Venous blood point-of-care testing (POCT) for paramedics in urgent and emergency care: protocol for a single-site feasibility study (POCTPara) (2024)

The COVID-19 pandemic placed the UK healthcare system under unprecedented pressure, and recovery will require whole-system investment in innovative, flexible and pragmatic solutions. Positioned at the heart of the healthcare system, ambulance services have been tasked with addressing avoidable hospital conveyance and reducing unnecessary emergency department and hospital attendances through the delivery of care closer to home. Having begun to implement models of care intended to increase ‘see and treat’ opportunities through greater numbers of senior clinical decision makers, emphasis has now been placed upon the use of remote clinical diagnostic tools and near-patient or point-of-care testing (POCT) to aid clinical decision making. In terms of POCT of blood samples obtained from patients in the pre-hospital setting, there is a paucity of evidence beyond its utility for measuring lactate and troponin in acute presentations such as sepsis, trauma and myocardial infarction, although potential exists for the analysis of a much wider panel of analytes beyond these isolated biomarkers. In addition, there is a relative dearth of evidence in respect of the practicalities of using POCT analysers in the pre-hospital setting.

This single-site feasibility study aims to understand whether it is practical to use POCT for the analysis of patients’ blood samples in the urgent and emergency care pre-hospital setting, through descriptive data of POCT application and through qualitative focus group interviews of advanced practitioners (specialist paramedics) to inform the feasibility and design of a larger study.

The primary outcome measure is focus group data measuring the experiences and perceived self-reported impact by specialist paramedics. Secondary outcome measures are number and type of cartridges used, number of successful and unsuccessful attempts in using the POCT analyser, length of time on scene, specialist paramedic recruitment and retention, number of patients who receive POCT, descriptive data of safe conveyance, patient demographics and presentations where POCT is applied and data quality.

The study results will inform the design of a main trial if indicated.

Aims, objectives and the research question

The aim of this study is to evaluate whether it is feasible for specialist paramedics to safely use a POCT blood analyser for the purpose of venous blood analysis in the urgent and emergency care setting to inform the design of a larger study. The primary objective is to understand their experiences of using the POCT analyser, and the self-reported impact it has on their clinical decision making when managing patients in the community. Secondary objectives will be to establish the practicality of using venous blood POCT in the emergency and urgent care setting, and to understand which patient populations it is most often applied to. Primary and secondary objectives, together with outcome measures, are detailed in Table 1.

Trial design

POCTPara is a 6-month single-site feasibility study designed to test the hypothesis that it is feasible for paramedics to utilise venous blood POCT analysers in the pre-hospital urgent and emergency care setting. This mixed-method study will utilise descriptive data from the specialist paramedic-participants’ case forms and usual ambulance data collection systems, in addition to a qualitative focus group. This feasibility trial is community-based, involving one team of 14 specialist paramedics based at a single ambulance station in the north of England.

Recruitment and consent

All 14 specialist paramedics will be invited to participate in the trial, with the aim to recruit 50% of the team subject to the inclusion and exclusion criteria in Table 2. The exclusion of patients with critical illness and requiring urgent intervention is so as not to extend the on-scene time. In addition, exclusion of non-English-speaking patients is related to this being a small-scale feasibility study, with funding restrictions for translation services; these patients would be included in any subsequent full research trial. A specialist paramedic participant information sheet (PIS) will provide further information and contact details for any discussion required.

Patient-participants will be identified by the specialist paramedic-participants during each patient care episode, according to trial procedures and the inclusion and exclusion criteria in Table 2. Any patient requiring life-saving intervention or time-critical transfer to hospital will be ineligible for study inclusion, and for all patients usual clinical assessment will not be affected. For patients meeting the eligibility criteria, the specialist paramedic-participants will deliver a scripted verbal explanation of the study and provide a patient-participant PIS along with the opportunity for further discussion prior to obtaining written consent. Due to the nature of the patient care episode, it is recognised that patient-participants will be unwell, which has the potential to affect their decision making; therefore, they will be provided with the opportunity to withdraw from the study in the following 7 days.

Withdrawal criteria

Both patients and participating specialist paramedics will be able to withdraw from the study at any point up to anonymising the data, and this will be made clear during the consent phase. For any specialist paramedic-participant who withdraws from the trial, any data already collected for the trial will continue to be used as they will have been anonymised, and this will be explained to the participant during the training phase, but no further data will be collected from the point of withdrawal.

Patient-participants can leave the study at any time without providing an explanation, up to 7 days from the patient care episode. After this time, the data will be anonymised and any personal identifiable data will be irretrievable as a result.

Training

All specialist paramedic-participants will be required to complete the National Institute for Health and Care Research (NIHR) Good Clinical Practice training before being invited to a mandatory 7-hour face-to-face session delivered by both clinical members of the trial team and representatives from the manufacturers of the POCT analyser. Training will include eligibility assessment, consent and recruitment procedures, test performance, result interpretation, data collection and adverse event (AE) or serious adverse event (SAE) reporting. Supporting documentation will be provided, including a quick reference guide to POCT result interpretation.

Trial intervention

Following informed written consent of a patient-participant, the specialist paramedic-participant will obtain a venous blood sample using either a butterfly needle or cannula and a 1 ml heparinised syringe. The analyser will be operated according to the manufacturer instructions. Where blood test results fall within the normal range, the specialist paramedic-participant will proceed with standard care. For any test results which fall outside the normal range or where there is clinical uncertainty, the trial procedures and quick reference material will provide written information regarding suggested management actions. Furthermore, where appropriate, a clinical discussion will be held with the patient’s own GP, out-of-hours GP or other relevant healthcare professional for decision support and agreement of a management plan.

Point-of-care testing blood results and analysis

All blood sample analysis will be performed utilising the i-STAT^® Alinity™ (Abbott Point of Care Inc, Princeton, NJ), a handheld point-of-care analyser intended for the quantitative measurement of various analytes in arterial, venous and capillary whole blood samples on single-use test cartridges. Calibration of the analyser is performed by an internal simulator test applied to every inserted cartridge, which simulates potentiometric, amperometric and conductometric signals at three different levels across a range that includes very high and very low concentrations of analytes corresponding to the cartridge type. Quality control evaluation is performed every six months, and will be undertaken prior to project commencement, in accordance with the manufacturer’s requirements.

For this feasibility study, cartridge use will be restricted to the CG4+ and CHEM8+ cartridges, which offer access to a range of analytes (Table 3). An a priori decision was taken to restrict access to a specific number of analytes (lactate, sodium, potassium, urea, creatinine, haemoglobin) deemed to have greatest utility due to the limited time available for training and education. Both cartridges require a minimum blood sample of 95 µL and provide analysis of results within 120 seconds.

Sample size calculation

A specific team of 14 specialist paramedics from one city in the north of England are being selected as they perform a different function to regular paramedics by targeting 999 calls that may be appropriate for management in the community; they also respond to care home and ambulance crew referrals. The specialist paramedic-participants work alone in a response car, may have access to SystmOne or Summary Care Records and typically do not have prior experience of POCT. A sample size of 50% of the team has been selected, to make communication easier for recruitment and trial management purposes.

Given that there are no published data on the patient populations that POCT could be applied to, and that this is a feasibility study to determine the practicality and utility of venous blood POCT analysers by specialist paramedics, a sample of 50 patients over 6 months has been selected. If the sample size of 50 patients is met before the 6-month period, the study will close early. No provision for over-recruitment has been made.

Data collection

All face-to-face patient care episodes that are attended by the specialist paramedic-participants will be considered for eligibility for POCT. The specialist paramedic-participant will complete their standard clinical assessment and seek consent for recruitment of those patients who meet the inclusion criteria.

The specialist paramedic-participant will then complete the ambulance service’s standard electronic patient record and the study case report form (CRF), from which data will be collected for the primary and secondary outcome measures. Routine data will also be collected by the ambulance control room systems.

Following closure of the study intervention, qualitative data will be collected through a 1.5-hour focus group with the specialist paramedic-participants to understand their experiences and self-reported impact of using POCT devices in the community. The focus group interview will be recorded, and notes taken; however, due to limited funding, transcription may not be possible in this feasibility study. The consolidated criteria for reporting qualitative research (COREQ) checklist will be used to consider quality and the methodology and reporting of the findings (Tong et al., 2007).

Data analysis

Descriptive data will be reported for the feasibility secondary outcome measures: number and type of cartridges used; number of successful and unsuccessful attempts in using the POCT analyser; length of time on scene; specialist paramedic recruitment and retention; number of patients who have POCT; descriptive data of safe conveyance; patient demographics and presentations where POCT is applied; and data quality. Missing data will be described but not used for data analysis and reporting. Interview data will be thematically analysed and manually coded by members of the research team, allowing for inductive identification of themes; a review of the resultant themes will be undertaken by the research group in order to form a consensus of the final themes.

Data management

Source data for the study will comprise the study data form which the recruited specialist paramedic-participants will complete for each consented patient episode. Computer-aided dispatch (CAD) records providing incident data, the patient’s care record (either paper or electronic) and the CRF (electronic) will have been completed by the participating specialist paramedic at the time of the incident. The data will be anonymised after data collection.

All data will be entered onto electronic spreadsheets, which will be securely held electronically on Trust servers, and all paper copies destroyed. No identifiable data will leave the Trust at any time, and identifiable data will be anonymised after seven days from the patient contact episode.

Direct access will be granted to authorised representatives from the sponsor, host institution and regulatory authorities to permit trial-related monitoring, audits and inspections in line with participant consent.

Archiving will be authorised by the sponsor following submission of the end-of-trial report. All source documentation will be archived on Trust electronic secure servers, with access limited to the immediate research team. All essential documents will be archived for a maximum of 10 years after completion of the trial. Destruction of essential documents will require sponsor authorisation. The study may be audited in line with routine audit processes laid out in the sponsor’s research governance policy. All source and essential documents will be available to the sponsor for audit for 10 years.

Peer review

Peer review has been provided to inform the content of the protocol, and was proportionate, independent and expert.

Public involvement

Yorkshire Ambulance Service NHS Trust (YAS) is fortunate to have patient research ambassadors who contributed to the design of the study, plain English summaries and the proposed dissemination plan. The study proposal was also presented to and discussed with the Sheffield Emergency Care Forum for the study setting comprising patient representatives and clinicians.

Protocol compliance

Any breach of protocol will be reported via the YAS Datix system to notify the co-chief investigators and the research and development (R&D) department at YAS. Duty of candour will be considered in consultation with the YAS duty-of-candour specialist.

Data protection and participant confidentiality

All investigators and trial site staff will comply with the requirements of the General Data Protection Regulations 2018, with regards to the collection, storage, processing and disclosure of personal information. Each participant will be allocated a unique study and location ID, and all identifiable data will be removed from the dataset to ensure anonymity. Access to the source documents will be restricted to the co-chief investigator and YAS R&D staff only. The co-chief investigators and statistician will be the only personnel to have access to the final full dataset, for the purposes of this study analysis.

Adverse events

The full study protocol defines AE reporting. Due to the nature of the emergency call trial setting, AE and SAE reporting by the paramedic-participant will only apply to events observed during the patient care episode. Proxy-safety data will also be collected during the 7-day period following the call related to any patient-participant-reported events and 72-hour recontact to the ambulance service. The study will be stopped by the co-chief investigators if reporting of AEs indicates that review of the study protocol is required, for any of the study intervention components.

Dissemination

The study results will be published in a peer-reviewed journal and will be disseminated through appropriate presentations, conferences and posters. A summary report will be presented to the funder, sponsor organisation, specialist paramedic-participants who wish to receive a copy and YAS. Social media, including Twitter and Facebook, will be utilised to highlight the publication of the study.

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