Evaluation of new catheter systems for intrauterine pressure measurement.

To verify the reliability of intrauterine pressure recordings by a newly available intrauterine catheter. In five women in labor the tips of the two newly available catheters (Hewlett Packard HP 13975 A) were tied together and placed in the same amniotic fluid pocket. In three other women the tip of the new catheter (HP) and tip of an established catheter system (Intran II) were tied and placed in the uterine cavity above the fetal head. The difference in active pressure recorded by the two catheters for each contraction in all 8 women was calculated. The total active pressure recorded for each patient for the whole labor by the two catheter was calculated. The active pressure difference for individual contractions was less than 5 mm Hg in 95% of contractions (n = 222) with the two new catheters (HP versus HP) and 99% when the new catheter was compared with the established catheter system (HP versus Intran II) (n = 222). The total active pressure in each labor differed by 0.4% to 5.4% (n = 5) and 1.4% to 4.1% (n = 3) respectively when similar (new HP versus new HP) and different catheter systems (new HP versus established Intran II) were used. The new transducer tip catheter gives reliable pressure readings in-vivo. (n = 3) respectively when similar (new HP versus new HP) and different catheter systems (new HP versus established Intran II) were used. The new transducer tip catheter gives reliable pressure readings in-vivo.