Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Wound infection
Systematic review	3577 people who had undergone abdominal surgery 15 RCTs in this analysis	Wound infections 77/1287 (6%) with selective use 58/1283 (5%) with routine use	RR for routine use v selective use 0.76 95% CI 0.56 to 1.04 P = 0.08		Not significant
Nausea and vomiting
RCT	200 people having hepatic resection	Nausea 31/100 (31%) with removal of the nasogastric tube at the end of the operation (selective use) 20/100 (20%) with routine use	Reported as not significant P value not reported		Not significant
RCT	40 people having surgery of the infrarenal aorta	Nausea 3/20 (15%) with removal of the nasogastric tube at the time of tracheal extubation (selective use) 3/20 (15%) with routine use	Reported as not significant P value not reported		Not significant
RCT	200 people having hepatic resection	Emesis on removal of nasogastric tube 10/100 (10%) with removal of the nasogastric tube at the end of the operation (selective use) 2/100 (2%) with routine use	P = 0.011	Effect size not calculated	routine use
RCT	40 people having surgery of the infrarenal aorta	Vomiting 2/20 (10%) with removal of the nasogastric tube at the time of tracheal extubation (selective use) 3/20 (15%) with routine use	Reported as not significant P value not reported		Not significant
Tube replacement
RCT	40 people having surgery of the infrarenal aorta	Tube replacement 1/20 (5%) with removal of the nasogastric tube at the time of tracheal extubation (selective use) 2/20 (10%) with routine use	Reported as not significant P value not reported		Not significant
Complications (other)
RCT	316 people having surgery for colorectal carcinoma	Abdominal distension 3/161 (3%) with removal of the nasogastric tube 12–24 hours after surgery (selective use) 1/155 (1%) with routine use	P = 0.623		Not significant
Systematic review	480 people who had undergone abdominal surgery Data from 1 RCT	Ventral hernias 15/229 (7%) with selective use 8/251 (3%) with routine use	RR for routine use v non-routine use 0.47 95% CI 0.20 to 1.13 P = 0.09		Not significant
RCT	200 people having hepatic resection	Severe discomfort with removal of the nasogastric tube at the end of the operation (selective use) with routine use