Sangalli, MMcLean, AllanPeek, MRivory, L.Le Couteur, D2015-12-130143-4004http://hdl.handle.net/1885/77246In order to estimate the placental barrier to gas transfer, a novel carbon monoxide (CO) wash-in method was used to estimate the permeability-surface area (PS) product for the transfer of gas across the foetal circulation in the perfused human term placenta. The PS product for CO was 0.0096 ± 0.006 ml/s/g or 0.012 ± 0.007 ml/s/g using compartmental or Crone-Renkin analysis, respectively. Using this result and a published estimate of the placental capillary surface area, the permeability coefficient to CO across the foetal circulation was found to be approximately 4 × 10-5 cm/s. This result is compatible with the hypothesis that the foetal circulation of the human placenta imposes a potentially significant barrier to gas transfer.Keywords: carbon monoxide; oxygen; article; blood placenta barrier; capillary permeability; compartment model; controlled study; female; fetus circulation; gas diffusion; human; human tissue; hypothesis; oxygen transport; permeability; placenta circulation; placent200310.1053/plac.2002.08772015-12-11