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Figure 3 depicts the disposition of all articles included in the search and lists the reasons for exclusion. The search identified 1,428 nonduplicate articles, of which 1,362 were identified via literature search and 66 via hand-searching of the reference lists of articles. Of the 1,428 nonduplicate articles, 854 were excluded at the abstract review phase, and 574 moved on to the full-text review phase. Of the 574 that moved on to the full-text review phase, 58 were included in the review and 516 were excluded. Of the 58 articles included, 21 were included in Key Question 1, 9 in Key Question 2, 6 in Key Question 3, 49 in Key Question 4, and 0 in Key Question 5. Of the 574 articles excluded, 501 did not address study questions, 415 were not related to the use of nitrous oxide for the management of labor pain, 392 included an ineligible study size, 215 were not original research, and 3 were not published in English. The number of articles addressing Key Questions and those excluded exceed the total number of articles in each category because some articles fit multiple exclusion criteria or addressed more than one Key Question.

Figure 3Disposition of articles identified by the search strategy

KQ = Key Question

* The number of articles addressing Key Questions and those excluded exceed the total number of articles in each category because some articles fit multiple exclusion categories or addressed more than one Key Question.

From: Results

Cover of Nitrous Oxide for the Management of Labor Pain
Nitrous Oxide for the Management of Labor Pain [Internet].
Comparative Effectiveness Reviews, No. 67.
Likis FE, Andrews JC, Collins MR, et al.

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