David A. Hampton

Prehospital intravenous fluid is associated with increased survival in trauma patients.

BACKGROUND Delivery of intravenous crystalloid fluids (IVF) remains a tradition-based priority during prehospital resuscitation of trauma patients. Hypotensive and targeted resuscitation algorithms have been shown to improve patient outcomes. We hypothesized that receiving any prehospital IVF is associated with increased survival in trauma patients compared with receiving no prehospital IVF. METHODS Prospective data from 10 Level 1 trauma centers were collected. Patient demographics, prehospital IVF volume, prehospital and emergency department vital signs, lifesaving interventions, laboratory values, outcomes, and complications were collected and analyzed. Patients who did or did not receive prehospital IVF were compared. Tests for nonparametric data were used to assess significant differences between groups (p ⩽ 0.05). Cox regression analyses were performed to determine the independent influence of IVF on outcome and complications. RESULTS The study population consisted of 1,245 trauma patients; 45 were excluded owing to incomplete data; 84% (n = 1,009) received prehospital IVF, and 16% (n = 191) did not. There was no difference between the groups with respect to sex, age, and Injury Severity Score (ISS). The on-scene systolic blood pressure was lower in the IVF group (110 mm Hg vs. 100 mm Hg, p < 0.04) and did not change significantly after IVF, measured at emergency department admission (110 mm Hg vs. 105 mm Hg, p = 0.05). Hematocrit/hemoglobin, fibrinogen, and platelets were lower (p < 0.05), and prothrombin time/international normalized ratio and partial thromboplastin time were higher (p < 0.001) in the IVF group. The IVF group received a median fluid volume of 700 mL (interquartile range, 300–1,300). The Cox regression revealed that prehospital fluid administration was associated with increased survival (hazard ratio, 0.84; 95% confidence interval, 0.72–0.98; p = 0.03). Site differences in ISS and fluid volumes were demonstrated (p < 0.001). CONCLUSION Prehospital IVF volumes commonly used by PRospective Observational Multicenter Massive Transfusion Study (PROMMTT) investigators do not result in increased systolic blood pressure but are associated with decreased in-hospital mortality in trauma patients compared with patients who did not receive prehospital IVF. LEVEL OF EVIDENCE Therapeutic study, level IV.

Near infrared spectroscopy: clinical and research uses

Pulse oximetry is routinely used to measure hemoglobin saturation and is currently the gold standard to assess oxygenation in patients. Due to attenuation of infrared light by skin, bone, and other organs, pulse oximetry cannot assess end‐organ tissue oxygenation (StO2). Near infrared spectroscopy (NIS) penetrates a broad range of tissues and utilizes reflection rather than direct transmission between an emitter and receiver pair. NIS is able to measure StO2 and assess end‐organ perfusion in a variety of applications.

Traumatic brain injury is not associated with coagulopathy out of proportion to injury in other body regions.

BACKGROUND Coagulopathy following trauma is associated with poor outcomes. Traumatic brain injury has been associated with coagulopathy out of proportion to other body regions. We hypothesized that injury severity and shock determine coagulopathy independent of body region injured. METHODS We performed a prospective, multicenter observational study at three Level 1 trauma centers. Conventional coagulation tests (CCTs) and rapid thrombelastography (r-TEG) were used. Admission vital signs, base deficit (BD), CCTs, and r-TEG data were collected. The Abbreviated Injury Scale (AIS) score and Injury Severity Score (ISS) were obtained. Severe injury was defined as AIS score greater than or equal to 3 for each body region. Patients were grouped according to their dominant AIS region of injury. Dominant region of injury was defined as the single region with the highest AIS score. Patients with two or more regions with the same greatest AIS score and patients without a region with an AIS score greater than or equal to 3 were excluded. Coagulation parameters were compared between the dominant AIS region. Significant hypoperfusion was defined as BD greater than or equal to 6. RESULTS Of the 795 patients enrolled, 462 met criteria for grouping by dominant AIS region. Patients were predominantly white (59%), were male (75%), experienced blunt trauma (71%), and had a median ISS of 25 (interquartile range, 14–29). Patients with BD greater than or equal to 6 (n = 110) were hypocoagulable by CCT and r-TEG compared with patients with BD less than 6 (n = 223). Patients grouped by dominant AIS region showed no significant differences for any r-TEG or CCT parameter. Patients with BD greater than or equal to 6 demonstrated no difference in any r-TEG or CCT parameter between dominant AIS regions. CONCLUSION Coagulopathy results from a combination of tissue injury and shock independent of the dominant region of injury. With the use of AIS as a measure of injury severity, traumatic brain injury was not independently associated with more profound coagulopathy. LEVEL OF EVIDENCE Epidemiologic study, level III.

Cryopreserved red blood cells are superior to standard liquid red blood cells.

BACKGROUND Liquid preserved packed red blood cell (LPRBC) transfusions are used to treat anemia and increase end-organ perfusion. Throughout their storage duration, LPRBCs undergo biochemical and structural changes collectively known as the storage lesion. These changes adversely affect perfusion and oxygen off-loading. Cryopreserved RBCs (CPRBC) can be stored for up to 10 years and potentially minimize the associated storage lesion. We hypothesized that CPRBCs maintain a superior biochemical profile compared with LPRBCs. METHODS This was a prospective, randomized, double-blinded study. Adult trauma patients with an Injury Severity Score (ISS) greater than 4 and an anticipated 1-U to 2-U transfusion of PRBCs were eligible. Enrolled patients were randomized to receive either CPRBCs or LPRBCs. Serum proteins (haptoglobin, serum amyloid P, and C-reactive protein), proinflammatory and anti-inflammatory cytokines, d-dimer, nitric oxide, and 2,3-DPG concentrations were analyzed. Mann-Whitney U-test and Wilcoxon rank sum test were used to assess significance (p < 0.05). RESULTS Fifty-seven patients were enrolled (CPRBC, n = 22; LPRBC, n = 35). The LPRBC group’s final interleukin 8, tumor necrosis factor &agr;, and d-dimer concentrations were elevated compared with their pretransfusion values (p < 0.05). After the second transfused units, 2,3-DPG was higher in the patients receiving CPRBCs (p < 0.05); this difference persisted throughout the study. Finally, serum protein concentrations were decreased in the transfused CPRBC units compared with LPRBC (p < 0.01). CONCLUSION CPRBC transfusions have a superior biochemical profile: an absent inflammatory response, attenuated fibrinolytic state, and increased 2,3-DPG. A blood banking system using both storage techniques will offer the highest-quality products to critically injured patients virtually independent of periodic changes in donor availability and transfusion needs. LEVEL OF EVIDENCE Therapeutic study, level II.

Comparison of the hemostatic efficacy of low-volume lyophilized plasma reconstituted using sterile water, lactated Ringer's, normal saline, and Hextend solutions.

BACKGROUND Low-volume ascorbic acid–buffered reconstituted lyophilized plasma (LP) provides logistic advantages, reduces the risks for large-volume resuscitation, modulates inflammation, and is equally effective for hemostatic resuscitation as full-volume LP. We compared the physiologic effects of resuscitation using LP reconstituted with sterile water (LP-SW), lactated Ringer’s solution (LP-LR), normal saline (LP-NS), and Hextend (LP-Hx). METHODS Plasma was collected from swine, lyophilized, and then reconstituted into four test solutions: LP-SW, LP-LR, LP-NS, or LP-Hx. Forty swine were anesthetized and subjected to a validated model of polytrauma and hemorrhagic shock (including a Grade V liver injury), then randomized to receive one of the four test solutions. Physiologic parameters, blood loss, lactate, and hematocrit were followed up. Coagulation status was evaluated using thrombelastography. Inflammatory mediator expression was evaluated by multiplex serum assay. RESULTS Forty animals were included in the study (10 animals per group). One animal died following LP-Hx resuscitation. There was less blood loss in the LP-SW and LP-LR groups compared with the LP-NS and LP-Hx groups (p < 0.05). The LP-SW group exhibited less early coagulopathic changes by thrombelastography, and the LP-Hx group had persistently elevated international normalized ratios at the end of the study period (p < 0.05). Serum interleukin 6 was lower after 4 hours in the LP-SW group compared with LP-NS (p < 0.05). CONCLUSION Resuscitation using low-volume LP-SW and LP-LR buffered with ascorbic acid confers an anti-inflammatory benefit and results in less blood loss. Sterile water is a safe, cost-effective, and universally available fluid for creating a low-volume hemostatic LP resuscitation solution.

Reconstitution fluid type does not affect pulmonary inflammation or DNA damage following infusion of lyophilized plasma.

BACKGROUND Dysfunctional inflammation following traumatic hemorrhage can lead to multiple-organ failure and death. In our polytrauma swine model, lyophilized plasma (LP) reconstituted with sterile water and ascorbic acid suppressed systemic inflammation and attenuated DNA damage. However, it remains unknown whether the inflammatory response is affected by the type of fluid used to reconstitute LP. We hypothesized that common resuscitation fluids such as normal saline (LP-NS), lactated Ringer’s solution (LP-LR), Hextend (LP-HX), or sterile water (LP-SW) would yield similar inflammation profiles and DNA damage following LP reconstitution and transfusion. METHODS This was a randomized, prospective, blinded animal study. LP was reconstituted to 50% of original volume with NS, LR, HX, or SW buffered with 15-mM ascorbic acid. Forty swine were subjected to a validated model of polytrauma, hemorrhagic shock, and Grade V liver injury and resuscitated with LP. Serum interleukin 6 (IL-6), IL-10, plasma C-reactive protein, and 8-hydroxy-2-deoxyguanosine concentrations were assessed for systemic inflammation and DNA damage at baseline, 2 hours, and 4 hours following liver injury. Lung inflammation was evaluated by Real Time Polymerize Chain Reaction (RT-PCR). RESULTS Reconstituted LP pH was similar between groups before resuscitation. IL-6 and IL-10 increased at 2 hours and 4 hours compared with baseline in all groups (p < 0.017). DNA damage increased at 2 hours and 4 hours compared with baseline and from 2 hours to 4 hours in the LP-NS, LP-LR, and LP-SW groups (all p < 0.017). Animals resuscitated with LP-HX not only demonstrated increased DNA damage at 4 hours versus baseline but also had the lowest C-reactive protein level at 2 hours and 4-hours (p < 0.017). Overall, differences between groups were similar for DNA damage and lung inflammation. CONCLUSION Reconstitution fluid type does not affect inflammatory cytokine profiles or DNA damage following LP transfusion in this swine polytrauma model. Based on universal availability, these data suggest that sterile water is the most logical choice for LP reconstitution in humans. LEVEL OF EVIDENCE Prognostic, level II.