ICU patients undergoing PDT frequently have mild coagulation disorders which may increase their risk of bleeding during or after invasive procedures. In this study we compared bleeding in patients after correction of mild coagulation disorders to those without prior correction and found no differences. Notably, clinically significant bleeding was not present in either of the two study groups.
This trial has some important limitations. Firstly, this was an open-label study. Hypothetically, physicians who disbelieved that correction of mild coagulation disorders would benefit patients undergoing PDT may have tried to perform PDT in such a way that blood loss was kept to a minimum in the “no correction” group, or vice versa may have acted imprudently in the “correction” group. Secondly, the intended inclusion of 152 patients turned out to be unrealistic and the study was terminated prematurely. During conduct of the trial there was growing resistance of the ICU-physicians to infuse blood products, including platelet concentrates and plasma, because blood loss with PDT was found to be minimal. Given the early termination of this trial, the results should be interpreted with care. In addition, since the definition and hence, reported incidences of blood loss differ between studies, the number of patients needed for inclusion would have changed when different expected incidences were used for the power calculation. With hindsight, we might have overestimated the chance of bleeding and the effect size of blood products. However, we feel that the amount of bleeding we powered for was clinically relevant. Also, since there were several inclusion and treatment arms, the expected blood loss may differ between groups and even more patients may be needed to provide sufficient power to exclude a type II error definitely. Finally, although we report on possible aetiologies of the coagulation disorders, we did not report on feeding. Vitamin K shortage could have been an underestimated cause of mild coagulation disorders.
Inclusion was restricted to patients with mild coagulation disorders and/or active treatment with acetylsalicylic acid. Severe coagulation disorders were judged as an absolute contraindication to PDT unless haemostasis was carefully corrected18
. Patients treated with clopidogrel were also excluded because our national guideline on percutaneous tracheostomy advises that combinations of platelet aggregation inhibitors are best avoided, and many patients use clopidogrel in addition to acetylsalicylic acid. This may have resulted in a far lower rate of bleeding than assumed beforehand, and additional studies are needed to evaluate the safety of PDT in the case of combination treatment. It is worth noting that the PDT was performed by physicians with extensive experience with the technique and only the Blue Rhino technique was used although earlier studies did not show higher bleeding with one specific percutaneous technique6
It should be noted that this study was not designed according to current transfusion guidelines in which prophylactic transfusion of FFP is discouraged in ICU patients with mild coagulation disorders19–22
. However, in a recent survey on peri-operative management of PDT in the Netherlands, we found that it is common practice to correct for mild prolongation of PT before the procedure17
. Indeed, prophylactic transfusion of FFP before an invasive procedure in non-bleeding patients may often be given, even though the benefits with regards to preventing bleeding may be low19,20
. One could argue that the dose of FFP used in this study was too low, as transfusion of one unit of FFP hardly influenced the PT. International guidelines advise that in the case of major bleeding normal coagulation requires a correction of coagulation factors to 30% of normal. This requires at least four units of FFP when the circulating volume is 6 L. In addition, transfusion guidelines suggest that platelet transfusion may be indicated only when the platelet count is below 50×109
. However, prophylactic infusion with these amounts of plasma and platelets was in accordance with our hospital blood bank policy. Also, many ICU patients may suffer from thrombocytopathy (apart from thrombocytopenia), which could decrease the threshold for transfusion.
Transfusion of blood products bears the risk of transfusion-related morbidity, such as infectious diseases and transfusion-associated acute lung injury (TRALI)23,24
. In light of these insights one can speculate whether a transfusion policy such as that used in our ICU is even ethical. Unnecessary transfusion of FFP and platelets may occur too often. Education regarding the indications for transfusion and improved identification of active bleeding may reduce transfusion rates and costs20
. This study supports the policy of restrictive use of blood products by showing that transfusion of blood products before PDT in the case of mild coagulation disorders is not indicated and is an unnecessary expense.
Our results are in line with those of a large, prospective, observational study that evaluated risk factors associated with bleeding during and after PDT25
. That study showed no correlation between acute bleeding and coagulation disorders. In contrast to our results though, a correlation was found between chronic bleeding and coagulation disorders. Notably, the risk of bleeding was mostly present in patients with more severe bleeding disorders than those in the patients included in our study. In a recently published retrospective study a very low bleeding risk (1%) was found in patients with various coagulation disorders and it was concluded that, with strict adherence to a transfusion protocol and an experienced surgical team, PDT can be safely performed in these patients26
. However, patients with mild coagulation disorders were also transfused, which was probably unnecessary. We suggest that a standardised transfusion protocol be applied only to patients with more severe coagulation disorders.
Although one patient on active treatment with acetylsalicylic acid needed subcutaneous sutures to stop bleeding (which, it should be noted, was not clinically significant according the study definitions), we did not find a higher risk of bleeding in other patients using acetylsalicylic acid, even in those with an additional prolonged PT. The attitude towards withholding acetylsalicylic acid peri-operatively has been changing over the years. Most guidelines advise the continuation of acetylsalicylic acid for non-cardiac surgery, except in patients with a low risk of thrombosis when bleeding may occur in closed spaces, or when excessive blood loss is expected27,28
. The same recommendations are made for patients taking clopidogrel or dual anti-platelet therapy.
The continuously rising costs of blood donation and transfusion in the current economic environment stress the need for studies that challenge our current practices. We should aim to abolish superfluous infusion of blood products especially in critically ill patients.