Predicting outcome for ambulance patients with dyspnea: a prospective cohort study.

OBJECTIVE: To validate the discrimination and classification accuracy of a novel acute dyspnea scale for identifying outcomes of out-of-hospital patients with acute dyspnea. METHODS: Prospective observational population-based study in the North Denmark Region. We included patients from July 1, 2017 to September 24, 2019 assessed as having acute dyspnea by the emergency dispatcher or by emergency medical services (EMS) personnel. Patients rated dyspnea using the 11-point acute dyspnea scale. The primary outcomes were hospitalization >2 days, ICU admission within 48 hours of ambulance run, and 30-day mortality. We used 5-fold cross-validation and area under receiver operating curves (AUC) to assess predictive properties of the acute dyspnea scale score alone and combined with vital data, age, and sex. RESULTS: We included 3144 EMS patients with reported dyspnea. Median acute dyspnea scale score was 7 (interquartile range 5 to 8). The outcomes were: 1966 (63%) hospitalized, 164 (5%) ICU stay, and 224 (9%) died within 30 days of calling the ambulance. The acute dyspnea scale score alone showed poor discrimination for hospitalization (AUC 0.56, 95% confidence intervals: 0.54-0.58), intensive care unit admission (0.58, 0.53-0.62), and mortality (0.46, 0.41-0.50). Vital signs (respiratory rate, blood oxygen saturation, blood pressure, and heart rate) showed similarly poor discrimination for all outcomes. The combination of [vital signs + acute dyspnea scale score] showed better discrimination for hospitalization, ICU admission, and mortality (AUC 0.71-0.72). Patients not able to report an acute dyspnea scale score worse outcomes on all parameters. CONCLUSION: The dyspnea scale showed poor accuracy and discrimination when predicting hospitalization, stay at intensive care unit, and mortality on its own. However, the dyspnea scale may be beneficial as performance measure and indicator of out-of-hospital care.

Patient experience of severe acute dyspnoea and relief during treatment in ambulances: a prospective observational study.

BACKGROUND: Acute dyspnoea is common among ambulance patients, but little is known of the patients' experience of symptom. We aimed to investigate ambulance patients initial perceived intensity of acute dyspnoea, and whether they experienced relief during prehospital treatment. Furthermore, to investigate the validity and feasibility of using a subjective dyspnoea score in the ambulance, and its association with objectively measured vital signs. METHODS: We performed a prospective observational study in the North Denmark Region from 1. July 2017 to 30. March 2019. We studied patients over the age of 18 to whom an ambulance was dispatched. Patients with acute dyspnoea assessed either at the emergency call or by ambulance professionals on scene were included. Patients were asked to assess dyspnoea on a 0 to 10 verbal numeric rating scale at the primary contact with the ambulance personnel and immediately before release at the scene or arrival at the hospital. Patients received usual prehospital medical treatment. We used visual inspection and Wilcoxon matched-pairs signed-ranks test, to assess dyspnoea scores and change hereof. Scatterplots and linear regression analyses were used to assess associations between the dyspnoea score and vital signs. RESULTS: We included 3199 patients with at least one dyspnoea score. Of these, 2219 (69%) had two registered dyspnoea scores. The initial median dyspnoea score for all patients was median 8 (interquartile range 6-10). In 1676 (76%) of patients with two scores, the first score decreased from 8 (6-9) to 4 (2-5) during prehospital treatment. The score was unchanged for 370 (17%) and increased for 51 (2%) patients. Higher respiratory rate, blood pressure, and heart rate was seen with higher dyspnoea scores whereas blood oxygen saturation lowered. CONCLUSIONS: We found that acute dyspnoea scored by ambulance patients, was high on a verbal numerical rating scale but decreased before arrival at hospital, suggesting relief of symptoms. The acute dyspnoea score was statistically associated with vital signs, but of limited clinical relevance; this stresses the importance of patients' experience of symptoms. To this end, the dyspnoea scale appears feasible in the prehospital setting.

Completeness in the recording of vital signs in ambulances increases over time.

INTRODUCTION: In 2006, the North Denmark Region implemented the electronic prehospital patient medical record (PPR), amPHI, in the region's prehospital emergency medical service. In 2015, a new nationwide version was implemented. Our aim was to investigate the completeness and correctness of registrations of vital sign data in the PPR after the initial introduction and after the implementation of the new PPR version. METHODS: This was a descriptive registry-based study including patients to whom an ambulance was dispatched after an emergency call in the North Denmark Region in the periods 2007-2014 and 2016-2017. We examined vital sign data defined as blood pressure (BP), heart rate (HR), blood oxygen saturation (SpO2), respiratory rate (RR), Glasgow Coma Scale (GCS) score and numeric rating scale (NRS) for pain. We defined incorrect vital sign values according to clinical plausibility. We used a trend analysis and Pearson's χ2. RESULTS: We included 253,169 PPRs. The proportion of PPR with registration of vital signs from 2007-2014 compared with 2016-2017 was BP: 73-86%, 81-82%; HR: 76-88%, 82-83%; SpO2: 72-85%, 82-83%; RR: 34-82%, 77-79%; GCS score: 54-92%, 81-84%; NRS for pain: 0-16%, 24-26%. The increase from 2007-2014 and 2016-2017 was significant as were the differences between 2014 and 2016. We found few defined outliers (0.5%). CONCLUSIONS: The completeness of registration increased gradually but decreased slightly after implementation of the new version. A high completeness combined with few implausible outliers and concordance indicate correctness of the vital sign registrations. FUNDING: none. TRIAL REGISTRATION: Approval for the use of data was given by the medical director of the Emergency Medical Services, the North Denmark Region.

Prehospital treatment with continuous positive airway pressure in patients with acute respiratory failure: a regional observational study.

BACKGROUND: Patients with acute respiratory failure are at risk of deterioration during prehospital transport. Ventilatory support with continuous positive airway pressure (CPAP) can be initiated in the prehospital setting. The objective of the study is to evaluate adherence to treatment and effectiveness of CPAP as an addition to standard care. METHODS: In North Denmark Region, patients with acute respiratory failure, whom paramedics assessed as suffering from acute cardiopulmonary oedema, acute exacerbation of chronic obstructive pulmonary disease or asthma were treated with CPAP using 100 % O2 from 1 March 2014 to 3 May 2015. Adherence to treatment was evaluated by number of adverse events and discontinuation of treatment. Intensive care admissions and mortality were reported in this cohort. Effectiveness was evaluated by changes in peripheral oxygen saturation (SpO2) and respiratory rate during transport and compared to a historical control (non-CPAP) group treated with standard care only. Values were compared by hypothesis testing and linear modelling of SpO2 on arrival at scene and ΔSpO2 stratified according to treatment group. RESULTS: In fourteen months, 171 patients were treated with CPAP (mean treatment time 35 ± 18 min). Adverse events were reported in 15 patients (9 %), hereof six discontinued CPAP due to hypotension, nausea or worsening dyspnoea. One serious adverse event was reported, a suspected pneumothorax treated adequately by an anaesthesiologist called from a mobile emergency care unit. Among CPAP patients, 45 (27 %) were admitted to an intensive care unit and 24 (14 %) died before hospital discharge. The non-CPAP group consisted of 739 patients. From arrival at scene to arrival at hospital, CPAP patients had a larger increase in SpO2 than non-CPAP patients (87 to 96 % versus 92 to 96 %, p < 0.01) and a larger decrease in respiratory rate (32 to 25 versus 28 to 24 breaths/min, p < 0.01). In a linear model, CPAP was superior to non-CPAP in patients with initial SpO2 ≤90 % (p < 0.05). One CPAP patient (0.6 %) and eight non-CPAP patients (1.1 %) were intubated in the prehospital setting. DISCUSSION: The study design reflects the daily prehospital working environment including long transport timesand paramedics educated in treating symptoms of acute respiratory failure, rather than treating one specific diagnosis. The study population was included consecutively and few patients were lost to follow-up. However, the study was too small to allow assessment of any effect of prehospital CPAP on mortality, nor could the effectiveness in specific disease conditions be examined. CONCLUSIONS: In an emergency medical service including physician backup, adherence to CPAP treatment administered by paramedics was high and treatment was effective in patients with acute respiratory failure.