OF OBSTETRICS AND GYNAECOLQCV AUST.AND N.Z. JOURNAL
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the quantity of electricity per pulse should not exceed 2.5 millicoulombs (2.5 milliamp seconds), as it is considered that detrimental effects are related to the product of current and time. However, no maximum current is set, and McCutchan (10) has recorded currents of up to 7 amps through the moist nose of cattle. McCutchan (10) discussed 4 reports of humans being rendered unconscious through head contact with live fence wires, and one instance of a sheep dog who died after receiving two pulses through the belly as it jumped over an electric fence. The dog ran for a short distance, then seemed to succumb to paralysis which spread from the hindquarters towards the head. Respiratory arrest ensued, then finally cardiac arrest. Nervous tissue is a better conducter of electricity than blood, muscle or skin, in that order, and damage to the central nervous system could possibly explain the relatively delayed deaths of the sheep dog and the 12-week fetus in this case report.
References 1. Mazor M, Leiberman JR. Abortion caused by electrical current.
Arch Gynecol Obstet 1987; 241: 71-72. 2. Jaffe R, Fejgin M, Ben Aderet N. Fetal death in early pregnancy due to electric current. Acta Obstet Gynecol Scand 1986; 65: 283. 3. Rees WD. Pregnant women struck by lightning. Br M J 1965; 1: 103-104. 4. Waikato mains operated electric fence running on a voltage of 240 volts and power of 10 watts, frequency 50 Hz. 5. ASUM Standard BPD Chart August 1990. Australasian Society for Ultrasound in Medicine. 6. Jeanty P et a1 in Sabbagha RE. Diagnostic Ultrasound Applied to Obstetrics & Gynecology. 2nd Edition Lippincott 1987. 7. After Streeter in Keeling Jean W (Ed.) Fetal and Neonatal Pathology. Springer Verlag 1987. 8. Leiberman JR, Mazor MJ, Haiam E, Maor E, Insler V. Electrical accidents during pregnancy. Obstet Gynecol 1986; 67: 861-863. 9. Cwinn AA, Cantrill SV. Lightning injuries. J Emerg Med 1985; 2: 379-388. 10. McCutchan JC. Electric Fence Design Principles. University of Melbourne 1980.
Aust NZ J Obstet Gynaecol 1992: 32: 4: 378
External Cephalic Version - A Cautionary Tale Anthony Stock’, Michael RogersZ and Wai Ming Wong’ Department of Obstetrics and Gynaecology, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
With recent evidence suggesting that even in carefully selected cases there is an increase in perinatal morbidity following vaginal breech delivery (1) there has been a resurgence in the popularity of performing external cephalic version (ECV) at term using tocolysis (2). The contraindications to attempt a n ECV are well established (3). We report a case where a patient admitted for ECV was found to have placenta praevia despite repeated antenatal ultrasound scans.
Case report The patient, a 39-year-old multiparous Chinese woman, was first seen at our hospital at 34 weeks’ gestation with a breech presentation. There was no history of vaginal bleeding. She had previously been 1. Visiting Lecturer. 2. Senior Lecturer. 3. Medical Officer. Address for correspondence: Dr. Anthony Stock, Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
attending another hospital where serial ultrasound scans had been performed following the discovery of a 3 cm fibroid anteriorly in the lower part of the uterus. At 36 weeks’ gestation the presentation remained breech. A further ultrasound scan was therefore performed prior to admission for ECV. This was reported as showing a fundal placenta and normal liquor volume (figure 1). The estimated fetal weight was 3,400 g. There was no sign of a fibroid in the lower pole of the uterus. It was decided to admit the patient for ECV at 37 weeks’ gestation. Ultrasound scan immediately prior to version again revealed a thin fundal placenta. However there also appeared to be placental tissue in the lower segment of the uterus posterior (figure 2). It was not possible to clearly demonstrate a connection between the 2 placental masses. A vaginal ultrasound was performed which confirmed the presence of a posterior type 1 placenta praevia with the placental margin 1.1 cm from the internal 0s. A diagnosis of placenta praevia due to a succenturiate lobe of placenta was made. Version was therefore not attempted. The baby, a healthy 3,750 g male was delivered by Caesarean section at 38 weeks’
ANTHONY STOCK
Figure 1. Longitudinal ultasound scan of fundus demonstrating placenta.
ET AL
379
DISCUSSION This case serves to illustrate several important points in relationship to information gathering. This patient was scanned on a number of occasions by different people in 2 different hospitals. Initially the principal indication for ultrasonic examination was to assess growth of a fibroid in the lower pole of the uterus. At 36 weeks’ gestation the indication for the scan was to exclude any contraindication to ECV. Despite the fact that on each occasion attention was focussed on the lower pole of the uterus, the diagnosis of placenta praevia was missed. It is probable that the dearly visible, fundal placenta led to the erroneous conclusion that there was no placenta praevia. However, despite the fact that it is rare to find a placenta which both the fundus and extends into the lower segment or to find a succenturiate lobe, the absence of placenta praevia should be a diagnosis of exclusion not of inference; the lower segment should be scanned specifically to exclude the presence of placental tissue. As in this case, extrapolation from one piece of information may lead to a false conclusion, which potentially could have serious implications for the patient. We would therefore recommend that prior to ECV ultrasound is performed specifically to exclude placenta praevia, as opposed to scanning to localize the placenta.
References Figure 2. Longitudinal scan of lower pole of the uterus demonstrating placental tissue adjacent to the internal 0s. Type 1 placenta praevia was confirmed by vaginal ultrasound scan.
gestation* At the time Of Operation the was found not t o have succenturiate lobe but to extend to within 1 cm of the internal os, being abnormally thin and adherent in its lower part.
1. Mahomed K , Seeras R, Coulson R. Breech delivery of infants weighing more than 2000 g. A case controlled prospective analysis of 751 patients. Int J Gynecol Obstet 1991; 32: 111-115. 2. Mahomed K, Seeras R, Coulson R. External cephalic version at term. A randomized controlled trial using tocolysis. Br J Obstet Gynaecol 1991; 98: 8-13. 3. Hofmeyer GJ. Breech presentation and abnormal lie in late pregnancy. In Effective Care in Pregnancy and Childbirth (Chalmers I. Enkin M and Keirse MJNC eds). Oxford Universitv Press 1989; 664.
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the quantity of electricity per pulse should not exceed 2.5 millicoulombs (2.5 milliamp seconds), as it is considered that detrimental effects are related to the product of current and time. However, no maximum current is set, and McCutchan (10) has recorded currents of up to 7 amps through the moist nose of cattle. McCutchan (10) discussed 4 reports of humans being rendered unconscious through head contact with live fence wires, and one instance of a sheep dog who died after receiving two pulses through the belly as it jumped over an electric fence. The dog ran for a short distance, then seemed to succumb to paralysis which spread from the hindquarters towards the head. Respiratory arrest ensued, then finally cardiac arrest. Nervous tissue is a better conducter of electricity than blood, muscle or skin, in that order, and damage to the central nervous system could possibly explain the relatively delayed deaths of the sheep dog and the 12-week fetus in this case report.
References 1. Mazor M, Leiberman JR. Abortion caused by electrical current.
Arch Gynecol Obstet 1987; 241: 71-72. 2. Jaffe R, Fejgin M, Ben Aderet N. Fetal death in early pregnancy due to electric current. Acta Obstet Gynecol Scand 1986; 65: 283. 3. Rees WD. Pregnant women struck by lightning. Br M J 1965; 1: 103-104. 4. Waikato mains operated electric fence running on a voltage of 240 volts and power of 10 watts, frequency 50 Hz. 5. ASUM Standard BPD Chart August 1990. Australasian Society for Ultrasound in Medicine. 6. Jeanty P et a1 in Sabbagha RE. Diagnostic Ultrasound Applied to Obstetrics & Gynecology. 2nd Edition Lippincott 1987. 7. After Streeter in Keeling Jean W (Ed.) Fetal and Neonatal Pathology. Springer Verlag 1987. 8. Leiberman JR, Mazor MJ, Haiam E, Maor E, Insler V. Electrical accidents during pregnancy. Obstet Gynecol 1986; 67: 861-863. 9. Cwinn AA, Cantrill SV. Lightning injuries. J Emerg Med 1985; 2: 379-388. 10. McCutchan JC. Electric Fence Design Principles. University of Melbourne 1980.
Aust NZ J Obstet Gynaecol 1992: 32: 4: 378
External Cephalic Version - A Cautionary Tale Anthony Stock’, Michael RogersZ and Wai Ming Wong’ Department of Obstetrics and Gynaecology, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
With recent evidence suggesting that even in carefully selected cases there is an increase in perinatal morbidity following vaginal breech delivery (1) there has been a resurgence in the popularity of performing external cephalic version (ECV) at term using tocolysis (2). The contraindications to attempt a n ECV are well established (3). We report a case where a patient admitted for ECV was found to have placenta praevia despite repeated antenatal ultrasound scans.
Case report The patient, a 39-year-old multiparous Chinese woman, was first seen at our hospital at 34 weeks’ gestation with a breech presentation. There was no history of vaginal bleeding. She had previously been 1. Visiting Lecturer. 2. Senior Lecturer. 3. Medical Officer. Address for correspondence: Dr. Anthony Stock, Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
attending another hospital where serial ultrasound scans had been performed following the discovery of a 3 cm fibroid anteriorly in the lower part of the uterus. At 36 weeks’ gestation the presentation remained breech. A further ultrasound scan was therefore performed prior to admission for ECV. This was reported as showing a fundal placenta and normal liquor volume (figure 1). The estimated fetal weight was 3,400 g. There was no sign of a fibroid in the lower pole of the uterus. It was decided to admit the patient for ECV at 37 weeks’ gestation. Ultrasound scan immediately prior to version again revealed a thin fundal placenta. However there also appeared to be placental tissue in the lower segment of the uterus posterior (figure 2). It was not possible to clearly demonstrate a connection between the 2 placental masses. A vaginal ultrasound was performed which confirmed the presence of a posterior type 1 placenta praevia with the placental margin 1.1 cm from the internal 0s. A diagnosis of placenta praevia due to a succenturiate lobe of placenta was made. Version was therefore not attempted. The baby, a healthy 3,750 g male was delivered by Caesarean section at 38 weeks’
ANTHONY STOCK
Figure 1. Longitudinal ultasound scan of fundus demonstrating placenta.
ET AL
379
DISCUSSION This case serves to illustrate several important points in relationship to information gathering. This patient was scanned on a number of occasions by different people in 2 different hospitals. Initially the principal indication for ultrasonic examination was to assess growth of a fibroid in the lower pole of the uterus. At 36 weeks’ gestation the indication for the scan was to exclude any contraindication to ECV. Despite the fact that on each occasion attention was focussed on the lower pole of the uterus, the diagnosis of placenta praevia was missed. It is probable that the dearly visible, fundal placenta led to the erroneous conclusion that there was no placenta praevia. However, despite the fact that it is rare to find a placenta which both the fundus and extends into the lower segment or to find a succenturiate lobe, the absence of placenta praevia should be a diagnosis of exclusion not of inference; the lower segment should be scanned specifically to exclude the presence of placental tissue. As in this case, extrapolation from one piece of information may lead to a false conclusion, which potentially could have serious implications for the patient. We would therefore recommend that prior to ECV ultrasound is performed specifically to exclude placenta praevia, as opposed to scanning to localize the placenta.
References Figure 2. Longitudinal scan of lower pole of the uterus demonstrating placental tissue adjacent to the internal 0s. Type 1 placenta praevia was confirmed by vaginal ultrasound scan.
gestation* At the time Of Operation the was found not t o have succenturiate lobe but to extend to within 1 cm of the internal os, being abnormally thin and adherent in its lower part.
1. Mahomed K , Seeras R, Coulson R. Breech delivery of infants weighing more than 2000 g. A case controlled prospective analysis of 751 patients. Int J Gynecol Obstet 1991; 32: 111-115. 2. Mahomed K, Seeras R, Coulson R. External cephalic version at term. A randomized controlled trial using tocolysis. Br J Obstet Gynaecol 1991; 98: 8-13. 3. Hofmeyer GJ. Breech presentation and abnormal lie in late pregnancy. In Effective Care in Pregnancy and Childbirth (Chalmers I. Enkin M and Keirse MJNC eds). Oxford Universitv Press 1989; 664.
