Tapping

Tapping is an operation frequently resorted to for the removal of fluid accumulations, particularly in the pleural and peritoneal cavities. It consists in introducing one end of a small tube into the cavity, with the least possible injury to the skin, and withdrawing so much of the fluid as is desired by siphon action, or by means of a vacuum. Various contrivances (aspirators) have been used to effect this without allowing air to enter—the commonest form that devised by Dr Potain. These instruments have done much for the certain diagnosis and safe treatment of fluid collections in various situations. Besides dropsical or inflammatory exudations in the pleura or peritoneum, similar collections in the pericardium can be thus dealt with; cysts and abscesses, when deep-seated and obscure, can be recognised with certainty and sometimes cured; and occasionally the fluid present in chronic hydrocephalus can be diminished with amelioration of symptoms. Collections of air or gas within the body may sometimes be removed in the same way with good results. See DROPSY, PLEURISY, &c.