AFP and encephalitis: Brainstem encephalitis combined with AFP, encephalitis combined with AFP and meningitis combined with AFP were risk factors for cardiopulmonary failure, and the univariate logistic regression analysis of the relationship between AFP (simple and mixed) and cardiopulmonary failure showed that AFP remained a risk factor for cardiopulmonary failure (odds ratio 10.9[6.0–19.8], P = 0.000).