Background:

It has been risen a warning related with immersion pulmonary edema (IPE) associated to the use of the semi-closed rebreather circuit CRABE. This is a diving equipment broadly used among NATO countries, including Spanish Navy.

Aim:

to evaluate the safety of semi-closed circuit CRABE in military use, particularly in its association with IPE.

Methods:

This is a prospective study, in which 14 male active navy divers from 1st Mine Countermeasures (MCM) Squadron (Cartagena) were recruited. The diving protocol was programmed with increasing bottom times, from 30 to 120 minutes, at 10 meters shallow water. All divers underwent to physical examination for IPE symptoms screening before and after dives. At 120 minutes bottom time, a pulmonary and cardiac echography as well as blood sampling were also performed before and after dives. Serum levels of NT pro-BNP were assessed.

Results:

All diver completed successfully all dives. No diver developed any symptom related to respiratory compromise or IPE after dives. At 120 minutes bottom time phase, 9 out of 14 (64.2%) divers developed ultrasound lung comets (ULC). This number is below the cut-off point for pulmonary edema diagnosis. There was not NT pro-BNP levels above the clinically recommended cut-off point for heart failure diagnosis.

Conclusions:

The use of semi-closed circuit rebreather CRABE was not associated to IPE.