Ultrasound Investigation Into Swimming Induced Pulmonary Edema in Open Water Swimming Athletes

This research project aims to advance the understanding of the signs of pulmonary edema by evaluating both symptomatic and asymptomatic individuals at triathlons and open water swim events. Ultrasound is being used here as it is a validated tool for the assessment of pulmonary edema and pleural effusion and is highly portable and cost-effective, improving access to imaging in austere and limited-resource medical environments.

Swimming-induced pulmonary edema lacks an abundance of evidence identifying its pathophysiology, as well as information regarding the normal progression of signs and symptoms. Unfortunately, while there are some protocols for identifying patients with symptoms, many times these are too late and symptoms are advanced. Improving the identification of early signs of SIPE may lead to better outcomes, more timely intervention, and an improved understanding of the pathophysiology of the disease.

Use of a high-quality handheld ultrasound to evaluate open-water swimmers for signs of pulmonary edema will contribute to the field in several ways. First, improving knowledge of the signs in both symptomatic and asymptomatic individuals is beneficial to the identification and early treatment of patients. Secondly, utilizing portable imaging technology for novel applications improves utility and may increase access to medical resources in resource-poor environments. Third, by validating this protocol for the evaluation of SIPE, medical professionals who attend to patients who may experience SIPE have improved diagnostic capability to intervene earlier. Literature shows a higher incidence of SIPE in military training recruits, such as Navy Seals, and open-water swimming athletes, both of whom operate in austere and resource-limited environments, and would benefit from improved early diagnostic tools to identify pathology.

Our specific aims are to utilize ultrasound and the BLUE protocol (described below), and acquisition of vital signs, and health history in the medical tent with patients and with a control group of race finishers to identify normal anatomy or pathology. We will compare findings in areas of previous experience, level of fitness, gender, age, wetsuit status, and environmental factors. We will run a statistical analysis to compare our findings and account for the day's environmental factors, race type, history, and physical exam findings.

Swimming Induced Pulmonary Edema (SIPE), is a poorly understood respiratory pathology that can affect individuals without underlying health conditions and can be potentially life-threatening. (Spencer, 2018). SIPE is an immersion pulmonary edema presenting with dyspnea, chest pain, cough, hemoptysis, frothy sputum production, and may result in death. (miller 2011) (Grunig 2017) ( Smart, 2014) (Department of the Navy, 2023). The pathophysiological mechanisms of SIPE are not fully understood but may involve the redistribution of blood centrally during cold water immersion, resulting in elevated pressure in the right-sided intravascular system and a concurrent increase in afterload (Wester 2009). Some individuals with a history of SIPE tend to have increased Mean Pulmonary Artery Pressure (MPAP) and Pulmonary Artery Wedge Pressure (PAWP)with a reduction in these pressures and SIPE incidence after a 50 mg oral dose of sildenafil. Understanding the pathophysiology of SIPE considers its multifaceted causes consisting of environmental, genetic, and predisposing risk factors. (Moon 2016).