Clinical Trial Summary
Delirium is one of the most common complications after cardiac surgery and occurs with an
incidence of 3 - 70%.
Both predisposing factors (age, diabetes, severity of cardiac disease, atrial fibrillation)
and precipitating factors (type of surgery, duration of cardiopulmonary bypass (CPB) and
surgery, ventilator time in ICU, highest temperature in intensive care (ICU)) are difficult
to influence. Post-operative delirium is a devastating complication, leading to longer ICU
and hospital stay, increased incidence of discharge to nursing facility and poorer long-term
cognitive outcome.
Despite the impact this complication has on individuals, their families and healthcare
resources, little is known about the causes and potential preventative measures.
It is thought that systemic inflammation compromising the integrity of the blood brain
barrier is an important contributing factor. Recent data suggests that antifibrinolytics like
tranexamic acid (TXA) might be able to lessen the inflammation of the nervous system caused
by surgery and CPB through the inhibition of plasmin production, thereby stabilising the
blood brain barrier. Worldwide, the use of TXA has become standard of care in cardiac surgery
and other types of surgery with a high risk of bleeding. It has been shown to reduce bleeding
by 25% and significantly reduce the rate of transfusion in cardiac and noncardiac surgery.
At Royal Papworth hospital it is routine practice to administer 2g of TXA before commencing
CPB irrespective of patients' body weight. We are hypothesising that there is a weight-based
effect of TXA on neurological outcomes after cardiac surgery, showing a signal that a higher
dose per kg bodyweight will lead to less delirium measured with the Richmond
Agitation-Sedation Score (RASS). We intend to analyse 4 years' worth of patient data (05/2018
- 08/2022); the necessary information is routinely collected on using the hospital
anaesthetic and ICU record.
There will be no patient contact at any point of this retrospective analysis. The data
collected will have been routinely collected on the hospital's electronic systems as part of
routine clinical care and data collection.
This is a very new field of interest in cardiac anaesthesia / surgery. No clinical data is
currently available apart from recent preliminary data suggesting that Tranexamic Acid (TXA)
improves the inflammatory reaction the nervous system has to surgery and cardiopulmonary
bypass. The first trial in this area, a RCT (TXA vs no TXA) in abdominal surgery, has only
just started recruiting (Tranexamic Acid to Reduce Delirium After Gastrointestinal Surgery:
the TRIGS-D Trial; clinicaltrials.gov).
The statistical methods will be determined once data distribution is known; the
interdependence of primary and secondary outcome measures will be determined by multivariate
regression analysis.
At this stage it is not possible to devise a prospective randomised controlled trial similar
the TRIGS-D study in cardiac surgery as giving TXA is considered standard of care. It might
be possible, however, to design a RCT comparing different TXA dosing regimens once the the
results of this retrospective analysis are available.
