Age of transfused blood in critically ill adults. Lacroix J, Hébert PC, Fergusson DA, Tinmouth A, Cook DJ, Marshall JC, Clayton L, McIntyre L, Callum J, Turgeon AF, Blajchman MA, Walsh TS, Stanworth SJ, Campbell H, Capellier G, Tiberghien P, Bardiaux L, van de Watering L, van der Meer NJ, Sabri E, Vo D; ABLE Investigators; Canadian Critical Care Trials Group. N Engl J Med. 2015 Apr 9;372(15):1410-8.
This multicenter, randomized, blinded trial explores the effect of transfusion of fresh (stored for less than 8 days) versus standard-issue (stored less than 42 days) red blood cells on the 90-day mortality of critically ill patients. Previous studies on the subject have shown conflicting results with a systematic review of 18 observational studies and three randomized control studies suggesting that transfusion of older cells was associated with an increased mortality, while the Age of Blood Evaluation pilot trial showed a trend toward increased risk of death or life-threatening complications among patients receiving fresh blood. The trial represented by this paper seeks to clarify these conflicting results among the population of the critically ill.
The study included patients admitted to the intensive care units of 64 tertiary centers in Canada, the United Kingdom, France, the Netherlands and Belgium between March 2009 and May 2014. Study participants were randomized to receive blood that had been stored for less than 8 days (6.1 ± 4.9 days)or blood that had been stored according to the usual transfusion practice (22.0 ±8.4 days). The assigned transfusion practices were continued until hospital discharge or 90 days after randomization, whichever occurred first.
Overall, 2430 patients were studied with 1211 in the fresh-blood group and 1219 in the standard-blood group, with 90-day mortality rates of 37.0% and 35.3%, respectively. No significant difference was found between the two groups (95% confidence interval, -2.1 to 4.9). There was also no significant difference in mortality between the two groups when stratified based on age, number of units transfused or APACHE II score.
The study results suggest that there is no need to change our current transfusion practices in favor of fresher packed red blood cells. The fact, however, that this study was performed in Canadian and European centers may limit its relevance to practices within the United States, where red blood cells are suspended in additive solution 3 as opposed to the SAGM-suspended cells used in this study. While both solutions have previously been found to result in similar red blood cell defects, we lack all the necessary data to apply the results of this study to the red cell preparation and storage practices in the United States.
The duration of intra-abdominal hypertension strongly predicts outcomes for the critically ill surgical patients: a prospective observational study. Kyoung KH, Hong SK. World J Emerg Surg. 2015 May 30;10:22.
This a prospective, observational, single-institution study that explores the relationship between daily measured intra-abdominal pressure and long-term outcomes among 46 surgical intensive care unit (SICU) patients at Asian Medical Center in Seoul, Korea between March and October 2009. Specifically, the correlation between the duration of intra-abdominal hypertension (IAH) and multiple prognostic factors, including length of hospital and ICU stay and 60-day mortality was explored. IAH was defined as a maximum intra-abdominal pressure (IAP) reading greater than 12 mmHg when IAP was measured three times daily via a urinary catheter filled with 25 mL of saline.
The injurious effects of elevated intra-abdominal pressure on multiple organ systems have been previously demonstrated. These include difficulty weaning from the ventilator and decreased renal blood flow and gastrointestinal motility resulting in acute kidney injury and delays in enteral feeding. In this study, the authors found that duration of IAH had a more significant effect on outcomes than development of IAH with multivariate logistic regression analysis confirming the duration of IAH as an independent predictor of 60-day mortality with an odds ratio of 1.196. The authors postulate that early recognition of IAH and possible surgical intervention could improve patient outcomes.
Fresh frozen plasma and spray-dried plasma mitigate pulmonary vascular permeability and inflammation in hemorrhagic shock. Potter DR, Baimukanova G, Keating SM, Deng X, Chu JA, Gibb SL, Peng Z, Muench MO, Fomin ME, Spinella PC, Kozar R, Pati S. J Trauma Acute Care Surg. 2015 Jun;78(6 Suppl 1):S7-S17.
Early administration of fresh frozen plasma (FFP) has previously been shown to improve survival in trauma patients requiring massive transfusion. Recent studies have suggested that FFP improves outcomes via direct action on endothelial tissue, decreasing permeability, inflammation and hemodynamic instability. However, the utility of FFP as a resuscitation measure has been limited in the setting of acute hemorrhagic shock by many factors, including the storage practices of FFP that require it to be frozen, thawed and cross-matched prior to transfusion. The authors of this study propose that use of a solvent detergent-treated pooled plasma product (SDP) from over 150 type AB donors resuscitated in a pH-adjusted phosphate buffer could offer a more convenient and equivalent resuscitation option to FFP. Previously, the authors have demonstrated that SDP and FFP have equivalent effects on endothelial cell function in in vitro assays.
In this study FFP, SDP and lactated Ringer’s (LR) solution were used in in vitro assays of endothelial cells, measuring the expression of multiple genes, including cytokines, chemokines and other markers of inflammation. Mice models of hemorrhagic shock were also used to compare pulmonary vascular permeability via histologic and immunofluourescent examination of lung tissue, including staining for expression of CD68, VE-cadherin and occludin, after resuscitation with FFP, SDP or LR.
The study demonstrates that FFP and SDP affect gene expression at relatively equivalent rates and reduce the permeability of the endothelial cell monolayer, whereas LR does not. The authors propose that, pending further study, SDP, which “can be stored at room temperature, transported easily, and reconstituted rapidly,” may have future cost and outcome benefits as a resuscitative measure in the traumatically injured patient suffering from hemorrhagic shock.