O2 Versus CPAP Treatment Of Patients Undergoing SIPE Therapy (OCTOPUS) (OCTOPUS)

Evaluation of Continous Positive Airway Pressure (CPAP) in Swimming Induced Pulmonary Edema (SIPE) -a Randomized Single-blinded Controlled Study

In swimming induced pulmonary edema (SIPE), there is a lack of knowledge regarding optimal treatment. The present study was designed to assess the benefit of continuous positive airway pressure (CPAP) compared to oxygen as a first line treatment of SIPE in the out-of-hospital environment.

Swimming induced pulmonary edema (SIPE) is an unusual condition affecting otherwise healthy swimmers. SIPE is characterized by acute onset of dyspnea and cough, excessive sputum and occasionally hemoptysis when swimming in open water. The condition usually resolves spontaneously within 48 hours, but may result in serious illness and require emergency care. Case reports describe acute treatment with oxygen alone or in combination with diuretics, beta-agonist-inhalation or continuous positive airway pressure (CPAP). Evidence for optimal treatment strategy is lacking. This study intends to determine whether oxygen alone or applied together with CPAP leads to improvement of oxygen saturation and recovery of patients. The aim is to treat patients on site without involving hospital care. We study a large cohort of approximately 12 000 swimmers during Vansbrosimningen, Sweden's biggest annual open water event with a yearly incidence of SIPE about 0,4%. Adult patients clinically diagnosed with SIPE are randomly assigned in 2 groups receiving treatment during 20 minutes: (1) oxygen 10l/min or (2) oxygen 10l/min and CPAP 7,5 cm H2O. Assessment with outcome measures is taken 10 minutes after treatment. Primary endpoint: oxygen saturation (%) by pulse oxymetry.

Change in peripheral oxygen saturation % (continuous variable) measured by pulse oximetry before and after treatment

Recovery, defined by "peripheral oxygen saturation >95% after treatment" or no recovery, defined by "peripheral oxygen saturation ≤95% after treatment"

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.

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.

Change in absolute number of regions presenting B-lines on lung ultrasound before and after treatment

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. Change in absolute number of regions presenting B-lines on lung ultrasound before and after treatment

Six different patient reported outcome measures assessed by numeric rating scale (NRS) 0-10: cough, sputum, air hunger, breathing effort, tightness in chest, anxiousness. The patients will assess symptoms prior to and after treatment.

admission to hospital within or after a maximal treatment time of 40 minutes followed by 20 min rest.

Inclusion Criteria: clinical diagnosis of swimming induced pulmonary edema (SIPE) with need of acute treatment (oxygen saturation ≤91%) 18 years and older informed consent Exclusion Criteria: declined consent suspected acute coronary syndrome severe asthma diagnosed together with pulmonary edema where beta-agonist-inhalation is needed prior to treatment of pulmonary edema hemodynamic instability or decreased consciousness