title: Continuous systolic blood pressure monitoring by the difference in electrocardiogram and pulse oximetry in near-term, exteriorized goat fetuses.
abstract: OBJECTIVE
  Our purpose was to determine whether systolic arterial pressure, as predicted from the delay time from the electrocardiogram to pulse oximeter waveform, correlates with directly measured systolic blood pressure.
  
  
  METHODS
  Six Japanese Saanen goats at 120-125 days' gestation were used. Experiments were conducted in acutely operated animals under anesthesia. We placed catheters in the carotid artery and jugular vein, electrodes on the chest, and a pulse oximeter probe on the tongue. Systolic blood pressure (Psm), fetal heart rate (FHR), delay time (Td), and pulse oximeter waveform were monitored continuously, and the data were stored. Systolic blood pressure was estimated (Pse) by the simple linear equation of Td. Fetal blood pressure was decreased 10% by hydralazine and blood withdrawal. Correlation coefficients and the agreement between Psm and Pse were determined.
  
  
  RESULTS
  A significant correlation (P <.01) with good bias values (< 8 mmHg) and precision values (< 5 mmHg) was obtained between Psm and Pse in all animals. There was also a significant correlation between Psm and Pse with high coefficients for hydralazine (r(2) = 0.82 +/- 0.12) and for withdrawal (r(2) = 0.85 +/- 0.15). The correlations became slightly scattered in acidemia (pH < 7.25).
  
  
  CONCLUSIONS
  This technique has the potential to provide information on fetal blood pressure during labor and delivery on a beat-by-beat basis, which will aid in the interpretation of electronic FHR recordings.
authors.affiliation: Department of Obstetrics and Gynecology and Perinatal Center, Miyazaki Medical College, Miyazaki, Japan. hsameshima@fc.miyazaki-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sameshima
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kawagoe
authors.forename: Tsuyomu
authors.initials: T
authors.lastname: Ikenoue
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakamoto
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D001795:Blood Pressure Determination / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D006041:Goats / Q000196:embryology*; D006321:Heart / Q000196:embryology* / Q000502:physiology; D006340:Heart Rate, Fetal / Q000502:physiology; D006830:Hydralazine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D016014:Linear Models; D010092:Oximetry / Q000379:methods*; D011247:Pregnancy; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D006830:Hydralazine