Contributions to the literature
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This is the first independent robust implementation study of GAP (Growth Assessment Protocol); we identified concerns about costs and staffing resources required for GAP implementation.
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Ambivalence about the value of GAP also appeared to impact upon staff willingness to implement, emphasising the need for consistently articulated leadership support.
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Our research shows how use of routine clinical data within a trial can identify gaps in implementation and inform future implementation research.
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Further methodological research is required on the development of composite measures of implementation strength.
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This is one of the first process evaluations to use the context and implementation of complex interventions framework.
Background
Methods
Study design
Implementation outcome | Outcome source | Application to implementation of GAP | Data source |
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Context± | Semi-structured interviews with lead clinicians and frontline staff | ||
Fidelity | Steckler and Linnan (2002) [28] | Adherence to GAP provider training requirement that 75% of staff from each professional group (midwives, sonographers, obstetricians) were trained using both (i) face-to-face and (ii) e-learning methods | Staff training records from the GAP provider |
Degree of concordance to Perinatal Institute guideline assessed as follows: Low: partial or no inclusion of Perinatal Institute’s (PI) recommendations throughout the guidelines, affecting over half of the recommendations. Medium: Moderately concordant with partial or no inclusion of PI’s recommendations in less than half of the recommendations High: Very concordant with only occasional differences where PI’s recommendations were partially included | Local clinical guidelines on screening for foetal growth anomalies | ||
Proportion of women correctly risk stratified (according to GAP) | Review of the maternity records of 600 women who gave birth during the trial period (40 from each of December 2018, January and February 2019 in each cluster) | ||
Reach | Steckler and Linnan (2002) [28] | Proportion of women with a GAP-GROW chart in the notes | Maternity records review (see above) |
Dose delivered and received | Steckler and Linnan (2002) [28] | Proportion of low-risk women* who had at least the minimum expected fundal height measurements performed and plotted on the chart | Maternity records review (see above) |
Proportion of low-risk women* referred for growth scan when indicated | |||
Proportion of high-risk women* who had at least the minimum expected growth scans performed and plotted on the chart | |||
Implementation strength | Schellenberg et al. (2021) [30] | Combined assessment of fidelity, dose and reach | |
Acceptability | Proctor et al. (2011) [31] | Acceptability of GAP implementation from the perspectives of clinicians | Semi-structured interviews with lead clinicians and frontline staff |
Feasibility | Proctor et al. (2011) [31] | The degree to which GAP implementation is feasible, from the perspectives of interview participants |
Description of standard care
Description of the intervention and implementation strategy
Implementation process domains (CICI) | Intervention components | Implementation strategies |
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Decision to adopt | • Recruit sites | |
Planning and preparation | • Update the maternity unit’s foetal growth assessment guideline in line with guidance issued by the Perinatal Institute • Audit of baseline rates of detection of the SGA foetus • Trust protocol aligned with GAP | • Identify maternity unit’s GAP team and administration leads (midwife, sonographer, obstetric leads, information technology liaison for hardware and software) • Perinatal Institute convenes monthly meetings between nominated GAP leads from local sites to discuss implementation progress and challenges • Complete baseline audit of rate of SGA, referral for suspected SGA and confirmed SGA detection (3 months’ births) |
Initial implementation | • Annual whole-staff training on the intervention by both face-to-face and e-learning methods | • Selected staff to attend GAP ‘train the trainers’ workshop, led by the Perinatal Institute • Trainers to cascade both face-to-face and e-learning GAP training to 75% of staff from each professional group: midwives, sonographers and obstetricians • Perinatal Institute continues to meet monthly with GAP leads |
Full implementation (‘going live’) | • Risk stratification of pregnant women in early pregnancy into two strata according to whether women are at low or high risk of SGA, using the NHS-England risk-stratification decision tool [15] • Serial fundal height measurements for low-risk women, plotted onto a ‘gestation-related optimal weight’ (GROW) centile chart, which is customised by maternal height, weight, ethnicity and parity [32] • Serial foetal growth ultrasound for high-risk women, with the estimated foetal weight plotted onto the GROW chart • Protocols for the interpretation and onward management of plots on the GROW chart which deviate from the expected growth trajectory | • Use GAP SGA risk assessments and SGA management referrals from ‘go live’ date • Facilitate printing of GROW centile chart and incorporation into individual maternity notes • For low-risk women, begin plotting fundal height measurements onto GROW chart from 26 to 28 weeks every 2–3 weeks • For high-risk women, foetal growth ultrasound every 3 weeks from 26 to 28 weeks until the end of pregnancy • Raise awareness amongst staff of GAP with posters, emails, reminders and in-person visits by GAP leads and trainers to antenatal care settings • Liaise with PI about GAP queries |
Evaluation, reflection and sustainment | • Guidance on the conduct of missed case audit and investigation | • Undertake audit of missed FGR cases (10 cases 6 monthly or 1% of birth rate) |
Data collection
Measurement of implementation strength
Qualitative implementation data analysis
Ethical considerations
Results
Findings
Acceptability: GAP lead and frontline staff perspectives on the potential value and clinical effectiveness of GAP
I generally welcomed it, I was excited about it, I thought it was…a nice rigorous way of decision-making.(SC21, GAP Lead, Site 10)
Generally, I think the majority of us don’t really want to [implement GAP]. We don’t really understand why we are doing it.…(HP12, Frontline staff, Site 11)
I didn't welcome it. I was a bit sceptical of it and maybe this was influenced from speaking to some of my colleagues….(SC31, GAP Lead, Site 9).
Acceptability of GAP implementation: GAP lead and frontline staff perspectives
[GAP leads to identification of more large babies and therefore] lots of intervention that may not be warranted.(HP3, Frontline staff, Site 7)
I’d say probably half of the women are coming above the line... I just think a lot of women come up quite high on the chart and it can be quite worrying for them(HP91, Frontline staff, Site 10)
The sonographers were very uncomfortable with not allowing the AC [fetal abdominal circumference] to drive the decision around further scanning….…[they]…felt that they might get blamed if, you know, the EFW [estimated fetal weight] is normal but the AC is slightly dropping and they didn’t act accordingly(SC17, GAP lead, Site 11)
Feasibility of GAP implementation: GAP lead and frontline staff perspectives
We have a lot of patients who come and usually we are full, we are booked completely, and to fit the patient within three working days is very, very difficult. Sometimes we have to scan during our lunchtime which is not ideal at all but then otherwise we breach the time…(HP41, Frontline staff, Site 9)
Er, their [GAP] BMI [body mass index, referral point] is, er, lower than ours, so we would only refer if they were 35 and over. Just because all of our women…we’d just be referring everyone(SC20, GAP lead, Site 7)
…it’s just not feasible for myself and my colleague to train [hundreds of] midwives between the two of us, when we’re not being given any allocation of time…(SC06, GAP lead, Site 9)
We have had drop-ins where we get people to try and sit and do their online training. And I think that has been the biggest issue, as far as I know we’re still not at the level that we should’ve… had with the online training.(SC21, GAP lead, Site 10)
So we are using [ultrasound generated charts] in conjunction with the GAP charts still…at the moment, they are running alongside each other which at the beginning did generate some problems…(HP23, Frontline staff, Site 11)
…the [Trust] IT system doesn’t link in with the Perinatal Institute’s GAP GROW, which is possibly the case for a lot of people’s IT systems…So you end up with lots of bits of paper [laughs] because it’s a bit of a hybrid, and probably every trust has to work out their own little system for that.(SC04/SC07, GAP lead, Site 8)
Describing the context of implementation and how it interacts with the implementation process
How context affected early implementation
There were multiple triggers, some of them being our own local experiences in reviewing cases where there had been adverse outcomes…That was one trigger. Then the growth assessment guidelines from [RCOG]…was another trigger. Then the Saving Babies’ Lives processes also needed us to look at ways of streamlining our care. Those are the kind of things I would say made us choose [to adopt GAP].(SC12 and SC22, GAP lead, Site 8)
…our Trust is under pressure with finances, so they are cutting down everything. So, that is why the new management didn’t want to spend this additional [money] for the GAP programme. It’s not my decision, it’s a management decision.(SC1, Clinical lead, Site 13)
…the Research & Development department did try their best, but then when they saw there was no funding, they couldn’t see any value in [participating in the trial]…[but] we see the benefit, the benefit of the trial.(SC14, Clinical lead, Site 12)
Int: Did you find that there was anything that made it easier for you, or something that was supporting you to cascade training to your colleagues?I think the support that we got from [colleague 1] and also [colleague 2] was very, very helpful. And [colleague 1] was very visible to us and …very willing to answer a question…(HP5, Site 11)
Impact of context on ‘full implementation’
…our protocol has been historically –[for] 50 years, ever since ultrasound assessment has been [used], practice has been [to scan again in] four weeks, so bringing it down to three weeks …is a bit hard(SC22, GAP lead, Site 8)
…you know, [at] 36 weeks, and you measure 33 centimetres, your mind tells you, I have to scan this woman! [laughs] But the chart tells you, you don’t need to. So for the midwives it’s a bit of …you know, they have to really feel confident that actually yes, it’s working(SC25, GAP Lead, Site 10)
…there were babies being missed [before] and the outcomes were not good for those babies, so [GAP] definitely needed to be implemented.(HP74, Frontline staff, Site 7)
Measure of implementation strength
Fidelity
Site 7 | Site 8 | Site 9 | Site 10 | Site 11 | |||
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Fidelity | Degree of concordancea with Perinatal Institute guideline | Low | High | Medium | Medium | High | |
Proportion of staff trained within each professional group | Face-to-face target | > 75% | > 75% | > 75% | > 75% | > 75% | |
E-learning target | < 75% | < 75% | > 75% | < 75% | < 75% | ||
Proportion of women risk stratified according to GAP | 87.5% (105/120) | 78.6% (92/117) | 84.2% (105/121) | 83.2% (99/119) | 84.4% (98/116) | ||
Reach | Proportion of women with a GAP-GROW chart in the notes | 62.2% (74/119) | 98.3% (115/117) | 93.3% (131/121) | 96.6% (115/119) | 94.2% (113/120) | |
Dose | Proportion of low-risk women who had at least the minimum expected number of fundal height measurements performed and plotted on GROW | 8.2% (4/49) | 53.2% (42/79) | 34.4% (31/90) | 31.4% (22/70) | 18.1% (15/83) | |
Proportion of low-risk women referred for growth scan when definite plot deviation | 40.0% (4/10) | 79.2% (19/24) | 80.9% (17/21) | 66.7% (10/15) | 61.2% (19/31) | ||
Proportion of high-risk women who had at least the minimum expected number of growth scans performed and plotted on GROW | 0.0% (0/33) | 16.7% (8/48) | 2.9% (1/35) | 12.8% (6/47) | 5.3% (2/38) |
Site reference | |||||||
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Risk status (by GAP) | Site 7 | Site 8 | Site 9 | Site 10 | Site 11 | All | |
Agreement between GAP and clinician | High risk (n) | 32 | 24 | 21 | 32 | 24 | 133 |
Low risk (n) | 73 | 68 | 87 | 68 | 76 | 372 | |
Both n(%) | 105/120 (87.5%) | 92/117 (78.6%) | 108/121 (89.3%) | 100/117 (85.5%) | 100/120 (83.3%) | 505/595 (84.9%) | |
Clinician did not classify risk as recommended in GAP | High risk (n) | 9 | 13 | 9 | 3 | 14 | 48 |
Low risk (n) | 6 | 12 | 4 | 14 | 6 | 42 | |
Both n(%) | 15/120(12.5%) | 25/117 (21.4%) | 13/121 (10.7%) | 17/117 (14.5%) | 20/120 (16.7%) | 90/595 (15.1%) | |
If GAP classification is wrong, classified correctly as per local policy? | n(%) | 2/15 (13.3%) | 0/25 (0.0%) | 7/13 (53.8%) | 7/17 (41.2%) | 3/20 (15.0%) | 19/90 (21.1%) |
Reach and dose
Women with at least the minimum expected number of fundal height chart plots | ||
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Site identifier | Number | Percentage |
Site 7 (n = 49) | 4 | 8.2% |
Nulliparous (n = 25) | 3 | 12.0% |
Multiparous (n = 24) | 1 | 4.2% |
Site 8 (n = 79) | 42 | 53.2% |
Nulliparous (n = 43) | 28 | 65.1% |
Multiparous (n = 36) | 14 | 38.9% |
Site 9 (n = 90) | 31 | 34.4% |
Nulliparous (n = 55) | 22 | 40.0% |
Multiparous (n = 35) | 9 | 25.7% |
Site 10 (n = 70) | 22 | 31.4% |
Nulliparous (n = 43) | 15 | 34.9% |
Multiparous (n = 27) | 7 | 25.9% |
Site 11 (n = 83) | 15 | 18.1% |
Nulliparous (n = 36) | 9 | 25.0% |
Multiparous (n = 47) | 6 | 12.8% |
Total (n = 371) | 114 | 30.7% |
Nulliparous (n = 202) | 77 | 38.1%a |
Multiparous (n = 169) | 37 | 21.9%a |