The different paradigms of NK cell death in patients with severe trauma.

Lymphocyte decline, particularly the depletion of NK cells, is a prominent feature of immunosuppression following severe tissue injury, heightening the susceptibility of severe trauma patients to life-threatening infections. Previous research indicates that the reduction in the number of NK cells is closely associated with the process of cell death. Nonetheless, the precise mechanism of NK cell death remains unknown. Here, we discovered that following severe traumatic injury, NK cells undergo several cell death pathways, dominated by apoptosis and pyroptosis with coexistence of necrotic cell death, immunogenic cell death, ferroptosis, and autophagy. These NK cells with different paradigms of death have diverse cytokine expression profiles and diverse interactions with other immune cells. Further exploration revealed that hypoxia was strongly associated with this diverse paradigm of NK cell death. Detailed investigation of paradigms of cell death may help to enhance comprehension of lymphopenia post-severe trauma, to develop new strategy in preventing immunosuppression, and then to improve outcome for severe trauma population.

The incidence, clinical characteristics, and outcome of polytrauma patients with the combination of pulmonary contusion, flail chest and upper thoracic spinal injury.

BACKGROUND: Chest trauma was the third most common cause of death in polytrauma patients, accounting for 25% of all deaths from traumatic injury. Chest trauma involves in injury to the bony thorax, intrathoracic organs and thoracic medulla. This study aimed to investigate the incidence, clinical characteristics, and outcome of polytrauma patients with pulmonary contusion, flail chest and upper thoracic spinal injury. METHODS: Patients who met inclusion criteria were divided into groups: Pulmonary contusion group (PC); Pulmonary contusion and flail chest group (PC + FC); Pulmonary contusion and upper thoracic spinal cord injury group (PC + UTSCI); Thoracic trauma triad group (TTT): included patients with flail chest, pulmonary contusion and the upper thoracic spinal cord injury coexisted. Outcomes were determined, including 30-day mortality and 6-month mortality. RESULTS: A total 84 patients (2.0%) with TTT out of 4176 polytrauma patients presented to Tongji trauma center. There was no difference in mean ISS among PC + FC group, PC + UTSCI group and TTT group. Patients with TTT had a longer ICU stay (21.4 days vs. 7.5 and 6.2; p<0.01), relatively higher 30-day mortality (40.5% vs. 6.0% and 4.3%; p<0.01), and especially higher 6-month mortality (71.4% vs. 6.5%, 13.0%; p<0.01), compared to patients with PC + FC or with PC + UTSCI. The leading causes of death for patients with TTT were ARDS (44.1%) and pulmonary infection (26.5%) during first 30 days after admission. For those patients who died later than 30 days during the 6 months, the predominant underlying cause of death was MOF (53.8%). CONCLUSIONS: Lethal triad of thoracic trauma (LTTT) were described in this study, which consisting of pulmonary contusion,flail chest and the upper thoracic spine cord injury. Like the classic "lethal triad", there was a synergy between the factors when they coexist, resulting in especially high mortality rates. Polytrauma patients with LTTT were presented relatively high 30-day mortality and 6 months mortality. We should pay much more attention to the patients with LTTT for further minimizing complications and mortality.

Thoracic Spine Fractures with Blunt Aortic Injury: Incidence, Risk Factors, and Characteristics.

BACKGROUND: The coexistence of thoracic fractures and blunt aortic injury (BAI) is potentially catastrophic and easy to be missed in acute trauma settings. Data regarding patients with thoracic fractures complicated with BAI are limited. METHODS: The authors conducted a prospective, observational, single-center study including patients with thoracic burst fractures. A multivariate logistic regression model was developed to determine the risk factors of aortic injury. RESULTS: In total, 124 patients with burst fractures of the thoracic spine were included. The incidence of BAI was 11.3% (14/124) in patients with thoracic burst fractures. Among these patients, 11 patients with BAI were missed diagnoses. The main risk factors of BAI were as follows: Injury severity score (OR 1.184; 95% CI, 1.072-1.308; p = 0.001), mechanism of injury, such as crush (OR 10.474; 95% CI, 1.905-57.579; p = 0.007), flail chest (OR = 4.917; 95% CI, 1.122-21.545; p = 0.035), and neurological deficit (OR = 8.299; 95% CI, 0.999-68.933; p = 0.05). CONCLUSIONS: BAI (incidence 11.3%) is common in patients with burst fractures of the thoracic spine and is an easily missed diagnosis. We must maintain a high suspicion of injury for BAI when patients with thoracic burst fractures present with these high-risk factors.