Overview of the ETPOS study

Overview of the ETPOS study

  • Issue 67

The ETPOS study group
Jens Meier
jens.meier@akh.linz.at

3-jens

Some costly and laborious parts of modern medicine (e.g., cancer medicine) are rigorously regulated, and in these fields standard operating procedures force the physician to follow given clinical pathways. Surprisingly, for other fields of medicine variety of care and the diversity of clinical pathways are the norm. For example, perioperative transfusion habits throughout Europe seem to depend on the country, the state, the city, the hospital, the department, or even the specific physician. Nearly every physician has recognised these differences of transfusion habits between different institutions and settings. The first study systematically dealing with this variability has been published by an Austrian group investigating different transfusion habits [1]. This group could demonstrate that for total hip or total knee replacement the probability for transfusion essentially depends on the centre where the surgical procedure has been performed. Furthermore, there was reasonable suspicion, that the single measures of modern Patient Blood Management (PBM) programmes were fragmentarily implemented throughout Austria. Now, nearly ten years later this variability of the implementation of different PBM measures has been repeatedly demonstrated by an observational study performed by the NATA (Network for the Advancement of Patient Blood Management, Haemostasis and Thrombosis) [2]. In their conclusion the authors state that the implementation of PBM remains extremely variable across centres. The relative importance of factors explaining RBC transfusion differs across institutions include some being patient related whereas others are related to the healthcare process. However, this study could not determine why physicians decided to transfuse or why they avoided transfusions in specific situations.

In fact, quite recently, European data investigating the attitude of European physicians towards transfusion practice were lacking, and there were no clinical observational studies that thoroughly described transfusion practices throughout Europe, analysing differences in the reasons why physicians give packed red blood cells (PRBCs) and coagulation factors or not. Furthermore, only little had been known about the effect of different transfusion policies on outcome. As is the case in other areas of medicine, the degree of variability in clinical practice represents a potential quality improvement opportunity.

Therefore, the scientific subcommittee Transfusion and Haemostasis of the European Society of Anaesthesiology decided in 2012 to initiate a trial with the aim to describe differences in perioperative transfusion practices and correlation with patient outcome. This study has been called the European Transfusion Practice and Outcome Study, or in short ETPOS (ClinicalTrials.gov Identifier: NCT01604083) [3].

The ETPOS study is the first international multicentre randomised trial looking at the motivation of anaesthesiologists for intraoperative transfusions. Centres volunteered to participate in the study via the homepage of the European Society of Anaesthesiology (ESA).

All patients undergoing an elective, non-cardiac surgical procedure at each of the participating hospitals were screened for inclusion. Only patients that received at least one PRBC unit intraoperatively during the study period (April 1–December 31, 2013) were included in the analysis. Data acquisition time was three consecutive months for each centre. There were no further specific inclusion criteria. The only exclusion criteria were age The overall intraoperative transfusion rate was 1.8%; 59% of transfusions were at least partially initiated as a result of physiological transfusion triggers – mostly because of hypotension (55.4%) and/or tachycardia (30.7%). Haemoglobin-based transfusion triggers alone initiated only 8.5% of transfusions. The Hb concentration just before transfusion was 8.1 (1.7) g dL−1 and increased to 9.8 (1.8) g dL−1 after transfusion. The mean number of intraoperatively transfused PRBC units was 2.5 (2.7).

This result is quite surprising: although European Society of Anaesthesiology transfusion guidelines recommend a threshold for transfusion of 7–9 g dL−1, more than 50% of patients ended up with a haemoglobin concentration of more than 10 g/dL after the surgical procedure. Even more surprising are the reasons for transfusion: more than 30% of patients were transfused due to hypotension or tachycardia, whereas signs of tissue hypoxia only played a minor role. The physiological triggers mainly used (hypotension and tachycardia) might have a low discriminative power for tissue hypoperfusion and often occurred at Hb values that are considered safe for tissue oxygenation in most patients. These results suggest that there is still an urgent need for further educational efforts that focus on the number of PRBC units to be transfused in the clinical setting, although the situation has improved significantly in the last few years.

 

References

  1. Gombotz H, Rehak PH, Shander A, Hofmann A. Blood use in elective surgery: The Austrian benchmark study. Transfusion 2007;47(8):1468-80.
  2. Van der Linden P, Hardy JP. Implementation of patient blood management remains extremely variable in Europe and Canada: The NATA benchmark project. EJA 2016 [Epub ahead of print]
  3. Meier J, Filipescu D, Kozek-Langenecker S, Llau Pitarch J, Mallett S, Martus P, Matot I; ETPOS collaborators. Intraoperative transfusion practices in Europe. BJA 2016;116(2):255-61.