Swimming-induced pulmonary edema: current perspectives

Symptom Duration, Recurrence, and Long-Term Effects of Swimming-Induced Pulmonary Edema: A 30-Month Follow-Up Study

BACKGROUND

Swimming-induced pulmonary edema (SIPE) has been reported to subside within 24 to 48 h, but comprehensive follow-up studies on symptom duration and long-term effects are missing.

RESEARCH QUESTION

What are the symptom duration, recurrence, and long-term effects of SIPE?

STUDY DESIGN AND METHODS

A follow-up study was conducted, based on 165 cases of SIPE from Sweden's largest open-water swimming event with 26,125 individuals participating during 2017-2019. Data on patient characteristics, clinical findings, and symptoms were collected at admission. Telephone interviews at 10 days and 30 months were performed to explore symptom duration, recurrence of SIPE symptoms, need for medical evaluation, and long-term effects of self-assessed general health and physical activity level.

RESULTS

Follow-up at 10 days was performed for 132 cases and at 30 months for 152 cases. Most of the patients were women, and their mean age was 48 years. At the 10-day follow-up, symptom duration > 2 days after the swimming race was reported by 38%. The most common symptoms were dyspnea and cough. In patients at 30-month follow-up, recurrence of respiratory symptoms during open-water swimming was reported by 28%. In multivariable logistic regression, asthma was independently associated with both symptom duration > 2 days and recurrence of SIPE symptoms (P = .045 and P = .022, respectively). Most participants reported equal or improved general health (93%) and physical activity level (85%) after experiencing SIPE, but 58% had not swum in open water since the event.

INTERPRETATION

The present large cohort study challenges the established hallmark of SIPE symptom duration < 48 h, whereas SIPE recurrence was in the previously reported range. At 30 months, most patients reported unchanged self-assessed general health and physical activity level. These findings add to our understanding of the course of SIPE and can provide evidence-based information to swimmers and health care professionals.

Pulmonary Physiology and Medicine of Diving

Pulmonary physiology is significantly altered during underwater exposure, as immersion of the body and increased ambient pressure elicit profound effects on both the cardiovascular and respiratory systems. Thoracic blood pooling, increased breathing gas pressures, and variations in gas volumes alongside ambient pressure changes put the heart and lungs under stress. Normal physiologic function and fitness of the cardiovascular and respiratory systems are prerequisites to safely cope with the challenges of the underwater environment when freediving, or diving with underwater breathing apparatus. Few physicians are trained to understand the physiology and medicine of diving and how to recognize or manage diving injuries. This article provides an overview of the physiologic challenges to the respiratory system during diving, with or without breathing apparatus, and outlines possible health risks and hazards unique to the underwater environment. The underlying pathologic mechanisms of dive-related injuries are reviewed, with an emphasis on pulmonary physiology and pathophysiology.

Atypical distally distributed cutis marmorata decompression sickness associated with unconventional use of thermal protection in a diver with persistent foramen ovale

Cutis marmorata is a mottled, marbling, livedoid rash caused by vascular inflammation and congestion in cutaneous decompression sickness. It may occur during or after ascent due to the formation of bubbles from dissolved nitrogen accumulated throughout the dive. It is strongly associated with the presence of right to left shunts, particularly persistent (patent) foramen ovale (PFO). We report a case of cutis marmorata decompression sickness of an unusual pattern associated with unconventional use of thermal protection (a 'shorty' wetsuit worn over full suit) by a diver with a PFO. The patient also had neurological manifestations of decompression sickness. The distal lower limb pattern of involvement favours the hypothesis that cutis marmorata in humans is likely to be due to bubbles in the skin itself and/or adjacent tissues rather than cerebrally mediated.

Myocardial oedema in the setting of immersion pulmonary oedema - Cause or effect?

Immersion pulmonary oedema (IPE) is an under-reported and poorly understood phenomenon thought to be related to exercise-induced haemodynamic changes while submersed in water. Previous work has demonstrated reversible myocardial dysfunction during acute episodes. We present a case of IPE with concomitant, transient, left ventricular myocardial oedema characterised via MRI. This is a novel finding and may be evidence of left ventricular strain due to pressure overload or secondary to a subclinical myocarditis.

An Unusual Presentation of Pulmonary Edema During an Ice Dive at Altitude

Military diving operations occur in a wide range of austere environments, including high-altitude environments and cold weather environments; however, rarely do both conditions combine. Ice diving at altitude combines the physiologic risks of diving, a hypothermic environment, and a high-altitude environment all in one. Careful planning and consideration of the potential injuries and disease processes affiliated with the aforementioned physiologic risks must be considered. In this case report, we describe a Navy diver who became obtunded secondary to hypoxia during an ice dive at 2,987 m (9,800 ft) elevation and was subsequently diagnosed with high-altitude pulmonary edema. Further consideration of the environment, activities, and history does not make this a clear case, and swimming-induced pulmonary edema which physiologically possesses many overlaps with high-altitude pulmonary edema may have contributed or been the ultimate causal factor for the diver's acute response.

Case Series of Triathletes with Takotsubo Cardiomyopathy Presenting with Swimming-Induced Pulmonary Edema

Objectives

To report three cases of triathletes who presented with swimming-induced pulmonary edema (SIPE) following water immersion. They were subsequently diagnosed with Takotsubo cardiomyopathy (TCM).

Design

Retrospective case series.

Method

All cases were recreational athletes competing in mass participation triathlons between June 2018 and 2019. They were initially managed by the event medical team and subsequently at the local tertiary level hospital. Written consent was gained from all the subjects.

Results

The three triathletes were aged between 50 and 60 years, two were females, and all presented with acute dyspnoea on exiting the water. Two also presented with chest pain and haemoptysis. A diagnosis of SIPE was suspected by the medical event team on initial presentation of low oxygen saturations and clinical signs of pulmonary oedema. All were transferred to the local emergency department and had signs of pulmonary oedema on chest radiographs. Further investigations led to a diagnosis of TCM with findings of T wave inversion in anterolateral electrocardiogram leads and apical hypokinesia on transthoracic echocardiogram and unobstructed coronary arteries.

Conclusions

This case series presents triathletes diagnosed with SIPE and TCM following the open water swim phase. It is unclear whether the myocardial dysfunction contributed to causation of SIPE or was the result of SIPE. Mass participation race organizers must be prepared that both SIPE and TCM can present in this population. Those presenting with an episode of SIPE require prompt evaluation of their cardiac and pulmonary physiology. Further research is required to ascertain the exact nature of the relationship between TCM and SIPE.

Swimming-Induced Pulmonary Edema: Evaluation of Prehospital Treatment With CPAP or Positive Expiratory Pressure Device

BACKGROUND

Swimming-induced pulmonary edema (SIPE) occasionally occurs during swimming in cold open water. Although optimal treatment for SIPE is unknown, non-invasive positive pressure ventilation (NPPV) is an option for prehospital treatment.

RESEARCH QUESTION

Is NPPV a feasible and safe prehospital treatment for SIPE, and which outcome measures reflect recovery after treatment?

STUDY DESIGN AND METHODS

A prospective observational study was conducted at Vansbrosimningen, Sweden's largest open water swimming event, from 2017 through 2019. Swimmers with a diagnosis of SIPE and with peripheral oxygen saturation (Spo2) of ≤ 95%, persistent respiratory symptoms, or both were eligible for the study. NPPV was administered on site as CPAP by facial mask or as positive expiratory pressure (PEP) by a PEP device. Discharge criteria were Spo2 of > 95% and clinical recovery. Four outcome measures were evaluated: Spo2, crackles on pulmonary auscultation, pulmonary edema on lung ultrasound (LUS), and patient-reported respiratory symptoms.

RESULTS

Of 119 treated individuals, 94 received CPAP, 24 received treatment with a PEP device, and one required tracheal intubation. In total, 108 individuals (91%) were discharged after NPPV for a median of 10 to 20 min and 11 individuals (9%) required hospital transfer. NPPV resulted in increased Spo2 from a median of 91% to 97% (P < .0001) together with improvement of six patient-reported respiratory symptoms (median numerical rating scales, 1-7 to 0-1; P < .0001). No significant decrease in auscultation of crackles (93% vs 87%; P = .508) or pulmonary edema on LUS (100% vs 97%; P = .500) was seen during NPPV treatment.

INTERPRETATION

NPPV administered as CPAP or via a PEP device proved feasible and safe as prehospital treatment for SIPE with a vast majority of patients discharged on site. Spo2 and patient-reported respiratory symptoms reflected recovery after treatment, whereas pulmonary auscultation or LUS findings did not.

Immersion pulmonary oedema in a triathlete - a diagnostic challenge in sports cardiology

Immersion pulmonary oedema, also referred to as swimming-induced pulmonary oedema, is a form of pulmonary oedema which usually occurs during swimming in cold water. The condition is most common in triathlon athletes; it was first reported in military divers. The main symptoms include acute dyspnoea, cough, and occasionally haemoptysis, which usually subside within approximately 48 hours. The pathomechanism is not fully understood, but oedema is suspected to be due to an increased systemic vascular resistance that overloads the left ventricle. The diagnostic process can be challenging and require multiple stages to rule out a number of other possible conditions. In view of the circumstances in which incidents typically occur, immersion pulmonary oedema poses an immediate life threat to individuals involved in selected forms of physical activity, where survival is often determined by appropriate training of medical services.

Incidence of Swimming-Induced Pulmonary Edema: A Cohort Study Based on 47,600 Open-Water Swimming Distances

Background

Despite increasing awareness of swimming-induced pulmonary edema (SIPE), large population-based studies are lacking and the incidence is unknown.

Research Question

What is the incidence of SIPE in a mixed group of competitive and recreational swimmers during a large open-water swimming event?

Methods

In four consecutive years (2016-2019), a prospective cohort study was conducted during Sweden’s largest open-water swimming event, Vansbrosimningen. All swimmers seeking medical care with acute respiratory symptoms were eligible for the study. SIPE diagnosis was based on clinical findings in 2016 and 2017 and pulmonary edema assessed by lung ultrasound in 2018 and 2019. Data on patient characteristics, clinical findings, and information about the race were collected.

Results

Based on 47,573 consecutive swimming distances, 322 patients with acute respiratory symptoms (0.68%; CI, 0.61%-0.75%) were treated at the mobile medical unit. Of these, 211 patients (0.44%; CI, 0.39%-0.51%) received a diagnosis of SIPE. The annual incidence of SIPE was 0.34%, 0.47%, 0.41%, and 0.57%, respectively, from 2016 through 2019. Most patients diagnosed with SIPE were women (90%), despite about equal percentages of men and women participating (47% men and 53% women). The incidence of SIPE overall was 0.75% in women and 0.09% in men. The incidence increased with age, from 0.08% in the youngest age group (18-30 years) to 1.1% in the oldest age group (≥ 61 years). Based on multiple logistic regression analysis, the adjusted odds for SIPE occurring was 8.59 times higher for women compared with men and 12.74 times higher for the oldest age group compared with the youngest age group.

Interpretation

The incidence of SIPE over 4 years during a large open-water swimming event in Sweden was 0.44%. The incidence was higher in women than in men and increased with age.

Swimming-Induced Pulmonary Edema in an Active-Duty Female Triathlete

Swimming-induced pulmonary edema (SIPE) is a noncardiogenic form of acute pulmonary edema infrequently described in the general military literature. Its pathophysiology is poorly understood. Treatment is supportive. Knowledge of SIPE is important for the military physician and should remain a top differential for any patient presenting with acute pulmonary edema following a water sport. This is the case of a patient with SIPE occurring during the swim portion of a Half Ironman Triathlon.

Swimming exercise transiently decrease lung diffusing capacity in elite swimmers

BACKGROUND

Swimmers have larger lungs and a higher diffusion capacity than other athletes, but it remains unknown whether swimming exercise changes lung diffusing properties. This study aimed to evaluate modifications in pulmonary alveolar-capillary diffusion after swimming exercise.

METHODS

The participants were 21 elite level swimmers, including 7 females and 14 males, with a training volume of 45-70 kilometers of swimming per week. The single-breath method was used to measure the lung diffusing capacity for carbon monoxide (DLCO and the transfer coefficient of the lungs for carbon monoxide (K<inf>CO</inf>) before and after 10 training sessions over 4 weeks along 207 pre- to postevaluations.

RESULTS

Swimming training consistently decreased lung diffusion capacity during the follow-up period, both DL<inf>CO</inf> (44.4±8.1 to 43.3±8.9 mL·min-1·mmHg-1, P=0.047, ŋ²<inf>p</inf>=0.55) and K<inf>CO</inf> (5.92±0.79 to 5.70±0.81 mL·min-1·mmHg-1·L-1, P=0.003, ŋ²<inf>p</inf>=0.75).

CONCLUSIONS

Elite swimmers experience a subclinical impairment in lung diffusing capacity after swimming exercise, but the stress caused by swimming on the lungs and the acute reduction in DL<inf>CO</inf> does not lead to physiological dysfunction.

Snorkeling Induced Pulmonary Edema: A Case Report and Review of the Literature

Swimming-induced pulmonary edema (SIPE), also called immersion pulmonary edema (IPE), is a medical condition seen in various water-based activities such as scuba diving, swimming, aqua jogging, triathlete competition and snorkeling. It occurs when transcapillary filtration of low protein fluid collects in the lungs, in the absence of water aspiration during an aquatic activity, causing acute dyspnea, cough and/or hemoptysis. The hallmark of this entity is the complete resolution of symptoms within 48 hours. SIPE in snorkeling is an under-reported and understudied subject. The true prevalence of SIPE is unknown with an estimated range from 1.8-60% among combat swimmers trainee and 1.4% in triathletes. Recent developments have been done in elucidating the pathophysiology of SIPE with regards to pulmonary capillary pressure so that the predisposing factors and potential causes can be targeted. SIPE can be a potentially life-threatening condition, which needs to be recognized by the swimmers, divers, supervising physicians in order to diagnose and manage it promptly. We report a rare case of SIPE in snorkeling which presented with acute respiratory symptoms and managed with supportive measures in the hospital.