by a stepforward logistic regression analysis as independently
worsening the prognosis. A series of variables frequently
quoted as predisposing to NP was determined to be either
present or absent in the same 120 cases of NP and in an equal
number of randomly selected control subjects. After adjusting
for confounding, factors significantly predisposing to NP
were tracheal intubation, depressed level of consciousness,
underlying chronic lung disease, thoracic or upper abdominal
surgery, prior episode of a large volume aspiration, and
age older than 70 years. Since some of the factors influencing
the risk or the prognosis of NP are amenable to medical
intervention, a percentage of NP might be prevented and its
prognosis can be improved.
procedure.