Abstract 1908: Airway Pressure Release Ventilation Improves Pulmonary Blood Flow and Cardiac Output Following Cardiac Surgery for Congenital Heart Disease
Bibliographic record
Abstract
Introduction: Airway Pressure Release Ventilation (APRV) maintains a constant airway pressure (P aw ) with brief intermittent pressure reductions and permits spontaneous respiration without triggering the ventilator. Elevated P aw can critically reduce pulmonary blood flow (Q P ). We hypothesized that spontaneous ventilatory effort transmitted to the pleural space during APRV would result in a transient decrease in intrapleural pressure and increase Q P follow surgery for Tetralogy of Fallot or cavopulmonary connection (Glenn, Fontan). Methods: After obtaining IRB approval and patient consent, we studied children immediately following surgery. Q P and cardiac output (CO) were compared with APRV and positive pressure ventilation, with/without spontaneous ventilation. APRV was compared with positive pressure ventilation in the absence and presence of spontaneous respiratory effort in 4 × 30-minute phases. Oxygen consumption (VO 2 ) was measured (mass spectrometer), and Q P and CO calculated (Fick equation). Constant levels of PaCO 2 and mean P aw were targeted in all study phases. Results: Nineteen patients were enrolled in the study, 9 following repair of tetralogy of Fallot and 10 following a Glenn/Fontan operation. In the absence of spontaneous ventilation, there were no differences in Q P or any of the measured gas exchange or hemodynamic parameters. In the presence of spontaneous ventilation, there were significant differences in the measured parameters (Table). Conclusion: Ventilation with APRV (at comparable mean P aw ) improves Q P , and other gas exchange/hemodynamic variables compared with positive pressure ventilation in children following cardiac surgery. Although this study focused on tetralogy of Fallot repair and Glenn/Fontan operations, the improved cardiopulmonary interactions may be beneficial in other situations where hemodynamics are adversely modified by positive pressure ventilation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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 source (direct Gemma or distilled Codex), 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".