8 Pulmonary Vasodilatation with Intratracheal Sildenafil and Surfactant in Newborn Piglets with Pulmonary Hypertension
Bibliographic record
Abstract
Surfactant has been used effectively to improve oxygenation in hyaline membrane disease, and recently meconium aspiration pneumonia, which are commonly associated with pulmonary hypertension (PHT) in neonates. Sildenafil, a selective phosphodi-esterase type V inhibitor, has been administered systemically and intra-cheally at 0.5–2.0 mg/kg to dilate the pulmonary vasculature. The hemodynamic effects of surfactant and low-dose sildenafil, administered in combination have not been examined. To study the systemic and pulmonary effects of surfactant with or without sildenafil in newborn piglets with PHT induced by thromboxane A2 analog (U46619). Piglets (1–3 days old, 1.7–2.5 kg) were instrumented and mechanically ventilated for the continuous measurement of mean systemic and pulmonary arterial pressures (MAP and PAP respectively), heart rate and pulmonary artery flow (as cardiac output). Following stabilization, PHT was induced by continuous intravenous U46619 infusion (0.2–0.8 μg/kg/min) for 2 h. Piglets were randomized for intratracheal administration of surfactant (BLES, 4 mL/kg) with saline (control, n=6) or sildenafil (0.05 mg/kg, n=6) given after 1h of U46619 administration. Temporal changes of hemodynamic measurements were analyzed by 2-way ANOVA. U46619 treatment produced progressive PHT (161±19% of baseline) and surfactant administration did not improve the PHT. Surfactant and sildenafil combined improved PAP (32±3 vs. 42±3 mmHg of controls, P<0.05) along with a significantly reduced pulmonary vascular resistance (0.23±0.04 vs. 0.42±0.04 mmHg.kg.min/mL of controls). Significantly higher cardiac ouptut was found in the treatment group than controls (145±15 vs 107±15 mL/kg/min, respectively). No significant changes in heart rate, stroke volume, MAP and systemic vascular resistance were observed. The addition of low-dose sildenafil to surfactant is effective in alleviating PHT in newborn piglets. The combination of sildenafil and surfactant may be a novel therapeutic adjunct to critically ill neonates at risk for PHT when surfactant is used.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".