Benefits and risks of liberal and restrictive transfusion regimens are under on-going controversial discussion. This systematic review aimed at assessing both regimens in terms of pre-defined outcomes with a special focus on patients undergoing major orthopedic surgery.

The researchers performed a literature search for mortality, morbidity and related outcomes following peri-operative blood transfusion in patients with major orthopedic surgery in electronic databases.

Combined outcome measure estimates were calculated within the scope of meta-analyses including randomized clinical trials comparing restrictive versus liberal blood transfusion regimens (e.g. MH risk ratio, Peto odds ratio).

A total of 880 publications were identified 15 of which were finally included (8 randomized clinical trials (RCTs) with 3,693 patients and 6 observational studies with 4,244,112 patients).

Regarding RCTs, no significant differences were detected between the transfusion regimes for all primary outcomes (30-day mortality, thromboembolic events, stroke/transitory ischemic attack, myocardial infarction, wound infection and pneumonia) and a secondary outcome (length of hospital stay), whereas there was a significantly reduced risk of receiving at least one red blood concentrate under a restrictive regimen.

Currently available data from RCTs do not support stricter guidelines. Publications aiming at the safety of patients under a strict patient blood management regimen are often based on retrospective data.

Blood management tools

Furthermore, low-risk patients are often included for which patient blood management does not apply, resulting in a significant selection bias. Moreover, the lack of randomization and of adjustment for risk factors is a significant source of confounding.

Patient blood management tools based on restrictive transfusion policies enable recording of treatment patterns as well as detection of misuse and may also sensitize physicians for this topic.

However, it should not be over-interpreted as a gold standard for risk minimization. Under this aspect, any transfusion policy should allow for individual solutions in patients with specific risks.

The results of this systematic review do not suggest an increased risk associated with either a restrictive or a liberal transfusion regimen in patients undergoing major orthopedic surgery.

Based on data originating from 8 RCTs, the results of this systematic review do not suggest an increased risk associated with either a restrictive or a more liberal transfusion regimen in patients undergoing major orthopedic surgery.

In this context, it is important to realize that our findings cannot easily be transferred to lower thresholds. Indeed, they apply only to the thresholds used in the clinical trials that were included in our meta-analyses.

For patients with cardiovascular risk factors, a more liberal transfusion regimen might be advisable, whereas patients with the history of stroke/TIA might benefit from a restrictive transfusion regimen. The German transfusion guidelines to reflect the current scientific knowledge. No further or more restrictive recommendations are currently warranted.