as an exploratory medical procedure or an autopsy 
(ROOT (PP (IN as) (NP (NP (DT an) (JJ exploratory) (JJ medical) (NN procedure)) (CC or) (NP (DT an) (NN autopsy)))))
(ROOT (PP (IN ) (NP (NP (DT ) (JJ ) (JJ ) (NN )) (CC ) (NP (DT ) (NN )))))