EP19.09: Use of a combined clinical and sonographic algorithm triage model in prolonged second stage of labour

To investigate whether an algorithm triage model could predict difficult assisted vaginal delivery in women with prolonged second stage of labour. The retrospective study included women who were assessed by a combined algorithm triage model (see figure 1) before vacuum extraction or forceps delivery at Kwong Wah Hospital, Hong Kong, between February 1, 2023 and January 31, 2024. Fetal head position, station and descent were assessed using transabdominal and transperineal ultrasound. Difficult (≥ 3 pulls) and easy (<3 pulls) deliveries were compared using Mann Whitney U test. All 51 women had successful assisted vaginal delivery. 12 (23.5%) and 39 (76.5%) had difficult and easy procedure respectively. 2 women with difficult procedures were excluded because of incomplete data. In the difficult delivery group, the median AoP was 141° (131°-179°) between contractions, 164° (143°-178°) with pushing. The median HPD was 30mm (21-37mm) between contractions, 24mm (12-31mm) with pushing. Median △HPD was 6mm (4-14mm). 9 fetus (90%) were “head-up”. For the easy procedure group, the median AoP was 158° (131°- 178°) between contractions, 172° (144°-214°) with pushing. The median HPD was 28mm (16-45mm) between contractions, 20mm (11- 36mm) with pushing. Median △HPD was 8mm (0.2- 17mm). 35 fetuses (89.7%) were “head-up”. Only AoP with pushing showed statistically significant difference (p < 0.05) between the two groups. Of all sonographic parameters, angle of progression with pushing may be the most sensitive predictor of difficult assisted vaginal delivery. Further studies with a larger sample size are needed to refine the algorithm model. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.