The model of cecal ligation and puncture (CLP) in rodents has been used extensively to investigate the clinical settings of sepsis and septic shock. This model produces a hyperdynamic, hypermetabolic state that can lead to a hypodynamic, hypometabolic stage, and eventual death. Blood cultures are positive for enteric organisms very early after CLP. The model has been widely used over the past 26 years and is highly versatile in adapting to a range of severity and testing objectives. It is inexpensive to prepare and technically straightforward. Aspects of sepsis research investigated using CLP include energetics, metabolism, resuscitation, antibiotic therapy, microbial factors, cardiovascular responses, immune function, mediator release, and cytokine expression patterns. The challenge of the small circulating blood volume in rodents can be overcome by using micromethods that enable analysis of small volumes, or alternatively, by using a large number of animals to obtain serial samples.

Similar to previous studies, an association between higher FFP:PRBC ratios at 24 hours and improved survival was observed. However, after adjustment for survival bias in the analysis, the association was no longer statistically significant. Prospective trials are necessary to evaluate whether hemostatic resuscitation is clinically beneficial.

Although larger volumes of blood, irrespective of age, are associated with increased odds of mortality, the transfusion of blood stored beyond 2 weeks appears to potentiate this association despite a practice of universal leukoreduction. For patients who receive relatively smaller transfusion volumes, blood age appears to have no effect on mortality.

Background Although previous studies have identified an association between the transfusion of relatively older red blood cells (RBCs) (storage ≥14 days) and adverse outcomes, they are difficult to interpret because the majority of patients received a combination of old and fresh RBC units. To overcome this limitation, we compared in-hospital mortality among patients who received exclusively old versus fresh RBC units during the first 24 hours of hospitalization. Methods Patients admitted to a Level I trauma center between January 2000 and May 2009 who received ≥1 unit of exclusively old (≥14 days) vs. fresh (<14 days) RBCs during the first 24 hours of hospitalization were identified. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for the association between mortality and RBC age, adjusted for patient age, Injury Severity Score, gender, receipt of fresh frozen plasma or platelets, RBC volume, brain injury, and injury mechanism (blunt or penetrating). Results One thousand six hundred forty-seven patients met the study inclusion criteria. Among patients who were transfused 1 or 2 RBC units, no difference in mortality with respect to RBC age was identified (adjusted RR, 0.97; 95% CI, 0.72–1.32). Among patients who were transfused 3 or more RBC units, receipt of old versus fresh RBCs was associated with a significantly increased risk of mortality, with an adjusted RR of 1.57 (95% CI, 1.14–2.15). No difference was observed concerning the mean number of old versus fresh units transfused to patients who received 3 or more units (6.05 vs. 5.47, respectively; p = 0.11). Conclusion In trauma patients undergoing transfusion of 3 or more RBC units within 24 hour of hospital arrival, receipt of relatively older blood was associated with a significantly increased mortality risk. Reservation of relatively fresh RBC units for the acutely injured may be advisable.