Scientists debate the medical significance of clinically silent bubbles in divers' bloodstreams.
The nitrogen that is dissolved in the bloodstream under the increased partial pressures experienced at depth come out of solution as bubbles during a too-rapid ascent. Until recently, there was no way to determine whether or not there were nitrogen bubbles in the bloodstream in the absence of clinical symptoms. But within the last several years, Doppler ultrasound machines have been used to prove the presence of clinically silent bubbles in the bloodstreams of divers after completing dives that were within no-decompression limits. The medical significance of these silent bubbles is a subject of debate. Others contend the bubbles are a warning of impending DCS, but little else.