Tryba 1987.

Methods	Single‐blind randomised controlled trial
Participants	Baseline characteristics Number randomised: 100 participants Number analysed: 100 (for all outcomes except for pneumonia, reasons mentioned below) Antacid Age (years; median (SD)): 43.7 (20.1) Number of participants (n): 50 Gender (male/female; n): 28/22 Sucralfate Age (years; median (SD)): 44.9 (20.6) Number of participants (n): 50 Gender (male/female; n): 31/19 Inclusion criteria Total risk score of at least 10 as devised by Tybra et.al Undergone mechanical ventilation for at least 1 day Has not undergone surgery of the upper GI tract Exclusion criteria Admitted to the unit because of acute GI haemorrhage Gastric or duodenal ulcer in the preceding 12 months Baseline imbalances: Quote: "Both the groups were comparable on basic clinical or laboratory parameters" Comment: Both groups were comparable with respect to the distribution of demographic characteristics and risk factors
Interventions	Antacids Dose (total/d): 120 mL Duration of treatment (days, mean (SD)): 5.6 (4.0) Route: gastric tube Intervention:antacid containing aluminium hydroxide, magnesium hydroxide, or calcium carbonate with a high neutralizing capacity given as 10 mL every 2 hours Concomitant medications: Routine potassium phosphate was given to all participants. Details on antibiotic therapy are not clearly mentioned in the study report. Treatment was started within the first 12 hours of admission of participants to the unit Sucralfate Dose (total/d): 25 mL Duration of treatment (days, mean (SD)): 6.2 (4.6) Route: gastric tube Intervention: 5 mL sucralfate suspension was given every 4 hours through the stomach tube, which was then rinsed with 10 to 15 mL of water Concomitant medications: Routine potassium phosphate was given to all participants. Details on antibiotic therapy are not clearly mentioned in the study report. Treatment was started within the first 12 hours of admission of participants to the unit Adherence to regimen: Antacid therapy was discontinued in 3 participants (vomiting after extubation (n = 2) and alkalosis on the second day (n = 1)) Duration of trial: July 1984 to November 1986 Duration of follow‐up: ‐
Outcomes	Outcomes sought in review and reported in trial Primary outcomes Significant upper GI bleeding: Evidence of occult bleed in gastric juice aspirate was disregarded, therefore, macroscopically visible bleeding was taken into consideration (haematemesis, bloody aspirate, or melena) as the criteria for acute GI haemorrhage Diagnosis of pneumonia: radiographic evidence of pulmonary changes, temperature above 38.5°C, leucocytosis, bacteria in the tracheal smear, and suggestive changes in arterial blood gases. A diagnosis of pneumonia was established; only radiologic changes were present along with 3 further criteria. Only participants who showed no pathologic pulmonary changes were included in the analysis (participants showing signs of pneumonia on admission to ICU or those who had undergone thoracic trauma were excluded from analysis) Secondary outcomes Adverse drug reactions Duration of ventilation All‐cause mortality in ICU Participants requiring blood transfusions Duration of intubation Outcomes sought but not reported in trial All‐cause mortality in hospital Duration of ICU stay Outcomes reported but not used in review Gastric pH values
Notes	Setting: Department of Anaesthesiology, Hannover School of Medicine, Hannover, Federal Republic of Germany Source of funding: Quote: “This study was supported by a grant from E. Merck” Ethics approval: Quote: "...with the approval of the local ethical committee and in accordance with the guidelines of the German Drug Law" Informed consent: ‐ Clinical trials registration: ‐ Sample size calculation: ‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: not clearly mentioned in the study report
Allocation concealment (selection bias)	Unclear risk	Comment: not clearly mentioned in the study report
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: This was not a placebo‐controlled trial, and the different modes of administering study interventions would not have made it possible to blind study personnel and participants. Therefore, high risk of performance bias
Blinding (detection bias) Clinically important upper GI bleeding	Low risk	Comment: unclear whether outcome assessors were blinded. GI bleeding was detected as per the definition in the study protocol. Therefore, the likelihood of detection bias is low
Blinding (detection bias) Nosocomial pneumonia	Low risk	Quote: "The diagnosis of pneumonia was done by a physician who was unaware of the object of the study” Comment: There was clear definition for diagnosing pneumonia, and the outcome assessor was blinded to the interventions. Therefore, the likelihood of detection bias is low
Blinding of outcome assessment (detection bias) Adverse reactions of interventions	Low risk	Comment: unclear on blinding of outcome assessors. However, outcomes of interest were objective in nature, so the likelihood of detection bias is low
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: “For analysis of pulmonary infections, 39 participants were withdrawn from the study because of thoracic trauma or pneumonia at the time of admission to ICU (18 from antacid arm and 21 from sucralfate arm)” For all other outcomes, all 100  randomised participants were part of the analysis Comment: Excluding these participants is justified as it could not have led to the true estimate of the outcome (incidence of nosocomial pneumonia) due to the intervention
Selective reporting (reporting bias)	Low risk	Comment: All intended outcomes were analysed and reported
Other bias	Low risk	Comment: Study was supported by a grant from E. Merck. The role of the sponsor in the conduct and reporting of the trial is unclear. No other form of bias detected