Deaths At Sea - Standard Coding of Causes

Would anyone know of the codes used by the masters of ships after enactment of the (US) Passenger Act of 1882? Passenger manifests after that time contained a column to record the date and cause of death. The master of the vessel must have had some standard reference to be able to code the cause of death, but that reference seems to have disappeared. I am currently transcribing the August 1887 manifest of the SS Alaska for the Immigrant Ships Transcribers Guild (ISTG). During that voyage from Liverpool to New York, 78 of the 1029 passengers died. The cause of death codes on the manifest range from 0 to 23, but I have no key to interpret the numbers. I would appreciate any help.