Effects of simulated heliox diving on blood cells of the divers at different high altitudes

Abstract

Objective To investigate effects of simulated heliox diving on blood cells of the divers at different high altitudes.Methods In the dual-purpose hyperbaric and hypobaric chamber complex,4 divers conducted a series of simulated dives for a succession of 9 days at various altitudes and under different simulated environmental conditions:the 30 m dive at an altitude of 3000 m,the 30 m dive at an altitude of 4000 m,and the 30 m and 50 m dives at an altitude of 5200 m.Blood samples were taken respectively at the following time points:on the morning of the first day of the experiment before they entered the chamber on an empty stomach;on the morning of the third day of the experiment at an altitude of 3000 m also on an empty stomach; at 17:30 pm before supper on the fourth day of the experiment,when the divers were decompressed and returned to the surface at an altitude of 3000 m,upon completion of the 30 m-dive; at 17:30 pm before supper on the sixth day,when the divers returned to the surface at an altitude of 4000 m,upon completion of the 30 m-dive; on the morning of the seventh day on an empty stomach,the divers stayed overnight at an altitude of 5200 m; at 23:00 on the eighth day,when the divers were decompressed to an altitude of 5200 m,upon completion of the 50 m-dive; before lunch on the ninth day,when the divers came out of the chamber upon completion of the experiment.Blood components including WBC,WBC classification,RBC,hemoglobin,lymphocyte,granulocyte,hemoglobin,hematocrit,platelet and T lymphocyte subpopulation,were measured with flow cytometry.Results White blood cells detected at various time points both before and after the experiment tended to increase gradually,but without statistical significance (P ＞ 0.05).When the divers stayed at the height of 5200 m above sea level,the percentage of granulocyte was significantly higher [(6.21 ± 3.27) × 109/L] than those at the sea level [(3.22 ± 1.18) × 109/L] and at 3000 m above sea level [(3.43 ± 1.18) × 109/L] (P ＜ 0.01),while the percentage of lymphocyte decreased significantly (P ＜ 0.01) and corresponding changes in the amount of granulocyte and lymphocyte could be observed at the same time points (P ＜ 0.05).When the divers were decompressed to the altitude of 5200 m upon completion of the 50 m simulated dive at 5200 m above sea level,lymphocyte counts significantly increased [(2.28 ± 0.30) × 109/L],when compared with those at the plain [(2.02 ±0.15) × 109/L] and at 3000 m[(2.20 ±0.26) × 109/L] (P ＜ 0.05).No obvious changes could be noted in white cells at other time points.No statistical significance could be noticed in changes of red blood cell,hemoglobin,hematocrit,platelet and T lymphocyte subpopulation at various time points during the experiment,when compared with those at the plain and at 3000 m (P ＞ 0.05).Conclusions The simulated heliox diving at different high altitudes didnt seemed to have obvious effects on the blood routines of the divers. Key words: High altitude; Heliox diving; Blood cell; T lymphocyte