Search Results
Among the 3275 records identified in the initial literature search, 2336 were assessed for their title and abstract after the removal of duplicates (Figure A). The full text of 106 articles was assessed, and six articles were eligible for inclusion in this systematic review, which included 1074 preterm infants (four RCTs14-17, one follow-up study of one RCT18, and one cohort study19). The largest RCT was conducted in Germany, and all other studies were conducted in the USA. The included studies varied in the median gestational age (24.7–27.3 weeks), duration of permissive hypercapnia (24 hr to 14 days), and target CO2 range (45–55 to 55–65 mmHg for the permissive hypercapnia group; 35–45 to 40–50 mmHg for the normocapnia group) as shown in Table 1. All studies used invasive mechanical ventilation, mainly intermittent positive pressure ventilation. The high-frequency oscillation mode was used only when necessary and was reported in two RCTs (Mariani 199914 and Thome 2015)17.