[abstract] CHANGES OF PARAMETERS OF DISSEMINATED INTRAVASCULAR COAGULATION TEST IN DECOMPRESSED RABBITS.

Abstract

BACKGROUND: Decompression sickness (DCS) is caused by bubble formation which induces Intravascular coagulation abnormalities. Philp et al further suggested that DIC was similar to disseminated intravascular coagulation (DIC). This preliminary report is to study the changes of parameters of DIC such as platelet, prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and factor VI in decompressed rabbits. METHODS: Thirty-two male New Zealand rabbits, 2.5±0.5 (1.4 -4.0)kg in weight, were subjected to a simulated air-dive profile of 6 ATA for 45 min in a hyperbaric animal chamber. All the descent and ascent rates were at 1 ATA/min. Both before and after dive, 3.7 ml of venous blood were taken. 1 ml of blood were aixed in an EDT A tube and measured by a automated hematology analyzer (CELL-DYN, 1600) for platelet count. 2.7 ml of blood were mixed in a test tube with 0.3 ml of sodium citrate and measured by a automated coagulometer (ORGANON TEKNIKA, COAG-A-MATE XC) for PT, APTT, fribrinogen and factor VI. The bubble signals were detected over precordium with a Doppler ultrasonic bubble detector (TSI, Kodel D¥B 9008) after dive. After observation of clinical symptoms the rabbits were sacrified and the lungs were taken for pathology (classified by the Philp's pathology score). RESULTS: All subjects showed positive findings of bubble signal after dive. Among the seventeen had no signs of DCS' five developed paraplegia; and ten died. The pathological findings of lungs in 18 subjects demonstrated the evidences of capillary engorgement (score 2, n=I), venous fibrin clots (score 3, n=4),and platelet aggregates (score 4, n=13). The changes of parameters in DIC test after dive showed that there were decreases in the concentrations of platelets, fibrinogen, and factor VII and prolongation of PT and APTT as follows: Table: Changes of DIC parameters after decompression (n=32); Platelet (k/ul), Prothrombin time (INR), Fibrinogen (mg/dl) APTT (sec) FactorVII (%); pre-dive 559.5± 159.1 1.02±0.12 269. 9± 94.4 21.8±2.2 45.9±25.7; post-dive 445.4± 216.5 1.09±0.14 251.8± 104.9 22.6±2.3 39.5±27.1; paired t -test P < 0.01 P < 0.01 P :;; 0.05 P < 0.10 P > 0.10; INR - International Normalized Ratio. CONCLUSION: From our laboratory changes of blood and the pathological findings of lungs, we suggested that the bubble formation from decompression could induce a syndrome similar to that seen in DIC.