Prehospital point-of-care ultrasound in ruptured abdominal aortic aneurysms-a retrospective cohort study

BACKGROUND

Patients with ruptured abdominal aortic aneurysm (rAAA) require immediate vascular treatment to survive. The use of prehospital point-of-care ultrasound (POCUS) may support clinical assessment, correct diagnosis, appropriate triage and reduce system delay. The aim was to study the process of care and outcome in patients receiving prehospital POCUS versus patients not receiving prehospital POCUS in patients with rAAA, ruptured iliac aneurysm or impending aortic rupture.

METHODS

We performed a retrospective cohort study in patients diagnosed with rAAA in the Central Denmark Region treated by a prehospital critical care physician from 1 January 2017 to 31 December 2021. Performance of prehospital POCUS was extracted from the prehospital electronic health records. System delay was defined as the time from the emergency phone call to the emergency medical service dispatch centre until the start of surgery. Data on patients primary hospital admission to a centre with/without vascular treatment expertise, treatments and complications including death were extracted from electronic health records.

RESULTS

We included 169 patients; prehospital POCUS was performed in 124 patients (73%). Emergency surgical treatment was performed in 71 patients. The overall survival in the POCUS group was 39% versus 16% in the NO POCUS group (hazard ratio (HR) (95% 0.60, 95% CI: 0.41-0.89, p = .011). In the POCUS group 99/124 (80%) were directly admitted to a vascular surgical centre versus 25/45 (56%) in the NO POCUS, RD 24% (95% CI: 8-40)), (p = .002). In the POCUS group, system delay was a median of 142 minutes (interquartile range (IQR) 121-189) and a median of 232 minutes (IQR 166-305) in the NO POCUS group (p = .006). In a multivariable analysis incorporating age, sex, previously known rAAA, and typical clinical symptoms of rAAA, the HR for death was 0.57, 95% CI 0.38-0.86 (p = .008) favouring prehospital POCUS.

CONCLUSIONS

Prehospital POCUS was associated with reduced time to treatment, higher chance of operability and significantly higher 30-day survival in patients with rAAA, ruptured iliac aneurysm or impending rupture of an AAA in this retrospective study. Residual confounding cannot be excluded. This study supports the clinical relevance of prehospital POCUS of the abdominal aorta.

Association Between Defibrillation Using LIFEPAK 15 or ZOLL X Series and Survival Outcomes in Out-of-Hospital Cardiac Arrest: A Nationwide Cohort Study

BACKGROUND

Defibrillation is essential for achieving return of spontaneous circulation (ROSC) following out-of-hospital cardiac arrest (OHCA) with shockable rhythms. This study aimed to investigate if the type of defibrillator used was associated with ROSC in OHCA.

METHODS AND RESULTS

This study included adult patients with OHCA from the Danish Cardiac Arrest Registry from 2016 to 2021 with at least 1 defibrillation by the emergency medical services. We used multivariable logistic regression and a difference-in-difference analysis, including all patients with or without emergency medical services shock to assess the causal inference of using the different defibrillator models (LIFEPAK or ZOLL) for OHCA defibrillation. Among 6516 patients, 77% were male, the median age (quartile 1; quartile 3) was 70 (59; 79), and 57% achieved ROSC. In total, 5514 patients (85%) were defibrillated using LIFEPAK (ROSC: 56%) and 1002 patients (15%) were defibrillated using ZOLL (ROSC: 63%). Patients defibrillated using ZOLL had an increased adjusted odds ratio (aOR) for ROSC compared with LIFEPAK (aOR, 1.22 [95% CI, 1.04-1.43]). There was no significant difference in 30-day mortality (aOR, 1.11 [95% CI, 0.95-1.30]). Patients without emergency medical services defibrillation, but treated by ZOLL-equipped emergency medical services, had a nonsignificant aOR for ROSC compared with LIFEPAK (aOR, 1.10 [95% CI, 0.99-1.23]) and the difference-in-difference analysis was not statistically significant (OR, 1.10 [95% CI, 0.91-1.34]).

CONCLUSIONS

Defibrillation using ZOLL X Series was associated with increased odds for ROSC compared with defibrillation using LIFEPAK 15 for patients with OHCA. However, a difference-in-difference analysis suggested that other factors may be responsible for the observed association.

Accelerated -Rule-Out of acute Myocardial Infarction using prehospital copeptin and in-hospital troponin: The AROMI study

AIMS

The present acute myocardial infarction (AMI) rule-out strategies are challenged by the late temporal release of cardiac troponin. Copeptin is a non-specific biomarker of endogenous stress and rises early in AMI, covering the early period where troponin is still normal. An accelerated dual-marker rule-out strategy combining prehospital copeptin and in-hospital high-sensitivity troponin T could reduce length of hospital stay and thus the burden on the health care systems worldwide. The AROMI trial aimed to evaluate if the accelerated dual-marker rule-out strategy could safely reduce length of stay in patients discharged after early rule-out of AMI.

METHODS AND RESULTS

Patients with suspected AMI transported to hospital by ambulance were randomized 1:1 to either accelerated rule-out using copeptin measured in a prehospital blood sample and high-sensitivity troponin T measured at arrival to hospital or to standard rule-out using a 0 h/3 h rule-out strategy. The AROMI study included 4351 patients with suspected AMI. The accelerated dual-marker rule-out strategy reduced mean length of stay by 0.9 h (95% confidence interval 0.7-1.1 h) in patients discharged after rule-out of AMI and was non-inferior regarding 30-day major adverse cardiac events when compared to standard rule-out (absolute risk difference -0.4%, 95% confidence interval -2.5 to 1.7; P-value for non-inferiority = 0.013).

CONCLUSION

Accelerated dual marker rule-out of AMI, using a combination of prehospital copeptin and first in-hospital high-sensitivity troponin T, reduces length of hospital stay without increasing the rate of 30-day major adverse cardiac events as compared to using a 0 h/3 h rule-out strategy.

PrehospitaL Ultrasound in Undifferentiated DyspnEa (PreLUDE): a prospective, clinical, observational study

BACKGROUND

Diagnostic uncertainty in patients with dyspnea is associated with worse outcomes. We hypothesized that prehospital point-of-care ultrasound (POCUS) can improve diagnostic accuracy.

METHODS

Prospective observational study of adult patients suffering dyspnea. Prehospital critical care physicians registered a suspected diagnosis based on clinical examination alone, performed POCUS of the heart and lungs, and finally registered suspected diagnoses based on their clinical examination supplemented with POCUS. Pre- and post-POCUS diagnoses were compared to endpoint committee adjudicated diagnoses. The primary outcome was improved sensitivity for diagnosing acute heart failure. Secondary outcomes included other diagnostic accuracy measures in relation to acute heart failure and other causes of dyspnea.

RESULTS

In total, 214 patients were included. The diagnosis of acute heart failure was suspected in 64/214 (30%) of patients before POCUS and 64/214 (30%) patients after POCUS, but POCUS led to reclassification in 53/214 (25%) patients. The endpoint committee adjudicated the diagnosis of acute heart failure in 87/214 (41%) patients. The sensitivity for the diagnosis of acute heart failure was 58% (95% CI 46%-69%) before POCUS compared to 65% (95% CI 53%-75%) after POCUS (p = 0.12). ROC AUC for the diagnosis acute heart failure was 0.72 (95% CI 0.66-0.78) before POCUS compared to 0.79 (0.73-0.84) after POCUS (p < 0.001). ROC AUC for the diagnosis acute exacerbation (AE) of chronic obstructive pulmonary disease (COPD) or asthma was 0.87 (0.82-0.91) before POCUS and 0.93 (0.88-0.97) after POCUS (p < 0.001). A POCUS finding of any of severely reduced left ventricular function, bilateral B-lines or bilateral pleural effusion demonstrated the highest sensitivity for acute heart failure at 88% (95% CI 79%-94%), whereas the combination of all of these three findings yielded the highest specificity at 99% (95% CI 95%-100%).

CONCLUSION

Supplementary prehospital POCUS leads to an improvement of diagnostic accuracy of both heart failure and AE-COPD/-asthma overall described by ROC AUC, but the increase in sensitivity for the diagnoses of acute heart failure did not reach statistical significance. Tailored use of POCUS findings optimizes diagnostic accuracy for rule-out and rule-in of acute heart failure.

TRIAL REGISTRATION

Registered in Clinical Trials, 05.04.2019 (identifier: NCT03905460) https://clinicaltrials.gov/ct2/show/study/NCT03905460?term=NCT03905460&cond=Dyspnea&cntry=DK&draw=2&rank=1 .

Survival and neurological outcome after out-of-hospital cardiac arrest treated with and without mechanical circulatory support

Aim

The aim of this study was to describe the survival and neurological outcome in patients with OHCA treated with and without mechanical circulatory support (MCS).

Methods

This was a retrospective observational cohort study on patients with OHCA admitted to Aarhus University Hospital, Denmark, between January 2015 and December 2019. Kaplan-Meier estimates were used to evaluate 30-day and 30–180-day survival. Cox regression analysis was used to assess the association between covariates and one-year mortality.

Results

Among 1,015 patients admitted, 698 achieved return of spontaneous circulation (ROSC) before admission, 101 patients with refractory OHCA received mechanical circulatory support (MCS) and the remaining 216 patients with refractory OHCA did not receive MCS treatment. Survival to hospital discharge was 47% (478/1015). Good neurological outcome defined as Cerebral Performance Categories 1–2 were seen among 92% (438/478) of the patients discharged from hospital. Median low-flow was 15 [8–22] minutes in the ROSC group and 105 [94–123] minutes in the MCS group. Mortality rates were high within the first 30 days, however; 30–180-day survival in patients discharged remained constant over time in both patients with ROSC on admission and patients admitted with MCS. Advanced age > 70 years (hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.11–3.49), pulseless electrical activity (HR 2.39, 95% CI 1.25–4.60) and asystole HR 2.70, 95% CI 1.25–5.95) as initial rhythms were associated with one-year mortality in patients with ROSC.

Conclusions

Short-term survival rates were high among patients with ROSC and patients receiving MCS. Among patients who survived to day 30, landmark analyses showed comparable 180-day survival in the two groups despite long low-flow times in the MCS group. Advanced age and initial non-shockable rhythms were independent predictors of one-year mortality in patients with ROSC on admission.

Use of Helicopters to Reduce Health Care System Delay in Patients With ST-Elevation Myocardial Infarction Admitted to an Invasive Center

Timely reperfusion in ST-elevation myocardial infarction (STEMI) is essential. This study aimed to evaluate the reduction in system delay (time from emergency medical service [EMS] call to primary percutaneous coronary intervention [PPCI]) in patients with STEMI when using helicopter EMS (HEMS) rather than ground-based EMS (GEMS). This was a retrospective, nationwide cohort study of consecutive patients with STEMI treated with PPCI at 5 PPCI centers in Denmark. Polynomial spline curves were constructed to describe the association between system delay and distance to the PPCI center stratified by transportation mode. A total of 26,433 patients with STEMI were treated with PPCI between January 1, 1999, and December 31, 2016. In 16,436 patients field triaged directly to the PPCI center, the proportion treated within 120 minutes of the EMS call was 75% for those living 0 to 25 km from the PPCI center compared with 65% for all patients transported by GEMS (median transport distance 50 km [interquartile range 23 to 90]) and 64% for all patients transported by HEMS (median transport distance 119 km [interquartile range 99 to 142]). The estimated reduction in system delay owed to using HEMS rather than GEMS was 14, 16, 20, and 29 minutes for patients living 75, 100, 125, and 170 km from a PPCI center. In conclusion, this study confirmed that using HEMS ensures that most patients with STEMI, living up to 170 km from a PPCI center, can be treated within 120 minutes of their EMS call provided they are field triaged directly to the PPCI center.

Temporal Changes in Serum S100B Levels From Prehospital to Early In-Hospital Sampling in Patients Suffering Traumatic Brain Injury

Background

The biomarker S100B is used for the rule-out of intracranial lesions in patients with mild traumatic brain injury (TBI) and is suggested for prehospital use in Europe. Early kinetics of S100B are not exhaustively investigated in human TBI. This post hoc descriptive study of the data from the PreTBI studies aimed to characterize the early temporal changes of S100B using two-sample timepoints.

Materials and Methods

Two consecutive blood samples were taken prehospital and in-hospital after injury and assayed for S100B. The endpoint adjudication of the outcome intracranial lesion was done by the evaluation of electronic medical patient journals. The data were analyzed using descriptive statistics, scatterplots, and temporal changes estimated by the locally weighted scatterplot smoothing (LOWESS) regression line.

Results

A total of 592 adult patients with TBI were included; 566 with Glasgow Coma Scale (GCS) 14-15, 20 with GCS 9-13, and 6 with GCS 3-8. Intracranial lesions were diagnosed in 44/566 (7.4%) of patients. In 90% of patients, S100B concentrations decreased from prehospital to in-hospital sampling. The mean decrease was−0.34 μg/L. S100B concentrations seem to decline already within 60 min. Patients sampled very close to trauma and patients suffering intracranial lesions may express a slight incline before this decline. Temporal changes of S100B did not differ in patients >65 years of age, in antiplatelet/-coagulant treatment, alcohol intoxicated, or suffering extra-cranial injuries.

Conclusion

S100B concentrations may peak earlier than expected from previous studies of temporal changes in human TBI. Patterns of S100B stand robust to parameters stated as limiting factors to the use for early rule-out of intracranial lesions in the current guidelines. Further studies are needed to investigate the ultra-early temporal profiles of other novel TBI biomarkers to assess prehospital applicability and optimal diagnostic performance in TBI.

Implementation and findings on a one-minute sit-stand test for prehospital triage in patients with suspected COVID-19-a pilot project

Introduction

During the initial Coronavirus Disease 2019 (COVID-19) pandemic wave, sparse personal protection equipment made telephone triage of suscpeted COVID-19 patients for ambulance transport necessary. To spare resources, stable patients were often treated and released on-scene, but reports from Italy suggested that some later detoriated. We implemented a prehospital sit-stand test to identify patients in risk for detoriation.

Methods

The test was implemented as part of a new guideline in stable suspected COVID-19 patients younger than 70 years with no risk factors for serious disease triaged by general practitioners to ambulance response in the Central Denmark Region. Data were collected from April 6^th to July 6^th 2020. The primary outcome for this study was the proportion of patients treated with oxygen within 7 days among patients decompensating vs patients not decompensating during the test.

Results

Data on 156 patients triaged to ambulance response by general practioners were analysed. In total 86/156 (55%) were tested with the sit-stand test. Due to off-guideline use of the test, 30/86 (34.8%) were either older than 70 or had risk factors for serious disease. 10/156 (6%) of patients had a positive COVID-19-test. In total, 17/86 (20%) decompensated during the test and of these, 9/17 (53%) were treated with oxygen compared to 2/69 (3%) in patients who did not decompensate (p < 0.001).

Conclusion

In a population suspected of COVID-19 but with a low COVD-19 prevalence, decompensation with the sit-stand test was observed in 20% of patients and was associated with oxygen treatment within 7 days. These findings are hypotheses-generating and suggest that physical exercise testing may be usefull for decision making in emergency settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00605-9.

Chest pain in the ambulance; prevalence, causes and outcome - a retrospective cohort study

BACKGROUND

Chest pain is common in acute ambulance transports. This study aims to characterize and compare ambulance-transported chest pain patients to non-chest pain patients and evaluate if patient characteristics and accompanying symptoms accessible at the time of emergency call can predict cause and outcome in chest pain patients.

METHODS

Retrospective, observational population-based study, including acute ambulance transports. Patient characteristics and symptoms are included in a multivariable risk model to identify characteristics, associated with being discharged without an acute cardiac diagnosis and surviving 30 days after chest pain event.

RESULTS

In total, 10,033 of 61,088 (16.4%) acute ambulance transports were due to chest pain. In chest pain patients, 30-day mortality was 2.1% (95%CI 1.8-2.4) compared to 6.0% (95%CI 5.7-6.2) in non-chest pain patients. Of chest pain patients, 1054 (10.5%) were diagnosed with acute myocardial infarction, and 5068 (50.5%) were discharged without any diagnosis of disease. This no-diagnosis group had very low 30-day mortality, 0.4% (95%CI 0.2-0.9). Female gender, younger age, chronic pulmonary disease, absence of accompanying symptoms of dyspnoea, radiation, severe pain for > 5 min, clammy skin, uncomfortable, and nausea were associated with being discharged without an acute cardiac diagnosis and surviving 30 days after a chest pain event.

CONCLUSION

Chest pain is a common reason for ambulance transport, but the majority of patients are discharged without a diagnosis and with a high survival rate. Early risk prediction seems to hold a potential for resource downgrading and thus cost-saving in selected chest pain patients.

The role of point of care ultrasound in prehospital critical care: a systematic review

Background

In 2011, the role of Point of Care Ultrasound (POCUS) was defined as one of the top five research priorities in physician-provided prehospital critical care and future research topics were proposed; the feasibility of prehospital POCUS, changes in patient management induced by POCUS and education of providers. This systematic review aimed to assess these three topics by including studies examining all kinds of prehospital patients undergoing all kinds of prehospital POCUS examinations and studies examining any kind of POCUS education in prehospital critical care providers.

Methods and results

By a systematic literature search in MEDLINE, EMBASE, and Cochrane databases, we identified and screened titles and abstracts of 3264 studies published from 2012 to 2017. Of these, 65 studies were read in full-text for assessment of eligibility and 27 studies were ultimately included and assessed for quality by SIGN-50 checklists. No studies compared patient outcome with and without prehospital POCUS. Four studies of acceptable quality demonstrated feasibility and changes in patient management in trauma. Two studies of acceptable quality demonstrated feasibility and changes in patient management in breathing difficulties. Four studies of acceptable quality demonstrated feasibility, outcome prediction and changes in patient management in cardiac arrest, but also that POCUS may prolong pauses in compressions. Two studies of acceptable quality demonstrated that short (few hours) teaching sessions are sufficient for obtaining simple interpretation skills, but not image acquisition skills. Three studies of acceptable quality demonstrated that longer one- or two-day courses including hands-on training are sufficient for learning simple, but not advanced, image acquisition skills. Three studies of acceptable quality demonstrated that systematic educational programs including supervised examinations are sufficient for learning advanced image acquisition skills in healthy volunteers, but that more than 50 clinical examinations are required for expertise in a clinical setting.

Conclusion

Prehospital POCUS is feasible and changes patient management in trauma, breathing difficulties and cardiac arrest, but it is unknown if this improves outcome. Expertise in POCUS requires extensive training by a combination of theory, hands-on training and a substantial amount of clinical examinations – a large part of these needs to be supervised.

Electronic supplementary material

The online version of this article (10.1186/s13049-018-0518-x) contains supplementary material, which is available to authorized users.

Dyspnea, a high-risk symptom in patients suspected of myocardial infarction in the ambulance? A population-based follow-up study

BACKGROUND

Systematic management of patients suffering high-risk symptoms is essential in emergency medical services. Patients with chest pain receive algorithm-based work-up and treatment. Though dyspnea is recognized as an independent predictor of mortality, no generally accepted prehospital treatment algorithm exists and this may affect outcome. The objective of this study was to compare mortality in patients suspected of myocardial infarction (MI) presenting with dyspnea versus chest pain in the ambulance.

METHODS

Follow-up study in patients undergoing electrocardiogram-based telemedical triage because of suspected MI in an ambulance in the Central Denmark Region from 1 June 2008 to 1 January 2013. Primary outcome was 30-day mortality. Secondary outcomes were 4-year mortality and mortality rates in subgroups of patients with and without a confirmed MI. Absolute risk differences adjusted for comorbidity, age, systolic blood pressure and heart rate were calculated by a generalized linear regression model.

RESULTS

Of 17,398 patients, 12,230 (70%) suffered from chest pain, 1464 (8%) from dyspnea, 3540 (20%) from other symptoms and 164 (1%) from cardiac arrest. Among patients with dyspnea, 30-day mortality was 13% (CI 12-15) and 4-year mortality was 50% (CI 47-54) compared to 2.9% (CI 2.6-3.2) and 20% (CI 19-21) in patients with chest pain. MI was confirmed in 121 (8.3%) patients with dyspnea and in 2319 (19%) with chest pain. Patients with dyspnea and confirmed MI had a 30-day and 4-year mortality of 21 % (CI 15-30) and 60% (CI 50-70) compared to 5.0% (CI 4.2-5.8) and 23% (CI 21-25) in patients with chest pain and confirmed MI. Adjusting for age, comorbidity, systolic blood pressure and heart rate did not change these patterns.

CONCLUSION

Patients suspected of MI presenting with dyspnea have significantly higher short- and long-term mortality than patients with chest pain irrespective of a confirmed MI diagnosis. Future studies should examine if supplementary prehospital diagnostics can improve triage, facilitate early therapy and improve outcome in patients presenting with dyspnea.

Developing an emergency ultrasound app - a collaborative project between clinicians from different universities

Focused emergency ultrasound is rapidly evolving as a clinical skill for bedside examination by physicians at all levels of education. Ultrasound is highly operator-dependent and relevant training is essential to ensure appropriate use. When supplementing hands-on focused ultrasound courses, e-learning can increase the learning effect. We developed an emergency ultrasound app to enable onsite e-learning for trainees. In this paper, we share our experiences in the development of this app and present the final product.

Systematic training in focused cardiopulmonary ultrasound affects decision-making in the prehospital setting - two case reports

We present two cases from the Helicopter Emergency Medical Services (HEMS) in Denmark, in which prehospital physicians trained in cardiac ultrasound (FATE) disclosed significant pathology that induced a radical change for the critical patient's course.