RePHILL: protocol for a randomised controlled trial of pre-hospital blood product resuscitation for trauma.

OBJECTIVES: To describe the 'Resuscitation with Pre-HospItaL bLood products' trial (RePHILL) - a multi-centre randomised controlled trial of pre-hospital blood product (PHBP) administration vs standard care for traumatic haemorrhage. BACKGROUND: PHBP are increasingly used for pre-hospital trauma resuscitation despite a lack of robust evidence demonstrating superiority over crystalloids. Provision of PHBP carries additional logistical and regulatory implications, and requires a sustainable supply of universal blood components. METHODS: RePHILL is a multi-centre, two-arm, parallel group, open-label, phase III randomised controlled trial currently underway in the UK. Patients attended by a pre-hospital emergency medical team, with traumatic injury and hypotension (systolic blood pressure <90 mmHg or absent radial pulse) believed to be due to traumatic haemorrhage are eligible. Exclusion criteria include age <16 years, blood product receipt on scene prior to randomisation, Advanced Medical Directive forbidding blood product administration, pregnancy, isolated head injury and prisoners. A total of 490 patients will be recruited in a 1 : 1 ratio to receive either the intervention (up to two units of red blood cells and two units of lyophilised plasma) or the control (up to four boluses of 250 mL 0.9% saline). The primary outcome measure is a composite of failure to achieve lactate clearance of ≥20%/h over the first 2 hours after randomisation and all-cause mortality between recruitment and discharge from the primary receiving facility to non-acute care. Secondary outcomes include pre-hospital time, coagulation indices, in-hospital transfusion requirements and morbidity. RESULTS: Pilot study recruitment began in December 2016. Approval to proceed to the main trial was received in June 2017. Recruitment is expected to continue until 2020. CONCLUSIONS: RePHILL will provide high-quality evidence regarding the efficacy and safety of PHBP resuscitation for trauma.

Increasing survival after admission to UK critical care units following cardiopulmonary resuscitation.

BACKGROUND: In recent years there have been many developments in post-resuscitation care. We have investigated trends in patient characteristics and outcome following admission to UK critical care units following cardiopulmonary resuscitation (CPR) for the period 2004-2014. Our hypothesis is that there has been a reduction in risk-adjusted mortality during this period. METHODS: We undertook a prospectively defined, retrospective analysis of the Intensive Care National Audit & Research Centre (ICNARC) Case Mix Programme Database (CMPD) for the period 1 January 2004 to 31 December 2014. Admissions, mechanically ventilated in the first 24 hours in the critical care unit and admitted following CPR, defined as the delivery of chest compressions in the 24 hours before admission, were identified. Case mix, withdrawal, outcome and activity were described annually for all admissions identified as post-cardiac arrest admissions, and separately for out-of-hospital cardiac arrest and in-hospital cardiac arrest. To assess whether in-hospital mortality had improved over time, hierarchical multivariate logistic regression models were constructed, with in-hospital mortality as the dependent variable, year of admission as the main exposure variable and intensive care unit (ICU) as a random effect. All analyses were repeated using only the data from those ICUs contributing data throughout the study period. RESULTS: During the period 2004-2014 survivors of cardiac arrest accounted for an increasing proportion of mechanically ventilated admissions to ICUs in the ICNARC CMPD (9.0 % in 2004 increasing to 12.2 % in 2014). Risk-adjusted hospital mortality following admission to ICU after cardiac arrest has decreased significantly during this period (OR 0.96 per year). Over this time, the ICU length of stay and time to treatment withdrawal has increased significantly. Re-analysis including only those 116 ICUs contributing data throughout the study period confirmed all the results of the primary analysis. CONCLUSIONS: Risk-adjusted hospital mortality following admission to ICU after cardiac arrest has decreased significantly during the period 2004-2014. Over the same period the ICU length of stay and time to treatment withdrawal has increased significantly.

The accuracy of prehospital triage decisions in English trauma networks - a case-cohort study.

BACKGROUND: Care for injured patients in England is provided by inclusive regional trauma networks. Ambulance services use triage tools to identify patients with major trauma who would benefit from expedited Major Trauma Centre (MTC) care. However, there has been no investigation of triage performance, despite its role in ensuring effective and efficient MTC care. This study aimed to investigate the accuracy of prehospital major trauma triage in representative English trauma networks. METHODS: A diagnostic case-cohort study was performed between November 2019 and February 2020 in 4 English regional trauma networks as part of the Major Trauma Triage Study (MATTS). Consecutive patients with acute injury presenting to participating ambulance services were included, together with all reference standard positive cases, and matched to data from the English national major trauma database. The index test was prehospital provider triage decision making, with a positive result defined as patient transport with a pre-alert call to the MTC. The primary reference standard was a consensus definition of serious injury that would benefit from expedited major trauma centre care. Secondary analyses explored different reference standards and compared theoretical triage tool accuracy to real-life triage decisions. RESULTS: The complete-case case-cohort sample consisted of 2,757 patients, including 959 primary reference standard positive patients. The prevalence of major trauma meeting the primary reference standard definition was 3.1% (n=54/1,722, 95% CI 2.3 - 4.0). Observed prehospital provider triage decisions demonstrated overall sensitivity of 46.7% (n=446/959, 95% CI 43.5-49.9) and specificity of 94.5% (n=1,703/1,798, 95% CI 93.4-95.6) for the primary reference standard. There was a clear trend of decreasing sensitivity and increasing specificity from younger to older age groups. Prehospital provider triage decisions commonly differed from the theoretical triage tool result, with ambulance service clinician judgement resulting in higher specificity. CONCLUSIONS: Prehospital decision making for injured patients in English trauma networks demonstrated high specificity and low sensitivity, consistent with the targets for cost-effective triage defined in previous economic evaluations. Actual triage decisions differed from theoretical triage tool results, with a decreasing sensitivity and increasing specificity from younger to older ages.

Randomised controlled trial of analgesia for the management of acute severe pain from traumatic injury: study protocol for the paramedic analgesia comparing ketamine and morphine in trauma (PACKMaN).

BACKGROUND: Prehospital analgesia is often required after traumatic injury, currently morphine is the strongest parenteral analgesia routinely available for use by paramedics in the United Kingdom (UK) when treating patients with severe pain. This protocol describes a multi-centre, randomised, double blinded trial comparing the clinical and cost-effectiveness of ketamine and morphine for severe pain following acute traumatic injury. METHODS: A two arm pragmatic, phase III trial working with two large NHS ambulance services, with an internal pilot. Participants will be randomised in equal numbers to either (1) morphine or (2) ketamine by IV/IO injection. We aim to recruit 446 participants over the age of 16 years old, with a self-reported pain score of 7 or above out of 10. Randomised participants will receive a maximum of 20 mg of morphine, or a maximum of 30 mg of ketamine, to manage their pain. The primary outcome will be the sum of pain intensity difference. Secondary outcomes measure the effectiveness of pain relief and overall patient experience from randomisation to arrival at hospital as well as monitoring the adverse events, resource use and cost-effectiveness outcomes. DISCUSSION: The PACKMAN study is the first UK clinical trial addressing the clinical and cost-effectiveness of ketamine and morphine in treating acute severe pain from traumatic injury treated by NHS paramedics. The findings will inform future clinical practice and provide insights into the effectiveness of ketamine as a prehospital analgesia. TRIAL REGISTRATION: ISRCTN, ISRCTN14124474. Registered 22 October 2020, https://www.isrctn.com/ISRCTN14124474.

The nationwide impact of COVID-19 on life support courses. A retrospective evaluation by Resuscitation Council UK.

Aim: To determine the impact of the COVID-19 pandemic on Resuscitation Council UK Advanced Life Support (ALS) and Immediate Life Support (ILS) course numbers and outcomes. Methods: We conducted a before-after study using course data from the Resuscitation Council UK Learning Management System between January 2018 and December 2021, using 23 March 2020 as the cut-off between pre- and post-pandemic periods. Demographics and outcomes were analysed using chi-squared tests and regression models. Results: There were 90,265 ALS participants (51,464 pre-; 38,801 post-) and 368,140 ILS participants (225,628 pre-; 142,512 post-). There was a sharp decline in participants on ALS/ILS courses due to COVID-19. ALS participant numbers rebounded to exceed pre-pandemic levels, whereas ILS numbers recovered to a lesser degree with increased uptake of e-learning versions. Mean ALS course participants reduced from 20.0 to 14.8 post-pandemic (P < 0.001).Post-pandemic there were small but statistically significant decreases in ALS Cardiac Arrest Simulation Test pass rates (from 82.1 % to 80.1 % (OR = 0.90, 95 % CI = 0.86-0.94, P < 0.001)), ALS MCQ score (from 86.6 % to 86.0 % (mean difference = -0.35, 95 % CI -0.44 to -0.26, P < 0.001)), and overall ALS course results (from 95.2 %to 94.7 %, OR = 0.92, CI = 0.85-0.99, P = 0.023). ILS course outcomes were similar post-pandemic (from 99.4 % to 99.4 %, P = 0.037). Conclusion: COVID-19 caused a sharp decline in the number of participants on ALS/ILS courses and an accelerated uptake of e-learning versions, with the average ALS course size reducing significantly. The small reduction in performance on ALS courses requires further research to clarify the contributing factors.

Resuscitation highlights in 2021.

BACKGROUND: This review is the latest in a series of regular annual reviews undertaken by the editors and aims to highlight some of the key papers published in Resuscitation during 2021. METHODS: Hand-searching by the editors of all papers published in Resuscitation during 2021. Papers were selected based on then general interest and novelty and were categorised into themes. RESULTS: 98 papers were selected for brief mention. CONCLUSIONS: Resuscitation science continues to evolve and incorporates all links in the chain of survival.

Bystander cardiopulmonary resuscitation for paediatric out-of-hospital cardiac arrest in England: An observational registry cohort study.

INTRODUCTION: Bystander cardiopulmonary resuscitation (BCPR) is strongly advocated by resuscitation councils for paediatric out-of-hospital cardiac arrests (OHCAs). However, there are limited reports on rates of BCPR in children and its relationship with return of spontaneous circulation (ROSC) or survival outcomes. OBJECTIVE: We describe the rate of BCPR and its association with any ROSC and survival- to- hospital-discharge. METHODS: We conducted retrospective analysis of prospectively collected paediatric (<18 years of age) OHCA cases in England; we included specialist registry patients treated by emergency medical services (EMS) with known BCPR status and outcome between January 2014 and November 2018. Data included patient demographics, aetiology, witness status, initial rhythm, EMS, season, time of day and bystander status. Associations between BCPR, and any ROSC and survival-to-hospital-discharge outcomes were explored using multivariable logistic regression. RESULTS: There were 2363 paediatric OHCAs treated across 11 EMS regions. BCPR was performed in 69.6% (1646/2363) of the cases overall (range 57.7% (206/367) to 83.7% (139/166) across EMS regions). Only 34.9% (550/1572) of BCPR cases were witnessed. Overall, any ROSC was achieved in 22.8% (523/2289) and survival to hospital discharge in 10.8% (225/2066). Adjusted odds ratio (aOR) for any ROSC was significantly improved following BCPR compared to no BCPR (aOR 1.37, 95% CI 1.03-1.81), but adjusted odds ratio for survival-to-hospital-discharge were similar (aOR 1.01, 95% CI 0.66-1.55). CONCLUSIONS: BCPR was associated with improved rates of any ROSC but not survival-to-hospital-discharge. Variations in EMS BCPR rates may indicate opportunities for regional targeted increase in public BCPR education.

Sugar or salt ("SOS"): A protocol for a UK multicentre randomised trial of mannitol and hypertonic saline in severe traumatic brain injury and intracranial hypertension.

Hyperosmolar solutions are widely used to treat raised intracranial pressure following severe traumatic brain injury. Although mannitol has historically been the most frequently administered, hypertonic saline solutions are increasingly being used. However, definitive evidence regarding their comparative effectiveness is lacking. The Sugar or Salt Trial is a UK randomised, allocation concealed open label multicentre pragmatic trial designed to determine the clinical and cost-effectiveness of hypertonic saline compared with mannitol in the management of patients with severe traumatic brain injury. Patients requiring intensive care unit admission and intracranial pressure monitoring post-traumatic brain injury will be allocated at random to receive equi-osmolar boluses of either mannitol or hypertonic saline following failure of routine first-line measures to control intracranial pressure. The primary outcome for the study will be the Extended Glasgow Outcome Scale assessed at six months after randomisation. Results will inform current clinical practice in the routine use of hyperosmolar therapy as well as assess the impact of potential side effects. Pre-planned longer term clinical and cost effectiveness analyses will further inform the use of these treatments.

Neutrophil chemotaxis in granulomatosis with polyangiitis (Wegener's) and idiopathic pulmonary fibrosis.

The presence of antineutrophil cytoplasmic antibodies in granulomatosis with polyangiitis (Wegener's) (GPA) implicates the neutrophil as a key effector cell. Previous studies have reported elevated neutrophil counts in the lung, although the determinants of neutrophil chemotaxis in the GPA lung are unknown. Bronchoalveolar lavage fluid (BALF) cell counts, myeloperoxidase (MPO) and chemokines were measured in 27 patients with GPA, 20 disease controls with idiopathic pulmonary fibrosis (IPF) and six healthy controls. CXC chemokine ligand (CXCL)8, interleukin (IL)-1ß, epithelial neutrophil-activating protein 78, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor were measured by ELISA. The neutrophil chemotactic potential of BALF was investigated using the under-agarose method, and specific antibodies were used to examine the role of CXCL8 and IL-1ß. GPA BALF had an increased neutrophil percentage, and elevated MPO, CXCL8 and G-CSF concentrations compared with healthy controls. Chemotaxis of control neutrophils towards BALF from patients with active (p=0.006) and remission (p=0.077) GPA, and IPF (p=0.001) patients was increased compared with normal controls. BALF-induced chemotaxis correlated with BALF IL-1ß (r=0.761, p=0.001) and CXCL8 (r=0.640, p=0.012) in GPA, and was inhibited by anti-CXCL8 (85%; p<0.001) and anti-IL-1ß (69%; p<0.001). Our study confirms a neutrophilia and pro-inflammatory alveolar milieu that persists in clinical remission. CXCL8 and IL-1ß appear to play important roles in the neutrophil chemotactic response to BALF.

Does the prophylactic administration of magnesium sulphate to patients undergoing thoracotomy prevent postoperative supraventricular arrhythmias? A randomized controlled trial.

BACKGROUND: Supraventricular arrhythmias (SVA) are common after thoracic surgery and are associated with increased morbidity and mortality. This prospective, randomized, double-blind, placebo-controlled trial examined the effects of perioperative magnesium on the development of postoperative SVA. METHODS: Two hundred patients undergoing thoracotomy for lobectomy, bi-lobectomy, pneumonectomy, or oesophagectomy were recruited and randomly allocated into two groups. The treatment group received magnesium (5 g daily) intraoperatively, and on days 1 and 2 after operation, the control group received placebo. The primary outcome of the study was the development of SVA within the first 5 days after operation. RESULTS: There were 100 patients in each arm of the study, with one withdrawal and three lost to follow-up in the treatment group and four withdrawals in the control group. Ninety-six patients received magnesium and 96 received placebo. There was no difference in the incidence of SVA between the treatment and control groups, 16.7% (16/96) vs 25% (24/96), P=0.16. In the predefined subgroup analysis, patients at highest risk of arrhythmias (those undergoing pneumonectomy) had a significant reduction in the frequency of SVA, 11.1% (2/18) vs 52.9% (9/17), P=0.008. There were no differences in hospital length of stay or mortality. Patients receiving i.v. magnesium experienced a higher frequency of minor side-effects (stinging at injection site). The treatment was otherwise well tolerated. CONCLUSIONS: Overall, prophylactic magnesium did not reduce the incidence of SVA in patients undergoing thoracotomy. However, it reduced the incidence of SVA in the high-risk cohort of patients undergoing pneumonectomy. (ISRCTN22028180.).

A national clinical scenario-based survey of clinicians' attitudes towards fresh frozen plasma transfusion for critically ill patients.

BACKGROUND: It is known that 20-30% of fresh frozen plasma (FFP) is used in intensive care units (ICUs), but little is known about variations in decision making between clinicians in relation to coagulopathy management. Our aim was to describe ICU clinicians' beliefs and practice in relation to FFP treatment of non-bleeding coagulopathic critically ill patients. METHODS: Two patient-based scenarios were developed and sent to 2700 members of two UK intensive care professional societies. Scenario 1 was a non-bleeding septic patient with coagulopathy; scenario 2 was a non-bleeding critically ill patient with hepatic cirrhosis and coagulopathy. Responses were sought in relation to FFP prophylaxis, and prior to central venous cannulation. A supplementary question asked clinicians' view of prophylaxis in relation to other ICU procedures. RESULTS: Two-thousand-and-seven-hundred clinicians were surveyed from whom 601 responses were received (22·3% response rate). For scenario 1 52% of respondents stated that they would never routinely administer prophylactic FFP, but this decreased to 9% when central venous cannulation was planned (P < 0·01). There was wide variation in the 'trigger' INR (international normalised ratio) value used prior to central vein cannulation, the most common range being 2·0-2·4. For scenario 2, responses were very similar. More than 80% of clinicians stated that they would routinely treat coagulopathy prior to lumbar puncture, epidural catheterisation, intracranial pressure monitoring and tracheostomy; and 54% prior to chest drain insertion. CONCLUSION: Our survey demonstrated a wide range of responses consistent with important variations in clinical practice and substantial clinical uncertainty in relation to FFP treatment for non-bleeding ICU patients.

A randomised control trial to determine if use of the iResus© application on a smart phone improves the performance of an advanced life support provider in a simulated medical emergency.

This study sought to determine whether using the Resuscitation Council UK's iResus© application on a smart phone improves the performance of doctors trained in advanced life support in a simulated emergency. Thirty-one doctors (advanced life support-trained within the previous 48 months) were recruited. All received identical training using the smart phone and the iResus application. The participants were randomly assigned to a control group (no smart phone) and a test group (access to iResus on smart phone). Both groups were tested using a validated extended cardiac arrest simulation test (CASTest) scoring system. The primary outcome measure was the overall cardiac arrest simulation test score; these were significantly higher in the smart phone group (median (IQR [range]) 84.5 (75.5-92.5 [64-96])) compared with the control group (72 (62-87 [52-95]); p=0.02). Use of the iResus application significantly improves the performance of an advanced life support-certified doctor during a simulated medical emergency. Further studies are needed to determine if iResus can improve care in the clinical setting.

Resuscitation highlights in 2020.

BACKGROUND: This review is the latest in a series of regular annual reviews undertaken by the editors and aims to highlight some of the key papers published in Resuscitation during 2020. The number of papers submitted to the Journal in 2020 increased by 25% on the previous year.MethodsHand-searching by the editors of all papers published in Resuscitation during 2020. Papers were selected based on then general interest and novelty and were categorised into general themes.ResultsA total of 103 papers were selected for brief mention in this review.ConclusionsResuscitation science continues to evolve rapidly and incorporate all links in the chain of survival.

Characteristics of Restart a Heart 2019 event locations in the UK.

INTRODUCTION: Restart a Heart (RSAH) is an annual CPR mass training initiative delivered predominantly by ambulance services in the UK. The aim of this study was to identify to what extent voluntary participation in the 2019 initiative delivered training to the population with the highest need. METHODS: A cross-sectional observational study of location characteristics for RSAH training events conducted by UK ambulance services. Descriptive statistics were used to analyse event and area characteristics. National cardiac arrest registry data were used to establish proportions of training coverage in "hot spot" areas with above national median incidence of cardiac arrest and below median bystander CPR rates. The significance of observed differences were tested using chi-square for proportions and t-test for means. RESULTS: Twelve of 14 UK ambulance services participated, training 236,318 people. Most of the events (82%) were held in schools, and schoolchildren comprised most participants (81%). RSAH events were held in areas that were less densely populated (p < 0.001), were more common in affluent areas (p < 0.001), and had a significantly lower proportion of black residents (p < 0.05) and higher proportion of white residents (p < 0.05). Events were held in 28% of known "hot spot" areas in England. CONCLUSION: With mandatory CPR training for school children in England, Scotland and Wales there is an opportunity to re-focus RSAH resources to deliver training for all age groups in OHCA "hot spots", communities with higher proportions of black residents, and areas of deprivation. In Northern Ireland, we recommend targeting schools in areas with similar characteristics.

Outcomes and interventions in patients transported to hospital with ongoing CPR after out-of-hospital cardiac arrest - An observational study.

INTRODUCTION: The main objective was to present characteristics and outcome of patients without sustained field return of spontaneous circulation (ROSC) transported to hospital with ongoing cardiopulmonary resuscitation (CPR). Our secondary objectives were to investigate hospital-based interventions and the performance of the universal Termination of Resuscitation-rule (uTOR). METHODS: In this retrospective observational cohort study, out-of-hospital cardiac arrest (OHCA) patients arriving to the emergency department of a university hospital in Sweden during a six-year period (2010-2015) were identified using a prospectively recorded hospital-based registry. Additional data were retrieved from medical records and from the Swedish cardiopulmonary resuscitation registry. RESULTS: Among 409 patients transported with ongoing CPR, 7 survived to hospital discharge (1.7%). Hospital-based interventions against a suspected cause of arrest were attempted during ongoing resuscitation in 34 patients (8.3%), of whom 3 survived to hospital discharge. The remaining 4 survivors had spontaneous in-hospital ROSC. Survivors presented with either a shockable rhythm (n = 4) or pulseless electrical activity (n = 3). The uTOR identified non-survivors with a positive predictive value (PPV) of 98.4% and a specificity of 71.4% for termination. CONCLUSION: Survival after OHCA where sustained prehospital ROSC is not achieved is rare and available in-hospital interventions are rarely utilised. No patient with asystole as the first recorded rhythm survived. The uTOR identified non-survivors with a PPV of 98.4% but showed poor specificity.

Changes in temperature management and outcome after out-of-hospital cardiac arrest in United Kingdom intensive care units following publication of the targeted temperature management trial.

AIM: To investigate how the publication of the targeted temperature management (TTM) trial in December 2013 affected the trends in temperature management and outcome following admission to UK intensive care units (ICUs) after out-of-hospital cardiac arrest (OHCA). METHODS: We used a national ICU database of 1,181,405 consecutive admissions to 235 adult ICUs. OHCA admissions mechanically ventilated in the first 24 h in the ICU were divided into a pre-TTM trial cohort of patients admitted before publication of the TTM trial (January 2010-December 2013) and post-TTM cohort of patients admitted after TTM trial publication (January 2014-December 2017). The primary outcome variables were lowest temperature in the first 24 h in ICU and survival to hospital discharge. RESULTS: The lowest temperature recorded in the first-24 h of admission was significantly higher in the post-TTM cohort (n = 18,106) than in the pre-TTM cohort (n = 12,162) (mean 34.7 (±1.6) versus 33.6 °C (±1.8); absolute difference 1.12 °C (95% CI 1.08-1.16). The post-TTM cohort had a greater prevalence of fever (>38.0 °C) (24.8% vs 14.7%; (odds ratio (OR) 1.91 (95% CI 1.80-2.03); p < 0.001)) and higher unadjusted in-hospital mortality (63.7% vs 61.6%). In a multilevel model, accounting for time trend and including site as a random effect, neither the step change in acute hospital mortality following publication of the TTM trial result (OR 1.04, 95% CI 0.95-1.15; p = 0.37), nor the change in slope (from OR 1.00 per year, 95% CI 0.97-1.04, to 1.04 per year, 95% CI 1.02-1.07; p = 0.059), was statistically significant. Adjusted analyses were limited by the models' dependence on temperature and temperature-related variables. CONCLUSIONS: The lowest temperature recorded in the first-24 h of admission in OHCA patients was higher in the post-TTM cohort compared with the pre-TTM cohort. There has been an increase in the proportion of patients with fever (>38 °C) in the first 24 h. Although crude mortality was slightly higher in the post-TTM cohort, an analysis accounting for time trend and variation between critical care units, found no significant change associated with the TTM publication.

Resuscitation and emergency care in drowning: A scoping review.

BACKGROUND: The ILCOR Basic Life Support Task Force and the international drowning research community considered it timely to undertake a scoping review of the literature to identify evidence relating to the initial resuscitation, hospital-based interventions and criteria for safe discharge related to drowning. METHODS: Medline, PreMedline, Embase, Cochrane Reviews and Cochrane CENTRAL were searched from 2000 to June 2020 to identify relevant literature. Titles and abstracts and if necessary full text were reviewed in duplicate. Studies were eligible for inclusion if they reported on the population (adults and children who are submerged in water), interventions (resuscitation in water/boats, airway management, oxygen administration, AED use, bystander CPR, ventilation strategies, ECMO, protocols for hospital discharge (I), comparator (standard care) and outcomes (O) survival, survival with a favourable neurological outcome, CPR quality, physiological end-points). RESULTS: The database search yielded 3242 references (Medline 1104, Pre-Medline 202, Embase 1722, Cochrane reviews 12, Cochrane CENTRAL 202). After removal of duplicates 2377 papers were left for screening titles and abstracts. In total 65 unique papers were included. The evidence identified was from predominantly high-income countries and lacked consistency in the populations, interventions and outcomes reported. Clinical studies were exclusively observational in nature. CONCLUSION: This scoping review found that there is very limited evidence from observational studies to inform evidence based clinical practice guidelines for drowning. The review highlights an urgent need for high quality research in drowning.