Table 4.

Adverse events.

Adverse events, n (%)	Underwater polypectomies n = 195	Gas insufflation polypectomies n = 186	p Value
Overall			0.369
Immediate bleeding	14 (7.2)	22 (11.8)
Delayed bleedinga	2 (1.0)	1 (0.5)
Immediate bleeding
Sessile and flat polyps,  overall, n (%)	11 (10.2) n = 108	12 (10.7) n = 112	0.898
6–9 mm	1 (3.7) n = 27	1 (2.9) n = 35	>0.999
10–19 mm	5 (7.9) n = 63	9 (15.5) n = 58	0.193
≥20 mm	5 (27.8) n = 18	2 (10.5) n = 19	0.232
Pedunculated polyps,  overall, n (%)	3 (3.4) n = 87	10 (13.5) n = 74	0.019
6–19 mm	1 (1.5) n = 65	7 (11.1) n = 63	0.031
≥20 mm	2 (9.1) n = 22	3 (27.3) n = 11	0.304
Management
Hemoclip use,  overall, n (%)	14 (7.2)	22 (11.8)	0.121
Sessile and flat polyps,  overall, n (%)	10 (9.3)	12 (10.7)	0.719
Pedunculated polyps, n (%)	4 (4.6)	10 (13.5)	0.045
6–19 mm	2 (3.1)	7 (11.1)	0.093
≥20 mm	2 (9.1)	3 (27.3)	0.304
Use of argon plasma  coagulation,b n (%)	4 (21.1)	1 (4.3)	0.158

Polyp morphology assignment: flat, 0-IIa and 0-IIb; sessile, 0-Is; pedunculated, 0-Ip.¹³ For categorical variables, p values were obtained using Chi Square test or Fisher’s exact test, as appropriate.

^aDelayed bleeding occurred in two underwater polypectomy resections (one flat and one pedunculated polyp, respectively, each with a diameter of 15 mm) and in one gas insufflation polypectomy resection (pedunculated polyp with a diameter of 10 mm).

^bAll sessile or flat polyps.