Intact cord resuscitation in newborns with congenital diaphragmatic hernia: insights from a lamb model
Bibliographic record
Abstract
Introduction Congenital diaphragmatic hernia (CDH) is a rare condition characterized by pulmonary hypoplasia, vascular dystrophy, and pulmonary hypertension at birth. Validation of the lamb model as an accurate representation of human CDH is essential to translating research findings into clinical practice and understanding disease mechanisms. This article emphasizes the importance of validating the lamb model to study CDH pathogenesis and develop innovative therapeutics. Material and methods At 78 days of gestation, the fetal lamb's left forelimb was exposed through a midline laparotomy and hysterotomy, and a supra diaphragmatic thoracotomy was performed to allow the digestive organs to ascend into the thoracic cavity. At 138 ± 3 days of gestation, lambs were delivered via a cesarean section; then, with umbilical cord intact during 1 hour, the lambs were mechanically ventilated with gentle ventilation in a pressure-controlled mode for 2 h. Results CDH lambs exhibited a lower left lung-to-body weight ratio of 5.3 (2.03), p < 0.05, and right lung-to-body weight ratio of 8.2 (3.1), p < 0.05. They reached lower Vt/kg (tidal volume per kg) during the course of the resuscitation period with 1.2 (0.7) ml/kg at 10 min and 3 (1.65) ml/kg at 60 min (p < 0.05). Compliance of the respiratory system was lower in CDH lambs with 0.5 (0.3) ml/cmH2O at 60 min (p < 0.05) and 0.9 (0.26) ml/cmH2O at 120 min (p < 0.05). Differences between pre- and postductal SpO2 were higher with 15.1% (21.4%) at 20 min and 6.7% (14.5%) at 80 min (p < 0.05). CDH lambs had lower differences between inspired and expired oxygen fractions with 4.55% (6.84%) at 20 min and 6.72% (8.57%) at 60 min (p < 0.05). CDH lamb had lower left ventricle [2.73 (0.5) g/kg, p < 0.05] and lower right ventricle [0.69 (0.8), p < 0.05] to left ventricle ratio. Discussion CDH lambs had significantly lower tidal volume than control lambs due to lower compliance of the respiratory system and higher airway resistance. These respiratory changes are characteristic of CDH infants and are associated with higher mortality rates. CDH lambs also exhibited pulmonary hypertension, pulmonary hypoplasia, and left ventricle hypoplasia, consistent with observations in human newborns. To conclude, our lamb model successfully provides a reliable representation of CDH and can be used to study its pathophysiology and potential interventions.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".