Work package 1

Development of the Paramedic Acute Stroke Treatment Assessment

Material throughout this section has been reproduced with permission from Flynn et al.29 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The text below includes minor additions and formatting changes to the original text.

Systematic literature review

The completed review has been published.29

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant protocol30 was registered online as PROSPERO CRD42014010785.

To develop an enhanced paramedic assessment capable of supporting hospital thrombolysis of appropriately selected stroke patients, it was first necessary to understand challenges and successes reported during pre-hospital roles for any condition with known time-sensitive outcomes (i.e. trauma, myocardial infarction and stroke).

Therefore, an electronic search of published literature (from January 1990 to September 2016) was conducted across eight bibliographic databases that focused on (1) generic or specific structured handovers between ambulance and hospital personnel and (2) paramedic-initiated care processes at handover or post handover.

A narrative review of 36 studies shortlisted at the full-text stage indicated that (1) enhanced paramedic skills might supplement handover information as there would be a greater shared understanding of what information is important for the receiving medical team; (2) structured handover tools and feedback on performance can improve clinical communication during emergency transfer of patient care; and (3) enhanced paramedic roles following arrival at hospital were limited to ‘direct transportation’ of patients to imaging/specialist care facilities, and there were no examples of paramedics continuing to assist with patient care after handover. No descriptions were identified for pre-hospital thrombolysis-specific information collection tools or stroke-specific handover formats, but the review provided general support for the development of an enhanced paramedic role containing these elements.

Stakeholder engagement

To develop an intervention that was likely to be acceptable and feasible within UK ambulance and stroke services, relevant stakeholders were formally engaged in the design process. Fifteen focus groups and interviews were undertaken over the first 12 months of the programme in north-east England, north-west England and Wales, involving patient representatives (n = 20) and health-care professionals (n = 103), comprising paramedics and ED and HASU clinicians.31 Digital recordings were transcribed, anonymised and analysed using open and then focused coding with constant comparison.32,33 During four iterative rounds of data collection, themes were developed to understand barriers to and facilitators of the adoption of the paramedic intervention and the developing enhanced role/PASTA pathway material was amended accordingly.

In summary, paramedics, hospital clinicians and patients welcomed the use of enhanced skills during pre-hospital stroke assessment. Paramedics believed that they were capable of undertaking more detailed clinical assessments aimed at thrombolysis eligibility, but were unsure if their experience and skills would be recognised by hospital teams. Both professional groups strongly supported the use of a standardised handover format to enable new skills to be more effective and minimise the possibility of thrombolysis potential not being recognised by hospital triage staff receiving the patient. To encourage a joint working approach, there was general support for paramedics providing reminders about key time targets for brain imaging and treatment administration during handover.

All participants were uncertain about the feasibility of paramedics spending extra time in the hospital to assist the clinical team because of the wider implications for ambulance service response times. However, as there could be times when few hospital staff were available for initial care processes post handover, they agreed that it may be beneficial to assist with practical tasks as part of the intervention for up to 15 minutes (the standard service target interval between ambulance handover and departure). There was no system in place for paramedics to routinely receive feedback about their assessment process, but all professional groups were interested in the evidence showing that simple individual feedback could improve pre-hospital stroke care quality,17 and were enthusiastic for this to be incorporated.

During the fourth round of interviews, there were no additional changes to the proposed PASTA pathway or concerns from public representatives, and the Programme Steering Committee agreed that WP1 should progress towards delivery of the main trial.

The Paramedic Acute Stroke Treatment Assessment intervention

The PASTA pathway consisted of the following components (Figure 1):

1. Information – the paramedic seeks additional information at the scene, which is routinely considered during thrombolysis treatment decisions but typically is not obtained until after hospital admission (e.g. prescription of anticoagulant medication).
2. Pre-notification – although this is an expected component of standard care, the PASTA paramedics were specifically reminded to pre-alert the destination hospital.
3. Handover – on arrival at the hospital, the paramedic provided a standardised handover of stroke-specific details to the hospital team, including FAST, onset time, patient alertness as measured using the Alert, Verbal, Pain, Unresponsive (AVPU) scale34 and PASTA information.
4. Scan – if the computed tomography (CT) scanner was immediately available, the paramedic assisted with patient transfer to radiology.
5. Assist – up until 15 minutes after arrival, the paramedic undertook the following tasks as required: insertion of an intravenous cannula, obtaining the patient’s weight and repetition/clarification of clinical information for the arriving stroke team members.
6. Checklist – at 15  minutes after handover, the paramedic asked a member of the hospital team to confirm progress with key tasks (e.g. status of the scan request).
7. Feedback – the paramedic requested feedback from a hospital clinician about the accuracy of their provisional stroke diagnosis and onset time estimation.

FIGURE 1 The PASTA pathway intervention. FASTA PASTA CT, Face, Arm, Speech, Time, Alertness Plus Anticoagulants Surgery TIA Assistance Communication Targets; TIA, transient ischaemic attack. (Figure not reproduced here; see the original article.)

Examination of the Paramedic Acute Stroke Treatment Assessment pathway intervention clinical effectiveness: a cluster randomised trial

The published study protocol35 and the main study report36 have been published.

Material throughout this section has been reproduced with permission from Price et al.35 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The text below includes minor additions and formatting changes to the original text.

Material throughout this section has been reproduced with permission from Flynn et al.36 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 1.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/1.0. The text below includes minor additions and formatting changes to the original text.

The PASTA trial objectives were to:

• determine whether or not the PASTA pathway increased the proportion of patients receiving thrombolysis (the primary outcome)
• describe the impact of the PASTA pathway on key time intervals during delivery of care
• describe the number and subsequent diagnoses of suspected stroke patients who travelled to the hospital with a study paramedic but, following assessment at hospital, were not given a diagnosis of stroke (‘stroke mimics’).

Methods

A pragmatic multicentre cluster randomised controlled trial (RCT) design was chosen to reduce contamination of standard care by the intervention and avoid potential delays in care due to individual randomisation. Ethics approval was granted by the National Research Ethics Committee North East – Newcastle and North Tyneside 1 (reference 15/NE/0309).

The study was hosted by three ambulance services (i.e. north-east England, north-west England and Wales) with similar clinical pathways for standard care that reflected national clinical guidelines.10 These served 15 study hospital sites. Important acute activity and workforce characteristics are shown in Appendix 1, Table 6. Clusters were individual paramedics based within pre-randomised ambulance stations stratified by service, size and distance of station from the nearest study hospital. Paramedics who were based at stations randomised to the PASTA trial only became involved following successful completion of study-specific training (i.e. an online video and knowledge assessment). Paramedics based at standard care stations were simply informed that their clinical record entries would be supporting a study of pre-hospital assessment. Patients received the PASTA intervention or standard care according to which paramedic attended to them. Participating hospitals were not randomised and received both PASTA and standard care patients.

Participants

Patients were identified and recruited after completion of the thrombolysis assessment in participating hospitals if the following criteria were met:

• they travelled to hospital with a study paramedic
• they were aged ≥ 18 years
• they received a diagnosis of stroke from a hospital specialist
• they were within 4 hours of stroke onset (onset time determined by the hospital stroke team) when assessed by the study paramedic.

Intervention

Trained paramedics were requested to provide the PASTA pathway intervention (see Figure 1) to patients who they suspected were suffering a stroke and were within 4 hours of symptom onset. Initial paramedic stroke identification processes were unchanged. A study-specific ambulance data collection form was completed to record delivery of the different PASTA components. The patients attended by paramedics who were randomised to the standard care group received routine assessment and treatment.10

Outcome measures

The primary outcome was the proportion of patients receiving thrombolysis. The secondary outcomes included key time intervals during assessment and thrombolysis treatment, stroke severity 24 hours after thrombolysis [as measured on the National Institutes of Health Stroke Scale (NIHSS)],37 delivery of other components of acute care, day 90 death or dependency (mRS) score38,39 and complications after thrombolysis.40

Statistical analysis

Based on the effects reported by previous studies and our eligibility criteria, the sample size estimation considered that a change from 43% to 53% of study-eligible patients receiving thrombolysis would be clinically important. At 90% power, a 5% significance, an average cluster size (patients per paramedic) of five patients, an intracluster correlation coefficient of 0.02, an imbalance of two control patients per intervention patient (reflecting delays in the PASTA training uptake) and attrition of 1%, it was calculated that 1297 patients were required (standard care, n = 865; PASTA intervention, n = 432). However, the study protocol allowed for the final recruitment target to be kept under review and adjusted to reflect any changes in the underlying assumptions. The final required number of patients was 1149 based on a cluster size of three and a standard care-to-PASTA group imbalance of 8 : 5 patients.

Analysis was by ‘treatment allocated’ (i.e. the study group allocation of the station base for the attending paramedic). Imputation was used for missing NIHSS scores and day 90 mRS scores.

The primary analysis used logistic regression allowing for clustering by paramedic, with adjustment for clinically important and statistically significant covariates and factors to estimate an adjusted odds ratio (aOR) for the proportion of all patients receiving thrombolysis. The mRS was dichotomised into ‘favourable outcome’ (mRS score 0–2) or ‘poor outcome’ (mRS score 3–6) and an aOR of a ‘poor outcome’ was calculated. Other comparisons used odds ratios (ORs) by logistic regression and t-tests as appropriate. Cox proportional hazard regression estimated a hazard ratio for the combined impact of the intervention on thrombolysis and time to treatment since the emergency call.

A post hoc analysis considered whether or not routine hospital specialist availability for thrombolysis decision-making had any bearing on the treatment received in each study group. Workforce information reported in the 2016 Sentinel Stroke National Audit Programme (SSNAP) Acute Organisational Audit6 was used to categorise hospitals as compliant or non-compliant with the current national standard regarding hospital provision of a specialist thrombolysis service [i.e. there should be a minimum of six specialists trained in emergency stroke care providing a continuous rota without input from non-specialists, so that all treatment decisions are made by a stroke specialist (see Appendix 1, Table 6)].

Results

At 62 PASTA stations, 453 of 817 (55%) paramedics completed training. At 59 standard care stations, 700 of 723 (97%) paramedics agreed to assist. Between 10 December 2015 and 31 July 2018, 11,478 stroke patients travelling by ambulance were screened, 1391 fulfilled the eligibility criteria and were approached, and 1214 patients were enrolled. Of these, 500 were assessed by 242 PASTA paramedics (2.1 patients per paramedic) and 714 were assessed by 355 standard care paramedics (2.0 patients per paramedic). The follow-up is shown as per Consolidated Standards of Reporting Trials (CONSORT) reporting recommendations in Figure 2. Primary outcome data were available for all patients.

FIGURE 2 Trial profile. a, Eight paramedics allocated to standard care completed the PASTA training during the study. (Figure not reproduced here; see the original article.)

Demographic and clinical characteristics were very similar in the two study groups for all patients (see Appendix 1, Table 7). The mean age was 74.7 [standard deviation (SD) 13.2] years, women comprised 48% of the patient group and the median/mean admission NIHSS score was 9.0/11.4. Appendix 1, Table 8, shows the demographics and clinical characteristics according to the study group and receipt of thrombolysis.

The PASTA paramedics took an average of 13.4 minutes longer [95% confidence interval (CI) 9.4 to 17.4 minutes longer; p < 0.001] than the standard care paramedics to complete patient care episodes (i.e. ‘clear’ a patient), mainly because an additional 8.8 minutes was spent in the hospital (95% CI 6.5 to 11.0 additional minutes; p < 0.001). There was no significant difference between the groups for paramedic time spent on scene (PASTA intervention, 26.0 minutes; standard care, 24.2 minutes; difference 1.61 minutes, 95% CI –0.2 to 3.4; p = 0.08). There was no evidence of other differences between time intervals (see Appendix 1, Table 9).

There was no significant difference in the proportion of patients who received thrombolysis (Table 1) in the PASTA [197/500 (39.4%)] and standard care groups [319/714 (44.7%)], but there was a possible trend in the opposite direction to that of the anticipated intervention effect (aOR 0.81, 95% CI 0.61 to 1.08; p = 0.15; intracluster correlation coefficient 0.00). Among thrombolysis-treated patients, a PASTA paramedic assessment to assign a patient to thrombolysis was longer by an average of 8.5 minutes (95% CI 2.1 to 13.9 minutes longer; p = 0.01) than that of a standard care paramedic. The Cox regression analysis of time from the 999 call to treatment for the PASTA intervention group compared with standard care group reported an adjusted hazard ratio of 0.85 (95% CI 0.71 to 1.02; coefficient –0.17; p = 0.07), indicating that thrombolysis in the PASTA intervention group was less likely at any time point after the start of the emergency care pathway. After thrombolysis, there were no significant differences evident between groups for reduction in stroke severity or any treatment complication, but the number of events was small (see Table 1). No evidence for significant differences was observed for other individual acute care processes delivered to all patients (see Appendix 1, Table 10).

At day 90, there was no significant difference between groups for mortality [the PASTA intervention, 140/499 (28.1%); standard care, 199/712 (27.9%); OR 1.00 (95% CI 0.78 to 1.30); p = 0.97)]. Figure 3 shows the distribution of mRS score values at day 90. Although the CIs were wide enough to include clinically important differences favouring either group, there was an unexpected non-significant trend towards fewer poor outcomes (i.e. a mRS score ≥ 3) at day 90 among the PASTA intervention patients [PASTA intervention, 313/489 (64.0%); standard care, 461/690 (66.8%); aOR 0.86 (95% CI 0.60 to 1.2); p = 0.39], which was also seen among those who received thrombolysis [PASTA intervention, 108/193 (56.0%); standard care, 191/312 (61.2%); aOR 0.78 (95% CI 0.47 to 1.30); p = 0.34].

FIGURE 3 Distribution of day 90 mRS scores for all patients. (Figure not reproduced here; see the original article.)

Similar day 90 mRS score distributions for thrombolysis and non-thrombolysis groups are shown in Appendix 1, Figures 14 and 15. The serious adverse events were recorded from 81 PASTA patients (16%; total of 94 events) and 136 standard care patients (19%; total of 161 events). None of the serious adverse events had a causal link to the study intervention.

Eight hospitals were not fully compliant with the national standard for local specialist availability (see Appendix 1, Table 6). In the post hoc analysis, these non-compliant services showed a statistically significant 9.8% absolute reduction in the PASTA thrombolysis treatment rate compared with the standard care thrombolysis treatment rate [PASTA intervention, 99/276 (35.9%); standard care, 105/230 (45.7%); unadjusted OR 0.67 (95% CI 0.47 to 0.95); p = 0.03], whereas there was no difference at the seven compliant hospitals [PASTA intervention, 98/224 (43.8%); standard care, 214/484 (44.2%); unadjusted OR 0.98 (95% CI 0.71 to 1.35); p = 0.91].

Study-specific ambulance data collection forms recording delivery of the PASTA pathway were located for 227 out of 500 (45.5%) intervention patients. Use of the structured handover was recorded for 59.0% and use of the individual components of the checklist ranged from 57.3% to 90.3%. Full data are shown in Appendix 1, Table 11.

Although patients with symptoms mimicking stroke were not enrolled in the trial, hospital research support staff recorded that 1596 such patients were transferred by a study paramedic. The most common non-stroke diagnoses were transient ischaemic attack (TIA) (34.5%), headache/neurological (13.1%), epilepsy/seizure (10.3%), infection/sepsis (9.0%), syncope/circulation (6.1%), functional (4.1%), brain imaging diagnosis [e.g. tumour (3.5%)] and metabolic disturbances (3.3%).

Discussion

This multisite pragmatic trial showed that a paramedic-initiated thrombolysis-focused emergency stroke assessment that extended beyond hospital handover did not increase thrombolysis rates. Instead, there was a trend towards less thrombolysis administration. Although there was a longer initial paramedic assessment process, it is unlikely that the PASTA intervention resulted in patients simply ‘timing out’ of treatment as this was, proportionally, a minor extension of the whole emergency pathway, and the Cox regression analysis indicated that intervention thrombolysis was probably less likely at any time point since the emergency call.

It may be surprising that these results show that the PASTA pathway did not improve thrombolysis delivery when simpler pre-hospital interventions have increased treatment rates (e.g. raising the ambulance priority level for suspected stroke)16 and reduced hospital treatment delays (e.g. pre-notification),41 but the service context of each report is likely to be relevant. Previously, additional thrombolysis activity was observed at four out of six US centres following a multilevel intervention comprising public awareness activities, a paramedic symptom checklist and competitive benchmarking.15 The two unchanged centres had high baseline treatment rates and may have already achieved optimal performance. A similar ceiling effect may explain the lack of effect among the PASTA sites, which were already established thrombolysis providers. A multisite Scandinavian trial16 randomised 942 suspected stroke/TIA patients to a higher and standard response level after multidisciplinary training. The study reported a thrombolysis rate of 24%, compared with 10% among controls. Like the PASTA intervention, there was no significant change in door-to-needle time, suggesting that delays following admission relate to logistical factors such as scan capacity, image reporting and specialist availability.

Despite the intervention group showing a surprising trend towards fewer thrombolysis treatments, outcomes were not adversely affected and there was a counter-intuitive trend towards better health. If indicative of a genuine effect, one possible hypothesis is an influence on case selection, that is structured communication of directly relevant and timely information by the PASTA paramedics might increase clinician confidence about withholding treatment when there is borderline benefit, higher than average risk or uncertainty about key details, such as onset time. The post hoc analysis showed that intervention group thrombolysis was significantly less likely across services with specialist availability below the level recommended by national guidelines.6 Relatively inexperienced clinicians under time pressure may tend towards overtreatment rather than undertreatment of borderline cases, which could be moderated by the PASTA handover and/or checklist, whereas services with greater specialist continuity may already apply a more systematic approach to case selection. Being an unexpected finding, we had not collected the required data describing clinical and radiological quality of individual treatment decisions to confirm this hypothesis. However, previous ED studies have reported that, typically, less than half of pertinent items of information are shared during standard handover of mixed patient groups,42 with significant variation due to the level of experience of the clinicians involved.18,43 The relevance and clarity of handover can be improved by introduction of simple generic formats19,29 while multidisciplinary team checklists make care safer through clarification of information and reinforcement of important standards.20,21

The distribution of mimic conditions observed was typical of previous ambulance studies and clinical reports,44 providing reassurance that the suspected stroke cohort underpinning the trial was representative of the wider clinical population.

Examination of the Paramedic Acute Stroke Treatment Assessment pathway intervention cost-effectiveness

The main study report has been published.45

Material throughout this section has been reproduced with permission from Bhattarai et al.45 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The text below includes minor additions and formatting changes to the original text.

A within-trial health economic analysis estimated the cost-effectiveness of the PASTA intervention, compared with standard care, over 90 days of follow-up. As the trial post hoc analysis showed that thrombolysis varied according to specialist availability, a sensitivity analysis was undertaken to determine if costs and cost-effectiveness varied by site-level specialist availability. The economic evaluation was reported following best practice guidelines conforming to the Consolidated Health Economic Evaluation Reporting Standards (CHEERS).

Methods

Outcomes were QALYs and cost per participant reported in 2017/18 Great British pounds from an NHS and social service perspective. QALYs were based on health utility scores generated from mapping discharge and day 90 mRS scores to EuroQol-5 Dimensions, three-level version, values.46 These were converted into QALYs using the area under the curve method, controlling for pre-stroke disability, age and sex. Costs were derived from prospectively captured resource utilisation data, including paramedic time, acute medical treatments, bed-days, post-discharge rehabilitation, social services involvement (paid carers at home and in social care settings) and hospital re-admissions. Standard unit costs were used in calculations.47,48 As the time horizon was 90 days, discounting of costs and outcomes was not required.

A complete-case data set and an imputed data set were analysed. Missing cost and utility data were imputed using predictive mean matching within the multiple imputation generated by chained equations. Generalised linear model regressions with gamma family link function estimated marginal costs while controlling for age, sex and pre-stroke disability clustered by site.49 Stochastic sensitivity analysis used non-parametric bootstrapping to quantify and explore the impact of statistical imprecision surrounding the point estimates of costs, QALYs and cost-effectiveness. The likelihood that the PASTA intervention would be cost-effective, compared with standard care, was reported over a range of willingness-to-pay (WTP) values.

Results

The unadjusted differences for complete-case mean mRS scores, utility, QALYs and total cost estimates between the PASTA intervention and standard care are shown in Appendix 2, Table 12. Over the 90-day follow-up period, there was no evidence of QALY differences between groups in either complete-case (0.007, 95% CI –0.003 to 0.018) or imputed data (0.005, 95% CI –0.004 to 0.015) (Table 2). There were lower total costs in the PASTA intervention group for both complete-case (–£1473, 95% CI –£2736 to –£219) and imputed data sets (–£1086, 95% CI –£2236 to –£13).

Detailed descriptive costs from the complete-case data set are shown in Appendix 2, Table 13. Although there was a greater mean cost for paramedic training time and longer patient episode duration in the PASTA intervention group than in the standard care group, there were savings from less use of thrombolysis medication, reductions in length of hospital stay and reductions in the duration of rehabilitation and provision of social care support. The costs for other acute stroke treatments were slightly higher among the PASTA patients.

A plot of bootstrapped differences in mean costs and QALYs for the imputed data set showed that for most iterations (91.3%), the PASTA intervention was less costly and more effective than standard care (Figure 4).

FIGURE 4 Cost-effectiveness plane for imputed data. (Figure not reproduced here; see the original article.)

Over the range of values for society’s WTP for 1 QALY, there was a > 97.5% chance that the PASTA intervention group would be considered cost-effective (see Appendix 2, Figure 16).

The post hoc economic sensitivity analysis results are shown in Appendix 2, Table 14. The seven compliant hospitals where there was no evidence of a thrombolysis rate difference between the PASTA and standard care groups showed no evidence of a difference in QALYs (0.005, 95% CI –0.008 to 0.018) or costs (–£423, 95% CI –£2220 to £1362). The eight non-compliant hospitals that together had a thrombolysis reduction in the PASTA intervention group provided no evidence of a difference in QALYs (0.009, 95% CI –0.008 to 0.025), but costs were lower for the PASTA patients than for standard care patients (–£2952, 95% CI –£4988 to –£917)]. Cost-effectiveness planes for the compliant and non-compliant hospitals are shown in Appendix 2, Figures 17 and 18.

Discussion

Although the paramedic-led thrombolysis-focused emergency stroke assessment used in the PASTA trial did not increase thrombolysis rates, the economic evaluation showed a cost saving associated with the PASTA intervention group. The QALY differences were, on average, small and there was no evidence of differences, but, overall, there was a very high chance that the PASTA intervention would be cost-effective across all WTP threshold values.

Although it is not surprising that fewer thrombolysis treatments resulted in lower costs, it was unexpected to observe the PASTA intervention group savings in other aspects of care, including length of hospital stay, rehabilitation and social care. Although these data require cautious interpretation, patients with better health following emergency assessment would require lower costs for each of these resources in turn.50 However, it is important to acknowledge that the health difference was non-significant, small and short term.

Although the economic results are not intuitive, previous triallists have proposed that costs of care can be more sensitive indicators of all consequences (expected and unexpected) of a complex intervention in a pragmatic trial than a pre-chosen primary end point that focuses on one anticipated impact only.51 This proposal is consistent with the idea that the PASTA intervention could have a mixed effect on patient care.

In the post hoc analysis, a reduction in costs up until 90 days was particularly evident for the PASTA patients across services with specialist availability below the level recommended by national guidelines. This is consistent with the earlier hypothesis (see Examination of the Paramedic Acute Stroke Treatment Assessment pathway intervention clinical effectiveness: a cluster randomised trial, Discussion) that relative inexperience normally leads to overtreatment rather than undertreatment of borderline cases by non-specialists. Better clinical acumen would not only save costs by preventing futile thrombolysis, but could also avoid a longer length of stay associated with essential monitoring after treatment and rehabilitation following harmful complications.

Impact of the Paramedic Acute Stroke Treatment Assessment intervention on ambulance response times

During funding of the programme and development of the PASTA intervention (see Development of the Paramedic Acute Stroke Treatment Assessment, Stakeholder engagement), concerns were raised by reviewers and ambulance personnel regarding any negative impact from the additional time that intervention paramedics could spend in the hospital post handover, rather than becoming ‘clear’ again for another emergency call. To identify any effect on ambulance service responsiveness as a result of the PASTA intervention delivery, we undertook a retrospective observational study of the North East Ambulance Service (NEAS)’s emergency performance in parallel with the PASTA trial.

Methods

The NEAS was selected because all hospitals within the boundary of the service were trial sites, and the likelihood of finding any effect would, therefore, be higher than in regions with only partial coverage (i.e. north-west England and Wales). Until October 2017, for each patient consented to the trial, NEAS provided audit compliance information regarding any ‘Red 1’ (suspected cardiac arrest requiring an 8-minute response) and ‘Red 2’ calls (any other serious emergency requiring an 8-minute response time) occurring in the service 1 hour before the trial patient was attended by a study paramedic, and hourly afterwards for the next 3 hours. This allowed examination of whether or not the PASTA intervention had a wider impact on the service response by comparing, between the PASTA and standard groups, whether or not national audit targets for any parallel Red 1 and Red 2 calls were achieved (i.e. an appropriate ambulance vehicle arrived for those patients within 8 minutes of the 999 call). It was not possible to continue this evaluation after October 2017 as national ambulance metrics changed and data were no longer available.

Results

Between December 2015 and October 2017 (i.e. for 23 months), in the 1 hour before and 3 hours after any enrolled trial patient being attended by a study paramedic, there were a total of 831 and 2533 Red 1 calls, and 12,155 and 38,708 Red 2 calls, respectively (see Appendix 3, Tables 15 and 16). The average compliance across all patients was 68.7% for Red 1 and 61.1% for Red 2. As shown in Figures 5 and 6, after removal of hours when Red calls did not occur, there were no significant differences between the PASTA and standard care groups in the proportion of compliant Red 1 or Red 2 calls achieved by the service at any hourly time point in relation to an enrolled patient being attended by a study paramedic.

FIGURE 5 Proportion of compliant Red 1 ambulance responses in the 1 hour before and 3 hours after a study patient was attended by a paramedic. The dark blue circles show the standard care and the light blue diamonds show the PASTA study groups. (Figure not reproduced here; see the original article.)

FIGURE 6 Proportion of compliant Red 2 ambulance responses in the 1 hour before and 3 hours after a study patient was attended by a paramedic. The dark blue circles show the standard care and the light blue diamonds show the PASTA study groups. (Figure not reproduced here; see the original article.)

Discussion

The results provide reassurance that, despite engaging paramedics for an average of 13.4 minutes longer with trial patients, the PASTA intervention did not cause decompensation of the ambulance service’s ability to respond to its highest priority calls. This is not surprising as this time interval fell within the 15 minutes’ tolerance for ambulance departure after hospital handover, and suspected stroke is a relatively small proportion (approximately 3%) of ambulance service activity, so should not create a service-wide capacity issue. It is important to recognise that these data reflect calls related to patients who were consented to the trial and not all suspected stroke patients who were attended by study paramedics, but the results support the ongoing hosting of stroke research by ambulance services.

Process evaluation of the Paramedic Acute Stroke Treatment Assessment intervention

The main study report has been published.52

Material throughout this section has been reproduced with permission from Lally et al.52 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: https://creativecommons.org/licenses/by/4.0/. The text below includes minor additions and formatting changes to the original text.

There were three groups involved in a process evaluation that intended to describe the acceptability and feasibility of the PASTA pathway in the clinical setting: intervention paramedics, hospital clinicians and intervention group patients.

Methods

Participants were invited to semistructured interviews (in person or over the telephone). Hospital research support staff sought medically stable patients who were attended by a NEAS intervention paramedic within the last 7 days. Interviews were audio-recorded, anonymised and transcribed. Data collection and analysis was an iterative process, following the combined principles of the constant comparative32 and thematic analysis.33 Two researchers coded transcripts independently, which were then compared and further analysed during data sessions. Approval was given by the National Health Service Research Ethics Committee Newcastle and North Tyneside (reference 15/NE/0309).

Results: intervention paramedics

In total, 26 interviews were conducted across the three ambulance services (north-east England, n = 11; north-west England, n = 10; and Wales, n = 5). Participants’ length of service ranged from 14 months to 27 years, with qualifications up to postgraduate degree level.

Iterative data analysis identified four key themes, which reflected paramedics’ experiences at different stages of the intervention care pathway:

1. Enhanced assessment at scene – paramedics reported that the PASTA intervention complemented their skill set and confidence, and the trial training allowed them to feel well prepared. Illustrative quotations are shown in Appendix 4, Box 1.
2. The pre-alert to the hospital – when local standard care pathways permitted conveyance of additional patient details, pre-notification contained more detailed and appropriate information as a result of the PASTA enhanced assessment. Illustrative quotations are shown in Appendix 4, Box 2.
3. Handover to hospital team – the standard ‘scripted’ format for handover of thrombolysis-specific information was viewed as the primary benefit of the PASTA pathway. Paramedics felt more confident during communication with the hospital team, and felt that they were less likely to forget important details. Illustrative quotations are shown in Appendix 4, Box 3.
4. Assisting in the hospital and feedback – owing to traditional professional boundaries, paramedics found these aspects harder to achieve, although feedback from the clinical team was valued when available. Illustrative quotations are shown in Appendix 4, Box 4.

Results: hospital clinicians

Seven focus groups and one telephone interview were conducted across the three study regions. A total of 25 staff participated, including stroke specialist nurses, ED nurses and stroke consultants.

The following main themes were identified, also reflecting key stages of the pathway:

1. Enhanced paramedic role – hospital staff perceived that paramedics generally seemed to enjoy the role and receiving feedback (see Appendix 4, Box 5: quotations 1 and 2). They reported that there were not as many paramedics trained as they had expected.
2. Handover value – staff who had directly experienced the handover viewed it positively. They reported that the PASTA paramedics required fewer prompts from the stroke or ED team to get the details they needed, and the information was provided in the appropriate order (see Appendix 4, Box 5: quotations 3 and 4).
3. Post-handover uncertainty – in a few settings, it was valued that the PASTA paramedics assisted with practical tasks after handover, such as taking the patient for urgent brain imaging, as this freed up the hospital staff to prepare for the possibility of thrombolysis treatment (see Appendix 4, Box 5: quotation 5). However, this assistance was not always required by the hospital staff or consistently offered by the paramedics, who may have found it difficult to initiate (see Appendix 4, Box 5: quotation 6). Even if extra assistance was not needed, feedback to paramedics was viewed positively (see Appendix 4, Box 5: quotation 7).

Results: intervention patients

Six patients (five male and one female) were interviewed, after which a decision was made by the TSC to stop further patient recruitment because of the limited information being obtained about the PASTA intervention. Some patients could not remember any specific details, and those who could provide an account of their admission to hospital could not recall any specific details of paramedic actions. This may reflect the nature of acute stroke on perception or memory and the emotional state of patients at the time, but it is also likely that patients had no prior knowledge of paramedic care processes that would have enabled them to identify any actions that were related to the intervention.

Discussion

Even though there was overlap with existing practice, participating paramedics and hospital staff valued the structure of the PASTA pathway. The pathway was considered to enhance paramedic confidence and shared care, although there was less value post handover because help was not always required and traditional boundaries were harder to overcome.

Strong support was expressed for the structured patient assessment and corresponding information handover. A review of 12 studies examining structured patient assessment frameworks found evidence of improved documentation,53 but no examples from pre-hospital care. The general need to improve emergency handover has been highlighted by a review of 21 studies, which identified concerns about communication in the chaotic ED environment, exacerbated by a lack of time and resources.18 More recently, there have been reports in support of structured generic handovers19 and a version for trauma care,54–56 but there have been no previous descriptions of a stroke-specific handover.29

On completion of the PASTA pathway checklist, paramedics welcomed the opportunity to receive immediate feedback, which hospital staff were happy to provide. Previous interviews with Canadian paramedics also found positive perceptions of feedback, but this was described as informal and opportunistic.57 Feedback to individual paramedics has been shown to encourage adherence to standard stroke care assessment, but was not in given real time and did not allow clarification by the recipient.17