Community of trauma care partnering with stakeholders to improve injury outcomes: focus group analysis

Introduction

Engaging trauma survivors/caregivers results in research findings that are more relevant to patients' needs and priorities. Although their perspectives increase research significance, there is a lack of understanding about how best to incorporate their insights. We aimed to capture stakeholder perspectives to ensure research is meaningful, respectful, and relevant to the injured patient and their caregivers.

Methods

A multiphase, inductive exploratory qualitative study was performed, the first phase of which is described here. Virtual focus groups to elicit stakeholder perspectives and preferences were conducted across 19 trauma centers in the USA during 2022. Discussion topics were chosen to identify patients' motivation to join research studies, preferences regarding consent, suggestions for increasing diversity and access, and feelings regarding outcomes, efficacy, and exception from informed consent. The focus groups were audio recorded, transcribed, coded, and analyzed to identify the range of perspectives expressed and any common themes that emerged.

Results

Ten 90-minute focus groups included patients/caregiver (n=21/1) and researchers (n=14). Data analysis identified common themes emerging across groups. The importance of trust and preexisting relationships with the clinical care team were the most common themes across all groups.

Conclusion

Our findings reveal common themes in preferences, motivations, and best practices to increase patient/caregiver participation in trauma research. The project's next phases are distribution of a vignette-based survey to establish broad stakeholder consensus; education and dissemination activities to share strategies that increase research engagement and relevance for patients; and the formation of a panel of patients to support future research endeavors.

Level of evidence

Level IV.

Circular RNA Cdr1as inhibits proliferation and delays injury-induced regeneration of the intestinal epithelium

Circular RNAs (circRNAs) are highly expressed in the mammalian intestinal epithelium, but their functions remain largely unknown. Here, we identified the circRNA Cdr1as as a repressor of intestinal epithelial regeneration and defense. Cdr1as levels increased in mouse intestinal mucosa after colitis and septic stress, as well as in human intestinal mucosa from patients with inflammatory bowel disease and sepsis. Ablation of the Cdr1as locus from the mouse genome enhanced renewal of the intestinal mucosa, promoted injury-induced epithelial regeneration, and protected the mucosa against colitis. We found approximately 40 microRNAs, including miR-195, differentially expressed between intestinal mucosa of Cdr1as-knockout (Cdr1as-/-) versus littermate mice. Increasing the levels of Cdr1as inhibited intestinal epithelial repair after wounding in cultured cells and repressed growth of intestinal organoids cultured ex vivo, but this inhibition was abolished by miR-195 silencing. The reduction in miR-195 levels in the Cdr1as-/- intestinal epithelium was the result of reduced stability and processing of the precursor miR-195. These findings indicate that Cdr1as reduces proliferation and repair of the intestinal epithelium at least in part via interaction with miR-195 and highlight a role for induced Cdr1as in the pathogenesis of unhealed wounds and disrupted renewal of the intestinal mucosa.

Extracellular RNA Sensing Mediates Inflammation and Organ Injury in a Murine Model of Polytrauma

Severe traumatic injury leads to marked systemic inflammation and multiorgan injury. Endogenous drivers such as extracellular nucleic acid may play a role in mediating innate immune response and the downstream pathogenesis. Here, we explored the role of plasma extracellular RNA (exRNA) and its sensing mechanism in inflammation and organ injury in a murine model of polytrauma. We found that severe polytrauma-bone fracture, muscle crush injury, and bowel ischemia-induced a marked increase in plasma exRNA, systemic inflammation, and multiorgan injury in mice. Plasma RNA profiling with RNA sequencing in mice and humans revealed a dominant presence of miRNAs and marked differential expression of numerous miRNAs after severe trauma. Plasma exRNA isolated from trauma mice induced a dose-dependent cytokine production in macrophages, which was almost abolished in TLR7-deficient cells but unchanged in TLR3-deficient cells. Moreover, RNase or specific miRNA inhibitors against the selected proinflammatory miRNAs (i.e., miR-7a-5p, miR-142, let-7j, miR-802, and miR-146a-5p) abolished or attenuated trauma plasma exRNA-induced cytokine production, respectively. Bioinformatic analyses of a group of miRNAs based on cytokine readouts revealed that high uridine abundance (>40%) is a reliable predictor in miRNA mimic-induced cytokine and complement production. Finally, compared with the wild-type, TLR7-knockout mice had attenuated plasma cytokine storm and reduced lung and hepatic injury after polytrauma. These data suggest that endogenous plasma exRNA of severely injured mice and ex-miRNAs with high uridine abundance prove to be highly proinflammatory. TLR7 sensing of plasma exRNA and ex-miRNAs activates innate immune responses and plays a role in inflammation and organ injury after trauma.

EMERGING ROLE OF EXTRACELLULAR RNA IN INNATE IMMUNITY, SEPSIS, AND TRAUMA

ABSTRACT

Sepsis and trauma remain the leading causes of morbidity and mortality. Our understanding of the molecular pathogenesis in the development of multiple organ dysfunction in sepsis and trauma has evolved as more focus is on secondary injury from innate immunity, inflammation, and the potential role of endogenous danger molecules. Studies of the past several decades have generated evidence for extracellular RNAs (exRNAs) as biologically active mediators in health and disease. Here, we review studies on plasma exRNA profiling in mice and humans with sepsis and trauma, the role and mode of action by exRNAs, such as ex-micro(mi)RNAs, in host innate immune response, and their potential implications in various organ injury during sepsis and trauma.

Raising the bar on fibrinogen: a retrospective assessment of critical hypofibrinogenemia in severely injured trauma patients

Objectives

Fibrinogen depletion may occur at higher levels than historically referenced. We evaluated hypofibrinogenemia and associated mortality and multiple organ failure (MOF) after severe injury.

Methods

Retrospective investigation including 417 adult patients with Injury Severity Score (ISS) >15. Demographics and injury characteristics were collected. Fibrinogen within 30 minutes of admission was described: <150 mg/dL, 150 mg/dL to 200 mg/dL and >200 mg/dL. Primary outcome: 28-day mortality. Secondary outcomes: 28-day MOF and blood product transfusion. Multivariable logistic regression model evaluated association of fibrinogen categories on risk of death, after controlling for confounding variables. Results presented as OR and 95% CIs.

Results

Fibrinogen <150 mg/dL: 4.8%, 150 mg/dL to 200 mg/dL: 18.2%, >200 mg/dL: 77.0%. 28-day mortality: 15.6%. Patients with <150 mg/dL fibrinogen had over fourfold increased 28-day mortality risk (OR: 4.9, 95% CI 1.53 to 15.7) after adjusting for age, ISS and admission Glasgow Coma Scale. Patients with lower fibrinogen were more likely to develop MOF (p=0.04) and receive larger red blood cell transfusion volumes at 3 hours and 24 hours (p<0.01).

Conclusions

Fibrinogen <150 mg/dL is significantly associated with increased 28-day mortality. Patients with fibrinogen <150 mg/dL were more likely to develop MOF and required increased administration of blood products. The optimal threshold for critically low fibrinogen, the association with MOF and subsequent fibrinogen replacement requires further investigation.

Level of evidence

Level III.

Traumatic Brain Injury and Risk of Long-Term Nursing Home Entry among Older Adults: An Analysis of Medicare Administrative Claims Data

Traumatic brain injury (TBI) is a leading cause of injury-related disability among older adults, and there is increasing interest in post-discharge management as this population grows. We evaluated the association between TBI and long-term nursing home (NH) entry among a nationally representative sample of older adults. We identified 207,355 adults aged ≥65 years who received a diagnosis of either a TBI, non-TBI trauma, or were uninjured between January 2008 and June 2015 from a 5% sample of Medicare beneficiaries. The NH entry was operationalized as the first NH admission that resulted in a stay ≥100 days. Time to NH entry was calculated as the difference between the NH entry date and the index date (the date of TBI, non-TBI trauma, or inpatient/outpatient visit in the uninjured group). We used cause-specific Cox proportional hazards models with stabilized inverse probability of exposure weights to model time to NH entry as a function of injury in the presence of death as a competing risk and generated hazard ratios (HR) and 95% confidence intervals (CI). After excluding beneficiaries living in a NH at index, there were 60,600 TBI, 63,762 non-TBI trauma, and 69,893 uninjured beneficiaries in the sample. In weighted models, beneficiaries with TBI entered NHs at higher rates relative to the non-TBI trauma (HR 1.15; 95% CI 1.10, 1.20) and uninjured (HR 1.67; 95% CI 1.60, 1.74) groups. Future research should focus on interventions to retain older adult TBI survivors within the community.

Lyophilized plasma resuscitation downregulates inflammatory gene expression in a mouse model of sepsis

BACKGROUND

Plasma resuscitation may improve outcomes by targeting endotheliopathy induced by severe sepsis or septic shock. Given the logistical constraints of using fresh frozen plasma in military settings or areas with prolonged prehospital care, dried products such as lyophilized plasma (LP) have been developed. We hypothesized that resuscitation with LP would decrease lung injury, inflammation, and mortality in a mouse sepsis model.

METHODS

Adult male C57BL/6J mice received an intraperitoneal injection of cecal slurry. Twenty-two hours later, the mice were anesthetized, the femoral artery was cannulated, and the mice were randomized to receive resuscitation with LP (10 mL/kg) or lactated Ringer's (LR; 30 mL/kg) for 1 hour. At 48-hours post-cecal slurry injection, bronchoalveolar lavage fluid was collected, the lungs were harvested, and plasma was obtained. Mortality and bronchoalveolar lavage total protein concentration (as an indicator of permeability) were compared between groups. The lungs were analyzed for histopathology and inflammatory gene expression using NanoString, and the plasma was analyzed for biomarkers of inflammation and endothelial function.

RESULTS

There was no significant difference in short-term mortality between LR and LP mice, 38% versus 47%, respectively ( p = 0.62). Bronchoalveolar lavage protein levels were similar among mice resuscitated with LR or LP, and there was a lack of significant histopathologic lung injury in all groups. However, LP resuscitation resulted in downregulation of pulmonary inflammatory genes, including signaling pathways such as Janus kinase-signal transducer and activator of transcription and nuclear factor κB, and a circulating inflammatory biomarker profile similar to sham animals.

CONCLUSION

Resuscitation with LP did not improve mortality or reduce permeability or injury in this model compared with LR. However, LP downregulated pulmonary inflammatory gene signaling and may also reduce circulating biomarkers of inflammation. Future studies should evaluate LP resuscitation in combination with antibiotics and other therapeutics to determine whether the anti-inflammatory effects of LP may improve outcomes in sepsis.

Multi-center validation of the Bowel Injury Predictive Score (BIPS) for the early identification of need to operate in blunt bowel and mesenteric injuries

INTRODUCTION

The Bowel Injury Prediction Score (BIPS) is a tool for identifying patients at risk for blunt bowel and mesenteric injury (BBMI) requiring surgery. BIPS is calculated by assigning one point for each of the following: (1) WBC ≥ 17,000, (2) abdominal tenderness, and (3) injury grade ≥ 4 (mesenteric contusion or hematoma with bowel wall thickening or adjacent interloop fluid collection) on CT scan. A total score ≥ 2 is associated with BBMI requiring surgery. We aimed to validate the BIPS as a predictor for patients with BBMIs requiring operative intervention in a multi-center prospective study.

MATERIALS AND METHODS

Patients were prospectively enrolled at 15 U.S. trauma centers following blunt trauma with suspicion of BBMI on CT scan between July 1, 2018 and July 31, 2019. The BIPS was calculated for each patient enrolled in the study.

RESULTS

Of 313 patients, 38% had BBMI requiring operative intervention. Patients were significantly more likely to require surgery in the presence of abdominal tenderness (OR, 3.6; 95% CI, 1.6-8.0) and CT grade ≥ 4 (OR, 11.7; 95% CI, 5.7-23.7). Patients with a BIPS ≥ 2 were more than ten times more likely to require laparotomy than those with a BIPS < 2 (OR, 10.1; 95% CI, 5.0-20.4). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a BIPS ≥ 2 for BBMI requiring surgery was 72% (CI 0.6-0.8), 78% (CI 0.7-0.8), 67% (CI 0.6-0.8), and 82% (CI 0.8-0.9), respectively. The AUROC curve for BIPS ≥ 2 was 0.75. The sensitivity, specificity, PPV, and NPV of a BIPS ≥ 2 for BBMI requiring surgery in patients with severe alteration in mental status (GCS 3-8) was 70% (CI 0.5-0.9), 92% (CI 0.8-1.0), 82% (CI 0.6-1.0), and 86% (CI 0.7-1.0), respectively.

CONCLUSION

This prospective multi-center trial validates BIPS as a predictor of BBMI requiring surgery. Calculation of BIPS during the initial evaluation of trauma patients is a useful adjunct to help general surgeons taking trauma call determine operative versus non-operative management of patients with BBMI including those with severe alteration in mental status.

Role of extracellular microRNA-146a-5p in host innate immunity and bacterial sepsis

Extracellular miRNAs (ex-miRNAs) mediate intercellular communication and play a role in diverse physiological and pathological processes. Using small RNA sequencing, we identify that miRNAs are the most abundant RNA species in the plasma and differentially expressed in murine and human sepsis, such as miR-146a-5p. Exogenous miR-146a-5p, but not its duplex precursor, induces a strong immunostimulatory response through a newly identified UU-containing motif and TLR7 activation, and an immunotolerance by rapid IRAK-1 protein degradation via TLR7→MyD88 signaling and proteasome activation, whereas its duplex precursor acts by targeting 3' UTR of Irak-1 gene via Ago2 binding. miR-146a knockout in mice offers protection against sepsis with attenuated interleukin-6 (IL-6) storm and organ injury, improved cardiac function, and better survival. In septic patients, the plasma miR-146a-5p concentrations are closely associated with the two sepsis outcome predictors, blood lactate and coagulopathy. These data demonstrate the importance of extracellular miR-146a-5p in innate immune regulation and sepsis pathogenesis.

Air-Evacuation-Relevant Hypobaria Following Traumatic Brain Injury Plus Hemorrhagic Shock in Rats Increases Mortality and Injury to the Gut, Lungs, and Kidneys

ABSTRACT

Rats exposed to hypobaria equivalent to what occurs during aeromedical evacuation within a few days after isolated traumatic brain injury exhibit greater neurologic injury than those remaining at sea level. Moreover, administration of excessive supplemental O2 during hypobaria further exacerbates brain injury. This study tested the hypothesis that exposure of rats to hypobaria following controlled cortical impact (CCI)-induced brain injury plus mild hemorrhagic shock worsens multiple organ inflammation and associated mortality. In this study, at 24 h after CCI plus hemorrhagic shock, rats were exposed to either normobaria (sea level) or hypobaria (=8,000 ft altitude) for 6 h under normoxic or hyperoxic conditions. Injured rats exhibited mortality ranging from 30% for those maintained under normobaria and normoxia to 60% for those exposed to 6 h under hypobaric and hyperoxia. Lung histopathology and neutrophil infiltration at 2 days postinjury were exacerbated by hypobaria and hyperoxia. Gut and kidney inflammation at 30 days postinjury were also worsened by hypobaric hyperoxia. In conclusion, exposure of rats after brain injury and hemorrhagic shock to hypobaria or hyperoxia results in increased mortality. Based on gut, lung, and kidney histopathology at 2 to 30 days postinjury, increased mortality is consistent with multi-organ inflammation. These findings support epidemiological studies indicating that increasing aircraft cabin pressures to 4,000 ft altitude (compared with standard 8,000 ft) and limiting excessive oxygen administration will decrease critical complications during and following aeromedical transport.

Circular RNA CircHIPK3 Promotes Homeostasis of the Intestinal Epithelium by Reducing MicroRNA 29b Function

BACKGROUND & AIMS

Circular RNAs (circRNAs) are a class of endogenous noncoding RNAs that form covalently closed circles. Although circRNAs influence many biological processes, little is known about their role in intestinal epithelium homeostasis. We surveyed circRNAs required to maintain intestinal epithelial integrity and identified circular homeodomain-interacting protein kinase 3 (circHIPK3) as a major regulator of intestinal epithelial repair after acute injury.

METHODS

Intestinal mucosal tissues were collected from mice exposed to cecal ligation and puncture for 48 hours and patients with inflammatory bowel diseases and sepsis. We isolated primary enterocytes from the small intestine of mice and derived intestinal organoids. The levels of circHIPK3 were silenced in intestinal epithelial cells (IECs) by transfection with small interfering RNAs targeting the circularization junction of circHIPK3 or elevated using a plasmid vector that overexpressed circHIPK3. Intestinal epithelial repair was examined in an in vitro injury model by removing part of the monolayer. The association of circHIPK3 with microRNA 29b (miR-29b) was determined by biotinylated RNA pull-down assays.

RESULTS

Genome-wide profile analyses identified ∼300 circRNAs, including circHIPK3, differentially expressed in the intestinal mucosa of mice after cecal ligation and puncture relative to sham mice. Intestinal mucosa from patients with inflammatory bowel diseases and sepsis had reduced levels of circHIPK3. Increasing the levels of circHIPK3 enhanced intestinal epithelium repair after wounding, whereas circHIPK3 silencing repressed epithelial recovery. CircHIPK3 silencing also inhibited growth of IECs and intestinal organoids, and circHIPK3 overexpression promoted intestinal epithelium renewal in mice. Mechanistic studies revealed that circHIPK3 directly bound to miR-29b and inhibited miR-29 activity, thus increasing expression of Rac1, Cdc42, and cyclin B1 in IECs after wounding.

CONCLUSIONS

In studies of mice, IECs, and human tissues, our results indicate that circHIPK3 improves repair of the intestinal epithelium at least in part by reducing miR-29b availability.

Hypobaria Exposure Worsens Cardiac Function and Endothelial Injury in AN Animal Model of Polytrauma: Implications for Aeromedical Evacuation

BACKGROUND

Aeromedical evacuation can expose traumatically injured patients to low pressure (hypobaria) and hypoxia. Here, we sought to assess the impact of hypobaria on inflammation, organ injury, and mortality in a mouse model of polytrauma.

METHODS

Eight to 12-week-old male C57BL/6J mice were subjected to sham or polytrauma consisting of bowel ischemia by superior mesenteric artery occlusion, hindlimb muscle crush, and tibia fracture. Two hours after injury, animals were randomized to undergo either 6 h of hypobaria or sea-level, room air conditions. At 8 or 24 h after injury, transthoracic echocardiography was performed. Acute kidney injury (AKI) biomarkers were measured by qRT-PCR. Plasma cytokine and endothelial injury markers were determined by enzyme-linked immunosorbent assay.

RESULTS

Eight hours after traumatic injury, mice exhibited a marked increase in plasma IL-6 (57 pg/mL vs. 1,216 pg/mL), AKI with increased Ngal and Kim-1, and endothelial injury as evidenced by significantly increased plasma hyaluronic acid (96 ng/mL vs.199 ng/mL), thrombomodulin (23.2 ng/mL vs. 58.9 ng/mL), syndecan-1 (0.99 ng/mL vs. 4.34 ng/mL), and E-selectin (38.6 ng/mL vs. 62.7 ng/mL). The trauma mice also developed cardiac dysfunction with decreased cardiac output and stroke volume at 8 h postinjury. Hypobaric exposure after polytrauma led to decreased ejection fraction (81.0% vs. 74.2%, P < 0.01) and increased plasma hyaluronic acid (199 ng/mL vs. 260 ng/mL, P < 0.05), thrombomodulin (58.9 ng/mL vs. 75.4 ng/mL, P < 0.05), and syndecan-1 (4.34 ng/mL vs. 8.33 ng/mL, P < 0.001) at 8 h postinjury.

CONCLUSIONS

Hypobaria exposure appeared to worsen cardiac dysfunction and endothelial injury following polytrauma and thus may represent a physiological "second hit" following traumatic injury.

Cryoprecipitate attenuates the endotheliopathy of trauma in mice subjected to hemorrhagic shock and trauma

BACKGROUND

Plasma has been shown to mitigate the endotheliopathy of trauma. Protection of the endothelium may be due in part to fibrinogen and other plasma-derived proteins found in cryoprecipitate; however, the exact mechanisms remain unknown. Clinical trials are underway investigating early cryoprecipitate administration in trauma. In this study, we hypothesize that cryoprecipitate will inhibit endothelial cell (EC) permeability in vitro and will replicate the ability of plasma to attenuate pulmonary vascular permeability and inflammation induced by hemorrhagic shock and trauma (HS/T) in mice.

METHODS

In vitro, barrier permeability of ECs subjected to thrombin challenge was measured by transendothelial electrical resistance. In vivo, using an established mouse model of HS/T, we compared pulmonary vascular permeability among mice resuscitated with (1) lactated Ringer's solution (LR), (2) fresh frozen plasma (FFP), or (3) cryoprecipitate. Lung tissue from the mice in all groups was analyzed for markers of vascular integrity, inflammation, and inflammatory gene expression via NanoString messenger RNA quantification.

RESULTS

Cryoprecipitate attenuates EC permeability and EC junctional compromise induced by thrombin in vitro in a dose-dependent fashion. In vivo, resuscitation of HS/T mice with either FFP or cryoprecipitate attenuates pulmonary vascular permeability (sham, 297 ± 155; LR, 848 ± 331; FFP, 379 ± 275; cryoprecipitate, 405 ± 207; p < 0.01, sham vs. LR; p < 0.01, LR vs. FFP; and p < 0.05, LR vs. cryoprecipitate). Lungs from cryoprecipitate- and FFP-treated mice demonstrate decreased lung injury, decreased infiltration of neutrophils and activation of macrophages, and preserved pericyte-endothelial interaction compared with LR-treated mice. Gene analysis of lung tissue from cryoprecipitate- and FFP-treated mice demonstrates decreased inflammatory gene expression, in particular, IL-1β and NLRP3, compared with LR-treated mice.

CONCLUSION

Our data suggest that cryoprecipitate attenuates the endotheliopathy of trauma in HS/T similar to FFP. Further investigation is warranted on active components and their mechanisms of action.

Quantification of von Willebrand factor and ADAMTS-13 after traumatic injury: a pilot study

BACKGROUND

Von Willebrand factor (VWF) is an acute phase reactant synthesized in the megakaryocytes and endothelial cells. VWF forms ultra-large multimers (ULVWF) which are cleaved by the metalloprotease ADAMTS-13, preventing spontaneous VWF-platelet interaction. After trauma, ULVWF is released into circulation as part of the acute phase reaction. We hypothesized that trauma patients would have increased levels of VWF and decreased levels of ADAMTS-13 and that these patients would have accelerated thrombin generation.

METHODS

We assessed plasma concentrations of VWF antigen and ADAMTS-13 antigen, the Rapid Enzyme Assays for Autoimmune Diseases (REAADS) activity of VWF, which measure exposure of the platelet-binding A1 domain, and thrombin generation kinetics in 50 samples from 30 trauma patients and an additional 21 samples from volunteers. Samples were analyzed at 0 to 2 hours and at 6 hours from the time of injury. Data are presented as median (IQR) and Kruskal-Wallis test was performed between trauma patients and volunteers at both time points.

RESULTS

REAADS activity was greater in trauma patients than volunteers both at 0 to 2 hours (190.0 (132.0-264.0) vs. 92.0 (71.0-114.0), p<0.002) and at 6 hours (167.5 (108.0-312.5.0) vs. 92.0 (71.0-114.0), p<0.001). ADAMTS-13 antigen levels were also decreased in trauma patients both at 0 to 2 hours (0.84 (0.51-0.94) vs. 1.00 (0.89-1.09), p=0.010) and at 6 hours (0.653 (0.531-0.821) vs. 1.00 (0.89-1.09), p<0.001). Trauma patients had accelerated thrombin generation kinetics, with greater peak height and shorter time to peak than healthy volunteers at both time points.

DISCUSSION

Trauma patients have increased exposure of the VWF A1 domain and decreased levels of ADAMTS-13 compared with healthy volunteers. This suggests that the VWF burst after trauma may exceed the proteolytic capacity of ADAMTS-13, allowing circulating ULVWF multimers to bind platelets, potentially contributing to trauma-induced coagulopathy.

LEVEL OF EVIDENCE

Prospective case cohort study.

Freeze-dried platelets promote clot formation, attenuate endothelial cell permeability, and decrease pulmonary vascular leak in a murine model of hemorrhagic shock

BACKGROUND

Hemorrhagic shock (HS) and trauma induce endothelial barrier compromise, inflammation, and aberrant clotting. We have shown that fresh human platelets (Plts) and Plt extracellular vesicles mitigate vascular leak in murine models of injury. Here, we investigate the potential of freeze-dried platelets (FDPlts) to attenuate pulmonary vascular permeability, decrease inflammation, and promote clotting in a murine model of HS.

METHODS

Human FDPlts were characterized using in vitro assays of Plt marker expression, aggregation, coagulation, and endothelial cell permeability. An intravital model of vascular injury in the mouse cremaster muscle was used to assess the ability of FDPlts to incorporate into clots. Mouse groups subjected to controlled hemorrhage for 90 minutes were (1) lactated Ringer solution (LR), (2) FDPlts, (3) fresh human Plts, (4) murine whole blood (WB), and (5) shams (only instrumented). Hemorrhagic shock mouse endpoints included coagulation, pulmonary vascular permeability, and lung injury.

RESULTS

Freeze-dried Plts expressed Plt-specific markers and retained functionality similar to fresh Plts. In in vitro assays of Plt aggregation, differences were noted. In vivo, FDPlts and Plts were found to incorporate into clots in postcapillary venules in the mouse cremaster muscle. Hemorrhagic shock mice resuscitated with LR displayed increased pulmonary vascular permeability compared with sham (sham, 686.6 ± 359.7; shock-LR, 2,637 ± 954.7; p = 0.001), and treatment with FDPlts or WB attenuated permeability compared with shock: shock-FDPlts, 1,328 ± 462.6 (p = 0.05), and shock-WB, 1,024 ± 370.5 (p = 0.0108). However, human Plts (Days 1-3) did not attenuate vascular leak in HS mice compared with shock-LR (shock-Plts, 3,601 ± 1,581; p = 0.33).

CONCLUSION

FDPlts contribute to clot formation similar to fresh human Plts. FDPlts also attenuated vascular permeability in vitro and in vivo. Mouse WB resuscitation but not fresh human Plts attenuated vascular permeability after HS. These data suggest that the effect of FDPlts may be a suitable alternative to fresh Plts in modulating hemostasis and the endotheliopathy associated with injury.

Diverse activities of von Willebrand factor in traumatic brain injury and associated coagulopathy

Traumatic brain injury (TBI) is a leading cause of death and disability. Patients with isolated TBI lose a limited amount of blood to primary injury, but they often develop secondary coagulopathy, resulting in delayed or recurrent intracranial and intracerebral hematoma. TBI-induced coagulopathy is closely associated with poor outcomes for these patients, including death. This secondary coagulopathy is consumptive in nature, involving not only brain-derived molecules, coagulation factors, and platelets, but also endothelial cells in a complex process now called blood failture. A key question is how a localized injury to the brain is rapidly disseminated to affect systemic hemostasis that is not directly affected the way it is in trauma to the body and limbs, especially with hemorrhagic shock. Increasing evidence suggests that the adhesive ligand von Willebrand factor (VWF), which is synthesized in and released from endothelial cells, plays a paradoxical role in both facilitating local hemostasis at the site of injury and also propagating TBI-induced endotheliopathy and coagulopathy systemically. This review discusses recent progress in understanding these diverse activities of VWF and the knowledge gaps in defining their roles in TBI and associated coagulopathy.

Age is a predictor for mortality after blunt splenic injury

BACKGROUND

While the incidence of geriatric trauma continues to increase, the management of high-grade blunt splenic injury (BSI) in the elderly remains controversial. Among this population, data evaluating survival rates following non-operative and operative management are inconsistent. We analyzed mortality risk in geriatric patients with high-grade BSI based on operative vs. non-operative management.

METHODS

A retrospective analysis of the National Trauma Database identified patients with isolated, high-grade (AIS ≥ 3) BSI from 2014 to 2015. Patients were stratified into three groups: non-elderly (<65 years), elderly (65-79 years), and advanced age (80 years and older). Each age group was stratified into three management groups: non-operative (including embolization), initial operative management (OR within 24 h), and failed non-operative management. Patient characteristics and outcomes were compared. Multivariable logistic regression estimated association with mortality.

RESULTS

5560 patients with isolated, high-grade BSI were identified. In the group that failed NOM, mortality was 2% in non-elderly patients, versus 22.2% in elderly patients and 50% in patients of advanced age (p < .01). In this group, patients over 80 years old spent an average of 6.5 days longer in the ICU vs. non-elderly patients (median 10.5 days, IQR [6.75, 19.5] vs. 4 days, IQR [3,6], p = 0.02). In patients with isolated, high grade BSI, age was independently associated with mortality (AOR 1.02; p < 0.01). Elderly patients who required surgery were over three times more likely to die (AOR 3.39; p < 0.01). Advanced age patients who required surgery were over eight times more likely to die (AOR 8.1; p < 0.01).

CONCLUSIONS

For patients with BSI, age is independently associated with death in both operative and non-operative cases.

American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on Nutrition Screening and Therapy Within a Surgical Enhanced Recovery Pathway

Perioperative malnutrition has proven to be challenging to define, diagnose, and treat. Despite these challenges, it is well known that suboptimal nutritional status is a strong independent predictor of poor postoperative outcomes. Although perioperative caregivers consistently express recognition of the importance of nutrition screening and optimization in the perioperative period, implementation of evidence-based perioperative nutrition guidelines and pathways in the United States has been quite limited and needs to be addressed in surgery-focused recommendations. The second Perioperative Quality Initiative brought together a group of international experts with the objective of providing consensus recommendations on this important topic with the goal of (1) developing guidelines for screening of nutritional status to identify patients at risk for adverse outcomes due to malnutrition; (2) address optimal methods of providing nutritional support and optimizing nutrition status preoperatively; and (3) identifying when and how to optimize nutrition delivery in the postoperative period. Discussion led to strong recommendations for implementation of routine preoperative nutrition screening to identify patients in need of preoperative nutrition optimization. Postoperatively, nutrition delivery should be restarted immediately after surgery. The key role of oral nutrition supplements, enteral nutrition, and parenteral nutrition (implemented in that order) in most perioperative patients was advocated for with protein delivery being more important than total calorie delivery. Finally, the role of often-inadequate nutrition intake in the posthospital setting was discussed, and the role of postdischarge oral nutrition supplements was emphasized.

American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on Patient-Reported Outcomes in an Enhanced Recovery Pathway

Patient-reported outcomes (PROs) are measures of health status that come directly from the patient. PROs are an underutilized tool in the perioperative setting. Enhanced recovery pathways (ERPs) have primarily focused on traditional measures of health care quality such as complications and hospital length of stay. These measures do not capture postdischarge outcomes that are meaningful to patients such as function or freedom from disability. PROs can be used to facilitate shared decisions between patients and providers before surgery and establish benchmark recovery goals after surgery. PROs can also be utilized in quality improvement initiatives and clinical research studies. An expert panel, the Perioperative Quality Initiative (POQI) workgroup, conducted an extensive literature review to determine best practices for the incorporation of PROs in an ERP. This international group of experienced clinicians from North America and Europe met at Stony Brook, NY, on December 2-3, 2016, to review the evidence supporting the use of PROs in the context of surgical recovery. A modified Delphi method was used to capture the collective expertise of a diverse group to answer clinical questions. During 3 plenary sessions, the POQI PRO subgroup presented clinical questions based on a literature review, presented evidenced-based answers to those questions, and developed recommendations which represented a consensus opinion regarding the use of PROs in the context of an ERP. The POQI workgroup identified key criteria to evaluate patient-reported outcome measures (PROMs) for their incorporation in an ERP. The POQI workgroup agreed on the following recommendations: (1) PROMs in the perioperative setting should be collected in the framework of physical, mental, and social domains. (2) These data should be collected preoperatively at baseline, during the immediate postoperative time period, and after hospital discharge. (3) In the immediate postoperative setting, we recommend using the Quality of Recovery-15 score. After discharge at 30 and 90 days, we recommend the use of the World Health Organization Disability Assessment Scale 2.0, or a tailored use of the Patient-Reported Outcomes Measurement Information System. (4) Future study that consistently applies PROMs in an ERP will define the role these measures will have evaluating quality and guiding clinical care. Consensus guidelines regarding the incorporation of PRO measures in an ERP were created by the POQI workgroup. The inclusion of PROMs with traditional measures of health care quality after surgery provides an opportunity to improve clinical care.

Transitions of Care in Geriatric Medicine

Elderly patients are at increased risk for morbidity and mortality after injury or surgery in both the inpatient and postdischarge settings. The importance of discharge destination after the index hospitalization is increasingly recognized as a determinant of long-term survival, with discharge to a post-acute care facility portending a worse prognosis. Efforts to minimize discharge to post-acute care facilities should include early discharge planning. Communication among a multidisciplinary care team sets the groundwork for effective discharge planning and transitions of care. The elderly face several systematic, psychosocial, functional, and financial barriers that pose significant challenges to successful transitions of care.

Clinically Practical Approach for Screening of Low Muscularity Using Electronic Linear Measures on Computed Tomography Images in Critically Ill Patients

BACKGROUND

Computed tomography (CT) scans performed during routine hospital care offer the opportunity to quantify skeletal muscle and predict mortality and morbidity in intensive care unit (ICU) patients. Existing methods of muscle cross-sectional area (CSA) quantification require specialized software, training, and time commitment that may not be feasible in a clinical setting. In this article, we explore a new screening method to identify patients with low muscle mass.

METHODS

We analyzed 145 scans of elderly ICU patients (≥65 years old) using a combination of measures obtained with a digital ruler, commonly found on hospital radiological software. The psoas and paraspinal muscle groups at the level of the third lumbar vertebra (L3) were evaluated by using 2 linear measures each and compared with an established method of CT image analysis of total muscle CSA in the L3 region.

RESULTS

There was a strong association between linear measures of psoas and paraspinal muscle groups and total L3 muscle CSA (R² = 0.745, P < 0.001). Linear measures, age, and sex were included as covariates in a multiple logistic regression to predict those with low muscle mass; receiver operating characteristic (ROC) area under the curve (AUC) of the combined psoas and paraspinal linear index model was 0.920. Intraclass correlation coefficients (ICCs) were used to evaluate intrarater and interrater reliability, resulting in scores of 0.979 (95% CI: 0.940-0.992) and 0.937 (95% CI: 0.828-0.978), respectively.

CONCLUSIONS

A digital ruler can reliably predict L3 muscle CSA, and these linear measures may be used to identify critically ill patients with low muscularity who are at risk for worse clinical outcomes.

A randomized trial of supplemental parenteral nutrition in underweight and overweight critically ill patients: the TOP-UP pilot trial

Background

Nutrition guidelines recommendations differ on the use of parenteral nutrition (PN), and existing clinical trial data are inconclusive. Our recent observational data show that amounts of energy/protein received early in the intensive care unit (ICU) affect patient mortality, particularly for inadequate nutrition intake in patients with body mass indices (BMIs) of <25 or >35. Thus, we hypothesized increased nutrition delivery via supplemental PN (SPN) + enteral nutrition (EN) to underweight and obese ICU patients would improve 60-day survival and quality of life (QoL) versus usual care (EN alone).

Methods

In this multicenter, randomized, controlled pilot trial completed in 11 centers across four countries, adult ICU patients with acute respiratory failure expected to require mechanical ventilation for >72 hours and with a BMI of <25 or ≥35 were randomized to receive EN alone or SPN + EN to reach 100% of their prescribed nutrition goal for 7 days after randomization. The primary aim of this pilot trial was to achieve a 30% improvement in nutrition delivery.

Results

In total, 125 patients were enrolled. Over the first 7 post-randomization ICU days, patients in the SPN + EN arm had a 26% increase in delivered calories and protein, whereas patients in the EN-alone arm had a 22% increase (both p < 0.001). Surgical ICU patients received poorer EN nutrition delivery and had a significantly greater increase in calorie and protein delivery when receiving SPN versus medical ICU patients. SPN proved feasible to deliver with our prescribed protocol. In this pilot trial, no significant outcome differences were observed between groups, including no difference in infection risk. Potential, although statistically insignificant, trends of reduced hospital mortality and improved discharge functional outcomes and QoL outcomes in the SPN + EN group versus the EN-alone group were observed.

Conclusions

Provision of SPN + EN significantly increased calorie/protein delivery over the first week of ICU residence versus EN alone. This was achieved with no increased infection risk. Given feasibility and consistent encouraging trends in hospital mortality, QoL, and functional endpoints, a full-scale trial of SPN powered to assess these clinical outcome endpoints in high-nutritional-risk ICU patients is indicated—potentially focusing on the more poorly EN-fed surgical ICU setting.

Trial registration

NCT01206166

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1736-8) contains supplementary material, which is available to authorized users.

Gastric Feeding as an Extension of an Established Enteral Nutrition Protocol

BACKGROUND

Indiscriminate gastric feeding in ICU patients imposes unacceptable risks of aspiration. Believing that a subset of ICU patients can be fed safely via the stomach, we have developed a protocol to identify appropriate patients and guide the bedside clinician in how to safely and effectively feed via the stomach.

METHODS

A literature search was done to identify appropriate medical literature. High grade evidence along with local expert opinions were used to develop a protocol. This protocol has been refined and implemented.

RESULTS

Based on perceived risk of aspiration, patients are assigned enteral access (ie, stomach vs. distal post-pyloric). Enteral formula is selected based on patient characteristics. It is then advanced by a standard protocol with specific precautions while monitoring for symptoms of intolerance. Management of intolerance is dictated by the type and severity of intolerance.

CONCLUSION

We have implemented a gastric feeding into a subset of our ICU patients. Gastric feeding requires certain precautions but appears to be safe. With more experience and better understanding of the pathogenesis gastroparesis, we believe that most ICU patients should be able to safely feed into the stomach. This is logistically easier than post-pyloric feeding and offers physiologic advantages.

Validation of Bedside Ultrasound of Muscle Layer Thickness of the Quadriceps in the Critically Ill Patient (VALIDUM Study)

BACKGROUND

In critically ill patients, muscle atrophy is associated with long-term disability and mortality. Bedside ultrasound may quantify muscle mass, but it has not been validated in the intensive care unit (ICU). Here, we compared ultrasound-based quadriceps muscle layer thickness (QMLT) with precise quantifications of computed tomography (CT)-based muscle cross-sectional area (CSA).

METHODS

Patients ≥18 years old with abdominal CT scans performed for clinical reasons were recruited from 9 ICUs for an ultrasound assessment of the quadriceps. CT scans of the third lumbar vertebra, performed <24 hours before or <72 hours after ICU admission, were analyzed for CSA. Low muscularity was defined as 170 cm² for men and 110 cm² for women. The ultrasound probe was maximally compressed against the skin and QMLT was measured on 2 sites of each quadriceps <72 hours of the CT scan.

RESULTS

Mean CT-derived muscle CSA was 109 ± 25 cm² for women and 168 ± 37 cm² for men, where 58% of patients exhibited low muscularity; only 2.7% patients were underweight according to body mass index. QMLT was positively correlated with CT CSA ( r = 0.45, P < .001). Based on logistic regression to predict low muscularity, QMLT independently generated a concordance index ( c) of 0.67 ( P < .002), which increased to 0.77 ( P < .001) when age, sex, body mass index, Charlson Comorbidity Index, and admission type (surgical vs medical) were added.

CONCLUSIONS

Our results suggest that QMLT alone with our current protocol may not accurately identify patients with low muscle mass.

Microvesicle phenotypes are associated with transfusion requirements and mortality in subjects with severe injuries

BACKGROUND

Severe injury often results in substantial bleeding and mortality. Injury provokes cellular activation and release of extracellular vesicles. Circulating microvesicles (MVs) are predominantly platelet-derived and highly procoagulant. They support hemostasis and vascular function. The roles of MVs in survival after severe injury are largely unknown. We hypothesized that altered MV phenotypes would be associated with transfusion requirements and poor outcomes.

METHODS

This single-centre study was approved by the Institutional Review Board. The study cohort consisted of patients with major trauma requiring blood product transfusion and 26 healthy controls. Plasma samples for MVs were collected upon admission to the emergency department (n=169) and post-resuscitation (n=42), and analysed by flow cytometry for MV counts and cellular origin: platelet (PMV), erythrocyte (RMV), leukocyte (LMV), endothelial (EMV), tissue factor (TFMV), and annexin V (AVMV). Twenty-four hour mortality is the outcome measurement used to classify survivors versus non-survivors. Data were compared over time and analysed with demographic and clinical data.

RESULTS

The median age was 34 (IQR 23, 51), 72% were male, Injury Severity Score was 29 (IQR 19, 36), and 24 h mortality was 13%. MV levels and phenotypes differed between patients and controls. Elevated admission EMVs were found both in survivors (409/µL) and non-survivors (393/µL) compared to controls (23/µL, p<0.001) and persisted over time. Admission levels of PMV, AVMV, RMV, and TFMV were significantly lower in patients who died compared to survivors, but were not independently associated with the 24 h mortality rate. Patients with low MV levels at admission received the most blood products within the first 24 h. AVMV and PMV levels either increased over time or stabilized in survivors but decreased in non-survivors, resulting in significantly lower levels at intensive care unit admission in non-survivors (1,048 vs. 1,880 AVMV/µL, p<0.00004 and 1,245 PMP/µL vs. 1,866 PMP/µL, p=0.003).

CONCLUSION

Severe injury results in endothelial activation and altered MV phenotypes. Significant differences in specific MV phenotypes or changes over time were associated with blood product requirements and the 24 h mortality rate.

Driving perioperative nutrition quality improvement processes forward!

Evidence supporting the important role of nutrition therapy in surgical patients has evolved, with several randomized trials and meta-analyses of randomized trials clearly demonstrating benefits. Despite this evidence, surgeons and anesthesiologists have been slow to adopt recommended practices, and the traditional dogma of delaying the initiation of and restricting the amount of nutrition during the postoperative period persists. Consequently, the nutrition therapy received by surgical patients remains suboptimal; thus, patients suffer worse clinical outcomes. Knowledge translation (KT) describes the process of moving evidence learned from clinical research, and summarized in clinical practice guidelines, to its incorporation into clinical and policy decision making. In this paper, we apply Graham et al's knowledge-to-action model to illuminate our understanding of the issues pertinent to KT in surgical nutrition. We illustrate various components of this model using empirically derived research, commentaries, and published studies from both critical care and surgical nutrition. Barriers to improving surgical nutrition practice may be related to (1) the nature of the underlying evidence and clinical practice guidelines; (2) guideline implementation factors; (3) characteristics of the health system, hospital, and surgical team; (4) provider attitudes and beliefs; and (5) patient factors (eg, type of surgery, underlying disease, and nutrition status). Interventions tailored to overcoming these barriers must be developed, evaluated, and implemented. A system of audit and feedback must guide this process and evaluate improvements over time so that every patient undergoing major surgery will have the opportunity to be optimally assessed and managed according to best nutrition practices.

Incidence and outcome of early acute kidney injury in critically-ill trauma patients

Objective

To determine the incidence and effect on mortality of early acute kidney injury in severely injured trauma patients using the Acute Kidney Injury Network creatinine criteria.

Design

A retrospective cohort study of severely injured trauma patients admitted to the shock trauma intensive care unit.

Setting

Texas Trauma Institute, a state designated level I trauma unit certified by the American College of Surgeons Committee on Trauma.

Patients

901 severely injured trauma patients admitted over a 15 month period to the shock trauma intensive care unit.

Interventions

Retrospective analysis of prospectively collected data abstracted from an electronic trauma database.

Measurements and Main Results

Of 901 eligible patients admitted to the shock trauma intensive care unit after traumatic injury, 54 patients (6%) developed acute kidney injury, of whom 10 (19%) required renal replacement therapy. The 30-day mortality rate for the entire cohort was 83/901 (9.2%). Patients with early acute kidney injury had a mortality rate of 16/54 (29.6%). When corrected for multiple covariates including injury severity scores, the development of early acute kidney injury was associated with a significantly higher risk of death at 30 days with an OR of 3.4 (95% CI 1.6-7.4).

Conclusions

Applying the Acute Kidney Injury Network creatinine criteria in severely injured trauma patients, the incidence of early acute kidney injury was 6%. After correction for injury severity, development of early acute kidney injury was independently associated with significantly higher 30-day mortality.

Bedside ultrasound is a practical and reliable measurement tool for assessing quadriceps muscle layer thickness

BACKGROUND

Critically ill patients commonly experience skeletal muscle wasting that may predict clinical outcome. Ultrasound is a noninvasive method that can measure muscle quadriceps muscle layer thickness (QMLT) and subsequently lean body mass (LBM) at the bedside. However, currently the reliability of these measurements are unknown. The objectives of this study were to evaluate the intra- and interreliability of measuring QMLT using bedside ultrasound.

METHODS

Ultrasound measurements of QMLT were conducted at 7 centers on healthy volunteers. Trainers were instructed to perform measurements twice on each patient, and then a second trainee repeated the measurement. Intrarater reliability measured how consistently the same person measured the subject according to intraclass correlation (ICC). Interrater reliability measured how consistently trainer and trainee agreed when measuring the same subject according to the ICC.

RESULTS

We collected 42 pairs of within operator measurements with an ICC of .98 and 78 pairs of trainer-to-trainee measurements with an ICC of .95. There were no statistically significant differences between the trainer and trainee results (trainer and trainee mean = -0.028 cm, 95% CI = -0.067 to -0.011, P = .1607).

CONCLUSIONS

Excellent intra- and interrater reliability for ultrasound measurements of QMLT in healthy volunteers was observed when performed by a range of providers with no prior ultrasound experience, including dietitians, nurses, physicians, and research assistants. This technique shows promise as a method to evaluate LBM status in ICU or hospital settings and as a method to assess the effects of nutrition and exercise-based interventions on muscle wasting.

Mesenchymal stem cells regulate blood-brain barrier integrity through TIMP3 release after traumatic brain injury

Mesenchymal stem cells (MSCs) may be useful for treating a variety of disease states associated with vascular instability including traumatic brain injury (TBI). A soluble factor, tissue inhibitor of matrix metalloproteinase-3 (TIMP3), produced by MSCs is shown to recapitulate the beneficial effects of MSCs on endothelial function and to ameliorate the effects of a compromised blood-brain barrier (BBB) due to TBI. Intravenous administration of recombinant TIMP3 inhibited BBB permeability caused by TBI, whereas attenuation of TIMP3 expression in intravenously administered MSCs blocked the beneficial effects of the MSCs on BBB permeability and stability. MSCs increased circulating concentrations of soluble TIMP3, which blocked vascular endothelial growth factor-A-induced breakdown of endothelial cell adherens junctions in vitro and in vivo. These findings elucidate a potential molecular mechanism for the beneficial effects of MSCs on the BBB after TBI and demonstrate a role for TIMP3 in the regulation of BBB integrity.

Spray-dried plasma and fresh frozen plasma modulate permeability and inflammation in vitro in vascular endothelial cells

BACKGROUND

After major traumatic injury, patients often require multiple transfusions of fresh frozen plasma (FFP) to correct coagulopathy and to reduce bleeding. A spray-dried plasma (SDP) product has several logistical benefits over FFP use in trauma patients with coagulopathy. These benefits include ease of transport, stability at room temperature, and rapid reconstitution for infusion. Our past work suggests that FFP promotes endothelial stability by inhibiting endothelial permeability.

STUDY DESIGN AND METHODS

The main goal of this project is to determine if solvent-detergent-treated SDP is equivalent to FFP in inhibiting vascular endothelial cell (EC) permeability and inflammation in vitro. Furthermore, this study aimed to determine if solvent-detergent treatment and spray drying of plasma alters the protective effects of FFP on EC function. The five groups tested in our studies are the following: 1) fresh frozen-thawed plasma (FFP); 2) solvent-detergent-treated FFP; 3) solvent-detergent-treated SDP; 4) lactated Ringer's solution; and 5) Hextend.

RESULTS

This study demonstrates that in vitro SDP and FFP equivalently inhibit vascular EC permeability, EC adherens junction breakdown, and endothelial white blood cell binding, an effect that is independent of changes in Vascular Cell Adhesion Molecule 1, Intracellular Adhesion Molecule 1, or E-selectin expression on ECs. Solvent-detergent treatment of FFP does not alter the protective effects of FFP on endothelial cell function in vitro.

CONCLUSION

These data suggest the equivalence of FFP and SDP on modulation of endothelial function and inflammation in vitro.

Enteral glutamine during active shock resuscitation is safe and enhances tolerance of enteral feeding

BACKGROUND

Feeding the hemodynamically unstable patient is increasingly practiced, yet few data exist on its safety. Because enteral glutamine is protective to the gut in experimental models of shock and improves clinical outcomes, it may benefit trauma patients undergoing shock resuscitation and improve tolerance if administered early. This pilot study aimed to evaluate gastrointestinal tolerance and safety of enteral feeding with glutamine, beginning during shock resuscitation in severely injured patients.

METHODS

In a prospective randomized trial, 20 patients were randomly assigned to either an enteral glutamine group (n = 10) or a control group (n = 10). Patients with severe trauma meeting standardized shock resuscitation criteria received enteral glutamine 0.5 g/kg/d during the first 24 hours of resuscitation and 10 days thereafter. Immune-enhancing diet began on postinjury day 1, with a target of 25 kcal/kg/d. Control patients received isonitrogenous whey powder plus immune-enhancing diet. Tolerance (vomiting, nasogastric output, diarrhea, and distention) was assessed throughout the study.

RESULTS

Glutamine was well tolerated and no adverse events occurred. Treated patients had significantly fewer instances of high nasogastric output (5 vs 23; p = .010), abdominal distention (3 vs 12; p = .021), and total instances of intolerance (8 vs 42; p = .011). Intensive care unit (ICU) and hospital length of stay were comparable. Control patients required supplemental parenteral nutrition (PN) to meet goals at day 7.

CONCLUSIONS

Enteral glutamine administered during active shock resuscitation and through the early postinjury period is safe and enhances gastrointestinal tolerance. A large clinical trial is warranted to determine if enteral glutamine administered to the hemodynamically unstable patient can reduce infectious morbidity and mortality.

Association of recall rates with sensitivity and positive predictive values of screening mammography

OBJECTIVE

The performance of screening mammography is measured mainly by its sensitivity, positive predictive value, and cancer detection rate. Recall rates are also suggested as a surrogate measure. The main objective of this study was to measure the effect on sensitivity and positive predictive value as recall rates increase in the community practice of mammography.

MATERIALS AND METHODS

Mammography and pathology data are linked in the Carolina Mammography Registry, a population-based registry of screening mammography. Our mammography database is created from prospectively collected data from mammography facilities; the data include information on the woman and the imaging studies. Our pathology database is created from prospectively collected breast pathology data received from pathology sites and the Central Cancer Registry. Women in the registry who were 40 years old and older and who underwent screening mammography between January 1994 and June 1998 were included. "Recall rate" was defined as the percentage of screening studies for which further workup was recommended by the radiologist.

RESULTS

The study included 215,665 screening mammograms. The mean age of the women was 56 years. The recall rates of the average practice ranged from 1.9% to 13.4%. Sensitivity rose from a mean of 65% in the lowest recall rates to 80.2% at the highest level of recall rates. The positive predictive value of screening decreased from 7.2% in the lowest level of recall to 3.3% in the highest. As recall rates increased, sensitivity increased very little beyond a recall rate of 4.8%, and positive predictive value began decreasing significantly at a recall rate of 5.9%.

CONCLUSION

Practices with recall rates between 4.9% and 5.5% achieve the best trade-off of sensitivity and positive predictive value.

When groups are more competitive than individuals: the domain of the discontinuity effect

The related goals of the research were to delineate the domain of discontinuity, 1st by demonstrating its occurrence in a nonmatrix situation and, 2nd, by establishing the antecedent outcome conditions necessary for producing a discontinuity effect. The 1st goal was met by designing a mixed motive situation involving the production of origami products. Under these conditions, the magnitude of the discontinuity effect did not significantly differ from that in a matrix-only condition. The 2nd goal was met by a separate experiment that used H. H. Kelley and J. W. Thibaut's (1978) analysis of degree of noncorrespondence of outcomes. This experiment demonstrated that as noncorrespondence increased, so did the rate of competitive responding by groups but not by individuals. This pattern was qualified by an interaction with gender such that competitiveness was more markedly affected by noncorrespondence for groups of women than for groups of men.

Interindividual-intergroup discontinuity reduction through the anticipation of future interaction

Consistent with the role of a long-term perspective in reducing the tendency of intergroup relations to be more competitive than interindividual relations in the context of noncorrespondent outcomes, an experiment demonstrated that anticipated future interaction reduced intergroup but not interindividual competitiveness. Further results indicated that the effect was present only for groups composed of members high in abstractness (Openness-Intellect on the Big 5 Inventory and Intuition on the Myers-Briggs Type Inventory) who trusted their opponents.

Diagnostic performance of trauma US in identifying abdominal or pelvic free fluid and serious abdominal or pelvic injury

RATIONALE AND OBJECTIVES

This study assessed the ability of a six-point trauma ultrasound (US) evaluation (a) to identify the presence of free fluid in the abdomen or pelvis, with computed tomography (CT) and laparotomy used as diagnostic standards and (b) to predict the presence of abdominal or pelvic injury, particularly injury requiring surgical intervention.

MATERIALS AND METHODS

Of 156 patients who underwent US evaluation for free fluid after sustaining blunt and penetrating trauma, 147 were entered into the prospective study and underwent follow-up CT and/or laparotomy (n = 79), in-hospital observation, or outpatient examination.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of US for identifying abdominal or pelvic free fluid were 69%, 100%, 100%, 95%, and 95%, respectively. The corresponding values for predicting abdominal and pelvic injury on the basis of free fluid status alone were 57%, 99%, 80%, 96%, and 95%, respectively. Performing repeated US examinations in patients with deteriorating clinical status decreased the false-negative rate by 50%, increasing the sensitivity for free fluid detection to 85% and the negative predictive value to 97%. Similarly, the sensitivity and negative predictive value for detection of injury increased to 71% and 97%, respectively. A learning curve was also observed, with 67% of the false-negative findings occurring in the first 3 months of the 19-month study.

CONCLUSION

A six-point trauma US evaluation can reliably identify abdominal and pelvic free fluid, which can be a reliable indicator of abdominal or pelvic injury. Scanning conditions must be optimized, and the approach to clinical management must be cautious.

Interindividual-intergroup discontinuity reduction through the anticipation of future interaction

Consistent with the role of a long-term perspective in reducing the tendency of intergroup relations to be more competitive than interindividual relations in the context of noncorrespondent outcomes, an experiment demonstrated that anticipated future interaction reduced intergroup but not interindividual competitiveness. Further results indicated that the effect was present only for groups composed of members high in abstractness (Openness-Intellect on the Big 5 Inventory and Intuition on the Myers-Briggs Type Inventory) who trusted their opponents.

Feasibility and profitability of a radiology department providing trauma US as part of a trauma alert team

RATIONALE AND OBJECTIVES

The purpose of this study was to assess the feasibility and profitability of a radiology department providing a six-point trauma ultrasound (US) examination for abdominal or pelvic free fluid as part of a trauma alert team.

MATERIALS AND METHODS

The study included 191 trauma alerts, which generated 156 US examinations. A radiologist and a departmental technologist carried beepers and responded to level I and II traumas. A departmental secretary or technologist recorded when the responding technologist exited and re-entered the department and if US was performed. If performed, the US examination evaluated the four abdominal and pelvic quadrants and the suprapubic and subxiphoid regions. For 64 patients, the responding technologist recorded the times of the trauma alert, emergency room arrival, US start and finish, and return to the radiology department.

RESULTS

Median response, wait, scan duration, and return times were 2, 8, 5, and 7 minutes, respectively. Median costs for the technician, physician, archiving, transcription, and equipment were $8.17, $30.85, $0.97, $4.80, and $41.22, respectively. Reimbursement per examination averaged $110.60. Sensitivity analyses that varied the time spent (median vs mean), US non-use rate (10%-18%), and years of depreciation (5-7 years) yielded net results ranging from a $36.60 profit to a $6.12 loss per examination.

CONCLUSION

A radiology department can profitably respond to trauma alerts and provide a six-point trauma US examination for free fluid.

Does bacteremia pose a direct threat to synthetic vascular grafts?

This study was undertaken to determine the significance of graft lumen exposure to blood-borne organisms in the development of graft infection. Three groups of dogs were studied. In group I (n = 20), the infrarenal aorta was dissected from surrounding tissue, divided, and reconstructed with a Dacron tube interposition graft. In group II (n = 9) the aorta was similarly isolated, but Dacron graft material was wrapped around the intact aorta. In group III (n = 13) the infrarenal aorta was isolated, but no graft material was placed. All dogs were given intravenous 1 X 10(7) Staphylococcus aureus at the completion of surgery. Group I grafts were harvested 8 hours, 1 day, or 21 days after bacterial challenge. Group II and III grafts were harvested 1 day or 21 days after infusion. At the time of harvest, selective cultures of the periaortic tissue (PAT), periaortic graft (PAG), and interposition graft lumen (GL) were taken. The overall infection rates were similar, with 17 of 20 (85%) dogs in group I, 6 of 9 (67%) in group II, and 11 of 13 (85%) in group III found to be culture positive. In group I, 3 of 3 dogs at 8 hours, 2 of 2 on day 1, and 12 of 15 on day 21 had positive PAT cultures. Only 4 of 15 on day 21 had positive GL cultures. In group II, 4 of 5 dogs on day 1 and 2 of 4 on day 21 had positive PAT and PAG cultures. In group III, 9 of 9 animals on day 1 and 2 of 4 on day 21 had positive PAT cultures. All aortic lumen cultures were negative in groups II and III. The difference between GL and PAT cultures was statistically significant in all groups (I, p = 0.01; II, p = 0.05; III, p = 0.01). Serial quantitative blood cultures revealed a mean bacterial load of 10.5 +/- 4.5 CFU/ml at 15 minutes postinfusion, which fell steadily until no bacteria were detected at 3.5 hours. Lymphangiography demonstrated periaortic pooling of lymph in the immediate postoperative period. These data suggest that the bacteremia in this model is transient and rapidly clears. Periaortic tissues quickly sequester bacteria, possibly because of lymphatic leakage. The GL appears to be secondarily infected.