title: Scalp blood flow measured by the xenon clearance technique and transcutaneous PO2 in the fetal lamb.
abstract: Scalp blood flow and transcutaneous (tc) PO2 were measured in four fetal lambs at 130-135 days of gestation. Scalp blood flow was measured by the xenon clearance technique using a technetium source to correct for changes in distance from the detector. The effect of circular pressure, the so-called "tonsure effect" on scalp flow and tcPO2, was evaluated by pressing a ring on the scalp. A circular pressure between 20-30 mmHg markedly reduced local scalp blood flow and was sufficient to reduce tcPO2 to zero. We found evidence of significant recirculation of xenon in the fetal circulation indicating right-left shunting. This study showed that the tonsure effect seriously affected scalp blood flow and tcPO2 in the fetus.
mesh_terms: D000818:Animals; D005260:Female; D005312:Fetal Blood / Q000032:analysis*; D005323:Fetal Monitoring / Q000379:methods / Q000592:standards*; D010100:Oxygen / Q000097:blood; D011247:Pregnancy; D012039:Regional Blood Flow; D012535:Scalp / Q000098:blood supply*; D012756:Sheep; D013314:Stress, Mechanical; D014980:Xenon Radioisotopes
chemical_list: D014980:Xenon Radioisotopes; D010100:Oxygen