Comparison of two intrauterine pressure catheters during labor.

OBJECTIVE To compare the Koala air-charged coupled catheter (Clinical Innovations, Inc., Murray, Utah) for monitoring intrauterine pressure (IUP) during active labor with an electronic pressure transducer-tip catheter, Intran Plus (Utah Medical Products, Midvale, Utah). STUDY DESIGN Simultaneous recordings with Koala and Intran catheters bound together at their tips were made in 18 term patients using comparably calibrated fetal monitors. RESULTS Coefficients of correlation between the two IUP catheter systems for mean uterine baseline, peak pressures, contraction frequency and duration were .78, .90, 1.00 and .63, respectively. Both systems functioned equally well in displaying abnormal uterine activity. Some difficulty was encountered in placing the combined catheters in the amniotic fluid space: 4 of 18 (23%) were placed outside the chorionic membrane, in the extraovular space. CONCLUSION Comparisons of the recordings from the Koala and Intran Plus catheters showed similar mean baseline uterine tone, peak pressures, contraction frequency and duration.