← Back to Tools
Neonatal Oxygenation

Pre/Post-Ductal Analyzer

Compare preductal and postductal SpO₂ / PaO₂ values to detect ductal shunting, screen for CCHD, and frame PPHN physiology with oxygenation index support.

Analyzer Inputs

Example values loaded — replace with real patient data.

mild gradient

Preductal > postductal gradient

Pattern suggests right-to-left ductal shunting (PPHN physiology until proven otherwise).

Δ SpO₂
7%
CCHD Screen
Fail
Δ PaO₂
18
OI / OSI
10.0 / 7.5
Interpretation Notes
  • Preductal saturation exceeds postductal saturation, suggesting blood desaturates after ductal mixing.
  • PaO₂ gradient is consistent with mild to moderate ductal shunting.
Suggested Actions
  • Evaluate for PPHN, pulmonary hypertension physiology, or significant parenchymal lung disease.
  • CCHD screen failed — urgent provider evaluation and confirmatory workup indicated.

Related PulmTools

Keep the neonatal oxygenation workflow moving

Pair pre/post-ductal interpretation with cord gases, capillary gases, oxygenation index, and neonatal respiratory references.

Open Neo/Peds Resources
Bedside pearls
  • • Preductal = right hand / wrist. Do not use the left hand.
  • • Postductal = foot or lower extremity.
  • • Pre > post suggests ductal shunting / PPHN physiology. Review the Neo/Peds Oxygenation Reference for target ranges and escalation context.
  • • Post > pre (reverse differential) is abnormal and should prompt urgent cardiac evaluation.
  • • Small differences in the first 10–15 minutes of life may be transitional and physiologic. Pair this with the Cord Gas Analyzer and CBG Analyzer when acid-base status is part of the question.