title: A comparative evaluation of two decompression procedures for technical diving using inflammatory responses: compartmental versus ratio deco.
abstract: The aim of this study was to compare two decompression procedures commonly adopted by technical divers: the ZH-L16 algorithm modified by 30/85 gradient factors (compartmental decompression model, CDM) versus the 'ratio decompression strategy' (RDS). The comparison was based on an analysis of changes in diver circulating inflammatory profiles caused by decompression from a single dive.
  
  
  
  Fifty-one technical divers performed a single trimix dive to 50 metres' sea water (msw) for 25 minutes followed by enriched air (EAN50) and oxygen decompression. Twenty-three divers decompressed according to a CDM schedule and 28 divers decompressed according to a RDS schedule. Peripheral blood for detection of inflammatory markers was collected before and 90 min after diving. Venous gas emboli were measured 30 min after diving using 2D echocardiography. Matched groups of 23 recreational divers (dive to 30 msw; 25 min) and 25 swimmers were also enrolled as control groups to assess the effects of decompression from a standard air dive or of exercise alone on the inflammatory profile.
  
  
  
  Echocardiography at the single 30 min observation post dive showed no significant differences between the two decompression procedures. Divers adopting the RDS showed a worsening of post-dive inflammatory profile compared to the CDM group, with significant increases in circulating chemokines CCL2 (P = 0.001) and CCL5 (P = 0.006) levels. There was no increase in chemokines following the CDM decompression. The air scuba group also showed a statistically significant increase in CCL2 (P < 0.001) and CCL5 (P = 0.003) levels post dive. No cases of decompression sickness occurred.
  
  
  
  The ratio deco strategy did not confer any benefit in terms of bubbles but showed the disadvantage of increased decompression-associated secretion of inflammatory chemokines involved in the development of vascular damage.
authors.affiliation: Department of Biological, Geological and Environmental Sciences, Translational Physiology and Nutrition Unit, University of Bologna, Via Selmi 3, 40126 Bologna, Italy, enzo.spisni@unibo.it.
authors.forename: Enzo
authors.initials: E
authors.lastname: Spisni
authors.affiliation: Department of Biological, Geological and Environmental, Sciences, University of Bologna, Italy.|Department of Cardiology, Civic Hospital Cecina, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Marabotti
authors.affiliation: Department of Biological, Geological and Environmental Sciences, University of Bologna, Italy.
authors.forename: Luigia
authors.initials: L
authors.lastname: De Fazio
authors.affiliation: Department of Biological, Geological and Environmental Sciences, University of Bologna, Italy.
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Valerii
authors.affiliation: Department of Biological, Geological and Environmental Sciences, University of Bologna, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Cavazza
authors.affiliation: Institute for Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Brambilla
authors.affiliation: Hyperbaric Center of Ravenna, Via Augusto Torre 3, Ravenna, Italy.
authors.forename: Klarida
authors.initials: K
authors.lastname: Hoxha
authors.affiliation: Institute for Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: L'Abbate
authors.affiliation: Institute for Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.|Hyperbaric Center of Ravenna, Via Augusto Torre 3, Ravenna, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Longobardi
mesh_terms: D000388:Air; D000465:Algorithms; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D018925:Chemokines / Q000097:blood; D003664:Decompression / Q000379:methods*; D004242:Diving / Q000502:physiology*; D004452:Echocardiography; D004618:Embolism, Air / Q000000981:diagnostic imaging; D006371:Helium; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D007378:Interleukins / Q000097:blood; D009584:Nitrogen; D010100:Oxygen; D012623:Seawater; D013550:Swimming; D013997:Time Factors
chemical_list: D015415:Biomarkers; D018925:Chemokines; D018836:Inflammation Mediators; D007378:Interleukins; D006371:Helium; C045257:trimix; D009584:Nitrogen; D010100:Oxygen
keywords: Bubbles; Chemokines; Decompression tables; Echocardiography; Inflammation; Scuba diving