Could paramedics use the HEART Pathway to identify patients at low-risk of myocardial infarction in the prehospital setting?

In the Emergency Department, patients with suspected myocardial infarction can be risk stratified using the HEART pathway, which has recently been amended for prehospital use and modified for the incorporation of a high-sensitivity cardiac troponin test. In a prospective analysis, the performance of both HEART pathways in the prehospital setting, with a high-sensitivity cardiac troponin test using 3 different thresholds, was evaluated for major adverse cardiac events at 30 days. We found that both low-risk HEART pathways, when using the most conservative cardiac troponin thresholds, approached but did not reach accepted rule-out performance in the Emergency Department.

Patient and staff perceptions of short procedural sedation with propofol for joint and fracture reductions in the Emergency Department: A qualitative study.

BACKGROUND: Emergency Department (ED) propofol sedation is widely used to facilitate reduction of fractures and dislocations, but little is known about patient and staff perceptions of the practice. Better understanding of these aspects may improve patient care. METHODS: A qualitative exploratory study involving semi-structured patient interviews and ED healthcare professional focus groups. Interviews with adult patients (≥16 years) >1 hour after their sedation episode were audio-recorded, anonymised and transcribed verbatim to an electronic database. Thematic analysis using a general inductive method led to development of codes and themes. ED focus groups recordings were similarly transcribed and triangulated to patient interview outcomes. RESULTS: Data saturation was reached after 16 patient interviews. Emergent central themes from a patient perspective were: 'fear of the unknown' and 'expressed relief that the procedure was comfortable.' Key themes included 'trust in the clinical team,' 'efficacy of pain management prior to sedation' and 'quality of the information delivered to patients.' Focus group discussions around patient interview outcomes identified triage, analgesia delivery, communication, and consideration of the environment as areas for improvement. CONCLUSIONS: ED procedural sedation with propofol is generally very well accepted by patients and clinical staff but there is scope to improve patient-focus and increase satisfaction.

Performance of a prehospital HEART score in patients with possible myocardial infarction: a prospective evaluation.

INTRODUCTION: The History, Electrocardiogram (ECG), Age, Risk Factors and Troponin (HEART) score is commonly used to risk stratify patients with possible myocardial infarction as low risk or high risk in the Emergency Department (ED). Whether the HEART score can be used by paramedics to guide care were high-sensitivity cardiac troponin testing available in a prehospital setting is uncertain. METHODS: In a prespecified secondary analysis of a prospective cohort study where paramedics enrolled patients with suspected myocardial infarction, a paramedic Heart, ECG, Age, Risk Factors (HEAR) score was recorded contemporaneously, and a prehospital blood sample was obtained for subsequent cardiac troponin testing. HEART and modified HEART scores were derived using laboratory contemporary and high-sensitivity cardiac troponin I assays. HEART and modified HEART scores of ≤3 and ≥7 were applied to define low-risk and high-risk patients, and performance was evaluated for an outcome of major adverse cardiac events (MACEs) at 30 days. RESULTS: Between November 2014 and April 2018, 1054 patients were recruited, of whom 960 (mean 64 (SD 15) years, 42% women) were eligible for analysis and 255 (26%) experienced a MACE at 30 days. A HEART score of ≤3 identified 279 (29%) as low risk with a negative predictive value of 93.5% (95% CI 90.0% to 95.9%) for the contemporary assay and 91.4% (95% CI 87.5% to 94.2%) for the high-sensitivity assay. A modified HEART score of ≤3 using the limit of detection of the high-sensitivity assay identified 194 (20%) patients as low risk with a negative predictive value of 95.9% (95% CI 92.1% to 97.9%). A HEART score of ≥7 using either assay gave a lower positive predictive value than using the upper reference limit of either cardiac troponin assay alone. CONCLUSIONS: A HEART score derived by paramedics in the prehospital setting, even when modified to harness the precision of a high-sensitivity assay, does not allow safe rule-out of myocardial infarction or enhanced rule-in compared with cardiac troponin testing alone.

Diagnostic Accuracy of Clinical Pathways for Suspected Acute Myocardial Infarction in the Out-of-Hospital Environment.

STUDY OBJECTIVE: Chest pain is one of the most common reasons for emergency ambulance calls. Patients are routinely transported to the hospital to prevent acute myocardial infarction (AMI). We evaluated the diagnostic accuracy of clinical pathways in the out-of-hospital environment. The Troponin-only Manchester Acute Coronary Syndromes decision aid and History, ECG, Age, Risk Factors, Troponin score require cardiac troponin (cTn) measurement, whereas the History and ECG-only Manchester Acute Coronary Syndromes decision aid and History, ECG, Age, Risk Factors score do not. METHODS: We conducted a prospective diagnostic accuracy study at 4 ambulance services and 12 emergency departments between February 2019 and March 2020. We included patients who received an emergency ambulance response in whom paramedics suspected AMI. Paramedics recorded the data required to calculate each decision aid and took venous blood samples in the out-of-hospital environment. Samples were tested using a point-of-care cTn assay (Roche cobas h232) within 4 hours. The target condition was a diagnosis of type 1 AMI, adjudicated by 2 investigators. RESULTS: Of 817 included participants, 104 (12.8%) had AMI. Setting the cutoff at the lowest risk group, Troponin-only Manchester Acute Coronary Syndromes had 98.3% sensitivity (95% confidence interval 91.1% to 100%) and 25.5% specificity (21.4% to 29.8%) for type 1 AMI. History, ECG, Age, Risk Factors, Troponin had 86.4% sensitivity (75.0% to 98.4%) and 42.2% specificity (37.5% to 47.0%); History and ECG-only Manchester Acute Coronary Syndromes had 100% sensitivity (96.4% to 100%) and 3.1% specificity (1.9% to 4.7%), whereas History, ECG, Age, Risk Factors had 95.1% sensitivity (88.9% to 98.4%) and 12.1% specificity (9.8% to 14.8%). CONCLUSION: With point-of-care cTn testing, decision aids can identify patients at a low risk of type 1 AMI in the out-of-hospital environment. When used alongside clinical judgment, and with appropriate training, such tools may usefully enhance out-of-hospital risk stratification.

External validation of the Manchester Acute Coronary Syndromes ECG risk model within a pre-hospital setting.

OBJECTIVES: The Manchester Acute Coronary Syndromes ECG (MACS-ECG) prediction model calculates a score based on objective ECG measurements to give the probability of a non-ST elevation myocardial infarction (NSTEMI). The model showed good performance in the emergency department (ED), but its accuracy in the pre-hospital setting is unknown. We aimed to externally validate MACS-ECG in the pre-hospital environment. METHODS: We undertook a secondary analysis from the Pre-hospital Evaluation of Sensitive Troponin (PRESTO) study, a multi-centre prospective study to validate decision aids in the pre-hospital setting (26 February 2019 to 23 March 2020). Patients with chest pain where the treating paramedic suspected acute coronary syndrome were included. Paramedics collected demographic and historical data and interpreted ECGs contemporaneously (as 'normal' or 'abnormal'). After completing recruitment, we analysed ECGs to calculate the MACS-ECG score, using both a pre-defined threshold and a novel threshold that optimises sensitivity to differentiate AMI from non-AMI. This was compared with subjective ECG interpretation by paramedics. The diagnosis of AMI was adjudicated by two investigators based on serial troponin testing in hospital. RESULTS: Of 691 participants, 87 had type 1 AMI and 687 had complete data for paramedic ECG interpretation. The MACS-ECG model had a C-index of 0.68 (95% CI: 0.61 to 0.75). At the pre-determined cut-off, MACS-ECG had 2.3% (95% CI: 0.3% to 8.1%) sensitivity, 99.5% (95% CI: 98.6% to 99.9%) specificity, 40.0% (95% CI: 10.2% to 79.3%) positive predictive value (PPV) and 87.6% (87.3% to 88.0%) negative predictive value (NPV). At the optimal threshold for sensitivity, MACS-ECG had 50.6% sensitivity (39.6% to 61.5%), 83.1% specificity (79.9% to 86.0%), 30.1% PPV (24.7% to 36.2%) and 92.1% NPV (90.4% to 93.5%). In comparison, paramedics had a sensitivity of 71.3% (95% CI: 60.8% to 80.5%) with 53.8% (95% CI: 53.8% to 61.8%) specificity, 19.7% (17.2% to 22.45%) PPV and 93.3% (90.8% to 95.1%) NPV. CONCLUSION: Neither MACS-ECG nor paramedic ECG interpretation had a sufficiently high PPV or NPV to 'rule in' or 'rule out' NSTEMI alone.

The impact of minimum unit pricing on traumatic brain injury in Scotland: a retrospective cohort study of routine national data.

BACKGROUND: Traumatic brain injury (TBI) is a common cause of disability and mortality and is associated with alcohol consumption. On 1st May 2018, the Scottish Government introduced Minimum Unit Pricing (MUP) legislation which set the floor price at which alcohol can be sold to 50 pence per unit. While MUP has led to a 7.6% decrease in off trade alcohol purchases, there are limited studies investigating the clinical impact of this legislation. This study aims to explore the impact of MUP on traumatic brain injury in Scotland. METHODS: Retrospective cohort study using routinely collected national data collated by the Scottish Trauma Audit Group. Data were requested for all TBI incidents from 1st May to 31st December for both 2017 and 2018. Primary outcome was alcohol-related TBI. Secondary outcomes were injury mechanism, injury severity, clinical course, and short-term mortality. Analysis was conducted using multiple regression models adjusted for age, sex, season, and deprivation. RESULTS: A total of 1166 patients (66% male, and 46% in the 60-79-year bracket) were identified. Alcohol-related TBI was evident in 184 of 509 (36%) patients before MUP and in 239 of 657 (36%) patients injured after its implementation (p = 0.638). Further, there was no change in injury mechanism, injury severity, hospital course and short-term mortality of TBI after MUP. CONCLUSIONS: MUP has not resulted in a change in alcohol-related TBI nor in the mechanism and severity of TBI. Limitations in two-point analysis mean that findings should be interpreted with caution and further studies investigating the clinical outcomes of MUP must be conducted.

Venous thromboembolism risk following temporary immobilisation after injury: evaluation of the Aberdeen VTE risk tool.

BACKGROUND: Temporary lower limb immobilisation following injury is a risk factor for symptomatic venous thromboembolism (VTE). Pharmacological thromboprophylaxis can mitigate this risk but it is unclear which patients benefit from this intervention. The Aberdeen VTE risk tool was developed to tailor thromboprophylaxis decisions in these patients and this evaluation aimed to describe its performance in clinical practice. Secondarily, diagnostic metrics were compared with other risk assessment methods (RAMs). METHODS: A prospective cohort service evaluation was conducted. Adult patients (≥16 years) managed with lower limb immobilisation for injury who were evaluated with the Aberdeen VTE risk tool prior to discharge from the ED were identified contemporaneously between February 2014 and December 2020. Electronic patient records were scrutinised up to 3 months after removal of immobilisation for the development of symptomatic VTE or sudden death due to pulmonary embolism (PE). Other RAMs, including the Thrombosis Risk Prediction for Patients with cast immobilisation (TRiP(cast)) and Plymouth scores, were assimilated retrospectively and diagnostic performance compared. RESULTS: Of 1763 patients (mean age 46 (SD 18) years, 51% women), 15 (0.85%, 95% CI 0.52% to 1.40%) suffered a symptomatic VTE or death due to PE. The Aberdeen VTE tool identified 1053 (59.7%) patients for thromboprophylaxis with a sensitivity of 80.0% (95% CI 54.8% to 93.0%) and specificity of 40.4% (95% CI 38.1% to 42.6%) for the primary outcome. In 1695 patients, fewer were identified as high risk by the TRiP(cast) (33.3%) and Plymouth (24.4%) scores, but with greater specificity, 67.0% and 75.6%, respectively, than dichotomous RAMs, including the Aberdeen VTE tool. CONCLUSION: Routine use of the Aberdeen VTE tool in our population resulted in an incidence of symptomatic VTE of less than 1%. Ordinal RAMs, such as the TRiP(cast) score, may more accurately reflect VTE risk and permit more individually tailored thromboprophylaxis decisions but prospective comparison is needed.

Accuracy of substance exposure history in patients attending emergency departments after substance misuse; a comparison with biological sample analysis.

CONTEXT: Acute toxicity caused by illicit substance use is a common reason for emergency department (ED) presentation. Knowledge of the substances involved is helpful for predicting and managing potential toxicity, but limited information is available about the accuracy of patient-reported substance exposure. This study assessed the accuracy of the history of exposure in those reporting use of a single substance by comparison with those identified by detailed toxicological analysis, focusing on synthetic cannabinoid receptor agonists (SCRA). METHODS: Adults (≥16 years) presenting between March 2015 and July 2021 to participating UK hospitals with toxicity after reporting use of a single illicit substance were included. Exposure details were documented from medical records and blood and/or urine samples analysed using high-resolution accurate mass liquid chromatography-mass spectrometry (HRAM LCMS). Sensitivity, specificity, and positive and negative predictive values of the exposure history were calculated by comparison with biological sample analysis ("gold standard"). RESULTS: Single substance exposure was reported for 474 (median age 33 years, IQR: 18 range 16-75, 80% males) patients. Analysis commonly identified multiple substances (Median 3, IQR 2-5). A history of exposure was documented for 121 of 151 patients where a SCRA or metabolite was detected on analysis (sensitivity 80.1%, 95% CI 72.9, 86.2%). Corresponding proportions were lower for 3,4-methylenedioxymethamphetamine (MDMA, 44/70, 62.9%., 95% CI 50.5%, 74.1%), heroin 41/108 (38.0% 95% CI 28.8-47.8%) and cocaine (22/56, 31.3%, 95% CI 20.9, 43.6%). CONCLUSIONS: Multiple undeclared substances were detected analytically in most patients reporting single substance use. Clinicians should be alert to the potential presence and toxicity of unreported substances when managing patients presenting after substance misuse.

The suboptimal fibrinolytic response in COVID-19 is dictated by high PAI-1.

BACKGROUND: Severe COVID-19 disease is associated with thrombotic complications and extensive fibrin deposition. This study investigates whether the hemostatic complications in COVID-19 disease arise due to dysregulation of the fibrinolytic system. METHODS: This prospective study analyzed fibrinolytic profiles of 113 patients hospitalized with COVID-19 disease with 24 patients with non-COVID-19 respiratory infection and healthy controls. Antigens were quantified by Ella system or ELISA, clot lysis by turbidimetric assay, and plasminogen activator inhibitor-1 (PAI-1)/plasmin activity using chromogenic substrates. Clot structure was visualized by confocal microscopy. RESULTS: PAI-1 and its cofactor, vitronectin, are significantly elevated in patients with COVID-19 disease compared with those with non-COVID-19 respiratory infection and healthy control groups. Thrombin activatable fibrinolysis inhibitor and tissue plasminogen activator were elevated in patients with COVID-19 disease relative to healthy controls. PAI-1 and tissue plasminogen activator (tPA) were associated with more severe COVID-19 disease severity. Clots formed from COVID-19 plasma demonstrate an altered fibrin network, with attenuated fiber length and increased branching. Functional studies reveal that plasmin generation and clot lysis were markedly attenuated in COVID-19 disease, while PAI-1 activity was elevated. Clot lysis time significantly correlated with PAI-1 levels. Stratification of COVID-19 samples according to PAI-1 levels reveals significantly faster lysis when using the PAI-1 resistant (tPA) variant, tenecteplase, over alteplase lysis. CONCLUSION: This study shows that the suboptimal fibrinolytic response in COVID-19 disease is directly attributable to elevated levels of PAI-1, which attenuate plasmin generation. These data highlight the important prognostic potential of PAI-1 and the possibility of using pre-existing drugs, such as tenecteplase, to treat COVID-19 disease and potentially other respiratory diseases.

The Ambulance Cardiac Chest Pain Evaluation in Scotland Study (ACCESS): A Prospective Cohort Study.

STUDY OBJECTIVE: To determine whether risk stratification in the out-of-hospital setting could identify patients with chest pain who are at low and high risk to avoid admission or aid direct transfer to cardiac centers. METHODS: Paramedics prospectively enrolled patients with suspected acute coronary syndrome without diagnostic ST-segment elevation on the ECG. The History, ECG, Age and Risk Factors (HEAR) score was recorded contemporaneously, and out-of-hospital samples were obtained to measure cardiac Troponin I (cTnI) level on a point-of-care device, to allow calculation of the History, ECG, Age, Risk Factors, and Troponin (HEART) score. HEAR and HEART scores less than or equal to 3 and greater than or equal to 7 were defined as low and high risk for major adverse cardiac events at 30 days. RESULTS: Of 1,054 patients (64 years [SD 15 years]; 42% women), 284 (27%) experienced a major adverse cardiac event at 30 days. The HEAR score was calculated in all patients, with point-of-care cTnI testing available in 357 (34%). A HEAR score less than or equal to 3 identified 32% of patients (334/1,054) as low risk, with a sensitivity of 84.9% (95% confidence interval [CI] 80.7% to 89%), whereas a score greater than or equal to 7 identified just 3% of patients (30/1,054) as high risk, with a specificity of 98.7% (95% CI 97.9% to 99.5%). A point-of-care HEART score less than or equal to 3 identified a similar proportion as low risk (30%), with a sensitivity of 87.0% (95% CI 80.7% to 93.4%), whereas a score greater than or equal to 7 identified 14% as high risk, with a specificity of 94.8% (95% CI 92.0% to 97.5%). CONCLUSION: Paramedics can use the HEAR score to discriminate risk, but even when used in combination with out-of-hospital point-of-care cTnI testing, the HEART score does not safely rule out major adverse cardiac events, and only a small proportion of patients are identified as high risk.

Pneumorrhachis after Recreational Drug Use.

Pneumorrhachis, the presence of air in the spinal canal, is an unusual and alarming radiographic finding. The etiology is most commonly traumatic or iatrogenic but it can occur as a spontaneous phenomenon in association with pneumomediastinum. We report the case of a 16 year old male who presented with throat discomfort and a feeling of altered voice after recreational drug use. Examination confirmed widespread subcutaneous emphysema above the clavicles and plain radiograph and computed tomography imaging confirmed the presence of extensive pneumomediastinum and pneumorrhachis. The patient was managed conservatively and made a full recovery. The clinical and imaging features of spontaneous pneumorrhachis are presented as well as a review of the literature with regard to pathogenesis, management and outcome. Knowledge and understanding of this unusual phenomenon is important to properly direct patient care.

Risk stratifying chest pain patients in the emergency department using HEART, GRACE and TIMI scores, with a single contemporary troponin result, to predict major adverse cardiac events.

BACKGROUND: The majority of patients presenting to the ED with cardiac sounding chest pain have a non-diagnostic ECG and the problem of differentiating those suffering an acute coronary syndrome from those without is familiar to all ED clinical staff. To stratify risk in these patients, specific scores have been developed. Recent work has focused on incorporating newer high-sensitivity cardiac troponin (hs-cTn) assays; however, issues regarding performance and availability of these assays remain. AIM: Prospectively compare HEART, Global Registry of Acute Coronary Events (GRACE) and Thrombolysis in Myocardial Infarction (TIMI) scores, using a single contemporary cTn at admission, to predict a major adverse cardiac event (MACE) at 30 days. METHOD: Prospective observational cohort study performed in a UK tertiary hospital in patients with suspected cardiac chest pain and no significant ST elevation on initial ECG. Data collection took place 2 December 2014 to 8 February 2016. The treating clinician recorded risk score data real time and a single contemporary cTn taken at presentation was used in score calculation. The primary endpoint was 30-day MACE. C-statistic was determined for each score and diagnostic characteristics of high-risk and low-risk cut-offs were calculated. RESULTS: 189/1000 patients in the study developed a 30-day MACE. The c-statistic of HEART for 30-day MACE (0.87 (95% CI 0.84 to 0.90)) was higher than TIMI (0.78 (95% CI 0.74 to 0.81)) and GRACE (0.74 (95% CI 0.70 to 0.78)).HEART score ≤3 identified low-risk patients with sensitivity 99.5% (95% CI 97.1% to 99.9%) and negative predictive value (NPV) 99.6% (95% CI 97.3% to 99.9%) exceeding TIMI 0 (sensitivity 97.4% (95% CI 93.9% to 99.1%) and NPV 97.8% (95% CI 94.8% to 99.1%)) and GRACE score 0-55 (sensitivity 95.2% (95% CI 91.1% to 97.8%) and NPV 95.8% (95% CI 92.2% to 97.7%)). CONCLUSION: HEART outperformed both TIMI and GRACE in overall discriminative capacity for 30-day MACE. Using a single contemporary cTn at presentation, a HEART score of ≤3 demonstrated sensitivity and NPV of ≥99.5% for 30-day MACE. These results reach the threshold for a safe discharge strategy but should be interpreted thoughtfully in light of other work.

The Lazarus phenomenon: spontaneous cardioversion after termination of resuscitation in a Scottish hospital.

A 66-year-old man suffered a ventricular fibrillation cardiac arrest after an episode of chest pain. Despite advanced life support, his condition deteriorated; the situation was considered irrecoverable and resuscitation was discontinued. The patient was observed for about 5 min with irregular agonal gasping respirations evident but no palpable pulse. A gradual increase in the regularity of breathing pattern heralded the return of spontaneous circulation. An inferior myocardial infarction was diagnosed. Primary percutaneous coronary intervention was performed. The patient was discharged from hospital after 9 days with no neurological sequelae. There are several possible mechanisms to explain the Lazarus phenomenon including auto-positive end expiratory pressure and delayed drug actions, but cases are rarely reported in the medical literature. After discontinued resuscitation, we suggest consideration should be given to a period of continued monitoring. However, evidence is limited and prospective studies would be welcome to allow firmer recommendations.

The choking hazard of grapes: a plea for awareness.

Deaths from choking are a major cause of childhood mortality, especially in the very young. Whole grapes are ideally suited to cause paediatric airway obstruction and, though regularly implicated, knowledge that this popular fruit, and other similarly shaped foods, is a choking hazard is not widespread. We present the cases of three children who presented to our institution after grape aspiration. Increased dissemination of the learning points among health professionals working with children may aid in the prevention of further episodes.