The OdonAssist inflatable device for assisted vaginal birth-the ASSIST II study (United Kingdom).

BACKGROUND: Decreasing rates of assisted vaginal birth have been paralleled with increasing rates of cesarean deliveries over the last 40 years. The OdonAssist is a novel device for assisted vaginal birth. Iterative changes to clinical parameters, device design, and technique have been made to improve device efficacy and usability. OBJECTIVE: This study aimed to determine if the feasibility, safety, and efficacy of the OdonAssist device were sufficient to justify conducting a future randomized controlled trial. STUDY DESIGN: An open-label nonrandomized study of 104 participants having a clinically indicated assisted vaginal birth using the OdonAssist was undertaken at Southmead Hospital, Bristol, United Kingdom. Data were also collected from participants who consented to participate in the study but for whom trained OdonAssist operators were not available, providing a nested cohort. The primary clinical outcome was the proportion of births successfully expedited with the OdonAssist. Secondary outcomes included clinical, patient-reported, operator-reported, device and health care utilization. Neonatal outcome data were reviewed at day 28, and maternal outcomes were investigated up to day 90. Given that the number of successful OdonAssist births was ≥61 out of 104, the hypothesis of a poor rate of 50% was rejected in favor of a good rate of ≥65%. RESULTS: Between August 2019 and June 2021, 941 (64%) of the 1471 approached, eligible participants consented to participate. Of these, 104 received the OdonAssist intervention. Birth was assisted in all cephalic vertex fetal positions, at all stations ≥1 cm below the ischial spines (with or without regional analgesia). The OdonAssist was effective in 69 of the 104 (66%) cases, consistent with the hypothesis of a good efficacy rate. There were no serious device-related maternal or neonatal adverse reactions, and there were no serious adverse device effects. Only 4% of neonatal soft tissue bruising in the successful OdonAssist group was considered device-related, as opposed to 20% and 23% in the unsuccessful OdonAssist group and the nested cohort, respectively. Participants reported high birth perception scores. All practitioners found the device use to be straightforward. CONCLUSION: Recruitment to an interventional study of a new device for assisted vaginal birth is feasible; 64% of eligible participants were willing to participate. The success rate of the OdonAssist was comparable to that of the Kiwi OmniCup when introduced in the same unit in 2002, meeting the threshold for a randomized controlled trial to compare the OdonAssist with current standard practice. There were no disadvantages of study participation in terms of maternal and neonatal outcomes. There were potential advantages of using the OdonAssist, particularly reduced neonatal soft tissue injury. The same application technique is used for all fetal positions, with all operators deeming the device straightforward to use. This study provides important data to inform future study design.

Novel device for assisted vaginal birth: using integrated qualitative case study methodology to optimise Odon Device use within a feasibility study in a maternity unit in the Southwest of England.

OBJECTIVE: When novel devices are used 'in human' for the first time, their optimal use is uncertain because clinicians only have experience from preclinical studies. This study aimed to investigate factors that might optimise use of the Odon Device for assisted vaginal birth. DESIGN: We undertook qualitative case studies within the ASSIST Study, a feasibility study of the Odon Device. Each 'case' was defined as one use of the device and included at least one of the following: observation of the attempted assisted birth, and an interview with the obstetrician, midwife or woman. Data collection and thematic analysis ran iteratively and in parallel. SETTING: Tertiary referral National Health Service maternity unit in the Southwest of England. PARTICIPANTS: Women requiring a clinically indicated assisted vaginal birth. INTERVENTION: The Odon Device, an innovative device for assisted vaginal birth. PRIMARY AND SECONDARY OUTCOME MEASURES: Determining the optimal device technique, device design and defining clinical parameters for use. RESULTS: Thirty-nine cases involving an attempted Odon-assisted birth were included in this study, of which 19 resulted in a successful birth with the device. Factors that improved use included optimisation of device technique, device design and clinical parameters for use. Technique adaptations included: applying the device during, rather than between, contractions; having a flexible approach to the application angle; and deflating the air cuff sooner than originally proposed. Three design modifications were proposed involving the deflation button and sleeve. Although use of the device was found to be appropriate in all fetal positions, it was considered contraindicated when the fetal station was at the ischial spines. CONCLUSIONS: Case study methodology facilitated the acquisition of rapid insights into device function in clinical practice, providing key insights regarding use, design and key clinical parameters for success. This methodology should be considered whenever innovative devices are introduced into clinical practice. TRIAL REGISTRATION NUMBER: ISRCTN10203171.