This is an analytical cross-sectional study of emergency department patients consulting for dyspnea, chest pain, and undifferentiated shock state; these patients were suspected of acute decompensated heart failure, acute coronary syndrome, and specific types of shock respectively. It was carried out in a tertiary-level university-based hospital in Barranquilla, Colombia. The Ethics Committee and Institutional Research Board approved the protocol (Act 281, November 24th, 2022).

The study was conducted between 2019 and 2022. Patients eligible were adults who visited the emergency department with any of these three chief conditions: acute dyspnea suspicion of acute heart failure; acute chest pain suspicion of acute coronary syndrome; shock state defined as clinical hypoperfusion (altered mental status, long capillary refill time) and/or hypotension (Mean arterial pressure less than 65 mmHg). Inclusion criteria were a POCUS evaluation performed at admission, US findings reported in clinical records, reported initial diagnosis using POCUS alongside usual clinical evaluation, reported discharge (final) diagnosis considering evolution, laboratory parameters, and images. Exclusion criteria were death during the first 24 h of admission, ST-segment elevation ACS, not definitive diagnosis at discharge, in-hospital transfer to another healthcare facility, and not clear diagnosis at entrance.

Patients in the ED with any of the three main complaints underwent a triage classification. Priority was given according to triage. The first medical contact was an emergency physician who took a directed clinical history and physical examination. Patients with acute shortness of breath (defined as dyspnea that began in the last 4 weeks) and a history consistent with congestion (edemas, jugular distension, S3 gallop, hepatojugular reflux) were considered to have acute decompensated heart failure. Patients consulting with cardiac chest pain considered acute coronary syndrome were approached accordingly. Shock patients were treated in a resuscitation room and received intravenous fluids if considered hypovolemic, inotropes if the initial diagnosis was cardiogenic shock, and antibiotics plus cultures if deemed septic shock.

After first medical contact, focused clinical history was taken by the attending internal medicine physician. A thorough physical examination was performed, including Point-of-Care Ultrasound as an extension of the physical evaluation to assure an initial diagnosis. Every patient had an initial diagnosis using clinical history, physical examination, and ultrasound evaluation. After clinical evaluation, a POCUS exam and a decision made, initial treatment was ordered.

In patients with a suspicion of ADHF, diagnostic aids, and interventions included oxygen, intravenous furosemide, chest X-ray, lung ultrasound, cardiac ultrasound, electrocardiogram, natriuretic peptides, etc. Diagnostic aids and interventions for patients with a suspicion of ACS included dual antiplatelet inhibition, sublingual or intravenous nitrates, parenteral anticoagulation, atorvastatin, comprehensive echocardiogram, and troponin assay.

POCUS evaluation was performed using a multiprobe ultrasound machine (Sonoscape Corp. Model S2. Guangdong, China. 2016-3) by the attending internal medicine physician trained in POCUS. Dyspneic patients assessment included BLUE protocol [15] using a linear transducer with a frequency of 5–10 MHz and a phased array with a frequency of 2–5 MHz. B-lines, pleural effusion, and lung consolidation were specific findings at US evaluation. Findings were integrated with clinical symptoms to consider a specific initial diagnosis.

Patients with acute chest pain were evaluated with a focused cardiac ultrasound using a phased array probe with a frequency of 2–5 MHz. In patients with a suspicion of acute coronary syndrome, POCUS analyzed at least three of the four main cardiac views (parasternal long and short axis, apical, and subxiphoid). Eyeball systolic ventricular function, pericardial effusion, and wall motion abnormalities were considered. RUSH protocol [16] was followed in shock patients to rule-in or rule-out specific etiologies such as obstructive causes, cardiogenic shock, vasodilated shock or hypovolemic shock.

Patients were treated according to the initial diagnosis and always after the POCUS exam. Medications, images, and laboratory tests were ordered considering clinical context and up-to-date clinical guidelines. No further ultrasound evaluation was performed during hospitalization.

The internal medicine specialist from the ED did not have any other interaction with the patient or clinical staff in the ICU and general ward. Specialists from these clinical areas were aware of the POCUS initial evaluation.

The final diagnosis was given by the attending physician at discharge in the general ward. This internal medicine specialist oversaw every patient included in the study from in-ward admission until discharge. This diagnosis considered initial evaluation, all laboratory diagnostic work-up, images, and clinical evolution to declare a final and definite diagnosis.

All the information was taken from clinical records. Every variable was drawn from initial clinical history, ultrasound evaluation at admission, and final diagnosis on discharge day.

According to published methods for sample size estimation [17], considering a disagreement probability of 20%, a Cohen’s Kappa of 0.85, and an alfa value of 0.05, the population should be of 192 patients. Moreover, we report sensitivities, specificities, predictive values, and likelihood ratios in each group of patients.

Categorical variables are expressed in absolute and relative frequencies. Continuous variables are expressed in mean and standard deviation, median, and interquartile ranges. The initial diagnosis was compared for agreement with the final diagnosis using Cohen’s kappa statistic in patients with heart failure, chest pain, and shock. A two-sided p value < 0.05 was considered to indicate statistical significance. All statistical analyses were conducted using SPSS version 25.