Long-term risk of dementia after acute respiratory failure requiring intensive care unit admission

Experimental Models of Hospital-Acquired Infections After Traumatic Brain Injury: Challenges and Opportunities

Patients hospitalized after a moderate or severe traumatic brain injury (TBI) are at increased risk of nosocomial infections, including bacterial pneumonia and other upper respiratory tract infections. Infections represent a secondary immune challenge for vulnerable TBI patients that can lead to increased morbidity and poorer long-term prognosis. This review first describes the clinical significance of infections after TBI, delving into the known mechanisms by which a TBI can alter systemic immunological responses towards an immunosuppressive state, leading to promotion of increased vulnerability to infections. Pulmonary dysfunction resulting from respiratory tract infections is considered in the context of neurotrauma, including the bidirectional relationship between the brain and lungs. Turning to pre-clinical modeling, current laboratory approaches to study experimental TBI and lung infections are reviewed, to highlight findings from the limited key studies to date that have incorporated both insults. Then, practical decisions for the experimental design of animal studies of post-injury infections are discussed. Variables associated with the host animal, the infectious agent (e.g., species, strain, dose, and administration route), as well as the timing of the infection relative to the injury model are important considerations for model development. Together, the purpose of this review is to highlight the significant clinical need for increased pre-clinical research into the two-hit insult of a hospital-acquired infection after TBI to encourage further scientific enquiry in the field.

The role of immune activation and antigen persistence in acute and long COVID

In late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggered the global coronavirus disease 2019 (COVID-19) pandemic. Although most infections cause a self-limited syndrome comparable to other upper respiratory viral pathogens, a portion of individuals develop severe illness leading to substantial morbidity and mortality. Furthermore, an estimated 10%-20% of SARS-CoV-2 infections are followed by post-acute sequelae of COVID-19 (PASC), or long COVID. Long COVID is associated with a wide variety of clinical manifestations including cardiopulmonary complications, persistent fatigue, and neurocognitive dysfunction. Severe acute COVID-19 is associated with hyperactivation and increased inflammation, which may be an underlying cause of long COVID in a subset of individuals. However, the immunologic mechanisms driving long COVID development are still under investigation. Early in the pandemic, our group and others observed immune dysregulation persisted into convalescence after acute COVID-19. We subsequently observed persistent immune dysregulation in a cohort of individuals experiencing long COVID. We demonstrated increased SARS-CoV-2-specific CD4+ and CD8+ T-cell responses and antibody affinity in patients experiencing long COVID symptoms. These data suggest a portion of long COVID symptoms may be due to chronic immune activation and the presence of persistent SARS-CoV-2 antigen. This review summarizes the COVID-19 literature to date detailing acute COVID-19 and convalescence and how these observations relate to the development of long COVID. In addition, we discuss recent findings in support of persistent antigen and the evidence that this phenomenon contributes to local and systemic inflammation and the heterogeneous nature of clinical manifestations seen in long COVID.

Real-World Evidence for the Association Between Pneumonia-Related Intensive Care Unit Stay and Dementia

OBJECTIVE

There is limited clarity concerning the risk of dementia after pneumonia with intensive care unit (ICU) stay. We conducted a nationwide cohort study, which aimed to investigate the impact of dementia after pneumonia with and without intensive care unit admission.

METHODS

Data was obtained from Taiwan's National Health Insurance Research Database between 2000 and 2015. A total of 7,473 patients were identified as having pneumonia required ICU stay, along with 22,419 controls matched by sex and age. After adjusting for confounding factors, multivariate Cox regression model analysis was used to compare the risk of developing dementia during the 15-years follow-up period.

RESULTS

The enrolled pneumonia patients with ICU admission had a dementia rate of 9.89%. Pneumonia patients without ICU admission had a dementia rate of 9.21%. The multivariate Cox regression model analysis revealed that the patients with ICU stay had the higher risk of dementia, with a crude hazard ratio of 3.371 (95% confidence interval, 3.093-3.675; p<0.001).

CONCLUSION

This study indicated that pneumonia with ICU stay is associated with an increased risk of dementia. A 3-fold risk of dementia was observed in patients admitted to the ICU compared to the control group.

Propofol shows less negative effects on cognitive performances than dexmedetomidine in elderly intensive care unit patients

BACKGROUND

Due to the improved clinical management of aging population and the consequently declined mortality among patients with critical illnesses, the number of survivors from intensive care units (ICUs) keeps rising. Studies to examine the association of cognitive impairment analgesic and sedation strategies would be beneficial to improve the quality of life of ICU survivors.

METHODS

A prospective clinical trial was designed to compare the effects of two drugs, propofol, and dexmedetomidine, on short-term cognitive impairment after sedation in elderly ICU survivors by evaluating the extent of independence limited by the dementia-related activities of daily livings (ADLs). The plasma concentrations of brain injury biomarkers including S100β and neuron-specific enolase (NSE) were determined using an enzyme immunoassay. There were 136 patients allocated into both the dexmedetomidine group and the propofol group, respectively, with matched demographic characteristics.

RESULTS

The dementia scale of the patients in the dexmedetomidine group was significantly higher than the propofol group at weeks 1-4. Moreover, the changes in S100β and NSE concentrations in the dexmedetomidine group were significantly more pronounced than the propofol group. ICU patients who received dexmedetomidine intervention showed higher cognitive impairment than patients who received propofol, and this protective effect of propofol was not associated with the levels of brain injury markers S100β and NSE.

CONCLUSION

Our study compared the effects of commonly used medications on short-term cognitive impairment in elderly ICU patients, which would aid the selection of sedation plan for the benefit of ICU patients.

Determinants of prolonged hospitalization in patients who underwent trans-femoral transcatheter aortic valve implantation

Introduction

Transcatheter aortic valve implantation (TAVI) has grown to be an alternative treatment for severe symptomatic aortic valve stenosis (AS) in elderly patients. Although TAVI is a less invasive surgery than surgical aortic valve replacement, some patients may require prolonged hospitalization.

Aim

To find the determinants of prolonged hospitalization in patients who underwent trans-femoral TAVI.

Material and methods

A total of 94 AS patients who underwent trans-femoral TAVI were included as the final study population, and divided into the conventional hospitalization group (≤ 21 days) (n = 74) and prolonged hospitalization group (> 21 days) (n = 20). We compared clinical characteristics between the two groups, and multivariate logistic regression analysis was performed to find the determinants of prolonged hospitalization.

Results

In multivariate logistic regression analysis, moderate or severe mitral regurgitation (OR = 4.49, 95% CI: 1.16-17.47, p = 0.03), taking statins or angiotensin converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARB) on admission (statins: OR = 0.13, 95% CI: 0.02-0.71, p = 0.02, ACE inhibitors/ARB: OR = 0.25, 95% CI: 0.06-0.96, p = 0.04), estimated glomerular filtration rate (eGFR) (per 15 ml/min/1.73 m² incremental) (OR = 0.49, 95% CI: 0.26-0.90, p = 0.02) and current chopsticks user (OR = 0.05, 95% CI: 0.01-0.41, p < 0.01) were significantly associated with prolonged hospitalization.

Conclusions

Moderate or severe mitral regurgitation was significantly associated with prolonged hospitalization, while current chopsticks user, eGFR (per 15 ml/min/1.73 m² incremental), taking ACE inhibitors/ARB or statins before the procedure were inversely associated with prolonged hospitalization in patients who underwent trans-femoral TAVI.