Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: We investigated whether direct hemoperfusion with an immobilized polymyxin B column (DHP with PMX) could reduce the blood level of neutrophil elastase.', '20 sepsis patients were enrolled in the study. DHP with PMX was performed twice within a 24-hour period. Neutrophil elastase was measured 7 times.', 'Neutrophil elastase was 468 +/- 75.1 microg/l, while it was 1,531 +/- 201.7 microg/l immediately after the first session, declined to 351 +/- 73.9 microg/l before the second session of DHP with PMX, and increased again to 599.3 +/- 112.7 microg/l immediately after the second session, 328 +/- 73.7 microg/l at 24 h, 264 +/- 39.3 microg/l at 48 h, and 230 +/- 36.1 microg/l at 72 h after DHP with PMX. The levels from 48 h onwards were significantly lower compared with that before treatment.
Answer: DHP with PMX has an overall effect that reduces circulating neutrophil elastase levels.
Does hemoperfusion with an immobilized polymyxin B column reduce the blood level of neutrophil elastase?