ANIMAL STUDIES FOR INTRAPARTUM BIOCHEMICAL MONITORING - ARTIFICIAL UMBILICAL CIRCULATION

S. Schmidt
1988 Journal of Perinatal Medicine  
The electrode for the measurement of the transcutaneous partial pressure of carbon dioxide (tcPCO2 ) is an additional instrument for the supervision of the fetus during labour (5, 9, 12) . The investigation of certain aspects of the tcPCCm onitoring in the human fetus during labour was performed during a number of animal experiments in order to study the electrode under defined conditions. The study of the response of electrochemical sensors have been shown to be limited during clinical trials
more » ... ng clinical trials to some extent (13). The aim of this paper is to demonstrate the reliability of a combined tcPCO 2 /PCO 2 sensor to measure the PCO and PO~ in arterial blood over a wide range of values. The variability of the gases was achieved by an artificial umbilical circulation via a membranlung (1,2,7,11). Method The animal experiments were performed using twelve premature lambs, gestational age 125 to 128 days of gestation (caesarian section in epidural anesthesia). The delivered premature lambs directyl thereafter were connected to a perfusion circuit using catheters that were implanted into the umbilical artery and umbilical vein (thinwalled, largewalled catheters embedding stainless steel springs (14). The perfusion circuit included an 0,4 m Scimed -Kolobow membrane lung, 3/16 Polyurethan-tubing and a mechanical pump. The priming volume of 160 ml was maternal blood. The flow rate in the extracorporeal circuit was initially regulated aiming at a PCO 2 of 45 to 55 mm HG. PCO 2 values in the extracorporeal circuit were measured by intermitten blood samples from the arterial line and by a sensor and a flow chamber that measured the PCO^ and PO> values at a measuring temperature of 37 °C. The circuit and the animal were thermostated at 37OC by means of an incubator. Transcutaneous electrodes were placed on the fetal head by the glue technique (4). The measuring site was prepared in the following way: hair was removed and the measuring site was cleansed from mucus and blood using squabs. Fixation rings thereafter were applied on this measuring site using butyl-
doi:10.1515/jpme.1988.16.s1.87 pmid:3225726 fatcat:5hpjumeoqjctlitosomsjixq3u