He thought the biggest barrier was how to change the culture in the ED so that staff would ask screening questions.
( He ( ( thought ( ( the ( biggest barrier ) ) ( was ( how ( to ( ( ( change ( the culture ) ) ( in ( the ED ) ) ) ( so ( that ( staff ( would ( ask ( screening questions ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD thought) (SBAR (S (NP (DT the) (JJS biggest) (NN barrier)) (VP (VBD was) (SBAR (WHADVP (WRB how)) (S (VP (TO to) (VP (VB change) (NP (DT the) (NN culture)) (PP (IN in) (NP (DT the) (NNP ED))) (SBAR (RB so) (IN that) (S (NP (NN staff)) (VP (MD would) (VP (VB ask) (NP (NN screening) (NNS questions)))))))))))))) (. .)))
The biggest barrier was thought to be how to maintain the culture
( ( The ( biggest barrier ) ) ( was ( thought ( to ( be ( how ( to ( maintain ( the culture ) ) ) ) ) ) ) ) )
(ROOT (S (NP (DT The) (JJS biggest) (NN barrier)) (VP (VBD was) (VP (VBN thought) (S (VP (TO to) (VP (VB be) (SBAR (WHADVP (WRB how)) (S (VP (TO to) (VP (VB maintain) (NP (DT the) (NN culture)))))))))))))