Preparation of the Skin For Lumbar Puncture

To the Editor:—  We would like to call attention to "Skin Preparation for Lumbar Puncture: Ether or Soap?" (208:1196, 1969). Dr. Harvey Bernard, MD, of the Albany Medical College replied to the question concerning the use of hexachlorophene (Septisol) followed by benzalkonium chloride for skin preparation before lumbar puncture. We would like to submit the following additional information concerning the skin cleansing procedure.Benzalkonium (Zephiran) chloride, along with benzathonium ( Phemerol) chloride, and cetylpyridium ( Ceepryn) chloride are quanternary ammonium cationic surface-acting agents and germicides. When these germicides come in contact with anionic soaps, as are found in hexachlorophene ( Septisol and Phisohex), the large organic ions of opposite charges are attracted to one another, and decrease or destroy the bacteriostatic activity of the cationic surface-acting germicides.^1,2When surfaces have been washed with soap they must be thoroughly rinsed with water to remove any residual soap before applying a quanternary ammonium