in brief

Fetal monitoring during cesarean section MARiAN LESLIE JOHN

S. W.

Department Uniwrsity







of Gyn.eculua and Obstetrics, School of Medicine, Baltimow,

The Johns Maryland


AT H o u G H a great deal of research and development has been expended in improving fetal monitoring during labor and vaginal delivery, very little conside)-ation has been given to fetal monitoring during the course of cesarean section delivery. Certainly the obstetric complications necessitating abdominal delivery, or the hazards associated with the required major anesthesia, pose high-risk situations for the f.etus.‘. ’ The time interval from initiation of anesthesia until section delivery occasionally extends to 30 or 45 minutes, yet fetal assessment during this dangerous period is rarely satisfactory. Utilization of the lower abdomen for the surgical procedure precludes the use of standard monitoring techniques other than the fetal scalp electrode. In this hospital, the latter technique is available in only 25 to 30 per cent of cases which come to cesarean section delivery. The risk of maternal infection associated with delivering t.he attached scalp electrode from the vagina through the uterine and abdominal incisions makes even this technique less than optimal for monitoring abdominal delivery. The purpose of this study was to determine whether placement of ultrasound transducers in positions other than the lower abdomen might be applicable to fetal monitoring during the preparatory steps and performance of cesarean section delivery. In an attempt to identify alternate positions for monitoring, Doppler ultrasound transducers* were applied to the upper abdomen, the flank, the back, and within the vagina in patients beyond 34 weeks of gestation. Transducers placed within the vagina were first


by a IO minute


in buffered

glutaraldehyde so1ution.t They were immediately rinsed in sterile water and dried with a sterile towel prior to being placed in the posterior fornix, adjacent to the presenting part. A viscous conducting jelly was applied liberally to the face of the transducer in all cases. The results of this study indicate that the fetal heart rate

is best



of 51 patients (90 per cent) monitored in this fashion. Placement of the transducer within the vagina permit-






midline of the abdomen just superior to the umbilicus. Acceptable fetal pulse signals were obtained in 46 out







25 out




(83.3 per cent). Attempts to detect the fetal pulse by placing monitors on the maternal lyack or flank ww generally unsuccessful. To date, 25 cesarean sections have been monitored successfully by placement of the transducer either on the upper abdomen or within the vagina. In obese patients and in fetal malpresentations, monitoring from the upper abdomen may be difficult, but generally can be achieved by fastening the transducer with adhesive tape into the position of maximal fetal pulse detection. In those occasional cases where the fetal pulse becomes undetectable, an assistant can adjust the position of the transducer while the lower abdomen is being prepared and draped for surgery. After drapassistant can manipulate the ing, the operative transducer probe from above and through the drapes. The experience to date has been that in those few cases where upper abdominal positioning is initially unsatisfacfory% vaginal placement is a suitable alterua~iw. Although disinfection of the probe was used in this pilot study. sterilization would be the optimal preparation for routine vaginal placement. This could be accomplished either with gas (ethylene oxide 12 pel cent and dichlorodifluoromethane 88 per cent) sterilization or 10 hour immersion in buffered glutaraldehyde. The monitors utilized in this study do not provide an instantaneous and written record of the fetal heart rate. However, the audible signal is such that the operating team is alerted to moderate or severe decelerations in the fetal pulse rate. Under such circumstances, fetal supportive measures can be instituted quickly. Precautions always must be taken to differentiate maternal from fetal pulse signals. In those operating units where maternal electrocardiographic monitoring is routinely employed, this is readily a

Fetal monitoring during cesarean section.

738 Communications in brief Fetal monitoring during cesarean section MARiAN LESLIE JOHN S. W. Department Uniwrsity ted MARINIS DE LEIGHTON C...
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