Factors Predictive of Ventilator-associated Pneumonia in Critically Ill Trauma Patients.

BACKGROUND: Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation. We sought to investigate factors associated with the development of VAP in critically ill trauma patients. METHODS: We conducted a retrospective review of trauma patients admitted to our trauma intensive care unit between 2016 and 2018. Patients with ventilator-associated pneumonia were identified from the trauma database. Data collected from the trauma database included demographics (age, gender and race), mechanism of injury (blunt, penetrating), injury severity (injury severity score "ISS"), the presence of VAP, transfused blood products and presenting vital signs. RESULTS: A total of 1403 patients were admitted to the trauma intensive care unit (TICU) during the study period; of these, 45 had ventilator-associated pneumonia. Patients with VAP were older (p = 0.030), and they had a higher incidence of massive transfusion (p = 0.015) and received more packed cells in the first 24 h of admission (p = 0.028). They had a higher incidence of face injury (p = 0.001), injury to sternum (p = 0.011) and injury to spine (p = 0.024). Patients with VAP also had a higher incidence of acute kidney injury (AKI) (p < 0.001) and had a longer ICU (p < 0.001) and hospital length of stay (p < 0.001). Multiple logistic regression models controlling for age and injury severity (ISS) showed massive transfusion (p = 0.017), AKI (p < 0.001), injury to face (p < 0.001), injury to sternum (p = 0.007), injury to spine (p = 0.047) and ICU length of stay (p < 0.001) to be independent predictors of VAP. CONCLUSIONS: Among critically ill trauma patients, acute kidney injury, injury to the spine, face or sternum, massive transfusion and intensive care unit length of stay were associated with VAP.

Engineering Intravenously Administered Nanoparticles to Reduce Infusion Reaction and Stop Bleeding in a Large Animal Model of Trauma.

Bleeding from traumatic injury is the leading cause of death for young people across the world, but interventions are lacking. While many agents have shown promise in small animal models, translating the work to large animal models has been exceptionally difficult in great part because of infusion-associated complement activation to nanomaterials that leads to cardiopulmonary complications. Unfortunately, this reaction is seen in at least 10% of the population. We developed intravenously infusible hemostatic nanoparticles that were effective in stopping bleeding and improving survival in rodent models of trauma. To translate this work, we developed a porcine liver injury model. Infusion of the first generation of hemostatic nanoparticles and controls 5 min after injury led to massive vasodilation and exsanguination even at extremely low doses. In naïve animals, the physiological changes were consistent with a complement-associated infusion reaction. By tailoring the zeta potential, we were able to engineer a second generation of hemostatic nanoparticles and controls that did not exhibit the complement response at low and moderate doses but did at the highest doses. These second-generation nanoparticles led to cessation of bleeding within 10 min of administration even though some signs of vasodilation were still seen. While the complement response is still a challenge, this work is extremely encouraging in that it demonstrates that when the infusion-associated complement response is managed, hemostatic nanoparticles are capable of rapidly stopping bleeding in a large animal model of trauma.

Tuning ligand density on intravenous hemostatic nanoparticles dramatically increases survival following blunt trauma.

Targeted nanoparticles are being pursued for a range of medical applications. Here we utilized targeted nanoparticles (synthetic platelets) to halt bleeding in acute trauma. One of the major questions that arises in the field is the role of surface ligand density in targeted nanoparticles' performance. We developed intravenous hemostatic nanoparticles (GRGDS-NP1) and previously demonstrated their ability to reduce bleeding following femoral artery injury and increase survival after lethal liver trauma in the rat. These nanoparticles are made from block copolymers, poly(lactic-co-glycolic acid)-b-poly L-lysine-b-poly(ethylene glycol). Surface-conjugated targeting ligand density can be tightly controlled with this system, and here we investigated the effect of varying density on hemostasis and biodistribution. We increased the targeting peptide (GRGDS) concentration 100-fold (GRGDS-NP100) and undertook an in vitro dose-response study using rotational thromboelastometry, finding that GRGDS-NP100 hemostatic nanoparticles were efficacious at doses at least 10 times lower than the GRGDS-NP1. These results were recapitulated in vivo, demonstrating efficacy at eight-fold lower concentration after lethal liver trauma. 1 h survival increased to 92% compared with a scrambled peptide control, 45% (OR = 14.4, 95% CI = [1.36, 143]), a saline control, 47% (OR = 13.5, 95% CI = [1.42, 125]), and GRGDS-NP1, 80% (OR = 1.30, n.s.). This work demonstrates the impact of changing synthetic platelet ligand density on hemostasis and lays the foundation for methods to determine optimal ligand concentration parameters.

Intravenous hemostatic nanoparticles increase survival following blunt trauma injury.

Trauma is the leading cause of death for people ages 1-44, with blood loss comprising 60-70% of mortality in the absence of lethal CNS or cardiac injury. Immediate intervention is critical to improving chances of survival. While there are several products to control bleeding for external and compressible wounds, including pressure dressings, tourniquets, or topical materials (e.g., QuikClot, HemCon), there are no products that can be administered in the field for internal bleeding. There is a tremendous unmet need for a hemostatic agent to address internal bleeding in the field. We have developed hemostatic nanoparticles (GRGDS-NPs) that reduce bleeding times by ~50% in a rat femoral artery injury model. Here, we investigated their impact on survival following administration in a lethal liver resection injury in rats. Administration of these hemostatic nanoparticles reduced blood loss following the liver injury and dramatically and significantly increased 1 h survival from 40 and 47% in controls (inactive nanoparticles and saline, respectively) to 80%. Furthermore, we saw no complications following administration of these nanoparticles. We further characterized the nanoparticles' effect on clotting time (CT) and maximum clot firmness (MCF) using rotational thromboelastometry (ROTEM), a clinical measurement of whole-blood coagulation. Clotting time is significantly reduced, with no change in MCF. Administration of these hemostatic nanoparticles after massive trauma may help staunch bleeding and improve survival in the critical window following injury, and this could fundamentally change trauma care.

Necrotizing soft-tissue infections.

OBJECTIVE: To provide a contemporary review of the diagnosis and management of necrotizing soft-tissue infections. DATA SOURCES: Scientific literature and internet sources. STUDY SELECTION: Major articles of importance in this area. CONCLUSIONS: The mortality for necrotizing soft-tissue infections appears to be decreasing, possibly due to improved recognition and earlier delivery of more effective therapy. Establishing a diagnosis and initiating treatment as soon as possible provides the best opportunity for a good outcome.

Among Trauma Patients, Younger Men with Ventilator-Associated Pneumonia Have Worse Outcomes Compared to Older Men-An Exploratory Study.

BACKGROUND: Ventilator-associated pneumonia is associated with significant morbidity. Although the association of gender with outcomes in trauma patients has been debated for years, recently, certain authors have demonstrated a difference. We sought to compare the outcomes of younger men and women to older men and women, among critically ill trauma patients with ventilator-associated pneumonia (VAP). METHODS: We reviewed our trauma data base for trauma patients with ventilator-associated pneumonia admitted to our trauma intensive care unit between January 2016 and June 2018. Data collected included demographics, injury mechanism and severity (ISS), admission vital signs and laboratory data and outcome measures including hospital length of stay, ICU stay and survival. Patients were also divided into younger (<50) and older (≥50) to account for hormonal status. Linear regression and binary logistic regression models were performed to compare younger men to older men and younger women to older women, and to examine the association between gender and hospital length of stay (LOS), ICU stay (ICUS), and survival. RESULTS: Forty-five trauma patients admitted to our trauma intensive care unit during the study period (January 2016 to August 2018) had ventilator-associated pneumonia. The average age was 58.9 ± 19.6 years with mean ISS of 18.2 ± 9.8. There were 32 (71.1%) men, 27 (60.0%) White, and 41 (91.1%) had blunt trauma. Mean ICU stay was 14.9 ± 11.4 days and mean total hospital length of stay (LOS) was 21.5 ± 14.6 days. Younger men with VAP had longer hospital LOS 28.6 ± 17.1 days compared to older men 16.7 ± 6.6 days, (p < 0.001) and longer intensive care unit stay 21.6 ± 15.6 days compared to older men 11.9 ± 7.3 days (p = 0.02), there was no significant difference in injury severity (ISS was 22.2 ± 8.4 vs. 17 ± 8, p = 0.09). CONCLUSIONS: Among trauma patients with VAP, younger men had longer hospital length of stay and a trend towards longer ICU stay. Further research should focus on the mechanisms behind this difference in outcome using a larger database.

The accuracy of thoracic ultrasound for detection of pneumothorax is not sustained over time: a preliminary study.

BACKGROUND: Ultrasound has proven to be very accurate in the diagnosis of pneumothorax in the trauma suite. It is unknown whether this accuracy is maintained over time in patients with a thoracostomy (TT) in place. METHODS: Hospitalized patients with a TT placed to treat a traumatic pneumothorax underwent serial daily bedside surgeon-performed ultrasound by 1 of 2 experienced surgeon sonographers who were unaware of concomitant X-ray findings. Results were compared with daily chest X-ray films. Data collected included size and day of placement of the chest tube, as well as the results of the serial ultrasounds and the comparative X-ray films. RESULTS: Fourteen patients (78% men, mean age 33 years) sustained traumatic pneumothorax. The causes included stab wound (9), gunshot wound (3), and rib fracture (2). They underwent 126 (median 7) ultrasound evaluations and were followed between 4 and 26 (median 7) days after injury. Of these exams, 95 had a concomitant chest X-ray film within 1 hour of the ultrasound, thus 190 hemithoraces could be analyzed. Eighty-two ultrasounds were performed for hemithoraces that had no injury or TT in place and all 82 revealed normal pleural sliding. No pneumothoraces were noted on concomitant chest X-ray films (100% accuracy). One hundred eight ultrasounds were performed for hemithoraces that had a TT in place. For the first 24 hours, accuracy remained 100%. After 24 hours, however, sensitivity of ultrasound diagnosis of pneumothorax fell to 55%, specificity fell to 70%, positive predictive value to 43%, and negative predictive value to 79%. This led to an overall accuracy rate for ultrasound examination after 24 hours of 65%. CONCLUSIONS: Ultrasound evaluation for pneumothorax is very accurate for the first 24 hours after insertion of a TT, but the accuracy, especially the positive predictive value, is not sustained over time, possibly as a result of the formation of intrapleural adhesions.

Acute massive gastric dilatation causing ischaemic necrosis and perforation of the stomach.

Acute massive gastric dilatation (AMGD) is a rare distinctive condition but associates with high morbidity and mortality. Though usually seen in patients with eating disorders, many aetiologies of AMGD have been described. The distension has been reported to cause gastric necrosis with or without perforation, usually within 1-2 days of an inciting event of AMGD.We report the case of a 58-year-old male who presented with gastric perforation associated with AMGD 11 days after surgical relief of a proximal small bowel obstruction. The AMGD arose from a closed loop obstruction between a tumour at the gastro-oesophageal junction and a small bowel obstruction as a result of volvulus around a jejunal feeding tube.To our knowledge, this is the first case of a closed loop obstruction of this aetiology reported in the literature, and the presentation of this patient's AMGD was notable for the delayed onset of gastric necrosis. The patient underwent an exploratory laparotomy and a partial gastrectomy to excise a portion of his perforated stomach. Surgeons should be aware of the possibility of delayed ischaemic gastric perforation in cases of AMGD.

The Epidemiology of Traumatic Hemothorax in a Level I Trauma Center: Case for Early Video-assisted Thoracoscopic Surgery.

OBJECTIVE: Hemothorax is a common sequela of chest trauma. Complications after chest trauma include retained hemothorax and empyema requiring multiple interventions. We studied the epidemiology of hemothorax and its complications at a level I trauma center. METHODS: The trauma registry was reviewed from Jan 1995 toMay 2005.Allpatients ≥16 years of agewhowere admitted with hemothorax, an AIS chest score of ≥ 3, and did not receive an immediate thoracotomy were entered in the study cohort. The patient demographics, details of the injury event, treatments, hospital length of stay (LOS), complications and outcome were analyzed. RESULTS: The study cohort of 522 patients with a hemothorax were treated with 685 chest thoracostomy tubes. Overall, the median ISS was 18 and 62% were penetrating injuries. 109 patients (21%) had a retained hemothorax and required placement of ≥ 2 chest tubes with a median LOS of 15 days longer than patients with no retained hemothorax (p < 0.0001). The overall complication rate was 5% (26/522). Of these, 20 patients had empyema (3.8%), 8 patients required decortication, and 6 patients received streptokinase treatment. CONCLUSION: More than 1 out of every 5 patients undergoing intervention for trauma-induced hemothorax develops a complication. The development of retained hemothorax is associated with empyema in 15.6% of cases and a 2-week median increase in length of stay. Future research into interventions such as Video-assisted thoracoscopic surgery (VATS) on the day of admission to completely evacuate hemothorax is warranted to reduce complication rates, length of stay and cost.

Opinions of trauma practitioners regarding prehospital interventions for critically injured patients.

BACKGROUND: Significant controversy surrounds the prehospital management of trauma patients. METHODS: A questionnaire describing clinical scenarios was mailed to a random sample of 345 trauma practitioners. RESULTS: The 182 trauma practitioners (52.8%) who returned the surveys were predominantly general or trauma surgeons (83.5%) in academic or university practice (68.1%). For a patient with a severe traumatic brain injury, 84.5% of trauma practitioners recommended that emergency medical services personnel attempt intubation at least once when transport time was 20 to 40 minutes. For a patient with a gunshot wound to the epigastrium in decompensated shock, the majority of trauma practitioners believed that a relatively hypotensive state should be maintained, regardless of transport time. Trauma practitioners (52.2%) have recommended the use of the pneumatic antishock garment for transports of 20 to 40 minutes for patients with an unstable pelvic fracture and decompensated shock. CONCLUSIONS: Most trauma practitioners believe that emergency medical services providers should attempt intubation for a patient with a severe traumatic brain injury, should treat decompensated shock in a patient with penetrating torso trauma but maintain the patient in a relatively hypotensive state, and should apply and inflate the pneumatic antishock garment for a suspected pelvic fracture accompanied by decompensated shock if the patient is 20 to 40 minutes from a trauma center. The recommendations of trauma practitioners regarding appropriate prehospital care are significantly influenced by the time required for transport to the trauma center.