BACKGROUND: Ultrasound lung comets (ULCs) detected by chest sonography are a 
simple, noninvasive, semiquantitative sign of increased extravascular lung 
water. Pulmonary edema may occur in elite apnea divers, possibly triggered by 
centralization of blood flow from the periphery to pulmonary vessels. We 
assessed the prevalence of ULCs in top-level breath-hold divers after immersion.
METHODS: We evaluated 31 consecutive healthy, top-level, breath-hold divers (10 
female, 21 male; age 31 +/- 5 years) participating in a yearly international 
apnea diving contest in Sharm-el-Sheik, Egypt, November 1 to 3, 2007. We 
performed chest and cardiac sonography with a transthoracic probe (2.5-3.5 MHz, 
Esaote Mylab) in all divers, both on the day before and 10 +/- 9 minutes after 
immersion. In a subset of 4 divers, chest scan was also repeated at 24 hours 
after immersion. ULCs were evaluated on the anterior and posterior chest at 61 
predefined scanning sites. An independent sonographer, blind to both patient 
identity and status (pre- or post-diving), scored ULCs.
RESULTS: Diving depth ranged from 31 to 112 m. Duration of immersion ranged from 
120 to 225 seconds. The ULC score was 0.5 +/- 1.5 at baseline and 13 +/- 21 
after diving (P = .012). At individual patient analysis, ULCs appeared in 14 
athletes (45%) after diving. Of these 14 athletes, 4 were asymptomatic, 6 showed 
aspecific symptoms with transient loss of motor control ("Samba"), 2 had 
palpitations with frequent premature ventricular contractions, and 2 had 
persistent cough with hemoptysis and pulmonary crackles. In a subset of 4 
athletes with post-diving ULCs in whom late follow-up study also was available, 
chest sonography findings fully normalized at 24 hours of follow-up.
CONCLUSION: In top-level breath-hold divers, chest sonography frequently reveals 
an increased number of ULCs after immersion, indicating a relatively high 
prevalence of (often subclinical) reversible extravascular lung water 
accumulation.