Table 1.

Comparison of Water Assisted Method and Air Insufflation Method Regarding Pain Reduction

Study	Number	Sedation	Pain score reduction (WI-AI)	p-value
WI method
Brocchi et al. (2008) [18]	170	None	-1.7	0.001
Park et al. (2010) [19]	39	None	-0.2	0.894
Leung et al. (2010) [20]	114	Minimal	-1.2	0.001
Hsieh et al. (2011) [21]	90	Minimal	-0.9	0.021
Hsieh et al. (2011) [22]	51	Minimal	-1.4	0.004
Radaelli et al. (2010) [23]	114	On-demand	-1.1	0.001
Pohl et al. (2011) [16]	58	On-demand	-1.9	<0.05
WE method
Leung et al. (2009) [24]	28	Minimal	-2.8	0.0002
Leung et al. (2010) [25]	40	None	-3	0.002
Leung et al. (2011) [26]	50	On-demand	-2.6	0.012
Cadoni et al. (2015) [17]	209	On-demand	-2.9	<0.0005

WI, water immersion; AI, air insufflation; WE, water exchange.