Increased Extravascular Lung Water in Asymptomatic Open-water Swimmers

Recruiting

• Conditions: Pulmonary Edema - Acute; Extravascular Lung Water

• Registration Number: NCT06984120
• Lead Sponsor: Dalarna County Council, Sweden

Brief Summary

Previous studies suggest that increased extravascular lung water might be found in open water swimmers without respiratory symptoms. This study aims to investigate a large number of asymptomatic individuals after an open-water swimming race to assess the prevalence of increased extravascular lung water in asymptomatic open-water swimmers.

Detailed Description

Swimming-induced pulmonary edema (SIPE) can occur during open-water swimming. The pathophysiological mechanisms are still partly unknown, but central pooling of blood volume and peripheral vasoconstriction have been suggested as important factors. SIPE is characterized by acute onset of dyspnea and cough, sometimes with excessive sputum and hemoptysis. The condition usually resolves spontaneously, but medical attention can be required in more severe cases.

Previous studies suggest that SIPE is diagnosed by clinical symptoms, decreased peripheral oxygen saturation and signs of pulmonary edema on lung ultrasound. Interestingly, signs of increased extravascular lung water have been found in divers without respiratory symptoms. There are no similar studies regarding open-water swimmers.

This study aims to investigate a large number of swimmers without respiratory symptoms after finishing an open-water swimming race. Prevalence and amount of increased extravascular lung water after swimming will be assessed by lung ultrasound. In addition, individual baseline factors and information about the race associated with increased extravascular lung water will be evaluated. This study will provide better understanding of the pathophysiological mechanism of SIPE.

Study Timeline

• Status Verified: 2025-05
• Study First Submitted: 2025-05-14
• Study First Submitted QC: 2025-05-14
• Study First Posted: 2025-05-22
• Last Update Submitted: 2025-06-23
• Last Update Posted: 2025-06-26
• Study Start: 2025-06-29
• Primary Completion: 2028-12-30
• Study Completion: 2028-12-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 570

Inclusion Criteria

• Completion of an open-water swimming race during the "Vansbrosimningen" open-water swimming event
• No respiratory symptoms (dyspnea and/or cough) during or right after the race
• Age ≥ 18 years

Exclusion Criteria

• Presence of respiratory symptoms (dyspnea and/or cough) during or right after the swimming race
• Declines participation

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Interstitial syndrome assessed by lung ultrasound (yes/no)	Within 1 hour after termination of swimming	Four chest regions for both lungs are scanned by lung ultrasound; a positive region defined by the presence of three or more B-line artifacts. Bilateral or unilateral presence of two or more positive regions define positive interstitial syndrome.
Number of regions presenting B-lines on lung ultrasound	Within 1 hour after termination of swimming	Four chest regions for both lungs are scanned by lung ultrasound; a positive region defined by the presence of three or more B-line artifacts. Assessment of the total number of positive regions.
Absolute number of B-lines on lung ultrasound	Within 1 hour after termination of swimming	Four chest regions for both lungs are scanned by lung ultrasound; the absolute number of B-lines in each region is counted.

Secondary Outcome Measures

Name	Time	Method
Number of regions presenting B-lines on lung ultrasound	At follow up within 4 hours after termination of swimming	Four chest regions for both lungs are scanned by lung ultrasound; a positive region defined by the presence of three or more B-line artifacts. Assessment of the total number of positive regions. Performed in individuals with signs of increased extravascular lung water after swimming.
Presence of crackles on lung auscultation (yes/no)	Within 1 hour after termination of swimming	Presence of crackles on lung auscultation
Body temperature	At baseline 2-4 hours before swimming.	Body temperature measured by ear thermometer
Interstitial syndrome assessed by lung ultrasound (yes/no)	At follow up within 4 hours after termination of swimming	Four chest regions for both lungs are scanned by lung ultrasound; a positive region defined by the presence of three or more B-line artifacts. Bilateral or unilateral presence of two or more positive regions define positive interstitial syndrome. Performed in individuals with signs of increased extravascular lung water after swimming.
Absolute number of B-lines on lung ultrasound	At baseline 2-4 hours before swimming	Four chest regions for both lungs are scanned by lung ultrasound; the absolute number of B-lines in each region is counted.
Perceived exertion during swimming	Within 1 hour after termination of swimming	Perceived exertion during the swimming race measured by "Borg rating of perceived exertion scale". Values on the scale range from a minimum value of 6 (no exertion) to a maximum value of 20 (maximal exertion).
Peripheral oxygen saturation	At baseline 2-4 hours before swimming.	Peripheral oxygen saturation measured by non-invasive pulse oxymetry

Trial Locations

Locations (1)

Center of Clinical Research Dalarna; 🇸🇪 Falun, Sweden