Intravenous Sildenafil Is a Potent Pulmonary Vasodilator in Children With Congenital Heart Disease
Bibliographic record
Abstract
BACKGROUND: Increased pulmonary vascular resistance (PVR) because of congenital heart disease (CHD) may be caused by a dysfunction in endogenous pulmonary endothelial nitric oxide (NO) production. In other forms of pulmonary vascular disease with increased PVR, an elevated activity of a phosphodiesterase type 5 (PDE-5), responsible for the degradation of cyclic guanidine monophosphate (cGMP), the second messenger of endothelially produced NO, has been demonstrated. This study compares the effects of inhaled NO before and after the specific inhibition of the PDE-5 by intravenous sildenafil (Viagra) in pre- and postoperative children with increased PVR because of CHD. METHODS AND RESULTS: 12 children with congenital heart disease (age 0.2 to 15.7 years, median 2.4 years) and increased mean pulmonary arterial pressure, and 12 postoperative children (age 0.11 to 0.65 years, median 0.32 years) with increased PVR (8.3+/-1.0 Wood Units*m2) were studied during cardiac catheterization ("cath laboratory"), or within 2 hours after return from cardiac surgery ("post op"), respectively. All were sedated, tracheally intubated and paralyzed. During alveolar hyperoxygenation (FiO2=0.65), the effects of inhaled NO (20 ppm) were compared before and after the stepwise infusion of sildenafil ("cath laboratory", 1 mg/kg; post op, 0.25 mg/kg). Intravenous sildenafil more effectively reduced PVR than NO (11.5% versus 4.3% in the "cath laboratory" patient group, P<0.05, and 25.8% versus 14.6% in the post op patient group, P=0.09. The increase in cGMP in response to NO was potentiated (2- to 2.4-fold) by PDE-5 inhibition. While the vasodilating effects of sildenafil showed pulmonary selectivity, its infusion was associated with increased intrapulmonary shunting in the postoperative patients (Qs/Qt=16.5+/-4.7% to 25.5+/-18.2% P=0.04). CONCLUSIONS: Intravenous sildenafil is as effective as inhaled NO as a pulmonary vasodilator in children with congenital heart disease. Although clinically insignificant in this study, increased intrapulmonary shunting with sildenafil may be disadvantageous in some patients after CHD 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 | 0.000 | 0.000 |
| 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 | 0.000 |
| 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".