Abstract: We identified four trials eligible for inclusion, of which three are ongoing. We did not exclude any studies because they were not published in English. The included study randomised 81 adults in intensive care whose INR (International Normalised Ratio) was greater than or equal to 1.5 to no FFP or to a single dose of 12 mL/kg FFP prior to undergoing central venous catheterisation (58 participants) or other invasive procedure (23 participants). It is the subgroup of 58 adults undergoing CVC insertion that were included in this review, the study authors provided unpublished data for this review's outcomes. The quality of the evidence was low or very low across different outcomes according to the GRADE methodology. The included study was at high risk of bias due to lack of blinding of participants and personnel and imbalance in the number of participants who had liver disease between study arms. There was insufficient evidence to determine a difference in major procedure-related bleeding within 24 hours (one RCT; 58 participants; no events in either study arm, very low-quality evidence). We are very uncertain whether FFP reduces minor procedure-related bleeding within 24 hours of the study (one RCT; 58 participants, RR 0.67, 95% CI 0.12 to 3.70, very low-quality evidence). No studies were found that looked at: all-cause mortality; the proportion of participants receiving plasma or red cell transfusions; serious adverse reactions (transfusion or line-related complications); number of days in hospital; change in INR; or quality of life. The three ongoing studies are still recruiting participants (expected recruitment: up to 355 participants in total). and are due to be completed by February 2018. There is only very limited evidence from one RCT to inform the decision whether or not to administer prophylactic plasma prior to central venous catheterisation for people with abnormal coagulation. It is not possible from the current RCT evidence to recommend whether or not prophylactic plasma transfusion is beneficial or harmful in this situation. The three ongoing RCTs will not be able to answer this review’s questions, because they are small studies and do not address all of the comparisons included in this review (355 participants in total). To detect an increase in the proportion of participants who had major bleeding from 1 in 100 to 2 in 100 would require a study containing at least 4634 participants (80% power, 5% significance).

Plain-language summary: The evidence is current to March 2016. In this review we identified four randomised controlled trials, three trials are still recruiting participants and are due to complete recruitment by February 2018. The completed trial (58 participants) compared plasma transfusion to no plasma transfusion prior to central line insertion. There was not enough evidence to determine whether plasma transfusions affected minor or major procedure-related bleeding. The included study did not report the number of people dying due to any cause, the number of people receiving red cell or plasma transfusions, the occurrence of transfusion or line-related complications, length of time in hospital, correction of clotting abnormalities, or quality of life. The quality of the evidence is very low because this review includes only one small study. The ongoing studies (expected to recruit 355 participants in total) will be unable to provide sufficient data for this review’s primary outcomes because major bleeding and mortality are uncommon. We would need to design a study with at least 4634 participants to be able to detect an increase in the number of people who had major bleeding from 1 in 100 to 2 in 100. It is not possible from the current randomised controlled trial evidence to recommend whether or not prophylactic plasma transfusion is beneficial or harmful in this situation.