NATURE AND INCIDENCE OF BUBBLES IN THE SPINAL-CORD OF DECOMPRESSED GOATS

The nature of so-called autochthonous bubbles was investigated. Their presence in compressed/decompressed goats was compared with that in an imals killed before decompression and in controls. Ten goats (group I) were subjected to compression/decompression in air. Clinical signs of spinal decompression sickness usually occurred. Within 35 min of surf acing, the animals were given a lethal dose of thiopentone sodium, i.v .. Spinal cords were fixed by immersion in 10% formol saline. Histolog ically autochthonous bubbles appeared to arise from rupture of over-di stended blood vessels. The incidence of grossly dilated empty vessels (GDEV) was recorded. Seven goats (group 2) were similarly compressed b ut killed before decompression. In five animals of group I there was a greater number of GDEV than in controls (group 3, seven animals) but in the other five animals the incidence was similar to the controls. T he incidence of GDEV in group 2 was greater than in the controls (P < 0.05). The percentage of sections of spinal cord in which the meninges also contained GDEV was assessed. In all except two animals in group I,the percentage was higher than in the controls, whereas in group 2 t he percentage was higher than in the controls. The experiments show th at autochthonous bubbles arise as an artifact and that intravascular b ubbles arise in situ.