title: Doppler sonographic examination of uterine and placental perfusion in cows in the last month of gestation and effects of epidural anesthesia and isoxsuprine.
abstract: The massive increase in size of the fetus and uterus in the last trimester is accompanied by an increasing demand for nutrients and oxygen, and it is assumed that this demand is met by increasing uterine and fetal perfusion. The goals of this study were to measure the perfusion of the uterine arteries and the placentomes in the last month of gestation and to investigate the effect of epidural anesthesia and isoxsuprine on perfusion. During the last month of gestation, eight Braunvieh cows underwent nine color Doppler sonographic examinations of the uterine arteries to determine diameter (DM), pulse rate (PR), resistance index, time-averaged maximum blood flow velocity (TAMV), and blood flow volume (BFV), and power-mode Doppler sonography was used to determine perfusion of placentomes. The PR increased (P < 0.001), and the BFV and TAMV of the ipsilateral uterine artery decreased between 4.5 and 0.5 weeks prepartum (BFV, 236.8 ± 65.80 and 208 ± 41.52 cm(3)/s, P < 0.01; TAMV, 140.0 ± 26.53 cm/s and 125.2 ± 18.46 cm/s, P < 0.05). After sonographic examination, the cows received epidural administration of local anesthetic (100-mg lidocaine) in the sacrococcygeal space or isoxsuprine (200 mg/cow, iv), and the sonographic measurements were repeated 30 minutes later. After epidural anesthesia, the TAMV and BFV of the contralateral uterine artery increased by 5.4% (P < 0.05) and 7.9% (P < 0.01). In the placentomes of the gravid uterine horn, the relative placentome perfusion and the color pixel grading (Cp) increased by 10.1% (P < 0.05) and 11.5% (P < 0.01) after epidural anesthesia. After isoxsuprine, the DM, PR, and BFV increased by 4.7%, 49.3%, and 16.9% in the ipsilateral uterine artery and by 10.8%, 48.7%, and 22.8%, respectively in the contralateral uterine artery. The TAMV of the ipsilateral uterine artery increased by 7.1% (P < 0.01), and the resistance index decreased in both uterine arteries (ipsilateral 24.2%, contralateral 14.9%, both P < 0.00001). Isoxsuprine increased the relative placentome perfusion and the Cp of the placentomes by 18.1% and 18.3% in the gravid horn and by 10.2% and 24.2% in the nongravid horn. Blood flow variables changed little in the last month of gestation. However, epidural anesthesia and isoxsuprine caused changes in uterine and placentome perfusion that suggest improvement of placental nutrient and oxygen supply to the fetus.
authors.affiliation: Large Animal Reproduction Unit, Clinic for Reproductive Medicine, Department of Farm Animals, Vetsuisse Faculty, University of Zurich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Kim-Egloff
authors.affiliation: Ambulatory and Stationary Clinic, Vetsuisse Faculty, Department of Farm Animals, University of Zurich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Hässig
authors.affiliation: Veterinary Physiology, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Bruckmaier
authors.affiliation: Large Animal Reproduction Unit, Clinic for Reproductive Medicine, Department of Farm Animals, Vetsuisse Faculty, University of Zurich, Switzerland. Electronic address: ubleul@vetclinics.uzh.ch.
authors.forename: U
authors.initials: U
authors.lastname: Bleul
mesh_terms: D000767:Anesthesia, Epidural / Q000662:veterinary*; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects / Q000662:veterinary; D002417:Cattle; D005260:Female; D005865:Gestational Age; D007556:Isoxsuprine / Q000494:pharmacology*; D010920:Placenta / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000187:drug effects; D011247:Pregnancy; D012039:Regional Blood Flow / Q000187:drug effects; D018615:Ultrasonography, Doppler, Color; D016216:Ultrasonography, Prenatal / Q000662:veterinary; D055988:Uterine Artery / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000502:physiology; D014599:Uterus / Q000098:blood supply / Q000000981:diagnostic imaging / Q000187:drug effects
chemical_list: D007556:Isoxsuprine
keywords: Color Doppler ultrasound; Gestation; Intrauterine resuscitation; Placentome; Power Doppler ultrasound; Uterine artery