( It ( ( is ( important ( to ( remember ( to ( ( ( avoid ( positive ( pressure ventilation ) ) ) ( during ( intense ( truncal rigidity ) ) ) ) ( because ( ( ( further increases ) ( in ( intrathoracic ( pressure decrease ) ) ) ) ( ( ( venous return ) and ) ( thereby ( may ( reduce ( ( ( cardiac output ) and ) ( blood pressure ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (ADJP (JJ important) (S (VP (TO to) (VP (VB remember) (S (VP (TO to) (VP (VB avoid) (NP (JJ positive) (NN pressure) (NN ventilation)) (PP (IN during) (NP (JJ intense) (JJ truncal) (NN rigidity))) (SBAR (IN because) (S (NP (NP (JJ further) (NNS increases)) (PP (IN in) (NP (JJ intrathoracic) (NN pressure) (NN decrease)))) (VP (VP (VBZ venous) (NP (NN return))) (CC and) (VP (ADVP (RB thereby)) (MD may) (VP (VB reduce) (NP (NP (JJ cardiac) (NN output)) (CC and) (NP (NN blood) (NN pressure)))))))))))))))) (. .)))
It is important to remember to avoid positive pressure ventilation during intense truncal rigidity because further increases in intrathoracic pressure decrease venous return and thereby may reduce cardiac output and blood pressure.
(ROOT (S (S (VP (VBG Reducing) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS molecules)) (PP (IN in) (NP (DT a) (JJ rigid) (NN container)))))))) (VP (VBZ causes) (NP (NN pressure)) (S (VP (TO to) (VP (VB decrease))))) (. .)))