( ( ( The children ) ( with ( ( the ( lowest levels ) ) ( of ( ( ( ( carbon dioxide ) ( in ( their blood ) ) ) and ) ( ( the ( highest levels ) ) ( of ( urea nitrogen ) ) ) ) ) ) ) ) ( ( appeared ( to ( be ( at ( ( the ( greatest risk ) ) ( for ( brain swelling ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS children)) (PP (IN with) (NP (NP (DT the) (JJS lowest) (NNS levels)) (PP (IN of) (NP (NP (NP (NN carbon) (NN dioxide)) (PP (IN in) (NP (PRP$ their) (NN blood)))) (CC and) (NP (NP (DT the) (JJS highest) (NNS levels)) (PP (IN of) (NP (NN urea) (NN nitrogen))))))))) (VP (VBD appeared) (S (VP (TO to) (VP (VB be) (PP (IN at) (NP (NP (DT the) (JJS greatest) (NN risk)) (PP (IN for) (NP (NN brain) (VBG swelling))))))))) (. .)))
The children with the lowest levels of carbon dioxide in their blood and the highest levels of urea nitrogen appeared to be at the greatest risk for brain swelling.
(ROOT (S (NP (DT The) (NN brain)) (VP (VBP stem) (S (NP (NP (NN monitor)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-))) (NP (NP (DT the) (NN level)) (PP (IN of) (NP (NP (NN carbon) (NN dioxide)) (PP (IN in) (NP (DT the) (NN blood)))))))) (. .)))