Transabdominal near infrared oximetry of hypoxic stress in fetal sheep brain in utero

AUTOR(ES)

Choe, Regine

FONTE

National Academy of Sciences

RESUMO

The feasibility of transabdominal near-infrared (NIR) spectroscopy for detecting and quantifying fetal hypoxia in utero is demonstrated in a pregnant ewe model. A frequency domain NIR spectroscopy probe, consisting of two detectors and six sources operating at three wavelengths (675, 786, and 830 nm), was placed on the maternal abdomen directly above the fetal head. Fetal hypoxia was indirectly induced through occlusion of uterine blood flow for ≈3 min. NIR photon diffusion measurements were made during a baseline period, during hypoxia of the fetus, and during recovery. Fetal blood samples were drawn from the fetal brachial artery and jugular veins at several time points during the cycle. Seven hypoxic cycles were induced in a total of five pregnant ewes. The NIR measurements were analyzed by using a two-layer diffusion model to deconvolve the fetal blood saturation from that of the pregnant ewe. Fetal hypoxia was detected. Good agreement was found between fetal blood saturation determined by the transabdominal NIR method and arterial and venous fetal blood saturation quantified from fetal blood samples by using a hemoximeter.

Documentos Relacionados

• The in utero left ventricle of the fetal sheep: the effects of isoprenaline.
• Brain imaging in awake infants by near-infrared optical topography
• Plasma proteins in fetal sheep brain: blood-brain barrier and intracerebral distribution.
• The effect of heart rate on in utero left ventricular output in the fetal sheep.
• Lesions in the upper lateral pons abolish the hypoxic depression of breathing in unanaesthetized fetal lambs in utero.