coronary artery bypass graft surgery.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".