Investigation into the clinical use of the non-invasive estimation of haemodynamic performance in timecritical patients in Emergency Departments.

Abstract

Introduction: Emergency departments (EDs) serve as the frontline of acute medical care, where rapid and accurate assessment of patients is critical for determining the appropriate level of intervention. Vital signs recorded at triage are essential for assessing a patient's immediate health status and helping clinicians prioritise care. However, traditional vital signs alone may not always provide a comprehensive picture of a patient's cardiovascular function. Recent advances in non-invasive cardiovascular monitoring, specifically Ultrasonic Cardiac Output Monitoring (USCOM), offer new possibilities for enhancing patient assessment at triage. USCOM provides detailed haemodynamic parameters, such as cardiac power (CP), which could potentially improve the accuracy of outcome predictions in ED patients. This study aimed to evaluate the clinical and predictive value of traditional vital signs and USCOM-derived cardiovascular parameters recorded at triage in ED patients. It compared conventional haemodynamic assessments with USCOM data to determine their association with patient outcomes.

Methods: Two studies were conducted at Liverpool Hospital ED, Sydney. Study 1 was retrospective (May 2018–May 2021), analysing conventional vital signs in adult patients with triage categories 2 and 3. Study 2 was prospective (March 2023–October 2023), focusing on USCOM-derived parameters in similar patient groups.

Results: Study 1 included 116,460 patients and identified several key predictive vital signs for mortality: hypoxia (OR 2.13), abnormal respiratory rate (OR 2.43), bradycardia/tachycardia (OR 1.55), and hypotension (OR 2.60). Age was the strongest predictor, with higher mortality and ICU admission in patients aged 40-65 and over 65. For the second study, we included 409 patients. CP was a strong predictor for ICU (OR 0.28) and hospital admissions (OR 0.11). A decline in cardiovascular function over the first six hours was associated with higher mortality.

Conclusion: This study highlights the importance of triage vital signs in predicting patient outcomes and the potential of USCOM-derived cardiac power to improve risk stratification. Age-specific triage protocols are recommended due to the diminishing predictive value of certain vital signs with age. Future research should validate these findings and explore integrating advanced haemodynamic monitoring into routine practice.