Donald A. Reiff

The relationship of blood product ratio to mortality: survival benefit or survival bias?

BACKGROUND Recent studies show an apparent survival advantage associated with the administration of higher cumulative ratios of fresh frozen plasma (FFP) to packed red blood cells (PRBC). It remains unclear how temporal factors and survival bias may influence these results. The objective of this study was to evaluate the temporal relationship between blood product ratios and mortality in massively transfused trauma patients. METHODS Patients requiring massive transfusion (>10 units of PRBC within 24 hours of admission) between 2005 and 2007 were identified (n = 134). In-hospital mortality was compared between patients receiving high (>1:2) versus low (<1:2) FFP:PRBC ratios with a regression model, using the FFP:PRBC ratio as a fixed value at 24 hours (method I) and as a time-varying covariate (method II). RESULTS The FFP:PRBC ratio for all patients was low early and increased over time. Sixty-eight percent of total blood products were given and 54% of deaths occurred during the first 6 hours. Using method I, patients receiving a high FFP:PRBC ratio (mean, 1:1.3) by 24 hours had a 63% lower risk of death (RR, 0.37; 95% CI, 0.22-0.64) compared with those receiving a low ratio (mean, 1:3.7). However, this association was no longer statistically significant (RR, 0.84; 95% CI, 0.47-1.50) when the timing of component product transfusion was taken into account (method II). CONCLUSIONS 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.

Transfusions in the less severely injured: does age of transfused blood affect outcomes?

BACKGROUND Prior studies have demonstrated that transfusion of older stored blood is associated with an increased risk of multiple organ failure, infection, and death. These reports were primarily comprised of severely injured patients, and it remains unknown whether this phenomenon is observed in relatively less injured patients. The purpose of this study was to evaluate the association between the age of stored blood and the morbidity and mortality in a mild to moderately injured patient cohort. METHODS Blunt trauma patients with Injury Severity Score <25 admitted to a Trauma Intensive Care Unit during 7.5 years who received no blood during the first 48 hours of hospitalization were selected for inclusion. Patients who died within 48 hours of admission were excluded from analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the association between morbidity or mortality and the age and amount of blood transfused (>48 hours postadmission), adjusted for age, sex, injury severity, thoracic injury, mechanical ventilation, and transfusion volume. RESULTS During 7.5 years, 1,624 patients met the study criteria. The mean Injury Severity Score was 14.4. Receipt of blood stored beyond 2 weeks was associated with mortality (OR 1.12 [CI 1.02-1.23]), renal failure (OR 1.18 [CI 1.07-1.29]), and pneumonia (OR 1.10 [CI 1.04-1.17]). No such associations were identified, however, concerning the transfusion of blood with a lesser storage age. CONCLUSION In a mild to moderately injured intensive care unit patient cohort, the receipt of blood stored beyond 2 weeks was independently associated with mortality, renal failure, and pneumonia. The deleterious effect of older blood on patient outcome does not appear to be limited to the severely injured.

Gender differences in mortality following burn injury.

Clinical and experimental studies have demonstrated higher mortality following nonthermal trauma among males compared with females. To date, few clinical retrospective studies have focused on gender differences in outcome following burn injury with respect to age. All patients admitted to the University of Alabama at Birmingham (UAB) Burn Center between January 1994 and December 2000 were selected for inclusion in the study. Gender differences in demographic, clinical, and outcome characteristics were compared. Unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the association between mortality and gender, both overall and stratified by age. Over the 7-year study period, 1229 males and 382 females were admitted to the UAB Burn Center, and mortality rates were 7.2% and 13.4%, respectively (P = 0.0002). Female patients were more likely to be older, of the black race, and in poorer health. In addition, females were more likely to suffer flame and scald burns. The association between mortality and gender was modified by age. Up to age 60, mortality rates among females were over twice that of males (OR 2.3, 95% CI 1.4–3.8); however, no difference was noted among those 60 and older (OR 0.9, 95% CI 0.5–1.6). These associations persisted following adjustment for potentially confounding variables. Causes and timing of death were similar for males and females. Women less than 60 years of age who sustain burn injuries have an increased risk of death compared with males. Differences in the natural history of nonthermal trauma and burn injury may provide insight regarding these divergent findings.

Duration of red cell storage influences mortality after trauma.

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.

Traumatic brain injury is associated with the development of deep vein thrombosis independent of pharmacological prophylaxis.

INTRODUCTION Deep venous thrombosis (DVT) is common among trauma patients. If left untreated it may result in lethal pulmonary thromboembolism. Previous studies have suggested that intracranial hemorrhage serves as an independent risk factor for the development of DVT. These studies were not able to exclude anticoagulation therapy as a confounding variable in their analysis. Our objective was to determine the association of traumatic brain injury (TBI) to the formation of DVT irrespective of the use of anticoagulation therapy. METHODS All patients admitted to an academic level I Trauma Center between 2000 and 2007 with blunt or penetrating injuries were selected for inclusion in this study. Patients who died or who were discharged within 24 hours of admission were excluded in the analysis. TBI was defined as any intraparenchymal hemorrhage or extra-axial intracranial bleeding identified on radiographic imaging or both. Anticoagulation therapy was defined as the uninterrupted use of either subcutaneous lovenox or heparin. Risk ratios and 95% confidence intervals compared the risk of DVT among patients with and without TBI according to the initiation of anticoagulation therapy (no therapy, <24 hours, 24-48 hours, and >48 hours) adjusted for age, gender, race, injury severity, mechanism of injury, spinal injury, and lower extremity fracture. RESULTS Irrespective of the time of initiation of pharmacologic prophylaxis, TBI is independently associated with the formation of DVT. A threefold to fourfold increased risk of DVT formation is consistent across all prophylaxis groups among patients with TBI. CONCLUSION The incidence of DVT among injured patients with TBI is significantly higher than those patients without head injury independent of anticoagulation therapy. Rigorous surveillance to detect DVT among trauma patients with TBI should be undertaken and where appropriate alternate means for pulmonary thromboembolism prevention used.

Effectiveness of an Early Mobilization Protocol in a Trauma and Burns Intensive Care Unit: A Retrospective Cohort Study

Background Bed rest and immobility in patients on mechanical ventilation or in an intensive care unit (ICU) have detrimental effects. Studies in medical ICUs show that early mobilization is safe, does not increase costs, and can be associated with decreased ICU and hospital lengths of stay (LOS). Objective The purpose of this study was to assess the effects of an early mobilization protocol on complication rates, ventilator days, and ICU and hospital LOS for patients admitted to a trauma and burn ICU (TBICU). Design This was a retrospective cohort study of an interdisciplinary quality-improvement program. Methods Pre– and post–early mobility program patient data from the trauma registry for 2,176 patients admitted to the TBICU between May 2008 and April 2010 were compared. Results No adverse events were reported related to the early mobility program. After adjusting for age and injury severity, there was a decrease in airway, pulmonary, and vascular complications (including pneumonia and deep vein thrombosis) post–early mobility program. Ventilator days and TBICU and hospital lengths of stay were not significantly decreased. Limitations Using a historical control group, there was no way to account for other changes in patient care that may have occurred between the 2 periods that could have affected patient outcomes. The dose of physical activity both before and after the early mobility program were not specifically assessed. Conclusions Early mobilization of patients in a TBICU was safe and effective. Medical, nursing, and physical therapy staff, as well as hospital administrators, have embraced the new culture of early mobilization in the ICU.

Incidence and characteristics of motor vehicle collision-related blunt thoracic aortic injury according to age.

BACKGROUND Motor vehicle collision-related blunt thoracic aorta injury (BAI) is rare and highly lethal. Vascular disease as related to advancing age potentially subjects older adults to increased risk of BAI; the mechanisms associated with such injuries may be different as compared with younger adults. The goal of the present study is to test this hypothesis using population-based data. METHODS The 1995 to 1999 National Automotive Sampling System data files were used. The National Automotive Sampling System is a national probability sample of passenger vehicles involved in police-reported tow-away crashes. BAI was defined according to the Abbreviated Injury Scale codes. Among those with BAI, information on occupant (age, seating position, restraint use), collision (collision type, delta-V, vehicle intrusion), and outcome characteristics were obtained and compared according to age. RESULTS The overall incidence of BAI was 6.8 per 10,000 occupants and there was a steady increase in the BAI rate for advancing decades of life. The proportion of occupants with BAI who die at the scene of the collision is relatively consistent across all age groups ( approximately 85%). Among those who survive to receive medical care, ultimate survival is lowest among those aged 60 and older. Near-side collisions were responsible for more BAI among older adults than other age groups (50% vs. 20.6%, p < or = 0.05). Older adults sustained BAI in collisions with lower delta-V values compared with younger persons (p < or = 0.05). CONCLUSION Older adults have the highest rate of motor vehicle collision-related BAI, and their injuries tend to occur in less severe collisions. A high level of suspicion for BAI among older adults should not be reserved for high-energy collisions only.

Detailed description of all deaths in both the shock and traumatic brain injury hypertonic saline trials of the Resuscitation Outcomes Consortium

OBJECTIVE To identify causes and timing of mortality in trauma patients to determine targets for future studies. BACKGROUND In trials conducted by the Resuscitation Outcomes Consortium in patients with traumatic hypovolemic shock (shock) or traumatic brain injury (TBI), hypertonic saline failed to improve survival. Selecting appropriate candidates is challenging. METHODS Retrospective review of patients enrolled in multicenter, randomized trials performed from 2006 to 2009. Inclusion criteria were as follows: injured patients, age 15 years or more with hypovolemic shock [systolic blood pressure (SBP) ≤ 70 mm Hg or SBP 71-90 mm Hg with heart rate ≥ 108) or severe TBI [Glasgow Coma Score (GCS) ≤ 8]. Initial fluid administered was 250 mL of either 7.5% saline with 6% dextran 70, 7.5% saline or 0.9% saline. RESULTS A total of 2061 subjects were enrolled (809 shock, 1252 TBI) and 571 (27.7%) died. Survivors were younger than nonsurvivors [30 (interquartile range 23) vs 42 (34)] and had a higher GCS, though similar hemodynamics. Most deaths occurred despite ongoing resuscitation. Forty-six percent of deaths in the TBI cohort were within 24 hours, compared with 82% in the shock cohort and 72% in the cohort with both shock and TBI. Median time to death was 29 hours in the TBI cohort, 2 hours in the shock cohort, and 4 hours in patients with both. Sepsis and multiple organ dysfunction accounted for 2% of deaths. CONCLUSIONS Most deaths from trauma with shock or TBI occur within 24 hours from hypovolemic shock or TBI. Novel resuscitation strategies should focus on early deaths, though prevention may have a greater impact.

Injury rates among restrained drivers in motor vehicle collisions: The role of body habitus

BACKGROUND Previous studies have examined the independent effects of occupant height, obesity, and body mass index in motor vehicle collisions and identified related injury patterns. The hypothesis of this study was that as the drivers body habitus diverges from the 50% percentile male Hybrid III Crash Dummy (H3CD), the frequency of injury changes. METHODS The 1995 to 1999 National Automotive Sampling System Crashworthiness Data System was used. Study entry was limited to restrained drivers who were then subdivided into height and weight categories. Incidence rates were calculated for injuries to selected body regions as defined by the Abbreviated Injury Scale for overall, frontal, and drivers side collisions. RESULTS When grouped according to height and weight as descriptors of body habitus, injury rates for restrained drivers were increased as well as decreased in several subgroups. This association was seen in overall, frontal, and drivers side collisions. CONCLUSION The H3CD plays a major role in vehicular cabin interior design and crash testing. For drivers with a body habitus different from that of the H3CD, the vehicle cabin/body fit changes and the safety features may perform differently, which could account for these observations.

Identifying Injuries and Motor Vehicle Collision Characteristics that Together Are Suggestive of Diaphragmatic Rupture

BACKGROUND Diaphragmatic rupture (DR) remains a diagnostic challenge because of the lack of an accurate test demonstrating the injury. Our purpose was to identify motor vehicle collision (MVC) characteristics and patient injuries that collectively could identify the presence of a DR. METHODS The National Automotive Sampling System was used to identify occupants involved in MVCs from 1995 to 1999 who sustained abdominal (Abbreviated Injury Scale score >or= 2) and/or thoracic injuries (Abbreviated Injury Scale score >or= 2). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to quantify the association between patient injuries, vehicle collision characteristics, and DR. Sensitivity and specificity were also calculated to determine the ability of organ injury and MVC characteristics to correctly classify patients with and without DR. RESULTS Overall, occupants sustaining a DR had a significantly higher delta-V (DeltaV) (49.8 kilometers per hour [kph] vs. 33.8 kph, p< 0.0001) and a greater degree of occupant compartment intrusion (70.6 cm vs. 48.3 cm, p< 0.0001). Specific abdominal and thoracic organ injuries were associated with DR, including thoracic aortic tears (OR, 5.2; 95% CI, 2.2-12.5), splenic injury (OR, 8.4; 95% CI, 3.9-17.8), pelvic fractures (OR, 4.7; 95% CI, 2.7-8.0), and hepatic injuries (OR, 4.2; 95% CI, 1.7-10.6). Combining frontal or near-side lateral occupant compartment intrusion >or= 30 cm or DeltaV >or= 40 kph with specific organ injuries generated a sensitivity for indicating the likelihood of diaphragm injury ranging from 68% to 89%. Patients with any of the following characteristics had a sensitivity for detecting DR of 91%: splenic injury, pelvic fracture, DeltaV >or= 40 kph, or occupant compartment intrusion from any direction >or= 30 cm. CONCLUSION Specific MVC characteristics combined with patient injuries have been identified that are highly suggestive of DR. For this subpopulation, additional invasive procedures including exploratory laparotomy, laparoscopy, or thoracoscopy may be warranted to exclude DR.