The Odon Device™ for assisted vaginal birth: a feasibility study to investigate safety and efficacy-The ASSIST II study

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.

Women's and midwives' views on the optimum process for informed consent for research in a feasibility study involving an intrapartum intervention: a qualitative study

BACKGROUND

Recruitment to intrapartum research is complex. Women are expected to understand unfamiliar terminology and assess potential harm versus benefit to their baby and themselves, often when an urgent intervention is required. Time pressures of intrapartum interventions are a major challenge for recruitment discussions taking place during labour, with research midwives expected to present, discuss and answer questions whilst maintaining equipoise. However, little is known about these interactions. An integrated qualitative study (IQS) was used to investigate information provision for women invited to participate in the Assist II feasibility study investigating the OdonAssist™-a novel device for use in assisted vaginal birth with an aim to generate a framework of good practice for information provision.

METHODS

Transcripts of in-depth interviews with women participants (n = 25), with recruiting midwives (n = 6) and recruitment discussions between midwives and women (n = 21), accepting or declining participation, were coded and interpreted using thematic analysis and content analysis to investigate what was helpful to women and what could be improved.

RESULTS

Recruiting women to intrapartum research is complicated by factors that impact on women's understanding and decision-making. Three key themes were derived from the data: (i) a woman-centred recruitment process, (ii) optimising the recruitment discussion and (iii) making a decision for two.

CONCLUSION

Despite evidence from the literature that women would like information provision and the research discussion to take place in the antenatal period, intrapartum studies still vary in the recruitment processes they offer women. Particularly concerning is that some women are given information for the first time whilst in labour, when they are known to feel particularly vulnerable, and contextual factors may influence decision-making; therefore, we propose a framework for good practice for information provision for research involving interventions initiated in the intrapartum period as a woman centred, and acceptable model of recruitment, which addresses the concerns of women and midwives and facilitates fair inclusion into intrapartum trials.

TRIAL REGISTRATION

ISRCTN. This qualitative research was undertaken as part of the ASSIST II Trial (trial registration number: ISRCTN38829082. Prospectively registered on 26/06/2019).

Interventions to reintroduce or increase assisted vaginal births: a systematic review of the literature

OBJECTIVE

To synthesise the evidence from studies that implemented interventions to increase/reintroduce the use of assisted vaginal births (AVB).

DESIGN

Systematic review.

ELIGIBILITY CRITERIA

We included experimental, semi-experimental and observational studies that reported any intervention to reintroduce/increase AVB use.

DATA SOURCES

We searched PubMed, EMBASE, CINAHL, LILACS, Scopus, Cochrane, WHO Library, Web of Science, ClinicalTrials.gov and WHO.int/ictrp through September 2021.

RISK OF BIAS

For trials, we used the Cochrane Effective Practice and Organisation of Care tool; for other designs we used Risk of Bias for Non-Randomised Studies of Interventions.

DATA EXTRACTION AND SYNTHESIS

Due to heterogeneity in interventions, we did not conduct meta-analyses. We present data descriptively, grouping studies according to settings: high-income countries (HICs) or low/middle-income countries (LMICs). We classified direction of intervention effects as (a) statistically significant increase or decrease, (b) no statistically significant change or (c) statistical significance not reported in primary study. We provide qualitative syntheses of the main barriers and enablers for success of the intervention.

RESULTS

We included 16 studies (10 from LMICs), mostly of low or moderate methodological quality, which described interventions with various components (eg, didactic sessions, simulation, hands-on training, guidelines, audit/feedback). All HICs studies described isolated initiatives to increase AVB use; 9/10 LMIC studies tested initiatives to increase AVB use as part of larger multicomponent interventions to improve maternal/perinatal healthcare. No study assessed women's views or designed interventions using behavioural theories. Overall, interventions were less successful in LMICs than in HICs. Increase in AVB use was not associated with significant increase in adverse maternal or perinatal outcomes. The main barriers to the successful implementation of the initiatives were related to staff and hospital environment.

CONCLUSIONS

There is insufficient evidence to indicate which intervention, or combination of interventions, is more effective to safely increase AVB use. More research is needed, especially in LMICs, including studies that design interventions taking into account theories of behaviour change.

PROSPERO REGISTRATION NUMBER

CRD42020215224.

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.

Outcomes of the novel Odon Device in indicated operative vaginal birth

BACKGROUND

No new method of assisting vaginal birth has been introduced into clinical practice since the development of the vacuum extractor in the 1950s. The Odon Device is a new device that employs a circumferential air cuff over the fetal head to assist birth. In this study, the Odon Device has been used to assist vaginal birth for standard clinical indications.

OBJECTIVE

This study aimed to investigate the clinical impact, safety, and acceptability of the Odon Device to women, their babies, and clinicians and to assess the feasibility of recruiting women to an interventional intrapartum research study.

STUDY DESIGN

This is a nonrandomized, single-arm interventional feasibility study of the Odon Device for operative vaginal birth undertaken in a single maternity unit: Southmead Hospital, Bristol, United Kingdom. The Odon Device was used to assist birth in 40 women who required the birth to be assisted for suspected fetal compromise and/or prolonged second stage of labor. The primary clinical outcome was the proportion of births successfully assisted with the Odon Device, and the primary feasibility outcome was the proportion of eligible women who were approached and who agreed to participate. Neonatal outcome data were reviewed at day 28, and maternal outcomes were investigated up to day 90.

RESULTS

Between October 2018 and January 2019, 298 of 384 approached, eligible women (77.6%) consented to participate. Of these women, 40 received the intervention-the use of the Odon Device. Birth was assisted in all cephalic (occiput anterior, occiput transverse, and occiput posterior) fetal positions, at all stations at or below the ischial spine and with or without regional analgesia. The Odon Device was effective in 19 of 40 cases (48%). Of the 40 births, 21 (52.5%) required additional assistance: 18 of 40 births (45%) were completed using nonrotational forceps, 1 of 40 births (3%) required rotational forceps, and 2 of 40 births (5%) required an emergency cesarean delivery. There was no serious maternal or neonatal adverse event related to the use of the device, and there was no serious adverse device effect. There were 4 devices (10%) that were ineffective because of a manufacturing fault. Furthermore, 39 of 40 women (98%) reported a high birth perception score. All practitioners were able to use the device as intended, although some steps in using the device were reported to be easier to perform (setup and deflation of air chamber) than others (application of the device and withdrawal of the applicator).

CONCLUSION

Recruitment to an interventional study of a new device for operative vaginal birth was feasible; 78% of eligible women were willing to participate, often expressing an aspiration for an alternative to forceps and vacuum. The success rate of the Odon Device was lower than reported success rates of vacuum and forceps; however, in this study, the device had been used to assist birth for standard clinical indications. There was no significant maternal or neonatal safety concern associated with the use of the device, although the number of births studied was small. Further feasibility study to establish iterative changes to the device, technique, and clinical indications is necessary.