title: Complement activation in divers after repeated air/heliox dives and its possible relevance to DCS.
abstract: Plasma levels of the anaphylatoxin C5a were measured in 19 divers performing repeated air dives. Blood samples were collected immediately before the first dive and 2 h after the first and the second or third dive. Serum obtained at the same times was subjected to complement activation in vitro by air bubbles. Six divers developed symptoms of decompression sickness (DCS). Most intravascular bubbles were observed in divers with the lowest plasma levels of C5a. Postdive plasma levels of C5a did not increase compared with predive levels, nor were postdive levels significantly different after two or three dives compared with the first dive. Repeated dives did not influence the amounts of C5a generated in vitro. Neither plasma levels of C5a nor C5a generated in vitro were significantly different in divers who experienced symptoms of DCS vs. divers without symptoms of DCS. We conclude that plasma level of C5a and measurement of C5a generation in vitro cannot be used to predict DCS.
authors.affiliation: Section for Extreme Work Environments, Sintef Unimed, University Medical Centre, Trondheim, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Hjelde
authors.forename: K
authors.initials: K
authors.lastname: Bergh
authors.forename: A O
authors.initials: AO
authors.lastname: Brubakk
authors.forename: O J
authors.initials: OJ
authors.lastname: Iversen
mesh_terms: D000328:Adult; D000388:Air; D003167:Complement Activation; D015936:Complement C5a / Q000032:analysis; D003665:Decompression Sickness / Q000097:blood / Q000209:etiology*; D004242:Diving; D004492:Edetic Acid / Q000494:pharmacology; D005740:Gases / Q000097:blood; D006371:Helium; D006801:Humans; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010100:Oxygen
chemical_list: D005740:Gases; D006371:Helium; C038949:heliox; D015936:Complement C5a; D004492:Edetic Acid; D010100:Oxygen