Khalil 2011.

Study characteristics
Methods	Randomised controlled trial Setting: security forces hospital, Riyadh, Saudi Arabia
Participants	Women with uncontrolled primary atonic PPH during caesarean section and not responding to standard treatment (standard treatment not described). PPH was not defined. Exclusions: < 28 weeks' gestation Traumatic bleeding or placenta praevia
Interventions	Intervention: Bakri balloon inserted intraoperatively through uterine incision, then secured with traction stitch (25 women). "Bakri balloon was fixed with nylon loop stitching through the hole of its proximal shaft, and the needle was then passed through the uterine cavity and the anterior abdominal wall. The thread was fixed to the skin to keep the balloon within the uterine cavity without any additional packing or the insertion of a balloon vaginally" p 198. Control: Bakri balloon intraoperatively through uterine incision, without traction stitch (25 women) Both groups of women received intravenous antibiotics for the first 48 hours and oxytocin infusion for the first 8 hours. It is not clear how much saline was used to inflate the balloons...the trial report states that, "the balloon was inflated until it conformed to the contour of the uterus in order to provide a symmetric tamponade effect" p 198
Outcomes	Displacement of Bakri balloon Bleeding after displacement of balloon Blood loss (estimated) Hysterectomy Other surgical intervention needed Bleeding after deflation of the balloon
Notes	The study was stopped after 50 cases because there was a high rate of Bakri balloon displacement in the control group. Trial authors' declarations of interest: "the authors have no conflicts of interest" p 199 Sources of trial funding: not reported Trial dates: 1 April 2004 and 30 April 2009 Ethical approval? "the hospital ethics committee approved the study" p198 Informed consent? yes, "informed consent was obtained from all participants" p 198 Contacted trial authors?: yes, email to Dr Khalil on 25 Aug 2018 requesting data on dichotomous blood loss outcomes. Data sent to ADW on 06 Sep 2018.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Computer‐based random sampling" p 198
Allocation concealment (selection bias)	Unclear risk	Methods of allocation concealment not mentioned
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding not mentioned. Assume blinding of personnel not possible due to difference in intervention techniques between groups
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete outcome data
Selective reporting (reporting bias)	Unclear risk	Protocol not available. Insufficient information to make an assessment of reporting bias
Other bias	Low risk	No other sources of bias were apparent