1. UOG Journal Club: December 2018
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
T. Ghi, A. Dall’Asta, B. Masturzo, B. Tassis, M. Martinelli, N. Volpe, F. Prefumo, G. Rizzo, G. Pilu, L. Cariello, L. Sabbioni, A. M. Morselli-Labate, T. Todros and T. Frusca
Volume 52, Issue 6
Journal Club slides prepared by Dr Fiona Brownfoot
(UOG Editor for Trainees)

2. Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Introduction
Instrumental vaginal delivery by vacuum extraction is a widely performed obstetric procedure.
Although successful in most cases, a 4–6% failure rate has been reported following attempted vacuum delivery.
Fetal head malposition, mainly represented by occiput transverse and occiput posterior positions, is among the main determinants of failed fetal extraction using vacuum, as a high level of expertise is required in order to apply the suction cup on the flexion point.
Evaluation of the fetal head position using transabdominal ultrasound (TAS), either during labor or before instrumental delivery, has proven to be far more accurate than vaginal examination. 2

3. Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Aim of the study
To assess whether sonographic diagnosis of fetal head position before vacuum extraction can reduce the incidence of failed procedure and improve maternal and perinatal outcomes in women undergoing instrumental delivery by vacuum extraction. 3

4. Methods Study design Setting Participants Randomised controlled trial.
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Methods
Study design
Randomised controlled trial.
Setting
University of Parma, involving several Italian maternity units with over 2000 deliveries/year and a vacuum delivery rate ≥ 4%, from April 2014 to June 2017.
Participants
Included: nulliparous women >18 years with term (37+0 to 41+6 weeks of gestation) singleton pregnancy that required instrumental delivery.
Excluded: maternal age < 18 or > 50 years, any contraindication to instrumental vaginal delivery by vacuum extraction, fetal head station > +3 cm, emergency delivery necessary due to intrapartum fetal distress or when sonographic evaluation of fetal head position had been performed before randomization.

5. Methods Randomization Groups
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Methods
Randomization
All potentially eligible women were counseled regarding the study purpose and were provided with information material on admission. Informed consent for randomization was obtained in the early second stage of labor before active pushing.
Randomization was carried out after the decision to perform instrumental delivery was made by the attending physician.
Groups
Control group: fetal head position and station were determined by vaginal examination (VE) before vacuum cup positioning.
Intervention group: fetal occiput position was assessed by VE followed by transabdominal ultrasound (TAS) before vacuum cup positioning.
Fetal head position was classified into occiput anterior (OA), when the position was between 10 h and 2 h on a clock face, or non-OA position which included occiput posterior and transverse position.

6. Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Methods
Outcome
Primary outcome was incidence of failed vacuum extraction and need to perform emergency cesarean delivery.
Note: forceps are not performed in most units in Italy, therefore, if the vacuum failed, patients had Cesarean section.
Secondary outcomes: number of cup detachments, time between cup application and delivery, need for episiotomy, perineal tears involving the anal sphincter (third- or fourth-degree tears), postpartum hemorrhage (fall in hemoglobin level ≥ 4.0 g/dL within 24h from birth), neonatal trauma (intracranial hemorrhage, cephalohematoma, retinal hemorrhage, facial nerve palsy, brachial plexus injury and fractures), 5-min Apgar score < 7, neonatal acidosis (umbilical artery pH < 7.00 or base excess < −12 mEq/L), admission to neonatal intensive care unit and shoulder dystocia (failure to deliver the fetal shoulder with gentle downward traction on the fetal head) requiring additional obstetric maneuvers to effect delivery.

7. Results Study selection and characteristics Groups
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Results
Study selection and characteristics
222 women were enrolled over the study period.
1 patient was excluded after allocation as a decision for Cesarean section was made.
Groups
Control
132 (59.7%) to VE only
Intervention
89 (40.3%) to VE and ultrasound
*** The baseline characteristics table is now in the supp file which I don’t have access to.

8. Results Baseline characteristics
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Results
Baseline characteristics

9. Results Primary Outcome: Incidence of failed vacuum extraction
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Results
Primary Outcome:
Incidence of failed vacuum extraction
2 emergency Cesarean sections in the control group (VE only) and 0 in the intervention group (VE + ultrasound); P = 0.24.
Secondary Outcomes:
Higher incidence of episiotomy in intervention group; 86.5% vs 71.2%; P = 0.009.

10. Discussion Findings Study limitations
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Discussion
Findings
The rate of emergency Cesarean section due to failed vacuum delivery was not significantly different between women who underwent only VE of the fetal head position compared with those that had both VE and TAS assessment before delivery.
Incorrect diagnosis of fetal head position was increased in the control group.
Rate of episiotomy was higher in the VE plus TAS group.
Study limitations
The sample size was not reached. Perhaps this resulted from a change in practice in Italy where ultrasound is frequently used to determine fetal position in labour.
There was a low incidence of failed vacuum deliveries. Perhaps this reflects recruitment bias where practitioners only included patients with extractions considered to be easy. 10

11. Discussion Conclusion Implications for practice
Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Discussion
Implications for practice
VE plus ultrasound assessment of fetal head position before instrumental delivery does not reduce Cesarean section rate.
Combination of VE and TAS assessment is more accurate at diagnosing fetal position than VE alone.
Conclusion
VE plus ultrasound assessment compared to VE only prior to instrumental delivery does not reduce the instrumental failure rate and cesarean section.

12. Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.)
Ghi et al., UOG 2018
Discussion points
Given the low rate of failed instrumental deliveries, perhaps there was recruitment bias and only those with easier deliveries were included. Perhaps ultrasound might be useful for participants with more difficult instrumental deliveries and this should be the focus of future studies.
Ultrasound might be useful in cases in which the fetal head position is difficult to determine at vaginal examination rather than in every instrumental delivery. 12