How consistent are pre-alert guidelines? A review of UK ambulance service guidelines

Aims

Ambulance pre-alerts are used to inform receiving emergency departments (EDs) of the arrival of critically unwell or rapidly deteriorating patients who need time-critical assessment or treatment immediately upon arrival. Inappropriate use of pre-alerts can lead to EDs diverting resources from other critically ill patients. However, there is limited guidance about how pre-alerts should be undertaken, delivered or communicated. We aimed to map existing pre-alert guidance from UK NHS ambulance services to explore consistency and accessibility of existing guidance.

Methods

We contacted all UK ambulance services to request documentation containing guidance about pre-alerts. We reviewed and mapped all guidance to understand which conditions were recommended for a pre-alert and alignment with Association of Ambulance Chief Executives (AACE) and Royal College of Emergency Medicine (RCEM) pre-alert guidance. We reviewed the language and accessibility of guidance using the AGREE II tool.

Results

We received responses from 15/19 UK ambulance services and 10 stated that they had specific pre-alert guidance. We identified noticeable variations in conditions declared suitable for pre-alerts in each service, with a lack of consistency within each ambulance service's own guidance, and a lack of alignment with the AACE/RCEM pre-alert guidance. Services listed between four and 45 different conditions suitable for pre-alert. There were differences in physiological thresholds and terminology, even for conditions with established care pathways (e.g. hyperacute stroke, ST segment elevation myocardial infarction). Pre-alert criteria were typically listed in several short sections in lengthy handover procedure policy documents. Documents appraised were of poor quality with low scores below 35% for applicability and overall.

Implications

There is a clear need for ambulance services to have both policies and tools that complement each other and incorporate the same list of pre-alertable conditions. Clinicians need a single, easily accessible document to refer to in a time-critical situation to reduce the risk of making an incorrect pre-alert decision.

Prehospital early warning scores for adults with suspected sepsis: the PHEWS observational cohort and decision-analytic modelling study

Background

Guidelines for sepsis recommend treating those at highest risk within 1 hour. The emergency care system can only achieve this if sepsis is recognised and prioritised. Ambulance services can use prehospital early warning scores alongside paramedic diagnostic impression to prioritise patients for treatment or early assessment in the emergency department.

Objectives

To determine the accuracy, impact and cost-effectiveness of using early warning scores alongside paramedic diagnostic impression to identify sepsis requiring urgent treatment.

Design

Retrospective diagnostic cohort study and decision-analytic modelling of operational consequences and cost-effectiveness.

Setting

Two ambulance services and four acute hospitals in England.

Participants

Adults transported to hospital by emergency ambulance, excluding episodes with injury, mental health problems, cardiac arrest, direct transfer to specialist services, or no vital signs recorded.

Interventions

Twenty-one early warning scores used alongside paramedic diagnostic impression, categorised as sepsis, infection, non-specific presentation, or other specific presentation.

Main outcome measures

Proportion of cases prioritised at the four hospitals; diagnostic accuracy for the sepsis-3 definition of sepsis and receiving urgent treatment (primary reference standard); daily number of cases with and without sepsis prioritised at a large and a small hospital; the minimum treatment effect associated with prioritisation at which each strategy would be cost-effective, compared to no prioritisation, assuming willingness to pay £20,000 per quality-adjusted life-year gained.

Results

Data from 95,022 episodes involving 71,204 patients across four hospitals showed that most early warning scores operating at their pre-specified thresholds would prioritise more than 10% of cases when applied to non-specific attendances or all attendances. Data from 12,870 episodes at one hospital identified 348 (2.7%) with the primary reference standard. The National Early Warning Score, version 2 (NEWS2), had the highest area under the receiver operating characteristic curve when applied only to patients with a paramedic diagnostic impression of sepsis or infection (0.756, 95% confidence interval 0.729 to 0.783) or sepsis alone (0.655, 95% confidence interval 0.63 to 0.68). None of the strategies provided high sensitivity (> 0.8) with acceptable positive predictive value (> 0.15). NEWS2 provided combinations of sensitivity and specificity that were similar or superior to all other early warning scores. Applying NEWS2 to paramedic diagnostic impression of sepsis or infection with thresholds of > 4, > 6 and > 8 respectively provided sensitivities and positive predictive values (95% confidence interval) of 0.522 (0.469 to 0.574) and 0.216 (0.189 to 0.245), 0.447 (0.395 to 0.499) and 0.274 (0.239 to 0.313), and 0.314 (0.268 to 0.365) and 0.333 (confidence interval 0.284 to 0.386). The mortality relative risk reduction from prioritisation at which each strategy would be cost-effective exceeded 0.975 for all strategies analysed.

Limitations

We estimated accuracy using a sample of older patients at one hospital. Reliable evidence was not available to estimate the effectiveness of prioritisation in the decision-analytic modelling.

Conclusions

No strategy is ideal but using NEWS2, in patients with a paramedic diagnostic impression of infection or sepsis could identify one-third to half of sepsis cases without prioritising unmanageable numbers. No other score provided clearly superior accuracy to NEWS2. Research is needed to develop better definition, diagnosis and treatments for sepsis.

Study registration

This study is registered as Research Registry (reference: researchregistry5268).

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 17/136/10) and is published in full in Health Technology Assessment; Vol. 28, No. 16. See the NIHR Funding and Awards website for further award information.

Prehospital early warning scores for adults with suspected sepsis: retrospective diagnostic cohort study

BACKGROUND

Ambulance services need to identify and prioritise patients with sepsis for early hospital assessment. We aimed to determine the accuracy of early warning scores alongside paramedic diagnostic impression to identify sepsis that required urgent treatment.

METHODS

We undertook a retrospective diagnostic cohort study involving adult emergency medical cases transported to Sheffield Teaching Hospitals ED by Yorkshire Ambulance Service in 2019. We used routine ambulance service data to calculate 21 early warning scores and categorise paramedic diagnostic impressions as sepsis, infection, non-specific presentation or other presentation. We linked cases to hospital records and identified those meeting the sepsis-3 definition who received urgent hospital treatment for sepsis (reference standard). Analysis determined the accuracy of strategies that combined early warning scores at varying thresholds for positivity with paramedic diagnostic impression.

RESULTS

We linked 12 870/24 955 (51.6%) cases and identified 348/12 870 (2.7%) with a positive reference standard. None of the strategies provided sensitivity greater than 0.80 with positive predictive value greater than 0.15. The area under the receiver operating characteristic curve for the National Early Warning Score, version 2 (NEWS2) applied to patients with a diagnostic impression of sepsis or infection was 0.756 (95% CI 0.729, 0.783). No other early warning score provided clearly superior accuracy to NEWS2. Paramedic impression of sepsis or infection had sensitivity of 0.572 (0.519, 0.623) and positive predictive value of 0.156 (0.137, 0.176). NEWS2 thresholds of >4, >6 and >8 applied to patients with a diagnostic impression of sepsis or infection, respectively, provided sensitivities and positive predictive values of 0.522 (0.469, 0.574) and 0.216 (0.189, 0.245), 0.447 (0.395, 0.499) and 0.274 (0.239, 0.313), and 0.314 (0.268, 0.365) and 0.333 (0.284, 0.386).

CONCLUSION

No strategy is ideal but using NEWS2 alongside paramedic diagnostic impression of infection or sepsis could identify one-third to half of sepsis cases without prioritising unmanageable numbers. No other score provided clearly superior accuracy to NEWS2.

TRIAL REGISTRATION NUMBER

researchregistry5268, https://www.researchregistry.com/browse-the-registry%23home/registrationdetails/5de7bbd97ca5b50015041c33/.

PP26 Exploring the use of pre-hospital pre-alerts and their impact on patients, ambulance service and emergency department staff: protocol for a mixed methods study

Background

Ambulance clinicians use pre-alert calls to inform receiving emergency departments (EDs) of the arrival of a critically unwell patient that will require a specialised response. Little is known about how a decision to pre-alert is made and how this is communicated and acted upon in the receiving ED. Whilst appropriate use of pre-alerts benefits patient care, their overuse carries a risk of harm or opportunity costs. The impact of pre-alerts on ambulance clinicians, ED staff and patients is not currently well understood.

Methods

We are conducting a mixed methods study with five inter-related work packages. We will analyse 12 months of routine data from ambulance pre-alerts in three regions to identify factors in the variation of pre-alert use, including pre-hospital decision-making. We will undertake a national online Qualtrics survey of ambulance clinician perspectives and experience of pre-alerts. We will explore the impacts of a pre-alert on staff, ED facilities and the patient using semi-structured interviews with ambulance clinicians, ED staff, patients and carers and undertake non-participant observation of ED pre-alert response.

Expected Results

We will describe current pre-alert practice using 12 months’ data for 3 Ambulance Services, including volume and types of pre-alerts. We will identify specific conditions or patient groups for whom pre-alerts are most likely to lead to change in clinical practice, or for whom action is unlikely to provide benefit. We will hold a feedback workshop in which we will share and discuss our findings with key stakeholders.

Conclusions

Current variation in pre-alert processes, both pre-hospital and in-hospital and the impact on patient care is not understood. The outputs of this study will establish an evidence base to update national guidance for pre-alert practice and identify areas of good pre-alert practice for both ambulance service and Emergency Department staff.

Soiled airway tracheal intubation and the effectiveness of decontamination by paramedics: a randomised controlled manikin study protocol

Vomiting and regurgitation are commonly encountered in out-of-hospital cardiac arrest with a reported incidence of 20–30%. Arguably, tracheal intubation is the preferred airway management technique in patients with ongoing airway contamination, but there is evidence that this is difficult to achieve when the airway is soiled. In addition, traditional suctioning techniques have been criticised, and training in the management of contaminated airways is limited. If standard suctioning techniques are not sufficient to maintain a clear airway and provide ventilation, then these patients will die, irrespective of the quality of chest compressions and the timeliness of defibrillation. This has led to the development of a combined suction/laryngoscopy technique to facilitate intubation, known as Suction Assisted Laryngoscopy and Airway Decontamination, and the creation of modified airway manikins to allow for practice in these techniques. However, to date there has only been one study specifically looking at the Suction Assisted Laryngoscopy and Airway Decontamination technique, and the outcomes were self-reported confidence measures of trainees in using the technique.

The primary objective of Soiled Airway Tracheal Intubation and the Effectiveness of Decontamination is to determine the difference between paramedic first-pass intubation success, before and after Suction Assisted Laryngoscopy and Airway Decontamination training, in a simulated soiled airway. The primary outcome is the difference in proportions of paramedic first-pass intubation success, before and after Suction Assisted Laryngoscopy and Airway Decontamination training.

Paramedic recruitment commenced in July 2018 and the study will enrol 154 paramedics by the end of 2018. The results of this study will contribute to the evidence relating to the Suction Assisted Laryngoscopy and Airway Decontamination technique.

Consensus statement: a framework for safe and effective intubation by paramedics

This consensus statement provides profession-specific guidance in relation to tracheal intubation by paramedics – a procedure that the College of Paramedics supports.

Tracheal intubation by paramedics has been the subject of professional and legal debate as well as crown investigation. It is therefore timely that the College of Paramedics, through this consensus group, reviews the available evidence and expert opinion in order to prevent patient harm and promote patient safety, clinical effectiveness and professional standards.

It is not the purpose of this consensus statement to remove the skill of tracheal intubation from paramedics. Neither is it intended to debate the efficacy of intubation or the effect on mortality or morbidity, as other formal research studies will answer those questions.

The consensus of this group is that paramedics can perform tracheal intubation safely and effectively. However, a safe, well-governed system of continual training, education and competency must be in place to serve both patients and the paramedics delivering their care.