What'S New in SHOCK, AUGUST 2017?
Continuing on this theme, Honickel et al. (2) inform us on the reversal of direct oral anticoagulants (DOACs) in animal models. As the use of DOACs such as direct thrombin and factor Xa inhibitors increase in use, reversal of these agents in patients with bleeding after injury or in need of emergency surgery represents a challenge to clinicians. Strategies for reversal are evolving and strong evidence in support of specific inhibitors is lacking. The authors nicely review available reversal agents for DOACs, both those in clinical and preclinical phases of use. They then review 26 preclinical animal studies and conclude with some worthy key points including: the need for standardized animal models and outcomes; the lower cost and higher output of small animal models but that larger animal modes more closely mimic human blood loss and hemodynamics; the need for awareness of species-specific differences in response to DOACs and their reversal; and the plea that blood loss and not laboratory values be the preferred primary endpoint in studies of reversal of DOACs.
Since we are discussing bleeding, let us move onto our next debate in this month's Shock related to the use of cryopreserved red blood cells. Cryopreserved cells are frozen within several days of donation and have the advantage of prolonged storage while frozen and after thawing. Chang et al. (3) previously reported that the post-thaw characteristics of cryopreserved units are not comparable to fresh red cells and that the development of the red cell storage lesion may actually be enhanced. In this month's Shock, Preston et al. (4) point out that a major mechanism of the red blood cell storage lesion is the accumulation of oxidative stress, one not assessed by Chang et al. (3). These authors measured the oxidation-reduction potential (ORP) in young and old units of traditionally stored blood and found that the older units accumulated more ORP during storage than younger units and suggested such a measurement be considered point of care testing. Chang and Pritts (5) agreed that ORP should be further explored to evaluate this measurement under various storage periods and conditions. I think it was a win-win!
Switching now from global disturbances to organ-specific injury, we learn from Zhu et al. (6) that an imbalance in plasma human neutrophil elastase (HNE) and the endogenous proteinase inhibitor, elafin (P13), can help prognosticate outcome in patients with acute respiratory distress syndrome (ARDS). These authors performed a prospective observational study of 167 patients with ARDS in China. HNE and P13 were measured over time and found to inversely correlate with survival; a higher HNE was found in non-survivors and higher P13 in survivors of ARDS.