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Evaluation of new catheter systems for intrauterine pressure measurement
Letters to the Editor
References 1 2 3
43
Correspondence to:
Beck WW: Intestinal obstruction in pregnancy. Obstet Gynecol 43: 374, 1974. Munro A, Jones PF: Abdominal surgical emergencies in the puerperium. Br Med J 4: 691, 1975. Reece EA, Petrie RH: Colonic pseudo-obstruction following obstetrical surgery. Diagnostic Gynecol Obstet 4: 275, 1982.
S. Barik Department of Obstetrics and Gynaecology Heatherwood Hospital Ascot Berkshire SL5 8AA UK
Evaluation of new catheter systems for intrauterine pressure measurement
April
To the Editor
15th, 1993
We conducted a study to verify whether intrauterine pressure measurements with a new transducer tipped disposable catheter (Hewlett Packard HP13975A, Boblingen, Germany) would be reliable when two such catheters are used in the same patient and whether it would give comparable readings to that observed with an established catheter system of a different make (IntranII catheter, Utah Medical Products, USA) whose reliability for measuring intrauterine pressure has been documented [ 11. The main difference between the two catheters is the location of the pressure sensor. In the new catheter, the pressure sensor is located at the tip of the catheter whilst in the established catheter the pressure is transmitted from the uterus by a thin column of air to the transducer located outside the uterus at the base of the catheter. Eight women in labor were recruited for the study. In 5 women, the tips of the two new catheters (HP1 3975A) were tied together and placed in the same amniotic fluid pocket. In 3 other women the tip of the new catheter (HP13975A) and tip of an established catheter system (IntranII) 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 and the total active pressure for the whole labor was calculated. Of the total contractions (n = 222) experienced by
the 5 patients in the new versus new catheter group (HP13975A versus HP13975A), 95% showed a pressure difference of < 5 mmHg. In the new versus established catheter group (HP13975A versus IntranII), of the 222 contractions, 99% showed pressure differences of < 5 mmHg.
Table 1. Difference in the total active pressure for the complete labor in the 8 women as recorded by each catheter in the same amniotic fluid pocket. No. of contractions in each labor n
18 77 18 25 84
6 7 8 “Difference
53 125 44
Total active pressure for each labor in mmHg New vs. New (HP 13975A vs. HP 13975A)
Difference in total active pressure”
574 I585 210 421 231
593 1595 222 431 227
3.3 0.4 5.7 2.3 2. I
New vs. Established (HP13975A vs. Intranll) 609 584 1706 1755 460 453
4.1 2.9 1.5
in total active pressure
Higher total active pressure-Lower Higher Keywords: Catheters; Transducers.
Contractions;
0020-7293193/%06.00 0 1993 International Federation Printed and Published in Ireland
Intrauterine
= total active pressure
total active pressure
pressure; x 100%,
Int J Gynecol Obstet 42 of Gynecology
and Obstetrics
44
Letters to the Editor
The total active pressure for the whole labor in each woman was calculated by adding all the active pressure generated by the two catheters in each patient and the difference between the two catheters was calculated using the following equation: Highest total active pressue
_
Lowest total active pressure x 100%
Highest total active pressure This difference was < 6% in the new catheter versus new catheter group (HPl3975A versus HP13975A) and < 5% in the new versus established catheter group (HP13975A versus IntranII) (Table 1). The minor differences in active pressure observed in vivo between the two catheters is not related to the different catheter systems as this was seen even with the same catheter systems. This is unlikely to be of clinical significance, because management of labor is based on the frequency, duration and amplitude of contractions over a period of time rather than individual contractions. Our study showed no difference in frequency or
duration of contractions between the two catheters. This study concludes that the new transducer tip catheter (HP13975A) gives reliable pressure readings in vivo because it gives similar readings when compared with one of its own kind (HP13975A) or with an established catheter system (IntranII). Y.T. ChIa S. Andkumaran M. Yang
Dept. of Obstetrics & Gynaecology National University Hospital Lower Kent Ridge Road Singapore 05 11
References 1 Arulkumaran S, Yang M, Chia YT, Ratnam SS: Reliability of intrauterine pressure measurements. Obstet Gynecol 78: 800, 1991.
Correspondenceto: Y.T. Chia Department of Obstetrics and Gynaecology National University Hospital Lower Kent Ridge Road Singapore 0511
Massive dermoid cyst of the ovary: magnetic resonance imaging evaluation with ultrasonography and computed tomography correlations December 6th, 1992
To the Editor
The massive dermoid cyst has become uncommon as a result of the advantages of diagnostic imaging evaluation including ultrasonography (US). A case of ovarian dermoid cyst was encountered which almost filled abdominal cavity. In the diagnosis, magnetic resonance imaging (MRI) provided significant clinical management information with greater accuracy in comparison to US and computed tomography (CT). Keywords: Magnetic Ultrasonography.
resonance
imaging; Dermatoid
cyst;
0020-7293/93/$06.00 0 1993 International Federation of Gynecology and Obstetrics Printed and Published in Ireland
A 57-year-old Japanese women, gravida 2, para 2, was referred to the Gifu University Medical Center because of frequent episodes of fever (- 38”C), headache and abdominal pain for 2 weeks’ duration, and several years history of abdominal distension. An ultrasonographic examination revealed a thin-walled, ‘solid’ mass appearance with a homogeneous density measuring 18 cm in a diameter. The surface was smooth, at the right lateral side of which was a rounded echogenic mass causing acoustic shadowing and measured 4 x 4 x 4 cm in size. CT confirmed the ultrasonographic findings of large ‘solid’-appearing tumor containing a rounded solid mass. The
References 1 2 3
43
Correspondence to:
Beck WW: Intestinal obstruction in pregnancy. Obstet Gynecol 43: 374, 1974. Munro A, Jones PF: Abdominal surgical emergencies in the puerperium. Br Med J 4: 691, 1975. Reece EA, Petrie RH: Colonic pseudo-obstruction following obstetrical surgery. Diagnostic Gynecol Obstet 4: 275, 1982.
S. Barik Department of Obstetrics and Gynaecology Heatherwood Hospital Ascot Berkshire SL5 8AA UK
Evaluation of new catheter systems for intrauterine pressure measurement
April
To the Editor
15th, 1993
We conducted a study to verify whether intrauterine pressure measurements with a new transducer tipped disposable catheter (Hewlett Packard HP13975A, Boblingen, Germany) would be reliable when two such catheters are used in the same patient and whether it would give comparable readings to that observed with an established catheter system of a different make (IntranII catheter, Utah Medical Products, USA) whose reliability for measuring intrauterine pressure has been documented [ 11. The main difference between the two catheters is the location of the pressure sensor. In the new catheter, the pressure sensor is located at the tip of the catheter whilst in the established catheter the pressure is transmitted from the uterus by a thin column of air to the transducer located outside the uterus at the base of the catheter. Eight women in labor were recruited for the study. In 5 women, the tips of the two new catheters (HP1 3975A) were tied together and placed in the same amniotic fluid pocket. In 3 other women the tip of the new catheter (HP13975A) and tip of an established catheter system (IntranII) 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 and the total active pressure for the whole labor was calculated. Of the total contractions (n = 222) experienced by
the 5 patients in the new versus new catheter group (HP13975A versus HP13975A), 95% showed a pressure difference of < 5 mmHg. In the new versus established catheter group (HP13975A versus IntranII), of the 222 contractions, 99% showed pressure differences of < 5 mmHg.
Table 1. Difference in the total active pressure for the complete labor in the 8 women as recorded by each catheter in the same amniotic fluid pocket. No. of contractions in each labor n
18 77 18 25 84
6 7 8 “Difference
53 125 44
Total active pressure for each labor in mmHg New vs. New (HP 13975A vs. HP 13975A)
Difference in total active pressure”
574 I585 210 421 231
593 1595 222 431 227
3.3 0.4 5.7 2.3 2. I
New vs. Established (HP13975A vs. Intranll) 609 584 1706 1755 460 453
4.1 2.9 1.5
in total active pressure
Higher total active pressure-Lower Higher Keywords: Catheters; Transducers.
Contractions;
0020-7293193/%06.00 0 1993 International Federation Printed and Published in Ireland
Intrauterine
= total active pressure
total active pressure
pressure; x 100%,
Int J Gynecol Obstet 42 of Gynecology
and Obstetrics
44
Letters to the Editor
The total active pressure for the whole labor in each woman was calculated by adding all the active pressure generated by the two catheters in each patient and the difference between the two catheters was calculated using the following equation: Highest total active pressue
_
Lowest total active pressure x 100%
Highest total active pressure This difference was < 6% in the new catheter versus new catheter group (HPl3975A versus HP13975A) and < 5% in the new versus established catheter group (HP13975A versus IntranII) (Table 1). The minor differences in active pressure observed in vivo between the two catheters is not related to the different catheter systems as this was seen even with the same catheter systems. This is unlikely to be of clinical significance, because management of labor is based on the frequency, duration and amplitude of contractions over a period of time rather than individual contractions. Our study showed no difference in frequency or
duration of contractions between the two catheters. This study concludes that the new transducer tip catheter (HP13975A) gives reliable pressure readings in vivo because it gives similar readings when compared with one of its own kind (HP13975A) or with an established catheter system (IntranII). Y.T. ChIa S. Andkumaran M. Yang
Dept. of Obstetrics & Gynaecology National University Hospital Lower Kent Ridge Road Singapore 05 11
References 1 Arulkumaran S, Yang M, Chia YT, Ratnam SS: Reliability of intrauterine pressure measurements. Obstet Gynecol 78: 800, 1991.
Correspondenceto: Y.T. Chia Department of Obstetrics and Gynaecology National University Hospital Lower Kent Ridge Road Singapore 0511
Massive dermoid cyst of the ovary: magnetic resonance imaging evaluation with ultrasonography and computed tomography correlations December 6th, 1992
To the Editor
The massive dermoid cyst has become uncommon as a result of the advantages of diagnostic imaging evaluation including ultrasonography (US). A case of ovarian dermoid cyst was encountered which almost filled abdominal cavity. In the diagnosis, magnetic resonance imaging (MRI) provided significant clinical management information with greater accuracy in comparison to US and computed tomography (CT). Keywords: Magnetic Ultrasonography.
resonance
imaging; Dermatoid
cyst;
0020-7293/93/$06.00 0 1993 International Federation of Gynecology and Obstetrics Printed and Published in Ireland
A 57-year-old Japanese women, gravida 2, para 2, was referred to the Gifu University Medical Center because of frequent episodes of fever (- 38”C), headache and abdominal pain for 2 weeks’ duration, and several years history of abdominal distension. An ultrasonographic examination revealed a thin-walled, ‘solid’ mass appearance with a homogeneous density measuring 18 cm in a diameter. The surface was smooth, at the right lateral side of which was a rounded echogenic mass causing acoustic shadowing and measured 4 x 4 x 4 cm in size. CT confirmed the ultrasonographic findings of large ‘solid’-appearing tumor containing a rounded solid mass. The