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Evaluation of a novel vital sign device to reduce maternal mortality and morbidity in low-resource settings: a mixed method feasibility study for the CRADLE-3 trial

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Nicola Vousden, Elodie Lawley, Hannah L Nathan, Paul T Seed, Adrian Brown, Tafadzwa Muchengwa, Umesh Charantimath, Mrutyunjaya Bellad, Muchabayiwa Francis Gidiri, Shivaprasad Goudar, Lucy C Chappell, Jane Sandall, Andrew H Shennan, CRADLE Trial Collaborative Group

Original languageEnglish
Article number115
JournalBMC Pregnancy and Childbirth
Issue number1
Accepted/In press9 Apr 2018
Published27 Apr 2018


  • Evaluation of a novel_VOUSDEN_Accepted9April2018_GOLD VoR (CC BY)

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    © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

King's Authors


BACKGROUND: The CRADLE-3 trial is a stepped-wedge randomised controlled trial aiming to reduce maternal mortality and morbidity by implementing a novel vital sign device (CRADLE Vital Sign Alert) and training package into routine maternity care in 10 low-income sites. The MRC Guidance on complex interventions proposes that interventions and implementation strategies be shaped by early phase piloting and development work. We present the findings of a three-month mixed-methodology feasibility study for this trial, describe how this was informed by the MRC guidance and the study design was refined.

METHODS: The fidelity, dose, feasibility and acceptability of implementation and training materials were assessed in three representative non-trial sites (Zimbabwe, Ethiopia, India) using multiple-choice questionnaires, evaluation of clinical management (action log), healthcare provider (HCP) semi-structured interviews and focus groups 4-10 weeks after implementation. Simultaneously, the 10 sites included in the main trial (eight countries) collected primary outcome data to inform the power calculation and randomisation allocation and assess the feasibility of data collection.

RESULTS: The package was implemented with high fidelity (85% of HCP trained, n = 204). The questionnaires indicated a good understanding of device use with 75% of participants scoring > 75% (n = 97; 90% of those distributed). Action logs were inconsistently completed but indicated that the majority of HCP responded appropriately to abnormal results. From 18 HCP interviews and two focus groups it was widely reported that the intervention improved capacity to make clinical decisions, escalate care and make appropriate referrals. Nine of the ten main trial sites achieved ethical approval for pilot data collection. Intensive care was an inconsistent marker of morbidity and stroke an infrequent outcome and therefore they were removed from the main trial composite outcome. Tools and methods of data collection were optimized and event rates used to inform randomisation.

CONCLUSIONS: This feasibility study demonstrates that the components of the intervention were acceptable, methods of implementing were successful and the main trial design would be feasible. Qualitative work identified key moderators that informed the main trial process evaluation. Changes to the training package, implementation strategy, study design and processes were identified to refine the implementation in the main trial.

TRIAL REGISTRATION: ISRCTN41244132 ; Registered 24/11/2015.

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