Table 1.

.

Time period	Overall (Jan 2012–May 2020) N = 241	Jan 2012–Dec 2014  N = 44	Jan 2015–Dec 2017  N = 82	Jan 2018–Jul 2019  N = 72	Aug 2019–May 2020  N = 43	p value
Procedure age (days)
Mean ± SD	38 ± 33.6	76 ± 53.7	35 ± 18.6	31 ± 21.4	19 ± 7.6	< 0.00001
Median (range)	28 (8–211)	60 (14–211)	28 (14–140)	27 (9–145)	18 (8–38)
Procedure weight (g)
Mean ± SD	1229 ± 528	1872 ± 546	1161 ± 419	1054 ± 420	992 ± 308	< 0.00001
Median (range)	1000 (500–3000)	1985 (745–3000)	1000 (640–2400)	900 (580–2600)	900 (500–1600)