Immersion pulmonary oedema in a healthy diver not exposed to cold or strenuous exercise

Abstract

In healthy divers, the occurrence of immersion pulmonary oedema (IPE) is commonly caused by contributory factors including strenuous exercise, cold water and negative-pressure breathing. Contrary to this established paradigm, this case reports on a 26-year-old, well-trained combat swimmer who succumbed to acute IPE during static immersion in temperate (21°C) water, while using a front-mounted counterlung rebreather. The incident occurred during repeated depth-controlled ascent practice at the French military diving school. It was discovered that the diver had attempted to stop any gas leakage into the system by over-tightening the automatic diluent valve (ADV) (25th notch of 27) during the dive, thus causing a high resistance to inspiratory flow. The ventilatory constraints imposed by this ADV setting were assessed as a 3.2 Joules·L⁻¹ inspiratory work of breathing and -5 kPa (-50 mbar) transpulmonary pressure. This report confirms the key role of negative pressure breathing in the development of interstitial pulmonary oedema. Such a breathing pattern can cause a lowering of thoracic, airway and interstitial lung pressure, leading to high capillary pressure during each inspiration. Repetition of the diving drills resulted in an accumulation of interstitial lung water extravasation, causing pathological decompensation and proven symptoms.

Immersion pulmonary oedema: a cardiological perspective

“…The same group also described a special forces trainee aged 26 years who had IPE with a front-mounted counter-lung rebreather. 31 The authors demonstrated that when in a head up position in the water with the automatic diluent valve adjusted as the diver had done, he was breathing against a negative pressure.…”

Broad individual immersion-scattering of respiratory compliance likely substantiates dissimilar breathing mechanics

“…We observed that after 30 min of controlled immersed exercising with identical dive-breathing devices, (i) the number of ultrasound lung comet tails was substantially higher in some subjects and (ii) the work of breathing was also markedly different between the subjects 16 . In addition, the number of lung comet tails, an indicator of the amount of extravascular lung fluid, correlated with the amount of work of breathing (WOB) and with markers of right heart congestion and of right/left ventricular imbalance 16 – 18 .…”

Selected Risks of the Decompression Process, Part II: Analysis of Selected Types of Risk

“…In addition to the occurrence of symptoms of DCS and central oxygen toxicity CNSyn 13 , the inherent R risks considered related to:  incorrect composition of the breathing mix,  workload,  exposure to low temperature,  loss of oxygen supply,  increase in water surface roughness.…”

“…French experience shows that the use of Nx-SCR CRABE SCUBA for MCM operations in shallow waters VSW may lead to the occurrence of pulmonary oedema accompanied by dyspnoea during the dive and later may lead to the appearance of fluid in the lungs or even death. This is due to the effect of negative pressure in the breathing space of the diving apparatus accompanying the expenditure of considerable effort and exposure to cold [12,13]. This may also be exacerbated by excessive hydration [14,15].…”