Plasma transfusions prior to insertion of central lines for people with abnormal coagulation

Review question
We evaluated the evidence about whether people with abnormal coagulation (poor blood clotting) require a plasma transfusion prior to insertion of a central line (central venous catheter (CVC)), and if so, what is the degree of abnormal coagulation at which a plasma transfusion is required.

Background
People with abnormal coagulation often require the insertion of central lines. Central lines are catheters whose tip usually lies in one of two main veins returning blood to the heart. They have a number of uses including: intensive monitoring and treatment of critically-ill patients; giving nutrition into a vein (when the patient cannot eat); giving chemotherapy or other irritant drugs with fewer complications; and when patients require long-term repeated treatments in to a vein. Current practice in many countries is to give plasma transfusions to prevent serious bleeding due to the procedure if blood tests to assess clotting are abnormal. The risk of bleeding after a central line insertion appears to be low if the clinician uses ultrasound to guide insertion of the line. Correction of clotting abnormalities with fresh frozen plasma (FFP) is not without risks of its own, and it is unclear whether this practice is beneficial or harmful. People may be exposed to the risks of a plasma transfusion without any obvious clinical benefit.

Study characteristics
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.

Key results
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.

Quality of the evidence
The quality of the evidence is very low because this review includes only one small study.

Authors' conclusions

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.

Authors' conclusions: 

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).

Read the full abstract...
Background: 

The insertion of central venous catheters (CVCs) may be associated with peri- and post-procedural bleeding. People who require a central line often have disorders of coagulation as a result of their underlying illness, co-morbidities or the effects of treatment. Clinical practice in some institutions is to mitigate the risk of bleeding in these patients by prophylactically transfusing fresh frozen plasma (FFP) in order to correct clotting factor deficiencies prior to central line insertion. However, FFP transfusion is not without risk, and it remains unclear whether this intervention is associated with reduced rates of bleeding or other clinically-meaningful outcomes.

Objectives: 

To assess the effect of different prophylactic plasma transfusion regimens prior to central line insertion in people with abnormal coagulation.

Search strategy: 

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 3), PubMed (e-publications only), Ovid MEDLINE (from 1946), Ovid Embase (from 1974), the Transfusion Evidence Library (from 1950) and ongoing trial databases to 1 March 2016.

Selection criteria: 

We included RCTs involving transfusions of plasma to prevent bleeding in people of any age with abnormal coagulation requiring insertion of a central venous catheter, published in English.

Data collection and analysis: 

We used standard methodological procedures expected by Cochrane.

Main results: 

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.

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