Mahul 1992.

Methods	Single‐blind randomised controlled trial
Participants	Baseline characteristics Number randomised: 158 participants Number analysed: 145 participants Overall Age (years; mean (SD)): 57.9 (18.5) Number of participants (n): 145 (antacids n = 72, sucralfate n = 73) Gender (male/female; n): 105/40 Inclusion criteria Admitted to ICU Intubation for more than 3 days (probably) Exclusion criteria No intubation (n = 79) Tracheostomy (n = 9) Intubated < 3 days (n = 163) lntubated > 3 days (n = 19) Vital risk for new intubation (n = 15) Intubated before ICU (n = 1) Gastric bleeding (n = 1) Oesogastrectomy (n = 2) Baseline imbalances: 48 participants had 'primitive pneumonia' on admission, 14 had tracheobronchitis, and bacterial colonisation was noted in 36 participants, respectively (not clear to which intervention these participants belonged)
Interventions	Antacids Dose (total/d): 80 mL Duration of treatment (days): ‐ Route: NG tube Intervention: aluminium hydroxide prescribed in 20 mL/6 h via NG tube Concomitant medications: enteral feeding in 13 participants. Gastric pH was assessed every 6 hours directly before administration of the assigned drug. When continuous enteral nutrition was performed, stress ulcer prophylaxis was maintained but gastric pH measures were discontinued. No selective decontamination of the digestive tract was performed Sucralfate Dose (total/d): 6 g Duration of treatment (days): ‐ Route: NG tube Intervention: sucralfate:1 g/6 h via NG tube Concomitant medications: enteral feeding in 14 participants. Gastric pH was assessed every 6 hours directly before administration of the assigned drug. When continuous enteral nutrition was performed, stress ulcer prophylaxis was maintained but gastric pH measures were discontinued. No selective decontamination of the digestive tract was performed Adherence to regimen: Quote: "A single blind randomisation was performed within 12 hours of admission according to a simultaneous and independent dual randomisation. The first randomisation involved mechanical SSD versus no‐SSD. The second randomisation involved ulcer prophylaxis with aluminium hydroxide versus sucralfate. At the end, 4 random classes were defined" "158 of them were randomly selected on the probability of intubation for more than 3 days, 13 were then excluded because of death (n = 5) or extubation (n = 8) before day 3" Duration of trial: 14 months Duration of follow‐up: not clearly mentioned in the study report
Outcomes	Outcomes sought in review and reported in trial Incidence of nosocomial pneumonia: A new and persistent infiltrate on the chest X‐ray occurring after 2 days of intubation was considered as nosocomial pneumonia, with an aerobic micro‐organism on BAL ≥ 10.5 cfu/mL. In the first 2 days, it was considered to be an early pneumonitis and was included with primary pneumonia Incidence of GI bleeding All‐cause mortality in ICU Outcomes sought but not reported in trial report All‐cause mortality in hospital Duration of ICU stay Duration of intubation Number of participants requiring blood transfusions Number of units of blood transfused Adverse events of interventions Outcomes reported in report but not used in review Prevention of aspiration by mechanical drainage of subglottic secretions (SSD) above the tracheal cuff Prevention of gastric  colonization by prophylaxis of ulcer bleeding Association between SSD and gastric colonization rates and gastric pH values Association between stress ulcer prophylaxis and gastric colonization rates and gastric pH values
Notes	Setting: Hospital Nord, CHRU St. Etienne, France Source of funding: ‐ Conflicts of interest: ‐ Ethics approval: ‐ 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	Unclear risk	Quote: "A single blind randomisation was performed within 12 hours of admission according to a simultaneous and independent dual randomisation" Comment: not clear who were blinded. Therefore, unclear on the likelihood of performance bias
Blinding (detection bias) Clinically important upper GI bleeding	Unclear risk	Quote: "A single blind randomisation was performed within 12 hours of admission according to a simultaneous and independent dual randomisation" Comment: unclear on blinding of outcome assessors. The definition for detecting GI bleeding is not clearly mentioned in the study report
Blinding (detection bias) Nosocomial pneumonia	Low risk	Comment: unclear on blinding of outcome assessors. Nosocomial pneumonia was detected as per the definition in the study protocol
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	Comment: Of the 158 randomised participants, only 145 were part of the final analysis. There were 13 dropouts for the reasons mentioned above. The group to which they were randomised is not clearly mentioned in the study report, and an intention‐to‐treat analysis was not done.However, the dropouts accounted for less than 10% of randomised participants and appear to be equally distributed (given the double randomisation design of the study). Therefore, the likelihood of attrition bias is low
Selective reporting (reporting bias)	Low risk	Comment: All intended outcomes were analysed and reported
Other bias	High risk	Comment: source of funding and baseline imbalances of antacid and sucralfate groups unclear