The use of catheter-tipped pressure transducers for chronic measurement of genital tract pressures in the ewe. I. Implantation technique, catheter performance and data analysis.
A computerised system for chronic in vivo monitoring of genital tract pressure in the ewe is described. Solid-state, catheter-tipped pressure transducers were surgically implanted in the uterine tube (ampulla), ipsilateral uterine horn and abdomen of five non-pregnant parous ewes. The catheters were connected to a portable computer which recorded the pressure at each location once per second and was programmed to analyse the data as mean pressure and area under the contraction curve over given periods. The catheters remained implanted for up to 129 days and 252 daily recordings were made. Analysis of spontaneous activity showed little variation in mean pressure of work done over four successive ten-minute periods. Although the amplitude of uterine contractions varied quite dramatically, chiefly in relation to variation in the plasma progesterone concentration, ampullary activity was unaffected by such changes. Genital tract pressures did not appear to be influenced by abdominal events. The catheters provoked minimal tissue reaction, and it is suggested that the system is suitable for chronic in vivo recording of genital tract pressure in the ewe.
Goddard
P J
PJ
Department of Surgery and Obstetrics Royal Veterinary College Hawkshead Lane North Mymms Hatfield Herts, UK.
Edward Allen
W
W