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Although modern humans left Africa multiple times over 100,000 years ago, those broadly ancestral to non-Africans dispersed less than 100,000 years ago 1 . Most models hold that these events occurred through green corridors created during humid periods because arid intervals constrained population movements 2 . Here we report an archaeological site-Shinfa-Metema 1, in the lowlands of northwest Ethiopia, with Youngest Toba Tuff cryptotephra dated to around 74,000 years ago-that provides early and rare evidence of intensive riverine-based foraging aided by the likely adoption of the bow and arrow. The diet included a wide range of terrestrial and aquatic animals. Stable oxygen isotopes from fossil mammal teeth and ostrich eggshell show that the site was occupied during a period of high seasonal aridity. The unusual abundance of fish suggests that capture occurred in the ever smaller and shallower waterholes of a seasonal river during a long dry season, revealing flexible adaptations to challenging climatic conditions during the Middle Stone Age. Adaptive foraging along dry-season waterholes would have transformed seasonal rivers into 'blue highway' corridors, potentially facilitating an out-of-Africa dispersal and suggesting that the event was not restricted to times of humid climates. The behavioural flexibility required to survive seasonally arid conditions in general, and the apparent short-term effects of the Toba supereruption in particular were probably key to the most recent dispersal and subsequent worldwide expansion of modern humans., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Laboratory-based evidence of coagulopathy (LC) is observed in 25-35% of trauma patients, but clinically-evident coagulopathy (CC) is not well described., Methods: Prospective observational study of adult trauma patients transported by helicopter from the scene to nine Level 1 trauma centers in 2015. Patients meeting predefined highest-risk criteria were divided into CC+ (predefined as surgeon-confirmed bleeding from uninjured sites or injured sites not controllable by sutures) or CC-. We used a mixed-effects, Poisson regression with robust error variance to test the hypothesis that abnormalities on rapid thrombelastography (r-TEG) and international normalized ratio (INR) were independently associated with CC+., Results: Of 1,019 highest-risk patients, CC+ (n=41, 4%) were more severely injured (median ISS 32 vs 17), had evidence of LC on r-TEG and INR, received more transfused blood products at 4 hours (37 vs 0 units), and had greater 30-day mortality (59% vs 12%) than CC- (n=978, 96%). The overall incidence of LC was 39%. 30-day mortality was 22% vs 9% in those with and without LC. In two separate models, r-TEG K-time >2.5 min (RR 1.3, 95% CI 1.1-1.7), r-TEG mA <55 mm (RR 2.5, 95% CI 2.0-3.2), platelet count <150 x 10 9 /L (RR 1.2, 95% CI 1.1-1.3), and INR >1.5 (RR 5.4, 95% CI 1.8-16.3) were independently associated with CC+. A combined regression model was not generated because too few patients underwent both r-TEG and INR., Conclusion: CC was rare compared to LC. CC was associated with poor outcomes and impairment of both clotting factor and platelet-mediated coagulation components., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Studies evaluating traumatic brain injury (TBI) patients have shown an association between prehospital (PH) intubation and worse outcomes. However, previous studies have used surrogates, e.g., Glasgow Coma Scale (GCS) score ≤8 and Abbreviated Injury Severity Scale (AIS) score ≥3, which may overestimate the true presence of TBI. This study evaluated the impact of PH intubation in patients with PH GCS score ≤8 and radiographically proven TBI., Methods: Trauma patients routed to a Level I trauma center over a 3-year period with blunt injury and PH GCS score ≤8 were included. PH and in-hospital records were linked and head computed tomography scans were assigned a Marshall Score (MS). Patients with TBI (MS >1) were categorized into groups based on intubation status (PH, emergency department [ED], and no intubation). Comparisons were made using analysis of variance and χ statistics. Mortality differences, crude and adjusted risk ratios (RRs), and 95% confidence intervals (CIs) were calculated using proportions hazards modeling., Results: Of 334 patients with PH GCS score ≤8, 149 (50%) had TBI by MS. Among the TBI patients, 42.7% of patients were PH intubated, 47.7% were ED intubated, and 9.4% were not intubated during the initial resuscitation. Intubated patients had lower ED GCS score (PH: 4.1 and ED: 5.9 vs. 14.0; p < 0.0001) compared with patients not intubated. Also PH intubated patients had higher mean Injury Severity Score (38.0 vs. 33.7 vs. 23.5, p < 0.001) when compared with ED intubated and nonintubated patients. None of the nonintubated patients had a MS >2. Mortality for TBI patients who required PH intubation was 46.9% and 41.4% among ED-intubated patients. The crude RR of mortality for PH compared with ED intubation was 1.13 (95% CI, 0.68-1.89), and remained nonsignificant (RR, 0.68; 95% CI, 0.36-1.19) when adjusted for key markers of injury severity., Conclusions: Patients with PH GCS score ≤8 and proven TBI had a high overall rate of intubation (>90%). PH intubation seems to be a marker for more severe injury and conveyed no increased risk for mortality over ED intubation.

Background: This study seeks to evaluate the relationship between the risk of symptomatic hemorrhage from ventriculostomy placement and International Normalized Ratio (INR) in patients who received a ventriculostomy after traumatic brain injury., Methods: Patients who received a ventriculostomy after traumatic brain injury between June 2007 and July 2008 were identified and their medical records were abstracted for information., Results: At the time of ventriculostomy placement, 32 patients had an INR<1.2, 26 patients had an INR 1.2 to 1.4, 12 patients had an INR 1.4 to 1.6, and one patient had an INR>1.6 (INR=1.61). No significant difference in the risk of hemorrhage between the groups was observed: 9.4%, 3.9%, 8.3%, and 0%, respectively (p=0.73). In a subgroup analysis of patients who received ventriculostomy in the Neurosurgical Intensive Care Unit within 24 hours of admission (n=54), the average time between admission and ventriculostomy placement in patients who did not receive fresh frozen plasma was 6.8 hours compared with 9.3 hours (p=0.03) for those who did., Conclusions: In this retrospective study, INRs between 1.2 and 1.6 appeared to be acceptable for a neurosurgeon to place an emergent ventriculostomy in a patient with traumatic brain injury.

Background: Intracranial pressure is routinely monitored in patients with severe traumatic brain injury (TBI). Patients with TBI sometimes develop hydrocephalus, requiring permanent cerebrospinal fluid (CSF) diversion., Objective: To quantify the need for permanent CSF diversion in patients with TBI., Methods: Patients who received a ventriculostomy after TBI between June 2007 and July 2008 were identified, and their medical records were abstracted to a database., Results: Sixteen of 71 patients (22.5%) receiving a ventriculostomy required a ventriculoperitoneal or ventriculoatrial shunt before discharge from the hospital. The average number of days between ventriculostomy and shunt was 18.3. Characteristics that predispose these patients to require permanent CSF diversion include the need for craniotomy within 48 hours of admission (odds ratio, 5.20; 95% confidence interval, 1.48-18.35) and history of culture-positive CSF (odds ratio, 5.52; 95% confidence interval, 1.19-25.52). Length of stay was increased in patients receiving permanent CSF diversion (average length of stay, 61 vs 31 days; P = .04). Patient discharge disposition was similar between shunted and nonshunted patients., Conclusion: In this retrospective study, 22% of TBI patients who required a ventriculostomy eventually needed permanent CSF diversion. Patients with TBI should be assessed for the need for permanent CSF diversion before discharge from the hospital. Care must be taken to prevent ventriculitis. Future studies are needed to evaluate more thoroughly the risk factors for the need for permanent CSF diversion in this patient population.

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.

Background: Serial computed tomography (CT) imaging of blunt splenic injury can identify the latent formation of splenic artery pseudoaneurysms (PSAs), potentially contributing to improved success in nonoperative management. However, it remains unclear whether the delayed appearance of such PSAs is truly pathophysiologic or attributable to imaging quality and timing. The objective of this study was to evaluate the influence of recent advancements in imaging technology on the incidence of the latent PSA., Methods: Consecutive patients with blunt splenic injury over 4.5 years were identified from our trauma registry. Follow-up CT was performed for all but low-grade injuries 24 hours to 48 hours after initial CT. Incidences of both early and latent PSA formation were reviewed and compared with respect to imaging technology (4-slice vs. >or=16-slice)., Results: A total of 411 patients were selected for nonoperative management of blunt splenic injury. Of these, 135 had imaging performed with 4-slice CT, and 276 had imaging performed with CTs of >=16-slice. Mean follow-up was 75 days (range, 1-1178 days) and 362 patients (88%) had follow-up beyond 7 days. Comparing 4-slice CT with >or=16-slice CT, there were no significant differences in the incidence of early PSA (3.7% vs. 4.7%; p = 0.91) or latent PSA (2.2% vs. 2.9%; p = 0.90). In both groups, latent PSAs accounted for approximately 38% of all PSAs observed. Splenic injury grade on initial CT was not associated with latent PSA (p = 0.54). Overall, the failure rate of nonoperative management was 7.3%. Overall mortality was 4.6%. No mortalities were related to splenic or other intra-abdominal injury., Conclusions: The incidences of both early and latent PSA have remained remarkably stable despite advances in CT technology. This suggests that latent PSA is not a result of imaging technique but perhaps a true pathophysiologic phenomenon. Injury grade is unhelpful concerning the prediction of latent PSA formation.

Background: Although contrast venography is the standard imaging method for inferior vena cava (IVC) filter insertion, intravascular ultrasound (IVUS) imaging is a safe and effective option that allows for bedside filter placement and is especially advantageous for immobilized critically ill patients by limiting resource use, risk of transportation, and cost. This study reviewed the effectiveness of a prospectively implemented algorithm for IVUS-guided IVC filter placement in this high-risk population., Methods: Current evidence-based guidelines were used to create a clinical decision algorithm for IVUS-guided IVC filter placement in critically ill patients. After a defined lead-in phase to allow dissemination of techniques, the algorithm was prospectively implemented on January 1, 2008. Data were collected for 1 year using accepted reporting standards and a quality assurance review performed based on intent-to-treat at 6, 12, and 18 months., Results: As defined in the prospectively implemented algorithm, 109 patients met criteria for IVUS-directed bedside IVC filter placement. Technical feasibility was 98.1%. Only 2 patients had inadequate IVUS visualization for bedside filter placement and required subsequent placement in the endovascular suite. Technical success, defined as proper deployment in an infrarenal position, was achieved in 104 of the remaining 107 patients (97.2%). The filter was permanent in 21 (19.6%) and retrievable in 86 (80.3%). The single-puncture technique was used in 101 (94.4%), with additional dual access required in 6 (5.6%). Periprocedural complications were rare but included malpositioning requiring retrieval and repositioning in three patients, filter tilt >/=15 degrees in two, and arteriovenous fistula in one. The 30-day mortality rate for the bedside group was 5.5%, with no filter-related deaths., Conclusions: Successful placement of IVC filters using IVUS-guided imaging at the bedside in critically ill patients can be established through an evidence-based prospectively implemented algorithm, thereby limiting the need for transport in this high-risk population., (Copyright (c) 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Acute rhinosinusitis is a common problem that could occur in space secondary to absence of gravity-dependent drainage or odontogenic or external sources of infection. The purpose of this study was to determine the efficacy of ultrasound to determine sinus fluid distribution levels in swine and to assess the accuracy of ultrasound in the animal during normal and microgravity conditions., Methods: Anesthetized swine had a catheter placed through a frontal bone window to allow aliquots of a viscous solution to be injected at 1 G (N = 4) or during brief microgravity parabolic flights (N = 4). Ultrasound examinations were performed with a high frequency probe during baseline and fluid-induced conditions., Results: There was a consistent air-fluid level interface seen on ultrasound examination with the injection of 1 ml of fluid during 1-G conditions. Microgravity conditions caused the rapid (< 10 s) dissolution of the air-fluid level associated with dispersion of the fluid to the walIs of the sinus cavity in a uniform fashion. The air-fluid interface was recreated with return to 1 G., Conclusions: Ultrasound is a reliable diagnostic test for assessing fluid levels; these experiments demonstrate the technique can be used during microgravity conditions with attention to altered fluid behavior in the absence of gravity.

Background: Although the "open abdomen" has likely contributed to improved outcomes in trauma patients, the challenge of subsequent fascial closure has emerged. Since mid 2004, we have incorporated Wittmann Patch staged abdominal closure into our management of the open abdomen. The purpose of this study was to evaluate the impact of this device on our incidence of fascial closure versus planned ventral hernia., Methods: Patients managed by open abdomen from 2001 through 2006 were identified from the trauma registry. Fascial closure immediately after definitive repair of injuries was defined as "early fascial closure." Continuation of the open abdomen beyond the definitive repair of injuries with subsequent fascial closure was defined as "delayed fascial closure." Since April 2004, the Wittmann Patch was uniformly employed in open abdomen management. Patients managed before the use of this device ("pre-Patch") were compared with those managed in the "Patch" era., Results: Fifty-six open abdomens were managed in the pre-Patch era and 103 were managed in the Patch era. In the pre-Patch era, 33 (59%) underwent early fascial closure, compared with 67 (65%) in the Patch era (p NS). For the remaining patients, the incidence of delayed fascial closure was significantly higher in those managed with the Wittmann Patch compared with those managed in the pre-Patch era (78% vs. 30%, p < 0.001). Planned ventral hernia was performed in 8 (8%) patients in the Patch era versus 16 (29%) patients in the pre-Patch era (p < 0.001). Abdominal complications were similar between groups (11% vs. 9%, p NS)., Conclusions: Incorporating the Wittmann Patch into a clinical pathway for management of the open abdomen has contributed to an increased incidence of delayed fascial closure. Abdominal complications were similar in both groups, suggesting that the device is not only efficacious, but also relatively safe.

There are several candidate neuroprotective agents that have been shown in preclinical testing to improve outcomes following traumatic brain injury (TBI). Xiao and colleagues have performed an in hospital, double blind, randomized, controlled clinical trial utilizing progesterone in the treatment of patients sustaining TBI evaluating safety and long term clinical outcomes. These data, combined with the results of the previously published ProTECT trial, show progesterone to be safe and potentially efficacious in the treatment of TBI. Larger phase III trials will be necessary to verify results prior to clinical implementation. Clinical trials networks devoted to the study of TBI are vital to the timely clinical testing of these candidate agents and need to be supported.

Background: Chest computed tomography (CT) is an excellent screening tool for blunt aortic injuries (BAIs). Aortography is considered the "gold standard" for diagnosis. Recent evidence suggests that new-generation, multislice, helical CT technology can accurately diagnose BAI., Methods: A retrospective review of aortograms performed to evaluate for BAI was compared with the results of CT and operative findings. BAIs definitively diagnosed by CT alone were also studied., Results: Between July 1, 1996, and June 30, 2002, 113 aortograms were obtained, with 28 BAI cases confirmed. Of these, 27 were congruently diagnosed by CT. Only one computed tomographic scan diagnostic for BAI had a subsequent negative aortogram. Seventeen BAIs were diagnosed with CT alone. Ten were confirmed operatively and seven were treated nonoperatively because of age, comorbid conditions, severity of injury, or the presence of small intimal defects., Conclusion: CT technology has evolved to allow for the definitive diagnosis and treatment of BAI. Aortography should still be used where new-generation CT is not available.

Background: Blunt cerebrovascular artery injury (BCI) remains difficult to diagnose but is recognized with increasing frequency after motor vehicle collisions (MVCs). Failure to detect this injury in a timely fashion can be devastating. Criteria that can be used to heighten the suspicion of this injury have been suggested; however, more encompassing screening has been recommended. To address this need, we sought to describe occupant, vehicle, and collision characteristics among MVC occupants who sustained a BCI., Methods: All cases of BCI identified in the National Automotive Sampling System Crashworthiness Data System, a national probability sample of passenger vehicles involved in police-reported tow-away MVCs, between 1993 and 2001 were selected. Information on occupant (e.g., demographics, seating position, and restraint use), collision (e.g., collision type and severity), and vehicle characteristics were obtained and summarized using descriptive statistics., Results: Nine-hundred forty individuals with BCI were identified in the Crashworthiness Data System data files. Over half were belted (57.4%) and 82.3% had airbag deployment; 16.2% were partially or completely ejected from the vehicle. Head and thoracic injuries were common (44.4% and 40.8%, respectively); 27.8% sustained a cervical spine fracture and 21.0% sustained a soft-tissue injury to the neck. The mean Injury Severity Score was 33.6. The case fatality rate was 44.5%. The majority of BCI occupants were drivers (76.0%). Among belted occupants, the lap/shoulder was the most commonly attributed as the injury source (61.4%). Among unbelted occupants, frequent injury sources included air bags (15.0%), windshield (13.7%), and other interior objects. With respect to collision characteristics, the average change in velocity (Delta V) was 43.3 km/h. The majority of collisions were frontal (76.2%)., Conclusion: This study indicates that BCI is both a rare and lethal injury typified by specific occupant and collision characteristics. These characteristics provide insight as to the cause of this injury that may aid in the evaluation and management of the blunt trauma patient at risk for BCI.

Although laboratory studies indicate that female rodents better tolerate the deleterious consequences of trauma and have higher survival rates than male rodents, it remains unclear whether a similar gender dimorphic pattern is evident in humans. In view of this, the association between gender and mortality in trauma patients admitted to a University Level I Trauma Center was assessed. All adult patients admitted to the University of Alabama at Birmingham Trauma Center with blunt or penetrating injury between July 1996 and March 2001 were selected for analysis. Patients were categorized by mechanism (blunt or penetrating), and odds ratios (ORs) were used to compare the risk of death among males compared with females. The ORs were stratified according to age and were adjusted for demographic, medical, and injury characteristics. Male blunt trauma patients <50 years old had a 2.5 times (95% CI 1.3-4.9) higher risk of death than females; however, for those > or = 50 years old, a smaller, nonstatistically significant difference was apparent (OR 1.4, 95% CI 0.8-2.3). Conversely, for penetrating trauma, males <50 years old exhibited an increased yet nonsignificant risk of death (OR 1.8, 95% CI 0.6-5.4), whereas those > or = 50 years old had a survival advantage (OR 0.1, 95% CI 0.02-0.5). Laboratory studies have demonstrated that estrogens are salutary and androgens are detrimental for survival following trauma-hemorrhage. The results of this study suggest that the physiologic pattern of premenopausal adult female sex hormones may provide a survival advantage in blunt trauma patients; however, the converse pattern prevails for the penetrating trauma patients.

Blunt abdominal aortic trauma occurs in up to 0.04% of all nonpenetrating traumas. Although uncommon, mortality from this injury ranges from 18% to 37%. Seat belt injury is associated with almost 50% of reported blunt abdominal aortic traumas. The authors present the case of a 21-year-old man, a restrained passenger who was involved in a high-speed motor vehicle accident. In the emergency room, he had obvious evidence of lap-belt injury. His peripheral pulses were normal and there was no pulsatile abdominal mass. Computer tomography (CT) revealed a large amount of free intraperitoneal fluid throughout with signs of mesenteric avulsion and fracture/dislocation of T11-T12. The patient underwent an exploratory laparotomy. Right hemicolectomy and resection of small bowel was performed. CT angiography revealed an aortic transection and surrounding pseudoaneurysm 2 cm above the aortic bifurcation. The patient returned to the operating room for endovascular repair. Via a right femoral cutdown, a 14 mm x 5.5 cm stent-graft was placed across the distal abdominal aorta. Follow-up arteriogram revealed complete obliteration of the pseudoaneurysm without evidence of leak. There were no complications related to the aortic stent-graft in the postoperative period. The patient was discharged in good condition. As this case demonstrates, endovascular repair of traumatic aortic injury is feasible and may represent an improved treatment in certain settings.

Our hypothesis was that clinical outcomes are improved and cost and hospital length of stay (LOS) reduced as a result of the opening of a closed trauma intensive care unit (ICU). We conducted a cross-sectional study in a university-affiliated Level I trauma center. Our study population comprised trauma patients admitted to the ICU between June 1, 1996 and July 1, 1998 for at least 24 hours and with an Injury Severity Score (ISS) >16 (excluding those with severe brain injury). The main outcome measures were changes in LOS and number of ventilator days, prevalence of complications, changes in patient charges, and hospital costs. Two hundred four patients were included [trauma ICU (TICU) 60, surgical ICU 144]. The two groups were not statistically different in age, ISS, mechanism of injury, infection rate, and mortality; however, the TICU patients had a lower number of ventilator hours (83.1 vs 100.0; P = 0.007), lower ICU LOS (9.4 vs 12.1 days; P = 0.06), and lower total hospital LOS (15.6 vs 22.3 days; P = 0.01). Although this was not of statistical significance TICU patients had lower hospital charges ($125,383 vs $152,994; P = 0.06) and lower cost per case ($42,306 vs $47,548; P = 0.35) for a net savings of $314,520 during the first 6 months of operation of the TICU. This study suggests that improved clinical outcomes and decreases in cost and LOS are directly related to the opening of a closed trauma ICU.

Hypothesis: Older patients (those aged > or = 70 years) who have experienced trauma have an increased risk of recurrent trauma. Demographic, medical, and functional factors are potential contributors to the risk of subsequent trauma among injured elderly patients., Design: Retrospective follow-up study., Participants: Study participants were derived from the Longitudinal Study of Aging, an extension of the 1984 National Health Interview Survey focusing on persons who were aged 70 years and older in 1984. A cohort of elderly patients participating in the Longitudinal Study of Aging and hospitalized for injury in 1985 (n = 100) was identified using Medicare hospital discharge data. An uninjured cohort (n = 401) was also identified from the Longitudinal Study of Aging and matched for age (1 year) and sex., Main Outcome Measures: Risk of admission for trauma among the injured cohort compared with the uninjured cohort and associations between demographic, medical, and functional characteristics and trauma recurrence., Results: Following adjustment for potential confounding factors, the injured cohort was 3.25 times more likely (95% confidence interval, 1.99-5.31) to be hospitalized for injury during the follow-up period compared with the uninjured cohort. Among the injured cohort, those at greatest risk of subsequent trauma included women and those with chronic medical conditions or functional impairments, the latter being the only factor independently associated with recurrence., Conclusions: Elderly patients who have experienced trauma are at increased risk of subsequent injury. Interventions to reduce the likelihood of trauma recurrence should focus on those with chronic illnesses and functional impairments.

Both vancomycin and third-generation cephalosporin use are believed to contribute to a rise in vancomycin-resistant enterococci (VRE) infections. In 1998, the largest number of VRE infections in our hospital occurred in the trauma/burn intensive care unit (TBICU), accounting for nearly 20% of hospital infections. In an attempt to control the VRE infection rate, antibiotic protocols for prophylaxis, empiric, and definitive therapy were initiated during the final quarter of 1998 to minimize cephalosporin use by the introduction of piperacillin/tazobactam. Therefore, we undertook a study of the VRE infection rate for the TBICU in relation to vancomycin, piperacillin/tazobactam, piperacillin, third-generation cephalosporin, and total cephalosporin use before and after efforts to limit cephalosporins. These data were compared to those in the medical and surgical intensive care units. During 1998, seven VRE infections occurred in the TBICU. Following initiation of antibiotic protocols, one case of VRE infection occurred in the subsequent month and no cases in the 17 months since. The decrease in the VRE infection rate corresponded with a significant increase in the use of piperacillin/tazobactam and a reduction in third-generation and total cephalosporin use. In contrast, cephalosporin use in the medical and surgical intensive care units remains significantly higher than in the TBICU, and neither unit has had a reduction in their VRE infection rates.

Inferior vena cava (IVC) injuries are potentially devastating insults that continue to be associated with high mortality despite advances in prehospital and in-hospital critical care. Between 1987 and 1996, 37 patients (32 males and 5 females; average age, 30 years) were identified from the trauma registry as having sustained IVC trauma. Overall mortality was 51 per cent (n = 19), with 13 intraoperative deaths and five patients dying within the first 48 hours. Blunt IVC injuries (n = 8) had a higher associated mortality than penetrating wounds (63% versus 48%). Of the 29 patients with penetrating IVC trauma, the wounding agent influenced mortality (shotgun-100% versus gunshot-43% versus stab-0%). Anatomical location of injury was also predictive of death [suprahepatic (n = 3)-100% versus retrohepatic (n = 9)-78% versus suprarenal (n = 6)-33% versus juxtarenal (n = 2)-50% versus infrarenal (n = 15)-33%]. A direct relationship existed between outcome and the number of associated injuries: nonsurvivors averaged four and survivors averaged three. Eighty per cent of patients sustaining four or more associated injuries died, by contrast to a 33 per cent mortality in those suffering less than four injuries. Physiological factors were also predictive of outcome. Patients in shock (systolic blood pressure < 80) on arrival had a higher mortality than those who were hemodynamically stable (76% versus 30%). Preoperative lactate levels were of prognostic value for death (> or = 4.0-59% versus < 4.0-0%), as was base deficit (< 4-22%, > or = 4, and < 10-36%, > or = 10-73%). Interestingly, neither time from injury to hospital arrival (47.4 minutes versus 33.0 minutes) nor time in the emergency department before surgery (45.6 minutes versus 42.6 minutes) differed between survivors and fatalities. Mortality remained high in the 34 patients who had operative control of their IVC injuries [lateral repair (n = 27)-44% versus ligation (n = 6)-66% versus Gortex graft (n = 1)-0%]. As wounding agent, anatomical location, associated injuries, and physiological status seem to most directly impact mortality, future efforts must focus both on establishing prevention programs directed at reducing the incidence of this injury, as well as on advancing the management of those who do survive to hospitalization, if we are to improve on the outcome of these devastating injuries.

The pathophysiologic sequence leading to respiratory failure after chest trauma can be an inevitable consequence of the primary injury or a secondary, mediator-driven inflammatory process. To distinguish between these alternatives, a simple cross-transfusion experiment was performed. A captive bolt gun injured the chest of anesthetized pigs that were mechanically ventilated with FiO2 = .21, .50, or .50 plus indomethacin (5 mg/kg intravenous; 15 min before injury). Tube thoracostomy immediately followed. After 30 min, blood from these injured donors was transfused into three matched groups of naive recipients (n = 8, 6, and 4, respectively) for a 33% exchange transfusion. Two control groups received blood from uninjured donors with tube thoracostomies only (FiO2 = .21, n = 7; FiO2 = .50, n = 10). Within 15-30 min after transfusion, in recipients from injured donors versus controls, lung compliance was decreased 20%, stroke volume and cardiac output were decreased 50%, and pulmonary vascular resistance was increased >300% (all p < .05). These changes recovered to baseline within 60-90 min. The stable metabolite of thromboxane A2, thromboxane B2, increased >500% in plasma within 15 min and remained elevated for >120 min. All responses were similar at 21 % or 50% O2, which suggests that hypoxia per se is not a cause of mediator production. All responses were eliminated by indomethacin. By 24 h, histologic changes included atelectasis in 3/3 recipients from injured donors versus 0/3 recipients from uninjured donors. We conclude that 1) blunt chest trauma releases blood borne mediators, including prostanoids; 2) these mediators can cause secondary cardiopulmonary changes in naive recipients similar to those produced by chest trauma; 3) the progression to trauma-induced respiratory failure is multifactorial; 4) early pharmacologic intervention, rather than supportive care alone, may benefit some victims of severe chest trauma.

Objective: To determine properties of acadesine, the prototype adenosine regulating agent, in an experimental model in which abdominal sepsis is superimposed onto hemorrhagic shock., Design: Randomized, blinded animal study., Setting: University-based animal research facility., Subjects: Twenty-eight anesthetized mongrel pigs (35.5 +/- 1.1 kg)., Interventions: The cecum was ligated and punctured to produce abdominal sepsis. To produce hemorrhagic shock, 45% to 47% of the estimated blood volume was withdrawn. After 1 hr, shed blood plus supplemental crystalloid (twice the shed blood volume) plus either acadesine (5 mg/kg bolus + 1 mg/kg x 60 min, n = 10) or its vehicle (n = 10) was administered. All animals were awakened and observed for 48 hrs. At 48 hrs, cardiac function, bacterial cultures from the septic focus, and inflammatory changes in the abdomen were quantified., Measurements and Main Results: After resuscitation with acadesine vs. vehicle, we observed the following: a) arterial blood pressure and cardiac filling pressures were similar but cardiac index, systemic oxygen delivery, and systemic oxygen consumption were increased; b) plasma lactate was higher, systemic vascular resistance was lower, but ileal mucosal blood flow was not measurably altered; c) lipopolysaccharide-evoked tumor necrosis factor production in whole blood ex vivo was reduced; d) in those animals that survived 48 hrs (10/10 vs. 8/10), sepsis-induced cardiac depression, amount of free intraperitoneal fluid, extra abscess inflammatory reaction, abscess wall formation, abscess bacterial counts, and peritoneal bacterial counts, were all similar, but blood bacterial counts were higher., Conclusions: Fluid resuscitation with acadesine produced no adverse hemodynamic consequences and probably improved washout of metabolites from the reperfused microcirculation in sites other than the small intestine or heart. Taken together, these observations suggest that adenosine regulating agents might have therapeutic potential during fluid resuscitation from trauma. However, at least in these extreme conditions, the acute salutary effects of acadesine were probably overwhelmed by polymicrobial sepsis. Further studies must determine whether supplemental adjuvants to boost host defense during recovery from trauma will optimize adenosine-based resuscitation solutions.

Objective: To determine whether blood lactate, base deficit, or oxygen-derived hemodynamic variables correlate with morbidity and mortality rates in a clinically-relevant LD50 model of penetrating trauma., Design: Prospective, controlled study., Setting: University research laboratory., Subjects: Anesthetized, mechanically-ventilated mongrel pigs (30+/-2 kg, n = 29)., Interventions: A captive bolt gun delivered a penetrating injury to the thigh, followed immediately by a 40% to 60% hemorrhage. After 1 hr, shed blood and supplemental crystalloid were administered for resuscitation., Measurements and Main Results: After penetrating injury, 50.7+/-0.3% hemorrhage (range 50% to 52.5%), and a 1-hr shock period, seven of 14 animals died, compared with six of six animals after 55% to 60% hemorrhage, and 0 of nine animals after < or =47.5% hemorrhage. Only two of 13 deaths occurred during fluid resuscitation. At the LD50 hemorrhage, peak lactate concentration and base deficit were 11.2+/-0.8 mM and 9.3+/-1.5 mmol/L, respectively, and minimum mixed venous oxygen saturation, systemic oxygen delivery, and systemic oxygen consumption were 33+/-5%, 380+/-83 mL/min/kg, and 177+/-35 mL/min/kg, respectively. For comparison, baseline preinjury values were 1.6+/-0.1 mM, -6.7+/-0.6 mmol/L, 71+/-3%, 2189+/-198 mL/min/kg, and 628+/-102 mL/min/kg, respectively. Of all the variables, only lactate was significantly related to blood loss before and after fluid resuscitation in the 16 survivors. However, r2 values were relatively low (.20 to .50), which indicates that only a small fraction of the hyperiactacidemia was directly related to tissue hypoperfusion. In the whole population of survivors and nonsurvivors, both lactate and base deficit (but none of the oxygen-derived variables) correlated with blood loss., Conclusions: Arterial lactate is a stronger index of blood loss after penetrating trauma than base deficit or oxygen-derived hemodynamic variables. The reliability of arterial lactate depends on several factors, such as the time after injury, the proportion of survivors and nonsurvivors in the study population, and on factors other than tissue hypoxia.

Objective: There were two aims of this study. The first was to evaluate the application of helical computed tomography of the thorax (HCTT) for the diagnosis of blunt aortic injury (BAI). The second was to evaluate the efficacy of beta-blockers with or without nitroprusside in preventing aortic rupture., Summary Background Data: Aortography has been the standard for diagnosing BAI for the past 4 decades. Conventional chest CT has not proven to be of significant value. Helical CT scanning is faster and has higher resolution than conventional CT. Retrospective studies have suggested the efficacy of antihypertensives in preventing aortic rupture., Methods: A prospective study comparing HCTT to aortography in the diagnosis of BAI was performed. A protocol of beta-blockers with or without nitroprusside was also examined for efficacy in preventing rupture before aortic repair and in allowing delayed repair in patients with significant associated injuries., Results: Over a period of 4 years, 494 patients were studied. BAI was diagnosed in 71 patients. Sensitivity was 100% for HCTT versus 92% for aortography. Specificity was 83% for HCTT versus 99% for aortography. Accuracy was 86% for HCTT versus 97% for aortography. Positive predictive value was 50% for HCTT versus 97% for aortography. Negative predictive value was 100% for HCTT versus 97% for aortography. No patient had spontaneous rupture in this study., Conclusions: HCTT is sensitive for diagnosing intimal injuries and pseudoaneurysms. Patients without direct HCTT evidence of BAI require no further evaluation. Aortography can be reserved for indeterminate HCTT scans. Early diagnosis with HCTT and presumptive treatment with the antihypertensive regimen eliminated in-hospital aortic rupture.

Objective: This prospective trial examined the efficacy of using bronchoalveolar lavage (BAL) for the diagnosis of pneumonia (PN) and the utility of Gram's stain (GS) for dictating empiric therapy., Summary Background Data: Posttraumatic nosocomial PN remains a significant cause of morbidity and mortality. However, its diagnosis is elusive, especially in multiply injured patients. The systemic inflammatory response syndrome of fever, leukocytosis, and a hyperdynamic state is common in trauma patients, especially patients with pulmonary contusion. Bronchoscopy with BAL with quantitative cultures of the lavage effluent may distinguish between PN and systemic inflammatory response syndrome, and GS of the lavage effluent may guide empiric therapy before quantitative culture results., Methods: Mechanically ventilated trauma patients with a clinical diagnosis of PN (fever, leukocytosis, purulent sputum, and new or changing infiltrate on chest radiograph) underwent bronchoscopy with BAL. Effluent was sent for GS and quantitative cultures. The diagnostic threshold for PN was > or =10(5) colony-forming units (CFU)/mL, and antibiotics were continued. Antibiotics were stopped for < 10(5) CFU/mL and the diagnosis of systemic inflammatory response syndrome was made. Causative organisms for PN were compared to GS., Results: Over a 2-year period, 232 patients underwent 443 bronchoscopies with BAL (71% men, 29% women; mean age, 41). The mean injury severity score was 30. Sixty percent of the patients had pulmonary contusion, and 59% were cigarette smokers. The overall incidence of PN was 39% and was no different regardless of the number of BALs a patient had. The false-negative rate of BAL was 7%. GS identified gram-positive organisms in 80% of patients with gram-positive PN and 40% of patients with gram-negative PN. GS identified gram-negative organisms in 52% of patients with gram-positive PN and 77% with gram-negative PN. The duration of the intensive care unit stay relative to the timing of BAL was beneficial for guiding empiric therapy. BAL in week 1 primarily identified Haemophilus influenzae and gram-positive organisms; Acinetobacter sp. and Pseudomonas sp. were more common after week 1., Conclusions: Bronchoscopy with BAL is an effective method to diagnose PN and avoids prolonged, unnecessary antibiotic therapy. Empiric therapy should be adjusted to the duration of the intensive care unit stay because the causative bacteria flora changes over time. GS of BAL effluent correlates poorly with quantitative cultures and is not reliable for dictating empiric therapy.

Objective: This study was conducted to evaluate those factors associated with popliteal artery injury that influence amputation, with emphasis placed on those that the surgeon can control., Summary Background Data: Generally accepted factors impacting amputation after popliteal artery injury include blunt trauma, prolonged ischemic times, musculoskeletal injuries, and venous disruption. Amputation ultimately results from microvascular thrombosis and subsequent tissue necrosis, predisposed by the paucity of collaterals around the knee., Methods: Patients with popliteal artery injuries over the 10-year period ending November 1995 were identified from the trauma registry. Preoperative (demographics, mechanism and severity of injury, vascular examination, ischemic times) and operative (methods of arterial repair, venous repair-ligation, anticoagulation-thrombolytic therapy, fasciotomy) variables were studied. Severity of extremity injury was quantitated by the Mangled Extremity Severity Score (MESS). Amputations were classified as primary (no attempt at vascular repair) or secondary (after vascular repair). After univariate analysis, logistic regression analysis was performed to identify the independent risk factors for limb loss., Results: One hundred two patients were identified; 88 (86%) were males and 14 (14%) were females. Forty injuries resulted from blunt and 62 from penetrating trauma. There were 25 amputations (25%; 11 primary and 14 secondary). Patients with totally ischemic extremities (no palpable or Doppler pulse) more likely were to be amputated (31% vs. 13%; p < 0.04). All requiring primary amputations had severe soft tissue injury and three had posterior tibial nerve transection; the average MESS was 7.6. Logistic regression analysis identified independent factors associated with secondary amputation: blunt injury (p = 0.06), vein injury (p = 0.06), MESS (p = 0.0001), heparin-urokinase therapy (p = 0.05). There were no complications with either heparin or urokinase., Conclusions: Minimizing ischemia is an important factor in maximizing limb salvage. Severity of limb injury, as measured by the MESS, is highly predictive of amputation. Intraoperative use of systemic heparin or local urokinase or both was the only directly controllable factor associated with limb salvage. The authors recommend the use of these agents to maximize limb salvage in association with repair of popliteal artery injuries.

The biomechanical performance of polytetrafluoroethylene (PTFE) sutures has been compared with that of polypropylene sutures, the standard to which other sutures used in vascular and cardiac surgery are compared. The PTFE is supple and has no plastic memory, while the polypropylene suture is stiff and retains its plastic memory. In addition, the rate of creep encountered in the PTFE suture was significantly less than that of the polypropylene suture. The knotting profiles for knot security for either a square, granny, or surgeon's knot for polypropylene sutures were three throws each. In contrast, knot security with either a square or granny PTFE knot was accomplished with seven throws; six throws were needed for a secure surgeon's knot. The breaking strength of the unknotted and knotted PTFE sutures was approximately one half as great as that for the unknotted and knotted polypropylene sutures. Knot construction significantly reduced the breaking strength of polypropylene sutures but did not alter the breaking strength of PTFE sutures. The percent elongation experienced by both sutures before breakage did not differ significantly. The elasticity, as measured by work recovery, for the polypropylene suture was greater than that for the PTFE suture. On the basis of its unique biomechanical performance characteristics, the PTFE suture should have an important place in vascular and cardiac surgery.