[Relationship between the state of intravascular bubbles and microcirculation system].
To confirm the hypothesis that air bubbles were unable to block the blood vessels and that the state of the intravascular bubbles was determined by the function of the circulatory system, 35 guinea pigs were pressurized then were decompressed to normal pressure. Microscopic observation was made of the bulbar conjunctival, dorsum auricular and subcutaneous vessels in 33 surviving animals. Air bubbles of different amounts, sizes and shapes were found in the dorsum auricular and subcutaneous vein of all the amimals and in the bulbar conjunctival oriridal artery of 16 animals, and in some cases the vessels were even filled with bubbles. The bubbles ran in the same direction and at the same speed as the blood flow. They could run in a backward, to-and-fro or sluggish flow. The bubbles looked shapeless and tended to break and divided into branch flows where the vessel branches. The bubbles were motionless at the proximal end of the artery occluded due to spasm or when the blood was stagnated. Under the action of the blood pressure the bubbles could expand the vessel and push forward. The bubbles showed a tendency of flowing with ease with the function of the vessel recovered. The results suggest that bubbles of any size in the vessel could easily change their shape under the action of the blood flow and pressure, and pass through vessels of any diameter and circulate with the blood.  Only when a vessel was occluded due to spasm or the blood in a vessel was stagnated could the bubbles be motionless, but it was not that the bubbles blocked the vessel.
Yuan
J
J
Naval Medical Research Institute, Shanghai, China.
Pan
L
L
Wang
Q
Q
Ji
Z
Z
Gao
J
J
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D003664:Decompression; D003665:Decompression Sickness / Q000503:physiopathology; D004618:Embolism, Air / Q000503:physiopathology*; D006168:Guinea Pigs; D008833:Microcirculation / Q000503:physiopathology* / Q000648:ultrastructure*