Bloat is a painful, potentially life-threatening condition in dogs, and the stomach is the primary organ involved. Bloat is an emergency -- immediately take Rover to the veterinarian if you notice his abdomen distending.
If Rover has bloat, his stomach may distend with food, fluid or air. The cause may be slowed transit out of the stomach, a stomach mass or a consumed object blocking the stomach exit. The "Merck Veterinary Manual" states that, in gastric dilation and volvulus, the stomach twists, trapping material in the stomach. Rover’s distended stomach can put pressure on blood vessels, such as the vena cava, which lowers his blood pressure and can lead to shock. The distension can also place pressure on the diaphragm, preventing Rover from being able to breathe easily. The stomach tissues can necrose or die due to the stress on the tissue and decreased blood supply. With gastric volvulus, the spleen’s vessels can rupture, damaging the spleen, as well. Due to these complications, emergency surgery may be necessary to assess the health of the stomach and spleen.