Table 1.

Details of the studies

Ref.	Study type	Country	Time	No. of patients	Group	n	Age (mean/median years)	Gender (% male)	Population (inclusion criteria)
Koch et al[25]	Retrospective	United States	1995–2002	62	PI	42	49	74	Bleeding varices
					No PI	20	48	65	No radiographic or clinical respiratory issues
Rehman et al[24]	Retrospective	United States	2002–2006	98	PI	49	62b	61	Cirrhosis
					No PI	49	68b	82	Hematemesis Shock
a Perisetti et al[26]	Retrospective	United States	2000–2013	138	PI	69	61b	NA	Endoscopy with intubation
					No PI	69	66b	NA	Matched controls
a Tang et al[27]	Retrospective	United States	2008–2013	69	PI	43	53	69.8	Endoscopy in suspected variceal bleeding
					No PI	26	55	61.5

^aAbstract;

^bMedian.

PI: Prophylactic intubation; NA: Data not available.