Increased Incidence and Mortality of Civilian Penetrating Traumatic Brain Injury in Sweden: A Single-Center Registry-Based Study.

BACKGROUND: Penetrating trauma to the head and neck has increased during the past decade in Sweden. The aim of this study was to characterize these injuries and evaluate the outcomes for patients treated at a tertiary trauma center. METHODS: Swedish trauma registry data were extracted on patients with head and neck injuries admitted to Karolinska University Hospital (Stockholm, Sweden) between 2011 and 2019. Outcome information was extracted from hospital records, with the primary endpoints focusing on the physiological outcome measures and the secondary endpoints on the surgical and radiological outcomes. RESULTS: Of 1436 patients with penetrating trauma, 329 with penetrating head and neck injuries were identified. Of the 329 patients, 66 (20%) had suffered a gunshot wound (GSW), 240 (73%) a stab wound (SW), and 23 (7%) an injury from other trauma mechanisms (OTMs). The median age for the corresponding 3 groups of patients was 25, 33, and 21 years, respectively. Assault was the primary intent, with 54 patients experiencing GSWs (81.8%) and 158 SWs (65.8%). Patients with GSWs had more severe injuries, worse admission Glasgow coma scale, motor, scores, and a higher intubation rate at the injury site. Most GSW patients underwent major surgery (59.1%) as the initial procedure and were more likely to have intracranial hemorrhage (21.2%). The 30-day mortality was 45.5% (n = 30) for GSWs, 5.4% (n = 13) for SWs, and 0% (n = 0) for OTMs. There was an annual increase in the incidence and mortality for GSWs and SWs. CONCLUSIONS: Between 2011 and 2019, an increasing annual trend was found in the incidence and mortality from penetrating head and neck trauma in Stockholm, Sweden. GSW patients experienced more severe injuries and intracranial hemorrhage and underwent more surgical interventions compared with patients with SWs and OTMs.

Improved oxygenation in prone positioning of mechanically ventilated patients with COVID-19 acute respiratory distress syndrome is associated with decreased pulmonary shunt fraction: a prospective multicenter study.

BACKGROUND: Prone position is used in acute respiratory distress syndrome and in coronavirus disease 2019 (Covid-19) acute respiratory distress syndrome (ARDS). However, physiological mechanisms remain unclear. The aim of this study was to determine whether improved oxygenation was related to pulmonary shunt fraction (Q's/Q't), alveolar dead space (Vd/Vtalv) and ventilation/perfusion mismatch (V'A/Q'). METHODS: This was an international, prospective, observational, multicenter, cohort study, including six intensive care units in Sweden and Poland and 71 mechanically ventilated adult patients. RESULTS: Prone position increased PaO2:FiO2 after 30 min, by 78% (83-148 mm Hg). The effect persisted 120 min after return to supine (p < 0.001). The oxygenation index decreased 30 min after prone positioning by 43% (21-12 units). Q's/Q't decreased already after 30 min in the prone position by 17% (0.41-0.34). The effect persisted 120 min after return to supine (p < 0.005). Q's/Q't and PaO2:FiO2 were correlated both in prone (Beta -137) (p < 0.001) and in the supine position (Beta -270) (p < 0.001). V'A/Q' was unaffected and did not correlate to PaO2:FiO2 (p = 0.8). Vd/Vtalv increased at 120 min by 11% (0.55-0.61) (p < 0.05) and did not correlate to PaO2:FiO2 (p = 0.3). The ventilatory ratio increased after 30 min in the prone position by 58% (1.9-3.0) (p < 0.001). PaO2:FiO2 at baseline predicted PaO2:FiO2 at 30 min after proning (Beta 1.3) (p < 0.001). CONCLUSIONS: Improved oxygenation by prone positioning in COVID-19 ARDS patients was primarily associated with a decrease in pulmonary shunt fraction. Dead space remained high and the global V'A/Q' measure could not explain the differences in gas exchange.

Prehospital and emergency department airway management of severe penetrating trauma in Sweden during the past decade.

BACKGROUND: Prehospital tracheal intubation (TI) is associated with increased mortality in patients with penetrating trauma, and the utility of prehospital advanced airway management is debated. The increased incidence of deadly violence in Sweden warrants a comprehensive evaluation of current airway management for patients with penetrating trauma in the Swedish prehospital environment and on arrival in the emergency department (ED). METHODS: This was an observational, multicenter study of all patients with penetrating trauma and injury severity scores (ISSs) ≥ 15 included in the Swedish national trauma register (SweTrau) between 2011 and 2019. We investigated the frequency and characteristics of prehospital and ED TI, including 30-day mortality and patient characteristics associated with TI. RESULT: Of 816 included patients, 118 (14.5%) were intubated prehospitally, and 248 (30.4%) were intubated in the ED. Patients who were intubated prehospitally had a higher ISS, 33 (interquartile range [IQR] 25, 75), than those intubated in the ED, 25 (IQR 18, 34). Prehospital TI was associated with a higher associated mortality, OR 4.26 (CI 2.57, 7.27, p < 0.001) than TI in the ED, even when adjusted for ISS (OR 2.88 [CI 1.64, 5.14, p < 0.001]). Hemodynamic collapse (≤ 40 mmHg) and low GCS score (≤ 8) were the characteristics most associated with prehospital TI. Traumatic cardiac arrests (TCAs) occurred in 154 (18.9%) patients, of whom 77 (50%) were intubated prehospitally and 56 (36.4%) were intubated in the ED. A subgroup analysis excluding TCA showed that patients with prehospital TI did not have a higher mortality rate than those with ED TI, OR 2.07 (CI 0.93, 4.51, p = 0.068), with OR 1.39 (0.56, 3.26, p = 0.5) when adjusted for ISS. CONCLUSION: Prehospital TI was associated with a higher mortality rate than those with ED TI, which was specifically related to TCA; intubation did not affect mortality in patients without cardiac arrest. Mortality was high when airway management was needed, regardless of cardiac arrest, thereby emphasizing the challenges posed when anesthesia is needed. Several interventions, including whole blood transfusions, the implementation of second-tier EMS units and measures to shorten scene times, have been initiated in Sweden to counteract these challenges.

Prehospital transportation of severe penetrating trauma victims in Sweden during the past decade: a police business?

INTRODUCTION: Sweden is facing a surge of gun violence that mandates optimized prehospital transport approaches, and a survey of current practice is fundamental for such optimization. Management of severe, penetrating trauma is time sensitive, and there may be a survival benefit in limiting prehospital interventions. An important aspect is unregulated transportation by police or private vehicles to the hospital, which may decrease time but may also be associated with adverse outcomes. It is not known whether transport of patients with penetrating trauma occurs outside the emergency medical services (EMS) in Sweden and whether it affects outcome. METHOD: This was a retrospective, descriptive nationwide study of all patients with penetrating trauma and injury severity scores (ISSs) ≥ 15 registered in the Swedish national trauma registry (SweTrau) between June 13, 2011, and December 31, 2019. We hypothesized that transport by police and private vehicles occurred and that it affected mortality. RESULT: A total of 657 patients were included. EMS transported 612 patients (93.2%), police 10 patients (1.5%), and private vehicles 27 patients (4.1%). Gunshot wounds (GSWs) were more common in police transport, 80% (n = 8), compared with private vehicles, 59% (n = 16), and EMS, 32% (n = 198). The Glasgow coma scale score (GCS) in the emergency department (ED) was lower for patients transported by police, 11.5 (interquartile range [IQR] 3, 15), in relation to EMS, 15 (IQR 14, 15) and private vehicles 15 (IQR 12.5, 15). The 30-day mortality for EMS was 30% (n = 184), 50% (n = 5) for police transport, and 22% (n = 6) for private vehicles. Transport by private vehicle, odds ratio (OR) 0.65, (confidence interval [CI] 0.24, 1.55, p = 0.4) and police OR 2.28 (CI 0.63, 8.3, p = 0.2) were not associated with increased mortality in relation to EMS. CONCLUSION: Non-EMS transports did occur, however with a low incidence and did not affect mortality. GSWs were more common in police transport, and victims had lower GCS scorescores when arriving at the ED, which warrants further investigations of the operational management of shooting victims in Sweden.

An Experimental Cold Gas Cannon for the Study of Porcine Lung Contusion and Behind Armor Blunt Trauma.

Behind armor blunt trauma (BABT) is a non-penetrating injury caused by the rapid deformation of body armor, by a projectile, which may in extreme circumstances cause death. The understanding of the mechanisms is still low, in relation to what is needed for safety threshold levels. Few models of graded kinetic energy transfer to the body exist. We established an experimental model for graded BABT. The cold gas cannon was air-driven, consisted of a pressure vessel, a barrel, and a pressure actuator. It required short training to operate and was constructed by standard components. It produced standardized expulsion of plastic projectiles with 65 mm and weight 58 g. Velocity correlated linearly to pressure (R 0.9602, p < 0.0001), equation Y = 6.558*X + 46.50. Maximum tested pressure was 10 bar, velocity 110 m/s and kinetic energy (Ek) 351 J. Crossbred male swine (n = 10) mean weight (SD) 56 ± 3 kg, were subjected to BABT, mean Ek (SD) 318 (61) J, to a fix point on the right lateral thorax. Pulmonary contusion was confirmed by physiological parameters pO2 (p < 0.05), SaO2 (p < 0.01), pCO2 (p < 0.01), etCO2 (p < 0.01), MPAP (p < 0.01), Cstat (p < 0.01), intrapulmonary shunt (Q's/Q't) (p < 0.05), and qualified trans-thoracic ultrasound (p < 0.0001). The consistent injury profile enabled for the addition of future experimental interventions.

Permissive hypoventilation equally effective to maintain oxygenation as positive pressure ventilation after porcine class III hemorrhage and whole blood resuscitation.

BACKGROUND: Prehospital anesthesia may lead to circulatory collapse after severe hemorrhage. It is possible that permissive hypoventilation, refraining from tracheal intubation and accepting spontaneous ventilation, decreases this risk, but it is not known if oxygen delivery can be maintained. We investigated the feasibility of permissive hypoventilation after class III hemorrhage and whole blood resuscitation in three prehospital phases: 15 min on-scene, 30 min whole blood resuscitation, and 45 min after. STUDY DESIGN AND METHODS: 19 crossbred swine, mean weight 58.5 kg, were anesthetized with ketamine/midazolam and hemorrhaged to a mean (SD) 1298 (220) mL (33%) and randomized to permissive hypoventilation (n = 9) or positive pressure ventilation with FiO2 21% (n = 10). RESULTS: In permissive hypoventilation versus positive pressure ventilation, indexed oxygen delivery (DO2 I) decreased to mean (SD) 4.73 (1.06) versus 3.70 (1.13) mL min-1 kg-1 after hemorrhage and increased to 8.62 (2.09) versus 6.70 (1.56) mL min-1 kg-1 at completion of resuscitation. DO2 I, indexed oxygen consumption (VO2 I), and arterial saturation (SaO2 ) did not differ. Permissive hypoventilation increased the respiratory rate and increased pCO2 . Positive pressure ventilation did not deteriorate circulation. Cardiac index (CI), systolic arterial pressure (SAP), hemoglobin (Hb), and heart rate did not differ. DISCUSSION: Permissive hypoventilation and positive pressure ventilation were equally effective to maintain oxygen delivery in all phases. A respiratory rate of 40 was feasible, showing no signs of respiratory fatigue for 90 min, indicating that whole blood resuscitation may be prioritized in select patients with severe hemorrhage and spontaneous breathing.

Intermittent thoracic resuscitative endovascular balloon occlusion of the aorta improves renal function compared to 60 min continuous application after porcine class III hemorrhage.

BACKGROUND: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may be considered for stabilization of patients with hemorrhage from below the diaphragm. Occluding the aorta is a powerful means of hemorrhagic control but is also associated with acute kidney injury, which increases mortality in trauma patients. Allowing for intermittent distal blood flow during REBOA application (iREBOA) could decrease this risk, but circulatory consequences have not been sufficiently elucidated. Therefore, we investigated circulatory effects and the renal artery blood flow (RBF) in iREBOA versus continuous, complete aortic occlusion (cREBOA). METHODS: In a porcine model of uncontrolled class III hemorrhage (34% estimated total blood volume, mean 1360 mL), swine (n = 12, mean weight 60.3 kg) were randomly assigned to iREBOA: 3-min full deflation every 10 min (n = 6), or cREBOA (n = 6), for 60 min of thoracic (zone I) application. The animals then underwent 60 min of reperfusion (critical care phase). RESULTS: Survival was 100% in iREBOA and 83% in cREBOA. The intermittent balloon deflation protocol was hemodynamically tolerable in 63% of reperfusion intervals. Systolic blood pressure decreased during the reperfusion intervals in iREBOA animals (mean 108 mm Hg versus 169 mm Hg; p < 0.005). No differences were detected in heart rate, cardiac output or stroke volume between methods. Troponin I increased in cREBOA after 60 min (mean 666-187 ng/L, p < 0.05). The norepinephrine requirement increased in cREBOA during reperfusion (mean infusion time 12.5-5.5 min; p < 0.05). Total ischemic time decreased in iREBOA (60.0-48.6 min; p < 0.001). RBF increased in iREBOA during balloon deflations and after 60 min reperfusion (61%-39% of baseline RBF; p < 0.05). Urine output increased in iREBOA (mean 135-17 mL; p < 0.001). Nephronal osteopontin, a marker of ischemic injury, increased in cREBOA (p < 0.05). CONCLUSION: iREBOA was survivable, did not cause rebleeding, decreased the total ischemic time and increased the renal blood flow, urine output and decreased renal ischemic injury compared to cREBOA. Intermittent reperfusions during REBOA may be preferred to be continuous, complete occlusion in prolonged application to improve renal function.

Comparison of emergency surgical cricothyroidotomy and percutaneous cricothyroidotomy by experienced airway providers in an obese, in vivo porcine hemorrhage airway model.

BACKGROUND: Emergency front-of-neck airway (eFONA) is a life-saving procedure in "cannot intubate, cannot oxygenate" (CICO). The fastest and most reliable method of eFONA has not been determined. We compared two of the most advocated approaches: surgical cricothyroidotomy and percutaneous cricothyroidotomy, in an obese, in vivo porcine hemorrhage model, designed to introduce real-time physiological feedback, relevant and high provider stress. The primary aim was to determine the fastest method to secure airway. Secondary aims were arterial saturation and partial pressure of oxygen, proxy survival and influence of experience. METHODS: Twelve pigs, mean weight (standard deviation, SD) (60.3 ± 4.1) kg, were anesthetized and exposed to 25-35% total blood volume hemorrhage before extubation and randomization to Seldinger technique "percutaneous cricothyroidotomy" (n = 6) or scalpel-bougie-tube technique "surgical cricothyroidotomy" (n = 6). Specialists in anesthesia and intensive care in a tertiary referral hospital performed the eFONA, simulating an actual CICO-situation. RESULTS: In surgical cricothyroidotomy vs. percutaneous cricothyroidotomy, the median (interquartile range, IQR) times to secure airway were 109 (IQR 71-130) s and 298 (IQR 128-360) s (P = 0.0152), arterial blood saturation (SaO2) were 74.7 (IQR 46.6-84.2) % and 7.9 (IQR 4.1-15.6) % (P = 0.0167), pO2 were 7.0 (IQR 4.7-7.7) kPa and 2.0 (IQR 1.1-2.9) kPa (P = 0.0667), and times of cardiac arrest (proxy survival) were 137-233 s, 190 (IQR 143-229), from CICO. All six animals survived surgical cricothyroidotomy, and two of six (33%) animals survived percutaneous cricothyroidotomy. Years in anesthesia, 13.5 (IQR 7.5-21.3), did not influence time to secure airway. CONCLUSION: eFONA by surgical cricothyroidotomy was faster and had increased oxygenation and survival, when performed under stress by board certified anesthesiologists, and may be an indication of preferred method in situations with hemorrhage and CICO, in obese patients.

Evaluation of an extracorporeal ozone-based bactericide system for the treatment of Escherichia coli sepsis.

BACKGROUND: Sepsis is associated with substantial mortality rates. Antibiotic treatment is crucial, but global antibiotic resistance is now classified as one of the top ten global public health risks facing humanity. Ozone (O3) is an inorganic molecule with no evident function in the body. We investigated the bactericide properties of ozone, using a novel system of extracorporeal ozone blood treatment. We hypothesized that ozone would decrease the concentration of viable Escherichia coli (E. coli) in human whole blood and that the system would be technically feasible and physiologically tolerable in a clinically relevant model of E. coli sepsis in swine. METHODS: The E. coli strain B09-11822, a clinical isolate from a patient with septic shock was used. The in vitro study treated E. coli infected human whole blood (n = 6) with ozone. The in vivo 3.5-h sepsis model randomized swine to E. coli infusion and ozone treatment (n = 5) or E. coli infusion and no ozone treatment (n = 5). Live E. coli, 5 × 107 colony-forming units (CFU/mL) was infused in a peripheral vein. Ozone treatment was initiated with a duration of 30 min after 1.5 h. RESULTS: The single pass in vitro treatment decreased E. coli by 27%, mean 1941 to 1422 CFU/mL, mean of differences - 519.0 (95% CI - 955.0 to - 82.98, P = 0.0281). pO2 increased (95% CI 31.35 to 48.80, P = 0.0007), pCO2 decreased (95% CI - 3.203 to - 1.134, P = 0.0069), oxyhemoglobin increased (95% CI 1.010 to 3.669, P = 0.0113). Methemoglobin was not affected. In the sepsis model, 9/10 swine survived. One swine randomized to ozone treatment died from septic shock before initiation of the treatment. Circulatory, respiratory, and metabolic parameters were not affected by the ozone treatment. E. coli in arterial blood, in organs and in aerobic and anaerobic blood cultures did not differ. Hemoglobin, leucocytes, and methemoglobin were not affected by the treatment. CONCLUSIONS: Ozone decreased the concentration of viable E. coli in human whole blood. The system was technically feasible and physiologically tolerable in porcine sepsis/septic shock and should be considered for further studies towards clinical applications.

Blast polytrauma with hemodynamic shock, hypothermia, hypoventilation and systemic inflammatory response: description of a new porcine model.

PURPOSE: In the past decade blast injuries have become more prevalent. Blast trauma may cause extensive injuries requiring improved early resuscitation and prevention of haemorrhage. Randomized prospective trials are logistically and ethically challenging, and large animal models are important for further research efforts. Few severe blast trauma models have been described, which is why we aimed to establish a comprehensive polytrauma model in accordance with the criteria of the Berlin definition of polytrauma and with a survival time of > 2 h. Multiple blast injuries to the groin and abdomen were combined with hypoperfusion, respiratory and metabolic acidosis, hypoventilation, hypothermia and inflammatory response. The model was compared to lung contusion and haemorrhage. METHODS: 16 landrace swine (mean weight 60.5 kg) were randomized to "control" (n = 5), "chest trauma/hem" by lung contusion and class II haemorrhage (n = 5), and "blast polytrauma" caused by multiple blast injuries to the groin and abdomen, class II haemorrhage, lipopolysaccharide (LPS) infusion and hypothermia 32 °C (n = 6). RESULTS: The blast polytrauma group had an Injury Severity Score of 57 which resulted in haemodynamic shock, hypothermia, respiratory and metabolic acidosis and inflammatory response. The chest trauma/hem group had an Injury Severity Score of 9 and less profound physiologic effects. Physiologic parameters presented a dose-response relationship corresponding to the trauma levels. CONCLUSION: A comprehensive blast polytrauma model fulfilling the Berlin polytrauma criteria, with a high trauma load and a survival time of > 2 h was established. A severe, but consistent, injury profile was accomplished enabling the addition of experimental interventions in future studies, particularly of immediate resuscitation efforts including whole blood administration, trauma packing and haemostasis.

Increased crystalloid fluid requirements during zone 3 Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) versus Abdominal Aortic and Junctional Tourniquet (AAJT) after class II hemorrhage in swine.

PURPOSE: Pelvic and lower junctional hemorrhage result in a significant amount of trauma related deaths in military and rural civilian environments. The Abdominal Aortic and Junctional Tourniquet (AAJT) and infra-renal (zone 3) Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) are two options for resuscitation of patients with life threatening blood loss from and distal to the pelvis. Evidence suggest differences in the hemodynamic response between AAJT and zone 3 REBOA, but fluid management during resuscitation with the devices has not been fully elucidated. We compared crystalloid fluid requirements (Ringer's acetate) between these devices to maintain a carotid mean arterial pressure (MAP) > 60 mmHg. METHODS: 60 kg anesthetized and mechanically ventilated male pigs were subjected to a mean 1030 (range 900-1246) mL (25% of estimated total blood volume, class II) haemorrhage. AAJT (n = 6) or zone 3 REBOA (n = 6) were then applied for 240 min. Crystalloid fluids were administered to maintain carotid MAP. The animals were monitored for 30 min after reperfusion. RESULTS: Cumulative resuscitative fluid requirements increased 7.2 times (mean difference 2079 mL; 95% CI 627-3530 mL) in zone 3 REBOA (mean 2412; range 800-4871 mL) compared to AAJT (mean 333; range 0-1000 mL) to maintain target carotid MAP. Release of the AAJT required vasopressor support with norepinephrine infusion for a mean 9.6 min (0.1 µg/kg/min), while REBOA release required no vasopressor support. CONCLUSION: Zone 3 REBOA required 7.2 times more crystalloids to maintain the targeted MAP. The AAJT may therefore be considered in a situation of hemorrhagic shock to limit the need for crystalloid infusions, although removal of the AAJT caused more severe hemodynamic and metabolic effects which required vasopressor support.

An Experimental Model for the Study of Underwater Pressure Waves on the Central Nervous System in Rodents: A Feasibility Study.

Underwater blast differs from blast in air. The increased density and viscosity of water relative to air cause injuries to occur almost exclusively as primary blast, and may cause disorientation in a diver, which may lead to inability to protect the airway and cause drowning. However, cognitive impairments from under water blast wave exposure have not been properly investigated, and no experimental model has been described. We established an experimental model (water shock tube) for simulating the effects of underwater blast pressure waves in rodents, and to investigate neurology in relation to organ injury. The model produced standardized pressure waves (duration of the primary peak 3.5 ms, duration of the entire complex waveform including all subsequent reflections 325 ms, mean impulse 141-281 kPa-ms, mean peak pressure 91-194 kPa). 31 rats were randomized to control (n = 6), exposure 90 kPa (n = 8), 152 kPa (n = 8), and 194 kPa (n = 9). There was a linear trend between the drop height of the water shock tube and electroencephalography (EEG) changes (p = 0.014), while no differences in oxygen saturation, heart rate, S100b or macroscopic bleedings were detected. Microscopic bleedings were detected in lung, intestines, and meninges. Underwater pressure waves caused changes in EEG, at pressures when mild hemorrhage occurred in organs, suggesting an impact on brain functions. The consistent injury profile enabled for the addition of future experimental interventions.

An observational study of intermediate- or high-dose thromboprophylaxis for critically ill COVID-19 patients.

BACKGROUND: Critically ill COVID-19 patients have a high reported incidence of thromboembolic complications and the optimal dose of thromboprophylaxis is not yet determined. The aim of this study was to investigate if 90-day mortality differed between patients treated with intermediate- or high-dose thromboprophylaxis. METHOD: In this retrospective study, all critically ill COVID-19 patients admitted to intensive care from March 6th until July 15th, 2020, were eligible. Patients were categorized into groups according to daily dose of thromboprophylaxis. Dosing was based on local standardized recommendations, not on degree of critical illness or risk of thrombosis. Cox proportional hazards regression was used to estimate hazard ratios of death within 90 days from ICU admission. Multivariable models were adjusted for sex, age, body-mass index, Simplified Acute Physiology Score III, invasive respiratory support, glucocorticoids, and dosing strategy of thromboprophylaxis. RESULTS: A total of 165 patients were included; 92 intermediate- and 73 high-dose thromboprophylaxis. Baseline characteristics did not differ between groups. The 90-day mortality was 19.6% in patients with intermediate-dose and 19.2% in patients with high-dose thromboprophylaxis. Multivariable hazard ratio of death within 90 days was 0.74 (95% CI, 0.36-1.53) for the high-dose group compared to intermediate-dose group. Multivariable hazard ratio for thromboembolic events and bleedings within 28 days was 0.93 (95% CI 0.37-2.29) and 0.84 (95% CI 0.28-2.54) for high versus intermediate dose, respectively. CONCLUSIONS: A difference in 90-day mortality between intermediate- and high-dose thromboprophylaxis could neither be confirmed nor rejected due to a small sample size.

Incidence, Demographics, and Outcomes of Penetrating Trauma in Sweden During the Past Decade.

Trauma injury is the sixth leading cause of death worldwide, and interpersonal violence is one of the major contributors in particular regarding injuries to the head and neck. The incidence, demographics, and outcomes of penetrating trauma reaching hospitals in Sweden are not known. We report the largest, nationwide epidemiological study of penetrating injuries in Sweden, using the Swedish Trauma Registry (SweTrau). A multi-center retrospective descriptive study of 4,776 patients was conducted with penetrating injuries in Sweden, between 2012 and 2018. Due to the increase in coverage of the SweTrau registry during the same period, we chose to analyze the average number of cases for the time intervals 2013-2015 and 2016-2018 and compare those trends to the reports of the Swedish National Council for Crime Prevention (Brå) as well. A total of 663 patients had Injury Severity Score (ISS) ≥ 15 at admission and were included in the study. Three hundred and sixty-eight (55.5%) were stab wounds (SW), 245 (37.0%) gunshot wounds (GSW), and 50 (7.5%) other traumas. A majority of the cases involved injuries to the head, neck, and face. SW increased from 145 during 2013-2015 to 184 during the second period of 2016-2018. The increase was greater for GSW from 92 to 141 during the same respective periods. This trend of increase over time was also seen in head, neck, and face injuries. The 30-day mortality was unaffected (48-47%) in GSW and trended toward lower in SW (24-21%) when comparing 2013-2015 with 2016-2018. Patients with head trauma had 45% mortality compared to 18% for non-head trauma patients. Head trauma also resulted in worse outcomes, only 13% had Glasgow outcome score (GOS) 5 compared to 27% in non-head trauma. The increasing number of cases of both SW and GSW corresponded well with reports from Brå although further studies also are needed to address deaths outside of hospitals and not registered at the SweTrau. The majority of cases had injuries to the head, neck, and face and were associated with higher mortality and poor outcomes. Further studies are needed to understand the contributing factors to these worse outcomes in Sweden and whether more targeted trauma care of these patients can improve outcomes.

Pulmonary hypoxia and venous admixture correlate linearly to the kinetic energy from porcine high velocity projectile behind armor blunt trauma.

Purpose. Behind armor blunt trauma (BABT) is a non-penetrating injury caused by the rapid deformation of body armor, by a projectile, which may in extreme circumstances cause death. The understanding of the mechanisms is still low, in relation to what is needed for safety threshold levels. High velocity projectile BABT causes immediate and severe hypoxia by increased venous admixture (Q's/Q't), but it is not known whether the level of hypoxia correlates to the kinetic energy (Ek) of the projectile.Materials and Methods. We constructed a 65 mm BABT-simulator to measure the Ek absorbed by the thorax. The simulator was validated to 7.62 mm high velocity BABT (swine with removed organs) for 7.62 mm (n = 7) and 65 mm (n = 12). Physiological measurements during 60 minutes were performed in 40 anesthetized swine in groups control (n = 9), 7.62 mm (n = 7), 65 mm weight variation (n = 24), 65 mm speed variation (n = 12, included in the weight variation group). New calculations were done for a previously studied group of 7.62 mm with backing (n = 9).Results. 65 mm BABT simulation and 7.62 mm BABT had similar back-face signatures (24 mm), and maximum thoracic impression speed (24-34 m/s). Back-face signatures correlated linearly to Ek (R2=0.20). Rib fractures had a 50% likelihood at back-face signature 23.0 mm (95% CI 18.5 to 29.0 mm, area under ROC curve 0.93). Ek correlated linearly to pO2 (R2=0.34, p = 0.0026) and venous admixture (R2=0.37, p = 0.0046). The extrapolated Ek at 5 minutes for pO2=0 kPa was 587 J and for venous admixture = 100% 574 J.Conclusions. Hypoxia and venous admixture correlated linearly to Ek, allowing for a calculated predicted lethal Ek to ≥574 J, which should be verified in survival studies. Lethality predictions from lung physiology is an alternative to clay impressions and may facilitate the development of ballistic safety equipment and new BABT safety criteria.Supplemental data for this article is available online at https://doi.org/10.1080/01902148.2021.1950869 .

Pediatric Prehospital Advanced Airway Management by Anesthesiologist and Nurse Anesthetist Staffed Critical Care Teams.

INTRODUCTION: Prehospital pediatric tracheal intubation (TI) is a possible life-saving intervention that requires adequate experience to mitigate associated complications. The pediatric airway and respiratory physiology present challenges in addition to a relatively rare incidence of prehospital pediatric TI. STUDY OBJECTIVE: The aim of this study was to describe characteristics and outcomes of prehospital TI in pediatric patients treated by critical care teams. METHODS: This is a sub-group analysis of all pediatric (<16 years old) patients from a prospective, observational, multi-center study on prehospital advanced airway management in the Nordic countries from May 2015 through November 2016. The TIs were performed by anesthesiologists and nurse anesthetists staffing six helicopter and six Rapid Response Car (RRC) prehospital critical care teams. RESULTS: In the study, 74 children were tracheal intubated, which corresponds to 3.7% (74/2,027) of the total number of patients. The pediatric patients were intubated by very experienced providers, of which 80% had performed ≥2,500 TIs. The overall TI success rate, first pass success rate, and airway complication rate were in all children (<16 years) 98%, 82%, and 12%. The corresponding rates among infants (<2 years) were 94%, 67%, and 11%. The median time on scene was 30 minutes. CONCLUSION: This study observed a high overall prehospital TI success rate in children with relatively few associated complications and short time on scene, despite the challenges presented by the pediatric prehospital TI.

Pre-hospital emergency anaesthesia in trauma patients treated by anaesthesiologist and nurse anaesthetist staffed critical care teams.

BACKGROUND: Pre-hospital tracheal intubation in trauma patients has recently been questioned. However, not only the trauma and patient characteristics but also airway provider competence differ between systems making simplified statements difficult. METHOD: The study is a subgroup analysis of trauma patients included in the PHAST study. PHAST was a prospective, observational, multicentre study on pre-hospital advanced airway management by anaesthesiologist and nurse anaesthetist manned pre-hospital critical care teams in the Nordic countries May 2015-November 2016. Endpoints include intubation success rate, complication rate (airway-related complication according to Utstein Airway Template by Sollid et al), scene time (time from arrival of the critical care team to departure of the patient) and pre-hospital mortality. RESULT: The critical care teams intubated 385 trauma patients, of which 65 were in shock (SBP <90 mm Hg), during the study. Of the trauma patients, 93% suffered from blunt trauma, the mean GCS was 6 and 75% were intubated by an experienced provider who had performed >2500 tracheal intubations. The pre-hospital tracheal intubation overall success rate was 98.6% and the complication rate was 13.6%, with no difference between patients with or without shock. The mean scene time was significantly shorter in trauma patients with shock (21.4 min) compared to without shock (21.4 vs 25.1 min). Following pre-hospital tracheal intubation, 97% of trauma patients without shock and 91% of the patients in shock with measurable blood pressure were alive upon arrival to the ED. CONCLUSION: Pre-hospital tracheal intubation success and complication rates in trauma patients were comparable with in-hospital rates in a system with very experienced airway providers. Whether the short scene times contributed to a low pre-hospital mortality needs further investigation in future studies.

The swine as a vehicle for research in trauma-induced coagulopathy: Introducing principal component analysis for viscoelastic coagulation tests.

BACKGROUND: Uncontrolled bleeding is the leading cause of potentially preventable deaths among trauma patients. Tissue injury and shock result in trauma-induced coagulopathy (TIC). There are still uncertainties regarding detection methods and best practice management for TIC, and a deeper understanding of the pathophysiology requires robust animal models. The applicability of swine in coagulation studies, particularly after trauma has not been sufficiently elucidated. We, therefore, evaluated the swine as a vehicle for TIC research in a selection of trauma modalities. METHODS: Twenty-six landrace swine (3 females/23 males) (mean weight, 60.0 kg) were anesthetized and randomized to negative controls, receiving no manipulation (n = 5), positive controls by hemodilution (n = 5), pulmonary contusion without hemorrhage (n = 5), pulmonary contusion with hemorrhage (n = 5), and blast polytrauma with hypothermia, hypoperfusion, hypoventilation, and systemic inflammation (n = 6). A comprehensive coagulation panel was analyzed at baseline, 20 minutes and 120 minutes after trauma. RESULTS: PT(INR), aPTT, thrombocytes, and fibrinogen did not change after trauma. D-dimer increased (p < 0.0001), prothrombin decreased (p < 0.05) and aPC decreased (p < 0.01) after polytrauma. PAI-1 decreased after pulmonary contusion with hemorrhage (p < 0.05). Positive controls displayed changes in PT(INR), thrombocytes, fibrinogen, prothrombin, aPC (p < 0.05). Principal Component Analysis of rotational thromboelastometry presented pathologic coagulation profiles in both polytrauma and positive control groups with vectors extending outside the 95% confidence interval, which were not detected in negative controls. CONCLUSION: Coagulopathy was induced after severe porcine blast polytrauma, specifically detected in rotational thromboelastometry. A novel method for principal component analysis of viscoelastic tests was introduced which may increase the detection sensitivity and differentiation of TIC phenotypes and should be further investigated in trauma populations.

Prone positioning in mechanically ventilated patients with severe acute respiratory distress syndrome and coronavirus disease 2019.

BACKGROUND: The management of COVID-19 ARDS is debated. Although current evidence does not suggest an atypical acute respiratory distress syndrome (ARDS), the physiological response to prone positioning is not fully understood and it is unclear which patients benefit. We aimed to determine whether proning increases oxygenation and to evaluate responders. METHODS: This case series from a single, tertiary university hospital includes all mechanically ventilated patients with COVID-19 and proning between 17 March 2020 and 19 May 2020. The primary measure was change in PaO2 :FiO2 . RESULTS: Forty-four patients, 32 males/12 females, were treated with proning for a total of 138 sessions, with median (range) two (1-8) sessions. Median (IQR) time for the five sessions was 14 (12-17) hours. In the first session, median (IQR) PaO2 :FiO2 increased from 104 (86-122) to 161 (127-207) mm Hg (P < .001). 36/44 patients (82%) improved in PaO2 :FiO2 , with a significant increase in PaO2 :FiO2 in the first three sessions. Median (IQR) FiO2 decreased from 0.7 (0.6-0.8) to 0.5 (0.35-0.6) (<0.001). A significant decrease occurred in the first three sessions. PaO2 , tidal volumes, PEEP, mean arterial pressure (MAP), and norepinephrine infusion did not differ. Primarily, patients with PaO2 :FiO2 approximately < 120 mm Hg before treatment responded to proning. Age, sex, BMI, or SAPS 3 did not predict success in increasing PaO2 :FiO2 . CONCLUSION: Proning increased PaO2 :FiO2 , primarily in patients with PaO2 :FiO2 approximately < 120 mm Hg, with a consistency over three sessions. No characteristic was associated with non-responding, why proning may be considered in most patients. Further study is required to evaluate mortality.

Dosing of thromboprophylaxis and mortality in critically ill COVID-19 patients.

BACKGROUND: A substantial proportion of critically ill COVID-19 patients develop thromboembolic complications, but it is unclear whether higher doses of thromboprophylaxis are associated with lower mortality rates. The purpose of the study was to evaluate the association between initial dosing strategy of thromboprophylaxis in critically ill COVID-19 patients and the risk of death, thromboembolism, and bleeding. METHOD: In this retrospective study, all critically ill COVID-19 patients admitted to two intensive care units in March and April 2020 were eligible. Patients were categorized into three groups according to initial daily dose of thromboprophylaxis: low (2500-4500 IU tinzaparin or 2500-5000 IU dalteparin), medium (> 4500 IU but < 175 IU/kilogram, kg, of body weight tinzaparin or > 5000 IU but < 200 IU/kg of body weight dalteparin), and high dose (≥ 175 IU/kg of body weight tinzaparin or ≥ 200 IU/kg of body weight dalteparin). Thromboprophylaxis dosage was based on local standardized recommendations, not on degree of critical illness or risk of thrombosis. Cox proportional hazards regression was used to estimate hazard ratios with corresponding 95% confidence intervals of death within 28 days from ICU admission. Multivariable models were adjusted for sex, age, body mass index, Simplified Acute Physiology Score III, invasive respiratory support, and initial dosing strategy of thromboprophylaxis. RESULTS: A total of 152 patients were included: 67 received low-, 48 medium-, and 37 high-dose thromboprophylaxis. Baseline characteristics did not differ between groups. For patients who received high-dose prophylaxis, mortality was lower (13.5%) compared to those who received medium dose (25.0%) or low dose (38.8%), p = 0.02. The hazard ratio of death was 0.33 (95% confidence intervals 0.13-0.87) among those who received high dose, and 0.88 (95% confidence intervals 0.43-1.83) among those who received medium dose, as compared to those who received low-dose thromboprophylaxis. There were fewer thromboembolic events in the high (2.7%) vs medium (18.8%) and low-dose thromboprophylaxis (17.9%) groups, p = 0.04. CONCLUSIONS: Among critically ill COVID-19 patients with respiratory failure, high-dose thromboprophylaxis was associated with a lower risk of death and a lower cumulative incidence of thromboembolic events compared with lower doses. TRIAL REGISTRATION: Clinicaltrials.gov NCT04412304 June 2, 2020, retrospectively registered.