Prehospital critical care for out-of-hospital cardiac arrest: a complex intervention in a complex environment

BackgroundPrehospital critical care has the potential to improve the currently low survival rates following out-of-hospital cardiac arrest (OHCA). In some areas of the United Kingdom, prehospital critical care teams are dispatched to OHCA, while in others the standard of care of Advanced Life Support (ALS) is seen as sufficient. This thesis examines prehospital critical care for OHCA from different perspectives and aims to provide stakeholders in prehospital care with the information required to guide the funding and configuration of prehospital critical care for OHCA.Methods1. Qualitative analysis of stakeholders’ views on research and funding of prehospital critical care. Data from focus groups and interviews of five stakeholder groups were analysed using the framework approach.2. Economic analysis of ALS and prehospital critical care for OHCA. A decision analysis model of costs and effects of ALS for OHCA was created, using secondary data as well as data provided from relevant prehospital organisations. A range of possible effects of prehospital critical care for OHCA were simulated. A probabilistic sensitivity analysis was chosen to reflect the uncertainty of the underlying data.3. Prospective multicentre observational analysis, comparing survival to hospital discharge in patients with OHCA who received prehospital critical care or ALS. Propensity score matching was used to adjust for confounding and bias, subgroup analysis in patients with witnessed OHCA with shockable rhythm and two sensitivity analyses (primary dispatch and multiple imputation datasets) were used.4. Descriptive analysis of prehospital critical care interventions during and after OHCA. Frequencies of critical care interventions were analysed according to patient groups; a propensity score matching analysis examined the effect of treatment at a cardiac arrest centre in patients transferred to hospital.ResultsStakeholders expressed strong and often opposing views on a variety of topics discussed in regards to prehospital research, prehospital critical care and funding strategies.The current standard of care, Advanced Life Support (ALS) delivered by paramedics, was cost-effective at less than £20,000 per quality-adjusted life year (QALY) gained.After propensity score matching to account for an imbalance in prognostic factors, survival to hospital discharge did not differ between patients with OHCA receiving prehospital critical care or ALS care. These results were stable throughout the subgroup and sensitivity analyses. In addition, prehospital critical care for OHCA is considerable more expensive than ALS and therefore highly unlikely to be cost-effective.The reasons for this lack of clinical effectiveness of prehospital critical care can be likely found in the low frequency of interventions delivered and the relatively late arrival of critical care teams at the scene of an OHCA.Stakeholders’ considerations in regards to further funding of the complex intervention of prehospital critical care for OHCA will likely include additional factors such as social acceptability, available resources and the potential for indirect benefits.ConclusionsThis research provided a multi-faceted analysis of the complex intervention prehospital critical care for OHCA. The results can aid decision making in regards to future funding but also consider uncertainty in data analysis and the complex environment in which prehospital critical care is being delivered

Who does what in prehospital critical care? An analysis of competencies of paramedics, critical care paramedics and prehospital physicians

© 2014, BMJ Publishing Group. All rights reserved. Introduction: Emergency medical services in the UK are facing the challenge of responding to an increasing number of calls, often for non-emergency care, while also providing critical care to the few severely ill or injured patients. In response, paramedic training in the UK has been extended and there are regional strategies to improve prehospital critical care (PHCC). We describe the clinical competencies of three groups of prehospital providers in the UK with the aim of informing future planning of the delivery of PHCC. Methods: We used a data triangulation approach to obtain lists of competencies for paramedics, critical care paramedics (CCPs) and PHCC physicians of the Great Western Ambulance Service. Data sources were professional guidance documents, equipment available to the provider, log sheets of prehospital care episodes, direct observations and a survey of providers. Results: We identified 389, 441 and 449 competencies for paramedics, CCPs and PHCC physicians, respectively. Competencies of CCPs and PHCC physicians which exceeded those of paramedics can be arranged in four distinct clusters: induction and maintenance of anaesthesia, procedural sedation, advanced cardiovascular management and complex invasive interventions. Discussion: Paramedics possess a considerable number of competencies which allow them to diagnose and treat a variety of conditions. CCPs and PHCC physicians possess a few additional critical care competencies which are potentially life-saving but are required infrequently and can carry significant risks. Concentration of training and clinical exposure for a small group of providers in critical care teams can help optimising benefits and reducing risks of PHCC

Critical care paramedics in England: A national survey of ambulance services

Critical care paramedics (CCPs) have been introduced by individual ambulance trusts in England, but there is a lack of national coordination of training and practice. We conducted an online survey of NHS ambulance services to provide an overview of the current utilization and role of CCPs in England. The survey found significant variations in training, competencies and the working patterns of the ∼90 CCPs working in five ambulance services. All ambulance trusts currently employing CCPs are planning on increasing CCP numbers, whereas 'insufficient financial means' and 'insufficient scientific evidence' are the two major barriers to CCP utilization. The CCP model established in five ambulance services in England is unique within Europe. With increasing numbers of CCPs, concerns about lack of supportive scientific evidence and clinical need should be addressed. Optimal delivery of prehospital critical care in England remains controversial. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins

The impact of a pre-hospital critical care team on survival from out-of-hospital cardiac arrest

© 2015 Elsevier Ireland Ltd. Aim: To assess the impact of a pre-hospital critical care team (CCT) on survival from out-of-hospital cardiac arrest (OHCA). Methods: We undertook a retrospective observational study, comparing OHCA patients attended by advanced life support (ALS) paramedics with OHCA patients attended by ALS paramedics and a CCT between April 2011 and April 2013 in a single ambulance service in Southwest England. We used multiple logistic regression to control for an anticipated imbalance of prognostic factors between the groups. The primary outcome was survival to hospital discharge. All data were collected independently of the research. Results: 1851 cases of OHCA were included in the analysis, of which 1686 received ALS paramedic treatment and 165 were attended by both ALS paramedics and a CCT. Unadjusted rates of survival to hospital discharge were significantly higher in the CCT group, compared to the ALS paramedic group (15.8% and 6.5%, respectively,

Critical care paramedics: Where is the evidence? A systematic review

© 2014, BMJ Publishing Group. All rights reserved. Objectives: Paramedic-delivered prehospital critical care is an established concept in a number of emergency medical services around the world and, more recently, has been introduced to the UK. This review identifies and describes the available evidence relating to paramedics who routinely provide prehospital critical care as primary scene response (critical care paramedics, or CCP). Methods: A systematic search of electronic databases was performed: CENTRAL, EMBASE, MEDLINE (through EMBASE and Web of Knowledge) and Web of Science (through Web of Knowledge). Results: The search identified 12 relevant publications, one of which was a randomised controlled trial. The remaining 11 were retrospective studies. Five studies compared CCPs with physician-led care. Three of these publications demonstrated improved outcomes with physician care, while two showed no difference. Four further publications examined CCPs versus non-physician-led care and found improved outcomes (two studies), mixed effects (one study) and no difference (one study) for CCPs. Finally, three publications addressed the addition of skills to CCP competencies. A randomised controlled trial of CCP rapid sequence induction (RSI) and tracheal intubation demonstrated improved neurologic outcomes. CCP tube thoracostomy was shown to have similar complication rates to the same procedure performed in the emergency department, while addition of a non-invasive ventilation protocol to CCP practice had no effect on long-term mortality. Conclusions: There is limited evidence to support the concept of paramedic-delivered prehospital critical care. The best available evidence suggests a benefit from prehospital RSI carried out by CCPs in patients with severe traumatic brain injury, but the impact of CCPs remains unclear for many conditions. Further high-quality research in this area would be welcome

Systematic review of the effectiveness of prehospital critical care following out-of-hospital cardiac arrest

© 2017 Background Improving survival after out-of-hospital cardiac arrest (OHCA) is a priority for modern emergency medical services (EMS) and prehospital research. Advanced life support (ALS) is now the standard of care in most EMS. In some EMS, prehospital critical care providers are also dispatched to attend OHCA. This systematic review presents the evidence for prehospital critical care for OHCA, when compared to standard ALS care. Methods We searched the following electronic databases: PubMed, EmBASE, CINAHL Plus and AMED (via EBSCO), Cochrane Database of Systematic Reviews, DARE, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, NIHR Health Technology Assessment Database, Google Scholar and ClinicalTrials.gov. Search terms related to cardiac arrest and prehospital critical care. All studies that compared patient-centred outcomes between prehospital critical care and ALS for OHCA were included. Results The review identified six full text publications that matched the inclusion criteria, all of which are observational studies. Three studies showed no benefit from prehospital critical care but were underpowered with sample sizes of 1028–1851. The other three publications showed benefit from prehospital critical care delivered by physicians. However, an imbalance of prognostic factors and hospital treatment in these studies systematically favoured the prehospital critical care group. Conclusion Current evidence to support prehospital critical care for OHCA is limited by the logistic difficulties of undertaking high quality research in this area. Further research needs an appropriate sample size with adjustments for confounding factors in observational research design

Cost-effectiveness of advanced life support and prehospital critical care for out-of-hospital cardiac arrest in England: a decision analysis model

Objectives: This research aimed to answer the following questions: What are the costs of prehospital advanced life support (ALS) and prehospital critical care for outof-hospital cardiac arrest (OHCA)? What is the cost effectiveness of prehospital ALS? What improvement in survival rates from OHCA would prehospital critical care need to achieve in order to be cost-effective? Setting A single National Health Service ambulance service and a charity-funded prehospital critical care service in England.Participants : The patient population is adult, nontraumatic OHCA.Methods: We combined data from previously published research with data provided by a regional ambulance service and air ambulance charity to create a decision tree model, coupled with a Markov model, of costs and outcomes following OHCA. We compared no treatment for OHCA to the current standard of care of prehospitalALS, and prehospital ALS to prehospital critical care. To reflect the uncertainty in the underlying data, we used probabilistic and two-way sensitivity analyses.Results: Costs of prehospital ALS and prehospital critical care were £347 and £1711 per patient, respectively. When costs and outcomes of prehospital, in-hospital and postdischarge phase of OHCA care were combined, prehospital ALS was estimated to be cost-effective at £11407/quality-adjusted life year. In order to be cost-effective in addition to ALS, prehospital critical care for OHCA would need to achieve a minimally economically important difference (MEID) in survival to hospital discharge of 3%–5%.Conclusion: This is the first economic analysis to address the question of cost-effectiveness of prehospital critical care following OHCA. While costs of either prehospital ALS and/or critical care per patient with OHCA are relatively low, significant costs are incurred during hospital treatment and after discharge in patients who survive.Knowledge of the MEID for prehospital critical care can guide future research in this field.Trial registration number ISRCTN1837520

Prehospital anaesthesia by a physician and paramedic critical care team in Southwest England

OBJECTIVES: Prehospital anaesthesia using rapid sequence induction (RSI) is carried out internationally and in the UK despite equivocal evidence of clinical benefit. It is a core skill of the prehospital critical care service established by the Great Western Ambulance Service NHS Trust (GWAS) in 2008. This retrospective analysis of the service's first 150 prehospital RSIs describes intubation success rates and complications, thereby contributing towards the ongoing debate on its role and safety. METHODS: Within the GWAS critical care team, RSI is only carried out in the presence of a qualified physician and critical care paramedic (CCP). The role of the intubating practitioner is interchangeable between physician and CCP. Data were collected retrospectively from RSI audit forms and electronic patient monitor printouts. RESULTS: GWAS physician and CCP teams undertook 150 prehospital RSIs between June 2008 and August 2011. The intubation success rate was 82, 91 and 97% for the first, second and third attempts, respectively. Successful intubation on the first attempt was achieved in 58 (85%) and 64 (78%) patients for physicians and CCPs, respectively. RSI complications included hypoxaemia (10.2%), hypotension (9.7%) and bradycardia (1.3%). CONCLUSION: Prehospital RSI can be carried out safely, with intubation success rates and complications comparable with RSI in the emergency department. The variation in the intubation success rates between individual practitioners highlights the importance of ongoing performance monitoring, coupled with high standards of clinical governance and training. © 2013 Wolters Kluwer Health Lippincott Williams & Wilkins

Response to: Influence of EMS-physician presence on survival after out-of-hospital cardiopulmonary resuscitation

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The effect of prehospital critical care on survival following out-of-hospital cardiac arrest: A prospective observational study

AimTo examine the effect of prehospital critical care on survival following OHCA, compared to routine advanced life support (ALS) care.MethodsWe undertook a prospective multi-centre cohort study including two ambulance services and six prehospital critical care services in the United Kingdom (UK), between September 2016 and October 2017. Inclusion criteria were adult patients with non-traumatic OHCA treated by either prehospital critical care teams or ALS paramedics. Patients who received prehospital critical care were matched to those receiving ALS using propensity score matching. Primary outcome was survival to hospital discharge; secondary outcome was survival to hospital admission.ResultsThe primary analysis included 658 patients with OHCA receiving prehospital critical care and 1,847 patients receiving ALS care. Rates of survival to hospital discharge (primary outcome) were 11.9% in both groups; rates of survival to hospital admission (secondary outcome) were 34.4% and 27.7% in the prehospital critical care and ALS group, respectively. The corresponding odds ratios for survival to hospital discharge and survival to hospital admission with prehospital critical care were 1.06 (95% confidence interval 0.75 – 1.49) and 1.39 (95% confidence interval 1.10 – 1.75), respectively. Results were consistent across subgroups and sensitivity analyses.ConclusionsDespite a positive association with the secondary outcome of survival to hospital admission, prehospital critical care was not associated with increased rates of survival to hospital discharge following OHCA